Peptides for diagnosis and treatment of colorectal cancer.

Colorectal cancer (CRC) is a major health concern worldwide, as it is the third most frequently diagnosed cancer and the second leading cause of cancer-related death. There are a number of treatment options for CRC, however many of them are disappointing. Therefore, significant efforts are directed towards the development of new biological therapies with improved efficacy. The use of peptides in CRC treatment holds promise as emerging novel anti-cancer agents. Targeted therapy based on the use of peptides that can directly target tumor cells without affecting normal cells is evolving as an alternative strategy to conventional therapies and particularly, chemotherapy. The main advantages of peptides are their relatively easy and rapid synthesis process, and the vast possibilities for chemical modifications that can be exploited for novel peptide design and improved delivery. Peptides can be utilized directly as cytotoxic agents or indirectly as they can act as carriers of cytotoxic agents, drugs, or radioisotopes by specifically targeting tumor cells. They can also be used for diagnostic purposes. Current research focuses on developing peptides that can serve as tumor targeting moieties, permeabilize membranes to induce cytotoxicy, radiolabeled peptides, and peptide vaccines. In addition, improving targeting to tumors, reducing side effects, due to non-specific toxicity, and unraveling the pharmacokinetic characteristics of potential peptides, for either therapeutic or diagnostic use, are also subjects of intensive investigation. This review provides a brief overview on the role of peptides in CRC diagnosis and therapy that are currently being investigated, and their potential applications in the clinical setting.

Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analyses of individual participant data from randomised trials.

BACKGROUND: The vascular and gastrointestinal effects of non-steroidal anti-inflammatory drugs (NSAIDs), including selective COX-2 inhibitors (coxibs) and traditional non-steroidal anti-inflammatory drugs (tNSAIDs), are not well characterised, particularly in patients at increased risk of vascular disease. We aimed to provide such information through meta-analyses of randomised trials. METHODS: We undertook meta-analyses of 280 trials of NSAIDs versus placebo (124,513 participants, 68,342 person-years) and 474 trials of one NSAID versus another NSAID (229,296 participants, 165,456 person-years). The main outcomes were major vascular events (non-fatal myocardial infarction, non-fatal stroke, or vascular death); major coronary events (non-fatal myocardial infarction or coronary death); stroke; mortality; heart failure; and upper gastrointestinal complications (perforation, obstruction, or bleed). FINDINGS: Major vascular events were increased by about a third by a coxib (rate ratio [RR] 1·37, 95% CI 1·14-1·66; p=0·0009) or diclofenac (1·41, 1·12-1·78; p=0·0036), chiefly due to an increase in major coronary events (coxibs 1·76, 1·31-2·37; p=0·0001; diclofenac 1·70, 1·19-2·41; p=0·0032). Ibuprofen also significantly increased major coronary events (2·22, 1·10-4·48; p=0·0253), but not major vascular events (1·44, 0·89-2·33). Compared with placebo, of 1000 patients allocated to a coxib or diclofenac for a year, three more had major vascular events, one of which was fatal. Naproxen did not significantly increase major vascular events (0·93, 0·69-1·27). Vascular death was increased significantly by coxibs (1·58, 99% CI 1·00-2·49; p=0·0103) and diclofenac (1·65, 0·95-2·85, p=0·0187), non-significantly by ibuprofen (1·90, 0·56-6·41; p=0·17), but not by naproxen (1·08, 0·48-2·47, p=0·80). The proportional effects on major vascular events were independent of baseline characteristics, including vascular risk. Heart failure risk was roughly doubled by all NSAIDs. All NSAID regimens increased upper gastrointestinal complications (coxibs 1·81, 1·17-2·81, p=0·0070; diclofenac 1·89, 1·16-3·09, p=0·0106; ibuprofen 3·97, 2·22-7·10, p<0·0001; and naproxen 4·22, 2·71-6·56, p<0·0001). INTERPRETATION: The vascular risks of high-dose diclofenac, and possibly ibuprofen, are comparable to coxibs, whereas high-dose naproxen is associated with less vascular risk than other NSAIDs. Although NSAIDs increase vascular and gastrointestinal risks, the size of these risks can be predicted, which could help guide clinical decision making. FUNDING: UK Medical Research Council and British Heart Foundation.

