Ex) Article Title, Author, Keywords
Ex) Article Title, Author, Keywords
DTT 2022; 1(1): 59-66
Published online July 31, 2022
https://doi.org/10.58502/DTT.22.002
Copyright © The Pharmaceutical Society of Korea.
Correspondence to:Joohee Jung, joohee@duksung.ac.kr
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Aldehyde dehydrogenase (ALDH) catalyzes the oxidation of aldehydes and is well known to detoxify exogenous and endogenous aldehydes. ALDH has also been reported to be associated with various biological processes and is found in several tissues and organs. ALDH is classified into three groups: class 1 (cytosolic), class 2 (mitochondrial), and class 3 (organ-specific). ALDH isoforms are found in all three classes. Particularly, many studies have reported the association of ALDH isoforms with cancer. In this review, we focus on ALDH3A1. Its expression is high in lung, gastric, colorectal, liver, pancreatic, ovarian, and prostate cancer but low in oral cancer. High ALDH3A1 expression increases cell growth, motility, and invasion, associated with tumor progression in a variety of cancer except for oral cancer. Furthermore, the induction of ALDH3A1 expression via the activation of nuclear factor erythroid 2-related factor-2 induces drug resistance. ALDH3A1 reduces aldehyde-induced toxicity in the oral cavity, but low ALDH3A1 expression promotes oral cancer progression. Modulation of ALDH3A1 is anticipated to be a good target for anticancer therapy.
KeywordsALDH3A1, cancer development, tumor progression, drug resistance, cancer therapy
Aldehyde dehydrogenase (ALDH) is an enzyme that oxidizes aldehydes to carboxylic acids (Marchitti et al. 2008). ALDH catalyzes the oxidation of aldehydes through NAD (P)+-dependent enzymatic activity and detoxifies and protects cells from reactive oxygen species (Vasiliou et al. 2004; Lei et al. 2019). It is involved in multiple cellular functions, such as cellular responses to proliferation, differentiation, and survival (Jackson et al. 2011). In addition, ALDH is important for the maintenance, differentiation, and normal development of stem cells, and its expression has been reported to promote chemical resistance and survival mechanisms of cancer stem cells (Clark and Palle 2016).
ALDH is classified into three groups: class 1 (cytosolic), class 2 (mitochondrial), and class 3 (organ-specific). ALDH isoforms are found in all three classes. It is a superfamily comprising 11 families and four subfamilies and consisting of 19 genes with distinct chromosomal locations (Table 1). ALDH mainly exists in the liver and is also distributed in various tissues (cornea, kidney, pancreas, stomach, etc.). It is localized in the cytoplasm, mitochondria, endoplasmic reticulum, and nucleus of the cells (Ibrahim et al. 2018).
Table 1 Chromosome location and substrates of human ALDH
ALDH | Chromosome location | Substrate |
---|---|---|
ALDH1A1 | 9q21.13 | Retinal |
ALDH1A2 | 15q22.1 | Retinal |
ALDH1A3 | 15q26.3 | Retinal |
ALDH1B1 | 9p11.1 | Retinal & acetaldehyde |
ALDH1L1 | 3q21.2 | 10-Formyltetrahydrofolate |
ALDH1L2 | 2q23.3 | 10-Formyltetrahydrofolate |
ALDH2 | 12q24.2 | Acetaldehyde |
ALDH3A1 | 17p11.2 | Aromatic & aliphatic aldehydes |
ALDH3A2 | 17p11.2 | Fatty aldehydes |
ALDH3B1 | 11q13.2 | Octanal |
ALDH3B2 | 11q13.2 | Unknown |
ALDH4A1 | 1p36.13 | Glutamate-γ-semialdehyde |
ALDH5A1 | 6p22.2 | Succinate semialdehyde |
ALDH6A1 | 14q24.3 | Malonate semialdehyde |
ALDH7A1 | 5q31 | α-Amino adipic semialdehyde |
ALDH8A1 | 6q23.2 | Retinal |
ALDH9A1 | 1q23.1 | γ-Aminobutyraldehyde |
ALDH16A1 | 19q13.33 | Unknown |
ALDH18A1 | 10q24.3 | Glutamic- γ-semialdehyde |
ALDH subtypes have been reported to have multiple functions in various cancers. In lung cancer, co-expression of ALDH (high) and CD44 (high) is a tumor-initiating cell marker that is associated with tumorigenicity and drug resistance (Liu et al. 2013). In prostate cancer, hypermethylation of ALDH1A2 promoter region is observed, restoration of ALDH1A2 expression inhibits cell growth (Kim et al. 2005). In the liver, ALDH2 helps the clearance of acetaldehyde and protects the development of hepatocellular carcinoma (HCC) (Jin et al. 2015), and its expression inhibits metastasis of HCC by the activation of AMP-activated protein kinase signaling pathway (Hou et al. 2017). In gastric cancer MKN-45 cells, suppression of ALDH1A1 reduces cell viability, migration, and invasion by the Wnt signaling pathway (Jiang et al. 2016). In gastric cancer, low ALDH3A2 expression is associated with poor overall survival (OS) (Yin et al. 2020). Understanding the context dependent role of ALDH is critical for the development of targeted cancer therapeutics.
