CXCR4 promotes gefitinib resistance of Huh7 cells by activating the c‐Met signaling pathway

C‐X‐C chemokine receptor type 4 (CXCR4) expression is associated with poor prognosis of hepatocellular carcinoma (HCC). The aim of this study was to explore the biological role of CXCR4 in gefitinib resistance of HCC. Compared with a normal, non‐gefitinib‐resistant, human HCC cell line (Huh7), CXCR4 mRNA and protein were highly expressed in gefitinib‐resistant Huh7 cells (Huh7‐R). Cell proliferation was decreased, and apoptosis was enhanced in Huh7 cells in the presence of gefitinib. These influences conferred by gefitinib treatment on proliferation and apoptosis of Huh7 cells were abolished by CXCR4 overexpression. CXCR4 knockdown reduced the proliferation ability of HuH‐7R cells after gefitinib treatment. Importantly, CXCR4 overexpression had no influence on caveolin 1 (Cav‐1) expression; similarly, Cav‐1 silencing did not cause a substantive change in CXCR4 expression. However, CXCR4 activated Cav‐1, c‐Met, and Raf‐1 in Huh7 cells, whereas Cav‐1 silencing repressed the expression of Raf‐1 and phosphorylated c‐Met in Huh7 cells. CXCR4 overexpression promoted proliferation and repressed apoptosis in gefitinib‐treated Huh7 cells, which was partly rescued by PHA‐665752 (a c‐Met inhibitor) treatment or c‐Met deficiency. Finally, we constructed a tumor xenograft model to determine the influence of CXCR4 overexpression on tumor growth of HCC. CXCR4 overexpression accelerated tumor growth of HCC, which was abrogated by c‐Met deficiency. These findings demonstrate that CXCR4 overexpression activates c‐Met via the Cav‐1 signaling pathway, thereby promoting gefitinib resistance of Huh7 cells. Thus, this study highlights novel insights into the mechanism of gefitinib resistance of HCC and CXCR4 may become a potential target for HCC treatment

Study on the Mechanism of Targeted Poly(lactic-co-glycolic acid) Nano-Delivery Carriers in the Treatment of Hemangiomas

Hemangiomas, also called infantile hemangiomas (IH), are the most common congenital benign vascular tumors in infants and young children. At present, there are many treatment methods for proliferative hemangiomas, which have different effects and lack predictability. Propranolol has gradually replaced glucocorticoids as the first-line treatment for infants and young children with hemangiomas. However, premature discontinuation is prone to relapse, and the efficacy and safety of medication need to be further studied and determined. The exact pathogenesis of hemangiomas is still unclear. Therefore, in this study, poly(lactic-co-glycolic acid) (PLGA) nanoparticles were used as drug delivery carriers, propranolol was encapsulated, and PLGA-propranolol (PLGA-PP) nanodelivery preparations were prepared and targeted. Anisotropy and pharmacokinetics were preliminary studied. At the same time, after the treatment of HemECs cells with PLGA-PP in gradient concentration in vitro, CCK-8 method was used to detect the cell proliferation, and Anyixin-V/PI double staining method was used to detect the apoptosis rate of cells. The effect of PLGA-PP nano-delivery vector on hemangioma was studied by western blot method to detect the expression level of Id-1 protein in HemECs. The results showed that after PLGA-PP treated HemECs for 24 h, PLGA-PP significantly inhibited HeECs proliferation and promoted their apoptosis, and the intracellular Id-1 protein expression was also reduced. Therefore, this study believes that the mechanism of PLGA-PP nano-targeted delivery preparations in the treatment of hemangiomas is achieved by down-regulating the Id-1 gene, thereby inhibiting the colonization of HemECs and promoting its apoptosis effect.</jats:p