ALDH1A3 Accelerates Pancreatic Cancer Metastasis by Promoting Glucose Metabolism

Co‑expression of SLC20A1 and ALDH1A3 is associated with poor prognosis, and SLC20A1 is required for the survival of ALDH1‑positive pancreatic cancer stem cells

Solute carrier family 20 member 1 (SLC20A1) is a sodium/inorganic phosphate symporter, which has been identified as a prognostic marker in several types of cancer, including pancreatic cancer. However, to the best of our knowledge, the association between SLC20A1 expression and cancer stem cell (CSC) markers, such as aldehyde dehydrogenase 1 (ALDH1), in pancreatic ductal adenocarcinoma (PDAC), and the role of SLC20A1 in PDAC CSCs remains unclear. In the present study, a genomic dataset of primary pancreatic cancer (The Cancer Genome Atlas, Pan-Cancer Atlas) was downloaded and analyzed. Kaplan-Meier analysis and multivariate Cox regression analysis were performed to evaluate the overall survival, disease-specific survival (DSS), disease-free interval (DFI) and progression-free interval (PFI). Subsequently, SLC20A1 small interfering RNA (siRNA) knockdown (KD) was induced in the PANC-1 and MIA-PaCa-2 PDAC cell lines, and in sorted high ALDH1 activity (ALDH1high) cells, after which, cell viability, in vitro tumor sphere formation, cell death and caspase-3 activity were examined. The results revealed that patients with high expression of SLC20A1 (SLC20A1 high) at tumor stage I had a poor prognosis compared with patients with low expression of SLC20A1 (SLC20A1 low) in terms of DSS, DFI and PFI. In addition, patients with high expression of SLC20A1 and ALDH1A3 (SLC20A1 high ALDH1A3 high) exhibited poorer clinical outcomes than patients with high expression of SLC20A1 and low expression of ALDH1A3 (SLC20A1 high ALDH1A3 low), low expression of SLC20A1 and high expression of ALDH1A3 (SLC20A1 low ALDH1A3 high) and SLC20A1 low ALDH1A3 low. SLC20A1 siRNA KD in ALDH1high cells isolated from PANC-1 and MIA-PaCa-2 cell lines resulted in suppression of in vitro tumorsphere formation, and enhancement of cell death and caspase-3 activity. These results suggested that SLC20A1 was involved in cell survival via the suppression of caspase-3-dependent apoptosis, and contributed to cancer progression and poor clinical outcomes in PDAC. In conclusion, SLC20A1 may be used as a prognostic marker and novel therapeutic target of ALDH1-positive pancreatic CSCs.

Informed by Cancer Stem Cells of Solid Tumors: Advances in Treatments Targeting Tumor-Promoting Factors and Pathways

Cancer stem cells (CSCs) represent a subpopulation within tumors that promote cancer progression, metastasis, and recurrence due to their self-renewal capacity and resistance to conventional therapies. CSC-specific markers and signaling pathways highly active in CSCs have emerged as a promising strategy for improving patient outcomes. This review provides a comprehensive overview of the therapeutic targets associated with CSCs of solid tumors across various cancer types, including key molecular markers aldehyde dehydrogenases, CD44, epithelial cellular adhesion molecule, and CD133 and signaling pathways such as Wnt/β-catenin, Notch, and Sonic Hedgehog. We discuss a wide array of therapeutic modalities ranging from targeted antibodies, small molecule inhibitors, and near-infrared photoimmunotherapy to advanced genetic approaches like RNA interference, CRISPR/Cas9 technology, aptamers, antisense oligonucleotides, chimeric antigen receptor (CAR) T cells, CAR natural killer cells, bispecific T cell engagers, immunotoxins, drug-antibody conjugates, therapeutic peptides, and dendritic cell vaccines. This review spans developments from preclinical investigations to ongoing clinical trials, highlighting the innovative targeting strategies that have been informed by CSC-associated pathways and molecules to overcome therapeutic resistance. We aim to provide insights into the potential of these therapies to revolutionize cancer treatment, underscoring the critical need for a multi-faceted approach in the battle against cancer. This comprehensive analysis demonstrates how advances made in the CSC field have informed significant developments in novel targeted therapeutic approaches, with the ultimate goal of achieving more effective and durable responses in cancer patients.

ALDH1A3 contributes to tumorigenesis in high-grade serous ovarian cancer by epigenetic modification

