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Selwyn M Vickers

Publications and source records attributed to Selwyn M Vickers.

34 records · Page 2Linked to original sources
PubMed2003

Differential responses by pancreatic carcinoma cell lines to prolonged exposure to Erbitux (IMC-C225) anti-EGFR antibody.

BACKGROUND: Pancreatic cancer remains a devastating disease, with 95% of all patients diagnosed with the disease dying within 2 years. The combined therapy using Erbitux, gemcitabine, and radiation caused complete tumor regression using a nude mouse model inoculated with pancreatic MiaPaCa-2 cells but only a delay in tumor growth with BxPC-3. We investigated the effect of prolonged Erbitux treatment to the sensitivity to gemcitabine and/or radiation and the epidermal growth factor receptor (EGFR) signal transduction pathway. METHODS: MiaPaCa-2 and BxPC-3 cells were cultured with or without Erbitux for 6 weeks. Cells were then treated with gemcitabine and/or radiation, harvested 48 h after treatment, and counted. Differences in EGFR expression after exposure to Erbitux were analyzed by FACS. Internalization rates of EGFR induced by Erbitux on these cell lines were determined using 125I-EGF binding assay after removal of Erbitux by acidic wash. Cell lysates were harvested after cells were stimulated with EGF, FGF, or IGF-1 respectively, and EGFR was immunoprecipitated using Erbitux. Samples were separated using SDS-PAGE and transferred to PVDF membrane. The membranes were probed with antibody against human growth factor receptor binding protein (Grb2) to detect the association of this Ras-MAPK upstream adaptor protein to EGFR. Cell lysates were also separated with SDS-PAGE and probed with rabbit anti-human PARP after samples were transferred to PVDF membrane. Expression of BAX and Bcl-(XL) were probed in the cells treated with or without Erbitux. RESULTS: Proliferation assays indicated that prolonged exposure to Erbitux increased the sensitivities of MiaPaCa-2 to gemcitabine and radiation therapy (41 +/- 16% vs 52 +/- 9% for gemcitation, 28 +/- 9 vs 39 +/- 9% for combination; P = 0.015) but not for BxPC-3. FACS analysis showed that the expressed EGFR level decreased by about 42% on MiaPaCa 2 whereas no loss was seen on BxPC-3. Expression of BAX was upregulated on MiaPaCa-2. Poly (ADP-ribose) polymerase cleavage indicated the killing was mediated by apoptosis. Immunoblots showed that Grb2 was co-immunoprecipitated with EGFR after EGF stimulation. Incubation with Erbitux blocked Grb2 binding in MiaPaCa-2 but not BxPC 3. FGF transactivated EGFR down stream Ras-MAPK in the presence or absence of Erbitux. Internalization of EGFR induced by Erbitux did not differ between MiaPaCa-2 and BxPC-3. CONCLUSIONS: 1) Association of Grb2 to EGFR in BxPC-3 induced by EGF in the presence of Erbitux indicates an alternate pathway of Ras-MAPK activation, which may be related with the tumor resistance to treatment; 2) transactivation of EGFR downstream Ras-MAPK pathway by FGF contributes the resistance to treatment; and 3) downregulation of EGFR may increase the response to therapy.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Laparoscopic vs conventional ileocolectomy for primary Crohn disease.

HYPOTHESIS: Laparoscopic ileocolectomy can reduce the length of hospital stay and hospital charges compared with conventional surgery in the treatment of primary Crohn disease. DESIGN: Nonrandomized, comparative, retrospective analysis of a prospective database. SETTING: University hospital tertiary care center for inflammatory bowel disease. PATIENTS: Forty patients, 20 in the laparoscopic group (group A) and 20 in the conventional group (group B). INTERVENTION: From July 1, 1996, to June 30, 2001, we collected data on the following demographic clinical end points: age, sex, duration of disease, preoperative medical treatment, previous abdominal surgery, procedure performed, conversions to open surgery, operating time, number of trocars used, size of incision, blood loss, time to resolution of ileus, time to starting solid food diet, duration of hospital stay, hospital charges, morbidity, and mortality. MAIN OUTCOME MEASURES: Surgical results, length of hospital stay, hospital charges, and recurrences. RESULTS: The mean age of the patients was 34.7 years (range, 20-68 years) in group A vs 40.0 years (range, 18-75 years) in group B. The male-female ratio was 1:2 in group A vs 1:1 in group B. The morbidity was 5% in group B. There was no mortality. Operating time was longer in group A (mean, 145.0 minutes; range, 45-270 minutes) compared with group B (mean, 133.5 minutes; range, 98-177 minutes) (P =.36). Blood loss was significantly higher in group B (mean, 265.5 mL; range, 100-400 mL) compared with group A (77.2 mL; range, 25-350 mL) (P<.001). Also, the size of the incision was significantly longer in group B (mean, 13.5 cm; range, 8-18 cm) compared with group A (mean, 5.5 cm; range, 3-12 cm) (P<.001). Bowel function returned more quickly in the laparoscopic group vs the conventional group in terms of return of bowel movements (1.70 vs 2.63 days) (P<.001) and resumption of a regular diet (1.35 vs 2.73 days) (P<.001). The mean length of stay was significantly shorter in the laparoscopic group (4.25 days) vs the conventional group (8.25 days) (P<.001). The mean hospital charges were US $9614 in group A vs US $17 079 in group B (P<.05). The mean follow-up was 17.2 months in group A (range, 2.3-59.9 months) vs 18.7 months in group B (range, 1.0-37.5 months). CONCLUSIONS: Laparoscopic-assisted ileocolectomy for primary Crohn disease of the terminal ileum and/or cecum is safe and successful in most cases. Laparoscopic surgery for Crohn disease should be considered as the preferred operative approach for primary resections.

