Carnitine Palmitoyltransferase 1 Regulates Prostate Cancer Growth under Hypoxia

Abstract

Hypoxia and hypoxia-related biomarkers are the major determinants of prostate cancer (PCa) aggressiveness. Therefore, a better understanding of molecular players involved in PCa cell survival under hypoxia could offer novel therapeutic targets. We previously reported a central role of mitochondrial protein carnitine palmitoyltransferase (CPT1A) in PCa progression, but its role in regulating PCa survival under hypoxia remains unknown. Here, we employed PCa cells (22Rv1 and MDA-PCa-2b) with knockdown or overexpression of CPT1A and assessed their survival under hypoxia, both in cell culture and in vivo models. The results showed that CPT1A knockdown in PCa cells significantly reduced their viability, clonogenicity, and sphere formation under hypoxia, while its overexpression increased their proliferation, clonogenicity, and sphere formation. In nude mice, 22Rv1 xenografts with CPT1A knockdown grew significantly slower compared to vector control cells (~59% reduction in tumor volume at day 29). On the contrary, CPT1A-overexpressing 22Rv1 xenografts showed higher tumor growth compared to vector control cells (~58% higher tumor volume at day 40). Pathological analyses revealed lesser necrotic areas in CPT1A knockdown tumors and higher necrotic areas in CPT1A overexpressing tumors. Immunofluorescence analysis of tumors showed that CPT1A knockdown strongly compromised the hypoxic areas (pimonidazole+), while CPT1A overexpression resulted in more hypoxia areas with strong expression of proliferation biomarkers (Ki67 and cyclin D1). Finally, IHC analysis of tumors revealed a significant decrease in VEGF or VEGF-D expression but without significant changes in biomarkers associated with microvessel density. These results suggest that CPT1A regulates PCa survival in hypoxic conditions and might contribute to their aggressiveness.

SUBATOMIC: a SUbgraph BAsed mulTi-OMIcs clustering framework to analyze integrated multi-edge networks

“…Especially PPARG was shown to be activated under hypoxic conditions in correlation with HIF1A in lung cancer and hepatocellular carcinoma [ 76 , 77 ]. It regulated the differentially expressed gene carnitine palmitoyltransferase 1A (CPT1A) and its homolog CPT1B, shown to regulate prostate cancer growth under hypoxic conditions [ 78 ]. While this module does not show strong dysregulation in the three analyzed cancer types, it contained genes and interactions highly relevant in reaction to hypoxia, as demonstrated in other studies.…”

Identification of a Mitochondria-Related Gene Signature to Predict the Prognosis in AML

“…Abnormal CPT1A expression was associated with the poor OS of AML (43), ovarian cancer (44), and glioblastoma stem cells (45). Leslimar et al reported that CPT1A could regulate prostate cancer survival in hypoxic conditions and promote aggressiveness (46). IDH3A, isocitrate dehydrogenases 3 Catalytic Subunit Alpha, is the key part of isocitrate dehydrogenases, catalyzing the oxidative decarboxylation of isocitrate to a-ketoglutarate in citrate cycle (47).…”

Role of extracellular vesicles secretion in paclitaxel resistance of prostate cancer cells

“…Tumor tissues were processed, and 5 µm formalin-fixed and paraffin-embedded (FFPE) sections were analyzed for CD63 expression by processing and immunohistochemistry (IHC) as described by us previously [ 39 ] . CD63 primary antibody was purchased from ThermoFisher (Waltham, MA) and detection system (ImmPRESS-AP horse anti-rabbit IgG polymer detection kit) with secondary antibody from Vector laboratories (Burlingame, CA).…”

“…The concentration and size distribution of the EVs were analyzed using Nanosight NS300 (Malvern Instruments, UK) as described earlier [38] .…”

“…Isolation of total EVs from mice plasma was performed as described by us previously [38,40] . Briefly, plasma was diluted in PBS and centrifuged at 500 g for 5 min, 2,000 g for 10 min, followed by 10,000 g for 30 min at 4 ℃ to remove the larger sized vesicles.…”