Linoleic acid pathway disturbance contributing to potential cancerization of intrahepatic bile duct stones into intrahepatic cholangiocarcinoma.

BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) is the second most common primary hepatic malignancy with poor prognosis. Intrahepatic bile duct stone (IBDS) is one of the key causes to ICC occurrence and can increase morbidity rate of ICC about forty times. However, the specific carcinogenesis of IBDS is still far from clarified. Insight into the metabolic phenotype difference between IBDS and ICC can provide potential mechanisms and therapeutic targets, which is expected to inhibit the carcinogenesis of IBDS and improve the prognosis of ICC. METHODS: A total of 34 participants including 25 ICC patients and 9 IBDS patients were recruited. Baseline information inclusive of liver function indicators, tumor biomarkers, surgery condition and constitution parameters etc. from patients were recorded. ICC and IBDS pathological tissues, as well as ICC para-carcinoma tissues, were collected for GC-MS based metabolomics experiments. Multivariate analysis was performed to find differentially expressed metabolites and differentially enriched metabolic pathways. Spearman correlation analysis was then used to construct correlation network between key metabolite and baseline information of patients. RESULTS: The IBDS tissue and para-carcinoma tissue have blurred metabolic phenotypic differences, but both of them essentially distinguished from carcinoma tissue of ICC. Metabolic differences between IBDS and ICC were enriched in linoleic acid metabolism pathway, and the level of 9,12-octadecadienoic acid in IBDS tissues was almost two times higher than in ICC pathological tissues. The correlation between 9,12-octadecadienoic acid level and baseline information of patients demonstrated that 9,12-octadecadienoic acid level in pathological tissue was negative correlation with gamma-glutamyl transpeptidase (GGT) and alkaline phosphatase (ALP) level in peripheral blood. These two indicators were all cancerization marker for hepatic carcinoma and disease characteristic of IBDS. CONCLUSION: Long-term monitoring of metabolites from linoleic acid metabolism pathway and protein indicators of liver function in IBDS patients has important guiding significance for the monitoring of IBDS carcinogenesis. Meanwhile, further insight into the causal relationship between linoleic acid pathway disturbance and changes in liver function can provide important therapeutic targets for both IBDS and ICC.

miR-93 regulates liver tumor initiating cells expansion and predicts chemotherapeutic response of patients.

Tumor initiating cells (T-ICs) play an important role in tumorigenesis, progression, metastasis, recurrence and drug resistance, but the underlying mechanism was not clearly elucidated. In our study, we found that miR-93 was highly expressed in liver T-ICs. Self-renewal and tumorigenesis ability of liver T-ICs were enhanced by miR-93 overexpression and attenuated by miR-93 interference. Mechanically, miR-93 regulated liver T-ICs by binding to 3'-UTR of myotubularin-related protein 3 (MTMR3). In addition, miR-93 was found highly expressed in cisplatin or sorafenib-resistant liver cancer tissues. Interference of miR-93 sensitizes hepatoma cells to cisplatin or sorafenib treatment. Clinical cohort analysis showed that Hepatocellular carcinoma (HCC) patients with low miR-93 were benefit more from TACE or sorafenib treatment. In conclusion, our study demonstrates a new regulation mechanism of liver T-ICs, a new target for HCC, and a biomarker for postoperative TACE or sorafenib.

miR-206 inhibits liver cancer stem cell expansion by regulating EGFR expression.

Liver cancer stem cells (CSCs) are involved in tumorigenesis, progression, drug resistance and recurrence of hepatocellular carcinoma (HCC). However, the underlying mechanism for the propagation of liver cancer stem cells was unclear. Herein, we observed miR-206 expression was reduced in both chemoresistant HCCs and recurrent HCCs from patients. A dramatically decrease of miR-206 was detected in cluster of differentiation 133 (CD133) or epithelial cell adhesion molecule (EpCAM)-positive liver CSCs and in CSC-enriched hepatoma spheres. Functional studies revealed that a forced expression of miR-206 inhibited liver CSCs expansion by suppressing the dedifferentiation of hepatoma cells and attenuating the self-renewal of liver CSCs. Mechanistically, bioinformatic and luciferase reporter analysis identified epidermal growth factor receptor (EGFR) as a direct target of miR-206. Moreover, miR-206 downregulated the expression of EGFR in liver CSCs. There was a significant inverse correlation between miR-206 and EGFR mRNA expression in HCC samples. Special EGFR inhibitor Gefitinib abolished the discrepancy in liver CSC proportion and the self-renewal capacity between miR-206 overexpression hepatoma cells and control cells, which further confirmed that EGFR was required in miR-206-inhibited liver CSCs expansion. Conclusion: miR-206 could suppress HCC cell dedifferentiation and liver CSCs expansion by targeting EGFR signaling.

Circular RNA circVAPA Promotes Cell Proliferation in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the most common malignancy in liver and is one of the leading causes of cancer-induced deaths all over the world. Circular RNAs (circRNAs) have been proven to be related to cancer initiation and progression in mounting reports. However, research on the role of circRNAs in human cancers, including HCC, is still in its infancy. circVAPA has been unmasked as oncogenic in colorectal cancer. Yet the function of circVAPA in HCC has never been elucidated. circVAPA, miR-377-3p, and prosaposin (PSAP) mRNA expression levels were detected by real-time quantitative PCR. PSAP protein levels were measured by Western blot. Cell proliferation was evaluated by CCK-8, colony formation, and EdU assays. Binding capacity was assessed by dual-luciferase reporter assay. circVAPA was upregulated in HCC cell lines and circVAPA depletion was associated with decreased HCC cell proliferation. circVAPA promotes PSAP expression through sequestering miR-377-3p. The suppression of HCC cell proliferation caused by circVAPA silence was revived by PSAP overexpression. This study revealed that circVAPA contributes to HCC cell proliferation through sponging miR-377-3p and thereby disinhibiting PSAP, shedding light on a new insight into HCC initiation and progression.