The cost of robotics: an analysis of the added costs of robotic-assisted versus laparoscopic surgery using the National Inpatient Sample.

BACKGROUND: Robotic-assisted surgery (RAS) with its advantages continues to gain popularity among surgeons. This study analyzed the increased costs of RAS in common surgical procedures using the National Inpatient Sample. METHODS: Retrospective analysis of the 2012-2014 Healthcare Cost and Utilization Project-NIS was performed for the following laparoscopic/robotic procedures: cholecystectomy, ventral hernia repair, right and left hemicolectomy, sigmoidectomy, abdominoperineal resection, and total abdominal hysterectomy (TAH). Patients with additional concurrent procedures were excluded. Costs were compared between the laparoscopic procedures and their RAS counterparts. Total costs and charges for cholecystectomy (the most common procedure in the dataset) were compared based on the payer and characteristics of hospital (region, rural/urban, bed size, and ownership). RESULTS: A total of 91,630 surgeries (87,965 laparoscopic, 3665 robotic) were analyzed. The average cost for the laparoscopic group was $10,227 ± $4986 versus $12,340 ± $5880 for the robotic cases (p < 0.001). The overall and percentage increases for laparoscopic versus robotic for each procedure were as follows: cholecystectomy $9618 versus $10,944 (14%), ventral hernia repair $10,739 versus $13,441 (25%), right colectomy $12,516 versus $15,027 (20%), left colectomy $14,157 versus $17,493 (24%), sigmoidectomy $13,504 versus $16,652 (23%), abdominoperineal resection $17,708 versus $19,605 (11%), and TAH $9368 versus $9923 (6%). Hysterectomy was the only procedure performed primarily using RAS and it was found to have the lowest increase in costs. Increased costs were associated with even higher increases in charges, especially in investor-owned private hospitals. CONCLUSION: RAS is more costly when compared to conventional laparoscopic surgery. Additional costs may be lower in centers that perform a higher volume of RAS. Further analysis of long-term outcomes (including reoperations and readmissions) is needed to better compare the life-long treatment costs for both surgical approaches.

Prediction of pancreatic anastomotic failure after pancreatoduodenectomy: the use of preoperative, quantitative computed tomography to measure remnant pancreatic volume and body composition.

OBJECTIVE: To determine whether remnant pancreatic volume (RPV), subcutaneous/visceral adipose tissue(SAT/VAT) area, and skeletal muscle (SM) area calculated from preoperative computed tomography (CT) can predict the occurrence of pancreatic anastomotic failure (PAF) after pancreatoduodenectomy (PD). BACKGROUND: Increased body mass index, small main pancreatic duct, and soft pancreatic texture are well-established predictors of PAF after PD. The impact on PAF of anthropomorphic measurements, such as RPV and body composition, is unknown. METHODS: In 173 patients undergoing PD from 2004 to 2009, cross sections of SAT/VAT/SM area were quantitated volumetrically, respectively, from preoperative CT. RPV was calculated from the CT as the sum of pancreatic tissue area to the left of the presumed pancreatic transection site. The predictive ability for multiple models using combinations of body mass index, RPV, SAT/VAT area, SM area, main pancreatic duct size, and pancreatic gland texture was described using a concordance index (c-index). RESULTS: Clinically relevant PAF occurred in 22 patients (13%). Multivariate logistic regression analysis identified RPV (P = 0.0012), VAT area (P = 0.0003), and SM area (P = 0.0006) as independent predictors of PAF. Using previously identified risk factors, the best 2-predictor model (body mass index and pancreatic duct size) resulted in a c-index of 0.748. Using anthropomorphic factors, however, the 2-predictor model using VAT and SM areas revealed a superior c-index of 0.959. CONCLUSIONS: Our 2-predictor model using VAT area and SM area based on volumetric quantification using preoperative CT may offer clinical benefit as an objective prognostic measure to predict clinically relevant PAF after PD.

Major venous resection during total laparoscopic pancreaticoduodenectomy.

