AIM:To study KRAS/BRAF mutations in colorectalcancer(CRC)that influences the efficacy of treatment.To develop strategies for overcoming combination of treatment.METHODS:Five colonic cell-lines were investigated:DLD-1 with KRAS(G13D)mutation,HT 29 and Colo205 with BRAF(V600E)mutation as well as the wild type(Wt)cell-lines Caco2 and Colo-320.DLD-1(KRAS),HT-29(BRAF)and Caco2(Wt)cell lines were treated with cytokines(TNFα50 ng,IL-1β1 ng and IFNγ50ng)and harvested at different time points(1-24 h).KRAS inhibition was performed by the siRNA-approach.Two colorectal cancer cells DLD-1 and Caco2 were used for KRAS inhibition.About 70%confluency were confirmed before transfection with small interferring RNA(siRNA)oligonucleotides.All the synthetic siRNA sequences were designed in our laboratory.Total RNA and protein was isolated from the cells for RT-PCR and Western blotting.Densitometry of the Western blotting was analyzed with the Image J software(NIH).Results are shown as mean±SD.RESULTS:RT-PCR analysis in non-stimulated cells showed a low basal expression of TNFαand IL-1βin the DLD-1 KRAS-mutated cell-line,compared to Caco2wild type.No detection was found for IL-6 and IFNγin any of the studied cell lines.In contrast,pro-angiogenic chemokines(CXCL1,CXCL8)showed a high constitutive expression in the mutated cell-lines DLD-1(KRAS),HT-29 and Colo205(BRAF),compared to wild type(Caco2).The anti-angiogenic chemokine(CXCL10)showed a high basal expression in wild-type,compared to mutated cell-lines.KRAS down-regulation by siRNA showed a significant decrease in CXCL1 and CXCL10gene expression in the DLD-1(KRAS)cell-line in comparison to wild type(Caco2)at 72 h after KRAS silencing.In contrast,the specific KRAS inhibition resulted in an up-regulation of CXCL1 and CXCL10.The results of our study show a higher expression of pro-angiogenic chemokines at basal level in mutated cell-lines,which was further increased by cytokine treatment.CONCLUSION:To summarize,basal chemokine gene expression for pro-angiogenic chemokines was high in mutated as compared to wild type cell-lines.This reflects the likely existence of a different microenvironment in tumours consistent of wild type or mutated cells.This may help to rationalize the choice of molecular targets for suitable therapeutic investigation in clinical studies. AIM: To study KRAS / BRAF mutations in colorectal cancer (CRC) that influences the efficacy of treatment. To develop strategies for overcoming combination of treatment. METHODS: Five colonic cell-lines were investigated: DLD-1 with KRAS (G13D) mutation, HT 29 and Colo205 with BRAF (V600E) mutation as well as the wild type (Wt) cell-lines Caco2 and Colo-320. DLD-1 (KRAS) cytokines (TNFα50 ng, IL-1β1 ng and IFNγ50 ng) and harvested at different time points (1-24 h). KRAS inhibition was performed by siRNA-approach. Two colorectal cancer cells DLD-1 and Caco2 were used for KRAS inhibition. About 70% confluency were confirmed before transfection with small interferring RNA (siRNA) oligonucleotides. All synthetic siRNA sequences were designed in our laboratory. Total RNA and protein was isolated from the cells for RT-PCR and Western blotting. Sensitometry of the Western blotting was analyzed with the Image J software (NIH). Results are shown as mean ± SD.RESULTS: R T-PCR analysis in non-stimulated cells showed a low basal expression of TNFαand IL-1βin the DLD-1 KRAS-mutated cell-line, compared to Caco2 type. No detection was found for IL-6 and IFNγin any of the studied cells lines. In contrast, pro-angiogenic chemokines (CXCL1, CXCL8) showed a high constitutive expression in the mutated cell-lines DLD-1 (KRAS), HT- 29 and Colo205 (BRAF), compared to wild type (Caco2). anti-angiogenic chemokine (CXCL10) showed a high basal expression in wild-type, compared to mutated cell-lines. KRAS down-regulation by siRNA showed a significant decrease in CXCL1 and CXCL10 gene expression in the DLD-1 (KRAS) in comparison to wild type (Caco2) at 72 h after KRAS silencing.In contrast, the specific KRAS inhibition resulted in an up-regulation of CXCL1 and CXCL10.The results of our study show a higher expression of pro-angiogenic chemokines at basal level in mutated cell-lines, which was further increased by cytokine treatment. CONCLUSION: To summarize, basal chemokine gene expression for pro-angiogenic chemokines was high in mutated as compared to wild type cell-lines. This reflects the likely existence of a different microenvironment in tumours consistent of wild type or mutated cells. This may help to rationalize the choice of molecular targets for suitable therapeutic investigation in clinical studies.