ABSTRACT
Objective To investigate the synergistic effects of 9-cis-retinoic acid(9-cis-RA) and 8-cl-cAMP on growth inhibition and apoptosis induction in H460 and H292 cell lines of non-small-cell lung cancer(NSCLC). Methods Experimental groups included 9-cis-RA groups(1,5,10 and 20 ?mol/L),8-cl-cAMP groups(5,10,20 and 50 ?mol/L),9-cis-RA(5 and 10 ?mol/L) combined with 8-cl-cAMP(10 ?mol/L) groups and blank control group.The cell growth inhibition rates were detected by trypan blue staining,and the apoptosis of H460 and H292 cells were observed by Hoechst33258 fluorescence microscope,DNA gel electrophoresis and flow cytometer(FCM). Results 9-cis-RA inhibited the growth of H460 cells in a time-and dose-dependent manner,and induced the apoptosis of H460 cells(P
ABSTRACT
Previous reports raised question as to whether 8-chloro-cyclic adenosine 3,5-monophosphate (8-Cl-cAMP) is a prodrug for its metabolite, 8-Cl-adenosine which exerts growth inhibition in a broad spectrum of cancer cells. The present study was carried out to clarify overall cellular affects of 8-Cl-cAMP and 8-Cl-adenosine on SK-N-DZ human neuroblastoma cells by ystematically characterizing gene expression using radioactive human cDNA microarray. Microarray was prepared with PCR-amplified cDNA of 2,304 known genes spotted on nylon membranes, employing (1)P-labeled cDNAs of SK-N-DZ cells as a probe. the expression levels of approximately 100 cDNAs, representing about 8% of the total DNA elements on the array, were altered in 8-Cl-adenosine- or 8-Cl-cAMP-treated cells, respectively. The genome-wide expression of the two samples exhibited partial overlaps; different sets of up-regulated genes but the same set of down-regulated genes. 8-Cl-adenosine treatment up- egulated genes involved in differentiation and development (LIM protein, connexin 26, neogenin, neurofilament triplet L protein and p21( WAF1/CIP1)) and immune response such as natural killer cells protein 4, and down-regulated ones involved in proliferation and transformation (transforming growth factor-beta, DYRK2, urokinase-type plasminogen activator and proteins involved in transcription and translation) which were in close parallel with those by 8-Cl-cAMP. Our results indicated that the two drugs shared common genomic pathways for the down-regulation of certain genes, but used distinct pathways for the up-regulation of different gene clusters. Based on the findings, we suggest that the anti-cancer activity of 8-Cl-cAMP results at least in part through 8-Cl-adenosine. Thus, the systematic use of DNA arrays can provide insight into the dynamic cellular pathways involved in anticancer activities of chemotherapeutics.
Subject(s)
Humans , 2-Chloroadenosine/analogs & derivatives , 8-Bromo Cyclic Adenosine Monophosphate/analogs & derivatives , Antineoplastic Agents/chemistry , Blotting, Western , Gene Expression Profiling , Gene Expression Regulation, Neoplastic/drug effects , Genome, Human , Neuroblastoma/genetics , Oligonucleotide Array Sequence Analysis , Reproducibility of Results , Tumor Cells, Cultured , Up-Regulation/drug effectsABSTRACT
The overexpression of EGFR and the typeⅠcAMPdependent protein kinase(PKAⅠ) has been found in most cancer tissue and tumour cells.The blockade of EGFR activation by using anti-EGFR monoclonal antibodies(MAbs) and inhibition of PKAⅠ expression by specific pharmacological agents such as the selective cAMP analogue 8-Cl-cAMP has been proposed as a potential anticancer therapy.We have shown that an interaction between EGFR and PKAⅠ occurs through direct binding of the RⅠsubunit to the Grb2 adaptor protein.We have demonstrated that the functional interaction between the EGFR and the PKAⅠ pathways could have potential therapeutic implications.In fact,the combined interference with both EGFR and PKAⅠ with specific pharmacological agents,has a cooperative antiproliferative effect on human cancer cell lines in vitro and in vivo.Studies on the antitumor activity of this combination are under human clinical trial evaluation.