Pancreatic resection combined with intraoperative radiation therapy for pancreatic cancer

EphA2‑enriched exosomes promote cell migration and are a potential diagnostic serum marker in pancreatic cancer

Pancreatic cancer (PC) is the fourth most common cause of cancer‑related mortality worldwide and is characterized by high invasiveness and early metastasis. To identify novel diagnostic markers, the present study aimed to understand the mechanism underlying PC progression. The present study demonstrated that exosomes derived from the highly metastatic Panc‑1 PC cell line were internalized by a low metastatic cell line, resulting in increased migration of the latter. Proteomics analysis further revealed that the receptor tyrosine kinase Eph receptor A2 (EphA2) was overexpressed in the Panc‑1 exosomes, and these Exo_EphA2 had the ability to transfer metastatic potential to recipient cells. Consistent with this, circulating Exo_EphA2 levels were higher in patients with PC compared with healthy controls. Taken together, these results indicated that Exo_EphA2 acts an oncogene in PC and is a potential tumor maker for PC diagnosis.

ESTRO IORT Task Force/ACROP recommendations for intraoperative radiation therapy in borderline-resected pancreatic cancer

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Radiation dose-escalation with intraoperative electron beam radiation therapy to the posterior resection margin and/or to residual disease is feasible with limited toxicity.

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Preoperative therapy prolongs the interval to surgery and IOERT, allowing an improved selection of patients who are candidates for local treatment intensification.

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Primary systemic therapy combined with chemoradiation allows to boost with IOERT in over 70% of patients with R0 surgical tumour beds.

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Median survival time ranges from 19 to 35 months in electron boosted patients.

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Overall survival at 5 years of over 30% is reported by contemporary expert IOERT institutions.

Radiation therapy (RT) is a valuable component of multimodal treatment for localized pancreatic cancer. Intraoperative radiation therapy (IORT) is a very precise RT modality to intensify the irradiation effect for cancer involving upper abdominal structures and organs, generally delivered with electrons (IOERT). Unresectable, borderline and resectable disease categories benefit from dose-escalated chemoradiation strategies in the context of active systemic therapy and potential radical surgery. Prolonged preoperative treatment may act as a filter for selecting patients with occult resistant metastatic disease. Encouraging survival rates have been documented in patients treated with preoperative chemoradiation followed by radical surgery and IOERT (>20 months median survival, >35% survival at 3 years). Intensive preoperative treatment, including induction chemotherapy followed by chemoradiation and an IOERT boost, appears to prolong long-term survival within the subset of patients who remain relapse-free for>2 years (>30 months median survival; >40% survival at 3 years). Improvement of local control through higher RT doses has an impact on the survival of patients with a lower tendency towards disease spread. IOERT is a well-accepted approach in the clinical scenario (maturity and reproducibility of results), and extremely accurate in terms of dose-deposition characteristics and normal tissue sparing. The technique can be adapted to systemic therapy and surgical progress. International guidelines (National Comprehensive Cancer Network or NCCN guidelines) currently recommend use of IOERT in cases of close surgical margins and residual disease. We hereby report the ESTRO/ACROP recommendations for performing IOERT in borderline-resectable pancreatic cancer.

Treatment of Locally Advanced Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is increasingly common and a leading cause of cancer-related mortality. Surgery remains the only possibility for cure. Upwards of 40% of patients present with locally advanced PDAC (LA-PDAC), where management strategies continue to evolve. In this review, we highlight current trends in neoadjuvant chemotherapy, surgical resection, and other multimodality approaches for patients with LA-PDAC. Despite promising early results, additional work is needed to more accurately and appropriately tailor treatment for patients with LA-PDAC.

RNAi-based therapeutic nanostrategy: IL-8 gene silencing in pancreatic cancer cells using gold nanorods delivery vehicles

RNA interference (RNAi)-based gene silencing possesses great ability for therapeutic intervention in pancreatic cancer. Among various oncogene mutations, Interleukin-8 (IL-8) gene mutations are found to be overexpressed in many pancreatic cell lines. In this work, we demonstrate IL-8 gene silencing by employing an RNAi-based gene therapy approach and this is achieved by using gold nanorods (AuNRs) for efficient delivery of IL-8 small interfering RNA (siRNA) to the pancreatic cell lines of MiaPaCa-2 and Panc-1. Upon comparing to Panc-1 cells, we found that the dominant expression of the IL-8 gene in MiaPaCa-2 cells resulted in an aggressive behavior towards the processes of cell invasion and metastasis. We have hence investigated the suitability of using AuNRs as novel non-viral nanocarriers for the efficient uptake and delivery of IL-8 siRNA in realizing gene knockdown of both MiaPaCa-2 and Panc-1 cells. Flow cytometry and fluorescence imaging techniques have been applied to confirm transfection and release of IL-8 siRNA. The ratio of AuNRs and siRNA has been optimized and transfection efficiencies as high as 88.40 ± 2.14% have been achieved. Upon successful delivery of IL-8 siRNA into cancer cells, the effects of IL-8 gene knockdown are quantified in terms of gene expression, cell invasion, cell migration and cell apoptosis assays. Statistical comparative studies for both MiaPaCa-2 and Panc-1 cells are presented in this work. IL-8 gene silencing has been demonstrated with knockdown efficiencies of 81.02 ± 10.14% and 75.73 ± 6.41% in MiaPaCa-2 and Panc-1 cells, respectively. Our results are then compared with a commercial transfection reagent, Oligofectamine, serving as positive control. The gene knockdown results illustrate the potential role of AuNRs as non-viral gene delivery vehicles for RNAi-based targeted cancer therapy applications.