Adolescent↗
PubMed2003

Infectivity enhanced, cyclooxygenase-2 promoter-based conditionally replicative adenovirus for pancreatic cancer.

BACKGROUND AND AIMS: Pancreatic cancer is one of the most aggressive human malignancies. Conditionally replicative adenoviruses (CRAds) have shown some promise in the treatment of cancers. However, to date, their application for pancreatic cancer has met several obstacles: one is lack of a good control element to regulate replication, and the other is relatively low adenoviral infectivity. Thus, we constructed infectivity enhanced cyclooxygenase (COX)-2 promoter-based CRAds to develop a safe and effective therapeutic modality. METHODS: The CRAds were designed to achieve COX-2 promoter-controlled E1 expression for regulated replication (COX-2 CRAds). The infectivity-enhanced CRAds also have an RGD-4C motif in the adenoviral fiber-knob region. The selectivity and efficacy of these constructs were analyzed with cell lines in vitro. The in vivo therapeutic effect and viral replication were analyzed with a xenograft model. Pathology of the major organs and E1 RNA levels in the liver were also studied after systemic administration. RESULTS: The COX-2 CRAds showed a selective cytocidal effect in vitro in COX-2-positive cells and killed most of the pancreatic cancer cells. In vivo, intratumoral administration of the infectivity-enhanced COX-2 CRAds (10(9) particles) showed a strong antitumor effect comparable to wild-type virus, whereas the COX-2 CRAds without infectivity enhancement showed a limited effect. Viral replication was confirmed in the xenograft tumors. Systemic administration did not cause any detectable toxicity; the E1 RNA level in the liver after COX-2 CRAd administration was minimal. CONCLUSIONS: Infectivity-enhanced COX-2 CRAd is a promising agent for the treatment of pancreatic cancer.

Adenoviridae↗
PubMed2003

Endoscopic ultrasound-guided fine needle aspiration biopsy of patients with suspected pancreatic cancer: diagnostic accuracy and acute and 30-day complications.

OBJECTIVES: The aims of this study were to evaluate the diagnostic accuracy of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in patients with suspected pancreatic cancer, and to assess immediate, acute, and 30-day complications related to EUS-FNA. METHODS: All patients with suspected pancreatic cancer were prospectively evaluated. A single gastroenterologist performed all EUS-FNAs in the presence of a cytopathologist. Immediate complications were evaluated in all patients. An experienced nurse called patients 24-72 h and 30 days after the procedure. Reference standard for the classification of the final diagnosis included: surgery (n = 48), clinical or imaging follow-up (n = 63), or death from the disease (n = 47). RESULTS: A total of 158 patients (mean age 62.3 yr) underwent EUS-FNA during the study period. The mean tumor size was 32 x 26 mm. The median number of passes was three (range one to 10). Of these patients, 44% had at least one failed attempt at tissue diagnosis before EUS-FNA. The sensitivity, specificity, PPV, NPV, and accuracy of EUS-FNA in solid pancreatic masses were 84.3%, 97%, 99%, 64%, and 84%, respectively. Immediate self-limited complications occurred in 10 of the 158 EUS-FNAs (6.3%). Of 90 patients contacted at 24-72 h, 78 patients (87%) responded. Of the 90 patients, 20 (22%) reported at least one symptom, all of which were minor except in three cases (one self-limited acute pancreatitis and two emergency room visits, one of which led to admission). In all, 83 patients were contacted at 30 days, and 82% responded. No additional or continued complications were reported. CONCLUSIONS: EUS-FNA is highly accurate in identifying patients with suspected pancreatic cancer, especially when other modalities have failed. Major complications after EUS-FNA are rare, and minor complications are similar to those reported for upper endoscopy. It seems that follow-up at 1 wk might capture all of the adverse events related to EUS-FNA.

