Silencing of the ARK5 gene reverses the drug resistance of multidrug-resistant SGC7901/DDP gastric cancer cells

Evaluation of ARK5 and SIRT3 expression in renal cell carcinoma and their clinical significance

BACKGROUND

Globally Renal Cell Carcinoma (RCC) represents 3% of malignant tumours in adults and 1.78% in Egypt. AMPK-related protein kinase 5 (ARK5) is mainly associated with a hypoxic microenvironment which is a feature of the major RCC subtypes. Additionally, it displays decreased mitochondrial respiration. SIRT3 is a mitochondrial deacetylase that modifies multiple mitochondrial proteins.

MATERIAL AND METHODS

Fifty eight cases of RCC, and 30 non-neoplastic cases (of End-Stage Kidney Disease (ESKD) were subjected to immunohistochemistry by ARK5 and SIRT3. The results of IHC were correlated together and correlated with the available clinicopathologic and survival data.

RESULTS

Although no significant difference was detected between RCC and ESKD groups regarding ARK5 expression, there was a significant association with RCC regarding H-score and nucleocytoplasmic expression (both P = 0.001). Also, SIRT3 was highly expressed in RCC in comparison to the ESKD group (H-score: P = 0.001). There were significant associations between nucleocytoplasmic ARK5 expression and higher tumour grade, low apoptotic and high mitotic indices, tumour extent, advanced tumour stage, and impaired response of tumours to chemotherapeutic drugs (P = 0.039, P = 0.001, P = 0.027, P = 0.011, P = 0.009, and P = 0.014 respectively). Moreover, the H score of ARK5 expression showed significant associations with tumour grade, apoptotic and mitotic indices, tumour extension, tumour stage, and response to therapy (P = 0.01, 0.035, 0.001, 0.004. 0.003 and 0.013). Regarding SIRT3 expression, it showed significant associations with apoptotic and mitotic indices, tumour extent, tumour stage and response to therapy (P = 0.022, 0.02, 0.042, 0.039 and 0.027). Interestingly, there was a highly significant correlation between the expression of ARK5 and SIRT3 (P = 0.009). Univariate survival analysis revealed a significant association between short survival duration and both nucleocytoplasmic expression of ARK5 and positive SIRT3 expression (P = 0.014 and 0.035).

CONCLUSION

ARK5 and SIRT3 are overexpressed in RCC and associated with parameters of poor prognosis as well as short survival. Both seem to influence response to therapy in RCC. So, they could be new targets for therapy that may improve tumour response and patients' survival. There is a postulated relationship that needs more extensive investigation.

Discovery of a novel NUAK1 inhibitor against pancreatic cancer

The novel (nua) kinase family 1 (NUAK1) is an AMPK-related kinase and its expression is associated with tumor malignancy and poor prognosis in several types of cancer, suggesting its potential as a target for cancer therapy. Therefore, the development of NUAK1-targeting inhibitors could improve therapeutic outcomes in cancer. We synthesized KI-301670, a novel NUAK1 inhibitor, and assessed its anticancer effects and mechanism of action in pancreatic cancer. It effectively inhibited pancreatic cancer growth and proliferation, and induced cell cycle arrest, markedly G0/G1 arrest, by increasing the expression of p27 and decreasing expression of p-Rb and E2F1. Additionally, the apoptotic effect of KI-301670 was observed by an increase in cleaved PARP, TUNEL-positive cells, and annexin V cell population, as well as the release of cytochrome c via the loss of mitochondrial membrane potential. KI-301670 inhibited the migration and invasion of pancreatic cancer cells. Mechanistically, KI-301670 effectively inhibited the PI3K/AKT pathway in pancreatic cancer cells. Furthermore, it significantly attenuated tumor growth in a mouse xenograft tumor model. Our results demonstrate that a novel NUAK1 inhibitor, KI-301670, exerts anti-tumor effects by directly suppressing cancer cell growth by affecting the PI3K/AKT pathway, suggesting that it could be a novel therapeutic candidate for pancreatic cancer treatment.