Evaluation of the Cytotoxic Effects of a Recombinant form of the Soluble Mutant IL-6 Receptor on an Ovarian Cancer Cell Line.

BACKGROUND

Interleukin-6 (IL-6) plays an important role in cancer metastasis. Therefore, it seems that inhibition of IL-6 may act as an anticancer agent.

OBJECTIVES

This study examined the anti-proliferative and IL-6 signal transduction inhibitory effects of a mutant IL-6 receptor (mIL-6R) on an ovarian cancer cell line.

MATERIALS AND METHODS

The intein1-mIL-6R was expressed in BL21 at various inducer concentrations and temperatures. The expressed protein was purified using the IMPACT system, and the best-examined conditions (i.e., temperature, time, cleavage buffer pH) for intein1auto-cleavage were achieved. The anti-proliferative effects of mIL-6R on OVCAR-3 cancer cells were investigated using MTT assay and RT-PCR to determine its effects on suppressing the JAK-STAT pathway genes.

RESULTS

The highest solubility of 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. Also, mIL-6R diminished the survival of OVCAR-3 cells compared 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

The recombinant mIL-6R showed a strong concentration-dependent anti-proliferative effect on the OVCAR-3 cell line. However, it needs further evaluation for its potential activity against disorders associated with increased IL-6.