INTRODUCTIONDevelopment of drug-resistance to chemotherapyand subsequent metastasis of tumor are primarilyresponsible for treatment failure and the death fromcancer. There have been many previous studies onthe relatio...INTRODUCTIONDevelopment of drug-resistance to chemotherapyand subsequent metastasis of tumor are primarilyresponsible for treatment failure and the death fromcancer. There have been many previous studies onthe relationship between expression of multidrugresistance (MDR) phenotype P-glycoprotein (P-gp)and the malignant properties of tumors, but theresults are often conflicting[1-8]. The difference intumor types or MDR phenotype induced by specificagents might account for this discrepancy. Taxotere(TXT), a member of the family of taxanes, hasantitumor activity through its effect of promotingthe polymerization of tubulin[9,10].展开更多
BACKGROUND: Pancreatic cancer is one of the most aggressive malignancies, and has a poor prognosis. Despite efforts made in multiple fields, there has been little success in improving the disease-free survival rate of...BACKGROUND: Pancreatic cancer is one of the most aggressive malignancies, and has a poor prognosis. Despite efforts made in multiple fields, there has been little success in improving the disease-free survival rate of patients. This study was undertaken to investigate the effectiveness and feasibility of using intra-tumoral injection of ricin-loaded thermosensitive hydrogel for treatment of pancreatic cancer xenografts, attempting to develop a new treatment for human pancreatic cancer. METHODS: BALB/c-(nu/nu) nude mice were inoculated subcutaneously in the right flank with the human pancreatic cancer cells, SW1990. Fourteen days after inoculation, 32 mice, bearing tumors of volume 1.5-2.0 cm(3), were randomly assigned to one of four groups, and given an intra-tumoral injection of: (1) saline; (2) 23% w/w thermosensitive hydrogel alone; (3) ricin, 10 mu g/kg; or (4) 10 mu g/kg ricin loaded in thermosensitive hydrogel. On day 14 after administration, the tumors were excised to calculate the inhibition rate of tumor growth and perform histopathological examination. Tumor cell apoptosis was detected by flow cytometry, and RT-PCR was performed to evaluate the mRNA expression levels of Bc12 and Bax. RESULTS: Intra-tumoral injection of ricin-loaded thermosensitive hydrogel resulted in remarkable control of tumor growth. The tumor became necrotic by day 14 after administration. The histological results clearly confirmed that the tumor cells were lysed. The percentage of apoptotic cells detected by flow cytometry was higher in the ricin hydrogel group than in the other groups. Semi-quantitative RT-PCR revealed that the mRNA expression level of Bc12 was down-regulated whereas Bax was upregulated. CONCLUSIONS: Intra-tumoral injection of ricin-loaded thermosensitive hydrogel may provide an effective approach for interstitial chemotherapy in pancreatic cancer. Inducing apoptosis by downregulating Bcl2 expression and upregulating Bax expression may be a key molecular mechanism.展开更多
The outlook for patients with pancreatic cancer has been grim. There have been major advances in the surgical treatment of pancreatic cancer, leading to a dramatic reduction in post-operative mortality from the develo...The outlook for patients with pancreatic cancer has been grim. There have been major advances in the surgical treatment of pancreatic cancer, leading to a dramatic reduction in post-operative mortality from the development of high volume specialized centres. This stimulated the study of adjuvant and neoadjuvant treatments in pancreatic cancer including chemoradiotherapy and chemotherapy. Initial protocols have been based on the original but rather small GITSG study first