High-grade serous ovarian cancer (HGSOC) is the most lethal histotype of ovarian cancer due to its unspecific symptoms in part. ALDH1A3 (aldehyde dehydrogenase 1 family member A3) is a key enzyme for acetyl-CoA production involving aggressive behaviors of cancers. However, ALDH1A3's effects and molecular mechanisms in HGSOC remain to be clarified. Using RNA-seq and publicly available datasets, ALDH1A3 was found to be highly expressed in HGSOC, and associated with poor survival. Knockdown of ALDH1A3 prevented HGSOC tumorigenesis and enhanced cell sensitivity to paclitaxel or cisplatin. ALDH1A3 expression in HGSOC cells was found to be increased by hypoxia, but decreased by HIF-1α inhibitor KC7F2. The dual-luciferase reporter assay showed that the increased transcriptional activity of ALDH1A3 induced by HIF-1α overexpression was reduced by KC7F2. In addition, PITX1 (paired like homeodomain 1) was identified to be inhibited by ALDH1A3 knockdown, and PITX1 depletion inhibited cell proliferation. The mechanistic studies showed that ALDH1A3 knockdown reduced the acetylation of histone 3 lysine 27 (H3K27ac). Treatment of exogenous acetate with NaOAc or inhibition of histone deacetylase with Pracinostat increased H3K27ac and PITX1 levels. CHIP assay demonstrated a significant enrichment of H3K27ac at the PITX1 promoter, and ALDH1A3 knockdown reduced the binding between H3K27ac and PITX1. Taken together, our data suggest that ALDH1A3, transcriptional activated by HIF-1α, promotes tumorigenesis and decreases chemosensitivity by increasing H3K27ac of PITX1 promoter in HGSOC.

MiR-4524b-5p-targeting ALDH1A3 attenuates the proliferation and radioresistance of glioblastoma via PI3K/AKT/mTOR signaling

Increasing evidence has revealed a strong connection between the aldehyde dehydrogenase family member ALDH1A3 and tumorigenesis, therapy resistance, and prognosis in diverse types of cancer. However, the specific miRNA involved in the pathways that regulate ALDH1A3-mediated glioblastoma (GBM) radioresistance remains to be elucidated. In this study, we demonstrated a high expression of ALDH1A3 in GBM cells, which plays a critical role in their proliferation and radioresistance. We also identified miR-4524b-5p, which is downregulated in GBM, as the ALDH1A3 upstream regulator. Overexpression of miR-4524b-5p reduced proliferation and radioresistance in GBM cells. Moreover, silencing ALDH1A3 reduced PI3K/AKT/mTOR signaling and glycolytic activity in GBM cells, whereas inhibiting mTOR reversed the radioresistance effects of ALDH1A3 on these cells. In vivo experiments have evidenced that ALDH1A3 silencing and miR-4524b-5p overexpression significantly reduced tumor growth and GBM cells radioresistance. In summary, targeting the miR-4524b-5p and ALDH1A3 axis is a promising therapeutic strategy for treating GBM.

ALDH1A3 promotes invasion and metastasis in triple-negative breast cancer by regulating the plasminogen activation pathway

Aldehyde dehydrogenase 1A3 (ALDH1A3) is a cancer stem cell marker that promotes metastasis. Triple-negative breast cancer (TNBC) progression has been linked to ALDH1A3-induced gene expression changes. To investigate the mechanism of ALDH1A3-mediated breast cancer metastasis, we assessed the effect of ALDH1A3 on the expression of proteases and the regulators of proteases that degrade the extracellular matrix, a process that is essential for invasion and metastasis. This revealed that ALDH1A3 regulates the plasminogen activation pathway; it increased the levels and activity of tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA). This resulted in a corresponding increase in the activity of serine protease plasmin, the enzymatic product of tPA and uPA. The ALDH1A3 product all-trans-retinoic acid similarly increased tPA and plasmin activity. The increased invasion of TNBC cells by ALDH1A3 was plasminogen-dependent. In patient tumours, ALDH1A3 and tPA are co-expressed and their combined expression correlated with the TNBC subtype, high tumour grade and recurrent metastatic disease. Knockdown of tPA in TNBC cells inhibited plasmin generation and lymph node metastasis. These results identify the ALDH1A3-tPA-plasmin axis as a key contributor to breast cancer progression.

ALDEFLUOR activity, ALDH isoforms, and their clinical significance in cancers

High aldehyde dehydrogenase (ALDH) activity is a metabolic feature of adult stem cells and various cancer stem cells (CSCs). The ALDEFLUOR system is currently the most commonly used method for evaluating ALDH enzyme activity in viable cells. This system is applied extensively in the isolation of normal stem cells and CSCs from heterogeneous cell populations. For many years, ALDH1A1 has been considered the most important subtype among the 19 ALDH family members in determining ALDEFLUOR activity. However, in recent years, studies of many types of normal and tumour tissues have demonstrated that other ALDH subtypes can also significantly influence ALDEFLUOR activity. In this article, we briefly review the relationships between various members of the ALDH family and ALDEFLUOR activity. The clinical significance of these ALDH isoforms in different cancers and possible directions for future studies are also summarised.

