Angiostatin up-regulation in gastric cancer cell SGC7901 inhibits tumorigenesis in nude mice

Angiogenesis of gastrointestinal tumours and their metastases – a target for intervention?

Angiogenesis is an obligatory event for the growth of tumours beyond 2 mm in diameter, above which simple oxygen diffusion can no longer support the rapid proliferation of malignant cells. Angiogenesis is a fine balance between inhibitory and stimulatory factors, the knowledge of which offers novel targets for the treatment of gastrointestinal neoplasia. A literature search of Pubmed and Medline databases was undertaken, using the keywords colorectal cancer, pancreatic cancer, gastrointestinal cancer, angiogenesis and anti-angiogenesis therapy. It was found that angiogenesis in primary tumours is a sequential and highly complex cascade of molecular events resulting in the rapid exponential growth of the tumour. Hepatic metastases of primary tumours may be less reliant on traditional angiogenic pathways, by co-opting pre-existing hepatic vasculature. Research into angiogenesis has revealed many different sites that can be targeted by agents such as tyrosine kinase inhibitors. Many anti-angiogenic agents are undergoing preclinical evaluation, with only a few entering phase I and phase III clinical trials. However, early results suggest that anti-angiogenic therapy could be an important adjunct to conventional chemotherapy treatment of gastrointestinal neoplasia.

Therapeutic effect of endostatin-vascular endothelial growth inhibitor recombinant adenoviruses on gastric carcinoma in nude mice

AIM

To investigate the effects of recombinant adenoviruses carrying the endostatin-VEGI151 fusion gene AIerapy on gastric carcinoma in nude mice.

METHODS

Human gastric carcinoma SGC7901 cells (5×10⁶) were injected sc into the dorsal midline of nude mice (3 weeks old), and 500 μL (10¹² TCID₅₀/L) of recombinant adenoviruses AdCA13-hENDO-VEGI₁₅₁ or AdLacZ was given respectively sc every other day for ten times. Twenty-four hours after the last injection, tumor size, inhibition rate, expression of target gene, proliferating cell nuclear antigen label index (PCNA LI), apoptotic index (AI), and intratumoral microvessel density (MVD) were evaluated respectively after the mice were sacrificed.

RESULTS

Compared with the control group AdLacZ (2 356±1 140 mm³), the average tumor size of group AdCA13-hENDO-VEGI₁₅₁ was reduced in size(328156 mm³, F =12.42, P =0.0125) with an inhibition rate of 86.1%. The adenoviruses carriyring the target gene could be expressed in gastric carcinoma. The PCNA LI of the treated mice (0.13±0.09%) was lower than the contol (1.400.53%, F =22.30, P =0.0 033). The AI was higher in the treated mice (5.09±0.25%) than in the control (0.61±0.67%, F =155.13, P =0.0 001). The MVD was lower in the treated mice (0.06±0.03% ) than in the control (1.09±0.76%, F =7.38, P =0.0 348).

CONCLUSION

The recombinant adenovirus carrying fusion gene of hENDO-VEGI₁₅₁ can express the fuion protein in gastric carcinoma in nude mice and inhibit the tumor growth.

Expression of estrogen inducing gene PS2/TFF1 in gastric cancer and precancerous lesions

AIM

To determine the significance of PS2/TFF1 protein expression in chronic superficial gastritis (CSG), gastric ulcer (GU),gastric mucosal intestinal metaplasia (IM), gastric mucosal dysplasia and gastric cancer(GC).

METHODS

Pathologic specimens of 121 patients with gastric mucosal diseases and 20 healthy volunteers were immunostained for PS2/TFF1.

RESULTS

Positive PS2/TFF1 staining was seen throughout all epithelia with normal gastric mucosas, CSG, GU and in complete type of intestinal metaplasia (20/21). On the contrary, 11 of 20 incomplete type of intestinal metaplasia had positive staining (P <0.01). The expressions of PS2/TFF1 protein in CSG and GU were significantly higher than that in control group (P <0.01), while the expressions of PS2/TFF1 protein in IM,gastric mucosal dysplasia and GC were obviously lower than that in control group (P <0.01).

CONCLUSION

Our results indicate that PS2/TFF1 may play an important role in gastric mucosal protection,and loss of PS2/TFF1 expression may occur as an early event in the malignant transformation process of intestinal-type tumors.