MIR21 Drives Resistance to Heat Shock Protein 90 Inhibition in Cholangiocarcinoma

Abstract

Background & AimsCholangiocarcinomas (CCA) are resistant to chemotherapy, so new therapeutic agents are needed. We performed a screen to identify small-molecule compounds that are active against CCAs. Levels of microRNA 21 (MIR21 or miRNA21) are increased in CCAs. We investigated whether miRNA21 mediates resistance of CCA cells and organoids to HSP90 inhibitors.MethodsWe performed a high-throughput screen of 484 small-molecule compounds to identify those that reduced viability of 6 human CCA cell lines. We tested the effects of HSP90 inhibitors on cells with disruption of the MIR21 gene, cells incubated with MIR21 inhibitors, and stable cell lines with inducible expression of MIR21. We obtained CCA biopsies from patients, cultured them as organoids (patient-derived organoids). We assessed their architecture, mutation and gene expression patterns, response to compounds in culture, and when grown as subcutaneous xenograft tumors in mice.ResultsCells with IDH1 and PBRM1 mutations had the highest level of sensitivity to histone deacetylase inhibitors. HSP90 inhibitors were effective in all cell lines, irrespective of mutations. Sensitivity of cells to HSP90 inhibitors correlated inversely with baseline level of MIR21. Disruption of MIR21 increased cell sensitivity to HSP90 inhibitors. CCA cells that expressed transgenic MIR21 were more resistant to HSP90 inhibitors than cells transfected with control vectors; inactivation of MIR21 in these cells restored sensitivity to these agents. MIR21 was shown to target the DnaJ heat shock protein family (Hsp40) member B5 (DNAJB5). Transgenic expression of DNAJB5 in CCA cells that overexpressed MIR21 re-sensitized them to HSP90 inhibitors. Sensitivity of patient-derived organoids to HSP90 inhibitors, in culture and when grown as xenograft tumors in mice, depended on expression of miRNA21.ConclusionsmiRNA21 appears to mediate resistance of CCA cells to HSP90 inhibitors by reducing levels of DNAJB5. HSP90 inhibitors might be developed for the treatment of CCA and miRNA21 might be a marker of sensitivity to these agents.

HSP90 Inhibition Drives Degradation of FGFR2 Fusion Proteins

“…Encouragingly, a recent report has hinted that ICC cells are addicted to HSP90 regardless of their mutational landscape. (29) We therefore suggest that the anticancer effects of HSP90 inhibitors in FF-expressing ICCs might integrate suppression of the main oncogenic driver (i.e., FFs themselves), with inhibition of other client/s playing a necessary role in maintaining the ICC transformed phenotype.…”

MiR-30a-5p promotes cholangiocarcinoma cell proliferation through targeting SOCS3

“…The levels of miR-433 and miR-22 were down-regulated in CCA, and restoration of these miRNAs contributed to ciliary restoration and decreased the malignant phenotype of cancer cells by targeting histone deacetylase 6 [9]. Furthermore, miR-21 was highly expressed in CCA and appeared to mediate resistance of CCA cells to HSP90 inhibitors by reducing levels of DNAJB5 [10].…”

“…Recently, increasing researches have revealed that miRNAs were powerful regulators in the tumorigenesis of CCA [9,10]. The levels of miR-433 and miR-22 were down-regulated in CCA, and restoration of these miRNAs contributed to ciliary restoration and decreased the malignant phenotype of cancer cells by targeting histone deacetylase 6 [9].…”

MicroRNAs and cholangiocarcinoma: elucidating the effects of tiny giants

“…Lampis et al . (11) demonstrated that miR-21 targets genes that act as target proteins for HSP90 in human CCA cell lines and inhibition of this miRNA helps reduce CCA progression. Saha et al .…”