High expression of PKCλ and ALDH1A3 indicates a poor prognosis, and PKCλ is required for the asymmetric cell division of ALDH1A3-positive cancer stem cells in PDAC

Pancreatic ductal adenocarcinoma (PDAC) is the cancer with the poorest prognosis. One of the major properties reflecting its poor prognosis is high-grade heterogeneity, which leads to insensitivity to anticancer treatments. Cancer stem cells (CSCs) acquire phenotypic heterogeneity, generating abnormally differentiated cells by asymmetric cell division. However, the detailed mechanism leading to phenotypic heterogeneity is largely unknown. Here, we showed that PDAC patients with co-upregulation of PKCλ and ALDH1A3 had the poorest clinical outcome. PKCλ knockdown by DsiRNA in the ALDH1high population of PDAC MIA-PaCa-2 cells attenuated the asymmetric distribution of the ALDH1A3 protein. To monitor asymmetric cell division of ALDH1A3-positive PDAC CSCs, we established stable Panc-1 PDAC clones expressing ALDH1A3-turboGFP (Panc-1-ALDH1A3-turboGFP cells). In addition to MIA-PaCa-2-ALDH1high cells, turboGFPhigh cells sorted from Panc-1-ALDH1A3-turboGFP cells showed asymmetric cell propagation of ALDH1A3 protein. PKCλ DsiRNA in Panc-1-ALDH1A3-turboGFP cells also attenuated the asymmetric distribution of ALDH1A3 protein. These results suggest that PKCλ regulates the asymmetric cell division of ALDH1A3-positive PDAC CSCs. Furthermore, Panc-1-ALDH1A3-turboGFP cells can be useful for the visualization and monitoring of CSC properties such as asymmetric cell division of ALDH1A3-positive PDAC CSCs in time-lapse imaging.

Assessing the Link between Diabetic Metabolic Dysregulation and Breast Cancer Progression

Diabetes mellitus is a burdensome disease that affects various cellular functions through altered glucose metabolism. Several reports have linked diabetes to cancer development; however, the exact molecular mechanism of how diabetes-related traits contribute to cancer progression is not fully understood. The current study aimed to explore the molecular mechanism underlying the potential effect of hyperglycemia combined with hyperinsulinemia on the progression of breast cancer cells. To this end, gene dysregulation induced by the exposure of MCF7 breast cancer cells to hyperglycemia (HG), or a combination of hyperglycemia and hyperinsulinemia (HGI), was analyzed using a microarray gene expression assay. Hyperglycemia combined with hyperinsulinemia induced differential expression of 45 genes (greater than or equal to two-fold), which were not shared by other treatments. On the other hand, in silico analysis performed using a publicly available dataset (GEO: GSE150586) revealed differential upregulation of 15 genes in the breast tumor tissues of diabetic patients with breast cancer when compared with breast cancer patients with no diabetes. SLC26A11, ALDH1A3, MED20, PABPC4 and SCP2 were among the top upregulated genes in both microarray data and the in silico analysis. In conclusion, hyperglycemia combined with hyperinsulinemia caused a likely unique signature that contributes to acquiring more carcinogenic traits. Indeed, these findings might potentially add emphasis on how monitoring diabetes-related metabolic alteration as an adjunct to diabetes therapy is important in improving breast cancer outcomes. However, further detailed studies are required to decipher the role of the highlighted genes, in this study, in the pathogenesis of breast cancer in patients with a different glycemic index.

A Selective ALDH1A3 Inhibitor Impairs Mesothelioma 3-D Multicellular Spheroid Growth and Neutrophil Recruitment

Aldehyde dehydrogenase 1A3 (ALDH1A3), one of the three members of the aldehyde dehydrogenase 1A subfamily, has been associated with increased progression and drug resistance in various types of solid tumours. Recently, it has been reported that high ALDH1A3 expression is prognostic of poor survival in patients with malignant pleural mesothelioma (MPM), an asbestos-associated chemoresistant cancer. We treated MPM cells, cultured as multicellular spheroids, with NR6, a potent and highly selective ALDH1A3 inhibitor. Here we report that NR6 treatment caused the accumulation of toxic aldehydes, induced DNA damage, CDKN2A expression and cell growth arrest. We observed that, in CDKN2A proficient cells, NR6 treatment induced IL6 expression, but abolished CXCL8 expression and IL-8 release, preventing both neutrophil recruitment and generation of neutrophil extracellular traps (NETs). Furthermore, we demonstrate that in response to ALDH1A3 inhibition, CDKN2A loss skewed cell fate from senescence to apoptosis. Dissecting the role of ALDH1A3 isoform in MPM cells and tumour microenvironment can open new fronts in the treatment of this cancer.

Targeting aldehyde dehydrogenase enzymes in combination with chemotherapy and immunotherapy: An approach to tackle resistance in cancer cells

Modern cancer chemotherapy originated in the 1940s, and since then, many chemotherapeutic agents have been developed. However, most of these agents show limited response in patients due to innate and acquired resistance to therapy, which leads to the development of multi-drug resistance to different treatment modalities, leading to cancer recurrence and, eventually, patient death. One of the crucial players in inducing chemotherapy resistance is the aldehyde dehydrogenase (ALDH) enzyme. ALDH is overexpressed in chemotherapy-resistant cancer cells, which detoxifies the generated toxic aldehydes from chemotherapy, preventing the formation of reactive oxygen species and, thus, inhibiting the induction of oxidative stress and the stimulation of DNA damage and cell death. This review discusses the mechanisms of chemotherapy resistance in cancer cells promoted by ALDH. In addition, we provide detailed insight into the role of ALDH in cancer stemness, metastasis, metabolism, and cell death. Several studies investigated targeting ALDH in combination with other treatments as a potential therapeutic regimen to overcome resistance. We also highlight novel approaches in ALDH inhibition, including the potential synergistic employment of ALDH inhibitors in combination with chemotherapy or immunotherapy against different cancers, including head and neck, colorectal, breast, lung, and liver.

