IL-6 upregulates the expression of IL-6R through the JAK2/STAT3 signalling pathway to promote progression of hepatocellular carcinoma.

The progression of hepatocellular carcinoma (HCC) involves multifactor, multistep interactions. High expression of interleukin-6 receptor (IL-6R) plays an important role in the occurrence and development of tumours, but the regulatory mechanism of IL-6R expression and its function in HCC have not been fully defined. Western blot was used to evaluate the phosphorylation of key kinases in the JAK2/STAT3 pathway and the protein expression levels of related proliferation molecules, migration molecules and apoptotic molecules. The antiapoptosis, migration and proliferation of cells of each group were analysed with JC-1 to judge the cell apoptosis rate, the EdU method to determine the proliferation vitality of the cells, clone formation experiments and Transwell experiments. High expression of IL-6R in cell lines, lower protein levels of the apoptotic molecules c-Caspase7 and c-Caspase3 and higher protein levels of the proliferative molecules p-P70S6K and migration molecules MMP9 and MMP2 were consistent with stronger antiapoptosis, proliferation and migration. Interestingly, IL-6 upregulated the expression of IL-6R by activating the JAK2/STAT3 signalling pathway. Also, the expression of IL-6R protein was downregulated after lentivirus knockdown of STAT3. In nude mice bearing subcutaneous tumours, upregulation of IL-6R expression after activation of the JAK2/STAT3 signalling pathway by IL-6 significantly increased tumour growth. Moreover, the expression of IL-6R protein was downregulated, and the terminal tumour volume was significantly downregulated in the lentiviral STAT3 knockdown group. IL-6 regulated the transcription of IL-6R through the activation of the JAK2/STAT3 signalling pathway.

Nanoparticles Loaded with GSK1059615 Combined with Sorafenib Inhibited Programmed Cell Death 1 Ligand 1 Expression by Negatively Regulating the PI3K/Akt/NF-κB Pathway, Thereby Reversing the Drug Resistance of Hepatocellular Carcinoma to Sorafenib.

Activation of the cellular signaling pathways can induce sorafenib-resistant hepatocellular carcinoma (HCCR). In this work, the PI3K/mTOR inhibitor GSK1059615 inhibited the proliferation and invasion of HCCR cells. PLGA-PEG-mal diblock copolymer was used to load GSK1059615 and sorafenib, and the vector was further modified with GPC3 antibody (hGC33) to obtain hGC33-modified GSK1059615 and sorafenib-loaded nanoparticles (Ab-G/S-NP). Ab-G/S-NP regulated the activation of cellular signaling pathways in HCCR cells by inhibiting the expression and activation of NF-κB and downregulating the level of programmed cell death 1 ligand 1(PD-L1) to reverse drug resistance of HCCR cells to sorafenib. These findings deserve further study in the combined treatment of HCCR cells with GSK1059615 in vivo to develop a more effective treatment of sorafenib-resistant cancers.

The effects of coal dust exposure on DNA damage and repair of human bronchial epithelial cells.

To explore the effects of coal dust exposure on DNA damage and repair, human bronchial epithelial BEAS-2B cells were exposed to coal dust and the cellular response was investigated. It was found that γ-H2AX foci of DNA damage appeared, γ-H2AX protein level increased, and the rate of cell apoptosis was significantly elevated when BEAS-2B cells were exposed to coal dust for a short time. Phagocytized coal dust particles, swollen mitochondria, and reduced mitochondrial membrane potential were simultaneously identified. Moreover, Caspase-9, Caspase-3, and DFF45 proteins of the mitochondrial apoptotic pathway were activated. After the cells were exposed to coal dust chronically, phosphorylation levels of DNA repair kinases (ATM/ATR, DNA-PKcs) and downstream regulatory protein AKT were significantly upregulated. γ-H2AX foci and tail DNA of the cells following treatment with cisplatin were also reduced, and the colony formation rate was improved. It was concluded that coal dust could induce DNA damage, cause mitochondrial depolarization, and activate mitochondrial apoptosis pathways in BEAS-2B cells. Additionally, activated DNA repair kinases (ATM/ATR and DNA-PKcs) and their regulatory protein AKT increased DNA repair and proliferation of BEAS-2B cells chronically exposed to coal dust.

c-Met up-regulates the expression of PD-L1 through MAPK/NF-κBp65 pathway.

