Extended stage small cell lung cancer (SCLC) responds to platinum/vepeside-based first-line chemotherapy but relapses early as drug-resistant tumor associated with a dismal prognosis. A pair of SCLC cell lines obtaine...Extended stage small cell lung cancer (SCLC) responds to platinum/vepeside-based first-line chemotherapy but relapses early as drug-resistant tumor associated with a dismal prognosis. A pair of SCLC cell lines obtained from a single patient at different time points during treatment allows for the investigation of the changes in gene expression prior to (GLC14) and following cycles of chemotherapy and irradiation (GLC19). GLC19 cells were reported to reveal an increased doubling time and exhibit increased chemoresistance to doxorubicin, etoposide, melphalan and vinblastine. Upregulated transcripts in GLC19, as assessed by microarray analysis, comprised proteins involved in regulation of cellular growth (NGFRAP1/BEX3), adhesion, glutathione metabolism and, in particular, WNT/Notch pathways and the putative cancer stem cell phenotype (CD44, ALDH1A1, and AKR1C1/13). Metallothioneins, tubulins TUBA3/4 and tumor protein p53 inducible protein 11 (TP53IP11) were downregulated in this cell line compared to GLC14. Except increased expression of glutathione transferases no classical markers of chemoresistance were found, pointing to a role of altered growth control/differentiation and reduced accessibility of this SCLC tumor cells growing as multicellular spheroids. In conclusion, treatment of this single SCLC with cyclophosphamide, doxorubicin and etoposide (CDE) followed by radiotherapy ultimately resulted in an enrichment of tumor cells displaying the typical signature of tumor-initiating or cancer stem cells (CIC/CSC).展开更多
Extended-stage small cell lung cancer (SCLC) responds to platinum/vepeside-based first-line chemotherapy but relapses rapidly as drug-resistant tumor. Topotecan (TPT) is the single chemotherapeutic agent approved for ...Extended-stage small cell lung cancer (SCLC) responds to platinum/vepeside-based first-line chemotherapy but relapses rapidly as drug-resistant tumor. Topotecan (TPT) is the single chemotherapeutic agent approved for second-line treatment of SCLC. However, the response to TPT is short-lived and novel treatment modalities need to be developed. Sequential treatment of cytotoxic drugs and inhibitors of cyclin-dependent kinases (CDKs) showed promising preclinical anticancer activity and, in the present work, combinations of TPT with CDK inhibitors olomoucine, roscovitine and CDK4I are shown to exhibit synergistic cytotoxic activity against SCLC cell lines. Highest activity was found against TPT-resistant NCI-H417 and DMS153 cell lines and moderate chemosensitizing effects against a primary SCLC cell line and sensitive GLC19 cells at levels of CDK inhibitors which exerted low toxicity. A combination of 0.6 μM TPT with 0.6 μM roscovitine, exhibiting no significant cytotoxicity as single agents, reduced viability of the TPT-resistant NCI-H417 line (IC50 > 10 μM) by 50%. In the TPT resistant cell lines olomoucine and roscovitine, targeting CDK1,2,5,7, were highly effective, whereas in the more sensitive cell lines CDK4I, inhibiting mainly CDK4/6, showed activity. In NCI-417 cells, preincubation with roscovitine for one day proved synergistic with TPT. Thus, in good accordance with previous findings, CDK inhibitors are able to convert SCLC cancer cells which are cell-cycle arrested by a blockade of topoisomerase I by TPT to apoptotic cells. Since nowadays several CDK inhibitors are at various phases of clinical testing their combination with TPT seems to constitute a promising approach to improve second-line chemotherapy in SCLC.展开更多
文摘Extended stage small cell lung cancer (SCLC) responds to platinum/vepeside-based first-line chemotherapy but relapses early as drug-resistant tumor associated with a dismal prognosis. A pair of SCLC cell lines obtained from a single patient at different time points during treatment allows for the investigation of the changes in gene expression prior to (GLC14) and following cycles of chemotherapy and irradiation (GLC19). GLC19 cells were reported to reveal an increased doubling time and exhibit increased chemoresistance to doxorubicin, etoposide, melphalan and vinblastine. Upregulated transcripts in GLC19, as assessed by microarray analysis, comprised proteins involved in regulation of cellular growth (NGFRAP1/BEX3), adhesion, glutathione metabolism and, in particular, WNT/Notch pathways and the putative cancer stem cell phenotype (CD44, ALDH1A1, and AKR1C1/13). Metallothioneins, tubulins TUBA3/4 and tumor protein p53 inducible protein 11 (TP53IP11) were downregulated in this cell line compared to GLC14. Except increased expression of glutathione transferases no classical markers of chemoresistance were found, pointing to a role of altered growth control/differentiation and reduced accessibility of this SCLC tumor cells growing as multicellular spheroids. In conclusion, treatment of this single SCLC with cyclophosphamide, doxorubicin and etoposide (CDE) followed by radiotherapy ultimately resulted in an enrichment of tumor cells displaying the typical signature of tumor-initiating or cancer stem cells (CIC/CSC).
文摘Extended-stage small cell lung cancer (SCLC) responds to platinum/vepeside-based first-line chemotherapy but relapses rapidly as drug-resistant tumor. Topotecan (TPT) is the single chemotherapeutic agent approved for second-line treatment of SCLC. However, the response to TPT is short-lived and novel treatment modalities need to be developed. Sequential treatment of cytotoxic drugs and inhibitors of cyclin-dependent kinases (CDKs) showed promising preclinical anticancer activity and, in the present work, combinations of TPT with CDK inhibitors olomoucine, roscovitine and CDK4I are shown to exhibit synergistic cytotoxic activity against SCLC cell lines. Highest activity was found against TPT-resistant NCI-H417 and DMS153 cell lines and moderate chemosensitizing effects against a primary SCLC cell line and sensitive GLC19 cells at levels of CDK inhibitors which exerted low toxicity. A combination of 0.6 μM TPT with 0.6 μM roscovitine, exhibiting no significant cytotoxicity as single agents, reduced viability of the TPT-resistant NCI-H417 line (IC50 > 10 μM) by 50%. In the TPT resistant cell lines olomoucine and roscovitine, targeting CDK1,2,5,7, were highly effective, whereas in the more sensitive cell lines CDK4I, inhibiting mainly CDK4/6, showed activity. In NCI-417 cells, preincubation with roscovitine for one day proved synergistic with TPT. Thus, in good accordance with previous findings, CDK inhibitors are able to convert SCLC cancer cells which are cell-cycle arrested by a blockade of topoisomerase I by TPT to apoptotic cells. Since nowadays several CDK inhibitors are at various phases of clinical testing their combination with TPT seems to constitute a promising approach to improve second-line chemotherapy in SCLC.