Biopsy, Needle↗
PubMed2003

Results of long-term follow-up for transanal excision for rectal cancer.

Low anterior resection and abdominoperineal resection are the surgical techniques used most frequently in the treatment of rectal cancer. It is our hypothesis that selected patients with early T stage, well or moderate grade of differentiation, and small tumor size are good candidates for transanal excision in terms of minimal morbidity, low recurrence rate, and sphincter preservation. From January 1993 until August 2001 30 patients underwent transanal excision; three patients were excluded because they had histology other than adenocarcinoma. Factors analyzed included those related to the patient [age (years), gender, race, body mass index, and anal tone], tumor [size (cm), distance from the anal verge (cm), differentiation, and American Joint Committee on Cancer stage], and additional treatment. Median follow-up of the group was 40.7 months (range 0.6-99) and the primary end points were local and distant recurrence. Data are presented as mean (range). The median age of the group was 58.9 years (range 27-94); 52 per cent were female and 48 per cent were male. The mean body mass index was 25.9 (range 22.7-36.7). Preoperatively 81, 11, and 4 per cent of the patients had stage I, II, and III/IV cancer, respectively. Preoperative size of the tumor was 2.0 cm (1-3 cm), and distance from the anal verge was 5.0 cm (3-15 cm). Blood loss was 50 cm3 (5-200 cm3), and there were no operative complications. Tumor differentiation levels were well (37%) and moderate (63%). All patients had negative margins. Additional treatment consisted of radiation therapy in seven patients (six postoperative and one preoperative). Chemotherapy was given to seven patients (six postoperative and one preoperative). The local recurrence rate was 7.4 per cent (two patients), and 3.7 per cent recurred distantly (one patient). Transanal excision of low rectal cancer in selected patients is an acceptable alternative to formal resection. Important selection criteria include early T stage, well or moderate differentiation, relatively small tumor size, and negative microscopic margins. The roles of radiation and chemotherapy remain controversial.

Adenocarcinoma↗
PubMed2002

IFN-gammaupregulates apoptosis-related molecules and enhances Fas-mediated apoptosis in human cholangiocarcinoma.

Human cholangiocarcinoma is a malignancy with no effective therapy and a poor prognosis. Previously, we demonstrated that cultured human cholangiocarcinoma cell lines heterogeneously express Fas on their surface, resulting in 2 subpopulations, Fas-high and Fas-low cells. Fas-low cells are resistant to apoptosis induced by Fas antibody and the calmodulin antagonists tamoxifen and trifluoperazine and are tumorigenic in nude mice (Pan et al., Am J Pathol 1999;155:193-203). Here, we show that IFN-gamma enhances apoptosis in both Fas-high and Fas-low cells. IFN-gamma upregulates many apoptosis-related molecules, including Fas, caspase-3, caspase-4, caspase-7, caspase-8 and Bak, in both cell lines. Pretreatment with IFN-gamma facilitated Fas-mediated caspase cleavage, cytochrome c release and Bax translocation. The ability of IFN-gamma to inhibit tumorigenesis of Fas-low cells was demonstrated in nude mice. Intratumoral injection of IFN-gamma decreased tumor volumes by 78%. These findings indicate that IFN-gamma modulates the apoptotic pathway by upregulating apoptosis-related genes. This renders tumorigenic Fas-low cholangiocarcinoma cells nontumorigenic and sensitive to Fas apoptosis, thus representing a possible therapeutic modality.

Apoptosis↗
PubMed2002

Application of molecular biology studies to gene therapy treatment strategies.

The diagnosis of pancreatic cancer continues to produce fear in both patients and practitioners in large part owing to the likely incurability in all for whom the diagnosis is made. It is this reality that continually motivates the surgical and medical oncologists who endeavor to treat these patients. Currently, the cure rate for pancreatic cancer has improved only minimally, and the overall survival of patients remains dismal, with fewer than 5% of patients alive at 5 years and 92% of these patients dead at 2 years. This current treatment status has stimulated numerous studies endeavoring to understand the diverse mechanisms of cell growth in this tumor. Intensive investigative efforts have produced the understanding of new tumor suppressor genes such as DPC4 and an increasing understanding of tyrosine kinase receptors and signal transduction and their regulation of programmed cell death (apoptosis). Detection of these numerous genetic defects may give new insights and understanding of the highly chemo- and radioresistant nature of pancreatic cancer. These same findings also provide the basis for the development of new potential therapies for pancreatic cancer through gene therapy. This paper reviews the significant molecular biologic findings and their influence on the development of gene therapy strategies in the treatment of pancreatic adenocarcinoma.

