BACKGROUND: Cancer of the pancreas is the fourth leading cause of cancer death in industrialized countries. In malignancy, actively proliferating cells may be effectively targeted and killed by anti-cancer therapies, ...BACKGROUND: Cancer of the pancreas is the fourth leading cause of cancer death in industrialized countries. In malignancy, actively proliferating cells may be effectively targeted and killed by anti-cancer therapies, but stem cells may survive and support re-growth of the tumor. Thus, new strategies for the treatment of cancer clearly will also have to target cancer stem cells. The goal of the present study was to determine whether pancreatic carcinoma cell growth may be driven by a subpopulation of cancer stem cells. Because previous data implicated ABCG2 and CD133 as stem cell markers in hematopoietic and neural stem/progenitor cells, we analyzed the expression of these two proteins in pancreatic carcinoma cell lines. METHODS: Five established pancreatic adenocarcinoma cell lines were analyzed. Total RNA was isolated and real- time RT-PCR was performed to determine the expression of ABCG2 and CD133. Surface expression of ABCG2 and CD133 was analyzed by flow cytometric analysis. RESULTS: All pancreatic carcinoma cell lines tested expressed significantly higher levels of ABCG2 than non-malignant fibroblasts or two other malignant non- pancreatic cell lines, i.e., SaOS2 osteosarcoma and SKOV3 ovarian cancer. Elevated CD133 expression was found in two out of five pancreatic carcinoma cell lines tested. Using flow cytometric analysis we confirmed surface expression of ABCG2 in all five lines. Yet, CD133 surface expression was detectable in the two cell lines, A818-6 and PancTu1, which exhibited higher mRNA levels.CONCLUSIONS: Two stem cell markers, ABCG2 and CD133 are expressed in pancreatic carcinoma cell lines. ABCG2 and/or CD133 positive cells may represent subpopulation of putative cancer stem cells also in this malignancy. Because cancer stem cells are thought to be responsible for tumor initiation and its recurrence after an initial response to chemotherapy, they may be a very promising target for new drug developments.展开更多
Bone marrow mesenchymal stem cells (BMSCs) have the ability of self-renewaland multi-directional differentiation. Recent reports showed that BMSCs could differentiate intoendocrine cells of pancreas. However, the diff...Bone marrow mesenchymal stem cells (BMSCs) have the ability of self-renewaland multi-directional differentiation. Recent reports showed that BMSCs could differentiate intoendocrine cells of pancreas. However, the differentiation is not efficient enough to produceinsulin-producing cells for the future therapeutic use. Pdx-1 is a crucial regulator for pancreaticdevelopment. Therefore we constructed a eukaryotic expression vector containing Pdx-1 to determinethe effect of Pdx-1 expression on differentiation of BMSCs in vitro. The results showed that BMSCscould self-assemble to form functional pancreatic islet-like structures after differentiation invitro. The proportion of insulin-producing cells differentiated from Pdx-1 +BMSCs was 28.23%+-2.56%,higher than that from BMSCs transfected with vacant vector and Pdx-1'' BMSCs (7.23%+-1.56% and4.08%+-2.69% respectively) by flow cytometry. Immunocytochemical examination also testified theexpression of multiple bate-cells-specific genes such as insulin, glucagons, somatostatin indifferentiated BMSCs. The results also revealed that the expressions of genes mentioned above inPdx-1+BMSCs were higher than that in Pdx-VBMSCs, which was confirmed by Western blotting analysisand RT-PCR. Glucose-inducedinsulin secretion from Pdx-1+BMSCs in 5mmol/L and 25mmol/L glocuse was(56.61 +-4.82) uU/ml and (115.29+-2.56) uU/ml respectively, which were much higher than those fromPdx-1 BMSCs((25.53 +-6.49) uU/mL and (53.26 + 7.56) uU/mL respectively). Grafted animals were ableto maintain their body weight and survive for relatively longer periods of time than hyperglycemicsham-grafted controls, which demonstrated an overall beneficial effect of the grafted cells on thehealth of the animals. These findings thus suggested that exogenous expression of Pdx-1 shouldprovide a promising approach for efficiently producing islet-like cells from BMSCs for the futuretherapeutic use in diabetic patients.展开更多
