Project description:Basal cell carcinomas (BCCs) have relative genomic stability and relatively benign clinical behavior but whether these two are related causally is unknown. To investigate the effects of introducing genomic instability into murine BCCs, we have compared ionizing radiation-induced tumorigenesis in Ptch1+/- mice vs. that in Ptch1+/- mice carrying mutant Blm alleles. We found that BCCs in Ptch1+/- Blmtm3Brd/tm3Brd mice had a trend towards greater genomic instability as measured by array CGH and that these mice developed significantly more microscopic BCCs than did Ptch1+/- Blm+/tm3Brd or Ptch1+/- Blm+/+ mice. The mutant Blm alleles also markedly enhanced the formation of rhabdomyosarcomas (RMS), another cancer to which Ptch1+/- mice and PTCH1+/- (basal cell nevus syndrome) patients are susceptible. Highly recurrent but different copy number changes were associated with the two tumor types and included losses of chromosomes 4 and 10 in all BCCs and gain of chromosome 10 in 80% of RMSs. Loss of chromosome 11 and 13, including the Trp53 and Ptch1 loci respectively, occurred frequently in BCCs, suggesting tissue-specific selection for genes or pathways that collaborate with Ptch deficiency in tumorigenesis. Despite the quantitative differences, there was no dramatic qualitative difference in the BCC or RMS tumors associated with the mutant Blm genotype. We investigated the effect of Blm deficiency on ionizing radiation-induced basal cell carcinoma and rhabdomyosarcoma tumorigenesis in Ptch1+/- mice. Six BCC and five RMS samples were obtained from separate mice. Liver tissue from each mouse was used as the normal reference.
Project description:Basal cell carcinomas (BCCs) have relative genomic stability and relatively benign clinical behavior but whether these two are related causally is unknown. To investigate the effects of introducing genomic instability into murine BCCs, we have compared ionizing radiation-induced tumorigenesis in Ptch1+/- mice vs. that in Ptch1+/- mice carrying mutant Blm alleles. We found that BCCs in Ptch1+/- Blmtm3Brd/tm3Brd mice had a trend towards greater genomic instability as measured by array CGH and that these mice developed significantly more microscopic BCCs than did Ptch1+/- Blm+/tm3Brd or Ptch1+/- Blm+/+ mice. The mutant Blm alleles also markedly enhanced the formation of rhabdomyosarcomas (RMS), another cancer to which Ptch1+/- mice and PTCH1+/- (basal cell nevus syndrome) patients are susceptible. Highly recurrent but different copy number changes were associated with the two tumor types and included losses of chromosomes 4 and 10 in all BCCs and gain of chromosome 10 in 80% of RMSs. Loss of chromosome 11 and 13, including the Trp53 and Ptch1 loci respectively, occurred frequently in BCCs, suggesting tissue-specific selection for genes or pathways that collaborate with Ptch deficiency in tumorigenesis. Despite the quantitative differences, there was no dramatic qualitative difference in the BCC or RMS tumors associated with the mutant Blm genotype.
Project description:A series of conditional mouse models of embryonal rhabdomyosarcoma, alveolar rhabdomyosarcoma and spindle cell sarcoma were generated and validated for relavence to corresponding human cancers. Conditional mouse models of embryonal rhabdomyosarcoma, alveolar rhabdomyosarcoma and spindle cell sarcoma were created by activation or deletion of Pax3:Fkhr, p53, Ptch1 or Rb1 genes.
Project description:Activation of the Sonic hedgehog (Shh) signaling pathway due to Patched 1 (PTCH1) mutation is a key event in sporadic and familial basal cell carcinoma (BCC) development. To find out the specific pathway for therapeutic intervention, we developed a mouse BCC model by skin specific Ptch1 inactivation, and sought to identify novel Shh targets. We used microarrays to identify up-regulated genes in mouse BCC. We used microarrays to identify down-regulated genes in mouse BCC cell line by cyclopamine.