reported in 1985. There have been two large European trials totalling over 600 patients (EORTC and ESPAC-1) that do not support the use of chemoradiation as adjuvant therapy. A second major finding from the ESPAC-1 trial (541 patients randomized) was some but not conclusive evidence for a survival benefit associated with chemotherapy. A third major finding from the ESPAC-1 trial was that the quality of life was not affected by the use of adjuvant treatments compared to surgery alone. The ESPAC-3 trial aims to assess the definitive use of adjuvant chemotherapy in a randomized controlled trial of 990 patients.展开更多
AIM: To investigate the specific mechanisms of intrinsic and acquired resistance to taxotere (TXT) in pancreatic adenocarcinoma (PAC). METHODS: MTT assay was used to detect the sensitivity of PAC cell line SUIT-2 and ...AIM: To investigate the specific mechanisms of intrinsic and acquired resistance to taxotere (TXT) in pancreatic adenocarcinoma (PAC). METHODS: MTT assay was used to detect the sensitivity of PAC cell line SUIT-2 and its sublines (S-007, S-013, S-020, S-028 and TXT selected SUIT-2 cell line, S2/TXT) to TXT. Mdr1 (P-gp), multidrug resistance associated protein (MRP), lung resistance protein (LRP) and beta-tubulin isotype gene expressions were detected by RT-PCR. The functionality of P-gp and MRP was tested using their specific blocker verapamil (Ver) and indomethacin (IMC), respectively. The transporter activity of P-gp was also confirmed by Rhodamine 123 accumulation assay. RESULTS: S-020 and S2/TXT were found to be significantly resistant to TXT(19 and 9.5-fold to their parental cell line SUIT-2, respectively). RT-PCR demonstrated strong expression of Mdr1 in these two cell lines, but weaker expression or no expression in other cells lines. MRP and LRP expressions were found in most of these cell lines. The TXT-resistance in S2-020 and S2/TXT could be reversed almost completely by Ver, but not by IMC. Flow cytometry showed that Ver increased the accumulation of Rhodamine-123 in these two cell lines. Compared with S-020 and SUIT-2, the levels of beta-tubulin isotype II, III expressions in S-2/TXT were increased remarkably. CONCLUSION: The both intrinsic and acquired TXT-related drug resistance in these PAC cell lines is mainly mediated by P-gp, but had no relationship to MRP and LRP expressions. The increases of beta-tubulin isotype II, III might be collateral changes that occur when the SUIT-2 cells are treated with TXT.展开更多
AIM:There are conflicting data about p53 function on cellular sensitivity to the cytotoxic action of 5-fluorouracil (5-FU). Therefore the objective of this study was to determine the combined effects of adenovirus-med...AIM:There are conflicting data about p53 function on cellular sensitivity to the cytotoxic action of 5-fluorouracil (5-FU). Therefore the objective of this study was to determine the combined effects of adenovirus-mediated wild-type (wt) p53 gene transfer and 5-FU chemotherapy on pancreatic cancer cells with different p53 gene status. METHODS:Human pancreatic cancer cell lines Capan-1^(p53mut), Capan-2^(p53wt),FAMPAC^(p53mut),PANC1^(p53mut),and rat pancreatic cancer cell lines AS^(p53wt) and DSL6A^(p53null) were used for in vitro studies.Following infection with different ratios of Ad- p53-particles (MOI) in combination with 5-FU,proliferation of tumor cells and apoptosis were quantified by cell proliferation assay (WST-1) and FACS (PI-staining).In addition,DSL6A syngeneic pancreatic tumor cells were inoculated subcutaneously in to Lewis rats for in vivo studies. Tumor size,apoptosis (TUNEL) and survival were determined. RESULTS:Ad-p53 gene transfer combined with 5-FU significantly inhibited tumor cell proliferation and substantially enhanced