Obesity is a major health problem and currently is endemic around the world. Obesity is a risk factor for several different types of cancer, significantly promoting cancer incidence, progression, poor prognosis and re...Obesity is a major health problem and currently is endemic around the world. Obesity is a risk factor for several different types of cancer, significantly promoting cancer incidence, progression, poor prognosis and resistance to anti-cancer therapies. The study of this resistance is critical as development of chemoresistance is a serious drawback for the successful and effective drug-based treatments of cancer. There is increasing evidence that augmented adiposity can impact on chemotherapeutic treatment of cancer and the development of resistance to these treatments, particularly through one of its signature mediators, the adipokine leptin. Leptin is a pro-inflammatory, pro-angiogenic and pro-tumorigenic adipokine that has been implicated in many cancers promoting processes such as angiogenesis, metastasis, tumorigenesis and survival/resistance to apoptosis. Several possible mechanisms that could potentially be developed by cancer cells to elicit drug resistance have been suggested in the literature. Here, we summarize and discuss the current state of the literature on the role of obesity and leptin on chemoresistance, particularly as it relates to breast and pancreatic cancers. We focus on the role of leptin and its significance in possibly driving these proposed chemoresistance mechanisms, and examine its effects on cancer cell survival signals and expansion of the cancer stem cell sub-populations.展开更多
Pancreatic cancer(PC) has been one of the deadliest of all cancers, with almost uniform lethality despite aggressive treatment. Recently, there have been important advances in the molecular, pathological and biologica...Pancreatic cancer(PC) has been one of the deadliest of all cancers, with almost uniform lethality despite aggressive treatment. Recently, there have been important advances in the molecular, pathological and biological understandingof pancreatic cancer. Even after the emergence of recent new targeted agents and the use of multiple therapeutic combinations, no treatment option is viable in patients with advanced cancer. Developing novel strategies to target progression of PC is of intense interest. A small population of pancreatic cancer stem cells(CSCs) has been found to be resistant to chemotherapy and radiation therapy. CSCs are believed to be responsible for tumor initiation, progression and metastasis. The CSC research has recently achieved much progress in a variety of solid tumors, including pancreatic cancer to some extent. This leads to focus on understanding the role of pancreatic CSCs. The focus on CSCs may offer new targets for prevention and treatment of this deadly cancer. We review the most salient developments in important areas of pancreatic CSCs. Here, we provide a review of current updates and new insights on the role of CSCs in pancreatic tumor progression with special emphasis on Dcl K1 and Lgr5, signaling pathways altered by CSCs, and the role of CSCs in prevention and treatment of PC.展开更多
Pancreatic ductal adenocarcinoma(PDAC)is one of the most lethal diseases,with an average 5-year survival rate of less than 10%.Unfortunately,the majority of patients have unresectable,locally advanced,or metastatic di...Pancreatic ductal adenocarcinoma(PDAC)is one of the most lethal diseases,with an average 5-year survival rate of less than 10%.Unfortunately,the majority of patients have unresectable,locally advanced,or metastatic disease at the time of diagnosis.Moreover,traditional treatments such as chemotherapy,surgery,and radiation have not been shown to significantly improve survival.Recently,there has been a swift increase in cancer treatments that incorporate immunotherapybased strategies to target all the stepwise events required for tumor initiation and progression.The results in melanoma,non-small-cell lung cancer and renal cell carcinoma are very encouraging.Unfortunately,the application of checkpoint inhibitors,including anti-CTLA4,anti-PD-1,and anti-PD-L1 antibodies,in pancreatic cancer has been disappointing.Many studies have revealed that the PDAC microenvironment supports tumor growth,promotes metastasis and consists of a physical barrier to drug delivery.Combination therapies hold great promise for enhancing immune responses to achieve a better therapeutic effect.In this review,we provide an outline of why pancreatic cancer is so lethal and of the treatment hurdles that exist.Particular emphasis is given to the role of the tumor microenvironment,and some of the latest and most promising studies on immunotherapy in PDAC are also presented.展开更多
