degrasyn and Pancreatic-Neoplasms

Wilm's tumour-1 (WT1) is overexpressed in pancreatic ductal adenocarcinoma (PDAC) and enhances metastasis. Deubiquitination stabilizes target proteins, and inhibiting deubiquitination facilitates the degradation of target proteins. However, whether inhibiting deubiquitination of WT1 facilitates its degradation and presents anti-cancer ability in PDAC is unknown. Here, we found that deubiquitinase inhibitor degrasyn rapidly induced the degradation of endogenous and exogenous WT1 through enhancing ubiquitination of WT1 followed by the up-regulation of E-cadherin. Knockdown of WT1 by short hairpin RNAs (shRNAs) inhibited metastasis and overexpression of WT1 partially prevented degrasyn-induced anti-metastasis activity, suggesting that degrasyn presents anti-metastasis activity partially through degrading WT1 protein. We further identified that USP5 deubiquitinated WT1 and stabilized its expression. The higher expressions of USP5 and WT1 are associated with tumour metastasis. More importantly, degrasyn inhibited the activity of USP5 and overexpression of USP5 partially prevented degrasyn-induced degradation of WT1 protein, suggesting that degrasyn degraded WT1 protein through inhibiting the activity of USP5. Finally, degrasyn reduced the tumorigenicity in a xenograft mouse model and reduced the metastasis in vivo. Our results indicate that degrasyn presents strong anti-cancer activity through USP5-WT1-E-cadherin signalling in PDAC. Therefore, degrasyn holds promise as cancer therapeutic agent in PDAC with high expressions of USP5 and WT1.

Topics: Animals; Antigens, CD; Apoptosis; Biomarkers, Tumor; Cadherins; Carcinoma, Pancreatic Ductal; Cell Proliferation; Cyanoacrylates; Deubiquitinating Enzymes; Endopeptidases; Gene Expression Regulation, Neoplastic; Humans; Mice; Mice, Nude; Neoplasm Invasiveness; Pancreatic Neoplasms; Prognosis; Pyridines; Tumor Cells, Cultured; WT1 Proteins; Xenograft Model Antitumor Assays

Gemcitabine is the cornerstone of pancreatic cancer treatment. Although effective in most patients, development of tumor resistance to gemcitabine can critically limit its efficacy. The mechanisms responsible for this phenomenon remain elusive, but evidence suggests that ubiquitin-specific peptidases (USPs) may be key regulators in cancer chemo-resistance. The present study aimed to investigate the role of USP9X in gemcitabine resistance using in vitro pancreatic cell lines and a mouse xenograft model. We found that the expression of USP9X in pancreatic cancer cells was positively correlated with gemcitabine resistance, and that inhibition of USP9X by WP1130 sensitized pancreatic cancer cells to gemcitabine. Gemcitabine induced autophagy, and blocking autophagy with chloroquine improved sensitivity to gemcitabine. We also found that WP1130 inhibited gemcitabine-induced autophagy, and blocking autophagy abolished the sensitization effect of WP1130 on gemcitabine in pancreatic cancer cells. Finally, combined gemcitabine and WP1130 treatment enhanced the anti-tumor effect of gemcitabine by suppressing autophagy in vivo. Taken together, these results demonstrate that inhibition of USP9X sensitized pancreatic cancer cells to gemcitabine by inhibiting autophagy, which provides a novel insight into gemcitabine resistance in pancreatic cancer.

Topics: Animals; Autophagy; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cyanoacrylates; Deoxycytidine; Drug Resistance, Neoplasm; Enzyme Inhibitors; Gemcitabine; Humans; Mice, Inbred BALB C; Mice, Nude; Pancreatic Neoplasms; Pyridines; Ubiquitin Thiolesterase; Xenograft Model Antitumor Assays

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and deadly malignancies. Recently, the deubiquitinating protease USP9X has been shown to behave as an oncogene in a number of neoplasms, including those of breast, brain, colon, esophagus and lung, as well as KRAS wild-type PDAC. However, other studies suggest that USP9X may function as a tumor-suppressor in a murine PDAC model when USP9X expression is depleted during early pancreatic development. To address the conflicting findings surrounding the role of USP9X in PDAC, we examined the effects of knocking down USP9X in five human PDAC cell lines (BxPC3, Capan1, CD18, Hs766T, and S2-013). We demonstrate that knocking down USP9X in each of the PDAC cell lines reduces their anchorage-dependent growth. Using an inducible shRNA system to knock down USP9X in both BxPC3 and Capan1 cells, we also determined that USP9X is necessary for the anchorage-independent growth. In addition, knockdown of USP9X alters the cell cycle profile of BxPC3 cells and increases their invasive capacity. Finally, we show that an inhibitor of deubiquitinating proteases, WP1130, induces significant cytotoxicity in each of the five PDAC cell lines tested. Overall, our work and the work of others indicate that the function and role of USP9X is highly context-dependent. Although USP9X may function as a tumor-suppressor during the establishment of PDAC, data presented here argue that USP9X promotes cell growth in advanced PDAC cells when PDAC is typically diagnosed. Hence, USP9X may be a promising therapeutic target for the treatment of advanced PDAC.

Topics: Carcinoma, Pancreatic Ductal; Cell Line, Tumor; Cell Proliferation; Cyanoacrylates; Humans; Neoplasm Invasiveness; Nitriles; Pancreatic Neoplasms; Protease Inhibitors; Pyridines; Repressor Proteins; Ubiquitin Thiolesterase; Ubiquitin-Protein Ligases; Ubiquitination