The Expanding Role of Cancer Stem Cell Marker ALDH1A3 in Cancer and Beyond

Aldehyde dehydrogenase 1A3 (ALDH1A3) is one of 19 ALDH enzymes expressed in humans, and it is critical in the production of hormone receptor ligand retinoic acid (RA). We review the role of ALDH1A3 in normal physiology, its identification as a cancer stem cell marker, and its modes of action in cancer and other diseases. ALDH1A3 is often over-expressed in cancer and promotes tumor growth, metastasis, and chemoresistance by altering gene expression, cell signaling pathways, and glycometabolism. The increased levels of ALDH1A3 in cancer occur due to genetic amplification, epigenetic modifications, post-transcriptional regulation, and post-translational modification. Finally, we review the potential of targeting ALDH1A3, with both general ALDH inhibitors and small molecules specifically designed to inhibit ALDH1A3 activity.

The Concept of Cancer Stem Cells: Elaborating on ALDH1B1 as an Emerging Marker of Cancer Progression

Cancer is a multifactorial, complex disease exhibiting extraordinary phenotypic plasticity and diversity. One of the greatest challenges in cancer treatment is intratumoral heterogeneity, which obstructs the efficient eradication of the tumor. Tumor heterogeneity is often associated with the presence of cancer stem cells (CSCs), a cancer cell sub-population possessing a panel of stem-like properties, such as a self-renewal ability and multipotency potential. CSCs are associated with enhanced chemoresistance due to the enhanced efflux of chemotherapeutic agents and the existence of powerful antioxidant and DNA damage repair mechanisms. The distinctive characteristics of CSCs make them ideal targets for clinical therapeutic approaches, and the identification of efficient and specific CSCs biomarkers is of utmost importance. Aldehyde dehydrogenases (ALDHs) comprise a wide superfamily of metabolic enzymes that, over the last years, have gained increasing attention due to their association with stem-related features in a wide panel of hematopoietic malignancies and solid cancers. Aldehyde dehydrogenase 1B1 (ALDH1B1) is an isoform that has been characterized as a marker of colon cancer progression, while various studies suggest its importance in additional malignancies. Here, we review the basic concepts related to CSCs and discuss the potential role of ALDH1B1 in cancer development and its contribution to the CSC phenotype.

Disorders of cancer metabolism: The therapeutic potential of cannabinoids

Abnormal energy metabolism, as one of the important hallmarks of cancer, was induced by multiple carcinogenic factors and tumor-specific microenvironments. It comprises aerobic glycolysis, de novo lipid biosynthesis, and glutamine-dependent anaplerosis. Considering that metabolic reprogramming provides various nutrients for tumor survival and development, it has been considered a potential target for cancer therapy. Cannabinoids have been shown to exhibit a variety of anticancer activities by unclear mechanisms. This paper first reviews the recent progress of related signaling pathways (reactive oxygen species (ROS), AMP-activated protein kinase (AMPK), mitogen-activated protein kinases (MAPK), phosphoinositide 3-kinase (PI3K), hypoxia-inducible factor-1alpha (HIF-1α), and p53) mediating the reprogramming of cancer metabolism (including glucose metabolism, lipid metabolism, and amino acid metabolism). Then we comprehensively explore the latest discoveries and possible mechanisms of the anticancer effects of cannabinoids through the regulation of the above-mentioned related signaling pathways, to provide new targets and insights for cancer prevention and treatment.

Identification of a novel prognostic ADME-related signature associated with tumor immunity for aiding therapy in head and neck squamous cell carcinoma

The genes that control drug absorption, distribution, metabolism, and excretion (ADME) are also involved in carcinogenesis, cancer progression, and chemoresistance. However, no studies have systematically investigated the clinical significance and underlying functions of ADME genes in head and neck squamous cell carcinoma. Herein, we comprehensively explored the ADME genes in this disease, constructed and validated as a prognostic ADME gene signature (ADMEGS), using three ADME genes (ABCB1, ALDH1B1, and PON2) utilizing multiple datasets, including the training and test sets of The Cancer Genome Atlas and the Gene Expression Omnibus validation set. Moreover, we analyzed the relationship between the ADMEGS and clinical parameters, tumor immunity, and therapeutic response. We found that the ADMEGS was significantly correlated with the clinical, T, and N stages. Additionally, we were able to effectively differentiate tumor immune scores, immune cell infiltration statuses, and treatment responses based on the ADMEGS. As such, ADMEGS may be promising predictors for clinical outcome, tumor immunity, and treatment response.