BACKGROUND:Emerging evidence suggests that pancreatic adenocarcinoma is hierarchically organized and sustained by pancreatic cancer stem cells.Furthermore,elimination of these cells is possible and therapeutically rel...BACKGROUND:Emerging evidence suggests that pancreatic adenocarcinoma is hierarchically organized and sustained by pancreatic cancer stem cells.Furthermore,elimination of these cells is possible and therapeutically relevant.This study aimed to investigate the expression patterns of pancreatic cancer stem cell surface markers CD44,CD24 and ESA in pancreatic adenocarcinoma cell lines and explore the influence of their local microenvironment.METHODS:Flow cytometry was used to analyze the expression patterns of CD44,CD24 and ESA in five pancreatic adenocarcinoma cell lines (PANC-1,PC-2,MIA-Paca-2,AsPC-1 and BxPC-3).In addition,the capacity for sphereformation in serum-free medium of four cell lines (PANC-1,PC-2,MIA-Paca-2 and BxPC-3) was assessed.Then,the same assays were performed when tumor cell spheres were developed.The role of sonic hedgehog (SHH) in cell spheres from PANC-1 and MIA-Paca-2 were also assessed by RT-PCR.RESULTS:CD44 and CD24 were detected in PANC-1.Only CD44 expression was detected in PC-2,MIA-Paca-2 and AsPC-1.CD44,CD24 and ESA were all detected in BxPC-3.Tumor cell spheres developed in PANC-1 and MIA-Paca-2 in serumfree medium.This was accompanied by an increase in CD24 expression and a decrease in CD44 expression in PANC-1.Interestingly,the expression of CD44 and CD24 returned to initial levels once the medium was changed back from serumfree to serum-containing medium.No significant change in the expression of CD44 was detected in MIA-Paca-2.Furthermore,the relative quantification of SHH mRNA in PANC-1 cell spheres was significantly higher than that in cells cultured in the serum-containing medium.CONCLUSION:The expression patterns of the pancreatic cancer stem cell surface markers CD44,CD24 and ESA were diverse in different pancreatic adenocarcinoma cell lines and changed with their local microenvironment.展开更多
Pancreatic stem cells were isolated and cultured from aborted human fetal pancreases of gestational age 14-20 weeks. They were seeded at a density of 1 × 104 in serum-free media for differentiation into neuron-li...Pancreatic stem cells were isolated and cultured from aborted human fetal pancreases of gestational age 14-20 weeks. They were seeded at a density of 1 × 104 in serum-free media for differentiation into neuron-like cells, expressing β-tubulin III and glial fibrillary acidic protein. These neuron-like cells displayed a synapse-like morphology and appeared to form a neuronal network. Pancreatic stem cells were also seeded at a density of 1 × 105 for differentiation into islet-like cells, expressing insulin and glucagon, with an islet-like morphology. These cells had glucose-stimulated secretion of human insulin and C-peptide. Results suggest that pancreatic stem cells can be differentiated into neuron-like and islet-like cells.展开更多
文摘BACKGROUND: Cancer of the pancreas is the fourth leading cause of cancer death in industrialized countries. In malignancy, actively proliferating cells may be effectively targeted and killed by anti-cancer therapies, but stem cells may survive and support re-growth of the tumor. Thus, new strategies for the treatment of cancer clearly will also have to target cancer stem cells. The goal of the present study was to determine whether pancreatic carcinoma cell growth may be driven by a subpopulation of cancer stem cells. Because previous data implicated ABCG2 and CD133 as stem cell markers in hematopoietic and neural stem/progenitor cells, we analyzed the expression of these two proteins in pancreatic carcinoma cell lines. METHODS: Five established pancreatic adenocarcinoma cell lines were analyzed. Total RNA was isolated and real- time RT-PCR was performed to determine the expression of ABCG2 and CD133. Surface expression of ABCG2 and CD133 was analyzed by flow cytometric analysis. RESULTS: All pancreatic carcinoma cell lines tested expressed significantly higher levels of ABCG2 than non-malignant fibroblasts or two other malignant non- pancreatic cell lines, i.e., SaOS2 osteosarcoma and SKOV3 ovarian cancer. Elevated CD133 expression was found in two out of five pancreatic carcinoma cell lines tested. Using flow cytometric analysis we confirmed surface expression of ABCG2 in all five lines. Yet, CD133 surface expression was detectable in the two cell lines, A818-6 and PancTu1, which exhibited higher mRNA levels.CONCLUSIONS: Two stem cell markers, ABCG2 and CD133 are expressed in pancreatic carcinoma cell lines. ABCG2 and/or CD133 positive cells may represent subpopulation of putative cancer stem cells also in this malignancy. Because cancer stem cells are thought to be responsible for tumor initiation and its recurrence after an initial response to chemotherapy, they may be a very promising target for new drug developments.
基金financially supported by the National Natural Science Foundation of China(Grant No.30200128).
