These pathways include metabolic, ECM-receptor interactions, tight junctions, biosynthesis of unsaturated fatty acids, ubiquitin mediated proteolysis pathways etc

These pathways include metabolic, ECM-receptor interactions, tight junctions, biosynthesis of unsaturated fatty acids, ubiquitin mediated proteolysis pathways etc. and rapamycin has been used before, the effect of mono-treatment of Nimotuzumab, rapamycin and combination therapy in human glioma expressing different types of EGFR is not well-studied. Herein, we evaluated the efficacy of dual blockage using monoclonal antibody against EGFR (Nimotuzumab) and an mTOR inhibitor (rapamycin) in Caucasian patient-derived human glioma cell lines, Asian patient-derived human glioma cell lines, primary glioma cells derived from the Mayo GBM xenografts, and primary short-term glioma culture derived from high-grade glioma patients. Methods The combination effect of Nimotuzumab and rapamycin was examined in a series of primary human glioma cell lines and glioma cell lines. The cell viability was compared to TMZ treatment alone. Endogenous expressions of EGFR in various GBM cells were determined Irosustat by western blotting. Results The results showed that combination of Nimotuzumab with rapamycin significantly enhanced the therapeutic efficacy of human glioma cells compared to single treatment. More importantly, many of the Asian patient-derived glioma cell lines and primary cells derived from Singaporean high-grade gliomas, which showed resistance to TMZ, were susceptible to the combined treatments. Conclusions In conclusion, our results strongly suggest that combination usage of Nimotuzumab and rapamycin exert higher cytotoxic activities than TMZ. Our data suggest that this combination may provide an alternative treatment for Irosustat TMZ-resistant gliomas regardless of the EGFR status. [21]. Further, tumors derived from combination treatment were compared with mono-therapies using microarray analysis. Combination treatment resulted in the downregulation of genes beyond the typical pathways associated with Nimotuzumab and rapamycin. These pathways include metabolic, ECM-receptor interactions, tight junctions, biosynthesis of unsaturated fatty acids, ubiquitin mediated proteolysis pathways etc. Although this study differs from ours in many ways including experimental objectives, concentration of drugs and presence of EGF ligands and different cancer types, it is nevertheless encouraging that this combination treatment is effective given different cancer model. This is especially relevant in GBM because it highlights the plausibility of targeting TMZ resistant and EGFR-null glioma cells with alternative combination drugs such as Nimotuzumab and rapamycin. Furthermore, Nimotuzumab has recently been shown to enhance cancer radiosensitivity by inhibiting DNA-PKcs activation via the blockage of the PI3K/AKT pathway [46]. Although we have yet to determine whether the radiosensitizing effect of Nimotuzumab may be further enhanced with rapamycin, our results have nevertheless indicated that this combination of Nimotuzumab and rapamycin is usually more efficacious compared to TMZ and single treatment although it warrants further studies to delineate the underlying mechanism of action given different EGFR receptor status and possible crosstalk interaction. Conclusions The present study showed that this combination of Nimotuzumab and rapamycin could enhance glioma cell death, in an EGFR impartial manner. Moreover, the results showed that combination treatment was effective in TMZ-resistant glioma cells, suggesting that Nimotuzumab and rapamycin may potentially be of clinical relevance Irosustat for future treatment of human gliomas. Acknowledgements The authors wished to acknowledge Mark Schroeder and Jann Sarkaria (Mayo Clinic, Rochester, Minnesota) for providing the Irosustat GBM samples. Nimotuzumab was provided by Innogene Kalbiotech Pte Ltd, Singapore. Special thanks to Edita Aliwarga (National Cancer Centre) for her technical MMP15 support. Footnotes Competing interests The authors declare that they have no competing interests. Authors contributions CQD, TXY, HIA, SKC, YY, NV, LP participated in cell viability assay. CQD, NJP participated in immunoblot analysis. CQD, TXY, HIA, Irosustat HMF, NV, LP participated in the discussion of the results and writing of the manuscript. TCK and LPY conceived of the study, and participated in its design and coordination. NWH and LSH contributed to the human.