Secreted GRP78 activates EGFR-SRC-STAT3 signaling and confers the resistance to sorafeinib in HCC cells.

Acquired resistance is a common phenomenon for HCC patients who undergone sorafenib treatment, however the mechanism by which acquired resistance develops remains elusive. In this study, we found that GRP78 could be detected in the serum samples of HCC patients and the conditional medium of multiple HCC cell lines, suggesting that GRP78 is secreted by HCC cells. Further studies showed that secreted GRP78 facilitated the proliferation and inhibited the apoptosis induced by sorafenib both in HCC cell lines and in tumor xenografts. We further found that secreted GRP78 could interact physically with EGFR, therefore activates EGFR signaling pathway. knockdown of EGFR decreased secreted GRP78 induced phosphorylation of SRC and STAT3. By contrast, overexpression of EGFR further enhanced the phosphorylation of SRC and STAT3 induced by secreted GRP78, suggesting the critical role of EGFR in secreted GRP78 conferred resistance to sorafeinib. Moreover, inhibition of SRC by PP2 antagonized the resistance to sorafenib and inhibited the activation of STAT3 conferred by secreted GRP78. Taken together, our results showed that secreted GRP78 could interact with EGFR, activate EGFR-SRC-STAT3 signaling, conferring the resistance to sorafenib.

Human aquaporin 4 gene polymorphisms in Chinese patients with neuromyelitis optica.

OBJECTIVE: To investigate the association between aquaporin 4 (AQP4) gene polymorphisms and Chinese patients with neuromyelitis optica (NMO). METHODS: 122 consecutive anti-AQP4 autoantibody (NMO-IgG) seropositive cases were enrolled for gene sequencing. Furthermore, ten SNPs were selected and genotyped for a case-control association analysis on 208 cases and 204 healthy subjects. RESULTS: 14 novel SNPs were identified, while there were no nonsynonymous mutations and their frequency was low. The heterozygous genotype at two 3' UTR SNPs was significantly higher in cases than controls: the A/T genotype of SNP rs1058424 (54.81% vs. 42.65%, p(adjusted)=0.024, OR=1.670, 95% CI=1.071-2.605) and the C/T genotype of SNP rs3763043 (53.85% vs. 42.65%, p(adjusted)=0.028, OR=1.638, 95% CI=1.054-2.545). Moreover, the 3' UTR haplotype ATATGGAT may be protective for NMO (7.67% vs. 12.18%, p=0.042). CONCLUSIONS: Polymorphisms in the coding region of AQP4 are unlikely to confer NMO susceptibility. However, the 3' UTR of this gene presents several polymorphic sites that may affect NMO risk in the Chinese.

Baicalin attenuates inflammation by inhibiting NF-kappaB activation in cigarette smoke induced inflammatory models.

Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) is a key player in the inflammatory response. Baicalin is an extract from roots of the plant scutellaria baicalensis. Many studies show that baicalin has anti-inflammatory, anti-bacterial and antiviral activities. Here we investigated the influence of baicalin on COPD inflammation and the mechanism of anti-inflammatory effect in vivo and in vitro. In vivo, COPD rat model was established by cigarette smoke (CS) exposure. Thirty-six Sprague-Dawley (SD) rats were randomly assigned to six experimental groups: control, CS, dexamethasone (DXM), and baicalin (20 mg/kg, 40 mg/kg, 80 mg/kg). The lung pathology was observed and leukocytes in bronchoalveolar lavage fluid (BALF) were counted by Optical microscope. Pulmonary function was measured by using an animal plethysmograph. The production of cytokines was measured by ELISA and the expression levels of NF-kappaB p65 protein were detected by immunohistochemistry. The results in vivo show CS exposure significantly increased the expression of IL-8, IL-6 and TNF-alpha in plasma and BALF and enhanced NF-kappaB p65 expression in the lungs. Baicalin treatment markedly attenuated the inflammatory effects of CS. In vitro, cell model was established by using cigarette smoke extract (CSE) to stimulate type II pneumocytes. Type II pneumocytes were also divided into six groups: control, CSE, pyrrolidine dithiocarbamate (PDTC), and baicalin (5 mumol, 10 mumol, 20 mumol). Cytokines levels were measured by ELISA. Expression of IkappaB and p65 phosphorylation was detected by western blotting. NF-kappaB DNA-binding activity was detected by EMSA. The results show that CSE resulted in increasing IL-8, IL-6 and TNF-alpha expression and activation of NF-kappaB. The proinflammatory effects of CSE were inhibited by treatment of baicalin in a dose-dependent manner. It can be concluded that baicalin has significant anti-inflammatory effects on CS induced COPD rat models and CSE-induced cell models, and the effectiveness increases with increasing baicalin dosage. The anti-inflammatory effect is likely achieved by inhibiting the NF-kappaB pathway.