ALDH1: A potential therapeutic target for cancer stem cells in solid tumors

Solid tumors can be divided into benign solid tumors and solid malignant tumors in the academic community, among which malignant solid tumors are called cancers. Cancer is the second leading cause of death in the world, and the global incidence of cancer is increasing yearly New cancer patients in China are always the first. After the concept of stem cells was introduced in the tumor community, the CSC markers represented by ALDH1 have been widely studied due to their strong CSC cell characteristics and potential to be the driving force of tumor metastasis. In the research results in the past five years, it has been found that ALDH1 is highly expressed in various solid cancers such as breast cancer, lung cancer, colorectal cancer, liver cancer, gastric cancer, cervical cancer, esophageal cancer, ovarian cancer, head,and neck cancer. ALDH1 can activate and transform various pathways (such as the USP28/MYC signaling pathway, ALDH1A1/HIF-1α/VEGF axis, wnt/β-catenin signaling pathway), as well as change the intracellular pH value to promote formation and maintenance, resulting in drug resistance in tumors. By targeting and inhibiting ALDH1 in tumor stem cells, it can enhance the sensitivity of drugs and inhibit the proliferation, differentiation, and metastasis of solid tumor stem cells to some extent. This review discusses the relationship and pathway of ALDH1 with various solid tumors. It proposes that ALDH1 may serve as a diagnosis and therapeutic target for CSC, providing new insights and new strategies for reliable tumor treatment.

Targeting PI3K/AKT/mTOR Signaling Pathway in Pancreatic Cancer: From Molecular to Clinical Aspects

Although pancreatic cancer (PC) was considered in the past an orphan cancer type due to its low incidence, it may become in the future one of the leading causes of cancer death. Pancreatic ductal adenocarcinoma (PDAC) is the most frequent type of PC, being a highly aggressive malignancy and having a 5-year survival rate of less than 10%. Non-modifiable (family history, age, genetic susceptibility) and modifiable (smoking, alcohol, acute and chronic pancreatitis, diabetes mellitus, intestinal microbiota) risk factors are involved in PC pathogenesis. Chronic inflammation induced by various factors plays crucial roles in PC development from initiation to metastasis. In multiple malignant conditions such as PC, cytokines, chemokines, and growth factors activate the class I phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) (PI3K/AKT/mTOR) signaling pathway, which plays key roles in cell growth, survival, proliferation, metabolism, and motility. Currently, mTOR, AKT, and PI3K inhibitors are used in clinical studies. Moreover, PI3K/mTOR dual inhibitors are being tested in vitro and in vivo with promising results for PC patients. The main aim of this review is to present PC incidence, risk factors, tumor microenvironment development, and PI3K/AKT/mTOR dysregulation and inhibitors used in clinical, in vivo, and in vitro studies.

IGF2BP1-regulated expression of ERRα is involved in metabolic reprogramming of chemotherapy resistant osteosarcoma cells

Doxorubicin (Dox) is the standard treatment approach for osteosarcoma (OS), while acquired drug resistance seriously attenuates its treatment efficiency. The present study aimed to investigate the potential roles of metabolic reprogramming and the related regulatory mechanism in Dox-resistant OS cells. The results showed that the ATP levels, lactate generation, glucose consumption and oxygen consumption rate were significantly increased in Dox-resistant OS cells compared with parental cells. Furthermore, the results revealed that the increased expression of estrogen-related receptor alpha (ERRα) was involved in metabolic reprogramming in chemotherapy resistant OS cells, since targeted inhibition of ERRα restored the shifting of metabolic profiles. Mechanistic analysis indicated that the mRNA stability, rather than ERRα transcription was markedly increased in chemoresistant OS cells. Therefore, it was hypothesized that the 3ʹ-untranslated region of ERRα mRNA was methylated by N⁶-methyladenine, which could further recruit insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) to suppress mRNA decay and increase mRNA stability. IGF2BP1 knockdown downregulated ERRα and reversed the metabolic alteration of resistant OS cells. Additionally, the oncogenic effect of the IGF2BP1/ERRα axis on Dox-resistant OS cells was verified by in vitro and in vivo experiments. Clinical analysis also revealed that the expression levels of IGF2BP1 and ERRα were associated with the clinical progression of OS. Collectively, the current study suggested that the IGF2BP1/ERRα axis could regulate metabolic reprogramming to contribute to the chemoresistance of OS cells.

circCYP24A1 promotes Docetaxel resistance in prostate Cancer by Upregulating ALDH1A3

Background

Docetaxel (DTX) is the most widely prescribed first-line chemotherapy for advanced prostate cancer (PCa). Unfortunately, DTX resistance invariably emerges, leading to worse prognosis of PCa. Growing evidence has shown that circRNAs had complex spatiotemporal specificity during the tumor development and oncogenesis. This study was designed to investigate the biological functions and possible molecular mechanisms of circRNAs in DTX resistance of PCa.

Methods

circRNAs in established DTX-resistant DU145 cell line were identified by RNA sequencing. Biological function of circCYP24A1 was verified in vitro and in vivo. The potential role of circCYP24A1 in the development of DTX-resistant PCa was investigated via dual-luciferase reporter assays, RIP assays and RNA pull-down assays. Univariate and multivariate logistic regression analyses was used to predict DTX-chemotherapy response based on patients’ clinical and biological information.

