Postoperative bleeding complications after gastric cancer surgery in patients receiving anticoagulation and/or antiplatelet agents

BACKGROUND

Perioperative antithrombotic treatment for gastric cancer patients receiving chronic anticoagulation and/or antiplatelet agents requires an understanding of potential bleeding and thromboembolic risks. However, no study has examined the safety aspects of perioperative antithrombotic treatment during radical gastrectomy. This study sought to evaluate postoperative bleeding and thromboembolic complications after radical gastrectomy in patients undergoing perioperative antithrombotic treatment.

METHODS

The medical records of patient treated by radical gastrectomy from January 2006 to December 2010 were retrospectively reviewed. Those in the thromboprophylaxis group had received one of three regimens of perioperative antithrombotic treatment according to the clinical indications of chronic anticoagulation and/or antiplatelet agents and several published evidence-based recommendations: (1) bridging therapy with unfractionated heparin; (2) continuation of aspirin; or (3) both 1 and 2. multivariate analysis was used to identify risk factors for postoperative bleeding complications after radical gastrectomy.

RESULTS

During the study period, 340 patients underwent radical gastrectomy. Of these, 62 patients received perioperative antithrombotic treatment; this thromboprophylaxis group had a significantly higher postoperative bleeding rate (8.1 vs. 0.7 %, P = 0.003). However, other complications, including thromboembolic events, were similar in the two study groups. Multivariate analysis revealed that perioperative antithrombotic treatment was the only independent risk factor of postoperative bleeding complications after radical gastrectomy (odds ratio, 8.53; 95 % confidence interval, 1.47-49.39; P = 0.017).

CONCLUSIONS

Perioperative antithrombotic treatment is an independent risk factor of postoperative bleeding complications in patients with gastric cancer undergoing radical gastrectomy, although such treatment was effective in preventing postoperative thromboembolic events.

An adequate perioperative management and strategy for gastric cancer after coronary artery bypass using the right gastroepiploic artery

PURPOSE

Interruption of the right gastroepiploic artery (RGEA) used for prior coronary artery bypass grafting (CABG) may cause life-threatening myocardial ischemia during gastrectomy. This study investigated the cases treated in this department and pooled data in the literature to identify an adequate perioperative RGEA management strategy.

METHODS

Eight patients underwent gastrectomy after CABG with the RGEA. This study examined conditions, management of the RGEA, No. 6 lymph node metastasis, and complications of these cases and those in the pooled data.

RESULTS

Percutaneous coronary intervention or a redo CABG was performed in advance in 7 and 1 patients, respectively. The RGEA was resected for dissection of No. 6 lymph nodes in 6 patients. Five patients had lymph node metastasis. Thirty-seven patients from 40 combined cases (92.5 %) underwent total or distal gastrectomy, but 17 patients (42.5 %) had RGEA resection. Resections of the RGEA and No. 6 lymph node metastasis were significantly higher in patients with perioperative coronary management than in those without such management.

CONCLUSION

Coronary and celiac angiography and coronary revascularization are prerequisites to prevent cardiac events during gastrectomy and dissection of No. 6 lymph nodes should be performed with resection of RGEA. Standard lymph node dissection should therefore be performed with a curative intent for all patients even those undergoing gastrectomy after CABG using RGEA.

P4-05-05: Imaging Mass Spectrometry Based Lipid Metabolites Analysis for Breast Cancer

Background: Activation of lipid metabolism is an early event of carcinogenesis and a central hallmark of many cancers including breast cancer. Recent findings argue that stearoyl CoA desaturase-1 (SCD1), a key regulator of the fatty acid (FA) composition and the endoplasmic reticulum resident enzyme that converts saturated FA (SFA) into monounsaturated FA (MUFA) is a novel regulator of carcinogenesis. The distinctive lipids composition of membrane in cancer cells and the biological functions of SCD1, however, still remain uncertain. Imaging mass spectrometry (IMS) is a mass spectrometry-based analyzing technique that enables visualization of the individual molecules without requiring antibodies. It allows comprehensive detection of a wide range of biomolecules, such as lipids. We attempted to visualize the localization of lipids in breast cancer by IMS for better understanding of cancer proliferation.

