The roles and mechanism of chemokine receptor type 5 in colorectal cancer proliferation

Abstract

Objective To examine the expression of chemokine receptor type 5 (CXCR5) in colorectal cancer (CRC) and to explore its relationship with clinicopathological features and cell proliferation in CRC. Methods Immunohistochemical staining method was used to detect the protein expression of CXCR5 in 132 paired specimens of CRC, adjacent and 62 samples of adenoma. Analysing the relationship between CXCR5 with clinicopathological features in CRC. RNA interference (RNAi) technique was applied to construct four CXCR5 short hairpin RNA (shRNA) expression vectors. Lipofectamine 2000 was used to transfer plasmids into colon cancer cell lines LoVo and HCT116. Real-time PCR and Western blotting were used to observe the inhibitory effect of RNAi on CXCR5 expression. Lentivirus production and transduction were used to construct CXCR5 shRNA stably expressed CRC cell lines. CXCR5 overexpressed plasmid was used to construct CXCR5 stably expressed CRC cell lines. cell counting kit-8 (CCK-8) assay and colony formation assay were used to detect the influence of specific CXCR5 on CRC cell. Tumor formation in nude mouse was performed to detect the effects of CXCR5 on the proliferation ability of CRC cells in vivo. FCM were used to detect the cell cycle. Results CXCR5 protein was expressed in 46.97% (62/132) of CRC tissues and 24.19% (15/62) of adenoma tissues, respectively. The protein expression of CXCR5 was negative in adjacent tissues. The protein expression level of CXCR5 in CRC tissues was significantly higher than ademona tissues (P=0.020). The expression of CXCR5 was correlated with relapse, TNM stage, lymph node metastasis and distant metastasis (P=0.004, 0.025, 0.002, 0.008). CCK-8 and colony formation results showed that the CXCR5 shRNA inhibited the proliferation of CRC significantly, whereas overexpression of CXCR5 promoted CRC proliferation in vitro. Tumor formation results in nude mouse showed that CXCR5 silencing inhibited the proliferation and metastasis ability of CRC cells, whereas overexpression of CXCR5 promoted proliferation of CRC cells in vivo. CXCR5 may influence CRC cells proliferation through cell cycle in vitro. Conclusion CXCR5 may play a crucial role in carcinogenesis, development of CRC. CXCR5 could promote proliferation of colon cancer cell both in vitro and in vivo, and may influence CRC development through cell cycle. Key words: Colorectal cancer; Chemokine receptor type 5; Proliferation