Sorafenib acquired drug resistance during the treatment of hepatocellular carcinoma (HCC) reduces the efficacy of the drug. The immune escape effect induced by PD-L1 is largely associated with drug resistance of HCC. However, the regulated mechanism of PD-L1 is unclear. This research aimed to clarify the control mechanism of PD-L1. c-Met was found abnormally highly expressed in Huh-7SR with high PD-L1 expression. In addition, c-Met, as the upstream target molecule of PD-L1, promoted the proliferation and migration of HCC in vitro and in vivo. We also found that c-Met activated the MAPK signaling pathway and the downstream NF-κBp65 transcription factor, which interacts with the proximal region of the PD-L1 promoter to promote PD-L1 expression. In conclusion, c-Met regulates the transcription of PD-L1 through the MAPK/NF-κBp65 pathway, thereby promoting the progress of HCC. The role of c-Met and PD-L1 in HCC needs to be further studied, but it is a potential target for the treatment of HCC. KEY MESSAGES: In the study, it was found that c-Met is also abnormally highly expressed in Huh-7SR with high PD-L1 expression and can promote the development of HCC in vitro and in vivo. PD-L1 and c-Met expression levels are positively correlated. In the follow-up mechanism study, we found that c-Met activated the MAPK signaling pathway and subsequently activated the downstream NF-κBp65 transcription factor, which interacts with the proximal region of the PD-L1 promoter to promote PD-L1 expression. Our study found that c-Met regulates the transcription of PD-L1 through the MAPK/NF-κBp65 pathway, thereby promoting the progress of HCC.

Curcumin reverses hepatic epithelial mesenchymal transition induced by trichloroethylene by inhibiting IL-6R/STAT3.

OBJECTIVE: Epithelial mesenchymal transition (EMT) and inflammation have been identified as carcinogenic agents. This study aims to investigate whether inhibition of trichloroethylene (TCE) associated hepatocellular carcinoma (HCC) by curcumin is associated with inflammation and EMT. METHODS: In the current study, TCE sub-chronic cell model was induced in vitro, and the effects of TCE on cell proliferation, migration, invasion, and expression of functional proteins were verified by Western blot, MTT, clone formation, wound healing, Transwell. The detoxification effect of curcumin on TCE was explored by a mouse tumor-bearing experiment. RESULTS: TCE induces hepatocyte migration, colony formation, and EMT in vitro. In vivo studies have shown that curcumin significantly reduces the mortality of mice and control the occurrence and size of liver tumors by inhibiting the IL-6/STAT3 signaling pathway. In vitro, curcumin inhibits the proliferation of HepG2 cells as determined by MTT assay. In addition, curcumin significantly inhibited the protein expression of IL-6R, STAT3, snail, survivin, and cyclin D1 in THLE-2 and HepG2 cells induced by IL-6. CONCLUSION: Curcumin has anti-inflammatory and anti-proliferative effects, and inhibits the development of HCC induced by TCE by reversing IL-6/STAT3 mediated EMT.

Development of chemiluminescence method based on serum type I collagen hydroxyl terminal peptide ß special sequence (ß-CTX).

The objective of this work is to develop and verify the analytical performance of a chemiluminescence immunoassay for the specific sequence ß-carboxy-terminal cross-linking telopeptide of type I collagen (ß-CTX) in human serum. Two specific monoclonal antibodies (mAb-8A03 and mAb-3D12) with high affinity for ß-CTX were selected, and, under optimized conditions, a chemiluminescence immunoassay method (CLIA) for ß-CTX was established. The CLIA of ß-CTX detected ß-CTX in a wide range of 2.0-6000 ng/L. The recovery rate in serum is 95-105%, the specificity is high, and the cross-reaction rate with common easily interfering substances is low (not more than 0.01%). The CLIA correlates well with Roche electrochemiluminescence immunoassay (ECLIA), with a correlation coefficient of 0.9551, which fully meets the requirements of clinical analysis. The developed ß-CTX CLIA kit has high sensitivity and good stability. It has the same performance as the commercial Roche ECLIA kit and can be applied clinically.

LY­294002 enhances the chemosensitivity of liver cancer to oxaliplatin by blocking the PI3K/AKT/HIF­1α pathway.