Results

CircCYP24A1 was identified to be upregulated in DTX-resistant DU145 cells. Upregulated circCYP24A1 was found to suppress the DTX chemosensitivity in vitro and in vivo. Furthermore, we found that circCYP24A1 promoted DTX resistance in PCa via regulating ALDH1A3 expression by sponging miR-1301-3p and activating PI3K/AKT/mTOR signaling pathway. Statistical analyses elucidated that circCYP24A1 was an independent risk factor to predict DTX response (OR = 0.165; 95% CI: 0.038–0.723; P = 0.017).

Conclusions

This study demonstrated that circCYP24A played an essential role in DTX resistance in PCa, suggesting that circCYP24A1 could be a promising biomarker to predict DTX response and a potential therapeutic target in PCa patients resistant to DTX chemotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40364-022-00393-1.

Genome-Wide Selection Sweep between Wild and Local Pigs from Europe for the Investigation of the Hereditary Characteristics of Domestication in Sus Scrofa

The phenotypic characteristics of existing domestic pigs (DPs) greatly differ from those of wild boar (WB) populations thousands of years ago. After thousands of years of human domestication, WB and DP have diverged greatly in terms of genetics. Theoretically, worldwide local pigs have independent contributions from their local WBs at the beginning of Sus scrofa domestication. The investigation of the vicissitude of the heredity material between domestic populations and their wild ancestors will help in further understanding the domestication history of domestic animals. In the present study, we performed a genome-wide association scan (GWSA) and phylogeny estimation with a total of 1098 public European Illumina 60K single nucleotide polymorphism data, which included 650 local DPs and 448 WBs. The results revealed that the phylogenetic relationship of WBs corresponds to their geographical distribution and carries large divergence with DPs, and all WB breeds (e.g., HRWB, SBWB, and TIWB) presents a closely linkage with the middle WB (e.g., HRWB, and PLWB). In addition, 64 selected candidate genes (e.g., IDH2, PIP5K1B, SMARCA2, KIF5C, and TJP2) were identified from GWSA. A total of 63 known multiple biological functional pathways were annotated by 22 genes, and ubiquinone and other terpenoid-quinone biosynthesis pathways that belong to the metabolism of cofactors and vitamins were significantly enriched (p < 0.05). The most frequent (28.57%) pathways were classified under metabolism. We confirmed that the middle European WB has made an important genetic contribution to the entire European WB populations. A series of selected genes discovered from this study provides the scientific community with a deeper understanding of the heredity performance of metabolism and emotion and the real purpose behind domestication.

Integrative analysis identifies key genes related to metastasis and a robust gene-based prognostic signature in uveal melanoma

PURPOSE

Uveal melanoma (UM) is an aggressive intraocular malignancy, leading to systemic metastasis in half of the patients. However, the mechanism of the high metastatic rate remains unclear. This study aimed to identify key genes related to metastasis and construct a gene-based signature for better prognosis prediction of UM patients.

METHODS

Weighted gene co-expression network analysis (WGCNA) was used to identify the co-expression of genes primarily associated with metastasis of UM. Univariate, Lasso-penalized and multivariate Cox regression analyses were performed to establish a prognostic signature for UM patients.

RESULTS

The tan and greenyellow modules were significantly associated with the metastasis of UM patients. Significant genes related to the overall survival (OS) in these two modules were then identified. Additionally, an OS-predicting signature was established. The UM patients were divided into a low- or high-risk group. The Kaplan-Meier curve indicated that high-risk patients had poorer OS than low-risk patients. The receiver operating curve (ROC) was used to validate the stability and accuracy of the final five-gene signature. Based on the signature and clinical traits of UM patients, a nomogram was established to serve in clinical practice.

CONCLUSIONS

We identified key genes involved in the metastasis of UM. A robust five-gene-based prognostic signature was constructed and validated. In addition, the gene signature-based nomogram was created that can optimize the prognosis prediction and identify possible factors causing the poor prognosis of high-risk UM patients.

Transcriptional Expressions of ALDH1A1/B1 as Independent Indicators for the Survival of Thyroid Cancer Patients

Background

Aldehyde dehydrogenase (ALDH) 1 is an important enzyme involved in the regulation of several cellular mechanisms via aldehyde detoxification. High ALDH1 levels were correlated with tumorigenesis and stemness maintenance in cancer.

Methods

We used UALCAN, Human Protein Atlas, Kaplan–Meier plotter, TISIDB, TIMER, and KOBAS databases to investigate the expression and role of ALDH1 in thyroid cancer progression. In addition, quantitative real-time polymerase chain reaction was performed to detect the expression of the target genes in thyroid cancer cell lines and cancer tissues.

Results

Expression of ALDH1A1/B1 was significantly decreased based on individual cancer stages and tumor histology, and high levels of ALDH1A1/B1 were associated with poor overall survival in thyroid cancer patients. Moreover, ALDH1A1/B1 expression was negatively correlated with immune-stimulating genes, major histocompatibility complex, chemokines, and receptors.

Conclusions

These results suggest that ALDH1A1/B1 might serve as potential prognostic biomarkers for thyroid cancer diagnosis.

