Journal of Experimental & Clinical Cancer Research (2017) 36:56
Elevated Gab2 induces tumor growth and angiogenesis in colorectal cancer through upregulating VEGF levels
The human CRC cell lines were obtained from American Type Culture Collection (ATCC, Manassas, VA, USA). SW480 and SW620 cells were cultured in Leibovitz’s L-15 medium (GIBCO Laboratories, Grand Island, NY, USA) supplemented with 10% fetal bovine serum (FBS) (HyClone, Logan, UT, USA), 100 U/ml penicillin and 100μg/ml streptomycin. All the cells were cultured at 37 °C in a humidified air atmosphere containing 5% carbon dioxide. 30 consecutive specimens were collected form CRC patients undergoing surgical resection at Department of Gastrointestinal Surgery, Affiliated Hospital of Zunyi Medical College, between May 2015 and September 2015. None of these patients had received chemo-, radio- or immunotherapy prior to surgery. Informed consent was obtained from all patients before surgery, and our study were approved by the Ethics Committee of Affiliated Hospital of Zunyi Medical College according to the 1975 Declaration.Given the important role of VEGF in tumor growth and angiogenesis, we investigated the expression of VEGF in 15 cases of stage I–II, 15 cases of stage III–IV CRC tissues and 15 normal tissues by immunohistochemistry assay. Compared with the normal tissues, the expression of VEGF was markedly increased in stage I–II CRC tissues (Fig. 1a,
b). Moreover, the levels of VEGF in stage III–IV CRC tissues were obviously higher than that of stage I–II tissues (Fig. 1a,
b). In addition, the expression of Gab2 in the above different colorectal tissues also was detected, and its expression in stage I–II colorectal carcinoma was significantly higher than that of normal ones (Fig. 1a,
c). Similar to VEGF, the expression of Gab2 in stage III–IV colorectal carcinoma was markedly increased than that of stage I–II tissues (Fig. 1a,
c). To investigate the correlation of VEGF with Gab2 expression levels in CRC tissues, we used qRT–PCR to measure the expression levels of VEGF and Gab2 in the above 30 CRC tissues (Fig. 1d). As a result, Gab2 was found to be positively correlated with VEGF levels in CRC tissues (Fig. 1e), which indicated that Gab2 may be involved in the angiogenic process of CRC.We thank the Department of Immunology, Zunyi Medical College, and Immunology Innovation Base of Postgraduate Education in Guizhou Province for providing the experimental platform. In addition, we also thank the Department of Gastrointestinal Surgery, the Affiliated Hospital of Zunyi Medical College for providing CRC sample and clinical data.