ALDH3A1 is highly expressed in the mammalian cornea but not in the normal liver and its main function is to filter UV radiation through the cornea (Muzio et al. 2012). ALDH3A1 expression has been reported to be highly expressed in several tumors and stem cells, and its function is investigated. It is reported to regulate several cellular functions of normal and tumor cells, such as proliferation, differentiation, survival, and response to oxidative stress (Qu et al. 2020). However, the expression and function of ALDH3A1 are different depending on cancer types. Thus, we investigated the role of ALDH3A1 in various cancers and discussed its potential as a target in cancer therapy.
The expression level of ALDH3A1 is known to be high in patients with lung cancer. Lung cancer is classified into two main types: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). The subtypes of NSCLC include adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Squamous cell cancer and adenocarcinoma have a higher expression of ALDH3A1 than that in SCLC. Thus, patients with NSCLC exhibit a higher expression level of ALDH3A1 than patients with SCLC (Patel et al. 2008). In addition, ALDH3A1 expression is induced by smoking, a carcinogen of lung cancer, and is reported to be significantly found in smokers from the large airway epithelium cells microarray data (Shahdoust et al. 2013).
In human NSCLC overexpressing ALDH3A1, the expression of epithelial to mesenchymal transition (EMT) markers such as vimentin, fibronectin, and zeb1 was increased. Pro-inflammatory and immunosuppressive mediators, such as nuclear factor-κB (NF-κB), prostaglandin E2, and interleukin-6 and -13 were also highly expressed. Consequentially, the expression of programmed cell death ligand-1 (PD-L1) on the surface of cancer cells was enhanced (Terzuoli et al. 2019). PD-L1 is known as a pro-tumorigenic factor and has shown to evade an anticancer response, indicating that it activates cell proliferation and promotes cancer progression (Han et al. 2020). ALDH3A1 has also been shown to contribute to the exosome-enhancing motility of recipient cells in the co-culture of exosomes extracted from irradiated lung cancer cells with other lung cancer cells (Wang et al. 2020a). Exosomes play an important role in intercellular communication as signaling mediators and are involved in tumor development (Milane et al. 2015).
ALDH3A1 promotes lung cancer progression and is regulated by several factors. B-cell lymphoma-2 associated athanogene 1 (Bag1) and p53 signaling pathways regulate ALDH3A1 expression (Lv et al. 2019; Fan et al. 2021). Induction of the orphan nuclear receptor (NROB1) increases ALDH3A1 expression, and proliferator-activated receptor γ suppresses its expression (Susaki et al. 2012).
ALDH3A1 is associated with drug resistance. ALDH3A1 gene is isolated as a differentially expressed gene from the paclitaxel-resistant lung adenocarcinoma A549-T cell line (Pu et al. 2020). RNAi-mediated knockdown of ALDH3A1 increases 4-hydroperoxy cyclophosphamide cytotoxicity in lung cancer A549 cells (Moreb et al. 2007). Inhibition of ALDH3A1 expression, as well as ALDH1A1 and ALDH1A3 by 4-dimethylamino-4-methylpent-2-ynthioic acid S-methylester (DIMATE, irreversible inhibitor of ALDH1 and ALDH3), overcomes specific drug resistance in NSCLC (Rebollido-Rios et al. 2020).
Gastric cancer cell lines, MKN-45 and SGC-7901, with high expression of ALDH3A1 showed decreased levels of E-cadherin and increased levels of Snail and vimentin, indicating that ALDH3A1 is associated with the induction of EMT. Increased ALDH3A1 expression is correlated with dysplasia, as well as the grade, differentiation, lymph node metastasis, and staging of gastric cancer (Wu et al. 2016). As a result of cross-talk genes analysis through differentially expressed genes screening and protein-protein interaction network database, 8 genes are found to be shared in metabolism-related pathways. Among them, ALDH3A1 shows specific classification characteristics, indicating it could be a prognosis marker in patients with gastric cancer (Zhao et al. 2017).
In gastric cancer cells, ALDH3A1 converses fatty aldehydes occurred from lipid peroxidation into fatty acids and NADH, which is needed to produce ATP, indicating ALDH3A1 contributes to providing energy sources. Thus, ALDH3A1 depletion reduces ATP production and induces apoptosis (Lee et al. 2019).
ALDH3A1 level is low in normal rectal mucosa and uniquely expressed in the squamous epithelium of the anus at anorectal junctions (Chiang et al. 2012). ALDH3A1 activity is high in colon tumor tissues (Wroczyński et al. 2005). ALDH3A1 expression increases during the transition of epithelial cells from adhesive to round dissociative forms, indicating its association with cancer cell migration, invasion, and metastasis (Tang et al. 2014). In the comparison of the transcriptome of circulating tumor cells (CTC) derived from a patient with colon cancer and colorectal cancer cells, three stemness genes, five DNA repair-related genes, and seven genes contributing to energy metabolism are significantly expressed.
In two- and three-dimension (D) KRAS-mutated colorectal cancer cells, 2-pyridine-4-yl methylene β-boswellic acid (PMBA), an inhibitor of NF-κB signaling pathway, shows a synergistic effect of 5-fluorouracil. ALDH1A2, 1A3, and 3A1 expressions increase in 3D more than in 2D colorectal cancer cells, but PMBA significantly decreases them, indicating NF-κB signaling pathway induces ALDH3A1expression (Qayum et al. 2022).
ALDH in 70% of poor differentiated human hepatocellular carcinoma (HCC) is strongly expressed (Agarwal et al. 1989; Shibuya et al. 1994). Particularly, ALDH3A1 expression is also high in HCC as well as in catenin beta 1-mutated hepatocellular adenomas and is associated with activation of the Wnt/β-catenin pathway. However, no correlation is observed between ALDH3A1 expression and OS (Calderaro et al. 2014).