PPARγ/SOD2 Protects Against Mitochondrial ROS-Dependent Apoptosis via Inhibiting ATG4D-Mediated Mitophagy to Promote Pancreatic Cancer Proliferation

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive disease with poor prognosis. Our previous study found that peroxisome proliferator activated receptor gamma (PPARγ) was capable of enhancing glycolysis in PDAC cells. However, whether PPARγ could promote PDAC progression remains unclear. In our present study, PPARγ was positively associated with tumor size and poor prognosis in PDAC patients. Functional assays demonstrated that PPARγ could promote the proliferation of pancreatic cancer cells in vitro and in vivo. Additionally, flow cytometry results showed that PPARγ decreased mitochondrial reactive oxygen species (mitochondrial ROS) production, stabilized mitochondrial membrane potential (MMP) and inhibited cell apoptosis via up-regulating superoxide dismutase 2 (SOD2), followed by the inhibition of ATG4D-mediated mitophagy. Meanwhile, the activation of PPARγ might reduce pancreatic cancer cell stemness to improve PDAC chemosensitivity via down-regulating ATG4D. Thus, these results revealed that PPARγ/SOD2 might protect against mitochondrial ROS-dependent apoptosis via inhibiting ATG4D-mediated mitophagy to promote pancreatic cancer proliferation, further improving PDAC chemosensitivity.

Glycometabolic rearrangements-aerobic glycolysis in pancreatic ductal adenocarcinoma (PDAC): roles, regulatory networks, and therapeutic potential

INTRODUCTION

Glycometabolic rearrangements (aerobic glycolysis) is a hallmark of pancreatic ductal adenocarcinoma (PDAC) and contributes to tumorigenesis and progression through numerous mechanisms. The targeting of aerobic glycolysis is recognized as a potential therapeutic strategy which offers the possibility of improving treatment outcomes for PDAC patients.

AREAS COVERED

In this review, the role of aerobic glycolysis and its regulatory networks in PDAC are discussed. The targeting of aerobic glycolysis in PDAC is examined, and its therapeutic potential is evaluated. The relevant literature published from 2001 to 2021 was searched in databases including PubMed, Scopus, and Embase.

EXPERT OPINION

Regulatory networks of aerobic glycolysis in PDAC are based on key factors such as c-Myc, hypoxia-inducible factor 1α, the mammalian target of rapamycin pathway, and non-coding RNAs. Experimental evidence suggests that modulators or inhibitors of aerobic glycolysis promote therapeutic effects in preclinical tumor models. Nevertheless, successful clinical translation of drugs that target aerobic glycolysis in PDAC is an obstacle. Moreover, it is necessary to identify the potential targets for future interventions from regulatory networks to design efficacious and safer agents.

Pancreatic cancer cells render tumor-associated macrophages metabolically reprogrammed by a GARP and DNA methylation-mediated mechanism

How tumor-associated macrophages transit from a predominant antitumor M1-like phenotype to a protumoral M2-like phenotype during the development of pancreatic ductal adenocarcinoma (PDA) remains to be elucidated. We thus conducted a study by employing a PDA-macrophage co-culture system, an "orthotopic" PDA syngeneic mouse model, and human PDA specimens, together with macrophages derived from GARP knockout mice and multiple analytic tools including whole-genome RNA sequencing, DNA methylation arrays, multiplex immunohistochemistry, metabolism measurement, and invasion/metastasis assessment. Our study showed that PDA tumor cells, through direct cell-cell contact, induce DNA methylation and downregulation of a panel of glucose metabolism and OXPHOS genes selectively in M1-like macrophages, leading to a suppressed glucose metabolic status in M1-like but not in M2-like macrophages. Following the interaction with PDA tumor cells, M1-like macrophages are reprogrammed phenotypically to M2-like macrophages. The interaction between M1-like macrophages and PDA cells is mediated by GARP and integrin αV/β8, respectively. Blocking either GARP or integrin would suppress tumor-induced DNA methylation in Nqo-1 gene and the reprogramming of M1-like macrophages. Glucose-response genes such as Il-10 are subsequently activated in tumor-educated M1-like macrophages. Partly through Il-10 and its receptor Il-10R on tumor cells, M1-like macrophages functionally acquire a pro-cancerous capability. Both exogenous M1-like and M2-like macrophages promote metastasis in a mouse model of PDA while such a role of M1-like macrophages is dependent on DNA methylation. Our results suggest that PDA cells are able to reprogram M1-like macrophages metabolically and functionally through a GARP-dependent and DNA methylation-mediated mechanism to adopt a pro-cancerous fate.