BACKGROUND: The feasibility of total laparoscopic pancreaticoduodenectomy (TLPD) has been established. Laparoscopic major venous resection during TLPD has not been reported. The aim of the present study was to describe the technique and outcomes of patients undergoing TLPD with major venous resection. METHODS: Retrospective review of all consecutive patients undergoing TLPD and major venous resection from July 2007 to December 2010 was performed. Patient demographics and peri-operative outcomes were retrieved. Data are presented as mean ± standard deviation (SD) or median with range. RESULTS: Out of 129 patients undergoing TLPD, major venous resection was performed in 11 patients with a mean age of 71 years. Median operative time and blood loss was 413 (301-666) min and 500 (75-2800) ml, respectively. Venous resection included tangential (n= 10) and segmental resection (n = 1). Venous reconstruction included patch (n = 4), suture (n = 4), stapled (n = 2) and a left renal vein interposition graft (n = 1). Median mesoportal clamp time was 35 (10-82) min. There was no 30-day or in-hospital mortality. Post-operative imaging was available in 10 patients with 100% patency at the venous reconstruction site. CONCLUSIONS: Laparoscopic major venous resection during TLPD is feasible in selected patients. Extensive experience with complex laparoscopic pancreatic resection and reconstruction is advocated before attempting this procedure.

Liver-directed therapy for hepatic metastases in patients undergoing pancreaticoduodenectomy: a dual-center analysis.

OBJECTIVES: To analyze the perioperative and long-term outcomes of patients undergoing liver-directed therapy after pancreaticoduodenectomy in a large dual-center cohort of patients. BACKGROUND: Although aggressive liver-directed therapy may be beneficial, liver-directed therapy may be associated with a high risk of complications after pancreaticoduodenectomy. METHODS: Of 5025 patients who underwent pancreaticoduodenectomy at the Johns Hopkins Hospital and the Mayo Clinic between 1970 and 2008, 126 (2.5%), patients were identified who were also treated with either simultaneous or staged liver-directed therapy. Data on demographics, primary tumor, and hepatic metastasis characteristics, as well as details of the liver-directed therapy were collected and analyzed. RESULTS: Primary tumor histology included neuroendocrine carcinoma (34.9%), pancreatic ductal adenocarcinoma (33.4%), distal cholangiocarcinoma (8.7%), ampullary carcinoma (7.1%), duodenal carcinoma (4.0%), or other (11.9%). Liver-directed therapies included hepatic resection alone (45.2%), hepatic resection plus ablation (11.1%), ablation alone (7.9%), transarterial chemoembolization (9.5%), and whole-liver irradiation (22.2%). The overall morbidity following liver-directed therapy was 34.1% and overall mortality was 2.4%. Patients undergoing staged liver-directed therapy (14.5%) versus simultaneous pancreaticoduodenectomy plus liver-directed therapy (7.0%) were more likely to develop a liver abscess (P < 0.05). Of those patients who developed complications, the majority (55.8%) were major (Clavien grade >or=3). CONCLUSIONS: Pancreaticoduodenectomy plus liver-directed therapy is associated with considerable morbidity. The incidence of hepatic abscess is increased in patients undergoing staged pancreaticoduodenectomy followed by liver-directed therapy.

LY2109761, a novel transforming growth factor beta receptor type I and type II dual inhibitor, as a therapeutic approach to suppressing pancreatic cancer metastasis.

Most pancreatic cancer patients present with inoperable disease or develop metastases after surgery. Conventional therapies are usually ineffective in treating metastatic disease. It is evident that novel therapies remain to be developed. Transforming growth factor beta (TGF-beta) plays a key role in cancer metastasis, signaling through the TGF-beta type I/II receptors (TbetaRI/II). We hypothesized that targeting TbetaRI/II kinase activity with the novel inhibitor LY2109761 would suppress pancreatic cancer metastatic processes. The effect of LY2109761 has been evaluated on soft agar growth, migration, invasion using a fibroblast coculture model, and detachment-induced apoptosis (anoikis) by Annexin V flow cytometric analysis. The efficacy of LY2109761 on tumor growth, survival, and reduction of spontaneous metastasis have been evaluated in an orthotopic murine model of metastatic pancreatic cancer expressing both luciferase and green fluorescence proteins (L3.6pl/GLT). To determine whether pancreatic cancer cells or the cells in the liver microenvironment were involved in LY2109761-mediated reduction of liver metastasis, we used a model of experimental liver metastasis. LY2109761 significantly inhibited the L3.6pl/GLT soft agar growth, suppressed both basal and TGF-beta1-induced cell migration and invasion, and induced anoikis. In vivo, LY2109761, in combination with gemcitabine, significantly reduced the tumor burden, prolonged survival, and reduced spontaneous abdominal metastases. Results from the experimental liver metastasis models indicate an important role for targeting TbetaRI/II kinase activity on tumor and liver microenvironment cells in suppressing liver metastasis. Targeting TbetaRI/II kinase activity on pancreatic cancer cells or the cells of the liver microenvironment represents a novel therapeutic approach to prevent pancreatic cancer metastasis.