NRF2, a transcriptional factor, regulates the expression of several downstream target genes such as phase I, II, and drug metabolizing enzymes. ALDH3A1, a downstream target gene of NRF2, is induced by NRF2 and is involved in xenobiotic detoxification (Wu et al. 2019). The reduction of ALDH3A1 expression by NRF2 depletion is sensitive to 5-FU (Duong et al. 2017) and gemcitabine (Matsumoto et al. 2021) in pancreatic cancer.
High-grade serous ovarian carcinoma shows a high expression of chromobox 2, which plays a role in cancer progression. Chromobox 2 knockdown decreases ALDH3A1 expression (Wheeler et al. 2018). High ALDH3A1 and ALDH1A3 expression is correlated with differentially hypomethylated genes and promotors in cisplatin-resistant ovarian yolk sac tumor cell line (NOY-1). Cisplatin-resistant NOY-1 cells involve the increase of migration, invasion and tumorigenicity (Schmidtova et al. 2020). Increasing ALDH3A1 expression correlated with cancer progression.
Pretreatment with napabucasin, a STAT3 inhibitor, inhibits chemoresistance of cancer stem cells by modulating ALDH3A1 expression (Schmidtova et al. 2020).
ALDH3A1 expression is upregulated in DU145-derived prostate stem cells and metastatic tumors (Yan et al. 2014). In prostate cancer progression, putative castration-resistant stem-like cells (CRSC) are associated with aggressiveness. Eight genes including ALDH1A1, 1A3, and 3A1 are observed as CRSC markers, ALDH overexpressed in prostate cancer tissues (Federer-Gsponer et al. 2020).
Cabazitaxel-resistant prostate cancer cells increase ALDH3A1 expression. However, shikonin enhanced the sensitivity of cabazitaxel by increasing reactive oxygen species and inhibits ALDH3A1 expression (Wang et al. 2020b). Inhibition of ALDH by (diethylamino) benzaldehyde increases chemosensitivity (Ibrahim et al. 2022).
ALDH3A1 expression is often high in minor salivary gland, tonsil and oral epithelium and its activation in the oral cavity reduces aldehyde accumulation, indicating that salivary ALDH3A1 protects against toxicants including cigarette smoke (Jang et al. 2014). ALDH3A1 activity in the saliva, cancerous, and bordering tissues of patients with oral cancers was found to be lower than that in healthy volunteers. It is associated with a higher incidence of lymph node metastasis and a poor overall survival rate (Giebułtowicz et al. 2013).
Restoration of ALDH3A1 expression inhibits proliferation, migration, and invasion of oral squamous cell carcinoma (Qu et al. 2020). Low ALDH3A1 expression levels have been shown to promote EMT in oral cancers (Vallina et al. 2021). High ALDH3A1 expression inhibits tumor-associated macrophages via the IL-6/STAT 3 signaling pathway (Qu et al. 2020) and mitochondrial reactive oxygen species, indicating that it inhibits cancer-related inflammation and suppresses tumor progression (Wang et al. 2022).
Sulforaphane (Alam et al. 2016), thymoquinone (Laskar et al. 2017), and d-limonene (Saiki et al. 2018) induce human salivary ALDH activity, suggesting it decreases the risk of oral cancer development.
This review discusses the role of ALDH3A1 in various cancers and the factors regulating ALDH3A1 expression. ALDH3A1 expression was high in lung, gastric, colorectal, liver, pancreatic, ovarian, and prostate cancers, but low in oral cancer (Table 2). As shown in Fig. 1, up-regulation of ALDH3A1 expression is associated with NROB1, NRF1, chromobox 2, and Bag1/p53 pathway, whereas ALDH3A1 expression is down-regulated by PPARγ. The mechanism and functions of ALDH3A1 are summarized in Fig. 1. ALDH3A1 promotes cell proliferation through the production of energy sources via fatty acid oxidation and enhances tumor growth, invasion, and metastasis through various pathways. Furthermore, high ALDH3A1 expression induces drug resistance. ALDH3A1 inhibitors enhance the sensitivity of anticancer drugs and suppressed cancer progression (Parajuli et al. 2014a; Parajuli et al. 2014b; Chen et al. 2015; Dinavahi et al. 2019), whereas ALDH3A1 activators protect oral cancer progression and the enzyme function from radiation (Xiao et al. 2013) (Fig. 2). Since modulation of ALDH3A1 impedes cancer progression, it could be a suitable target for anticancer therapeutic agents.