Gene therapy of pancreatic cancer targeting the K-Ras oncogene.

Ras mutations are present in ∼95% of pancreatic cancer (PC) cases leading to increased proliferation and apoptosis resistance. The aim of this study is to selectively kill Ras-transformed cells by overexpressing the pro-apoptotic protein, p53 upregulated modulator of apoptosis (PUMA) under a Ras-responsive promoter. Colo357, Panc1 and MiaPaca, PC cell lines harboring K-Ras mutations, normal rat IEC18 enterocytes, and their K-Ras transformed R1 counterparts, were tested. We constructed adenoviral vectors containing the PUMA gene downstream to: (1) Four or five repetitive Ras-responsive elements (Ad-PY4/PY5-PUMA) and (2) a negative control (Ad-SV40-PUMA). Cell viability was estimated by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and apoptosis was evaluated by FACS. In vivo potency of the adenoviruses was evaluated in athymic nude mice. Infection with Ad-PY4/PY5-PUMA markedly inhibited cell growth (∼40-50%), and apoptosis was detected in all cells with high Ras activity, whereas IEC18 cells remained unaffected. The control vector, Ad-SV40-PUMA, did not induce any cell death. Selective and high expression of PUMA was detected in Ad-PY4-PUMA-infected cells. In vivo, Ad-PY4-PUMA inhibited by ∼35% the growth of established tumors compared with the Ad-SV40-PUMA. Selective overexpression of PUMA efficiently inhibits the growth of Ras-transformed cells while sparing the normal ones. This treatment modality may become a useful, effective and safe approach to selectively target Ras-mutated tumor cells.

The diagnosis and management of gastric cancer: expert discussion and recommendations from the 12th ESMO/World Congress on Gastrointestinal Cancer, Barcelona, 2010.

Well-recognized experts in the field of gastric cancer discussed during the 12th European Society Medical Oncology (ESMO)/World Congress Gastrointestinal Cancer (WCGIC) in Barcelona many important and controversial topics on the diagnosis and management of patients with gastric cancer. This article summarizes the recommendations and expert opinion on gastric cancer. It discusses and reflects on the regional differences in the incidence and care of gastric cancer, the definition of gastro-esophageal junction and its implication for treatment strategies and presents the latest recommendations in the staging and treatment of primary and metastatic gastric cancer. Recognition is given to the need for larger and well-designed clinical trials to answer many open questions.

Molecular markers and biological targeted therapies in metastatic colorectal cancer: expert opinion and recommendations derived from the 11th ESMO/World Congress on Gastrointestinal Cancer, Barcelona, 2009.

The article summarizes the expert discussion and recommendations on the use of molecular markers and of biological targeted therapies in metastatic colorectal cancer (mCRC), as well as a proposed treatment decision strategy for mCRC treatment. The meeting was conducted during the 11th ESMO/World Gastrointestinal Cancer Congress (WGICC) in Barcelona in June 2009. The manuscript describes the outcome of an expert discussion leading to an expert recommendation. The increasing knowledge on clinical and molecular markers and the availability of biological targeted therapies have major implications in the optimal management in mCRC.

CCL2 (pM levels) as a therapeutic agent in Inflammatory Bowel Disease models in mice.

