Isoform-specific up-regulation of plasma membrane Ca2+ATPase expression during colon and gastric cancer cell differentiation.
In this work we demonstrate a differentiation-induced up-regulation of the expression of plasma membrane Ca2+ATPase (PMCA) isoforms being present in various gastric/colon cancer cell types. We found PMCA1b as the major isoform in non-differentiated cancer cell lines, whereas the expression level of PMCA4b was significantly lower. Cell differentiation initiated with short chain fatty acids (SCFAs) and trichostatin A, or spontaneous differentiation of post-confluent cell cultures resulted in a marked induction of PMCA4b expression, while only moderately increased PMCA1b levels. Up-regulation of PMCA4b expression was demonstrated both at the protein and mRNA levels, and closely correlated with the induction of established differentiation markers. In contrast, the expression level of the Na+/K+-ATPase or that of the sarco/endoplasmic reticulum Ca2+ATPase 2 protein did not change significantly under these conditions. In membrane vesicles obtained from SCFA-treated gastric/colon cancer cells a marked increase in the PMCA-dependent Ca2+ transport activity was observed, indicating a general increase of PMCA function during the differentiation of these cancer cells. Because various PMCA isoforms display distinct functional characteristics, we suggest that up-regulated PMCA expression, together with a major switch in PMCA isoform pattern may significantly contribute to the differentiation of gastric/colon cancer cells. The analysis of PMCA expression may provide a new diagnostic tool for monitoring the tumor phenotype.
Ribiczey
Polett
P
National Medical Centre, Institute of Haematology and Immunology, Budapest, Hungary.
Tordai
Attila
A
Andrikovics
Hajnalka
H
Filoteo
Adelaida G
AG
Penniston
John T
JT
Enouf
Jocelyne
J
Enyedi
Agnes
A
Papp
Béla
B
Kovács
Tünde
T
D000818:Animals; D001692:Biological Transport; D019556:COS Cells; D018938:Caco-2 Cells; D002118:Calcium / Q000378:metabolism / Q000493:pharmacokinetics; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics*; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005227:Fatty Acids / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D019073:HT29 Cells; D006367:HeLa Cells; D006801:Humans; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism; D053499:Plasma Membrane Calcium-Transporting ATPases / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D015854:Up-Regulation / Q000187:drug effects
D005227:Fatty Acids; D007527:Isoenzymes; D012333:RNA, Messenger; D053499:Plasma Membrane Calcium-Transporting ATPases; D002118:Calcium