Materials and methods: 13 specimens were obtained from the primary breast cancer patients. All were Japanese woman and aged 41–86 years (mean 61.5y.o.). Only one patient received preoperative systematic therapy. 6 were estrogen receptor (ER) and/or progesterone receptor (PgR) positive and human epidermal growth factor receptor 2 (HER2) negative, 2 were ER and/or PgR positive and HER2 positive, 2 were both ER and PgR negative and HER2 positive and 2 were triple negative.

IMS: Samples were immediately chilled in liquid Hexan and stored at −80°. All specimens were sliced into 10 mm thin sections, mounted onto one indium-tin oxide-coated glass slides (Bruker Daltonics) and then sprayed by 2,5-Dihydroxybenzoic acid. Matrix assisted laser desorption ionization (MALDI) technique was used as a soft ionization method. We used time of flight (TOF)/TOF type instrument (Ultraflex, Bruker Daltonics) and all the spectrum were acquired automatically using Fleximaging software (Bruker Daltonics). Each spectral intensity at any mass-to-charge ratio (m/z) was measured at 16 regions of interest (ROI); 13 ROI were picked up from cancerous parts and 3 were from non-cancerous parts. Spectral intensities were compared and statistical analysis was performed by Mann Whitney test. The software was also used to create two-dimensional ion-density maps.

Results: In the cancerous parts of all the 13 specimens, two distinct peaks of the molecular ions were detected at m/z 798.5 and 810.5, which were not found in the non-cancerous parts. Median intensity of the molecular ions at m/z 798.5 and 810.5 were 38.9 and 3.18 in the cancerous part, while they were 0.84 and 1.02 in the non-cancerous part (p=0.010 and 0.015, respectively). Tandem mass spectrometry analysis for these two molecules revealed that they were two kinds of phosphatidylcholine (PC), PC (16:0/18:1) and PC (18:0/18:1). Localization of the individual PC was visualized by means of IMS, which showed that in cancerous part accumulation of PCs containing MUFA was more pronounced than those containing SFA only. Conclusion:

Two kinds of PC containing MUFA were found to highly accumulate in cancerous parts, which may suggest involvement of SCD1 in the membrane composition regulation and cancer proliferation. Further studies may thus be warranted to explore the relation between PC localization and the SCD1 expression.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-05-05.

OT2-03-03: Spectroscopic Feature of Breast Cancer

Objectives: To examine optical properties of breast cancer by time-resolved spectroscopy.

Materials and Methods: We irradiated a pulsed laser of 760, 800, and 830 nm wave-length lights at multiple sites of both breasts including the site just above the cancer and detected the light transmitted through the breast with TRS-20SH (Hamamatsu Photonics K.K.). Absorption coefficient (μa), reduced scattering coefficient (μs'), total hemoglobin (tHb), and oxygen saturation (SO2) of the breast were calculated by photon diffusion equation. The clinical trial started in January 2007. A total of one hundred nine breast cancer patients participated in the trial and written informed consent were obtained from all of the patients. Results: In 800 nm wave-length, absorption coefficient (μa) of breast cancer tissue was significantly high, compared with contra-lateral normal breast (cancer:0.0677± 0.0293, normal breast;0.0479± 0.0161, p<0.001).

Giant Rashba-type spin splitting in bulk BiTeI

There has been increasing interest in phenomena emerging from relativistic electrons in a solid, which have a potential impact on spintronics and magnetoelectrics. One example is the Rashba effect, which lifts the electron-spin degeneracy as a consequence of spin-orbit interaction under broken inversion symmetry. A high-energy-scale Rashba spin splitting is highly desirable for enhancing the coupling between electron spins and electricity relevant for spintronic functions. Here we describe the finding of a huge spin-orbit interaction effect in a polar semiconductor composed of heavy elements, BiTeI, where the bulk carriers are ruled by large Rashba-like spin splitting. The band splitting and its spin polarization obtained by spin- and angle-resolved photoemission spectroscopy are well in accord with relativistic first-principles calculations, confirming that the spin splitting is indeed derived from bulk atomic configurations. Together with the feasibility of carrier-doping control, the giant-Rashba semiconductor BiTeI possesses excellent potential for application to various spin-dependent electronic functions.