BACKGROUND: Chemokines regulate the pathways that restrict homing of specific subsets of immune cells, and thereby fine tune the immune response at specific lymphoid and peripheral tissues. CCL2 is a chemokine that induces migration of monocytes, memory T cells, and dendritic cells. Previously, we demonstrated that pM levels of CCL2 dramatically inhibit migration of T cells. The aim was to test whether subphysiological doses of CCL2 can ameliorate murine colitis and inflammation-induced colorectal cancer. METHODS: TNBS (2,4,6 trinitrobenzene sulfonic acid) colitis and dextran sodium sulfate (DSS) colitis were induced in Balb/c and C57BL/6 mice, respectively. Mice were treated daily with intraperitoneal CCL2 injections. Disease activity was assessed clinically, histologically, and by measuring inflammatory cytokine levels. In addition, an inflammatory cancer model was induced by azoxymethane-DSS (AOM-DSS) in Balb/c mice. Mice were treated daily with CCL2 for 11 weeks and then assessed for number of tumors in the colons. RESULTS: Daily administration of CCL2 (60-120 ng) significantly decreased the development of TNBS- and DSS-induced colitis. In a DSS-AOM model, CCL2-treated mice developed significantly fewer tumors (P < 0.005) at 11 weeks. Chronic inflammation in the CCL2-treated mice was significantly less pronounced as compared to phosphate-buffered saline-treated mice. CONCLUSIONS: Administration of pM levels of CCL2 significantly inhibits migration of T cells in amelioration of TNBS and DSS colitis and inhibits development of colorectal cancer in an AOM-DSS colitis model in mice. Thus, pM levels of CCL2 may be clinically beneficial as an antiinflammatory agent in IBD.

Colonoscopic screening of an average-risk population for colorectal neoplasia.

BACKGROUND AND STUDY AIMS: The role of screening colonoscopy in an asymptomatic, average-risk population remains to be determined. Moreover, the value of screening colonoscopy in individuals older than 75 years and for right-sided lesions has recently been questioned. The aims were to assess: (i) the risk of colorectal neoplasia in a large consecutively screened asymptomatic average-risk population, aged 40-85 years; (ii) whether colonoscopy is better than sigmoidoscopy for primary screening; and (iii) the prevalence of right-sided lesions at different ages. PATIENTS AND METHODS: This prospective study, analyzed data from 1563 consecutive, asymptomatic, average-risk individuals, aged 40-85 years, who underwent screening colonoscopy. RESULTS: Overall, neoplastic lesions were detected in 262 individuals (17% of the study population), of whom 75 had advanced lesions (5% of population) and nine had colorectal cancers (CRC) (0.6% of population). The prevalence of all lesions increased with age, with the highest percentages in the > 75 age group (26.5% with neoplastic and 6 % with advanced lesions). Higher age was also associated with relatively more right-sided lesions. In particular the prevalence of proximal neoplasia, without concurrent distal neoplasia, increased from 5% in those < 50 years to 24% in those > 75 years. Those with distal lesions had a higher overall risk for proximal lesions (odds ratio [OR] 3.2); nevertheless flexible sigmoidoscopy alone would have missed up to 40% of all lesions and up to 3.5% of advanced neoplastic lesions in this patient subgroup. CONCLUSIONS: Screening colonoscopy in asymptomatic, average-risk individuals is mandatory, as noteworthy numbers of advanced colorectal neoplasias have been detected in all age groups, especially in those aged > 75. Most importantly, many of the detected lesions were proximal and would not be revealed by sigmoidoscopy alone.

The management of hepatocellular carcinoma. Current expert opinion and recommendations derived from the 10th World Congress on Gastrointestinal Cancer, Barcelona, 2008.

This article summarizes the expert discussion on the management of hepatocellular carcinoma (HCC), which took place during the 10th World Gastrointestinal Cancer Congress (WGICC) in Barcelona, June 2008. A multidisciplinary approach to a patient with HCC is essential, to guarantee optimal diagnosis and staging, planning of surgical options and selection of embolisation strategies or systemic therapies. In many patients, the underlying cirrhosis represents a challenge and determines therapeutic options. There is now robust evidence in favour of systemic therapy with sorafenib in patients with advanced HCC with preserved liver function. Those involved in the care for patients with HCC should be encouraged to participate in well-designed clinical trials, to increase evidence-based knowledge and to make further progress.

Risk of colorectal neoplasia associated with the adenomatous polyposis coli E1317Q variant.

