ObjectiveLRPPRC is a newly discovered N6-methyladenosine (m6A) modification reader, which potentially affects hepatocellular carcinoma (HCC) progression. PD-L1 in tumor cells is essential for tumor immune evasion. This work investigated the LRPPRC-mediated m6A-modification effect on PD-L1 mRNA and immune escape in HCC.MethodsExpression and clinical implication of LRPPRC and PD-L1 were measured in human HCC cohorts. The influence of LRPPRC on malignant behaviors of HCC cells was investigated through in vitro assays and xenograft tumor murine models. The posttranscriptional mechanism of LRPPRC on PD-L1 and anti-tumor immunity was elucidated in HCC cells via RIP, MeRIP−qPCR, RNA stability, immunohistochemical staining, and so forth.ResultsLRPPRC exhibited the notable upregulated in human HCC tissues, which was in relation to advanced stage and worse overall survival and disease-free survival. Impaired proliferative capacity and G2/M phage arrest were found in LRPPRC-knockout cells, with increased apoptotic level, and attenuated migratory and invasive abilities. In HCC patients and murine models, LRPPRC presented a positive interaction with PD-L1, with negative associations with CD8+, and CD4+ T-cell infiltrations and chemokines CXCL9, and CXCL10. LRPPRC loss downregulated the expression of PD-L1 and its m6A level in HCC cells. Moreover, LRPPRC suppression mitigated tumor growth in murine models and improved anti-tumor immunity and immune infiltration in tumors.ConclusionThis work unveiled that LRPPRC may posttranscriptionally upregulate PD-L1 partially with an m6A-dependent manner for heightening mRNA stabilization of PD-L1 and provided a new mechanism for m6A regulator-mediated immunosuppression in HCC.

Background: Hepatocellular carcinoma (HCC) is one of the most malignant tumors. The in vitro experiments on the application of Anhydroicaritin (AHI), the active ingredient of Bushen Huayu Decoction, in HCC treatment remain limited, particularly regarding its molecular mechanism. Methods: The TCMSP platform was used for drug ingredient screening. The GeneCards database and DisGeNET database are used to collect liver cancer targets. PPI network construction of active component-target intersection target was completed with string database. The GO and KEGG pathway analyses were performed via bioinformatics analysis. The molecular docking was used to confirm AHI’s target proteins. The in vitro experiments were performed to validate the effect of AHI on HCC cell and explore the molecular mechanism by western blotting analysis. Results: Through the intersection, 155 intersection targets are finally obtained. The top 15 active ingredients were quercetin, kaempferol, beta-sitosterol, luteolin, beta-carotene, Stigmasterol, naringenin, formononetin, baicalein, Anhydroicaritin, isorhamnetin, licochalcone, 7-O-methylisomucronulatol, aloe-emodin and 8-O-Methylreyusi. The molecular mocking analysis showed that the four active components (quercetin, kaempferol, luteolin and AHI) and targets had a good binding activity (affinity ≤ 5 kcal/mol). In vitro experiments reveled that AHI could suppress tumor proliferation, invasion and metastasis of HCC cells. Further analysis showed that AHI inhibited tumor growth by PI3K/AKT signal pathway in HCC. Conclusions: The Bushen Huayu Decoction and its active ingredient AHI could fight HCC. The potential mechanism may be associated with inhibiting the activation of PI3K/AKT signal pathway, which may serve as a potential treatment for HCC therapy.

Objective: Cellular senescence is an effective barrier against tumorigenesis. Hence, it is of significance to characterize key features of cellular senescence and the induction of senescence in hepatocellular carcinoma (HCC) cells via pharmacological interventions. Our study determined the biological roles as well as mechanisms of angiotensin II type I receptor (AGTR1) on cellular senescence in HCC.Methods: Lentivirus vector-mediated overexpression or knockdown of AGTR1 was conducted in HCC cells, respectively. A volume of 8 μM sorafenib was used to induce cellular senescence, and ERK was activated by 30 ng/ml ERK agonist EGF. Proliferation was evaluated via clone formation assay. HCC cell senescence was examined by flow cytometry for cell cycle, senescence-associated β-galactosidase (SA-β-gal) staining, and senescence-associated heterochromatin foci (SAHF) analysis. AGTR1, p53, p21, extracellular signal-regulated kinase (ERK), and p-ERK expression were assessed through Western blot or immunofluorescence.Results: AGTR1-knockout HCC cells displayed the attenuated proliferative capacity, G2-M phase arrest, increased expression of p53 and p21, and elevated percentages of SA-β-gal- and SAHF-positive cells. In sorafenib-exposed HCC cells, overexpressed AGTR1 enhanced the proliferative capacity and alleviated G2-M phase arrest as well as decreased p53 and p21 expression and the proportions of SA-β-gal- and SAHF-positive cells. Moreover, AGTR1 knockdown attenuated the activity of p-ERK in HCC cells, and ERK agonist ameliorated AGTR1 knockdown-induced cellular senescence.Conclusion: This study demonstrates that suppression of AGTR1 induces cellular senescence in HCC through inactivating ERK signaling. The significant synergistic effect of AGTR1 suppression and sorafenib might represent a potential combination therapy for HCC.