Surgical outcomes and survival after extended multiorgan resection for T4 gastric cancer

BACKGROUND

Extended multiorgan resection (EMR) for locally advanced (T4) gastric cancer remains controversial. The aim of this study was to evaluate the effectiveness of this approach with regard to morbidity, mortality, and survival.

METHODS

Between 2005 and 2009, 41 patients underwent aggressive surgery for clinical T4 gastric cancer. Univariate and multivariate analyses were used to identify prognostic factors for surgical outcomes and survival in these patients.

RESULTS

Curative resection was performed in 29 patients (70.7%); postoperative morbidity and mortality rates were 17.1% and 4.9%, respectively. The survival rate in R0 resection patients was significantly longer than that in patients undergoing R1 or R2 resection. Multivariate analysis identified resectability and tumor size (≥10 cm) as independent prognostic factor for patients with T4 gastric cancer undergoing combined resection.

CONCLUSIONS

EMR should be performed for patients with T4 gastric cancer in whom curative resection can be used.

A fibrin adhesive sealing method for the prevention of pancreatic fistula following distal pancreatectomy

BACKGROUND/AIMS

Pancreatic fistula is the most common complication following distal pancreatectomy. We have developed a fibrin adhesive sealing method which covers the cut surface and parenchyma of the pancreas, to prevent pancreatic fistula.

METHODOLOGY

We performed 25 distal pancreatectomies. Fibrin adhesive (TachoComb) was applied to the staple line of the pancreas before stapling. Pancreatic fistula was defined and graded according to the International Study Group of Postoperative Pancreatic Fistula (ISGPF) definition.

RESULTS

The overall incidence of pancreatic fistula was five cases (20%). Four cases (16%) were classified as Grade A. Only one case (4%) was classified as Grade B. In patients with or without pancreatic fistula, the mean length of postoperative hospital stay was not significant.

CONCLUSIONS

The fibrin adhesive sealing method is a simple and effective method of preventing postoperative pancreatic fistula formation after distal pancreatectomy.

[Efficacy of chemotherapy combined with dissection of para-aortic lymph node metastasis following gastric cancer surgery -- case report]

A 64-year-old man visited our hospital complaining of epigastric pain. An upper gastrointestinal endoscopy revealed a type 2 gastric cancer at the lower portion of the lesser curvature of the stomach. We performed a distal gastrectomy with D2 dissection. The histopathological diagnosis was well-differentiated tubular adenocarcinoma, mp, ly2, v0, n2(+), No. 11p(1/ 1), Stage III a.We used postoperative chemotherapy with a combination of S-1(80 mg/body)and low-dose cisplatin(10mg/ body × 10 days). After 1 course, we continued only S-1(80 mg/body)for 3 weeks followed by a 2-week interval. About 1 year after the operation, the CEA value was abnormally high. An abdominal CT scan showed a marked swelling of the paraaortic lymph node. The patient was then treated with the same protocol of S-1 and cisplatin again, but the CEA value did not decrease; therefore, a para-aortic lymph node dissection(No. 16a2b1 latero)was performed. Although the CEA value had decreased to normal, a few months later it was high again, and so we increased the S-1 dosage from 80 mg/body to 100mg/ body. But 6 months after the first para-aortic lymph node dissection, positron emission tomography(PET)revealed a swelling of paraaortic lymph node below the first recurrence site again. We changed the postoperative chemotherapy from S-1 and cisplatin to S-1(100mg/body)and irinotecan(80 mg/m² day 1, 8). Since the CEA value was not decreased, we performed a second para-aortic lymph node dissection(No. 16b1b2 latero)13 months after the first dissection. The patient is presently alive with no signs of recurrence after over 1. 5 years. Para-aortic lymph node dissection combined with postoperative chemotherapy appeared to be effective for para-aortic lymph node metastasis in this case.

Effect of transplantation of pro-angiogenic monocytes to pancreatic cancer-bearing mice on resistance to chemotherapy/radiotherapy

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Background: Hypoxic tumors are usually resistant to conventional chemotherapy and radiotherapies, which typically target actively dividing cells. The tumor vasculatures are unorganized and lack adequate pericyte coverage, which compromises delivery of drugs to tumors. How best to normalize the aberrant tumor vasculature to maximize anticancer drug delivery comprises an area of intensive investigation.