Anti-cancer effect of HS-345, a new tropomyosin-related kinase A inhibitor, on human pancreatic cancer

Tropomyosin-related kinase A (TrkA) is emerging as an important player in carcinogenic progression. TrkA overexpression, which is associated with cell growth, proliferation, survival, and invasion, has been observed in pancreatic cancer. We therefore synthesized HS-345, a novel TrkA inhibitor, and evaluated its anti-cancer effect and underlying mechanism of action in pancreatic cancer. In this study, HS-345 effectively inhibited the growth and proliferation in three pancreatic cancer cell lines (PANC-1, MIA PaCa-2, and BxPC-3). Activation of the TrkA/Akt signal cascade was also inhibited by HS-345 treatment in a dose-dependent manner. The pro-apoptotic effect of HS-345 was evidenced by increased levels of cleaved caspase-3 and cleaved PARP, and decrease of Bcl/Bax expression via mitochondria membrane potential, as well as elevated numbers of TUNEL-positive apoptotic cells. HS-345 was additionally found to exert anti-angiogenic effect by decreasing the expression of HIF-1α and VEGF, major factors of angiogenesis, which were also demonstrated by the suppression of tube formation and migration of VEGF-treated human umbilical vein endothelial cells along with inhibition of blood vessel formation by HS-345 in a Matrigel plug assay with mice. Results of our investigation show that HS-345 inhibited the TrkA/Akt signaling pathway resulting in cell growth/angiogenesis inhibition and apoptosis induction. Based on our data, we suggest that HS-345 is a potential candidate for treating pancreatic cancer.

Prognostic implications of intraoperative radiotherapy for unresectable pancreatic cancer

BACKGROUND/AIMS

To assess the prognostic effect of intraoperative radiotherapy (IORT) in unresectable pancreatic cancer.

METHODS

We reviewed 198 patients with unresectable pancreatic cancer, which was found during experimental laparotomy. Liver metastasis was observed in 70 patients, peritoneal metastasis in 44, liver and peritoneal metastasis in 23 and locally advanced tumor in 61. Treatment consisted of IORT with or without postoperative chemotherapy. Overall survival (OS) and prognostic factors were evaluated for each pattern of disease spread.

RESULTS

IORT was performed in 120 patients, and chemotherapy was administered in 80. Sixty patients did not receive either treatment. OS in the untreated group was significantly inferior to that for IORT alone and IORT plus gemcitabine (GEM)-based chemotherapy. IORT and GEM-based chemotherapy were identified as independent prognostic factors [hazard ratio (HR) = 0.51, p < 0.001; HR = 0.43, p < 0.001]. IORT was an independent prognostic determinant for patients with peritoneal metastasis (HR = 0.24, p = 0.011) but not for those with liver metastasis (HR = 0.78, p = 0.381).

CONCLUSION

IORT followed by GEM-based chemotherapy is the recommended treatment strategy in unresectable pancreatic cancer. and IAP.

Phenotype and genotype of pancreatic cancer cell lines

The dismal prognosis of pancreatic adenocarcinoma is due in part to a lack of molecular information regarding disease development. Established cell lines remain a useful tool for investigating these molecular events. Here we present a review of available information on commonly used pancreatic adenocarcinoma cell lines as a resource to help investigators select the cell lines most appropriate for their particular research needs. Information on clinical history; in vitro and in vivo growth characteristics; phenotypic characteristics, such as adhesion, invasion, migration, and tumorigenesis; and genotypic status of commonly altered genes (KRAS, p53, p16, and SMAD4) was evaluated. Identification of both consensus and discrepant information in the literature suggests careful evaluation before selection of cell lines and attention be given to cell line authentication.

Advances in the treatment of pancreatic cancer: limitations of surgery and evaluation of new therapeutic strategies

Pancreatic ductal carcinoma is one of the most dismal malignancies of the gastrointestinal system. Even after curative resection, the actual 5-year survival is only 10%-20%. Of all the treatments used against pancreatic cancer, surgery is still the only one that can achieve complete cure. Pancreatic cancer spreads easily to the adjacent tissues and distant metastasis is common. Typically, this cancer invades the retropancreatic neural tissue, duodenum, portal vein (PV), and superior mesenteric vein (SMV), or regional lymph nodes. For this reason, aggressive surgery that removes the cancerous lesion completely is recommended. Several retrospective and prospective studies have been conducted to validate the usefulness of aggressive surgery for pancreatic cancer in the past few decades. Surprisingly, the survival benefits of aggressive surgery have been denied by most randomized controlled trials (RCTs). This implies that surgery alone is not enough. Thus, adjuvant therapy, such as radiotherapy and chemotherapy, has been given in combination with surgery to improve survival. Although the benefits of radiotherapy alone are limited, the results of chemotherapy are promising. Other newly evolving molecular targeting drugs may also improve the treatment outcomes of pancreatic cancer.

