André Nayara Delgado, Silva Viviane Aline Oliveira, Watanabe Maria Angelica Ehara, De Lucca Fernando Luiz
Federal University of Sao Joao del‑Rei, 35501296 Divinópolis, MG, Brazil.
Molecular Oncology Research Center, Barretos Cancer Hospital, 14784-400 Barretos, SP, Brazil.
Oncol Rep. 2016 Apr;35(4):2419-24. doi: 10.3892/or.2016.4620. Epub 2016 Feb 12.
The incidence of malignant melanoma has increased greatly in recent decades presenting a high mortality rate despite intensive efforts in this area of research. Recent studies indicate that the chemokine receptor 4 (CXCR4) plays a critical role in cancer. Thus, it has been reported that CXCL12 binding to CXCR4 initiates various downstream signaling pathways that result in a plethora of responses involved in cell proliferation and metastasis. Recently, we demonstrated that CXCR4 silencing by RNA interference (RNAi) significantly reduced the number of pulmonary metastatic nodules. In the present study, we examined the effect of the intratumoral injection of CXCR4 short hairpin (shRNA) expressing plasmids on the growth of B16‑F10 melanoma in mice. In vitro transfection of these tumor cells with CXCR4 shRNA expressing plasmid (CXCR4 shRNA) significantly reduced the levels of CXCR4 mRNA (85%) and CXCR4 protein (70%) compared with the control. We showed that the tumor growth was significantly reduced (66%) in mice inoculated with transfected B16‑F10 melanoma cells when compared with the control group. We also found that the intratumoral injection of CXCR4 shRNA expressing plasmids results in a significant inhibition (70%) of B16‑F10 melanoma growth. This finding supports the hypothesis that a direct administration of RNAi‑based therapeutics into the target tumor is a promising approach for overcoming the hurdles of systemic delivery. The present study is the first demonstration that CXCR4 plays a critical role in B16-F10 melanoma growth. Currently there is great interest in the development of antagonists for therapeutic targeting CXCR4 expression. Considering our results and the fact that CXCR4 is highly conserved between human and mouse, this experimental model of cancer may be useful for the discovery of new CXCR4 antagonists with clinical implications.
近几十年来，恶性黑色素瘤的发病率大幅上升，尽管在该研究领域投入了大量精力，但其死亡率仍很高。最近的研究表明，趋化因子受体4（CXCR4）在癌症中起关键作用。因此，据报道，CXCL12与CXCR4结合会启动各种下游信号通路，从而导致大量参与细胞增殖和转移的反应。最近，我们证明通过RNA干扰（RNAi）使CXCR4沉默可显著减少肺转移瘤结节的数量。在本研究中，我们检测了瘤内注射表达CXCR4短发夹（shRNA）的质粒对小鼠B16-F10黑色素瘤生长的影响。与对照组相比，用表达CXCR4 shRNA的质粒（CXCR4 shRNA）对这些肿瘤细胞进行体外转染可显著降低CXCR4 mRNA水平（85%）和CXCR4蛋白水平（70%）。我们发现，与对照组相比，接种转染后的B16-F10黑色素瘤细胞的小鼠肿瘤生长显著降低（66%）。我们还发现，瘤内注射表达CXCR4 shRNA的质粒可显著抑制（70%）B16-F10黑色素瘤的生长。这一发现支持了以下假设，即直接将基于RNAi的治疗药物注入靶肿瘤是克服全身给药障碍的一种有前景的方法。本研究首次证明CXCR4在B16-F10黑色素瘤生长中起关键作用。目前人们对开发针对CXCR4表达的治疗性拮抗剂非常感兴趣。考虑到我们的研究结果以及CXCR4在人和小鼠之间高度保守这一事实，这种癌症实验模型可能有助于发现具有临床意义的新型CXCR4拮抗剂。