Methods: We tested out hypothesize that bone marrow (BM) cells may be able to restore appropriate vessel function in tumor vasculature using nude mice bearing pancreatic cancer xenografts and genetically engineered mice that develop pancreatic adenocarcinoma.

Results: Culturing BM mononuclear cells with endothelial growth medium resulted in the early outgrowth of spindle-shaped attached monocytic cells expressing CD11b/CXCR4 with a significant vessel stabilizing activity. Intravenous administration of these cultured pro- angiogenic cells into mice bearing pancreatic cancer significantly reduced areas of hypoxia without enhancing tumor growth. The resulting vasculature structurally mimicked normal vessels with intensive pericyte coverage. Consistent with a marked reduction in gene expressions involved in drug resistance such as MDR1 and ABCG2 in monocytes-injected tumors, a combination of the transplantation and chemotherapeutic agents reduced tumor size and significantly increased areas of necrosis as compared to chemotherapy alone.

Conclusions: Our findings offer an alternate approach to improve delivery and efficacy of anticancer drugs to hypoxic tumors through a remodeling of the abnormal tumor vessels.

No significant financial relationships to disclose.

Pancreaticojejunostomy using a fibrin adhesive sealant (TachoComb) for the prevention of pancreatic fistula after pancreaticoduodenectomy

BACKGROUND/AIMS

Pancreatic fistula is a common complication following pancreaticoduodenectomy. A number of technical modifications aimed to improve the pancreato-enteric anastomosis technique have been reported. The aim of this study was to evaluate the safety of TachoComb fibrin adhesive as a sealing method in duct-to-mucosa pancreaticojejunostomy after pancreaticoduodenectomy.

METHODOLOGY

Between 2005 to 2009, 40 patients (28 men and 12 women) underwent duct-to-mucosa pancreaticojejunostomy using a fibrin adhesive (TachoComb) sealing method after pancreaticoduodenectomy (either pylorus-preserving or modified Child's methods). The mean age was 67.9 years (range of 49 to 80 years).

RESULTS

The overall postoperative rates of mortality and morbidity were 0.0% and 35.0%, respectively. Following the classification system described by the International Study Group on Pancreatic Fistula, 5 patients (12.5%) had Grade A pancreatic fistulas and 3 patients (7.5%) had Grade B pancreatic fistulas. There were no patients with Grade C pancreatic fistulas, and no cases of postoperative hemorrhage. No significant difference in the length of postoperative hospital stay was observed in patients with or without pancreatic fistulas.

CONCLUSIONS

The use of TachoComb fibrin adhesive as a sealing method in duct-to-mucosa pancreaticojejunostomy is safe, reliable for the prevention of pancreatic fistula, and shows promise for all types of reconstruction following pancreaticoduodenectomy.

Gemcitabine and s-1 combination chemotherapy in patients with advanced biliary tract cancer: a retrospective study

Background

The aim of this study was to investigate the efficacy and safety of gemcitabine and S-1 combination chemotherapy in patients with advanced biliary tract cancer.

Patients and Methods

A retrospective study was performed on 15 consecutive patients. Gemcitabine was administered intravenously at 1,000 mg/m² on days 8 and 15. Oral S-1 (60 mg/m² in 2 divided doses) was given daily for the first 2 weeks, followed by 1 week of rest. This 3-week course of treatment was repeated. The primary endpoint was response rate, and the secondary endpoints were overall survival, progression-free survival, and safety.

Results

The overall response rate was 26.7%, and the disease control rate was 73.4%. The overall survival was 12.0 months (95% CI, 9.5–14.5 months), and the progression-free survival was 8.0 months (95% CI, 4.3–11.7 months). Adverse events of grade 3 or 4 occurred in 33.3%, and the major grade 3/4 toxicities were anemia (20.0%), leukopenia (13.3%), and anorexia (13.3%).

Conclusion

Gemcitabine and S-1 combination chemotherapy is effective and safe in patients with advanced biliary tract cancer.

A case of non-traumatic subgaleal hematoma effectively treated with endovascular surgery

Non-traumatic subgaleal hematoma is very rare. We present a case of refractory non-traumatic subgaleal hematoma occurring in a 15-year-old male patient. The patient was successfully treated by embolization of the superficial temporal artery. This therapeutic approach to refractory non-traumatic subgaleal hematoma is discussed.

