Project description:CD24 is a potential oncogene reported to be overexpressed in a large variety of human malignancies. We have shown that CD24 is overexpressed in 90% of colorectal tumors at a fairly early stage in the multistep process of carcinogenesis. Anti-CD24 monoclonal antibodies (mAb) induce a significant growth inhibition in colorectal and pancreatic cancer cell lines that express the protein. This study is designed to investigate further the effects of CD24 down-regulation using mAb or small interfering RNA in vitro and in vivo. Western blot analysis showed that anti-CD24 mAb induced CD24 protein down-regulation through lysosomal degradation. mAb augmented growth inhibition in combination with five classic chemotherapies. Xenograft models in vivo showed that tumor growth was significantly reduced in mAb-treated mice. Similarly, stable growth inhibition of cancer cell lines was achieved by down-regulation of CD24 expression using short hairpin RNA (shRNA). The produced clones proliferated more slowly, reached lower saturation densities, and showed impaired motility. Most importantly, down-regulation of CD24 retarded tumorigenicity of human cancer cell lines in nude mice. Microarray analysis revealed a similar pattern of gene expression alterations when cells were subjected to anti-CD24 mAb or shRNA. Genes in the Ras pathway, mitogenactivated protein kinase, or BCL-2 family and others of oncogenic association were frequently down-regulated. As a putative new oncogene that is overexpressed in gastrointestinal malignancies early in the carcinogenesis process, CD24 is a potential target for early intervention in the prevention and treatment of cancer. The study compared gene expression profiles between human CRC cells HT29 before and after expression of 1 and 2 shRNA vectors directed at the human CD24 gene, GFP control gene, HT29 cells and Colo357, human pancreatic cancer cells, before and after the inhibition of the CD24 molecule using 72h treatment with anti-CD24 monoclonal antibodies.
Project description:CD24 is a potential oncogene reported to be overexpressed in a large variety of human malignancies. We have shown that CD24 is overexpressed in 90% of colorectal tumors at a fairly early stage in the multistep process of carcinogenesis. Anti-CD24 monoclonal antibodies (mAb) induce a significant growth inhibition in colorectal and pancreatic cancer cell lines that express the protein. This study is designed to investigate further the effects of CD24 down-regulation using mAb or small interfering RNA in vitro and in vivo. Western blot analysis showed that anti-CD24 mAb induced CD24 protein down-regulation through lysosomal degradation. mAb augmented growth inhibition in combination with five classic chemotherapies. Xenograft models in vivo showed that tumor growth was significantly reduced in mAb-treated mice. Similarly, stable growth inhibition of cancer cell lines was achieved by down-regulation of CD24 expression using short hairpin RNA (shRNA). The produced clones proliferated more slowly, reached lower saturation densities, and showed impaired motility. Most importantly, down-regulation of CD24 retarded tumorigenicity of human cancer cell lines in nude mice. Microarray analysis revealed a similar pattern of gene expression alterations when cells were subjected to anti-CD24 mAb or shRNA. Genes in the Ras pathway, mitogenactivated protein kinase, or BCL-2 family and others of oncogenic association were frequently down-regulated. As a putative new oncogene that is overexpressed in gastrointestinal malignancies early in the carcinogenesis process, CD24 is a potential target for early intervention in the prevention and treatment of cancer.