Adenocarcinoma↗
PubMed2002

Quantitation of cytosine deaminase mRNA by real-time reverse transcription polymerase chain reaction: a sensitive method for assessing 5-fluorocytosine toxicity in vitro.

Cytosine deaminase/5-fluorocytosine (CD/5-FC) is a promising strategy for local cancer gene therapy. We hypothesized that CD expression within tumor cells would be directly related to efficacy and that quantitation of markers of CD expression such as mRNA, protein, and enzyme activity would therefore facilitate prediction of 5-FC toxicity. These three markers were thus quantitated by real-time quantitative reverse transcription polymerase chain reaction (Q-RT-PCR), semiquantitative immunocytochemistry (ICC), and 5-[(3)H]FC enzyme assay, respectively. Results with human colon (LS174T) cancer cells infected with a replication-incompetent adenovirus encoding CD (AdCMVCD) demonstrated a significant correlation between CD mRNA and enzyme activity up to 24 h postinfection. A direct correlation was found between CD dose (AdCMVCD PFU/cell) and CD mRNA and protein expression (P < 0.002) in both LS174T and BxPC-3 pancreatic cancer cells, but the relationship with enzyme activity was less strong in LS174T cells (P = 0.09). A remarkable concordance existed among Q-RT-PCR, ICC and enzyme assays with both cell lines. Importantly, CD dose and mRNA and protein expression inversely correlated with 5-FC IC(50) (P < 0.02). Quantitation of CD markers also facilitated identification of factors governing differential susceptibility to CD/5-FC. These results suggest that Q-RT-PCR will be useful for monitoring transgene expression in future studies using improved CD-based expression vectors and may also be useful in predicting the response to CD/5-FC therapy, which is likely to be heterogeneous in the patient population.

Antimetabolites↗
PubMed2002

Tamoxifen (TMX)/Fas induced growth inhibition of human cholangiocarcinoma (HCC) by gamma interferon (IFN-gamma).

OBJECTIVES: To evaluate the response of human cholangoicarcinoma cells to TMX treatment through the Fas pathway by pretreatment with IFN-gamma. SUMMARY BACKGROUND DATA: Cholangiocarcinoma remains one of the most difficult tumors to treat in clinical medicine. Currently, there are no effective chemotherapy treatments for this disease. Surgery offers the only opportunity for a cure, with the majority of patients failing to qualify for such treatment. This study seeks to evaluate a potential new modality for treatment of this disease. METHODS: Human cholangiocarcinoma cells were treated with anti Fas mab and sorted to two populations (Fas-positive and Fas-negative) by FAC analysis. In vitro individual cell populations were pretreated with IFN-gamma 250 units/mL x 18hs. The treated cells assayed for caspase 3, 7, 8, Bak, and for apoptosis with Annexin V after treatment with or without TMX. In Vivo 2 x 106 5 SK-ChA-1 Fas-negative cells were injected into nude mice for development of tumor xenografts. Mice received either no treatment or intra tumor IFN-gamma and/or intra peritoneal TMX. RESULTS: More than 90% (90% +/- 3.5%) of Fas-positive and 70% (71 +/- 2.3%) of Fas-negative cells underwent apoptosis after TMX treatment when pretreated with IFN-gamma. In contrast, TMX alone and IFN-gamma alone stimulated apoptosis by only 22% (22 +/- 3%) P <.00013, and 17% (17 +/- 2%) P <.0001 in Fas-ve cells respectively. In vivo human cholangiocarcinomas xenograft growth was significantly inhibited by a combination of TMX + IFN-gamma compared to controls P <.0007. CONCLUSION: TMX exposure to human cholangiocarcinoma after pretreatment with IFN-gamma allows for induction of apoptosis in vitro and significant inhibition tumor xenograft growth. The combination of these two compounds may provide novel treatment regimen for cholangiocarcinoma.

Animals↗
PubMedDate not supplied

Current status of gene therapy for pancreatic cancer.