Predictors of mortality after elective ventral hernia repair: an analysis of national inpatient sample.

PURPOSE: Deciding between surgery and non-operative management of a non-obstructive ventral hernia (VH) in a high-risk patient often poses a clinical challenge. The aim of this study is to evaluate a national series of open and laparoscopic ventral hernia repair (VHR), and to assess predictors of mortality after elective VHR. METHODS: A retrospective analysis of 2008-2014 data from the Healthcare Cost and Utilization Project-Nationwide Inpatient Sample was performed. All patients with a primary diagnosis of abdominal wall hernia were included. Inguinal, femoral, or diaphragmatic hernias were excluded. Patients were stratified by elective versus emergent repair. Factors associated with mortality after elective VHR were analyzed. RESULTS: 103,635 patients were studied, including 14,787 (14.3%) umbilical, 63,685 (61.5%) incisional, and 25,163 (24.3%) other ventral hernias. Operative procedures included 59,993 (57.9%) elective and 43,642 (42.1%) emergent VHR. 21.3% elective VHRs were laparoscopic versus 13% in emergent cases (P < 0.001). Mesh was used in 52,642 (87.7%) elective versus 27,734 (63.5%) emergent VHR (P < 0.001). Median (interquartile range) length of stay was 2(3) days in laparoscopic and 3(3) days in open group (P < 0.001). Mortality was 0.2% (n = 135) in elective and 0.6% (n = 269) in emergent group (P < 0.001). In elective group, mortality rates were equal among laparoscopic and open VHR (0.2%), while in emergent group, it was lower in laparoscopic VHR (0.4% vs 0.6%, P = 0.028). Multivariate analysis of elective VHR showed that the following factors were associated with mortality during hospitalization: age > 50 years [Odds ratio (OR) = 1.96], male gender (OR = 2.37), congestive heart failure (OR = 2.15), pulmonary circulation disorders (OR = 5.26), coagulopathy (OR = 3.93), liver disease (OR = 1.89), fluid and electrolyte disturbances (OR = 8.66), metastatic cancer (OR = 4.66), neurological disorders (OR = 2.31), and paralysis (OR = 5.29). CONCLUSIONS: VHR has a low mortality, especially when performed laparoscopically. In patients undergoing elective VHR, higher age and some comorbidities are predictors of mortality. These include congestive heart failure, pulmonary circulation disorders, coagulopathy, liver disease, metastatic cancer, neurological disorders, and paralysis. Conservative management should be considered for these high-risk subgroups in context of the overall clinical presentation.

Outcomes of Bariatric Surgery Versus Medical Management for Type 2 Diabetes Mellitus: a Meta-Analysis of Randomized Controlled Trials.

INTRODUCTION: Bariatric surgery improves type 2 diabetes (T2D) in obese patients. The sustainability of these effects and the long-term results have been under question. OBJECTIVE: To compare bariatric surgery versus medical management (MM) for T2D based on a meta-analysis of randomized controlled trials (RCTs) with 2 years of follow-up. MATERIAL AND METHODS: Seven RCTs with at least 2-year follow-up were identified. The primary endpoint was remission of T2D (full or partial). Four hundred sixty-three patients with T2D and body mass index > 25 kg/m2 were evaluated. RESULTS: After 2 years, T2D remission was observed in 138 of 263 patients (52.5%) with bariatric surgery compared to seven of 200 patients (3.5%) with MM (risk ratio (RR) = 10, 95% CI 5.5-17.9, p < 0.001). Subgroup analysis of the Roux-en-Y gastric bypass (RYGB) showed a significant effect size at 2 years in favor of RYGB over MM for a higher decrease of HbA1C (0.9 percentage points, 95% CI 0.6-1.1, p < 0.001), decrease of fasting blood glucose (35.3 mg/dl, 95% CI 13.3-57.3, p = 0.002), increase of high-density lipoprotein (HDL) (12.2 mg/dl, 95% CI 7.6-16.8, p < 0.001), and decrease of triglycerides (32.4 mg/dl, 95% CI 4.5-60.3, p = 0.02). Four studies followed patients up to 5 years and showed 62 of 225 patients (27.5%) with remission after surgery, compared to six of 156 patients (3.8%) with MM (RR = 6, 95% CI 2.7-13, p < 0.001). CONCLUSION: This meta-analysis shows a superior and persistent effect of bariatric surgery versus MM for inducement of remission of T2D. This benefit of bariatric surgery was significant at 2 years and superior to MM even after 5 years. Compared with MM, patients with RYGB had better glycemic control and improved levels of HDL and triglycerides.