Liver cancer remains one of the leading causes of cancer deaths worldwide. The therapeutic effect of oxaliplatin on liver cancer is often limited by acquired resistance of the cancer cells. Abnormal activation of the PI3K/AKT pathway plays an important role in the acquired resistance of oxaliplatin. The present study investigated the effects of the PI3K inhibitor LY­294002 and AKT inhibitor MK2206 on the chemosensitivity of oxaliplatin­resistant liver cancer cells and the molecular mechanism involved. An oxaliplatin­resistant liver cancer cell line HepG2R was developed. MTT assay, clone formation experiments, flow cytometry and Annexin V­FITC/PI staining were used to determine the proliferation, cycle and apoptosis of HepG2R cells when oxaliplatin was combined with LY­294002 or MK2206 treatment. The effects of LY­294002 and MK­2206 on the abnormal activation of PI3K/AKT pathway and hypoxia inducible factor (HIF)­1α protein level in HepG2R cells were detected using western blotting. The results indicated that the PI3K/AKT pathway is stably activated in HepG2R cells. Compared with the AKT inhibitor MK2206, the PI3K inhibitor LY­294002 more effectively downregulated the phosphorylation levels of p85, p110α, p110ß, p110γ and AKT in the PI3K/AKT pathway in HepG2R cells, and more effectively inhibited the proliferation of the cells. LY­294002 enhanced the chemotherapy sensitivity of HepG2R cells to oxaliplatin by inducing G0/G1 phase arrest and increasing the proportion of apoptotic cells. In addition, LY­294002 reduced the level of HIF­1α, which is highly expressed in HepG2R cells. It was concluded that LY­294002 enhanced the chemosensitivity of liver cancer cells to oxaliplatin by inhibiting the PI3K/AKT signaling pathway, which may be related to the inhibition of HIF­1α expression. These findings may have clinical significance for the treatment of oxaliplatin­resistant liver cancer.

BEZ235 Increases the Sensitivity of Hepatocellular Carcinoma to Sorafenib by Inhibiting PI3K/AKT/mTOR and Inducing Autophagy.

Acquired resistance of hepatocellular carcinoma (HCC) to sorafenib (SFB) is the main reason for the failure of SFB treatment of the cancer. Abnormal activation of the PI3K/AKT/mTOR pathway is important in the acquired resistance of SFB. Therefore, we investigated whether BEZ235 (BEZ) could reverse acquired sorafenib resistance by targeting the PI3K/mTOR pathway. A sorafenib-resistant HCC cell line Huh7R was established. MTT assay, clone formation assay, flow cytometry, and immunofluorescence were used to analyze the effects of BEZ235 alone or combined with sorafenib on cell proliferation, cell cycle, apoptosis, and autophagy of Huh7 and Huh7R cells. The antitumor effect was evaluated in animal models of Huh7R xenografts in vivo. Western blot was used to detect protein levels of the PI3K/AKT/mTOR pathway and related effector molecules. In vitro results showed that the Huh7R had a stronger proliferation ability and antiapoptosis effect than did Huh7, and sorafenib had no inhibitory effect on Huh7R. SFB + BEZ inhibited the activation of the PI3K/AKT/mTOR pathway caused by sorafenib. Moreover, SFB + BEZ inhibited the proliferation and cloning ability, blocked the cell cycle in the G0/G1 phase, and promoted apoptosis in the two cell lines. The autophagy level in Huh7R cells was higher than in Huh7 cells, and BEZ or SFB + BEZ further promoted autophagy in the two cell lines. In vivo, SFB + BEZ inhibited tumor growth by inducing apoptosis and autophagy. We concluded that BEZ235 enhanced the sensitivity of sorafenib through suppressing the PI3K/AKT/mTOR pathway and inducing autophagy. These observations may provide the experimental basis for sorafenib combined with BEZ235 in trial treatment of HCC.

LY3214996 relieves acquired resistance to sorafenib in hepatocellular carcinoma cells.