apoptosis in all four cell lines with an alteration in the p53 gene compared to those two cell lines containing wt-p53.In vivo experiments showed the most effective tumor regression in animals treated with Ad-p53 plus 5-FU.Both in vitro and in vivo analyses revealed that a sublethal dose of Ad-p53 augmented the apoptotic response induced by 5-FU. CONCLUSION:Our results suggest that Ad-p53 may synergistically enhance 5-FU-chemosensitivity most strikingly in pancreatic cancer cells lacking p53 function.These findings illustrate that the anticancer efficacy of this combination treatment is dependent on the p53 gene status of the target tumor cells.展开更多
Objective： To investigate the relationship between extracellular signal-regulated kinase （ERK） pathway, multidrug resistance gene （mdr-1）, ribonucleotide recluctase M1 （RRM1） gene and their roles in gemcitabine...Objective： To investigate the relationship between extracellular signal-regulated kinase （ERK） pathway, multidrug resistance gene （mdr-1）, ribonucleotide recluctase M1 （RRM1） gene and their roles in gemcitabine （GEM） chemoresistance in pancreatic cancer cell line SW1990. Methods： The GEM-resistance cell model was constructed by a stepwise method. Immunohistochemistry was used to measure the expression of ERK protein （ERK1/2） in the established cell strains in a semiquantitative way. The mRNA expression of mdr-1 and RRM1 were detected by RT-PCR. MTT assay was performed to determine the IC50 value. Results： The established GEM-resistant cell strains were able to gain stable growth and passage ability in the medium contained different concentration levels of GEM （0, 30, 60, 100, 150 and 200 nmol/L）. The expression of ERK protein, mdr-1 and RRM1 gene were elevated accompanied by the increase of GEM concentration. There was a highly positive correlation between mdr-1, RRM1 expression and GEM-resistanca level （r = 0.960, P = 0.002 and r = 0.966, P = 0.002）. The expression of ERK protein also correlated with the mdr-1 and RRM1 level （r = -0.943, P = 0.005 and r = -0.883, P = 0.02）. At the GEM-resistance level of 200 nmol/L, the grey scale value of ERK1/2 was 164.22 ±13.17, mdr-1/β-actin and RRM1/β-actin were 1.41 ±0.04 and 1.45 ± 0.18, respectively; after treated with ERK pathway inhibitor U0126, these values synchronously decreased to 186.85 ± 13.14, 0.2 3± 0.02 and 0.21 ± 0.03, respectively; inversely, the ERK1/2 grey scale value was 106.55 ± 16.45, mdr-l/β-actin and RRMl/β-actin were 1.50± 0.07 and 1.52 ± 0.12, respectively, which presented a tendency of synchronously increase after treated with ERK pathway activator EGF. The IC50 values in GEM-resistant cells of 0 nmol/L and 200 nmol/L levels were 4.104 and 10.20, respectively. After treated with U0126, these values decreased to 3.26 and 4.50, respectively; while treated with EGF, the IC50 values increased to 8.89 and 17.17, respectively. Conclusion： The ERK pathway may induce the GEM-chemoresistance in pancreatic cell line SW1990 through the participation in the regulation of the mdr-1 and RRM1 gene expression.展开更多
基金Supported in part by phone-Poulenc Rorer Pharmaceuticals INC
文摘INTRODUCTIONDevelopment of drug-resistance to chemotherapyand subsequent metastasis of tumor are primarilyresponsible for treatment failure and the death fromcancer. There have been many previous studies onthe relationship between expression of multidrugresistance (MDR) phenotype P-glycoprotein (P-gp)and the malignant properties of tumors, but theresults are often conflicting[1-8]. The difference intumor types or MDR phenotype induced by specificagents might account for this discrepancy. Taxotere(TXT), a member of the family of taxanes, hasantitumor activity through its effect of promotingthe polymerization of tubulin[9,10].
