Cross-linked hyaluronan gel inhibits the growth and metastasis of ovarian carcinoma

Abstract

Background: The recurrence, metastasis and poor prognosis are important characteristics of ovarian carcinoma (OC), which are associated with exfoliation of cells from the primary tumor and colonization of the cells in pelvic cavity. On the other hand, the life quality of the patients undergoing surgical resection of OC was influenced by postoperative adhesions. Therefore, preventing postoperative implant tumor and adhesion may be effective methods to improve OC treatment. HyaRegen Gel, a cross-linked hyaluronan gel (CHAG), has been widely used as an anti-adhesive agent following pelvic operation in clinic. However, whether it can affect the implantation and growth of OC cells or not is still not clear.

Methods: Migration and invasion assays were applied to detect the effect of CHAG on migration and invasion of OC cells. Western blotting was performed to detect the phosphorylation/activation of EGFR and ERK, and the expression of PCNA and MMP7. Pull down assay was used to analyze the effect of CHAG on the activation of small G protein Rac1. Nude mice implantation tumor model was applied to observe the effect of CHAG on implantation tumor of OC cells.

Results: The results of in vitro experiments showed that CHAG suppressed both basic and EGF-induced migration and invasion of OC cells, blocked the activation of EGF-initiated EGFR activation, inhibited downstream signal transduction of EGFR, and decreased expression of proliferation and migration/invasion related proteins. Meanwhile, results of in vivo experiments showed that CHAG not only inhibited the formation of implantation tumor of OC cells but also delayed the of the growth of the tumors.

Conclusions: CHAG inhibited migration, invasion and proliferation of OC cells in vitro, and suppressed development of implantation tumor of OC in vivo. This made it as both anti-tumor and anti-adhesion agents.

Keywords: Growth; HyaRegen gel; Invasion; Migration; Ovarian carcinoma.

Fig. 1

CHAG inhibits EGF-induced migration and invasion activities of ovarian cancer cells. a-d Migration activity of A2780 and SKOV3 cells. e-h Invasion activity of A2780 and SKOV3 cells. a, c, e and g were representative photomicrographs of cells stained by Giemsa (200×). b, d, f and h represent the folds of cells’ migration or invasion in the corresponding groups. Data are showed as means ± SD from 3 independent experiments. (*P < 0.05, **P < 0.01, compared with control group; ^##P < 0.01, compared with EGF group)

Fig. 2

CHAG inhibits growth of ovarian cancer cell in pelvic cavity. a and c The tumors from the control and CHAG groups were shown. b and d The weight of the tumors in corresponding group. The data were shown as means ± SD. (*P < 0.05, compared with control group)

Fig. 3

CHAG blocks activation of EGFR and its downstream signaling molecules, and inhibits EGF-induced expression of MMPs and PCNA in OC cells. a and b CHAG inhibited phosphorylation/activation of EGFR, Akt and ERK in A2780 and SKOV3 cells. The cells were cultured in serum free DMEM overnight and treated with 500 or 1000 μg/mL CHAG solutions for 1 h and then treated with 100 ng/ml EGF for 5 min. The cellular lysates were subjected to Western blotting. c and d Detection of the expression of MMP7 in A2780 and SKOV3 cells by Western blotting. In EGF group, the cells were treated with 100 ng/ml EGF for 24 h. In the CHAG + EGF groups, the cells were treated with 500 or 1000 μg/mL CHAG and 100 ng/mL EGF for 24 h. The cells were harvested and the lysates were subjected to Western blotting with anti-MMP7 antibodies. e and f Western blotting detection of the expression of PCNA in A2780 and SKOV3 cells. The cells were treated same as described in panel c and d. g and h CHAG blocked the activation of Rac1. The pull-down results were representatives of three independent experiments