Project description:In pancreatic cancer the survival rate is low, as the available treatment options usually only extend survival and seldom produce a cure. Drug resistance and disease reoccurrence is the typical reason for death after cancer diagnosis. 5-Fluorouracil (5-FU) is the main chemostatic used in first line therapy. However the majority of the tumors become resistant to treatment. To investigate acquired 5-FU resistance in pancreatic adenocarcinoma, we established chemoresistant monoclonal cell lines from the Panc03.27 cell line by long-term exposure to 5-FU. In addition to increased expression of markers associated with multidrug resistance, the 5-FU resistant clones showed alterations typical of the process of epithelial-to-mesenchymal transition (EMT), including upregulation of mesenchymal markers and increased invasiveness. Microarray analysis revealed the L1CAM pathway as one of the most upregulated pathways in the chemoresistant clones, which was confirmed on RNA and protein levels. Expression of the adhesion molecule L1CAM is associated with a chemoresistant and migratory phenotype of pancreatic cancer. Using esiRNA targeting L1CAM, or by blocking the extracellular part of L1CAM with monoclonal antibodies, we discovered that the increased invasiveness observed in the chemoresistant cells depends on L1CAM. Using esiRNA targeting β-catenin and/or Slug, we discovered that L1CAM expression depends on Slug rather than β-catenin in the 5-FU resistant cells. We demonstrate a functional link between Slug and the expression level of L1CAM in pancreatic cancer cells having undergone EMT following long-term exposure to 5-FU. Our findings provide further insight into the molecular mechanisms leading to a chemoresistant and migratory phenotype in pancreatic cancer cells and indicate the importance of Slug-induced L1CAM in refractory pancreatic cancer. Examination of expression of 5-Fluorouracil (5-FU) Panc03.27 cell line resistant clone versus expression of 5-FU sensitive clones (NT) in 4 replicates per cell lines
Project description:We describe a relationship between CD24 and the Hedgehog (Hh) ligand Sonic Hedgehog (SHH), and reveal a role for this relationship in the induction of a malignant phenotype in breast cancer. Anchorage-dependent proliferation, anchorage-independent proliferation, invasiveness, and tumorigenicity in breast cancer cells (BCCs) transfected with siRNA and plasmid targeting Hh signaling, CD24, and STAT1 were investigated. CD24 siRNA-transfected BCCs demonstrated higher expression of SHH and GLI1, increased anchorage-independent proliferation, enhanced invasiveness and superior tumorigenicity compared with control. Conversely, CD24 forced-expressing BCCs possessed decreased SHH and GLI1 expression, anchorage-independent proliferation, and invasiveness. Suppression of SHH decreased invasiveness through inhibition of matrix metalloproteinase (MMP)-2 expression, GLI1 expression, anchorage-independent proliferation, tumorigenicity, and tumor volume in vivo in CD24 siRNA-transfected BCCs. DNA microarray analysis identified STAT1 as a connection between CD24 and SHH. CD24 siRNA-transfected BCCs with concurrent STAT1 inhibition exhibited decreased SHH expression, invasiveness, anchorage-independent proliferation, tumorigenicity, and tumor volume in vivo. Consistently, STAT1 over-expression induced elevated SHH expression, invasiveness, and anchorage-independent proliferation in BCCs. These results suggest that CD24 suppresses development of a malignant phenotype by down-regulating SHH transcription through STAT1 inhibition.
Project description:We describe a relationship between CD24 and the Hedgehog (Hh) ligand Sonic Hedgehog (SHH), and reveal a role for this relationship in the induction of a malignant phenotype in breast cancer. Anchorage-dependent proliferation, anchorage-independent proliferation, invasiveness, and tumorigenicity in breast cancer cells (BCCs) transfected with siRNA and plasmid targeting Hh signaling, CD24, and STAT1 were investigated. CD24 siRNA-transfected BCCs demonstrated higher expression of SHH and GLI1, increased anchorage-independent proliferation, enhanced invasiveness and superior tumorigenicity compared with control. Conversely, CD24 forced-expressing BCCs possessed decreased SHH and GLI1 expression, anchorage-independent proliferation, and invasiveness. Suppression of SHH decreased invasiveness through inhibition of matrix metalloproteinase (MMP)-2 expression, GLI1 expression, anchorage-independent proliferation, tumorigenicity, and tumor volume in vivo in CD24 siRNA-transfected BCCs. DNA microarray analysis identified STAT1 as a connection between CD24 and SHH. CD24 siRNA-transfected BCCs with concurrent STAT1 inhibition exhibited decreased SHH expression, invasiveness, anchorage-independent proliferation, tumorigenicity, and tumor volume in vivo. Consistently, STAT1 over-expression induced elevated SHH expression, invasiveness, and anchorage-independent proliferation in BCCs. These results suggest that CD24 suppresses development of a malignant phenotype by down-regulating SHH transcription through STAT1 inhibition.
Project description:This study demonstrates that CD4+Tstr cells contribute to the formation of an immunosuppressive microenvironment. Furthermore, the high expression of TNFα by tumor cells in PNI tissues may promote Schwann cell release of CCL4 chemokine, thereby recruiting additional CD4+T cells and exacerbating PNI progression. Consequently, TNFα monoclonal antibodies may enhance the response to PD-1 monoclonal antibody therapy in patients with neuroinvasive colorectal cancer.
Project description:Pancreatic cancer stem cells (CSCs) have been described as CD24+/CD44+/EpCAM+ or CD133+ cells. However, no study has determined the co-expression of all of these markers in pancreatic ductal adenocarcinoma. Similarly to other combinations of CSC markers, CD24+/ CD44+/EpCAM+/CD133+ phenotype might more accurately identify true pancreatic CSCs. Therefore, we performed a detailed co-expression analysis of CD24, CD44, EpCAM, and CD133 in 3 cell lines derived from primary pancreatic ductal adenocarcinomas (PDACs). Gene expression profiling was applied in order to further investigate the observed differences in proportion of cells that co-expressed CSC markers among the cell lines.