Table 2 Expression and role of ALDH3A1 in various cancers
Expression | Type of cancer | Role of ALDH3A1 | References |
---|---|---|---|
Up | Lung cancer | • Increase of EMT markers, proinflammatory immunosuppressive mediates, PD-L1 | • Terzuoli et al. 2019 |
• Enhancement of exosomes | • Wang et al. 2020a | ||
• Induction of drug resistance | • Moreb et al. 2007;Pu et al. 2020 | ||
Gastric cancer | • Decrease of E-cadherin and increase of EMT markers | • Wu et al. 2016 | |
• Provision of energy source (ATP) | • Lee et al. 2019 | ||
Colorectal cancer | • Transition from adhesive epithelial type to round dissociation type | • Tang et al. 2014 | |
• Regulation of energy metabolism in circulating tumor cells | • Alix-Panabières et al. 2017 | ||
Liver cancer | • Activation of the Wnt/β-Catenin pathway | • Calderaro et al. 2014 | |
• Induction of drug resistance | • Zhang et al. 2015 | ||
Pancreatic cancer | • Pancreatic cancer stem-like cell biomarker | • Marcato et al. 2011 | |
• Induction of drug resistance | • Duong et al. 2017; Matsumoto et al. 2021 | ||
Ovarian cancer | • Correlation of chromobox 2 expression | • Wheeler et al. 2018 | |
• Induction of drug resistance | • Schmidtova et al. 2020 | ||
Prostate cancer | • Induction of drug resistance | • Wang et al. 2020b; Ibrahim et al. 2022 | |
Down | Oral cancer | • Promotion of EMT | • Vallina et al. 2021 |
• Increase of tumor-associated macrophages and reactive oxygen species | • Qu et al. 2020 |
The expression level of ALDH3A1 is known to be high in patients with lung cancer. Lung cancer is classified into two main types: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). The subtypes of NSCLC include adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Squamous cell cancer and adenocarcinoma have a higher expression of ALDH3A1 than that in SCLC. Thus, patients with NSCLC exhibit a higher expression level of ALDH3A1 than patients with SCLC (Patel et al. 2008). In addition, ALDH3A1 expression is induced by smoking, a carcinogen of lung cancer, and is reported to be significantly found in smokers from the large airway epithelium cells microarray data (Shahdoust et al. 2013).
In human NSCLC overexpressing ALDH3A1, the expression of epithelial to mesenchymal transition (EMT) markers such as vimentin, fibronectin, and zeb1 was increased. Pro-inflammatory and immunosuppressive mediators, such as nuclear factor-κB (NF-κB), prostaglandin E2, and interleukin-6 and -13 were also highly expressed. Consequentially, the expression of programmed cell death ligand-1 (PD-L1) on the surface of cancer cells was enhanced (Terzuoli et al. 2019). PD-L1 is known as a pro-tumorigenic factor and has shown to evade an anticancer response, indicating that it activates cell proliferation and promotes cancer progression (Han et al. 2020). ALDH3A1 has also been shown to contribute to the exosome-enhancing motility of recipient cells in the co-culture of exosomes extracted from irradiated lung cancer cells with other lung cancer cells (Wang et al. 2020a). Exosomes play an important role in intercellular communication as signaling mediators and are involved in tumor development (Milane et al. 2015).
ALDH3A1 promotes lung cancer progression and is regulated by several factors. B-cell lymphoma-2 associated athanogene 1 (Bag1) and p53 signaling pathways regulate ALDH3A1 expression (Lv et al. 2019; Fan et al. 2021). Induction of the orphan nuclear receptor (NROB1) increases ALDH3A1 expression, and proliferator-activated receptor γ suppresses its expression (Susaki et al. 2012).
ALDH3A1 is associated with drug resistance. ALDH3A1 gene is isolated as a differentially expressed gene from the paclitaxel-resistant lung adenocarcinoma A549-T cell line (Pu et al. 2020). RNAi-mediated knockdown of ALDH3A1 increases 4-hydroperoxy cyclophosphamide cytotoxicity in lung cancer A549 cells (Moreb et al. 2007). Inhibition of ALDH3A1 expression, as well as ALDH1A1 and ALDH1A3 by 4-dimethylamino-4-methylpent-2-ynthioic acid S-methylester (DIMATE, irreversible inhibitor of ALDH1 and ALDH3), overcomes specific drug resistance in NSCLC (Rebollido-Rios et al. 2020).
This study was supported by the Basic Science Research Program through the NRF funded by the Ministry of Education (2021R1A6A3A01086368), the NRF grant funded by the Korean government, MSIT (2021R1A2C200453511), and the Priority Research Centers Program through the NRF funded by the Ministry of Education, Science and Technology (2016R1A6A1A03007648).
DTT 2022; 1(1): 59-66
Published online July 31, 2022 https://doi.org/10.58502/DTT.22.002
Copyright © The Pharmaceutical Society of Korea.
1Duksung Innovative Drug Center, Duksung Women's University, Seoul, Korea
2College of Pharmacy, Duksung Women’s University, Seoul, Korea
Correspondence to:Joohee Jung, joohee@duksung.ac.kr
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Aldehyde dehydrogenase (ALDH) catalyzes the oxidation of aldehydes and is well known to detoxify exogenous and endogenous aldehydes. ALDH has also been reported to be associated with various biological processes and is found in several tissues and organs. ALDH is classified into three groups: class 1 (cytosolic), class 2 (mitochondrial), and class 3 (organ-specific). ALDH isoforms are found in all three classes. Particularly, many studies have reported the association of ALDH isoforms with cancer. In this review, we focus on ALDH3A1. Its expression is high in lung, gastric, colorectal, liver, pancreatic, ovarian, and prostate cancer but low in oral cancer. High ALDH3A1 expression increases cell growth, motility, and invasion, associated with tumor progression in a variety of cancer except for oral cancer. Furthermore, the induction of ALDH3A1 expression via the activation of nuclear factor erythroid 2-related factor-2 induces drug resistance. ALDH3A1 reduces aldehyde-induced toxicity in the oral cavity, but low ALDH3A1 expression promotes oral cancer progression. Modulation of ALDH3A1 is anticipated to be a good target for anticancer therapy.