Early cardiac complications after bariatric surgery: does the type of procedure matter?

BACKGROUND: Major adverse cardiac events (MACE) can be a cause of postoperative mortality. This is specifically important in bariatric surgery due to obesity-related cardiovascular risk factors. OBJECTIVE: To assess postoperative cardiac adverse events after bariatric surgery and its independent predictors. SETTING: A retrospective analysis of 2011-2015 Healthcare Cost and Utilization Project-National Inpatient Sample. METHODS: Data on patients who underwent laparoscopic sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) were retrieved. MACE was identified as a composite variable including myocardial infarction, acute ischemic heart disease without myocardial infarction, and acute heart failure. Dysrhythmia (excluding premature beats) was identified as a separate outcome. Multivariate regression analysis for MACE was performed using demographic factors, co-morbidities, and type of surgery. RESULTS: The analysis included 108,432 patients (SG: 54.6%, RYGB: 45.4%). MACE was found in 116 patients (.1%), and dysrhythmia occurred in 3670 patients (3.4%). Median length of stay in patients with MACE was 4.5 versus 2 days in others (P < .001). There were 43 deaths overall, and 31 were in patients with MACE or dysrhythmia (P < .001). Age ≥ 50 years, male sex, congestive heart failure, chronic pulmonary disease, ischemic heart disease, history of pulmonary emboli, and fluid or electrolyte disorders were independent predictors of MACE based on multivariate analysis. Type of surgery (SG versus RYGB) was not an independent predictor for MACE (odds ratio 1.41, 95% confidence interval: .77-2.55). CONCLUSIONS: While cardiac complications are rare after bariatric surgery, their occurrence is associated with increased length of stay, hospital charges, and mortality. Older age, male sex, cardiopulmonary co-morbidities, and fluid or electrolyte disorders are predictive of MACE. RYGB does not increase the risk of MACE compared with SG.

Mortality in open abdominal aortic surgery in patients with morbid obesity.

BACKGROUND: Open abdominal aortic surgery is among procedures with high morbidity and mortality. Adverse postoperative complications may be more common in morbidly obese patients. OBJECTIVES: This study compared the outcomes of open abdominal aortic surgeries in patients with and without morbid obesity. SETTING: A retrospective analysis of 2007-2014 Healthcare Cost and Utilization Project-Nationwide Inpatient Sample. METHODS: We included patients who underwent open abdominal aortic aneurysm (AAA) repair or open aorta-iliac-femoral (AIF) bypass. Demographic factors, morbid obesity, co-morbidities, and emergent versus elective surgery were considered for univariate and multivariate analyses. RESULTS: A total of 29,340 patients (13,443 AAA repair and 15,897 AIF bypass) were included (age 66.3 ± 10.8 years, 65.7% male). The mortality was 9.1% in 536 patients with morbid obesity compared with 7.1% in patients without morbid obesity. Based on multivariate analysis, age, existing co-morbidities, emergent versus elective setting, and morbid obesity were found to be independent predictors of mortality. Patients with morbid obesity had an odds ratio of 3.61 (95% CI, 1.50-8.68; P = .004) for mortality, longer mean length of stay (11.2 versus 9.3 days, P < .001), and higher total hospital charges ($99,500 versus $73,700, P < .001). CONCLUSIONS: Morbid obesity is an independent risk factor of mortality in patients undergoing open AAA repair and AIF bypass. Weight loss strategies should be considered for morbidly obese patients with an anticipation of open abdominal aortic procedures.

NF-kappaB and AP-1 connection: mechanism of NF-kappaB-dependent regulation of AP-1 activity.

Nuclear factor kappaB (NF-kappaB) and activator protein 1 (AP-1) transcription factors regulate many important biological and pathological processes. Activation of NF-kappaB is regulated by the inducible phosphorylation of NF-kappaB inhibitor IkappaB by IkappaB kinase. In contrast, Fos, a key component of AP-1, is primarily transcriptionally regulated by serum responsive factors (SRFs) and ternary complex factors (TCFs). Despite these different regulatory mechanisms, there is an intriguing possibility that NF-kappaB and AP-1 may modulate each other, thus expanding the scope of these two rapidly inducible transcription factors. To determine whether NF-kappaB activity is involved in the regulation of fos expression in response to various stimuli, we analyzed activity of AP-1 and expression of fos, fosB, fra-1, fra-2, jun, junB, and junD, as well as AP-1 downstream target gene VEGF, using MDAPanc-28 and MDAPanc-28/IkappaBalphaM pancreatic tumor cells and wild-type, IKK1-/-, and IKK2-/- murine embryonic fibroblast cells. Our results show that elk-1, a member of TCFs, is one of the NF-kappaB downstream target genes. Inhibition of NF-kappaB activity greatly decreased expression of elk-1. Consequently, the reduced level of activated Elk-1 protein by extracellular signal-regulated kinase impeded constitutive, serum-, and superoxide-inducible c-fos expression. Thus, our study revealed a distinct and essential role of NF-kappaB in participating in the regulation of elk-1, c-fos, and VEGF expression.

