TY - JOUR
T1 - Epigenetic inactivation of laminin-5-encoding genes in lung cancers
AU - Sathyanarayana, Ubaradka G.
AU - Toyooka, Shinichi
AU - Padar, Asha
AU - Takahashi, Takashi
AU - Brambilla, Elizabeth
AU - Minna, John D.
AU - Gazdar, Adi F.
PY - 2003/7/1
Y1 - 2003/7/1
N2 - Purpose: We investigated the loss of expression of three laminin-5 (LN5)-encoding genes in lung cancer cell lines and elucidated the mechanism of inactivation of the genes in lung cancer cell lines and tumors. Experimental Design: We examined the expression of LN5-encoding genes by reverse transcription-PCR in 49 lung cancer cell lines. To elucidate the mechanism of gene silencing, we treated expression-negative cell lines (two for each gene) with a demethylating agent and examined the restoration of expression by reverse transcription-PCR. We dissected out the methylation patterns of CpG sites unique to the promoter regions of LN5-encoding genes by bisulfite genomic sequencing of expression-negative cell lines. We designed methylation-specific primers and validated the methylation status of the promoter regions in lung cancer cell lines using methylation-specific PCR. We further studied the methylation patterns of primary non-small cell lung cancer [NSCLC (n = 36)], small cell lung cancer [SCLC (n = 26)], and carcinoids (n = 24) tumors. Results: We observed frequent losses of expression in NSCLC (20-60%) and SCLC (65-86%) cell lines. Expression of one or more genes was lost in 90% of SCLC cell lines and 65% of NSCLC cell lines. Treatment of expression-negative cell lines with demethylating agent restored expression in all of the cases. Methylation of LN5-encoding genes was present more frequently in SCLC cell lines (60-80%) than in NSCLC cell lines (15-60%), and at least one gene was methylated in 95% of SCLC and 60% of NSCLC cell lines. The concordances between loss of expression and methylation in 40 lung cancer cell lines for the three genes (90-95%) were statistically significant. Methylation was more frequent in SCLC tumors (58-77%) than in NSCLC tumors (22-42%) and carcinoids (13-33%), and at least one gene was methylated in 92% of SCLC tumors, 47% of NSCLC tumors, and 33% of carcinoids. Conclusions: Our results demonstrate frequent epigenetic inactivation of LN5-encoding genes in lung cancers, and these findings are of biological interest and are potentially of clinical importance.
AB - Purpose: We investigated the loss of expression of three laminin-5 (LN5)-encoding genes in lung cancer cell lines and elucidated the mechanism of inactivation of the genes in lung cancer cell lines and tumors. Experimental Design: We examined the expression of LN5-encoding genes by reverse transcription-PCR in 49 lung cancer cell lines. To elucidate the mechanism of gene silencing, we treated expression-negative cell lines (two for each gene) with a demethylating agent and examined the restoration of expression by reverse transcription-PCR. We dissected out the methylation patterns of CpG sites unique to the promoter regions of LN5-encoding genes by bisulfite genomic sequencing of expression-negative cell lines. We designed methylation-specific primers and validated the methylation status of the promoter regions in lung cancer cell lines using methylation-specific PCR. We further studied the methylation patterns of primary non-small cell lung cancer [NSCLC (n = 36)], small cell lung cancer [SCLC (n = 26)], and carcinoids (n = 24) tumors. Results: We observed frequent losses of expression in NSCLC (20-60%) and SCLC (65-86%) cell lines. Expression of one or more genes was lost in 90% of SCLC cell lines and 65% of NSCLC cell lines. Treatment of expression-negative cell lines with demethylating agent restored expression in all of the cases. Methylation of LN5-encoding genes was present more frequently in SCLC cell lines (60-80%) than in NSCLC cell lines (15-60%), and at least one gene was methylated in 95% of SCLC and 60% of NSCLC cell lines. The concordances between loss of expression and methylation in 40 lung cancer cell lines for the three genes (90-95%) were statistically significant. Methylation was more frequent in SCLC tumors (58-77%) than in NSCLC tumors (22-42%) and carcinoids (13-33%), and at least one gene was methylated in 92% of SCLC tumors, 47% of NSCLC tumors, and 33% of carcinoids. Conclusions: Our results demonstrate frequent epigenetic inactivation of LN5-encoding genes in lung cancers, and these findings are of biological interest and are potentially of clinical importance.
UR - http://www.scopus.com/inward/record.url?scp=0037817329&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0037817329&partnerID=8YFLogxK
M3 - Article
C2 - 12855645
AN - SCOPUS:0037817329
SN - 1078-0432
VL - 9
SP - 2665
EP - 2672
JO - Clinical Cancer Research
JF - Clinical Cancer Research
IS - 7
ER -