Keywords: ALDH3A1, cancer development, tumor progression, drug resistance, cancer therapy
Aldehyde dehydrogenase (ALDH) is an enzyme that oxidizes aldehydes to carboxylic acids (Marchitti et al. 2008). ALDH catalyzes the oxidation of aldehydes through NAD (P)+-dependent enzymatic activity and detoxifies and protects cells from reactive oxygen species (Vasiliou et al. 2004; Lei et al. 2019). It is involved in multiple cellular functions, such as cellular responses to proliferation, differentiation, and survival (Jackson et al. 2011). In addition, ALDH is important for the maintenance, differentiation, and normal development of stem cells, and its expression has been reported to promote chemical resistance and survival mechanisms of cancer stem cells (Clark and Palle 2016).
ALDH is classified into three groups: class 1 (cytosolic), class 2 (mitochondrial), and class 3 (organ-specific). ALDH isoforms are found in all three classes. It is a superfamily comprising 11 families and four subfamilies and consisting of 19 genes with distinct chromosomal locations (Table 1). ALDH mainly exists in the liver and is also distributed in various tissues (cornea, kidney, pancreas, stomach, etc.). It is localized in the cytoplasm, mitochondria, endoplasmic reticulum, and nucleus of the cells (Ibrahim et al. 2018).
Table 1 . Chromosome location and substrates of human ALDH.
ALDH | Chromosome location | Substrate |
---|---|---|
ALDH1A1 | 9q21.13 | Retinal |
ALDH1A2 | 15q22.1 | Retinal |
ALDH1A3 | 15q26.3 | Retinal |
ALDH1B1 | 9p11.1 | Retinal & acetaldehyde |
ALDH1L1 | 3q21.2 | 10-Formyltetrahydrofolate |
ALDH1L2 | 2q23.3 | 10-Formyltetrahydrofolate |
ALDH2 | 12q24.2 | Acetaldehyde |
ALDH3A1 | 17p11.2 | Aromatic & aliphatic aldehydes |
ALDH3A2 | 17p11.2 | Fatty aldehydes |
ALDH3B1 | 11q13.2 | Octanal |
ALDH3B2 | 11q13.2 | Unknown |
ALDH4A1 | 1p36.13 | Glutamate-γ-semialdehyde |
ALDH5A1 | 6p22.2 | Succinate semialdehyde |
ALDH6A1 | 14q24.3 | Malonate semialdehyde |
ALDH7A1 | 5q31 | α-Amino adipic semialdehyde |
ALDH8A1 | 6q23.2 | Retinal |
ALDH9A1 | 1q23.1 | γ-Aminobutyraldehyde |
ALDH16A1 | 19q13.33 | Unknown |
ALDH18A1 | 10q24.3 | Glutamic- γ-semialdehyde |
ALDH subtypes have been reported to have multiple functions in various cancers. In lung cancer, co-expression of ALDH (high) and CD44 (high) is a tumor-initiating cell marker that is associated with tumorigenicity and drug resistance (Liu et al. 2013). In prostate cancer, hypermethylation of ALDH1A2 promoter region is observed, restoration of ALDH1A2 expression inhibits cell growth (Kim et al. 2005). In the liver, ALDH2 helps the clearance of acetaldehyde and protects the development of hepatocellular carcinoma (HCC) (Jin et al. 2015), and its expression inhibits metastasis of HCC by the activation of AMP-activated protein kinase signaling pathway (Hou et al. 2017). In gastric cancer MKN-45 cells, suppression of ALDH1A1 reduces cell viability, migration, and invasion by the Wnt signaling pathway (Jiang et al. 2016). In gastric cancer, low ALDH3A2 expression is associated with poor overall survival (OS) (Yin et al. 2020). Understanding the context dependent role of ALDH is critical for the development of targeted cancer therapeutics.
ALDH3A1 is highly expressed in the mammalian cornea but not in the normal liver and its main function is to filter UV radiation through the cornea (Muzio et al. 2012). ALDH3A1 expression has been reported to be highly expressed in several tumors and stem cells, and its function is investigated. It is reported to regulate several cellular functions of normal and tumor cells, such as proliferation, differentiation, survival, and response to oxidative stress (Qu et al. 2020). However, the expression and function of ALDH3A1 are different depending on cancer types. Thus, we investigated the role of ALDH3A1 in various cancers and discussed its potential as a target in cancer therapy.
The expression level of ALDH3A1 is known to be high in patients with lung cancer. Lung cancer is classified into two main types: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). The subtypes of NSCLC include adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Squamous cell cancer and adenocarcinoma have a higher expression of ALDH3A1 than that in SCLC. Thus, patients with NSCLC exhibit a higher expression level of ALDH3A1 than patients with SCLC (Patel et al. 2008). In addition, ALDH3A1 expression is induced by smoking, a carcinogen of lung cancer, and is reported to be significantly found in smokers from the large airway epithelium cells microarray data (Shahdoust et al. 2013).
In human NSCLC overexpressing ALDH3A1, the expression of epithelial to mesenchymal transition (EMT) markers such as vimentin, fibronectin, and zeb1 was increased. Pro-inflammatory and immunosuppressive mediators, such as nuclear factor-κB (NF-κB), prostaglandin E2, and interleukin-6 and -13 were also highly expressed. Consequentially, the expression of programmed cell death ligand-1 (PD-L1) on the surface of cancer cells was enhanced (Terzuoli et al. 2019). PD-L1 is known as a pro-tumorigenic factor and has shown to evade an anticancer response, indicating that it activates cell proliferation and promotes cancer progression (Han et al. 2020). ALDH3A1 has also been shown to contribute to the exosome-enhancing motility of recipient cells in the co-culture of exosomes extracted from irradiated lung cancer cells with other lung cancer cells (Wang et al. 2020a). Exosomes play an important role in intercellular communication as signaling mediators and are involved in tumor development (Milane et al. 2015).
