BRCA1-related breast cancer represents a distinct clinical entity characterized by basal-like molecular phenotype. HCC1937 is a BRCA1-defective breast cancer cell line which discloses higher sensitivity to cisplatinum (CDDP) as compared to the BRCA1 full-length cDNA transfected clone HCC1937/wtBRCA1. To study the molecular bases of BRCA1-related differential sensitivity to the drug, we have analyzed the whole gene expression profile of HCC1937 and HCC1937/wtBRCA1 cells following in vivo and in vitro exposure of tumour cells to CDDP. Differential in vivo sensitivity was evaluated in xenografted tumors in SCID mice after 4 weeks of treatment with CDDP (5 mg/kg) or vehicle. Tumors were retrieved from animals 4 hours after the last dose of drug or vehicle. In vitro data were obtained exposing HCC1937 and HCC1937/wtBRCA1 cell lines to CDDP at IC50 doses of 30 and 70µM, or at 60 or 140µM respectively, for 3, 12 and 24 hours. Gene expression profiling was performed by Affymetrix® technology using GeneArray 1.0ST. Array data were analyzed using Gene Expression Console, GeneSpring software and Ingenuity Pathway Analysis (IPA)®. We found up-regulation of G2/M DNA damage checkpoint pathway, in a dose- and time-dependent manner, as well as down-regulation of Notch signaling pathway in HCC1937 cells, after treatment with CDDP in vitro. Both pathways were not affected in BRCA1-reconstituted cells. Notch signaling pathway plays a key role in normal development of several tissues and its aberrant activation is linked with breast cancer tumourigenesis. Our findings suggest that sensitivity of the BRCA1-defective cells to CDDP exposure is related to the DNA-damage repair machinery due to BRCA1-deficiency but also to the modulation of survival pathways triggered by BRCA1. In vivo data analysis of HCC1937/wtBRCA1 tumours exposed to CDDP identified modulation of pathways involving AKT3 and PRKAR2B, also known as RII-BETA, a cAMP-dependent protein kinase, whereas no Notch signaling pathway modulation was detected. In conclusion, reconstituted expression of BRCA1 induces resistance to CDDP in vitro and in vivo but produces a different transcriptional response to drug exposure. This effect could be related to the different growth and environmental milieu as well as to the different exposure conditions. Signaling pathways involving Notch, AKT and RII-BETA are involved in these events. Our data reinforce the concept that BRCA1 offers a molecular marker for individualized therapeutical options in breast cancer patients.
Differential transcriptional response to cisplatinum in BRCA1-defective versus BRCA1-reconstituted breast cancer cells by microarrays
CANNATARO M;Veltri Pierangelo;GUZZI P
2009-01-01
Abstract
BRCA1-related breast cancer represents a distinct clinical entity characterized by basal-like molecular phenotype. HCC1937 is a BRCA1-defective breast cancer cell line which discloses higher sensitivity to cisplatinum (CDDP) as compared to the BRCA1 full-length cDNA transfected clone HCC1937/wtBRCA1. To study the molecular bases of BRCA1-related differential sensitivity to the drug, we have analyzed the whole gene expression profile of HCC1937 and HCC1937/wtBRCA1 cells following in vivo and in vitro exposure of tumour cells to CDDP. Differential in vivo sensitivity was evaluated in xenografted tumors in SCID mice after 4 weeks of treatment with CDDP (5 mg/kg) or vehicle. Tumors were retrieved from animals 4 hours after the last dose of drug or vehicle. In vitro data were obtained exposing HCC1937 and HCC1937/wtBRCA1 cell lines to CDDP at IC50 doses of 30 and 70µM, or at 60 or 140µM respectively, for 3, 12 and 24 hours. Gene expression profiling was performed by Affymetrix® technology using GeneArray 1.0ST. Array data were analyzed using Gene Expression Console, GeneSpring software and Ingenuity Pathway Analysis (IPA)®. We found up-regulation of G2/M DNA damage checkpoint pathway, in a dose- and time-dependent manner, as well as down-regulation of Notch signaling pathway in HCC1937 cells, after treatment with CDDP in vitro. Both pathways were not affected in BRCA1-reconstituted cells. Notch signaling pathway plays a key role in normal development of several tissues and its aberrant activation is linked with breast cancer tumourigenesis. Our findings suggest that sensitivity of the BRCA1-defective cells to CDDP exposure is related to the DNA-damage repair machinery due to BRCA1-deficiency but also to the modulation of survival pathways triggered by BRCA1. In vivo data analysis of HCC1937/wtBRCA1 tumours exposed to CDDP identified modulation of pathways involving AKT3 and PRKAR2B, also known as RII-BETA, a cAMP-dependent protein kinase, whereas no Notch signaling pathway modulation was detected. In conclusion, reconstituted expression of BRCA1 induces resistance to CDDP in vitro and in vivo but produces a different transcriptional response to drug exposure. This effect could be related to the different growth and environmental milieu as well as to the different exposure conditions. Signaling pathways involving Notch, AKT and RII-BETA are involved in these events. Our data reinforce the concept that BRCA1 offers a molecular marker for individualized therapeutical options in breast cancer patients.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