Adjuvant therapy for pancreatic cancer: a review

Pancreatic cancer is uniformly fatal unless it can be surgically resected. Survival rates for the 15% to 20% of patients who have resectable disease, however, are a disappointing 10% to 30%, depending on the status of margins and surrounding lymph nodes. In the mid-1980s, a landmark study by the Gastrointestinal Tumor Study Group was the first to demonstrate a survival benefit from adjuvant therapy in the form of chemoradiation. Since then, several studies in both North America and Europe have tested the role of adjuvant chemotherapy or chemoradiation in pancreatic cancer, and the results have stirred great controversy. For this review, the evidence for adjuvant therapy in pancreatic cancer was examined, and the significant practice differences that exist between North American and European oncologists were highlighted. The authors investigated the results from the European Study Group for Pancreatic Cancer-1 trial and the reasons why that study has served to reinforce rather than resolve these trans-Atlantic differences. They also reviewed preliminary data from more recent adjuvant trials and explored the possible benefits of a neoadjuvant approach.

Tumor size significantly correlates with postoperative liver metastases and COX-2 expression in patients with resectable pancreatic cancer

BACKGROUND/AIM

Local treatment often fails in patients with resectable pancreatic cancer due to the postoperative development of distant metastases, especially liver metastases. We determined the prognostic factors for postoperative liver metastases in pancreatic cancer patients following surgical resection with combined radiotherapy.

METHODS

Sixty-four patients with nonmetastatic, resectable pancreatic cancer were entered into this study. All of these patients had pancreatic resection surgery combined with radiotherapy. The development of postoperative liver metastases was carefully followed, and the survival ratio was evaluated using the Kaplan-Meier method. The prognostic importance of clinicopathological factors and molecular characteristics was analyzed by the Cox proportional hazards model. The correlation study was performed using Fisher's exact test.

RESULTS

Tumor size, curability, and histological type of differentiation were statistically significant independent prognostic factors. On multivariate analysis, curability and histological type of differentiation were statistically significant. Only tumor size (> or = 3 cm) was significantly correlated with postoperative liver metastases, as well as cyclooxygenase-2 expression.

CONCLUSIONS

There were three significant prognostic factors in patients with resectable pancreatic cancer who had local therapy. Patients who have a large tumor require particularly careful follow-up for postoperative liver metastases.

Late complication in patients undergoing pancreatic resection with intraoperative radiation therapy: gastrointestinal bleeding with occlusion of the portal system

BACKGROUND

There are few reports of late complications in patients who have undergone pancreatic resection with intraoperative radiation therapy (IORT), because carcinoma of the pancreas (PCa) and the bile duct (BCa) have a poor prognosis. The purpose of the present paper was to review gastrointestinal (GI) bleeding occurring with occlusion of the portal system (PVs) as a complication of IORT in patients surviving long term without recurrence.

PATIENTS

From 1990 to 1999, 45 patients underwent surgical resection of the pancreas with IORT. Eleven of these patients survived >3 years without recurrence, and occlusion of PVs was recognized in five patients at follow-up examination. Three of these five patients received repeated blood transfusions for GI bleeding.

RESULTS

One patient had BCa and two had PCa, and pancreatoduodenectomy was carried out. The delivered radiation doses of IORT were 30 Gy (two patients) and 35 Gy (one patient). The postoperative periods to initial GI bleeding were 36, 26 and 9 months, respectively. In all cases, angiography revealed occlusion of PVs and the collateral circulation. The bleeding points were esophageal varix (case 1), remnant stomach varix (case 2) and a jejunal ulcer (case 3), and blood transfusions were carried out totaling 44, 60 and 16 units, respectively. The GI bleeding disappeared spontaneously in case 1, developed sporadically in case 2 and was stopped by metallic stent insertion in PVs in case 3.

CONCLUSION

During long-term follow up after pancreatectomy with IORT, it is necessary to monitor patients for GI bleeding. A clinical trial on optimum doses, long-term safety and benefit of IORT is necessary.

Final results of a prospective trial of a PEFG (Cisplatin, Epirubicin, 5-Fluorouracil, Gemcitabine) regimen followed by radiotherapy after curative surgery for pancreatic adenocarcinoma

BACKGROUND

Postoperative management of patients with pancreatic adenocarcinoma (PA) is controversial.

METHODS

The aim of this pilot study was to assess the feasibility of postoperative combination chemotherapy followed by radiotherapy in patients aged 18-70 years with a histological diagnosis of PA, and Karnofsky performance status (KPS) > or =70. Cisplatin and epirubicin 40 mg/m2 on day 1, gemcitabine 600 mg/m2 on day 1 and 8, and 5-fluorouracil 200 mg/m2/day as protracted infusion (PEFG regimen) were delivered every 28 days for 4 cycles. Assuming a minimum one-year disease-free survival (DFS) of interest of 65% and a maximum of low interest of 45% (alpha 0.05; beta 0.10), the target enrollment was 51 patients, and the strategy would be considered to deserve further analysis if more than 29 patients were DF at one-year from surgery.

RESULTS

Fifty-one patients, KPS >80: 29, median tumor size 3.5 cm, stage II/III/IVA: 2/34/13, grade 3-4: 22, positive resection margins: 26, node positive: 46, received 179 cycles of chemotherapy. Main grade 3/4 toxicity consisted of neutropenia (51%), thrombocytopenia (18%), and anemia (4%). One-year DFS was 67 +/- 7%. Two-year overall survival was 53 +/- 7%.

