Promoter hypermethylation of the CFTR gene as a novel diagnostic and prognostic marker of breast cancer.

Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer-related deaths among women. New biomarkers with definite diagnostic and prognostic efficacy are urgently needed. Here, we showed that the promoter of the cystic fibrosis transmembrane conductance regulator (CFTR) was hypermethylated in breast cancer. The messenger RNA level of CFTR was downregulated in breast cancer. Notably, all 19 breast cancer patients with hypermethylated CFTR were diagnosed with invasive carcinoma. Moreover, CFTR was upregulated in decitabine (10 µM) treated breast cancer cells. Overexpression of CFTR inhibited cell growth whereas knockdown of CFTR promoted cell invasion. In the tissue array analysis, the CFTR protein level decreased significantly in breast cancer and low CFTR protein level correlated with poor survival with a P-value of 0.034. Thus, promoter hypermethylation of the CFTR gene might be a novel diagnostic marker of breast cancer.

Identification of the circRNA-miRNA-mRNA regulatory network of Hsp90 inhibitor-induced cell death in colorectal cancer by integrated analysis.

Colorectal cancer (CRC) is a global disease with high incidence and mortality rate. Hsp90 inhibitors induce cell death in various cancers, including CRC. However, the underlying mechanisms need to be clarified further. In this study, Caco-2 cells were treated with 0.25 µM SNX-2112, an Hsp90 inhibitor, for 48 h; subsequently, whole-transcriptome sequencing was performed. At the mRNA level in SNX-2112-treated Caco-2 cells, 1588 genes were upregulated, and 433 genes were downregulated. Six genes were found to be associated with necroptosis and apoptosis, and these 6 upregulated genes were validated by RT-qPCR. Hundred and six miRNAs were upregulated, and 48 miRNAs were downregulated in SNX-2112-treated Caco-2 cells. Eleven downregulated miRNAs were found to interact with the 6 upregulated genes. Moreover, 676 circRNAs were upregulated, and 291 circRNAs were downregulated in SNX-2112-treated Caco-2 cells. Among them, 126 circRNAs were found to be the target of the 11 downregulated miRNAs. The circRNA-miRNA-mRNA regulatory network of Hsp90 inhibitor-induced cell death in colorectal cancer was constructed. This regulatory network extends the underlying mechanism of Hsp90 and improves our understanding of Hsp90 inhibitors as potential targeted therapeutic agents.

JQ1, a BET-bromodomain inhibitor, inhibits human cancer growth and suppresses PD-L1 expression.

Most traditional cytotoxic chemotherapeutic agents have poor aqueous solubility and significant toxicity. Hence, there is a need to develop molecule-targeted drugs. Programmed death-ligand 1 (PD-L1) is associated with the prognosis of several cancer types, and blockade of PD-1/PD-L1 signaling increases the amplitude of anti-tumor immunity. In the present study, we investigated the effects of JQ1, a bromodomain and extraterminal-bromodomain inhibitor, on cell growth, and messenger RNA (mRNA) and protein levels of PD-L1 in renal cell carcinoma primary culture cells, and prostate, liver, and lung cancer cell lines. The results of the cell counting kit-8 assay suggested that JQ1 inhibits cell growth in a dose-dependent manner. The mRNA and protein levels of PD-L1 decreased in the primary culture of JQ1-treated renal carcinoma, prostate cancer, liver cancer, and lung cancer cell lines. In addition, the mRNA level of PD-L2 also decreased in the JQ1-treated cells. Overall, JQ1 might be a potential anti-tumor agent.

CFTR interacts with Hsp90 and regulates the phosphorylation of AKT and ERK1/2 in colorectal cancer cells.

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CF cells and tissues exhibit various mitochondrial abnormalities. However, the underlying molecular mechanisms remain elusive. Here, we examined the mechanisms through which CFTR regulates Bcl-2 family proteins, which in turn regulate permeabilization of the mitochondrial outer membrane. Notably, inhibition of CFTR activated Bax and Bad, but inhibited Bcl-2. Moreover, degradation of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2) and AKT increased significantly in CFTR-knockdown cells. Dysfunction of CFTR decreased heat-shock protein 90 (Hsp90) mRNA levels, and CFTR was found to interact with Hsp90. Inhibition of Hsp90 by SNX-2112 induced the degradation of phosphorylated AKT and ERK1/2 in Caco2 and HRT18 cells. These findings may help provide insights into the physiological role of CFTR in CF-related diseases.

BJ-B11, an Hsp90 Inhibitor, Constrains the Proliferation and Invasion of Breast Cancer Cells.

Breast cancer is the leading cause of cancer-related deaths in women; however, its underlying etiology remains largely unknown. In this study, we systematically analyzed breast cancer tissues using comprehensive iTRAQ labeled quantitative proteomics, identifying 841 differentially expressed proteins (474 and 367 significantly over- and under-expressed, respectively), which were annotated by protein domain analysis. All the heat shock proteins identified were upregulated in breast cancer tissues; Hsp90 upregulation was also validated by RT-qPCR and immunohistochemistry, and high Hsp90 protein levels correlated with poorer survival. Hsp90AA1 overexpression promoted MDA-MB-231 cell proliferation, whilst BJ-B11, an Hsp90 inhibitor, hampered their invasion, migration, and proliferation in a time and dose-dependent manner and induced cell cycle arrest and apoptosis. BJ-B11 inhibited the expression of epithelial-mesenchymal transition (EMT) marker in MDA-MB-231 cells, whereas Hsp90AA1 promoted its expression. Moreover, BJ-B11 inhibited tumor growth in xenograft model. Altogether, Hsp90 activation is a risk factor in breast cancer patients, and BJ-B11 could be used to treat breast cancer.