EFFECTS OF HEME OXYGENASE 1 (HO-1) EXPRESSION ON METASTASIS AND STEMNESS-ASSOCIATED GENES IN PROSTATE CANCER

SABATER, AGUSTINA; TORO, AYELEN; SANCHIS, PABLO; PASCUAL, GASTON; SENIUK, ROCIO; VAZQUEZ, ELBA; COTIGNOLA, JAVIER; GUERON, GERALDINE; BIZZOTTO, JUAN; LAGE-VICKERS, SOFIA

Congreso; Prostate Cancer Foundation Scientific Retreat 2021; 2021

BACKGROUND: Within prostate cancer (PCa) tumors, there is a sub-population of cancer stem cells (CSCs) that enhances the tumor?s capacity to proliferate, metastasize, and provide resistance to therapy. Thus, stemness represents a therapeutic challenge in PCa. The inflammatory tumor microenvironment is a fertile niche that releases reactive oxygen species (ROS), which accelerate the malignant transformation. Heme oxygenase 1 (HO-1), the rate-limiting enzyme in heme degradation, is an essential player in cellular responses to pro-oxidative and pro-inflammatory insults. We have reported that HO-1 has a strong anti-tumoral effect in prostate carcinogenesis in vivo and in vitro, ascertaining it as a logical target for intervention therapy in PCa. However, its association with metastasis-stemness is still poorly elucidated. In this work, we aimed at describing the effects of HO-1 overexpression on metastasis/stemness in PCa by also identifying key genes associated with these processes that could be modulated by HO-1 induction.METHODS: First, we performed clonogenic assays to evaluate the effect of HO-1 pharmacological induction by hemin on the stem properties of PCa cells. Next, we carried out a comprehensive RNA-seq analysis to assess the differences at the transcriptional level of 144 metastasis/stemness/STAT3 signature genes1?6 in PC3 hemin vs. PC3 control. The clinical significance of HO-1 modulated genes was assessed by comprehensive bioinformatics analyses using public data repositories with gene expression and survival data of PCa patients (Oncomine 7 (n = 1128), TCGA-PRAD 8 (n = 565)). RNA-seq results were validated by RT-qPCR. RESULTS: Clonogenic assays results showed a significant reduction in colony formation efficiency after HO-1 pharmacological induction with hemin (p ≤ 0.01). Transcriptomics profiling by RNA-seq evidenced a significant modulation of 32 key markers related to metastasis/stemness/STAT3 signature under HO-1 induction. Further, 15 out of the 32 significantly HO-1-modulated genes were differentially expressed in prostate adenocarcinoma vs. normal prostate gland (Oncomine) and HO-1 pharmacological induction reverted the expression profile observed for these genes in the same comparison. We then used an independent non-overlapping dataset (TCGA-PRAD) which revealed that ADAM15, BCL2L1, LTBR, MBNL2 and SPINT1 had the same expression profile as the one observed for prostate adenocarcinoma vs normal gland human samples (Oncomine). Additionally, PCa patients on the TCGA-PRAD dataset with high MBNL2 expression showed a longer disease progression free survival, which is interesting as this gene is upregulated in PC3 cells overexpressing HO-1. We validated this modulation by RT-qPCR. CONCLUSIONS: HO-1 is capable of modulating key metastasis/stemness-associated genes relevant in PCa progression. We point out a new potential mechanism by which HO-1 could inhibit PCa progression. This study may cast a new light on PCa treatment, highlighting a multifaceted role for HO-1 in altering progression processes by modulating cell plasticity, thus supporting it as a potential therapeutic target for the disease.FUNDING ACKNOWLEDGEMENTS: This work was supported by grants from Agencia Nacional de Promocion de la Investigación, el Desarollo Tecnológico y la Innovación (ANPCyT), Argentina: PICT-2016-0056, PICT-RAICES-2018-02639; PICT-2019-2019-03215; and Universidad de Buenos Aires, Argentina: 20020170100585BA.CONFLICTS OF INTEREST DISCLOSURE STATEMENT: Authors declare no conflicts of interest.REFERENCES:1.Huang, R. et al. CCL5 derived from tumor-associated macrophages promotes prostate cancer stem cells and metastasis via activating β-catenin/STAT3 signaling. Cell Death Dis. 2020 114 11, 1?20 (2020).2.Sharpe, B., Beresford, M., Bowen, R., Mitchard, J. & Chalmers, A. D. Searching for Prostate Cancer Stem Cells: Markers and Methods. Stem Cell Rev. Reports 9, 721?730 (2013).3.Maitland, N. J., Frame, F. M., Polson, E. S., Lewis, J. L. & Collins, A. T. Prostate Cancer Stem Cells: Do They Have a Basal or Luminal Phenotype? Horm. Cancer 2, 47?61 (2011).4.Leong, K. G., Wang, B. E., Johnson, L. & Gao, W. Q. Generation of a prostate from a single adult stem cell. Nature 456, 804?810 (2008).5.Goldstein, A. S., Huang, J., Guo, C., Garraway, I. P. & Witte, O. N. Identification of a cell of origin for human prostate cancer. Science (80-. ). 329, 568?571 (2010).6.Collins, A. T., Berry, P. A., Hyde, C., Stower, M. J. & Maitland, N. J. Prospective identification of tumorigenic prostate cancer stem cells. Cancer Res. 65, 10946?10951 (2005).7.Rhodes, D. R. et al. ONCOMINE: A Cancer Microarray Database and Integrated Data-Mining Platform. Neoplasia 6, 1?6 (2004).8.The Cancer Genome Atlas Program - National Cancer Institute. National Institute of Health https://www.cancer.gov/about-nci/organization/ccg/research/structural-genomics/tcga (2020).