BACKGROUND: Reports of the risk of colorectal neoplasia associated with a variant of the adenomatous polyposis coli (APC E1317Q) gene are conflicting. Using a case-control design, we investigated this relationship within a clinic-based cohort followed through the Integrated Cancer Prevention Center and the Tel-Aviv Sourasky Medical Center. MATERIALS AND METHODS: All study subjects were tested for the APC E1317Q variant at enrollment. Subjects underwent colonoscopic evaluation (+/-biopsy and/or polypectomy) and had cancer history and colorectal neoplasia risk factors assessed. The crude and adjusted risks of neoplasia associated with the E1317Q variant were calculated. RESULTS: The prevalence of the E1317Q variant was 1.4% in the entire study sample and 3.2% in Sephardic Jews. E1317Q was more prevalent among cases: 15 of 458 (3.3%) cases were carriers compared with 11 of 1431 (0.8%) controls [odds ratio (OR) 4.4, 95% CI 2.0-9.6]. When stratified by neoplasia type, adenoma risk was significantly elevated in carriers (OR 4.1, 95% CI 1.8-9.4) but colorectal cancer risk was not (OR 2.1, 95% CI 0.8-5.3). After adjustment, the E1317Q variant remained a significant predictor of colorectal adenoma (OR 4.6, 95% CI 2.0-10.8). CONCLUSIONS: The APC E1317Q variant is associated with colorectal neoplasia, particularly colorectal adenomas, but further studies are still needed. Variant prevalence is elevated in Sephardic Jews.

The diagnosis and management of rectal cancer: expert discussion and recommendations derived from the 9th World Congress on Gastrointestinal Cancer, Barcelona, 2007.

Knowledge of the biology and management of rectal cancer continues to improve. A multidisciplinary approach to a patient with rectal cancer by an experienced expert team is mandatory, to assure optimal diagnosis and staging, surgery, selection of the appropriate neo-adjuvant and adjuvant strategy and chemotherapeutic management. Moreover, optimal symptom management also requires a dedicated team of health care professionals. The introduction of total mesorectal excision has been associated with a decrease in the rate of local failure after surgery. High quality surgery and the achievement of pathological measures of quality are a prerequisite to adequate locoregional control. There are now randomized data in favour of chemoradiotherapy or short course radiotherapy in the preoperative setting. Preoperative chemoradiotherapy is more beneficial and has less toxicity for patients with resectable rectal cancer than postoperative chemoradiotherapy. Furthermore chemoradiotherapy leads also to downsizing of locally advanced rectal cancer. New strategies that decrease the likelihood of distant metastases after initial treatment need be developed with high priority. Those involved in the care for patients with rectal cancer should be encouraged to participate in well-designed clinical trials, to increase the evidence-based knowledge and to make further progress. Health care workers involved in the care of rectal cancer patients should be encouraged to adopt quality control processes leading to increased expertise.

The new scopes--broadening the colonoscopy marketplace.

Colonoscopy has been established as a screening tool for colorectal cancer and precursors in some countries. Efforts to improve instrument performance as well as patient comfort, safety and compliance have led to modifications of existing endoscopes as well as to the development of new scopes with different working mechanisms, including the colon capsule. While the former have not substantially changed performance, the true value of new scopes - partially single use and/or self propelling - can not be fully assessed, since they are either still under development and/or tested only in animals and in small groups of patients or volunteers. The colon capsule holds promise but has a too complicated preparatory regimen and too low a sensitivity at the moment. Future developments and further studies will show which of these techniques may complement or even replace traditional screening colonoscopy.

Proof-of-concept study of the Aer-O-Scope omnidirectional colonoscopic viewing system in ex vivo and in vivo porcine models.

