The effect of all-trans retinoic acid on gap junctional intercellular communication and connexin 43 gene expression in glioma cells.
OBJECTIVE
To illuminate the regulating effect of all-trans retinoic acid (ATRA) on gap junctional intercellular communication (GJIC) and connexin 43 (Cx43) gene expression in glioma cells, which is tissue- and organ-specific.


METHODS
Rat C6 glioma cells were exposed to ATRA at a concentration of 1, 10, 100 micromol/L and the GJIC function of the cells was examined with scrape-loading dye transfer assay 24 hours, 48 hours and 72 hours after ATRA treatment. The effect of ATRA on Cx43 gene expression was measured with semiquantitative reverse transcription polymerase chain reaction (RT-PCR) 24 hours after ATRA exposure.


RESULTS
The GJIC function of C6 glioma cells was significantly increased by ATRA at each concentration applied. The dye passed 4 to 5 rows of cells from the scraping edge in ATRA treated cells, but only 1 or 2 rows in the control. The augment effect was observed 24 hours after each concentration ATRA treatment, and lasted till 72 hours after treatment with 1 micromol/L and 10 micromol/L ATRA. Forty-eight hours after exposed to 100 micromol/L ATRA, the enhancement of GJIC was less obvious. There was no significant increase induced by ATRA on the transcription of Cx43 gene, as demonstrated by semiquantitative RT-PCR.


CONCLUSIONS
ATRA turned out to be a potent enhancer on GJIC function in C6 glioma cells, andthe enhancement effect was most probable at post-transcriptional level.
Zhang
Xuefeng
X
Neurosurgery Department, Peking Union Medical College Hospital, CAMS & PUMC, Beijing 100730.
Ren
Zuyuan
Z
Zuo
Jin
J
Su
Changbao
C
Wang
Renzhi
R
Chang
Yongsheng
Y
Fang
Fude
F
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology; D018031:Connexin 43 / Q000096:biosynthesis* / Q000235:genetics; D017629:Gap Junctions / Q000502:physiology*; D015870:Gene Expression; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D014212:Tretinoin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D018031:Connexin 43; D012333:RNA, Messenger; D014212:Tretinoin