Project description:Tumorigenic breast cancer cells characterized by CD44 expression and low or undetectable CD24 levels (CD44+/CD24-/low) may be resistant to chemotherapy and therefore responsible for cancer relapse. Paired breast cancer core biopsies before and after neoadjuvant chemotherapy or lapatinib were obtained and as single cell suspensions stained using antibodies against CD24, CD44, and lineage markers, and then analyzed by flow cytometry. Mammosphere (MS) formation in culture was compared before and after treatment. Global gene expression differences between cancer cells bearing CD44+/CD24-/low cells and all other sorted cells, and between cancer MS and the primary bulk invasive cancers were analyzed. We report that CD44+/CD24-/low tumorigenic breast cancer cells were intrinsically chemoresistant ─ chemotherapy led to increased CD44+/CD24-/low cells, increased self-renewal capacity on MS assays, and enhanced tumorigeneicity in immunocompromised SCID/Beige mice. Conversely, in patients with HER2 overexpressing tumors, the EGFR/HER2 tyrosine kinase inhibitor, lapatinib decreased CD44+/CD24-/low cells, with the majority of these patients after conventional therapy achieving pathologic complete response, a validated surrogate marker for long-term survival. Gene transcription pathways that underlie chemoresistant, MS-forming CD44+/CD24-/low cells involve genes belonging to stem cell self-renewal, Wnt signaling, and early development pathways. Keywords: two group comparison
Project description:Tumorigenic breast cancer cells characterized by CD44 expression and low or undetectable CD24 levels (CD44+/CD24-/low) may be resistant to chemotherapy and therefore responsible for cancer relapse. Paired breast cancer core biopsies before and after neoadjuvant chemotherapy or lapatinib were obtained and as single cell suspensions stained using antibodies against CD24, CD44, and lineage markers, and then analyzed by flow cytometry. Mammosphere (MS) formation in culture was compared before and after treatment. Global gene expression differences between cancer cells bearing CD44+/CD24-/low cells and all other sorted cells, and between cancer MS and the primary bulk invasive cancers were analyzed. We report that CD44+/CD24-/low tumorigenic breast cancer cells were intrinsically chemoresistant ─ chemotherapy led to increased CD44+/CD24-/low cells, increased self-renewal capacity on MS assays, and enhanced tumorigeneicity in immunocompromised SCID/Beige mice. Conversely, in patients with HER2 overexpressing tumors, the EGFR/HER2 tyrosine kinase inhibitor, lapatinib decreased CD44+/CD24-/low cells, with the majority of these patients after conventional therapy achieving pathologic complete response, a validated surrogate marker for long-term survival. Gene transcription pathways that underlie chemoresistant, MS-forming CD44+/CD24-/low cells involve genes belonging to stem cell self-renewal, Wnt signaling, and early development pathways. Keywords: two group comparison
Project description:In pancreatic cancer the survival rate is low, as the available treatment options usually only extend survival and seldom produce a cure. Drug resistance and disease reoccurrence is the typical reason for death after cancer diagnosis. 5-Fluorouracil (5-FU) is the main chemostatic used in first line therapy. However the majority of the tumors become resistant to treatment. To investigate acquired 5-FU resistance in pancreatic adenocarcinoma, we established chemoresistant monoclonal cell lines from the Panc03.27 cell line by long-term exposure to 5-FU. In addition to increased expression of markers associated with multidrug resistance, the 5-FU resistant clones showed alterations typical of the process of epithelial-to-mesenchymal transition (EMT), including upregulation of mesenchymal markers and increased invasiveness. Microarray analysis revealed the L1CAM pathway as one of the most upregulated pathways in the chemoresistant clones, which was confirmed on RNA and protein levels. Expression of the adhesion molecule L1CAM is associated with a chemoresistant and migratory phenotype of pancreatic cancer. Using esiRNA targeting L1CAM, or by blocking the extracellular part of L1CAM with monoclonal antibodies, we discovered that the increased invasiveness observed in the chemoresistant cells depends on L1CAM. Using esiRNA targeting β-catenin and/or Slug, we discovered that L1CAM expression depends on Slug rather than β-catenin in the 5-FU resistant cells. We demonstrate a functional link between Slug and the expression level of L1CAM in pancreatic cancer cells having undergone EMT following long-term exposure to 5-FU. Our findings provide further insight into the molecular mechanisms leading to a chemoresistant and migratory phenotype in pancreatic cancer cells and indicate the importance of Slug-induced L1CAM in refractory pancreatic cancer.