Differential expression of Rab27A/B correlates with clinical outcome in hepatocellular carcinoma

AIM:To investigate the association of Rab27A and Rab27B expression with clinicopathological characteristics and prognosis of hepatocellular carcinoma(HCC).METHODS:We used reverse transcription polymerase chain reaction(RT-PCR),real-time PCR,and Western blotting to detect Rab27A and Rab27B mRNA and protein expression in 5 human HCC lines and the immortalized hepatic HL-7702 cell line.We further examined 148 primary HCC samples matched with adjacent normal tissue and 80 non-HCC specimens by immunohistochemistry to evaluate the correlation of Rab27A and Rab27B expression with clinicopathological features and prognosis.RESULTS:Our data showed that Rab27A and Rab27Bwere differentially expressed in cell lines and primary HCC tumors.Rab27A mRNA and protein were detected in 67%(4/6)of human cell lines and 80%(4/5)of HCC cell lines,while Rab27B was found in 50%(3/6)of human lines and 40%(2/5)of HCC lines.Rab27A expression was higher in primary HCC(46.2%,66/143)than in matched adjacent tissue(24.3%,33/136,P<0.001),whereas immunopositivity for Rab27B was lower in primary HCC(57.4%,81/141)than in matched adjacent tissue(87.5%,119/136,P<0.001).Analysis of clinicopathological characteristics of 148 HCC specimens revealed significant correlations between Rab27A and Rab27B expression and tumor tumor-node-metastasis(TNM)classification(P=0.046 and P=0.027,respectively),and between strong Rab27A expression and tumor differentiation grade(P=0.008).Survival analyses revealed that patients with Rab27A+or Rab27B+tumors had significantly reduced overall survival compared with that of patients with Rab27A-or Rab27B-tumors(P= 0.015 and P=0.005,respectively).Risk analyses revealed that Rab27B+and TNMⅢ-Ⅳwere independent poor prognosis factors associated with a 3.36-and 3.37fold higher relative risk of death,respectively.CONCLUSION:Rab27A and Rab27B expression were closely correlated with tumor progression and can be valuable prognostic indicators for HCC patients.

MAWBP and MAWD inhibit proliferation and invasion in gastric cancer

AIM: To investigate role of putative mitogen-activated protein kinase activator with WD40 repeats (MAWD)/ MAWD binding protein (MAWBP) in gastric cancer (GC). METHODS: MAWBP and MAWD mRNA expression level was examined by real-time reverse transcriptasepolymerase chain reaction and semi-quantitative polymerase chain reaction in six GC cell lines. Western blotting was used to examine the protein expression levels. We developed GC cells that stably overexpressed MAWBP and MAWD, and downregulated expression by RNA interference assay. Proliferation and migration of these GC cells were analyzed by 3-(4,5-dimethyl2-thiazolyl)-2,5-diphenyl tetrazolium bromide (MTT), soft agar, tumorigenicity, migration and transwell assays. The effect of expression of MAWBP and MAWD on transforming growth factor (TGF)-β1-induced epithelialmesenchymal transition (EMT) was examined by transfection of MAWBP and MAWD into GC cells. We detected the levels of EMT markers E-cadherin, N-cadherin and Snail in GC cells overexpressing MAWBP and MAWD by Western blotting. The effect of MAWBP and MAWD on TGF-β signal was detected by analysis of phosphorylation level and nuclear translocation of Smad3 using Western blotting and immunofluorescence. RESULTS: Among the GC cell lines, expression of endogenous MAWBP and MAWD was lowest in SGC7901 cells and highest in BGC823 cells. MAWBP and MAWD were stably overexpressed in SGC7901 cells and knocked down in BGC823 cells. MAWBP and MAWD inhibited GC cell proliferation in vitro and in vivo . MTT assay showed that overexpression of MAWBP and MAWD suppressed growth of SGC7901 cells (P < 0.001), while knockdown of these genes promoted growth of BGC823 cells (P < 0.001). Soft agar colony formation experiments showed that overexpression of MAWBP and MAWD alone or together reduced colony formation compared with vector group in SGC7901 (86.25±8.43, 12.75±4.49, 30±6.41 vs 336.75±22.55, P < 0.001), and knocked-down MAWBP and MAWD demonstrated opposite effects (131.25±16.54, 88.75±11.12, 341.75±22.23 vs 30.25±8.07, P < 0.001). Tumorigenicity experiments revealed that overexpressed MAWBP and MAWD inhibited GC cell proliferation in vivo (P < 0.001). MAWBP and MAWD also inhibited GC cell invasion. Transwell assay showed that the number of traverse cells of MAWBP, MAWD and coexpression group were more than that in vector group (84±16.57, 98.33±9.8, 29±16.39 vs 298±11.86, P < 0.001). Coexpression of MAWBP and MAWD significantly decreased the cells traversing the matrix membrane. Conversely, knocked-down MAWBP and MAWD correspondingly promoted invasion of GC cells (100.67±14.57, 72.66±8.51, 330.67±20.55 vs 27±11.53, P < 0.001). More importantly, coexpression of MAWBP and MAWD promoted EMT. Cells that coexpressed MAWBP and MAWD displayed a pebble-like shape and tight cell-cell adhesion, while vector cells showed a classical mesenchymal phenotype. Western blotting showed that expression of E-cadherin was increased, and expression of N-cadherin and Snail was decreased when cells coexpressed MAWBP and MAWD and were treated with TGF-β1. Nuclear translocation of p-Smad3 was reduced by attenuating its phosphorylation. CONCLUSION: Coexpression of MAWBP and MAWD inhibited EMT, and EMT-aided malignant cell progression was suppressed.

Overexpression of p42.3 promotes cell growth and tumorigenicity in hepatocellular carcinoma

AIM:To investigate the association of p42.3 expression with clinicopathological characteristics and the biological function of p42.3 in human hepatocellular carcinoma(HCC).METHODS:We used reverse transcription-polymerase chain reaction(RT-PCR),quantitative real-time RT-PCR and western blotting to detect p42.3 mRNA and protein expression in hepatic cell lines.We examined primary HCC samples and matched adjacent normal tissue by immunohistochemistry to investigate the correlation between p42.3 expression and clinicopathological features.HepG2 cells were transfected with a pIRES2EGFP-p42.3 expression vector to examine the function of the p42.3 gene.Transfected cells were analyzed for their viability and malignant transformation abilities by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay,colony formation assay,and tumorigenicity assay in nude mice.RESULTS:p42.3 is differentially expressed in primary HCC tumors and cell lines.Approximately 69.6%(96/138) of cells were p42.3-positive in hepatic tumor tissues,while 30.7%(35/114) were p42.3-positive in tumor-adjacent normal tissues.Clinicopathological characteristics of the HCC specimens revealed a significant correlation between p42.3 expression and tumor differentiation(P = 0.031).However,p42.3 positivity was not related to tumor tumor-node-metastasis classification,hepatitis B virus status,or hepatoma type.Regarding p42.3 overexpression in stably transfected HepG2 cells,we discovered significant enhancement of cancer cell growth and colony formation in vitro,and significantly enhanced tumorigenicity in nude mice.Western blot analysis of cell cycle proteins revealed that enhanced p42.3 levels promote upregulation of proliferating cell nuclear antigen,cyclin B1 and mitotic arrest deficient 2.CONCLUSION:p42.3 promotes tumorigenicity and tumor growth in HCC and may be a potential target for future clinical cancer therapeutics.