Background: Sorafenib, an oral multi-kinase inhibitor of rapidly accelerated fibrosarcoma; vascular endothelial growth factor receptor-2/3, platelet-derived growth factor receptor, c-Kit, and Flt-3 signaling, is approved for treatment of advanced hepatocellular carcinoma (HCC). However, the benefit of sorafenib is often diminished because of acquired resistance through the reactivation of ERK signaling in sorafenib-resistant HCC cells. In this work, we investigated whether adding LY3214996, a selective ERK1/2 inhibitor, to sorafenib would increase the anti-tumor effectiveness of sorafenib to HCC cells. Methods: The Huh7 cell line was used as a cell model for treatment with sorafenib, LY3214996, and their combination. Phosphorylation of the key kinases in the Ras/Raf/MAPK and PI3K/Akt pathways, protein expression of the cell cycle, and apoptosis migration were assessed with western blot. MTT and colony-formation assays were used to evaluate cell proliferation. Wound-healing assay was used to assess cell migration. Cell cycle and apoptosis analyses were conducted with flow cytometry. Results: LY3214996 decreased phosphorylation of the Ras/Raf/MAPK and PI3K/Akt pathways, including p-c-Raf, p-P90RSK, p-S6K and p-eIF4EBP1 activated by sorafenib, despite increased p-ERK1/2 levels. LY3214996 increased the anti-proliferation, anti-migration, cell-cycle progression, and pro-apoptotic effects of sorafenib on Huh7R cells. Conclusions: Reactivation of ERK1/2 appears to be a molecular mechanism of acquired resistance of HCC to sorafenib. LY3214996 combined with sorafenib enhanced the anti-tumor effects of sorafenib in HCC. These findings form a theoretical basis for trial of LY3214996 combined with sorafenib as second-line treatment of sorafenib-resistant in advanced HCC.

Targeted Delivery of Glypican 3 (GPC3) Antibody-Modified MicroRNA (miR let-7b-5p) Polymer Nanoparticles to Sorafenib-Resistant Hepatsocellular Carcinoma Cells.

The miR let-7b-5p (a kind of microRNAs) has many pathophysiological regulation effects, including human hepatocellular carcinoma (HCC) pathogenesis. This study investigated whether nanoparticle-mediated miR let-7b-5p could jointly enhance the therapeutic effect of sorafenib on HCC by inhibiting the proliferation of HCC cells, inducing apoptosis, and reversing drug resistance. We evaluated the level of miR let-7b-5p in sorafenib-resistant HepG2 cells (HepG2R) and HepG2 HCC cells by qRT-PCR and analyzed the biological effects of hepatocellular carcinoma treated with sorafenib with miR let-7b-5p, and further studied the toxicity of nanoparticles (Ab-miR-NPs) that deliver miR let-7b-5p mimics and target GPC3 on the surface of hepatocellular carcinoma cells. Results showed that, in HepG2 cells, the expression level of miR let-7b-5p was significantly higher than that in HepG2R cells. Targeted nanoparticle Ab-miR-NPs mediated the delivery of miR let-7b-5p to the HCC cytoplasm and released miRNA after being broken down, down-regulating the expression of IGF1R and inhibiting AKT/mTOR and Ras/Raf signal transmission. Ab-miR-NPs not only enhanced the proliferation of sorafenib in cultured HepG2R cells and induced cell apoptosis efficiency, but they also improved the anti-tumor activity in the mouse models. These results indicated that GPC3 antibody-modified PLGA-PLL (polylactic acid-glycolic acetic copolymer grafted hyper-branched polylysine) loaded miR let-7b-5p polymer nanoparticles combined with sorafenib may be a new treatment strategy for HCC resistant to sorafenib.

hGC33-Modified and Sorafenib-Loaded Nanoparticles have a Synergistic Anti-Hepatoma Effect by Inhibiting Wnt Signaling Pathway.