Comparing Surgical Clerkship Performance of Medical and Physician Assistant Students.

OBJECTIVE: Third-year medical students (MS-III) and second-year physician assistant students (PA-S) have similar core clinical rotations during their education. Uniquely at our institution, both groups rotate together and are assessed by the same evaluation and grading standards. This study compares the performance of MS-III and PA-S during their combined surgical clerkship rotation. DESIGN: A retrospective analysis on students' final clerkship grades, individual grades for clinical performance evaluation, objective structured clinical examination, faculty tutorials, and National Board of Medical Education (NBME) general surgery examination for academic years 2013 and 2014. Statistical analysis using the Statistical Package for Social Sciences (SPSS) was used. A p < 0.05 was considered statistically significant. SETTING: The study took place in the Department of Surgery at the University of Oklahoma School of Community Medicine, Tulsa, Oklahoma. PARTICIPANTS: All MS-III and PA-S that performed a clinical rotation in the Department of Surgery at the University of Oklahoma School of Community Medicine, Tulsa were included in the study. Fourth-year medical students on elective rotations were excluded. A total of 95 students were included, 51 MS-III and 44 PA-S. RESULTS: The results indicated that MS-III had statistically significant higher clinical performance evaluation (p = 0.005), NBME (p < 0.001), and tutorial scores (p = 0.03) as compared to PA-S. However, there were no statistically significant findings between final grades and objective structured clinical examination scores. In comparing 2013 to 2014 MS-III classes, no statistically significant differences existed, but the 2014 PA-S class had statistically significant higher NBME (p = 0.022) and tutorial scores (p = 0.015) as compared to 2013 PA-S class. CONCLUSION: MS-III performed better in tests evaluating medical knowledge, possibly a reflection of more in-depth different organ systems physiology and pathophysiology education that MS-III receive. No significant difference in clerkship performance was found. This could be attributed to similar clinical education both receiving as well as PA-S often having a history of prior professional health care experience. Over time of the study, PA-S performance seems to have improved. These observations might help to improve future curricula for MS-III as well as for PA-S.

Cost of bariatric surgery and factors associated with increased cost: an analysis of national inpatient sample.

BACKGROUND: In the current healthcare environment, bariatric surgery centers need to be cost-effective while maintaining quality. OBJECTIVE: The aim of this study was to evaluate national cost of bariatric surgery to identify the factors associated with a higher cost. SETTING: A retrospective analysis of 2012-2013 Healthcare Cost and Utilization Project - Nationwide Inpatient Sample (HCUP-NIS). METHOD: We included all patients with a diagnosis of morbid obesity (ICD9 278.01) and a Diagnosis Related Group code related to procedures for obesity, who underwent Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), or adjustable gastric banding (AGB) as their primary procedure. We converted "hospital charges" to "cost," using hospital specific cost-to-charge ratio. Inflation was adjusted using the annual consumer price index. Increased cost was defined as the top 20th percentile of the expenditure and its associated factors were analyzed using the logistic regression multivariate analysis. RESULTS: A total of 45,219 patients (20,966 RYGBs, 22,380 SGs, and 1,873 AGBs) were included. The median (interquartile range) calculated costs for RYGB, SG, and AGB were $12,543 ($9,970-$15,857), $10,531 ($8,248-$13,527), and $9,219 ($7,545-$12,106), respectively (P<.001). Robotic-assisted procedures had the highest impact on the cost (odds ratio 3.6, 95% confidence interval 3.2-4). Hospital cost of RYGB and SG increased linearly with the length of hospital stay and almost doubled after 7 days. Furthermore, multivariate analysis showed that certain co-morbidities and concurrent procedures were associated with an increased cost. CONCLUSION: Factors contributing to the cost variation of bariatric procedures include co-morbidities, robotic platform, complexity of surgery, and hospital length of stay.

Overexpression of tropomysin-related kinase B in metastatic human pancreatic cancer cells.