文摘BACKGROUND: Pancreatic cancer is one of the most aggressive malignancies, and has a poor prognosis. Despite efforts made in multiple fields, there has been little success in improving the disease-free survival rate of patients. This study was undertaken to investigate the effectiveness and feasibility of using intra-tumoral injection of ricin-loaded thermosensitive hydrogel for treatment of pancreatic cancer xenografts, attempting to develop a new treatment for human pancreatic cancer. METHODS: BALB/c-(nu/nu) nude mice were inoculated subcutaneously in the right flank with the human pancreatic cancer cells, SW1990. Fourteen days after inoculation, 32 mice, bearing tumors of volume 1.5-2.0 cm(3), were randomly assigned to one of four groups, and given an intra-tumoral injection of: (1) saline; (2) 23% w/w thermosensitive hydrogel alone; (3) ricin, 10 mu g/kg; or (4) 10 mu g/kg ricin loaded in thermosensitive hydrogel. On day 14 after administration, the tumors were excised to calculate the inhibition rate of tumor growth and perform histopathological examination. Tumor cell apoptosis was detected by flow cytometry, and RT-PCR was performed to evaluate the mRNA expression levels of Bc12 and Bax. RESULTS: Intra-tumoral injection of ricin-loaded thermosensitive hydrogel resulted in remarkable control of tumor growth. The tumor became necrotic by day 14 after administration. The histological results clearly confirmed that the tumor cells were lysed. The percentage of apoptotic cells detected by flow cytometry was higher in the ricin hydrogel group than in the other groups. Semi-quantitative RT-PCR revealed that the mRNA expression level of Bc12 was down-regulated whereas Bax was upregulated. CONCLUSIONS: Intra-tumoral injection of ricin-loaded thermosensitive hydrogel may provide an effective approach for interstitial chemotherapy in pancreatic cancer. Inducing apoptosis by downregulating Bcl2 expression and upregulating Bax expression may be a key molecular mechanism.
文摘The outlook for patients with pancreatic cancer has been grim. There have been major advances in the surgical treatment of pancreatic cancer, leading to a dramatic reduction in post-operative mortality from the development of high volume specialized centres. This stimulated the study of adjuvant and neoadjuvant treatments in pancreatic cancer including chemoradiotherapy and chemotherapy. Initial protocols have been based on the original but rather small GITSG study first reported in 1985. There have been two large European trials totalling over 600 patients (EORTC and ESPAC-1) that do not support the use of chemoradiation as adjuvant therapy. A second major finding from the ESPAC-1 trial (541 patients randomized) was some but not conclusive evidence for a survival benefit associated with chemotherapy. A third major finding from the ESPAC-1 trial was that the quality of life was not affected by the use of adjuvant treatments compared to surgery alone. The ESPAC-3 trial aims to assess the definitive use of adjuvant chemotherapy in a randomized controlled trial of 990 patients.
基金Supported in part by Phne-Poulenc Rorer Pharmaceuticals INC.
文摘AIM: To investigate the specific mechanisms of intrinsic and acquired resistance to taxotere (TXT) in pancreatic adenocarcinoma (PAC). METHODS: MTT assay was used to detect the sensitivity of PAC cell line SUIT-2 and its sublines (S-007, S-013, S-020, S-028 and TXT selected SUIT-2 cell line, S2/TXT) to TXT. Mdr1 (P-gp), multidrug resistance associated protein (MRP), lung resistance protein (LRP) and beta-tubulin isotype gene expressions were detected by RT-PCR. The functionality of P-gp and MRP was tested using their specific blocker verapamil (Ver) and indomethacin (IMC), respectively. The transporter activity of P-gp was also confirmed by Rhodamine 123 accumulation assay. RESULTS: S-020 and S2/TXT were found to be significantly resistant to TXT(19 and 9.5-fold to their parental cell line SUIT-2, respectively). RT-PCR demonstrated strong expression of Mdr1 in these two cell lines, but weaker expression or no expression in other cells lines. MRP and LRP expressions were found in most of these cell lines. The TXT-resistance in S2-020 and S2/TXT could be reversed almost completely by Ver, but not by IMC. Flow cytometry showed that Ver increased the accumulation of Rhodamine-123 in these two cell lines. Compared with S-020 and SUIT-2, the levels of beta-tubulin isotype II, III expressions in S-2/TXT were increased remarkably. CONCLUSION: The both intrinsic and acquired TXT-related drug resistance in these PAC cell lines is mainly mediated by P-gp, but had no relationship to MRP and LRP expressions. The increases of beta-tubulin isotype II, III might be collateral changes that occur when the SUIT-2 cells are treated with TXT.
