Lukiyanchuk, V. | bioRxiv Science

bioRxiv2021

The distinct role of ALDH1A1 and ALDH1A3 in the regulation of prostate cancer metastases

Cancer stem cells (CSC) are characterized by high self-renewal capacity, tumor-initiating potential, and therapy resistance. Aldehyde dehydrogenase (ALDH)+ cell population serves as an indicator of prostate CSCs with increased therapy resistance, enhanced DNA double-strand break repair, and activated epithelial-mesenchymal transition (EMT) and migration. Numerous ALDH genes contribute to ALDH enzymatic activity; however, only some of them showed clinical relevance. We found that ALDH1A1 and ALDH1A3 genes functionally regulate CSC properties and radiation sensitivity of PCa. We revealed a negative correlation between ALDH1A1 and ALDH1A3 expression in publicly available prostate cancer (PCa) datasets and demonstrated that ALDH1A1 and ALDH1A3 have opposing predictive value for biochemical recurrence-free survival. Our data suggest an association of ALDH1A1 with the metastatic burden, elucidating the role of ALDH genes in the metastatic spread and homing to the bone, which can be, at least partially, attributed to regulating the transforming growth factor beta 1 (TGFB1) and matrix metalloproteinases (MMPs). ALDH genes play a diverse role in PCa development under AR and {beta}-catenin-dependent regulation, with ALDH1A1 becoming dominant in later stages of tumor development when PCa cells gain androgen independence. Taken together, our results indicate that ALDH1A1 and ALDH1A3 modulate PCa radiosensitivity, regulate CSCs phenotype, and spread of PCa cells to the bone, therefore having clinical implication for identifying patients at high risk for progression to metastatic disease.

cancer biology↗

bioRxiv2021

GLS-driven glutamine catabolism contributes to prostate cancer radiosensitivity by regulating the redox state, stemness and ATG5-mediated autophagy

Radiotherapy is one of the curative treatment options for localized prostate cancer (PCa). The curative potential of radiotherapy is mediated by irradiation-induced oxidative stress and DNA damage in tumor cells. However, PCa radiocurability can be impeded by tumor resistance mechanisms and normal tissue toxicity. Metabolic reprogramming is one of the major hallmarks of tumor progression and therapy resistance. Here, we found that radioresistant PCa cells and prostate cancer stem cells (CSCs) have a high glutamine demand. Glutaminase (GLS)-driven catabolism of glutamine serves not only for energy production but also for the maintenance of the redox state. Consequently, glutamine depletion or inhibition of critical regulators of glutamine utilization, such as glutaminase (GLS) and the transcription factor MYC results in PCa radiosensitization. On the contrary, we found that a combination of glutamine metabolism inhibitors with irradiation does not cause toxic effects on nonmalignant prostate cells. Glutamine catabolism contributes to the maintenance of CSCs through regulation of the alpha-ketoglutarate (-KG)-dependent chromatin-modifying dioxygenase. The lack of glutamine results in the inhibition of CSCs with a high aldehyde dehydrogenase (ALDH) activity, decreases the frequency of the CSC populations in vivo and reduces tumor formation in xenograft mouse models. Moreover, this study shows that activation of the ATG5-mediated autophagy in response to a lack of glutamine is a tumor survival strategy to withstand radiation-mediated cell damage. In combination with autophagy inhibition, the blockade of glutamine metabolism might be a promising strategy for PCa radiosensitization. High blood levels of glutamine in PCa patients significantly correlate with a shorter prostate-specific antigen (PSA) doubling time. Furthermore, high expression of critical regulators of glutamine metabolism, GLS1 and MYC, is significantly associated with a decreased progression-free survival in PCa patients treated with radiotherapy. Our findings demonstrate that GLS-driven glutaminolysis is a prognostic biomarker and therapeutic target for PCa radiosensitization.

cancer biology↗