ALDH3A1 promotes lung cancer progression and is regulated by several factors. B-cell lymphoma-2 associated athanogene 1 (Bag1) and p53 signaling pathways regulate ALDH3A1 expression (Lv et al. 2019; Fan et al. 2021). Induction of the orphan nuclear receptor (NROB1) increases ALDH3A1 expression, and proliferator-activated receptor γ suppresses its expression (Susaki et al. 2012).
ALDH3A1 is associated with drug resistance. ALDH3A1 gene is isolated as a differentially expressed gene from the paclitaxel-resistant lung adenocarcinoma A549-T cell line (Pu et al. 2020). RNAi-mediated knockdown of ALDH3A1 increases 4-hydroperoxy cyclophosphamide cytotoxicity in lung cancer A549 cells (Moreb et al. 2007). Inhibition of ALDH3A1 expression, as well as ALDH1A1 and ALDH1A3 by 4-dimethylamino-4-methylpent-2-ynthioic acid S-methylester (DIMATE, irreversible inhibitor of ALDH1 and ALDH3), overcomes specific drug resistance in NSCLC (Rebollido-Rios et al. 2020).
Gastric cancer cell lines, MKN-45 and SGC-7901, with high expression of ALDH3A1 showed decreased levels of E-cadherin and increased levels of Snail and vimentin, indicating that ALDH3A1 is associated with the induction of EMT. Increased ALDH3A1 expression is correlated with dysplasia, as well as the grade, differentiation, lymph node metastasis, and staging of gastric cancer (Wu et al. 2016). As a result of cross-talk genes analysis through differentially expressed genes screening and protein-protein interaction network database, 8 genes are found to be shared in metabolism-related pathways. Among them, ALDH3A1 shows specific classification characteristics, indicating it could be a prognosis marker in patients with gastric cancer (Zhao et al. 2017).
In gastric cancer cells, ALDH3A1 converses fatty aldehydes occurred from lipid peroxidation into fatty acids and NADH, which is needed to produce ATP, indicating ALDH3A1 contributes to providing energy sources. Thus, ALDH3A1 depletion reduces ATP production and induces apoptosis (Lee et al. 2019).
ALDH3A1 level is low in normal rectal mucosa and uniquely expressed in the squamous epithelium of the anus at anorectal junctions (Chiang et al. 2012). ALDH3A1 activity is high in colon tumor tissues (Wroczyński et al. 2005). ALDH3A1 expression increases during the transition of epithelial cells from adhesive to round dissociative forms, indicating its association with cancer cell migration, invasion, and metastasis (Tang et al. 2014). In the comparison of the transcriptome of circulating tumor cells (CTC) derived from a patient with colon cancer and colorectal cancer cells, three stemness genes, five DNA repair-related genes, and seven genes contributing to energy metabolism are significantly expressed.
In two- and three-dimension (D) KRAS-mutated colorectal cancer cells, 2-pyridine-4-yl methylene β-boswellic acid (PMBA), an inhibitor of NF-κB signaling pathway, shows a synergistic effect of 5-fluorouracil. ALDH1A2, 1A3, and 3A1 expressions increase in 3D more than in 2D colorectal cancer cells, but PMBA significantly decreases them, indicating NF-κB signaling pathway induces ALDH3A1expression (Qayum et al. 2022).
ALDH in 70% of poor differentiated human hepatocellular carcinoma (HCC) is strongly expressed (Agarwal et al. 1989; Shibuya et al. 1994). Particularly, ALDH3A1 expression is also high in HCC as well as in catenin beta 1-mutated hepatocellular adenomas and is associated with activation of the Wnt/β-catenin pathway. However, no correlation is observed between ALDH3A1 expression and OS (Calderaro et al. 2014).
NRF2, a transcriptional factor, regulates the expression of several downstream target genes such as phase I, II, and drug metabolizing enzymes. ALDH3A1, a downstream target gene of NRF2, is induced by NRF2 and is involved in xenobiotic detoxification (Wu et al. 2019). The reduction of ALDH3A1 expression by NRF2 depletion is sensitive to 5-FU (Duong et al. 2017) and gemcitabine (Matsumoto et al. 2021) in pancreatic cancer.
High-grade serous ovarian carcinoma shows a high expression of chromobox 2, which plays a role in cancer progression. Chromobox 2 knockdown decreases ALDH3A1 expression (Wheeler et al. 2018). High ALDH3A1 and ALDH1A3 expression is correlated with differentially hypomethylated genes and promotors in cisplatin-resistant ovarian yolk sac tumor cell line (NOY-1). Cisplatin-resistant NOY-1 cells involve the increase of migration, invasion and tumorigenicity (Schmidtova et al. 2020). Increasing ALDH3A1 expression correlated with cancer progression.
Pretreatment with napabucasin, a STAT3 inhibitor, inhibits chemoresistance of cancer stem cells by modulating ALDH3A1 expression (Schmidtova et al. 2020).
ALDH3A1 expression is upregulated in DU145-derived prostate stem cells and metastatic tumors (Yan et al. 2014). In prostate cancer progression, putative castration-resistant stem-like cells (CRSC) are associated with aggressiveness. Eight genes including ALDH1A1, 1A3, and 3A1 are observed as CRSC markers, ALDH overexpressed in prostate cancer tissues (Federer-Gsponer et al. 2020).