CONCLUSION

Postoperative management of PA with this multimodality strategy was well tolerated and yielded a promising outcome.

Inhibition of SRC tyrosine kinase impairs inherent and acquired gemcitabine resistance in human pancreatic adenocarcinoma cells

PURPOSE

We tested the hypotheses that Src tyrosine kinase overactivity represents a chemoresistance mechanism and that Src inhibition may enhance gemcitabine cytotoxicity in pancreatic adenocarcinoma cells.

EXPERIMENTAL DESIGN

Pancreatic adenocarcinoma cells PANC1, MiaPaCa2, Capan2, BxPC3, and PANC1(GemRes), a stably gemcitabine-resistant subline of PANC1, were exposed to combinations of gemcitabine and Src tyrosine kinase inhibitor 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2). Src expression, phosphorylation (Tyr-416), and activity were analyzed by immunoblotting and in vitro kinase assay. Expression of the M2 subunit of ribonucleotide reductase (RRM2), a putative chemoresistance enzyme, was quantified by Northern and Western blot. Cellular proliferation was quantified by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Apoptosis was characterized by YO-PRO-1/propidium iodide staining, fluorometric caspase profiling, and caspase inhibition (Z-Val-Ala-Asp-fluoromethyl ketone). The effects of constitutively active and dominant negative Src were determined. The therapeutic efficacy of PP2 in combination with gemcitabine was tested in nude mice orthotopically xenografted with PANC1(GemRes).

RESULTS

Greater gemcitabine resistance was associated with higher Src phosphorylation and activity, both of which were higher in PANC1(GemRes), relative to PANC1; total Src levels were alike. PANC1(GemRes) overexpressed RRM2. PP2 enhanced inherent gemcitabine chemosensitivity and attenuated gemcitabine resistance in PANC1(GemRes). Constitutively active Src increased gemcitabine chemoresistance; dominant negative Src impaired gemcitabine chemoresistance. PP2 augmented gemcitabine-induced caspase-mediated apoptosis, suppressed RRM2 expression, and decreased activity of the RRM2-regulating transcription factor E2F1 in PANC1(GemRes). PP2 and gemcitabine in combination substantially decreased tumor growth and inhibited metastasis in vivo.

CONCLUSIONS

Increased Src tyrosine kinase activity represents a potential chemoresistance mechanism and a promising therapeutic target warranting further investigation in gemcitabine-resistant pancreatic adenocarcinoma.

Conclusions from the European Study Group for Pancreatic Cancer adjuvant trial of chemoradiotherapy and chemotherapy for pancreatic cancer

Pancreatic ductal adenocarcinoma remains one of the most difficult cancers to treat. It is a tumor that tends to present late, and surgical resection is only possible in a minority of patients. After successful surgery, the prognosis is still relatively poor. Attempts at more radical pancreatic resections and extended lymphadenectomy, although feasible without excessive morbidity and mortality, have failed to produce any convincing improvement in survival. During the last few years, therefore, efforts have been directed toward the development of adjuvant therapies in an attempt to improve outcome. This article describes the main trials of adjuvant chemotherapy, chemoradiotherapy, and chemoradiotherapy with follow-on chemotherapy and presents the results of the European Study Group for Pancreatic Cancer (ESPAC) 1 trial and the status of the ESPAC 2 and 3 trials.

Adjuvant therapy for pancreatic cancer: an evolving paradigm

Pancreatic cancer is the fourth leading cause of death in men and fifth in women in the United States. The median survival is 8 to 12 months for patients with locally advanced and unresectable disease and only 3 to 6 months for those with metastatic disease at presentation. Surgical resection offers the only potentially curative treatment. However, only 15% to 20% of patients present with tumors amenable to resection at initial diagnosis. Even for those who undergo resection, the prognosis remains poor. The 5-year survival following pancreaticoduodenectomy is only about 25% to 30% for node-negative tumors and 10% for node-positive tumors. Because of the dismal outcome for patients with resectable pancreatic cancer, adjuvant therapy has been administered in an attempt to improve the local control and overall survival. This review highlights historic and current perspectives of adjuvant therapy in resected pancreatic cancer.

The evolving role of postoperative adjuvant radiation therapy for pancreatic cancer

The benefit of postoperative adjuvant chemoradiation in the treatment of resected pancreatic cancers was first established by a randomized trial conducted by the Gastrointestinal Tumor Study Group in 1974. During the past 3 decades, treatment has evolved toward more dose-intensive regimens of chemoradiation. Historical split-course conventional radiation therapy has been replaced by continuous-course radiotherapy to higher doses, and gemcitabine is being actively investigated as a potentially more effective agent than 5-fluorouracil. This article critically examines the results of important randomized multi-institutional trials and reviews the evolution toward dose-intensive adjuvant treatment regimens. Implications of the recently completed intergroup study are discussed, modern radiation therapy delivery techniques are reviewed, and suggestions for future trials are made.

A study of radiotherapy modalities combined with continuous 5-FU infusion for locally advanced gastrointestinal malignancies

AIM

We describe the feasibility of combining infusional 5-fluorouracil (5-FU) with intraoperative radiation therapy (IORT).

