Shruthi Kanthaje

Hepatocellular carcinoma (HCC) is the most common liver cancer with high mortality rate in patients suffering from liver diseases. The drug of choice used in advanced-stage of HCC is sorafenib. However, adaptive resistance has been observed in HCC patients undergoing long-term sorafenib treatment, lowering its effectiveness. Hence, it is important to overcome drug resistance to improve overall management of HCC. Here, we have identified a candidate biomarker for sorafenib resistance in a HCC model cell line, HepG2. Initially, comparative proteomic profiling of parental HepG2 [HepG2 (P)] and sorafenib-resistant HepG2 [HepG2 (R)] cells was performed via MALDI (matrix-assisted laser desorption/ionization) which revealed the deregulation of vimentin in HepG2 (R) cells. Gene and protein level expression of vimentin was also observed through quantitative real-time polymerase chain reaction (qRT PCR) and fluorescence-activated cell sorting (FACS), respectively. Furthermore, withaferin A was used to study regulation of vimentin expression and its significance in sorafenib resistance. Both gene and protein level of vimentin expression was found to be downregulated in HepG2 (R) in comparison to HepG2 (P). Interestingly, the study demonstrated that withaferin A further lowered the expression of vimentin in HepG2 (R) cells in a dose-dependent manner. Also, inhibition of vimentin lowered ABCG2 expression and decreased cell viability in parental as well as sorafenib resistant HepG2 cells. Hence, our study for the first time highlighted the probable therapeutic potential of vimentin in sorafenib resistant HepG2, a HCC model cell line.

Type 2 diabetes mellitus (T2DM) is a major risk factor associated with hepatocellular carcinoma (HCC). However, the association of T2DM with liver cirrhosis and therapy response in HCC patients is not clear. Hence, in this study, we have evaluated the influence of T2DM on liver cirrhosis severity of HCC and sorafenib response. HCC patients were divided in two groups: T2DM (n = 20) and non-T2DM (nT2DM; n = 50). We found significantly higher number of patients in T2DM group had decompensated liver disease with Child–Turcotte–Pugh score ≥ 7. Additionally, 71.4% patients were observed to be sorafenib sensitive in T2DM group which was significantly higher as compared to 30% in nT2DM group. This study has highlighted the predisposition of HCC patients with T2DM toward more severe liver disease who were found to be better respondents of sorafenib. Impact statement: We have explored the association of type 2 diabetes mellitus (T2DM) on liver cirrhosis severity along with response toward sorafenib in hepatocellular carcinoma (HCC). Most HCC patients exhibit prior history of liver cirrhosis that results following long span of chronic liver disease. T2DM constitutes as an important risk factor for HCC development which is known to elevate its incidence. Further, sorafenib is the FDA approved therapy for HCC whose therapeutic outcome is not investigated in HCC patients with T2DM till date. This observation-based study has unveiled a positive association between T2DM and severity of liver cirrhosis as well as sorafenib response in HCC as examined in a clinical setting.

Hepatocellular carcinoma (HCC) is the primary liver malignancy that contributes towards the second most common cause of cancer‐related mortality. The targeted chemotherapeutic agent, sorafenib, is known to show a statistically significant but limited overall survival advantage in advanced HCC. However, the individual patient response towards sorafenib varies drastically, with most experiencing stable disease and few with partial response; complete response is very rare. Progressive disease despite the treatment is also evident in many patients, indicating drug resistance. These varied responses have been linked with the modulation of several intracellular signaling pathways. Notably, the regulation of these pathways through diverse operating biomolecules, including microRNAs (miRNAs), is the focus of recent studies. MicroRNAs are tiny, non‐coding RNA molecules that regulate the expression of several target genes. In addition, miRNAs are known to play a role in the progression of HCC carcinogenesis. Interestingly, miRNAs have also been identified to play differential roles in terms of sorafenib response in HCC such as biomarkers and functional modulation of cellular response to sorafenib, hence, they are also being therapeutically evaluated. This review outlines the role of reported miRNAs in different aspects of sorafenib response in HCC.

MicroRNA-122 (miR-122) is liver specific and plays an important role in physiology as well as diseases including hepatocellular carcinoma (HCC). Downregulation of miR-122 in HCC modulates apoptosis. Similarly, the putative targets of miR-122, the forkhead box (FOX) family genes also play an important role in the regulation of apoptosis. Hence, an interplay between miR-122 and FOX family genes has been explored in this study. Initially, an augmentation of apoptosis was noticed in HepG2 cells after transfection with miR-122. Further, the predicted miR-122 targets, the FOX family genes ( FOXM1b, FOXP1, and FOXO4) were selected via in silico analysis based on their role in apoptosis. We checked the expression of all these genes at transcript level after the transfection of miR-122 and found that the relative expression of FOXP1 and FOXM1b was significantly downregulated (p < 0.005) and that of FOXO4 was upregulated (p < 0.005). Thus, the finding indicates deregulation of these FOX genes as a result of miR-122 augmentation might be involved in the modulation of apoptosis. Impact Statement: Here, we have investigated the crosstalk between microRNA-122 (miR-122) and selective FOX family genes in HepG2 cells. miR-122 is a prominent miRNA in liver and has been reported to be downregulated in hepatocellular carcinoma (HCC). It has been speculated that diminished level of miR-122 during HCC might be one of the reasons for tumor progression. However, the exact molecular interactions are not clear yet. This study unravels one of the molecular mechanisms of miR-122 through which it might impact the tumorigenesis of HCC.