Cabazitaxel-resistant prostate cancer cells increase ALDH3A1 expression. However, shikonin enhanced the sensitivity of cabazitaxel by increasing reactive oxygen species and inhibits ALDH3A1 expression (Wang et al. 2020b). Inhibition of ALDH by (diethylamino) benzaldehyde increases chemosensitivity (Ibrahim et al. 2022).
ALDH3A1 expression is often high in minor salivary gland, tonsil and oral epithelium and its activation in the oral cavity reduces aldehyde accumulation, indicating that salivary ALDH3A1 protects against toxicants including cigarette smoke (Jang et al. 2014). ALDH3A1 activity in the saliva, cancerous, and bordering tissues of patients with oral cancers was found to be lower than that in healthy volunteers. It is associated with a higher incidence of lymph node metastasis and a poor overall survival rate (Giebułtowicz et al. 2013).
Restoration of ALDH3A1 expression inhibits proliferation, migration, and invasion of oral squamous cell carcinoma (Qu et al. 2020). Low ALDH3A1 expression levels have been shown to promote EMT in oral cancers (Vallina et al. 2021). High ALDH3A1 expression inhibits tumor-associated macrophages via the IL-6/STAT 3 signaling pathway (Qu et al. 2020) and mitochondrial reactive oxygen species, indicating that it inhibits cancer-related inflammation and suppresses tumor progression (Wang et al. 2022).
Sulforaphane (Alam et al. 2016), thymoquinone (Laskar et al. 2017), and d-limonene (Saiki et al. 2018) induce human salivary ALDH activity, suggesting it decreases the risk of oral cancer development.
This review discusses the role of ALDH3A1 in various cancers and the factors regulating ALDH3A1 expression. ALDH3A1 expression was high in lung, gastric, colorectal, liver, pancreatic, ovarian, and prostate cancers, but low in oral cancer (Table 2). As shown in Fig. 1, up-regulation of ALDH3A1 expression is associated with NROB1, NRF1, chromobox 2, and Bag1/p53 pathway, whereas ALDH3A1 expression is down-regulated by PPARγ. The mechanism and functions of ALDH3A1 are summarized in Fig. 1. ALDH3A1 promotes cell proliferation through the production of energy sources via fatty acid oxidation and enhances tumor growth, invasion, and metastasis through various pathways. Furthermore, high ALDH3A1 expression induces drug resistance. ALDH3A1 inhibitors enhance the sensitivity of anticancer drugs and suppressed cancer progression (Parajuli et al. 2014a; Parajuli et al. 2014b; Chen et al. 2015; Dinavahi et al. 2019), whereas ALDH3A1 activators protect oral cancer progression and the enzyme function from radiation (Xiao et al. 2013) (Fig. 2). Since modulation of ALDH3A1 impedes cancer progression, it could be a suitable target for anticancer therapeutic agents.
Table 2 . Expression and role of ALDH3A1 in various cancers.
Expression | Type of cancer | Role of ALDH3A1 | References |
---|---|---|---|
Up | Lung cancer | • Increase of EMT markers, proinflammatory immunosuppressive mediates, PD-L1 | • Terzuoli et al. 2019 |
• Enhancement of exosomes | • Wang et al. 2020a | ||
• Induction of drug resistance | • Moreb et al. 2007;Pu et al. 2020 | ||
Gastric cancer | • Decrease of E-cadherin and increase of EMT markers | • Wu et al. 2016 | |
• Provision of energy source (ATP) | • Lee et al. 2019 | ||
Colorectal cancer | • Transition from adhesive epithelial type to round dissociation type | • Tang et al. 2014 | |
• Regulation of energy metabolism in circulating tumor cells | • Alix-Panabières et al. 2017 | ||
Liver cancer | • Activation of the Wnt/β-Catenin pathway | • Calderaro et al. 2014 | |
• Induction of drug resistance | • Zhang et al. 2015 | ||
Pancreatic cancer | • Pancreatic cancer stem-like cell biomarker | • Marcato et al. 2011 | |
• Induction of drug resistance | • Duong et al. 2017; Matsumoto et al. 2021 | ||
Ovarian cancer | • Correlation of chromobox 2 expression | • Wheeler et al. 2018 | |
• Induction of drug resistance | • Schmidtova et al. 2020 | ||
Prostate cancer | • Induction of drug resistance | • Wang et al. 2020b; Ibrahim et al. 2022 | |
Down | Oral cancer | • Promotion of EMT | • Vallina et al. 2021 |
• Increase of tumor-associated macrophages and reactive oxygen species | • Qu et al. 2020 |
The expression level of ALDH3A1 is known to be high in patients with lung cancer. Lung cancer is classified into two main types: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). The subtypes of NSCLC include adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Squamous cell cancer and adenocarcinoma have a higher expression of ALDH3A1 than that in SCLC. Thus, patients with NSCLC exhibit a higher expression level of ALDH3A1 than patients with SCLC (Patel et al. 2008). In addition, ALDH3A1 expression is induced by smoking, a carcinogen of lung cancer, and is reported to be significantly found in smokers from the large airway epithelium cells microarray data (Shahdoust et al. 2013).