METHODS

Patients with surgically resectable locally advanced gastrointestinal cancers were treated concurrently during surgery with IORT and a 72 h infusion of 5-FU. Patients without previous external beam radiation therapy (EBRT) were subsequently treated with EBRT (40-50Gy) concurrent with a 21-day continuous infusion of 5-FU. Pancreatic, gastric, duodenal, ampullary, recurrent colorectal, and recurrent anal cancer were included.

RESULTS

During IORT/5-FU, no chemotherapy-related grade III or IV hematologic or gastrointestinal toxicity was noted. Post-surgical recovery or wound healing was not affected. One of nine patients who received post-operative radiation required a treatment break. During follow-up, there were more complications in patients with pelvic tumours, especially those with previous radiation. Nine patients have had local and/or local regional recurrences, two of these in the IORT field.

CONCLUSIONS

Treatment with a combination of IORT and 5-FU followed by EBRT and 5-FU is feasible. However, long-term complications may be increased in previously irradiated recurrent pelvic tumours.

Intraoperative radiation therapy for pancreatic adenocarcinoma: the Komagome hospital experience

We analyzed 144 patients with pancreatic adenocarcinoma who had received intraoperative radiation therapy (IORT) in combination with external beam radiation therapy (EBRT) within the past 20 years. The patients were divided into 2 groups: group 1 contained 65 patients with locally unresectable tumors who underwent bypass operations and group 2 contained 68 patients with resectable tumors who underwent pancreatic resection. As a pilot study, we performed additional arterial infusion chemotherapy after changing peripancreatic hemodynamics during EBRT in the remaining 11 patients. The 30 patients who received R0 resection had the best survival rates (3-year survival rate of 35.4%), while 3 patients with stage III disease survived more than 5 years. The survival of group 1 patients nearly equaled that of group 2 patients who underwent R1 or R2 resection (median survival, 10.9 vs. 11.1 months, respectively; P = 0.43). The 1-year survival rate for the 11 patients receiving arterial infusion chemotherapy was 45.4%, and 5 patients survived over 1 year without developing hepatic metastasis or regrowth of primary tumors. The survival benefits obtained using this form of radiotherapy are apparently limited. On the other hand, additional arterial infusion chemotherapy employing a new drug delivery system using hemodynamic change does appear promising.

The role of intraoperative radiotherapy in pancreatic cancer

In single-institution studies, IORT at appropriate doses seems to safely improve local control in patients who have locally advanced pancreatic cancer, compared with historical controls. IORT also has been a component of adjuvant treatment programs that have led to excellent local control in resected patients. When considering the use of IORT, it is essential to have an understanding of the physical characteristics of the electron beam and how it can differ with the use of flat and beveled applicators. Although apparent improvement in local control with the use of IORT seems to have produced some improvement in median survival rates, high rates of distant failure continues to prevent a significant improvement in long-term survival. Because effective local control in patients with unresectable pancreatic cancer is a prerequisite to the development of curative therapies, the development of improved systemic therapies in patients with locally advanced pancreatic cancer will likely make local therapies such as the use of IORT even more important in the future.

EphA2: a determinant of malignant cellular behavior and a potential therapeutic target in pancreatic adenocarcinoma

The EphA2 receptor tyrosine kinase is overexpressed in a variety of human cancers. We sought to characterize the role of EphA2 in pancreatic adenocarcinoma and, using RNA interference (RNAi) mediated by small interfering RNA (siRNA), we determined the effects of suppressing EphA2 expression in vitro and in vivo. EphA2 expression in PANC1, MIAPaCa2, BxPC3 and Capan2 cells was assessed by Northern and Western blot. We artificially overexpressed EphA2 by transient transfection and suppressed EphA2 expression using RNAi. Cellular invasiveness was quantified by modified Boyden chamber assay. Anoikis was induced by anchorage-independent polyHEMA culture and caspase 3 activity was quantified fluorometrically. Focal adhesion kinase (FAK) phosphorylation was assessed by immunoprecipitation. EphA2 siRNA treatment was assessed in a nude mouse xenograft model. Pancreatic adenocarcinoma cells differentially express EphA2. Inherent and induced EphA2 overexpression is associated with increased cellular invasiveness and anoikis resistance. EphA2 siRNA suppresses EphA2 expression, cellular invasiveness, anoikis resistance and FAK phosphorylation in vitro and retards tumor growth and inhibits metastasis in vivo. EphA2 is both a determinant of malignant cellular behavior and a potential therapeutic target in pancreatic adenocarcinoma.

CEACAM6 gene silencing impairs anoikis resistance and in vivo metastatic ability of pancreatic adenocarcinoma cells

