No abstract

Background and Aims The proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a key role in cholesterol homeostasis, and its inhibition represents an effective therapy to lower low‐density lipoprotein cholesterol (LDL‐C) levels. In this study, we examined the impact of the PCSK9 rs11591147 loss‐of‐function (LOF) variant on liver damage in a multicenter collection of patients at risk of nonalcoholic steatohepatitis (NASH), in clinical samples and experimental models. Methods We considered 1874 consecutive individuals at risk of NASH as determined by histology. The SNP rs11591147, encoding for the p.R46L variant of PCSK9, was genotyped by TaqMan assays. We also evaluated 1) PCSK9 mRNA hepatic expression in human liver, and 2) the impact of a NASH‐inducing diet in mice with hepatic overexpression of human PCSK9. Results Carriers of PCSK9 rs11591147 had lower circulating LDL‐C levels and were protected against nonalcoholic fatty liver disease (NAFLD) (OR: 0.42; 95% CI: 0.22‐0.81; P = .01), NASH (OR: 0.48; 95% CI: 0.26‐0.87; P = .01) and more severe fibrosis (OR: 0.55; 95% CI: 0.32‐0.94; P = .03) independently of clinical, metabolic and genetic confounding factors. PCSK9 hepatic expression was directly correlated with liver steatosis (P = .03). Finally, liver‐specific overexpression of human PCSK9 in male mice drives NAFLD and fibrosis upon a dietary challenge. Conclusions In individuals at risk of NASH, PCSK9 was induced with hepatic fat accumulation and PCSK9 rs11591147 LOF variant was protective against liver steatosis, NASH and fibrosis, suggesting that PCSK9 inhibition may be a new therapeutic strategy to treat NASH.

Designed multiple ligands (DMLs), developed to modulate simultaneously a number of selected targets involved in etiopathogenetic mechanisms of a multifactorial disease, such as diabetes mellitus (DM), are considered a promising alternative to combinations of drugs, when monotherapy results to be unsatisfactory. In this work, compounds 1-17 were synthesized and in vitro evaluated as DMLs directed to aldose reductase (AR) and protein tyrosine phosphatase 1B (PTP1B), two key enzymes involved in different events which are critical for the onset and progression of type 2 DM and related pathologies. Out of the tested 4thiazolidinone derivatives, compounds 12 and 16, which exhibited potent AR inhibitory effects along with interesting inhibition of PTP1B, can be assumed as lead compounds to further optimize and balance the dual inhibitory profile. Moreover, several structural portions were identified as features that could be useful to achieve simultaneous inhibition of both human AR and PTP1B through binding to non-catalytic regions of both target enzymes.

Tumor resistance to apoptosis is one the main causes of anticancer treatment failure. Previous studies showed that LMW‐PTP overexpression enhances resistance of cancer cells to traditional anticancer drugs. Today, the role of LMW‐PTP in inducing resistance to apoptosis in melanoma cells remains to be elucidated. Experimental setting include MTT assay, Annexin V/Pi method, and colony assay to assess whether silencing of LMW‐PTP improves the sensitivity of A375 to dacarbazine, 5‐FU, and radiotherapy. Pharmacological targeting of LMW‐PTP was obtained using Morin, a LMW‐PTP inhibitor. The ability of Morin to improve the effectiveness of anticancer drugs and radiotherapy was also studied. Moreover, PC3 cells were used as an alternative cellular model to confirm the data obtained with melanoma cells. We found that LMW‐PTP silencing improves the effectiveness of dacarbazine, 5‐FU, and radiotherapy. Identical results were obtained in vivo when Morin was used to target LMW‐PTP. We demonstrated that Morin synergizes with dacarbazine, improving its cytotoxic activity. However, we showed that the combined treatment, Morin‐anticancer drug, does not affect the viability of noncancerous cells. Knockdown of LMW‐PTP sensitizes also PC3 cells to docetaxel and radiotherapy. In conclusion, we showed that LMW‐PTP targeting improves effectiveness of anticancer drugs used for treatment of melanoma. Moreover, our results suggest that Morin could be used as adjuvant to improve the outcome of patients affected by metastatic melanoma.

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