Alterations and Co-Occurrence of C-MYC, N-MYC, and L-MYC Expression are Related to Clinical Outcomes in Various Cancers.

Background and Objectives: MYC, also known as an oncogenic reprogramming factor, is a multifunctional transcription factor that maintains induced pluripotent stem cells (iPSCs). Although MYC is frequently upregulated in various cancers and is correlated with a poor prognosis, MYC is downregulated and correlated with a good prognosis in lung adenocarcinoma. MYC and two other MYC family genes, MYCN and MYCL, have similar structures and could contribute to tumorigenic conversion both in vitro and in vivo. Methods and Results: We systematically investigated whether MYC family genes act as prognostic factors in various human cancers. We first evaluated alterations in the expression of MYC family genes in various cancers using the Oncomine and The Cancer Genome Atlas (TCGA) database and their mutation and copy number alterations using the TCGA database with cBioPortal. Then, we investigated the association between the expression of MYC family genes and the prognosis of cancer patients using various prognosis databases. Multivariate analysis also confirmed that co-expression of MYC/MYCL/MYCN was significantly associated with the prognosis of lung, gastric, liver, and breast cancers. Conclusions: Taken together, our results demonstrate that the MYC family can function not only as an oncogene but also as a tumor suppressor gene in various cancers, which could be used to develop a novel approach to cancer treatment.

Anti-oncogenic effects of dutasteride, a dual 5-alpha reductase inhibitor and a drug for benign prostate hyperplasia, in bladder cancer.

BACKGROUND: The incidence of bladder cancer (BCa) is approximately four times higher in men than in women. To develop effective BCa treatments, there is an urgent need to understand the differences in the BCa control mechanisms based on gender. Our recent clinical study showed that androgen suppression therapy using 5α-reductase inhibitors and androgen deprivation therapy affects BCa progression, but the underlying mechanisms are still unknown. METHODS: mRNA expression levels of the androgen receptor (AR) and SLC39A9 (membrane AR) in T24 and J82 BCa cells were evaluated by reverse transcription-PCR (RT-PCR). The effect of dutasteride, a 5α-reductase inhibitor, in BCa progression was determined in cells transfected with control and AR-overexpressing plasmids. In addition, cell viability and migration assays, RT-PCR, and western blot analysis were performed to analyze the effect of dutasteride on BCa in the presence of testosterone. Finally, steroidal 5α-reductase 1 (SRD5A1), one of the dutasteride target genes, was silenced in T24 and J82 BCa cells using control and shRNA-containing plasmids, and the oncogenic role of SRD5A1 was evaluated. RESULTS: Dutasteride treatment led to significant inhibition of the testosterone-induced increase dependent on AR and SLC39A9 in cell viability and migration of T24 and J82 BCa cells and induced alterations in the expression level of cancer progression proteins, such as metalloproteases, p21, BCL-2, NF-KB, and WNT in AR-negative BCa. Furthermore, the bioinformatic analysis showed that mRNA expression levels of SRD5A1 were significantly higher in BCa tissues than in normal paired tissues. A positive correlation between SRD5A1 expression and poor patient survival was observed in patients with BCa. Also, Dutasteride treatment reduced cell proliferation and migration via blocking the SRD5A1 in BCa. CONCLUSIONS: Dutasteride inhibited testosterone-induced BCa progression dependent on SLC39A9 in AR-negative BCa and repressed oncogenic signaling pathways, including those of metalloproteases, p21, BCL-2, NF-KB, and WNT. Our results also suggest that SRD5A1 plays a pro-oncogenic role in BCa. This work provides potential therapeutic targets for the treatment of BCa.

TTYH3 Modulates Bladder Cancer Proliferation and Metastasis via FGFR1/H-Ras/A-Raf/MEK/ERK Pathway.

Tweety family member 3 (TTYH3) is a calcium-activated chloride channel with a non-pore-forming structure that controls cell volume and signal transduction. We investigated the role of TTYH3 as a cancer-promoting factor in bladder cancer. The mRNA expression of TTYH3 in bladder cancer patients was investigated using various bioinformatics databases. The results demonstrated that the increasingly greater expression of TTYH3 increasingly worsened the prognosis of patients with bladder cancer. TTYH3 knockdown bladder cancer cell lines were constructed by their various cancer properties measured. TTYH3 knockdown significantly reduced cell proliferation and sphere formation. Cell migration and invasion were also significantly reduced in knockdown bladder cancer cells, compared to normal bladder cancer cells. The knockdown of TTYH3 led to the downregulation of H-Ras/A-Raf/MEK/ERK signaling by inhibiting fibroblast growth factor receptor 1 (FGFR1) phosphorylation. This signaling pathway also attenuated the expression of c-Jun and c-Fos. The findings implicate TTYH3 as a potential factor regulating the properties of bladder cancer and as a therapeutic target.