Coupling the near-infrared fluorescent dye IR-780 with cabazitaxel makes renal cell carcinoma chemotherapy possible

Renal cell carcinoma (RCC) has always been considered resistant to chemotherapy. IR-780 is a near-infrared fluorescent (NIRF) dye that can be efficiently taken up by RCC cells. Cabazitaxel is a cytotoxic drug that interferes with mitosis by acting on tubulin. We chemically fused IR-780 and cabazitaxel into a new drug, Caba-780, which is expected to increase the sensitivity of RCC to chemotherapy. Infrared spectrum, nuclear magnetic resonance spectra, high-resolution mass spectra, and IR spectra were used for detecting structural characterization of the new synthetic drug Caba-780. The RCC cells lines ACHN and 786-O, as well as the non-cancerous human embryonic kidney cell line HEK293, were used to assess the cytotoxicity and tumor-efficient uptake of Caba-780 in vitro. The xenograft tumor-bearing mice and C57 mice were used to estimate the tumor-efficient imaging of Caba-780 as well as the safety and efficacy of its anti-tumor effects in vivo. The new synthetic drug Caba-780 retains the NIRF properties of IR-780. In vitro, Caba-780 was efficiently absorbed by the RCC cell lines ACHN and 786-O, and had an inhibitory effect on their growth, clonogenicity migration, and invasion. At the same time, Caba-780 retained the anti-tumor effect of cabazitaxel, which can inhibit the growth of tumor cells and promote apoptosis by inhibiting mitosis. In vivo experiments showed that Caba-780 can be taken up and imaged in tumor tissue, whereby it inhibits tumor growth. The novel fused molecule Caba-780 has application prospects in the diagnosis and treatment of RCC and makes RCC chemotherapy possible.