Calcium and calcium sensing receptor modulates the expression of thymidylate synthase, NAD(P)H:quinone oxidoreductase 1 and survivin in human colon carcinoma cells: promotion of cytotoxic response to mitomycin C and fluorouracil.
Ca(2+) and the cell-surface calcium sensing receptor (CaSR) constitute a novel and robust ligand/receptor system in regulating the proliferation and differentiation of colonic epithelial cells. Here we show that activation of CaSR by extracellular Ca(2+) (or CaSR agonists) enhanced the sensitivity of human colon carcinoma cells to mitomycin C (MMC) and fluorouracil (5-FU). Activation of CaSR up-regulated the expression of MMC activating enzyme, NAD(P)H:quinone oxidoreductase 1 (NQO-1) and down-regulated the expression of 5-FU target, thymidylate synthase (TS) and the anti-apoptotic protein survivin. Cells that were resistant to drugs expressed little or no CaSR but abundant amount of survivin. Disruption of CaSR expression by shRNA targeting the CaSR abrogated these modulating effects of CaSR activation on the expression of NQO1, TS, survivin and cytotoxic response to drugs. It is concluded that activation of CaSR can enhance colon cancer cell sensitivity to MMC and 5-FU and can modulate the expression of molecules involved in the cellular responses to these cytotoxic drugs.
Liu
Guangming
G
Southern Illinois University School of Medicine, SimmonsCooper Cancer Institute, Springfield, Illinois.
Hu
Xin
X
Southern Illinois University School of Medicine, SimmonsCooper Cancer Institute, Springfield, Illinois.
Varani
James
J
Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan.
Chakrabarty
Subhas
S
Southern Illinois University School of Medicine, SimmonsCooper Cancer Institute, Springfield, Illinois.
D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D015153:Blotting, Western; D002118:Calcium / Q000494:pharmacology*; D020013:Calcium Signaling; D049109:Cell Proliferation / Q000187:drug effects*; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D005472:Fluorouracil / Q000494:pharmacology; D006801:Humans; D007124:Immunoenzyme Techniques; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D016685:Mitomycin / Q000494:pharmacology; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology; D044169:Receptors, Calcium-Sensing / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000077022:Survivin; D013940:Thymidylate Synthase / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured
D000903:Antibiotics, Antineoplastic; D000964:Antimetabolites, Antineoplastic; C107489:BIRC5 protein, human; C095550:CASR protein, human; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D034741:RNA, Small Interfering; D044169:Receptors, Calcium-Sensing; D000077022:Survivin; D016685:Mitomycin; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human; D013940:Thymidylate Synthase; D002118:Calcium; D005472:Fluorouracil