Project description:Genomic radiation signature illuminates low-dose effects with sharply reflected transcriptome in Ptch1-deficient medulloblastomas. Cancer risks of low-dose radiation are of great concern especially in relation to rapidly increasing medical exposures; however, their accurate assessments cope with many challenges and difficulties, partly due to the inability to distinguish radiation-induced tumors from spontaneous ones. Here, we analyzed the dose-dependent effect of radiation on medulloblastoma development in Ptch1 heterozygous mice on C3B6F1 background. The incidence and latency of medulloblastoma increased and shortened with increasing radiation dose, respectively. Amazingly, radiation contributed to tumorigenesis even at 50 mGy and 100% of mice got medulloblastoma with 1.5 Gy. Loss of heterozygosity (LOH) analysis on a total of 164 tumors indicated that spontaneous tumors showed LOH in broad regions on chromosome 13, including Ptch1 and distally-extending telomeric portion (S-type). In contrast, tumors developed after 3 Gy irradiation exhibited interstitial losses around Ptch1 (R-type). A clear dose-dependent increase in the proportion of R-type tumor at intermediate doses suggested R-type to be a reliable radiation signature. Array-CGH analysis indicated the R-type-specific copy-number reduction around Ptch1 and LOH-type-independent frequent gains of whole chromosome 6. Integrated expression microarray analysis indicated that expression levels of many genes within the altered genomic regions faithfully reflected the genomic copy-number changes. Furthermore, it was also suggested that these expression changes in turn influenced on many other genes, such as Tgfb2 and Tgfb3, on widespread genomic regions. This is the first demonstration that radiation-induced tumors developed after low-dose irradiation can be characterized quite precisely by interstitial deletion of Ptch1 and by associated gene expression profile. Gene expression in 3 normal cerebellum tissues and 12 medulloblastomas was measured.
Project description:Genomic radiation signature illuminates low-dose effects with sharply reflected transcriptome in Ptch1-deficient medulloblastomas. Cancer risks of low-dose radiation are of great concern especially in relation to rapidly increasing medical exposures; however, their accurate assessments cope with many challenges and difficulties, partly due to the inability to distinguish radiation-induced tumors from spontaneous ones. Here, we analyzed the dose-dependent effect of radiation on medulloblastoma development in Ptch1 heterozygous mice on C3B6F1 background. The incidence and latency of medulloblastoma increased and shortened with increasing radiation dose, respectively. Amazingly, radiation contributed to tumorigenesis even at 50 mGy and 100% of mice got medulloblastoma with 1.5 Gy. Loss of heterozygosity (LOH) analysis on a total of 164 tumors indicated that spontaneous tumors showed LOH in broad regions on chromosome 13, including Ptch1 and distally-extending telomeric portion (S-type). In contrast, tumors developed after 3 Gy irradiation exhibited interstitial losses around Ptch1 (R-type). A clear dose-dependent increase in the proportion of R-type tumor at intermediate doses suggested R-type to be a reliable radiation signature. Array-CGH analysis indicated the R-type-specific copy-number reduction around Ptch1 and LOH-type-independent frequent gains of whole chromosome 6. Integrated expression microarray analysis indicated that expression levels of many genes within the altered genomic regions faithfully reflected the genomic copy-number changes. Furthermore, it was also suggested that these expression changes in turn influenced on many other genes, such as Tgfb2 and Tgfb3, on widespread genomic regions. This is the first demonstration that radiation-induced tumors developed after low-dose irradiation can be characterized quite precisely by interstitial deletion of Ptch1 and by associated gene expression profile. Three medulloblastomas were analyzed by array-CGH method.
Project description:Genomic radiation signature illuminates low-dose effects with sharply reflected transcriptome in Ptch1-deficient medulloblastomas. Cancer risks of low-dose radiation are of great concern especially in relation to rapidly increasing medical exposures; however, their accurate assessments cope with many challenges and difficulties, partly due to the inability to distinguish radiation-induced tumors from spontaneous ones. Here, we analyzed the dose-dependent effect of radiation on medulloblastoma development in Ptch1 heterozygous mice on C3B6F1 background. The incidence and latency of medulloblastoma increased and shortened with increasing radiation dose, respectively. Amazingly, radiation contributed to tumorigenesis even at 50 mGy and 100% of mice got medulloblastoma with 1.5 Gy. Loss of heterozygosity (LOH) analysis on a total of 164 tumors indicated that spontaneous tumors showed LOH in broad regions on chromosome 13, including Ptch1 and distally-extending telomeric portion (S-type). In contrast, tumors developed after 3 Gy irradiation exhibited interstitial losses around Ptch1 (R-type). A clear dose-dependent increase in the proportion of R-type tumor at intermediate doses suggested R-type to be a reliable radiation signature. Array-CGH analysis indicated the R-type-specific copy-number reduction around Ptch1 and LOH-type-independent frequent gains of whole chromosome 6. Integrated expression microarray analysis indicated that expression levels of many genes within the altered genomic regions faithfully reflected the genomic copy-number changes. Furthermore, it was also suggested that these expression changes in turn influenced on many other genes, such as Tgfb2 and Tgfb3, on widespread genomic regions. This is the first demonstration that radiation-induced tumors developed after low-dose irradiation can be characterized quite precisely by interstitial deletion of Ptch1 and by associated gene expression profile. Twelve medulloblastomas were analyzed by array-CGH method.