Various forms of HIF‐1α protein characterize the clear cell renal cell carcinoma cell lines

Abstract

Renal cell carcinoma (RCC) represents around 2-3% of all malignancies diagnosed in adult patients. Most frequent (around 70-80% cases) and the most aggressive subtype is clear cell RCC (ccRCC). Mutations in VHL (von Hippel Lindau) gene, characteristic for this cancer type, lead to altered activity of the trimeric VBC (pVHL-elongin B-C) complex and consequently to HIF-1α stabilization. In this study, we present results of exhaustive investigation of HIF-1α alternative transcript variants abundance in A498, CAKI-1, and 786-O ccRCC cell lines. We proved the existence of truncated HIF-1α protein form (HIF1AΔ-6) in A498 and HIF1A gene rearrangements in 786-O cell lines. Subsequently, we found that HIF1AΔ2-6 was more stable than the full-length HIF-1α. Moreover, the shorter HIF-1α was insensitive for hypoxia and was overaccumulated after proteasome inhibitor treatment indicative of potential diversified roles of full-length and truncated HIF-1α forms in the cell. We also showed that A498, CAKI-1, and 786-O exhibit differential expression of various regulatory genes involved in the control of metabolic processes, that is, glucose and lipid metabolism, and encoding subunits of such machineries like SWI/SNF chromatin remodeling complex. Furthermore, these cell lines exhibited differential responses to axitinib, everolimus, and sunitinib-anticancer drugs-in normoxia and hypoxia as well as various alterations in metabolism-related Abbreviations: 2-OG, 2-oxoglutarate; ALDO, aldolase; ARD1, arrest-defective 1 acetyltransferase; ARNT, aryl hydrocarbon receptor nuclear translocator; bHLH, basic helix-loop-helix; ccRCC, clear cell renal cell carcinoma; CPT1A, carnitine palmitoyltransferase 1A; CUL2, cullin 2; DFO, deferoxamine; DMOG, dimethyloxaloglycine; ENO, enolase; EPAS1, endothelial PAS domain protein 1; EPO, erythropoietin; FBP1, fructose-1,6-bisphosphatase 1; FIH-1, factor inhibiting HIF-1; G6P, glucose-6-phosphatase; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; HIF1A, hypoxia inducible factor 1A; HK, hexokinase; HPH, HIF prolyl hydroxylase; HRE, hypoxia-responsive element; iNOS, inducible nitric oxide synthase; LDHA, lactate dehydrogenase A; PAS, Per-ARNT-Sim; PHD, prolyl hydroxylase; PLIN2, perilipin 2; PKM2, pyruvate kinase M2; RBX-1, Ring box 1; RCC, renal cell carcinoma; SMARCB1 (INI1), SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1; TCEB1, transcription elongation factor B (SIII); VHL, von Hippel-Lindau.

Integrated mRNA and miRNA Transcriptomic Analyses Reveals Divergent Mechanisms of Sunitinib Resistance in Clear Cell Renal Cell Carcinoma (ccRCC)

“…Even though there was a clear increase in HIF1A expression in the resistant clones of 786-O and Caki-1 cells (Figure 5; Table 3), the HIF1α protein was not detected in these cell lines (Figure 6; Table 4). This is consistent with previous studies, that have shown a lack of protein expression in 786-O cells due to mutations [41,42], and even though Caki-1 cells do encode the intact HIF1A gene, the protein is only expressed under hypoxic conditions [43]. The fact that the HIF1A transcript, but not the protein, is induced in these cell lines could have functional significance in the resistance mechanism, as several long non-coding RNAs (lncRNAs) are encoded within this gene [44,45], and this is an area we are currently investigating.…”

“…The fact that the HIF1A transcript, but not the protein, is induced in these cell lines could have functional significance in the resistance mechanism, as several long non-coding RNAs (lncRNAs) are encoded within this gene [44,45], and this is an area we are currently investigating. Although A498 cells also contain a mutated HIF1A gene, the HIF1α protein is expressed constitutively under normoxic conditions due to defective VHL [43]. We observed that HIF1α expression was down-regulated in A498-resistant clones, a characteristic that was previously described to be the result of sunitinib-associated proteosome degradation [41].…”

In-vitro antioxidant and selective cytotoxicity of Garcinia cambogia and Garcinia indica leaf extracts on human kidney cancer cell line

“…Cancer holds the top second rank when it comes to deadly disease of today's human population in entire Europe (Liu et al, 2019;Rutz et al, 2019). Among the 10 common death-causing cancers, kidney cancer is one of the debilitating health problems world wide bannering RCC as the most commonly known renal malignancy (Xu et al, 2020;Swiatek et al, 2020). Couple of years ago, 1.8 crore (18 million) new cancer cases were diagnosed globally.…”

Immune cell mediated cabozantinib resistance for patients with renal cell carcinoma

“…1A ). 786O RCC cells were chosen because they were shown to resemble ccRCC including the underlying VHL mutation [ 34 , 35 ]. After 6–8 hours allowing the cancer cells to adhere, we then coated well B with a thick layer of Matrigel ( Fig.…”