Anoikis is the apoptotic response induced in normal cells by inadequate or inappropriate adhesion to substrate. It is postulated that resistance to anoikis facilitates tumorigenesis and metastasis. Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) is an immunoglobulin superfamily member overexpressed in a number of human cancers and implicated in anoikis resistance. We tested the effect of CEACAM6 gene silencing on anoikis in pancreatic adenocarcinoma cell lines. Anoikis was induced in PANC1, Capan2, MiaPaCa2 and Mia(AR) (a MiaPaCa2-derived anoikis-resistant subline) by culture in poly-2-hydroxyethylmethacrylate-coated wells. Anoikis was quantified by YO-PRO-1/propidium iodide staining and flow cytometry. The role of caspase activation was determined using fluorometric profiling and the caspase inhibitor Z-Val-Ala-Asp-fluoromethyl ketone (Z-VAD-fmk). CEACAM6 expression was suppressed by RNA interference. Using a nude mouse orthotopic xenograft model, we assessed the effect of this treatment on in vivo metastatic ability. Anoikis resistance was associated with increased CEACAM6 expression. CEACAM6-specific short interfering ribonucleic acid (siRNA), but not control siRNA, increased susceptibility to caspase-mediated anoikis, an effect abrogated by Z-VAD-fmk, and decreased Akt phosphorylation (Ser-473) under anchorage-independent conditions. CEACAM6 gene silencing reversed the acquired anoikis resistance of Mia(AR) and inhibited its in vivo metastatic ability. CEACAM6 warrants further investigation as a novel therapeutic target for the treatment of pancreatic adenocarcinoma.

Treatment of pancreatic cancer: challenge of the facts

Adenocarcinoma of the pancreas is associated with the worst survival of any form of gastrointestinal malignancy. In spite of the progress in surgical treatment, resulting in increasing resection rates and a decrease in treatment-related morbidity and mortality, the true figures of cure are even today below 3%. The dissemination of pancreatic cancer behind the local tissue compartments restricts the short-term (< 3 years) and long-term outcome for patients who have undergone resection. By histological evaluation, less than 15% of the patients undergoing R(0) resection have a pN(0) status, more than 60% suffer from lymph angiosis carcinomatosa, and more than 50% suffer extrapancreatic nerve plexus infiltration. Hematoxylin and eosin-negative lymph nodes were found to be cancer positive when reverse transcriptase polymerase chain reaction (RT- PCR) or immunostaining was applied to the HE-negative lymph nodes. Cancer of the uncinate process has a very poor prognosis because there are no early symptoms; vessel wall involvement occurs early and frequently; a high association of liver metastasis exists as well. Surgery offers a low success rate, but it provides the only chance of cure. Ductal pancreatic cancer is diagnosed in more than 95% of the cases in an advanced stage; potentially curative resection can be performed only in about 10%-15% of these patients. Major contributions of surgery to improved treatment results are the reduction of surgical morbidity--e.g., early postoperative local and systemic complications--and a decrease of hospital mortality below 3%-5%. In most recently published prospective trials, R(0) resection has been reported to result in an increase in short-term survival beyond that recorded for patients with residual tumor. However, R(0) resection fails to improve long-term survival. In many published R(0) series, standard tissue resection of pancreatic head cancer with the Kausch-Whipple procedure failed to include remote cancer cell-positive tissues in the operative specimen; e.g., N(2)-lymph nodes, nerve plexus, and perivascular extrapancreatic and retropancreatic tissues were not excised. Cancer recurrence after so-called R(0) resection with curative intent is frequently the consequence of cancer left behind. Thus, long-term survival (> 5 years) is observed in a very small group of patients, contradicting the published 5-year actuarial survival rates of 20%-45% for resected patients. The assessment of clinical benefit from surgical or medical cancer treatment should therefore be based on several end points, not only on actuarial survival. Publication of actuarial survival figures must include the number of observed (actual) survivals, the definition of the subset of patients followed after resection, and the total number of patients in the study group; anything less is misleading. In reporting pancreatic cancer treatment trial results after oncological resections, more convincing primary end points to evaluate treatment efficacy are median survival (in months), actual survival at 1-5 years, and progression-free survival (in months). In series with multimodality treatment, clinical benefit response as well as quality of life measurements using the EORTC Quality of Life index C30 (QLQ-C30) are of importance in evaluating survival data. Adjuvant treatment improves survival after oncological resection; however, the short-term and long-term benefit after adjuvant chemotherapy in R(0) as well as in R(1)-(2) resected patients has not yet been underscored by data from controlled clinical trials. The survival benefit (median survival time) of adjuvant chemotherapy or radiochemotherapy has been demonstrated to be 6-10 months. Therefore, after oncological resection of pancreatic cancer each patient should be offered adjuvant treatment. A neoadjuvant treatment protocol for pancreatic cancer, however, has not been established.

Inhibition of tyrosine kinase Src suppresses pancreatic cancer invasiveness

BACKGROUND

Src is a 60-kDa tyrosine kinase that plays a critical role in signal transduction associated with cell-extracellular matrix interactions. We tested the hypothesis that Src inhibition might suppress pancreatic cancer cellular invasiveness.

METHODS

We tested the effects of pyrazolopyrimidine (a Src kinase-specific inhibitor) on 3 human pancreatic cancer cell lines: BXPC-3, MIAPaCa-2, and PANC-1. Src expression was assayed with Western blotting. Pyrazolopyrimidine-mediated inhibition of Src phosphorylation was confirmed by immunoprecipitation. Matrix metalloproteinase (MMP) activities and cellular invasive potential were assessed by use of zymography and Boyden chamber assays, respectively. Cell growth was assessed with the MTT assay.

RESULTS

Src was expressed in all 3 pancreatic cancer cell lines tested. Pyrazolopyrimidine completely suppressed Src phosphorylation, inhibited MMP2 (72kDa) and MMP9 (92kDa) activities by 40% to 34% (P <.05), and suppressed cellular invasiveness by more than 90% (P <.05) in all 3 cell lines. Pyrazolopyrimidine had variable effects on cell growth: 50% reduction (P <.05) in BXPC-3, 7% reduction (P >.05) in MIAPaCa-2, and 22% reduction (P <.05) in PANC-1.