Delivery of tumor-specific inhibitors is a challenge in cancer treatment. Antibody-modified nanoparticles can deliver their loaded drugs to tumor cells that overexpress specific tumor-associated antigens. Here, we constructed sorafenib-loaded polyethylene glycol-b-PLGA polymer nanoparticles modified with antibody hGC33 to glypican-3 (GPC3 +), a membrane protein overexpressed in hepatocellular carcinoma. We found that hGC33-modified NPs (hGC33-SFB-NP) targeted GPC3+ hepatocellular carcinoma (HCC) cells by specifically binding to GPC3 on the surface of HCC cells, inhibited Wnt-induced signal transduction, and inhibited HCC cells in G0/1 by down-regulating cyclin D1 expression, thus attenuating HCC cell migration by inhibiting epithelial-mesenchymal transition. hGC33-SFB-NP inhibited the migration, cycle progression, and proliferation of HCC cells by inhibiting the Ras/Raf/MAPK pathway and the Wnt pathway in tandem with GPC3 molecules, respectively. hGC33-SFB-NP inhibited the growth of liver cancer in vivo and improved the survival rate of tumor-bearing mice. We conclude that hGC33 increases the targeting of SFB-NP to HCC cells. hGC33-SFB-NP synergistically inhibits the progression of HCC by blocking the Wnt pathway and the Ras/Raf/MAPK pathway.

Anti-GPC3 Antibody-Conjugated BEZ235 Loaded Polymeric Nanoparticles (Ab-BEZ235-NP) Enhances Radiosensitivity in Hepatocellular Carcinoma Cells by Inhibition of DNA Double-Strand Break Repair.

AIM: To assess AB-BEZ235-NP potential as a radio-sensitizer in hepatocellular carcinoma models. METHOD: By comparing hepatocellular carcinoma cell with simple radiation or combined AB-BEZ235-NP therapy, the HCC apoptosis and self-repair level have significant differences in mortality rates and cell migration abilities. RESULTS: Cell proliferation and DNA damage increased by pretreatment with AB-BEZ235-NP after irradiation; further studies on the repair pathway indicated that AB-BEZ235-NP inhibited the important pathway of DSB repair. Our results further show that AB-BEZ235-NP significantly inhibits the phosphorylation of the canonical protein, γ-H2AX, in the NHEJ DSB repair pathway and Serine Protein Kinase (SPK) ATM, and TP53-Binding Protein one. More importantly, AB-BEZ235-NP increased the mount of mean γ-H2AX Foci in irradiated cells, indicating that AB-BEZ235-NP can selectively inhibit DSB repair in HCC cells. Therefore, these results clearly eludicate that treatment with AB-BEZ235-NP is a potential promising therapy which can increase the radiosensitivity to HCC.

Gefitinib sensitization of cisplatin-resistant wild-type EGFR non-small cell lung cancer cells.

PURPOSE: The usual first-line strategy of wild-type EGFR (wtEGFR) non-small cell lung cancer (NSCLC) remains cisplatin-based chemotherapy. However, cisplatin often loses effectiveness because most tumors acquire drug resistance over time. As EGFR is the most important pro-survival/proliferation signal receptor in NSCLC cells, we aimed at investigating whether cisplatin resistance is related to EGFR activation and further evaluating the combined effects of cisplatin/gefitinib (EGFR-tyrosine kinase inhibitor, EGFR-TKI) on cisplatin-resistant wtEGFR NSCLC cells. MATERIALS AND METHODS: EGFR activation was analysed in parental and cisplatin-resistant wtEGFR NSCLC cell lines (H358 and H358R, A549 and A549R). Cellular proliferation and apoptosis of H358R/A549R cells treated with cisplatin or gefitinib, alone or in combination were investigated, and the related effector protein was detected by western blot analysis. Anti-tumor effect of two drugs combined was evaluated in animal models of H358R xenografts in vivo. RESULTS: EGFR was significantly phosphorylated in cisplatin-resistant wtEGFR NSCLC cells H358R and A549R than their parental cells. In H358R and A549R cells, anti-proliferative ability of gefitinib was further improved, and gefitinib combined with cisplatin enhanced inhibition of cellular survive/proliferation, and promotion of apoptosis in vitro. The combined effects were also associated with the inhibition of EGFR downstream effector proteins. Similarly, in vivo, gefitinib and cisplatin in combination significantly inhibited tumor growth of H358R xenografts. CONCLUSION: Abnormal activation of EGFR may induce wtEGFR NSCLC cell resistance to cisplatin. The combined effects of cisplatin/gefitinib suggest that gefitinib, as a combination therapy for patients with cisplatin-resistant wtEGFR NSCLC should be considered.

The PI3K/mTOR dual inhibitor BEZ235 nanoparticles improve radiosensitization of hepatoma cells through apoptosis and regulation DNA repair pathway.