BACKGROUND AND STUDY AIMS: The limited angle of view of standard colonoscopes means that lesions can be missed. A multidirectional viewing system (OmniVision) has been developed recently and has been incorporated into the Aer-O-Scope (GI View Ltd., Ramat Gan, Israel), a disposable, self-propelling, and self-navigating colonoscope. The objectives of this study were to qualitatively assess the sensitivity of this viewing system in an ex vivo porcine polyp induction model, and to demonstrate its feasibility and safety in live pigs. MATERIALS AND METHODS: For the ex vivo part of the study, six red metal beads of various sizes were randomly sewn into the mucosa of an unfolded, 2-meter-long porcine colonic segment. Seven passages of the Aer-O-Scope were video-recorded separately and blindly reviewed by six experienced gastroenterologists. The sensitivity of the Aer-O-Scope to detect beads of various sizes was calculated. For the in vivo experiment, in a repeated-measure study, nine female domestic pigs were examined with the Aer-O-Scope with the OmniView optics, followed immediately by examination with standard optical colonoscopy in order to assess the integrity of the colonic mucosa. RESULTS: In the ex vivo study the sensitivity of the Aer-O-Scope was 97.6% (CI 94.0%-100%) for any bead (i. e. any "polyp"). The rate of polyp detection was similar for the six endoscopists, and was consistent for all bead sizes. The average false-positive rate was 0.3% polyps per run (SD 0.61%). The mean time taken for the video assessment was 8.0 minutes (SD 4.0 minutes). In the in vivo experiments with the Aer-O-Scope, both the front-viewing and omnidirectional-viewing systems were functional in all cases. The colon in front of the optical capsule was well distended and a complete and meticulous inspection of the entire colonic mucosa was performed in all the pigs. There were no adverse events. CONCLUSIONS: The OmniVision system allows for a highly sensitive inspection of the colonic mucosa without the need for tip manipulation. Clinical studies are warranted in order to validate these results in humans.

CD24 plays an important role in the carcinogenesis process of the pancreas.

Patients with pancreatic adenocarcinoma have a doom prognosis these tumors were previously proved to express high level of CD24. The current study was aimed to demonstrate that the treatment with monoclonal antibodies to CD24 is effective, in vitro, in pancreatic cancer cells, similar to what we had previously shown in the setting of colorectal cancer. Three human pancreatic cancer cell lines, Colo357, Panc1 and MIA-PaCa, were analyzed for their expression levels of CD24 by Western blot analysis. The correlation for the protein available on the cytoplasmic membrane was assessed by ELISA assay to plates coated with fixed cells using anti-CD24 Ab as the first binder. Human cancer cell lines were tested for their response to two different anti-CD24 monoclonal antibodies and a control antibody (mouse anti-GFP). Human pancreatic adenocarcinomas cell lines that express CD24 (Colo357 and Panc1 cells) showed growth inhibition in dose and time dependent manners. These results were repetitive for the two different antibodies. Growth rate was not affected in MIA-PaCa cells that do not express CD24, or when cells were treated with a control antibody. CD24 may play an important role in the carcinogenesis process of pancreatic cancer. It may serve as a useful target in the therapy of pancreatic cancer.

The Aer-O-Scope: proof of the concept of a pneumatic, skill-independent, self-propelling, self-navigating colonoscope in a pig model.

BACKGROUND AND STUDY AIMS: Considerable training is needed to enable endoscopists to use the currently available commercial colonoscopes and sigmoidoscopes effectively and safely. The aim of this study was to evaluate the safety and efficacy of the propulsion mechanism incorporated into the Aer-O-Scope (GI View Ltd., Ramat Gan, Israel)--a novel self-propelled, self-navigating colonic endoscope for diagnostic purposes. MATERIALS AND METHODS: Twenty young female pigs underwent complete bowel preparation followed by a sedated examination using the new device. Ten pigs underwent two consecutive procedures, with a wash-out period of 7 days between each procedure. The total number of procedures was 30. Two prototypes of the Aer-O-Scope, with different cable lengths and vehicle balloon sizes (n = 20 and n = 10 for prototypes I and II, respectively) were used. Each examination was followed by a standard colonoscopy for safety evaluation. The insertion length of the Aer-O-Scope was determined by fluoroscopy images. RESULTS: The colon was adequately clean in 25 procedures. Maximum insertion was achieved in 21 procedures (84%)--80% with prototype I (n = 15) and 90% with prototype II (n = 10). The time to maximum insertion averaged 8.9 +/- 4.4 min (10 +/- 4.6 and 6.6 +/- 2.9 min for prototypes I and II; P < 0.05), and the withdrawal time averaged 3.4 +/- 2.1 and 4.2 +/- 3.4 min, respectively. The driving pressures for prototypes I and II averaged 46.3 and 34.5 mbar, respectively. The follow-up conventional colonoscopy identified no mucosal tears or perforations. Minor mucosal petechiae were noted in 43% of the cases. No adverse events were noted up to 7 days after the procedure. CONCLUSIONS: The propulsion mechanism used in this novel self-propelled, self-navigating colonoscope was effective and safe in pigs.

