Background: IL-6 plays an important role in cancer metastasis. Therefore, it seems that interleukin-6 inhibition can act as an anticancer agent.Objectives: In this study, the anti-proliferative and IL-6 signal transduction inhibitory effects of a mutant IL-6 receptor (mIL-6R), were examined on an ovarian cancer cell line.Methods: The intein1-mIL-6R was expressed in E. coli BL21 at various inducer concentrations and temperatures. The expressed protein was purified using the IMPACT system, and the best examined condition (temperature, time, cleavage buffer pH) for intein1auto-cleavage was achieved. The anti-proliferative effects of mIL-6R on OVCAR-3 cancer cells was investigated using MTT assay and RT-PCR to determine its effects on the suppression of the JAK-STAT pathway genes.Results: The most soluble mIL-6R was obtained at 20 °C, 0.5 mM IPTG. The highest level of intein1 cleavage occurred at 25 °C, 24 hours of incubation, and pH 4 of cleavage buffer. mIL-6R diminished the survival of OVCAR-3 cells in comparison to PBS (p value = 0.024), with 48 hours IC50 of 1.117 μg/mL. Also, mIL-6R significantly reduced the expression of the JAK, STAT, and VEGF genes.Conclusion: mIL-6R can be further evaluated for its potential activity against disorders associated with the increase of IL-6.