PURPOSE: Pancreatic adenocarcinoma is currently the fourth leading cause of cancer death in the United States, and most pancreatic cancers develop locally advanced disease or metastasis at the time of diagnosis. The mechanisms by which it invades and metastasizes are not known. EXPERIMENTAL DESIGN: To identify the genes involved in pancreatic cancer metastasis, we analyzed the gene expression profiles between highly metastatic Colo357L3.6pl and parental Colo357FG pancreatic cancer cell lines using cDNA microarrays and confirmed differential gene expression by reverse transcription-PCR, Western blotting, and immunologic analysis of 54 samples from pancreatic cancer patients. The correlation with clinical outcome was also examined. The possible signaling pathways involved with tropomyosin-related kinase B (TrkB) were analyzed. RESULTS: Our findings showed that TrkB was overexpressed in the highly metastatic Colo357L3.6pl cells, which correlated with perineural invasion (P = 0.026), positive retroperitoneal margin (P = 0.0005), and shorter latency to development of liver metastasis (Cox proportional hazard ratio, 0.3; 95% confidence interval, 0.1-0.8; P = 0.01) in patient samples. Extracellular signal-regulated kinases 1 and 2 were activated and Elk-1 and AP-1 DNA binding activity was induced in Colo357L3.6pl cells. Furthermore, interleukin 8 and vascular endothelial growth factor were more strongly expressed in Colo357L3.6pl than Colo357FG cells, and these findings were confirmed in Colo357L3.6pl and Colo357FG orthotopic tumors. CONCLUSION: These results suggest that overexpression of TrkB and activation of mitogen-activated protein kinase and AP-1, which may in turn induce the expression of vascular endothelial growth factor and interleukin 8, may mediate the cardinal clinical features of locally aggressive growth and metastasis of pancreatic cancer. Our results also imply that TrkB receptor may be a novel therapeutic target for pancreatic cancer.

Inhibition of constitutive NF-kappa B activity by I kappa B alpha M suppresses tumorigenesis.

We have demonstrated that nuclear factor-kappa B (NF-kappa B) is constitutively activated in human pancreatic adenocarcinoma and human pancreatic cancer cell lines but not in normal pancreatic tissues or in immortalized, nontumorigenic pancreatic epithelial cells, suggesting that NF-kappa B plays a critical role in the development of pancreatic adenocarcinoma. To elucidate the role of constitutive NF-kappa B activity in human pancreatic cancer cells, we generated pancreatic tumor cell lines that express a phosphorylation defective I kappa B alpha (S32, 36A) (I kappa B alpha M) that blocks NF-kappa B activity. In this study, we showed that inhibiting constitutive NF-kappa B activity by expressing I kappa B alpha M suppressed the tumorigenicity of a nonmetastatic human pancreatic cancer cell line, PANC-1, in an orthotopic nude mouse model. Immunohistochemical analysis showed that PANC-1-derived tumors expressed vascular endothelial growth factor (VEGF) and induced angiogenesis. Inhibiting NF-kappa B signaling by expressing I kappa B alpha M significantly reduced expression of Bcl-x(L) and Bcl-2. The cytokine-induced expression of VEGF and Interleukin-8 in PANC-1 cells is also decreased. Taken together, these results suggest that the inhibition of NF-kappa B signaling can suppress tumorigenesis of pancreatic cancer cells and that the NF-kappa B signaling pathway is a potential target for anticancer agents.

The function of multiple IkappaB : NF-kappaB complexes in the resistance of cancer cells to Taxol-induced apoptosis.

The Rel/NF-kappaB transcription factors play a key role in the regulation of apoptosis and in tumorigenesis by controlling the expressions of specific genes. To determine the role of the constitutive activity of RelA in tumorigenesis, we generated pancreatic tumor cell lines that express a dominant negative mutant of IkappaBalpha (IkappaBalphaM). In this report, we show that the inhibition of constitutive NF-kappaB activity, either by ectopic expression of IkappaBalphaM or by treating the cells with a proteasome inhibitor PS-341 which blocks intracellular degradation of IkappaBalpha proteins, downregulates the expression of bcl-xl. We identified two putative NF-kappaB binding sites (kappaB/A and B) in the bcl-xl promoter and found that these two sites interact with different NF-kappaB proteins. p65/p50 heterodimer interacts with kappaB/A site whereas p50/p50 homodimer interacts with kappaB/B. The bcl-xl promoter reporter gene assays reveal that NF-kappaB dependent transcriptional activation is mainly mediated by kappaB/A site, indicating that bcl-xl is one of the downstream target genes regulated by RelA/p50. Both IkappaBalphaM and PS-341 completely abolish NF-kappaB DNA binding activity; however, PS-341, but not ectopic expression of IkappaBalphaM, sensitized cells to apoptosis induced by Taxol. This is due to the Taxol-mediated reactivation of RelA through phosphorylation and degradation of IkappaBbeta and the re-expression of NF-kappaB regulated bcl-xl gene in these cancer cells as ectopic expression of the bcl-xl gene confers resistance to Taxol-induced apoptosis in PS-341 sensitized cells. These results demonstrate the important function of various NF-kappaB/IkappaB complexes in regulating anti-apoptotic genes in response to apoptotic stimuli, and they raise the possibility that NF-kappaB : IkappaBalpha and NF-kappaB : IkappaBbeta complexes are regulated by different upstream activators, and that NF-kappaB plays a key role in pancreatic tumorigenesis.