In human NSCLC overexpressing ALDH3A1, the expression of epithelial to mesenchymal transition (EMT) markers such as vimentin, fibronectin, and zeb1 was increased. Pro-inflammatory and immunosuppressive mediators, such as nuclear factor-κB (NF-κB), prostaglandin E2, and interleukin-6 and -13 were also highly expressed. Consequentially, the expression of programmed cell death ligand-1 (PD-L1) on the surface of cancer cells was enhanced (Terzuoli et al. 2019). PD-L1 is known as a pro-tumorigenic factor and has shown to evade an anticancer response, indicating that it activates cell proliferation and promotes cancer progression (Han et al. 2020). ALDH3A1 has also been shown to contribute to the exosome-enhancing motility of recipient cells in the co-culture of exosomes extracted from irradiated lung cancer cells with other lung cancer cells (Wang et al. 2020a). Exosomes play an important role in intercellular communication as signaling mediators and are involved in tumor development (Milane et al. 2015).
ALDH3A1 promotes lung cancer progression and is regulated by several factors. B-cell lymphoma-2 associated athanogene 1 (Bag1) and p53 signaling pathways regulate ALDH3A1 expression (Lv et al. 2019; Fan et al. 2021). Induction of the orphan nuclear receptor (NROB1) increases ALDH3A1 expression, and proliferator-activated receptor γ suppresses its expression (Susaki et al. 2012).
ALDH3A1 is associated with drug resistance. ALDH3A1 gene is isolated as a differentially expressed gene from the paclitaxel-resistant lung adenocarcinoma A549-T cell line (Pu et al. 2020). RNAi-mediated knockdown of ALDH3A1 increases 4-hydroperoxy cyclophosphamide cytotoxicity in lung cancer A549 cells (Moreb et al. 2007). Inhibition of ALDH3A1 expression, as well as ALDH1A1 and ALDH1A3 by 4-dimethylamino-4-methylpent-2-ynthioic acid S-methylester (DIMATE, irreversible inhibitor of ALDH1 and ALDH3), overcomes specific drug resistance in NSCLC (Rebollido-Rios et al. 2020).
This study was supported by the Basic Science Research Program through the NRF funded by the Ministry of Education (2021R1A6A3A01086368), the NRF grant funded by the Korean government, MSIT (2021R1A2C200453511), and the Priority Research Centers Program through the NRF funded by the Ministry of Education, Science and Technology (2016R1A6A1A03007648).
Table 1 Chromosome location and substrates of human ALDH
ALDH | Chromosome location | Substrate |
---|---|---|
ALDH1A1 | 9q21.13 | Retinal |
ALDH1A2 | 15q22.1 | Retinal |
ALDH1A3 | 15q26.3 | Retinal |
ALDH1B1 | 9p11.1 | Retinal & acetaldehyde |
ALDH1L1 | 3q21.2 | 10-Formyltetrahydrofolate |
ALDH1L2 | 2q23.3 | 10-Formyltetrahydrofolate |
ALDH2 | 12q24.2 | Acetaldehyde |
ALDH3A1 | 17p11.2 | Aromatic & aliphatic aldehydes |
ALDH3A2 | 17p11.2 | Fatty aldehydes |
ALDH3B1 | 11q13.2 | Octanal |
ALDH3B2 | 11q13.2 | Unknown |
ALDH4A1 | 1p36.13 | Glutamate-γ-semialdehyde |
ALDH5A1 | 6p22.2 | Succinate semialdehyde |
ALDH6A1 | 14q24.3 | Malonate semialdehyde |
ALDH7A1 | 5q31 | α-Amino adipic semialdehyde |
ALDH8A1 | 6q23.2 | Retinal |
ALDH9A1 | 1q23.1 | γ-Aminobutyraldehyde |
ALDH16A1 | 19q13.33 | Unknown |
ALDH18A1 | 10q24.3 | Glutamic- γ-semialdehyde |
Table 2 Expression and role of ALDH3A1 in various cancers
Expression | Type of cancer | Role of ALDH3A1 | References |
---|---|---|---|
Up | Lung cancer | • Increase of EMT markers, proinflammatory immunosuppressive mediates, PD-L1 | • Terzuoli et al. 2019 |
• Enhancement of exosomes | • Wang et al. 2020a | ||
• Induction of drug resistance | • Moreb et al. 2007;Pu et al. 2020 | ||
Gastric cancer | • Decrease of E-cadherin and increase of EMT markers | • Wu et al. 2016 | |
• Provision of energy source (ATP) | • Lee et al. 2019 | ||
Colorectal cancer | • Transition from adhesive epithelial type to round dissociation type | • Tang et al. 2014 | |
• Regulation of energy metabolism in circulating tumor cells | • Alix-Panabières et al. 2017 | ||
Liver cancer | • Activation of the Wnt/β-Catenin pathway | • Calderaro et al. 2014 | |
• Induction of drug resistance | • Zhang et al. 2015 | ||
Pancreatic cancer | • Pancreatic cancer stem-like cell biomarker | • Marcato et al. 2011 | |
• Induction of drug resistance | • Duong et al. 2017; Matsumoto et al. 2021 | ||
Ovarian cancer | • Correlation of chromobox 2 expression | • Wheeler et al. 2018 | |
• Induction of drug resistance | • Schmidtova et al. 2020 | ||
Prostate cancer | • Induction of drug resistance | • Wang et al. 2020b; Ibrahim et al. 2022 | |
Down | Oral cancer | • Promotion of EMT | • Vallina et al. 2021 |
• Increase of tumor-associated macrophages and reactive oxygen species | • Qu et al. 2020 |