CONCLUSIONS

Inhibition of Src signaling results in a marked reduction of pancreatic cancer cellular invasiveness. Src may represent a novel therapeutic target for this deadly cancer.

Adjuvant therapy in pancreatic cancer: historical and current perspectives

The results from pancreatic ductal adenocarcinoma appear to be improving with increased resection rates and reduced postoperative mortality reported by specialist pancreatic cancer teams. Developments with medical oncological treatments have been difficult, however, due to the fundamentally aggressive biological nature of pancreatic cancer and its resistance to chemotherapy coupled with a relative dearth of randomised controlled trials. The European Study Group for Pancreatic Cancer (ESPAC)-1 trial recruited nearly 600 patients and is the largest trial in pancreatic cancer. The results demonstrated that the current best adjuvant treatment is chemotherapy using bolus 5-fluorouracil with folinic acid. The median survival of patients randomly assigned to chemoradiotherapy was 15.5 months and is comparable with many other studies, but the median survival in the chemotherapy arm was 19.7 months and is as good or superior to multimodality treatments including intra-operative radiotherapy, adjuvant chemoradiotherapy and neo-adjuvant therapies. The use of adjuvant 5-fluorouracil with folinic acid may be supplanted by gemcitabine but requires confirmation by ongoing clinical trials, notably ESPAC-3, which plans to recruit 990 patients from Europe, Canada and Australasia. Major trials such as ESPAC-1 and ESPAC-3 have set new standards for the development of adjuvant treatment and it is now clear that such treatment in this field has the potential to significantly improve both patient survival and quality of life after curative resection.

Different radiogenic effects on microcirculation in healthy pancreas and in pancreatic carcinoma of the rat

OBJECTIVE

To compare the radiogenic effects on microcirculation in healthy and malignant pancreatic tissue.

SUMMARY BACKGROUND DATA

Vascular injury is an important effect of radiotherapy, which has been suggested for antiangiogenic tumor therapy.

METHODS

An established model of duct-like pancreatic cancer (DSL6A) was used. Investigation was performed in 12 healthy and 24 tumor-bearing Lewis rats. The tumors were locally irradiated with 15 Gy in 12 animals 4 weeks after intraperitoneal inoculation. Additionally, local radiation of the normal pancreas was performed in six healthy animals. Intravital microscopy of tumor and normal pancreatic microcirculation was performed 5 days after radiation. Relevant parameters were erythrocyte velocity and functional vessel density. Tumor apoptosis and the fraction of vital tumor cells were estimated histologically 5 and 12 days after radiation.

RESULTS

Local radiation with 15 Gy caused a pronounced impairment of blood flow and functional capillary density in the normal pancreas 5 days after radiation, while the tumor blood flow was not significantly changed. A significant reduction in the fraction of vital tumor cells and a significant increase in tumor apoptosis were observed 12 days after radiation.

CONCLUSIONS

Local radiation impairs blood flow in healthy pancreas but not in pancreatic cancer tissue. Tumor cell death is the leading consequence of radiation injury in malignant pancreatic tissue without affecting the vascular system of the tumor. The authors conclude that external beam radiation does not appear to be a useful adjunct for a vascular-targeted therapy in pancreatic carcinoma but causes distinct hypoperfusion in the healthy pancreas.

Impact of intraoperative radiation on postoperative and disease-specific outcome after pancreatoduodenectomy for adenocarcinoma: a propensity score analysis

For periampullary cancer,intraoperative radiation therapy (IORT) administered to the site with the highest locoregional recurrence risk carries the rationale to improve tumor control. An IORT effect on survival remains unclear. IORT impact on postoperative outcomes after pancreatectomy for adenocarcinoma was analyzed, with a specific attempt to correct for the nonrandom IORT treatment assignment, and to account for treatment group imbalances in the interpretation of outcome differences. A propensity-score-adjusted analysis, based on variable selection by logistic regression, was used to rebalance treatments. Between 1989 and 1999, 61 patients underwent partial or total pancreatectomy for a primary periampullary adenocarcinoma at the City of Hope National Medical Center. Diagnoses included pancreatic (n = 36), duodenal (n = 11), ampullary (n = 10), and bile duct cancer (n = 4). Thirty patients received IORT to the resection area, with a median dose of 15 Gy (range: 10-20), followed by postoperative external beam radiation (n = 24). Mortality was 0%, the complication rate 61%. Of 33 patients with a documented recurrence, 6 had an isolated locoregional recurrence only (1 IORT versus 5 no IORT, = 0.05); the systemic recurrence pattern differed as well (IORT 94%, no IORT 67%; = 0.04). IORT had no significant impact on hospital stay (overall median: 17 days), disease-free survival (16 months), and overall survival (23 months) when adjusted for those most relevant variables reflecting IORT treatment group assignment propensity. After adjustment for relevant propensity factors, IORT was not linked to a significantly increased risk for complications, hospital stay, or survival hazard. The recurrence pattern may be affected in some patients, but systemic recurrences predominate. We continue to explore IORT in combination with systemic chemotherapy.