Pancreatic adenocarcinoma remains a widespread and difficult disease to treat. Surgical resection offers the possibility of cure in a select few. However, most patients are not eligible, and conventional chemotherapy and radiation remain largely ineffective. Despite this, our understanding of the pathogenesis of the disease has advanced considerably over the past few decades. These findings provide the basis for the development of much needed new therapeutic modalities. Specifically, the application of new recombinant DNA technology and techniques to pancreatic cancer has yielded promising results. This paper reviews our current understanding of the molecular biology of pancreatic adenocarcinoma and its applications to the field of gene therapy.

Adenocarcinoma↗
PubMedDate not supplied

Regulatory cells.

Explore the source record for details and available documents.

CD4 Antigens↗
PubMedDate not supplied

Ligand activation of alternatively spliced fibroblast growth factor receptor-1 modulates pancreatic adenocarcinoma cell malignancy.

Pancreatic adenocarcinoma continues to be a devastating tumor (28,000 new cases per year in the United States; 10% 2-year survival). Pancreatic adenocarcinoma frequently (90% of the time) overexpresses fibroblast growth factor ligands (FGF-1 and FGF-2) and alternatively spliced high-affinity receptors (FGFR-1beta) (FGFR-1alpha was previously found in normal pancreatic tissue). To study the significance of this observation in vitro, PANC-1 cells were stably transfected via the pMEXneo vector containing FGFR-1alpha (PANC-1alpha) or FGFR-1beta (PANC-1beta) isoforms. Cells were treated with 1 mg/ml of 5-fluorouracil. Cells were evaluated for growth inhibition, apoptosis (propidium iodide staining and flow cytometry, caspase 3 activation) and for Bcl-x(L)/BAX expression (by Western blot analysis). In vivo, 7 x 10(6) cells of each isoform were injected into nude Balb/c mice for xenograft formation (N = 10). Compared to PANC-1beta (9%) in vitro, 5-fluorouracil-induced death was significantly (P < 0.05) increased in PANC-1alpha (20%) at 24 hours. Increased cell death in PANC-1alpha was mediated by activated caspase 3 and was correlated with decreased expression of Bcl-x(L)/BAX. In vivo, PANC-1beta readily demonstrated formation of tumor xenograft at 2 weeks, whereas PANC-1alpha did not form tumors. Alternative splicing of FGFR-1 to the beta isoform appears to correlate with pancreatic adenocarcinoma cell growth in vivo and resistance to chemotherapy. Inhibition of FGFR-1 splicing or overexpression of FGFR-1alpha inhibits pancreatic adenocarcinoma cell growth in vivo and restores cytotoxic responses to chemotherapy, thereby suggesting the basis of rational interventional strategies for this devastating tumor.

Adenocarcinoma↗
PubMedDate not supplied

Development of a therapeutic adenoviral vector for cholangiocarcinoma combining tumor-restricted gene expression and infectivity enhancement.

Cholangiocarcinoma is an invasive malignancy that is most often unresectable upon diagnosis and unresponsive to chemotherapy and radiation. While adenoviral gene therapy has shown promise in treating many tumors, systemic toxicity and low tumor transduction efficiency have hampered its application in many gastrointestinal cancers. To overcome these difficulties, we have constructed an adenoviral vector utilizing a tumor-specific promoter (TSP) for selective transgene expression and a vector with an RGD-motif in the fiber-knob region for infectivity enhancement. In seeking a TSP for cholangiocarcinoma, Secretory Leukoprotease Inhibitor, Midkine, Gastrin Releasing Peptide, VEGF, Cox-2M, and Cox-2L promoters were configures in adenoviral vectors, and evaluated in cholangiocarcinoma cells lines (Oz and SkChA-1). Luciferase assays demonstrated that Cox-2 promoters (M and L) showed the highest promoter activity, with Cox-2M appearing slightly stronger than Cox-2L. Infectivity enhanced vectors with RGD-motif in the fiber-knob region were also constructed with the luciferase transgene driven by a CMV control and the Cox-2M and Cox-2L promoters. Subsequent luciferase assays comparing the unmodified vectors to the RGD-modified versions demonstrated higher levels of luciferase activity than the RGD-infected cells. This paradigm was then applied to a therapeutic HSV-TK/GCV model by constructing RGD-enhanced HSV-TK vectors driven by Cox-2M and Cox-2L promoters. In vitro cytocidal effect analysis confirmed that the RGD-modified, cox-2 (M and L) driven vectors showed a stronger cytocidal effect upon gancyclovir administration than the vectors with wild-type fiber. The Cox-2 promoter demonstrates a favorable selectivity profile for cholangiocarcinoma, and RGD-modification further enhances transduction efficiency. This combination has potential to overcome the obstacles to clinical application of adenoviral gene therapy in cholangiocarcinoma.

Adenoviridae↗