文摘AIM:There are conflicting data about p53 function on cellular sensitivity to the cytotoxic action of 5-fluorouracil (5-FU). Therefore the objective of this study was to determine the combined effects of adenovirus-mediated wild-type (wt) p53 gene transfer and 5-FU chemotherapy on pancreatic cancer cells with different p53 gene status. METHODS:Human pancreatic cancer cell lines Capan-1^(p53mut), Capan-2^(p53wt),FAMPAC^(p53mut),PANC1^(p53mut),and rat pancreatic cancer cell lines AS^(p53wt) and DSL6A^(p53null) were used for in vitro studies.Following infection with different ratios of Ad- p53-particles (MOI) in combination with 5-FU,proliferation of tumor cells and apoptosis were quantified by cell proliferation assay (WST-1) and FACS (PI-staining).In addition,DSL6A syngeneic pancreatic tumor cells were inoculated subcutaneously in to Lewis rats for in vivo studies. Tumor size,apoptosis (TUNEL) and survival were determined. RESULTS:Ad-p53 gene transfer combined with 5-FU significantly inhibited tumor cell proliferation and substantially enhanced apoptosis in all four cell lines with an alteration in the p53 gene compared to those two cell lines containing wt-p53.In vivo experiments showed the most effective tumor regression in animals treated with Ad-p53 plus 5-FU.Both in vitro and in vivo analyses revealed that a sublethal dose of Ad-p53 augmented the apoptotic response induced by 5-FU. CONCLUSION:Our results suggest that Ad-p53 may synergistically enhance 5-FU-chemosensitivity most strikingly in pancreatic cancer cells lacking p53 function.These findings illustrate that the anticancer efficacy of this combination treatment is dependent on the p53 gene status of the target tumor cells.
文摘Objective： To investigate the relationship between extracellular signal-regulated kinase （ERK） pathway, multidrug resistance gene （mdr-1）, ribonucleotide recluctase M1 （RRM1） gene and their roles in gemcitabine （GEM） chemoresistance in pancreatic cancer cell line SW1990. Methods： The GEM-resistance cell model was constructed by a stepwise method. Immunohistochemistry was used to measure the expression of ERK protein （ERK1/2） in the established cell strains in a semiquantitative way. The mRNA expression of mdr-1 and RRM1 were detected by RT-PCR. MTT assay was performed to determine the IC50 value. Results： The established GEM-resistant cell strains were able to gain stable growth and passage ability in the medium contained different concentration levels of GEM （0, 30, 60, 100, 150 and 200 nmol/L）. The expression of ERK protein, mdr-1 and RRM1 gene were elevated accompanied by the increase of GEM concentration. There was a highly positive correlation between mdr-1, RRM1 expression and GEM-resistanca level （r = 0.960, P = 0.002 and r = 0.966, P = 0.002）. The expression of ERK protein also correlated with the mdr-1 and RRM1 level （r = -0.943, P = 0.005 and r = -0.883, P = 0.02）. At the GEM-resistance level of 200 nmol/L, the grey scale value of ERK1/2 was 164.22 ±13.17, mdr-1/β-actin and RRM1/β-actin were 1.41 ±0.04 and 1.45 ± 0.18, respectively; after treated with ERK pathway inhibitor U0126, these values synchronously decreased to 186.85 ± 13.14, 0.2 3± 0.02 and 0.21 ± 0.03, respectively; inversely, the ERK1/2 grey scale value was 106.55 ± 16.45, mdr-l/β-actin and RRMl/β-actin were 1.50± 0.07 and 1.52 ± 0.12, respectively, which presented a tendency of synchronously increase after treated with ERK pathway activator EGF. The IC50 values in GEM-resistant cells of 0 nmol/L and 200 nmol/L levels were 4.104 and 10.20, respectively. After treated with U0126, these values decreased to 3.26 and 4.50, respectively; while treated with EGF, the IC50 values increased to 8.89 and 17.17, respectively. Conclusion： The ERK pathway may induce the GEM-chemoresistance in pancreatic cell line SW1990 through the participation in the regulation of the mdr-1 and RRM1 gene expression.