文摘Bone marrow mesenchymal stem cells (BMSCs) have the ability of self-renewaland multi-directional differentiation. Recent reports showed that BMSCs could differentiate intoendocrine cells of pancreas. However, the differentiation is not efficient enough to produceinsulin-producing cells for the future therapeutic use. Pdx-1 is a crucial regulator for pancreaticdevelopment. Therefore we constructed a eukaryotic expression vector containing Pdx-1 to determinethe effect of Pdx-1 expression on differentiation of BMSCs in vitro. The results showed that BMSCscould self-assemble to form functional pancreatic islet-like structures after differentiation invitro. The proportion of insulin-producing cells differentiated from Pdx-1 +BMSCs was 28.23%+-2.56%,higher than that from BMSCs transfected with vacant vector and Pdx-1'' BMSCs (7.23%+-1.56% and4.08%+-2.69% respectively) by flow cytometry. Immunocytochemical examination also testified theexpression of multiple bate-cells-specific genes such as insulin, glucagons, somatostatin indifferentiated BMSCs. The results also revealed that the expressions of genes mentioned above inPdx-1+BMSCs were higher than that in Pdx-VBMSCs, which was confirmed by Western blotting analysisand RT-PCR. Glucose-inducedinsulin secretion from Pdx-1+BMSCs in 5mmol/L and 25mmol/L glocuse was(56.61 +-4.82) uU/ml and (115.29+-2.56) uU/ml respectively, which were much higher than those fromPdx-1 BMSCs((25.53 +-6.49) uU/mL and (53.26 + 7.56) uU/mL respectively). Grafted animals were ableto maintain their body weight and survive for relatively longer periods of time than hyperglycemicsham-grafted controls, which demonstrated an overall beneficial effect of the grafted cells on thehealth of the animals. These findings thus suggested that exogenous expression of Pdx-1 shouldprovide a promising approach for efficiently producing islet-like cells from BMSCs for the futuretherapeutic use in diabetic patients.
基金Supported by Department of Defense(DOD)Congressionally Direct Medical Research Program(CDMRP)+3 种基金No.W81XWH-13-1-0382National Institute of Health(NIH)/National Cancer Institute(NCI),No.1R41CA183399-01APilot Project Award from MSM(Morehouse School of Medicine)/Tuskegee University/University of Alabama in Birmingham(UAB)Cancer Center partnership,No.5U54CA118638the National Institute on Minority Health and Health Disparities(NIMHD)of NIH,No.5S21MD00101
文摘Obesity is a major health problem and currently is endemic around the world. Obesity is a risk factor for several different types of cancer, significantly promoting cancer incidence, progression, poor prognosis and resistance to anti-cancer therapies. The study of this resistance is critical as development of chemoresistance is a serious drawback for the successful and effective drug-based treatments of cancer. There is increasing evidence that augmented adiposity can impact on chemotherapeutic treatment of cancer and the development of resistance to these treatments, particularly through one of its signature mediators, the adipokine leptin. Leptin is a pro-inflammatory, pro-angiogenic and pro-tumorigenic adipokine that has been implicated in many cancers promoting processes such as angiogenesis, metastasis, tumorigenesis and survival/resistance to apoptosis. Several possible mechanisms that could potentially be developed by cancer cells to elicit drug resistance have been suggested in the literature. Here, we summarize and discuss the current state of the literature on the role of obesity and leptin on chemoresistance, particularly as it relates to breast and pancreatic cancers. We focus on the role of leptin and its significance in possibly driving these proposed chemoresistance mechanisms, and examine its effects on cancer cell survival signals and expansion of the cancer stem cell sub-populations.
基金In part by Kerley Cade Endowed Chair(Chinthalapally V Rao),University of Oklahoma Health Sciences Centerin part support from the National Cancer Institute,No.5R03CA181584-02(Altaf Mohammed)
文摘Pancreatic cancer(PC) has been one of the deadliest of all cancers, with almost uniform lethality despite aggressive treatment. Recently, there have been important advances in the molecular, pathological and biological understandingof pancreatic cancer. Even after the emergence of recent new targeted agents and the use of multiple therapeutic combinations, no treatment option is viable in patients with advanced cancer. Developing novel strategies to target progression of PC is of intense interest. A small population of pancreatic cancer stem cells(CSCs) has been found to be resistant to chemotherapy and radiation therapy. CSCs are believed to be responsible for tumor initiation, progression and metastasis. The CSC research has recently achieved much progress in a variety of solid tumors, including pancreatic cancer to some extent. This leads to focus on understanding the role of pancreatic CSCs. The focus on CSCs may offer new targets for prevention and treatment of this deadly cancer. We review the most salient developments in important areas of pancreatic CSCs. Here, we provide a review of current updates and new insights on the role of CSCs in pancreatic tumor progression with special emphasis on Dcl K1 and Lgr5, signaling pathways altered by CSCs, and the role of CSCs in prevention and treatment of PC.