Induction of apoptosis in tumor-associated endothelial cells and therapy of orthotopic human pancreatic carcinoma in nude mice.

Although gemcitabine has been accepted as the first-line chemotherapeutic reagent for advanced pancreatic cancer, improvement of response rate and survival is not sufficient and patients often develop resistance. We hypothesized that the inhibition of phosphorylation of epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR) on tumor cells and tumor-associated endothelial cells, combined with gemcitabine, would overcome the resistance to gemcitabine in orthotopic pancreatic tumor animal model. L3.6pl, human pancreatic cancer cells growing in the pancreas, and tumor-associated endothelial cells in microorgan environment highly expressed phosphorylated EGFR, VEGFR, and Akt, which regulates antiapoptotic mechanism. Oral administration of AEE788 (dual tyrosine kinase inhibitor against EGFR and VEGFR) inhibited the phosphorylation of EGFR, VEGFR, and Akt on tumor-associated endothelial cells as well as tumor cells. Although intraperitoneal (i.p.) injection of gemcitabine showed limited inhibitory effect on tumor growth, combination with AEE788 and gemcitabine produced nearly 95% inhibition of tumor growth in parallel with a high level of apoptosis on tumor cells and tumor-associated endothelial cells, and decreased microvascular density and proliferation rate. Collectively, these data indicate that dual inhibition of phosphorylation of EGFR and VEGFR, in combination with gemcitabine, produces apoptosis of tumor-associated endothelial cells and significantly suppresses human pancreatic cancer in nude mice.

Function of nuclear factor kappaB in pancreatic cancer metastasis.

PURPOSE: We seek to elucidate the role of constitutive nuclear factor kappaB (NFkappaB) activity in human pancreatic cancer cells. We have demonstrated that the transcription factor NFkappaB is activated constitutively in human pancreatic adenocarcinoma and human pancreatic cancer cell lines but not in normal pancreatic tissues or in immortalized/nontumorigenic pancreatic epithelial cells, suggesting that NFkappaB plays a critical role in development of pancreatic adenocarcinoma. EXPERIMENTAL DESIGN: By pooling all of the puromycin resistant clones after inhibitor of nuclear factor-kappaB phosphorylation mutant (IkappaBalphaM) retroviral infection, we generated pancreatic tumor cell lines that express a IkappaBalphaM (S32, 36A) that blocks NFkappaB activity. Inhibition of metastatic phenotype was assayed in an orthotopic nude mouse model. NFkappaB activity was determined by electrophoretic mobility shift assay, and the expression of NFkappaB downstream target genes was analyzed by Northern, Western, and immunohistochemical analyses. RESULTS: We showed that inhibiting constitutive NFkappaB activity by expressing IkappaBalphaM suppresses liver metastasis, but not tumorigenesis, from the metastatic human pancreatic tumor cell line AsPc-1 in an orthotopic nude mouse model. Furthermore, inhibiting NFkappaB activation by expressing IkappaBalphaM significantly reduced in vivo expression of a major proangiogenic molecule, vascular endothelial growth factor, and, hence, decreased neoplastic angiogenesis. Inhibiting NFkappaB activation by expressing IkappaBalphaM and using pharmacologic NFkappaB inhibitor PS-341 also significantly reduced cytokine-induced vascular endothelial growth factor and interleukin-8 expression in AsPc-1 pancreatic cancer cells. CONCLUSION: These results demonstrated that the inhibition of NFkappaB signaling can suppress the angiogenic potential and metastasis of pancreatic cancer, and suggest that the NFkappaB signaling pathway is a potential target for anticancer agents.

TGFbeta1 signaling via alphaVbeta6 integrin.