Sporadic adenomatous polyp regression with exisulind is effective but toxic: a randomised, double blind, placebo controlled, dose-response study.

BACKGROUND AND AIMS: A 12 month, multicentre, randomised, double blind, placebo controlled, phase 3, dose-response study was carried out. Exisulind inhibits tumour growth by induction of apoptosis. The aim of our study was to investigate if exisulind induces regression of sporadic colonic adenomas. PATIENTS AND METHODS: A 12 month multicentre randomised double blind placebo controlled phase 3 dose response study was carried out. At baseline colonoscopy, left sided polyps (3-10 mm) were tattooed, measured, and left in place. Subjects received exisulind 200 or 400 mg, or placebo daily. Follow up sigmoidoscopy was performed after six months, and removal of any remaining polyps at the 12 month colonoscopy. The primary efficacy variable was change in polyp size from baseline. RESULTS: A total of 281 patients were enrolled and randomised; 155 (55%) fulfilled the criteria for the intention to treat (ITT) analysis and 114 (41%) fulfilled the criteria for the efficacy evaluation analysis (patients who underwent the 12 month colonoscopy). The decrease in median polyp size was significantly greater (p=0.03) in patients who received exisulind 400 mg (-10 mm2) compared with those who received placebo (-4 mm2). Complete or partial response was significantly higher in the exisulind 400 mg group (54.6%) compared with the placebo group (30.2%), and disease progression was significantly lower (6.1% v 27.9%) (p=0.04 and 0.02, respectively). Increased liver enzymes (8.4%) and abdominal pain (14.7%) were also reported at a greater frequency in the exisulind 400 mg group. CONCLUSION: Exisulind caused significant regression of sporadic adenomatous polyps but was associated with more toxicity. This model of polyp regression, short in its term and involving a comparatively small patient sample size, may be the best available tool to assess a therapeutic regimen before launching into large preventive clinical studies.

Curcumin synergistically potentiates the growth-inhibitory and pro-apoptotic effects of celecoxib in osteoarthritis synovial adherent cells.

OBJECTIVES: Osteoarthritis (OA) is the Western world's leading cause of disability. Cyclo-oxygenase-2 (COX-2) inhibitors are efficient anti-inflammatory agents commonly used in the treatment of osteoarthritis. However, recent studies have shown that their long-term use may be limited due to cardiovascular toxicity. The anti-inflammatory efficacy of the phytochemical curcumin has been demonstrated in several in vitro and animal models. This study was undertaken to investigate whether curcumin augments the growth-inhibitory and pro-apoptotic effects of celecoxib in OA synovial adherent cells. METHODS: OA synovial adherent cells were prepared from human synovial tissue collected during total knee replacement surgery. The cells were exposed to different concentrations of celecoxib (0-40 mum), curcumin (0-20 mum) and their combination. Flow cytometric analysis was used to measure the percentage of cells with a subdiploid DNA content, the hallmark of apoptosis. COX-2 activity was assessed by measuring production of prostaglandin E(2) by enzyme-linked immunoassay. RESULTS: A synergistic effect was observed in inhibition of cell growth when the cells were exposed to various concentrations of celecoxib combined with curcumin. The inhibitory effect of the combination on cell growth was associated with an increased induction of apoptosis. The synergistic effect was mediated through a mechanism that involves inhibition of COX-2 activity. CONCLUSIONS: This effect may enable the use of celecoxib at lower and safer concentrations, and may pave the way for a novel combination treatment in osteoarthritis and other rheumatological disorders.