Upregulation of KLK8 Predicts Poor Prognosis in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a growing cause of cancer-related mortality worldwide. Kallikrein-related peptidase 8 (KLK8) has potential clinical values in many cancers. However, the clinicopathological significances of KLK8 in PDAC remain unknown. We explored the relationship of KLK8 to clinicopathological features of PDAC based on public databases. KLK8 expression was examined in human PDAC tissues. Cell proliferation and apoptosis were evaluated in KLK8-overexpressed human pancreatic cancer cell lines Mia-paca-2 and Panc-1. The related signaling pathways of KLK8 involved in pancreatic cancer progression were analyzed by gene set enrichment analysis (GSEA) and further verified in in vitro studies. We found that KLK8 was up-regulated in tumor tissues in the TCGA-PAAD cohort, and was an independent prognostic factor for both overall survival and disease-free survival of PDAC. KLK8 mRNA and protein expressions were increased in PDAC tissues compared with para-cancerous pancreas. KLK8 overexpression exerted pro-proliferation and anti-apoptotic functions in Mia-paca-2 and Panc-1 cells. GSEA analysis showed that KLK8 was positively associated with PI3K-Akt-mTOR and Notch pathways. KLK8-induced pro-proliferation and anti-apoptotic effects in Mia-paca-2 and Panc-1 cells were attenuated by inhibitors for PI3K, Akt, and mTOR, but not by inhibitor for Notch. Furthermore, overexpression of KLK8 in Mia-paca-2 and Panc-1 cells significantly increased epidermal growth factor (EGF) levels in the culture media. EGF receptor (EGFR) inhibitor could block KLK8-induced activation of PI3K/Akt/mTOR pathway and attenuate pro-proliferation and anti-apoptotic of KLK8 in Mia-paca-2 and Panc-1 cells. In conclusion, KLK8 overexpression exerts pro-proliferation and anti-apoptotic functions in pancreatic cancer cells via EGF signaling-dependent activation of PI3K/Akt/mTOR pathway. Upregulated KLK8 in PDAC predicts poor prognosis and may be a potential therapeutic target for PDAC.

A short review on cross-link between pyruvate kinase (PKM2) and Glioblastoma Multiforme

Pyruvate kinase (PK) catalyzes the last irreversible reaction of glycolysis pathway, generating pyruvate and ATP, from Phosphoenol Pyruvate (PEP) and ADP precursors. In mammals, four different tissue-specific isoforms (M1, M2, L and R) of PK exist, which are translated from two genes (PKL and PKR). PKM2 is the highly expressed isoform of PK in cancers, which regulates the aerobic glycolysis via reprogramming cancer cell's metabolic pathways to provide an anabolic advantage to the tumor cells. In addition to the established role of PKM2 in aerobic glycolysis of multiple cancer types, various recent findings have highlighted the non-metabolic functions of PKM2 in brain tumor development. Nuclear PKM2 acts as a co-activator and directly regulates gene transcription. PKM2 dependent transactivation of various oncogenic genes is instrumental in the progression and aggressiveness of Glioblastoma Multiforme (GBM). Also, PKM2 acts as a protein kinase in histone modification which regulates gene expression and tumorigenesis. Ongoing research has explored novel regulatory mechanisms of PKM2 and its association in GBM progression. This review enlists and summarizes the metabolic and non-metabolic roles of PKM2 at the cellular level, and its regulatory function highlights the importance of the nuclear functions of PKM2 in GBM progression, and an emerging role of PKM2 as novel cancer therapeutics.

Identification of a novel glycolysis-related gene signature for predicting the prognosis of osteosarcoma patients

Glycolysis ensures energy supply to cancer cells, thereby facilitating tumor progression. Here, we identified glycolysis-related genes that could predict the prognosis of patients with osteosarcoma. We examined 198 glycolysis-related genes that showed differential expression in metastatic and non-metastatic osteosarcoma samples in the TARGET database, and identified three genes (P4HA1, ABCB6, and STC2) for the establishment of a risk signature. Based on the signature, patients in the high-risk group had poor outcomes. An independent Gene Expression Omnibus database GSE21257 was selected as the validation cohort. Receiver operating characteristic curve analysis was performed and the accuracy of predicting the 1- and 3-year survival rates was shown by the areas under the curve. The results were 0.884 and 0.790 in the TARGET database, and 0.740 and 0.759 in the GSE21257, respectively. Furthermore, we applied ESTIMATE algorithm and performed single sample gene set enrichment analysis to compare tumor immunity between high- and low-risk groups. We found that the low-risk group had higher immune scores and immune infiltration levels than the high-risk group. Finally, we chose P4HA1 as a representative gene to verify the function of risk genes in vitro and in vivo and found that P4HA1 could promote the metastasis of osteosarcoma cells. Our study established a novel glycolysis-related risk signature that could predict the prognosis of patients with osteosarcoma.

CSE1L, as a novel prognostic marker, promotes pancreatic cancer proliferation by regulating the AKT/mTOR signaling pathway

Pancreatic cancer is one of the most aggressive tumors with poor prognosis and new targetable therapies are urgently required. CSE1L (chromosome segregation 1 like) is thought to play an important role in tumorigenesis and acts as a cancer therapeutic target. However, the biological function and the underlying mechanism of CSE1L in pancreatic cancer are still not fully explicit. In the present study, we found that high CSE1L expression was related to a worse prognosis in patients with pancreatic cancer according to data from the Cancer Genome Atlas (TCGA) database. Additionally, we found that CSE1L knockdown inhibited the proliferation of pancreatic cancer cells and promoted apoptosis, while CSE1L overexpression demonstrated the opposite phenomenon. Furthermore, we discovered that CSE1L might regulate pancreatic cancer proliferation through AKT signaling pathway. In summary, we reveal that CSE1L plays a crucial role in tumor growth and may serve as a potential prognostic and therapeutic target for pancreatic cancer.