Antitumor Effect Of G31P, CXCR1/2Antagonist, Combination With Cisplatin In Mice Hepatocellular Carcinoma

Objective: CXC chemokines play an important role in the development ofinflammation, angiogenesis, invasion and metastasis of tumor cells. IL-8, one of CXCchemokines, is involved in chemotactic effect of neutrophils, T cells and otherinflammatory cells by binding to its receptor CXCR1and CXCR2. Role of IL-8wasalso proved in invasion, angiogenesis and metastasis processes of different tumors.G31P，a chemokine receptor CXCR1/2antagonist, can combine with CXCR1/CXCR2with high affinity and block many chemokines which bind with CXCR1and CXCR2receptors, including IL-8, and act as anti-inflammatory and antitumor agent.Cisplatin (DDP), a cytotoxic antitumor drug, is widely used to treat a variety ofsolid tumors. Cisplatin can inhibit the replication of DNA in cancer cells, interfere themetabolism of proteins and damage the structure of cell membrane. The anti-tumoreffect of cisplatin is in dose-dependent manner, but the pursuit of high-dose therapeuticeffect also leads to more serious side effects including kidney toxicity which is the mostserious side effect caused by cisplatin.In this research, we study the antitumor effects of combination therapy of G31Pand DDP on mice liver cancer cells. At the same time, the effects of G31P oncisplatin-induced renal injury were also investigated. This study provides new ideas forthe treatment of cancer in clinical.Methods: In vitro, the effects of G31P and DDP regimen on H22cellsproliferation were investigated by MTT assay. In vivo BALB/c mice were inoculated1×106H22cells subcutaneously. On the7thday after inoculation, mice were randomlydivided into DDP+G31P group, G31P group, DDP group and Control group. Therewere15mice in each group. Mice in G31P group and DDP+G31P group were treated with G31P (500μg/kg of body weight; s.c.) on alternative days, and other groups weretreated with isovolumic saline at the same time. Mice of DDP group and DDP+G31Pgroup were treated with cisplatin (12.5mg/kg; i.p.) once time, and the other groupswere treated with isovolumic saline at the same time. Detection method: On the5thdayafter treatment,5mice of each group were sacrificed and kidney tissues were collected.And then we observed kidney tissue by H&E staining, assayed the activity of MPO anddid RT-PCR to detect inflammatory cytokine in kidney tissues. On9thday of treatment,the remaining mice were sacrificed (n=10). The solid tumors were collected andweighted. And then we did pathological examination of tumor tissues.Immunohistochemistry and western-blot were done to detect tissue-related proteinexpression in tumor tissue.Results:1. MTT assay showed that G31P cannot inhibit the growth of H22cells in vitro.When G31P combined with DDP of low concentration, it can improve the inhibitioneffect on H22cells. While on high concentration of DDP, G31P showed no influence ongrowth inhibition effect on H22cells.2. G31P combined with cisplatin could significantly inhibit tumor growth. Theaverage tumor quality of G31P+DDP group (0.21±0.09g) was significantly less thanControl group (1.06±0.51g)（p<0.01), and also less than the DDP group (0.57±0.21g)（p<0.05)or G31P group (0.56±0.20g)（p<0.05); The inhibition rate of G31P group,DDP group and G31P+DDP group were46.07%±0.19,45.91%±0.19and80.19%±0.08; After administration of drug, the growth of tumor volume of DDP+G31P group was very slow compared with the rest three groups.3. Histopathological Analysis showed that G31P+DDP group has obvious necrosis intumor tissues.4. G31P+DDP can significantly inhibit the expression of EGFR（p<0.01), MMP-2（p<0.01), VEGF（p<0.01) and NF-кB in tumor tissues, which was detected by westernblot and immunohistochemical staining.5. G31P can relieve kidney failure caused by high doses of DDP and improve thesurvival rate of mice.6. The pathology results showed that G31P can reduce renal structural damage causedby DDP.7. Compare with the DDP applied individually group, G31P can reduce neutrophil infiltration in the kidneys, and can reduce the expression of TNF-α（p<0.01) and MIP-2（p<0.01).Conclusion：1. The combination of G31P and DDP can significantly inhibit the growth of mousehepatoma cells and also inhibit the expression of EGFR, VEGF, MMP-2and NF-kB oftumor tissues.2. G31P can mitigate the cisplatin-induced nephrotoxicity and improve survival rateof mice. G31P also reduce the renal pathological damage, infiltration of neutrophils inkidney and expression of TNF-α and MIP-2in renal tissues caused by DDP.