Polymer materials encapsulating drugs have broad prospects for drug delivery. We evaluated the effectiveness of polyethylene glycol-poly (lactic-co-glycolic acid) (PLGA-PEG) encapsulation and release characteristics of PI3K/mTOR inhibitor NVP-BEZ235 (BEZ235). We proposed a strategy for targeting radiosensitization of liver cancer cells. The biocompatibility, cell interaction, and internalization of Glypican-3 (GPC3) antibody-modified, BEZ235-loaded PLGA-PEG nanoparticles (NP-BEZ235-Ab) in hepatoma cells in vitro were studied. Also, the cell killing effect of NP-BEZ235-Ab combined with γ-ray cell was evaluated. We used confocal microscopy to monitor nanoparticle-cell interactions and cellular uptake, conducted focus-formation experiments to analyze the synergistic biological effects of NP-BEZ235-Ab and priming, and studied synergy in liver cancer cells using molecular biological methods such as western blotting. We found that PLGA-PEG has good loading efficiency for BEZ235 and high selectivity to GPC3-positive HepG2 liver cancer cells, thus documenting that NP-BEZ235-Ab acts as a small-molecule drug delivery nanocarrier. At the nominal concentration, the NP-BEZ235-Ab nanoformulation synergistically kills liver cancer cells with significantly higher efficiency than does the free drug. Thus, NP-BEZ235-Ab is a potential radiosensitizer.

Increased efficacy of gefitinib on cisplatin-resistant wild-type epidermal growth factor receptor non-small cell lung cancer cells.

BACKGROUND: Gefitinib is a first-generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) that has become first-line treatment for patients with mutant EGFR non-small cell lung cancer (NSCLC). Despite its anti-tumor activity, the benefit of gefitinib in patients with wild-type EGFR NSCLC is debated. This work aimed to evaluate the effects of gefitinib on cisplatin-resistant wild-type EGFR NSCLC cells in in vitro and in vivo animal xenografts. METHODS: We established a cisplatin-resistant wild-type EGFR NSCLC cell line, H358R, to evaluate the cells' sensitivity to gefitinib compared with that of parental cell line H358. We first tested the p-EGFR of gefitinib's target in H358R and H358 cell line by western blot and immunofluorescence. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), clone formation assay, flow cytometry and annexin V-fluorescein/propidium iodide staining were used to investigate cellular proliferation and apoptosis of H358R/H358 cells treated with gefitinib, and the anti-tumor effect was evaluated in female BALB/c nude mice models of xenografts in vivo. RESULTS: EGFR and the downstream node molecules ERK and AKT were significantly more phosphorylated in H358R than in the parental cells and were inhibited by gefitinib. In H358R cells, gefitinib increased the inhibition of cell survival/proliferation, and the promotion of apoptosis in vitro. The increased anti-tumor effect was present also in H358R xenografts in vivo. CONCLUSIONS: Abnormal activation of EGFR in H358R cells results in enhanced sensitivity to gefitinib. The improved efficacy of gefitinib on cisplatin-resistant wild-type EGFR NSCLC cells suggests that gefitinib as sequential therapy for patients with cisplatin-resistant wild-type EGFR NSCLC should be considered.

BEZ235 increases sorafenib inhibition of hepatocellular carcinoma cells by suppressing the PI3K/AKT/mTOR pathway.

BACKGROUND: Sorafenib is an oral multi-kinase inhibitor that inhibits hepatocellular carcinoma (HCC) via the Ras/Raf/MAPK pathway. However, sorafenib loses effectiveness because most tumors acquire drug resistance over time. As the PI3K/AKT/mTOR signaling pathway is also activated abnormally in HCC, we evaluated the effect of sorafenib, in combination with a dual PI3K/mTOR inhibitor, BEZ235, on HCC cell proliferation and survival in vitro. MATERIALS AND METHODS: Biological phenotypes were analysed in HCC cell lines, parental and sorafenib-resistant HepG2 cells (HepG2 and HepG2R), treated with sorafenib or BEZ235, alone or in combination. HCC cellular proliferation and apoptosis were investigated, and perturbations of the Ras/Raf/MAPK and PI3K/AKT/mTOR signaling/survival pathways were evaluated by western blot analysis. RESULTS: BEZ235 enhanced sorafenib inhibition of cellular proliferation, migration, and promotion of apoptosis in HepG2 and HepG2R cells. The combined effects were associated with inhibition of phosphorylation of AKT, mTOR and S6K in the PI3K/AKT/mTOR pathway, whereas the combination of sorafenib and BEZ235 did not significantly alter the Ras/Raf/MAPK pathway compared with the effect of sorafenib alone. CONCLUSION: Sorafenib/BEZ235 combination has potent anti-HCC cell activity. This anti-tumor activity is most likely multi-factorial, mainly involving PI3K down-regulation and AKT, mTOR and S6K dephosphorylation. Combined inhibition of PI3K/AKT/mTOR and Ras/Raf/MAPK pathways enhances sorafenib inhibition of HCC. The results of these in vitro studies suggest that trials of combined sorafenib and BEZ235 in the treatment of HCC should be considered.