Adjuvant radiotherapy in resectable pancreatic carcinoma

AIM

Pancreatic cancer is a near fatal disease. External beam radiotherapy and intraoperative radiation therapy (IORT) has been proposed with the aim to improve clinical outcome in resectable tumors. The aim of this study is to assess the feasibility and outcome in patients with cT1-3 pancreatic cancer, treated with surgery, external beam radiotherapy and IORT.

METHODS

From 1990 to 1996, 17 patients with clinical stage T1-3N0-1M0 adenocarcinoma of the head of the pancreas were treated with pancreatectomy and pre- (nine patients: 5 Gy), intra- (all patients: 10 Gy) and post-operative (all patients: 50 Gy) radiotherapy. The pathologic T stages were: 4 pT2 and 13 pT3. The pathologic N stages were: 9 pN0 and 8 pN1. Minimum follow-up in living patients was 60 months.

RESULTS

No perioperative mortalities were recorded. Two patients showed postoperative morbidity (11.8%) which required a subsequent laparotomy. The disease-free survival at 1, 3 and 5 years was 41, 23 and 18%, respectively (median: 9 months). The overall survival at 1, 3 and 5 years was 70%, 41% and 18%, respectively (median: 17.5 months). Three patients developed local failure (17.6%) and 12 patients showed distant metastases (70.6%). Univariate analysis (logrank) showed: a significant correlation between both N-stage and retroperitoneal involvement (RPI) with local control (N-stage: P=0.0155; RPI:P =0.0295), a significant correlation between maximum tumor size and metastases-free survival (P=0.0167) and overall survival (P=0.0241); the female gender was another predictor of prolonged survival (P= 0.0465). Multivariate analysis (Cox) showed a significant impact of N-stage and retroperitoneal involvement on local control and also a significant correlation between perineural involvement and tumor diameter with metastases-free survival.

CONCLUSIONS

These results are similar to those of other published series and suggest that this approach is feasible with acceptable local control and survival, especially in patients with small tumors (<2.5 cm: 5 year survival=33.3%) and in female patients (5 year survival=30%). Due to the impact of gender, tumor diameter and N stage on prognosis, in the design of future trials a stratification of patients based on these categories should be considered. The search of effective chemotherapeutic agents is required, to reduce the high incidence of distant metastases, especially in larger tumors.

Adjuvant therapy in pancreatic cancer

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.

[Therapy of pancreatic adenocarcinoma]

BACKGROUND

Despite significant advances in the areas of epidemiology, risk factors, molecular genetics and diagnosis pancreatic carcinoma is characterized by a dismal prognosis and ranks 5th among malignancy-associated deaths. This article attempts to critically review the current literature and analyze therapeutic recommendations based on published evidence. Therapeutic options are based on the stage of the disease.

SURGICAL TREATMENT

Surgical resection with curative intention is feasible only in a minority of patients presenting with locally confined tumor disease. RADIO- AND CHEMOTHERAPY: Adjuvant combined radiochemotherapy might potentially improve survival and can also be considered in unresectable, locally advanced disease. The role of chemotherapy in advanced disease is exclusively palliative. Up to now, no chemotherapeutic regimen has demonstrated convincing impact on survival. Newer substances, such as gemcitabine, appear to be of some value in respect to quality of life. Best supportive care oriented at clinical symptoms remains a cornerstone in the therapeutic concept of patients with pancreatic carcinoma.

CONCLUSION

Development of innovative therapeutic strategies is therefore mandatory.

The novel Trk receptor tyrosine kinase inhibitor CEP-701 (KT-5555) exhibits antitumor efficacy against human pancreatic carcinoma (Panc1) xenograft growth and in vivo invasiveness

The survival rate for patients with pancreatic ductal adenocarcinoma (PDAC) is among the poorest for all cancers. The factors that contribute to this poor prognosis are lack of effective early detection, high rate of metastases and a generally refractory response to available treatment modalities. The most commonly used treatment methods--chemotherapy and radiation therapy--are mainly used for symptom palliation, with surgery being the only "curative" treatment option. The use of combinations of treatment modalities is the only therapy available to patients with locally advanced disease or that which is surgically unresectable. These options are still not sufficient to increase patient survival time significantly. The aggressive behavior and poor prognosis of this cancer is associated with an increased expression of many growth factors and their cognate receptors. We have demonstrated previously the aberrant expression of the Trk receptors (Trks A, B, and C) in PDAC specimens and human PDAC-derived cell lines and a biphasic, dose-dependent response of specific neurotrophic agents on the in vitro invasiveness of PDAC cells. Based on these data we have evaluated the therapeutic potential of inhibiting neurotrophin-Trk interactions using a selective Trk tyrosine kinase inhibitor (CEP-701) on subcutaneous (s.c.) and tracheal xenografts derived from the poorly differentiated PDAC cell line, Panc1. We demonstrate that CEP-701 administration at 10 mg/kg s.c. BID for 21 days inhibited tumor growth of the Panc1 s.c. xenografts in a statistically-significant manner (p < 0.01) compared to vehicle controls, in the absence of morbidity and mortality. A T/C value of 25% was observed for CEP-701-treated s.c. xenografts. In addition, CEP-701 administration inhibited tumor cell invasion in the s.c. tracheal xenograft model of in vivo invasiveness. Taken together, these data suggest that further studies are warranted to evaluate CEP-701 as a potential therapeutic agent in the treatment of PDAC.