Ha-ras(val12) induces HSP70b transcription via the HSE/HSF1 system, but HSP70b expression is suppressed in Ha-ras(val12)-transformed cells.

Heat shock proteins (Hsps) are overexpressed in many tumors, but are downregulated in some tumors. To check for a direct effect of Ha-Ras(val12) on HSP70 transcription, we transiently expressed the oncoprotein in Rat1 fibroblasts and monitored its effect on HSP70b promoter-driven reporter gene. We show that expression of Ha-Ras(val12) induced this promoter. Promoter analysis via systematic deletions and point mutations revealed that Ha-Ras(val12) induces HSP70b transcription via heat shock elements (HSEs). Also, Ha-Ras(val12) induction of HSE-mediated transcription was dramatically reduced in HSF1-/- cells. Yet, residual effect of Ha-Ras(val12) that was still measured in HSF1-/- cells suggests that some of the Ha-Ras(val12) effect is Hsf1-independent. When HSF1-/- cells, stably expressing Ha-Ras(val12), were grown on soft agar only small colonies were formed suggesting a role for heat shock factor 1 (Hsf1) in Ha-Ras(val12)-mediated transformation. Although Ha-ras(Val12) seems to be an inducer of HSP70's expression, we found that in Ha-ras(Val12-)transformed fibroblasts expression of this gene is suppressed. This suppression is correlated with higher sensitivity of Ha-ras(val12)-transformed cells to heat shock. We suggest that Ha-ras(Val12) is involved in Hsf1 activation, thereby inducing the cellular protective response. Cells that repress this response are perhaps those that acquire the capability to further proliferate and become transformed clones.

Curcumin synergistically potentiates the growth inhibitory and pro-apoptotic effects of celecoxib in pancreatic adenocarcinoma cells.

BACKGROUND AND AIM: Adenocarcinoma of the Pancreas is a leading cause of cancer-related mortality, accounting for an estimated 30,000 deaths per year in the United States. Multiple studies have indicated that specific cyclooxygenase-2 (COX-2) inhibitors may serve in the prevention and treatment of a variety of malignancies including pancreatic adenocarcinoma. Recent studies had shown that the long-term use of high concentration of COX-2 inhibitors is not toxic free and may be limited due to serious gastrointestinal and cardiovascular side effects. The chemopreventive efficacy of the phytochemical, curcumin has been demonstrated in several in vitro and animal models. In this study we investigated whether curcumin potentiates the growth inhibition effect of a COX-2 inhibitor (celecoxib, Pfizer, NY, USA) in human pancreatic cancer cells. METHODS: P-34 (expressing high levels of COX-2), and MIAPaCa (expressing low levels of COX-2) and Panc-1 (no expression of COX-2) evaluated cell lines were exposed to different concentrations of celecoxib (0-40 microM), curcumin (0-20 microM) and their combination. Cell viability was by XTT assay. Apoptosis was assessed by flow cytometry and COX-2 expression was measured by Western blotting analysis. RESULTS: In P-34 cells, curcumin synergistically potentiated the inhibitory effect of celecoxib on cell growth. The growth inhibition was associated with inhibition of proliferation and induction of apoptosis. Western blot analysis showed that COX-2 expression was down-regulated by the combination therapy. CONCLUSION: Curcumin synergistically augments the growth inhibition inserted by celecoxib in pancreatic cancer cells expressing COX-2. The synergistic effect was mediated through inhibition of COX-2. This may enable the use of celecoxib at lower and safer concentrations and may pave the way for a more effective treatment in this devastating disease.