PKI-587 enhances chemosensitivity of oxaliplatin in hepatocellular carcinoma through suppressing DNA damage repair pathway (NHEJ and HR) and PI3K/AKT/mTOR pathway.

Oxaliplatin resistance limits its effectiveness in the treatment of hepatocellular carcinoma (HCC). Abnormal activation of the PI3K/AKT/mTOR pathway has been associated with decreased survival of HCC patients, anti-apoptosis after chemotherapeutic drug-induced DNA damage, and chemoresistance. In this research, we evaluated the effect of the dual PI3K/mTOR inhibitor, PKI-587, on the sensitivity of oxaliplatin in HCC. Two HCC cell lines (HepG2 and SK-Hep1) were used to analyze PKI-587 for DNA damage response, cell proliferation, clonogenic survival, cell cycle and apoptosis after oxaliplatin treatment. A HepG2 tumor-bearing model was used to assess the in vivo effects of the combination of the two compounds. In HCC cells, oxaliplatin stably activated the PI3K/AKT/mTOR pathway, including up-regulation of p-Akt (Ser473), p-mTOR (Ser2448), p-mTOR (Ser2481), p-elF4EBP1, and p-S6K1, and activated the DNA damage repair pathways (non-homologous end joining (NHEJ) and homologous recombination (HR)), up-regulation of p-DNAPKcs (Ser2056), p-ATM (Ser1981), and p-ATR (Ser428), which were attenuated by PKI-587. Compared with oxaliplatin alone, the combination of PKI-587 and oxaliplatin increased the number of γ-H2AX/cells, decreased proliferation of cells, and an increased the percentage of G0/G1 phase cells and apoptotic cells. In vivo, the combination of oxaliplatin with PKI-587 inhibited tumor growth. Anti-tumor effects were associated with induction of mitochondrial apoptosis and inhibition of phosphorylation of mTOR, Akt and γ-H2AX. We conclude that PKI-587 enhances chemosensitivity of oxaliplatin in HCC through suppressing the PI3K/AKT/mTOR signalling pathway and inhibiting the DNA damage repair pathway. The combination of PKI-587 and oxaliplatin appears to be a promising regimen for the treatment of HCC.

BEZ235 enhances chemosensitivity of paclitaxel in hepatocellular carcinoma through inhibiting the PI3K/Akt/mTOR pathway.

Desensitization of hepatocellular carcinoma (HCC) to paclitaxel chemotherapy is a major deterrent to successful treatment of the cancer. Abnormal activation of the PI3K/Akt/mTOR, pathway is a common outcome of chemotherapy for HCC. Therefore, we investigated whether BEZ235, a dual PI3K and mTOR inhibitor, could increase the sensitivity of HCC to paclitaxel. In vitro results showed that paclitaxel, combined with BEZ235, inhibited HCC cell proliferation and migration, arrested the cell cycle in the G2/M phase, and promoted cell apoptosis by decreasing PI3K/Akt/mTOR activity. In vivo experiments confirmed that BEZ235 enhances the anti-tumor effect of paclitaxel by reducing PI3K/Akt/mTOR activity. Immunohistochemical staining showed that paclitaxel combined with BEZ235 reduced the numbers of Ki-67- and GPC3-positive HepG2 cells in tumor tissues. We conclude that BEZ235 enhanced the sensitivity of HCC to paclitaxel, and inhibition of PI3K/Akt/mTOR signaling might be a therapeutic strategy against paclitaxel-resistant HCC.