文摘Pancreatic ductal adenocarcinoma(PDAC)is one of the most lethal diseases,with an average 5-year survival rate of less than 10%.Unfortunately,the majority of patients have unresectable,locally advanced,or metastatic disease at the time of diagnosis.Moreover,traditional treatments such as chemotherapy,surgery,and radiation have not been shown to significantly improve survival.Recently,there has been a swift increase in cancer treatments that incorporate immunotherapybased strategies to target all the stepwise events required for tumor initiation and progression.The results in melanoma,non-small-cell lung cancer and renal cell carcinoma are very encouraging.Unfortunately,the application of checkpoint inhibitors,including anti-CTLA4,anti-PD-1,and anti-PD-L1 antibodies,in pancreatic cancer has been disappointing.Many studies have revealed that the PDAC microenvironment supports tumor growth,promotes metastasis and consists of a physical barrier to drug delivery.Combination therapies hold great promise for enhancing immune responses to achieve a better therapeutic effect.In this review,we provide an outline of why pancreatic cancer is so lethal and of the treatment hurdles that exist.Particular emphasis is given to the role of the tumor microenvironment,and some of the latest and most promising studies on immunotherapy in PDAC are also presented.
基金supported by a grant from the National Natural Science Foundation of China(30801100)
文摘BACKGROUND:Emerging evidence suggests that pancreatic adenocarcinoma is hierarchically organized and sustained by pancreatic cancer stem cells.Furthermore,elimination of these cells is possible and therapeutically relevant.This study aimed to investigate the expression patterns of pancreatic cancer stem cell surface markers CD44,CD24 and ESA in pancreatic adenocarcinoma cell lines and explore the influence of their local microenvironment.METHODS:Flow cytometry was used to analyze the expression patterns of CD44,CD24 and ESA in five pancreatic adenocarcinoma cell lines (PANC-1,PC-2,MIA-Paca-2,AsPC-1 and BxPC-3).In addition,the capacity for sphereformation in serum-free medium of four cell lines (PANC-1,PC-2,MIA-Paca-2 and BxPC-3) was assessed.Then,the same assays were performed when tumor cell spheres were developed.The role of sonic hedgehog (SHH) in cell spheres from PANC-1 and MIA-Paca-2 were also assessed by RT-PCR.RESULTS:CD44 and CD24 were detected in PANC-1.Only CD44 expression was detected in PC-2,MIA-Paca-2 and AsPC-1.CD44,CD24 and ESA were all detected in BxPC-3.Tumor cell spheres developed in PANC-1 and MIA-Paca-2 in serumfree medium.This was accompanied by an increase in CD24 expression and a decrease in CD44 expression in PANC-1.Interestingly,the expression of CD44 and CD24 returned to initial levels once the medium was changed back from serumfree to serum-containing medium.No significant change in the expression of CD44 was detected in MIA-Paca-2.Furthermore,the relative quantification of SHH mRNA in PANC-1 cell spheres was significantly higher than that in cells cultured in the serum-containing medium.CONCLUSION:The expression patterns of the pancreatic cancer stem cell surface markers CD44,CD24 and ESA were diverse in different pancreatic adenocarcinoma cell lines and changed with their local microenvironment.
基金supported by the Science and Technology Plan Project of Yantai City (Transplantation of pancreatic islet cells induced from human embryonic stem cells into diabetic animals in vitro), No. 2008142-9
文摘Pancreatic stem cells were isolated and cultured from aborted human fetal pancreases of gestational age 14-20 weeks. They were seeded at a density of 1 × 104 in serum-free media for differentiation into neuron-like cells, expressing β-tubulin III and glial fibrillary acidic protein. These neuron-like cells displayed a synapse-like morphology and appeared to form a neuronal network. Pancreatic stem cells were also seeded at a density of 1 × 105 for differentiation into islet-like cells, expressing insulin and glucagon, with an islet-like morphology. These cells had glucose-stimulated secretion of human insulin and C-peptide. Results suggest that pancreatic stem cells can be differentiated into neuron-like and islet-like cells.