BACKGROUND: Transforming growth factor beta1 (TGFbeta1) is a potent inhibitor of epithelial cell growth, thus playing an important role in tissue homeostasis. Most carcinoma cells exhibit a reduced sensitivity for TGFbeta1 mediated growth inhibition, suggesting TGFbeta1 participation in the development of these cancers. The tumor suppressor gene DPC4/SMAD4, which is frequently inactivated in carcinoma cells, has been described as a key player in TGFbeta1 mediated growth inhibition. However, some carcinoma cells lacking functional SMAD4 are sensitive to TGFbeta1 induced growth inhibition, thus requiring a SMAD4 independent TGFbeta1 pathway. RESULTS: Here we report that mature TGFbeta1 is a ligand for the integrin alphaVbeta6, independent of the common integrin binding sequence motif RGD. After TGFbeta1 binds to alphaVbeta6 integrin, different signaling proteins are activated in TGFbeta1-sensitive carcinoma cells, but not in cells that are insensitive to TGFbeta1. Among others, interaction of TGFbeta1 with the alphaVbeta6 integrin resulted in an upregulation of the cell cycle inhibitors p21/WAF1 and p27 leading to growth inhibition in SMAD4 deleted as well as in SMAD4 wildtype carcinoma cells. CONCLUSIONS: Our data provide support for the existence of an alternate TGFbeta1 signaling pathway that is independent of the known SMAD pathway. This alternate pathway involves alphaVbeta6 integrin and the Ras/MAP kinase pathway and does not employ an RGD motif in TGFbeta1-sensitive tumor cells. The combined action of these two pathways seems to be necessary to elicit a complete TGFbeta1 signal.

Restoring apoptosis in pancreatic cancer cells by targeting the nuclear factor-kappaB signaling pathway with the anti-epidermal growth factor antibody IMC-C225.

We have previously demonstrated that RelA is constitutively activated in the majority of human pancreatic cancers and plays an important role in tumorigenesis and metastasis. The antiapoptotic gene bcl-xl is a downstream target of RelA, and regulation of bcl-xl transcription is mediated directly by the nuclear factor kappaB (NF-kappaB) binding sites present in the upstream promoter element of the bcl-xl gene. In this study we investigated the effects of inhibition of epidermal growth factor receptor (EGFR) signaling pathway with the anti-EGFR monoclonal antibody IMC-C225 on constitutive NF-kappaB activation and regulation of apoptosis-related genes in human pancreatic cancer cells. We found that activation of EGFR can be blocked with the anti-EGFR antibody IMC-C225 in the human pancreatic cancer cell line MDA Panc-28, leading to a marked decrease in constitutive NF-kappaB DNA binding activity. Our data also suggest that downregulation of NF-kappaB DNA binding activity by IMC-C225 leads to a decrease in bcl-xl and bfl-1 expression. Therefore, targeting the NF-kappaB signaling pathway with an anti-EGFR antibody may be one strategy to restore apoptosis in human pancreatic cancer cells, thereby enhancing the effect of chemotherapy and radiation therapy.

Fine-needle aspiration of the thyroid and correlation with histopathology in a contemporary series of 240 patients.

BACKGROUND: False-positive, false-negative, and indeterminate fine-needle aspiration (FNA) biopsy results complicate the management of patients with thyroid nodules. METHODS: Thyroid FNA results from 240 consecutive patients (seen 1991 to 2002) were categorized into four groups: positive for malignancy, negative for malignancy, indeterminate for malignancy, and nondiagnostic. Indeterminate results included follicular neoplasm, Hürthle cell neoplasm, and suspicious for papillary carcinoma. The FNA results were compared with histopathologic analysis after thyroidectomy. RESULTS: The FNA results were 76 (32%) positive for malignancy, 53 (22%) negative for malignancy, 100 (42%) indeterminate for malignancy, and 11 (5%) nondiagnostic. There were 3 (4%) false-positive and 2 (4%) false-negative FNA results. Among the 100 indeterminate FNA results, carcinoma was found in 11 (15%) of 73 follicular neoplasms, 2 (20%) of 10 Hürthle cell neoplasms, and 14 (82%) of 17 suspicious for papillary carcinoma. For the 73 patients with follicular neoplasms, nodule diameter >2 cm was associated with an increased risk of malignancy (P <0.03). CONCLUSIONS: False-negative FNA results are uncommon, supporting the practice of observation in most of these patients. Among those with indeterminate biopsy results, high-risk subgroups include patients with FNA results suspicious for papillary carcinoma and follicular neoplasms >2 cm.