Modulation of P-glycoprotein Expression by a Novel Nutrient Mixture in Multidrug Resistant Human Uterine Sarcoma Cell Line MES-SA/DX5 But Not in Drug Sensitive MES-SA Cell Line

M.W. Roomi, N.W. Roomi, M. Rath and A. Niedzwiecki
Dr. Rath Research Institute, Santa Clara, CA 95050

Presented at: 
101st Annual Meeting of the American Association for Cancer Research, Washington, D.C., April 17-21, 2010.

Published in:
Proceedings of the 101st Annual Meeting of the AACR, Vol 51,Abstract #2260, page 548

 

Abstract

Introduction: 
We have characterized a nutrient mixture containing lysine, proline, ascorbic acid and green tea extract as a novel antineoplastic agent with a broad spectrum of antitumor activity against a number of cancer cell lines.

Objective: 
We investigated the effect of NM on modulation of P-glycoprotein (Pgp) in the drug-resistant human uterine sarcoma cell line MES-SA/Dx5 and compared it with the effect on drug-sensitive cell line MES-SA. In addition we also studied the effect of NM on MMP expression and Rhodamine-123 accumulation and efflux.

Material and Methods:
Human drug insensitive uterine sarcoma cell line MES-SA/Dx5 and drug sensitive cell line MES-SA (ATCC) were grown in RPMI 1640 medium supplemented with fetal bovine serum and antibiotics. At near confluence, the cells were tested with NM at 0, 50, 100, 250, 500 and 1000 µg/ml, in triplicate at each dose. Cell proliferation was evaluated by MTT assay, MMPs by gelatinase zymography, and Pgp expression by Western blot and immunodetection using FITC-conjugated antibody and rhodamine-123 (Rh-123) accumulation and efflux assays.

Results: 
NM exhibited antiproliferative effect on MES-SA/Dx5, by 20% at 50 and 100 µg/ml and by 40% at 25, 500 and 1000 µg/ml, whereas in MES-SA cell line, NM showed dose-response toxicity of 40% at 50 and 30% at 1000 µg/ml. In both cell lines, zymography demonstrated a band corresponding to MMP-2 in normal cells and MMP-9 with PMA treatment. Both MMPs showed dose-response inhibition by NM. NM treatment also showed diminished dose-dependent Pgp expression by MES-SA/Dx5 cell line by Western blot and by immunodetection, whereas MES-SA did not exhibit Pgp by Western blot or by immunostaining. NM enhanced the accumulation and efflux of Pgp substrate Rh-123 in MES-SA/Dx5 uterine sarcoma cell line but not in the drug-sensitive cell line MES-SA.

Conclusions: 
In summary, this study demonstrated that Pgp is modulated by NM, which may be an attractive potential agent for therapeutic use in cancer treatment

Comment

P-glycoprotein expression is demonstrated in several cancers and is a mechanism by which cells acquire multidrug resistance. Thus, inhibition of Pgp is an area of intense research as a potential method of restoring tumor cell sensitivity to chemotherapeutic agents, We investigated the effect of NM on modulation of P-glycoprotein in the drug-resistant human uterine sarcoma cell line MES-SA/Dx5 and compared it with the effect on drug-sensitive cell line MES-SA. NM treatment showed diminished dose-dependent Pgp expression by MES-SA/Dx5 cell line by Western blot and by immunodetection, whereas MES-SA did not exhibit Pgp by Western blot or by immunostaining. NM enhanced the accumulation and efflux of Pgp substrate Rh-123 in MES-SA/Dx5 uterine sarcoma cell line but not in the drug-sensitive cell line MES-SA. These results are significant as they indicate the therapeutic potential of NM in treatment of drug-resistant human uterine sarcoma without the associated toxicity of chemotherapeutic agents that inhibit Pgp.


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