EMX2 is epigenetically silenced and suppresses growth in human lung cancer

Lung cancer is a common cancer and the leading cause of cancer-related death worldwide. Aberrant activation of WNT signaling is implicated in lung carcinogenesis. EMX2, a human homologue of the Drosophila empty spiracles gene is a homeodomain-containing transcription factor. The function of EMX2 has been linked to the WNT signaling pathway during embryonic patterning in mice. However, little is known about the role of EMX2 in human tumorigenesis. In this study, we found that EMX2 was dramatically downregulated in lung cancer tissue samples and this downregulation was associated with methylation of the EMX2 promoter. Restoration of EMX2 expression in lung cancer cells lacking endogenous EMX2 expression suppressed cell proliferation and invasive phenotypes, inhibited canonical WNT signaling, and sensitized lung cancer cells to the treatment of the chemo cytotoxic drug cisplatin. On the other hand, knockdown of EMX2 expression in lung cancer cells expressing endogenous EMX2 promoted cell proliferation, invasive phenotypes and canonical WNT signaling. Taken together, our study suggests that EMX2 may have important roles as a novel suppressor in human lung cancer.

Transplanting normal vascular proangiogenic cells to tumor-bearing mice triggers vascular remodeling and reduces hypoxia in tumors

Blood vessels deliver oxygen and nutrients to tissues, and vascular networks are spatially organized to meet the metabolic needs for maintaining homeostasis. In contrast, the vasculature of tumors is immature and leaky, resulting in insufficient delivery of nutrients and oxygen. Vasculogenic processes occur normally in adult tissues to repair "injured" blood vessels, leading us to hypothesize that bone marrow mononuclear cells (BMMNC) may be able to restore appropriate vessel function in the tumor vasculature. Culturing BMMNCs in endothelial growth medium resulted in the early outgrowth of spindle-shaped attached cells expressing CD11b/Flt1/Tie2/c-Kit/CXCR4 with proangiogenic activity. Intravenous administration of these cultured vascular proangiogenic cells (VPC) into nude mice bearing pancreatic cancer xenografts and Pdx1-Cre;LSL-Kras(G12D);p53(lox/+) genetically engineered mice that develop pancreatic ductal adenocarcinoma significantly reduced areas of hypoxia without enhancing tumor growth. The resulting vasculature structurally mimicked normal vessels with intensive pericyte coverage. Increases in vascularized areas within VPC-injected xenografts were visualized with an ultrasound diagnostic system during injection of a microbubble-based contrast agent (Sonazoid), indicating a functional "normalization" of the tumor vasculature. In addition, gene expression profiles in the VPC-transplanted xenografts revealed a marked reduction in major factors involved in drug resistance and "stemness" of cancer cells. Together, our findings identify a novel alternate approach to regulate abnormal tumor vessels, offering the potential to improve the delivery and efficacy of anticancer drugs to hypoxic tumors.

Incidence of synchronous and metachronous pancreatic carcinoma in 168 patients with branch duct intraductal papillary mucinous neoplasm

BACKGROUND/AIMS

Although branch duct intraductal papillary mucinous neoplasms of the pancreas (BD-IPMN) are being diagnosed with increasing frequency, the incidence of concomitant pancreatic carcinoma (PC) is not well known. We investigated the incidence and clinical features of synchronous and metachronous PC in patients with BD-IPMN.

METHODS

We studied 168 BD-IPMN patients diagnosed by various imaging modalities, including endoscopic retrograde pancreatography, between 1990 and 2008. We reviewed the medical records and clinical features in both patients developing and not developing PC. The diagnosis of PC was histologically verified in all patients.

RESULTS

PC was observed in 9 (5.4%) of 168 patients. Five were synchronously detected at the time of BD-IPMN diagnosis, whereas four were metachronously identified during the follow-up period. All PCs occurred in regions separate from the BD-IPMN lesion. All PCs represented histologically invasive ductal adenocarcinomas, whereas the BD-IPMN lesion was diagnosed as adenoma. Patients developing PC were significantly older than patients not developing PC (p = 0.017). The diameters of the BD-IPMN lesions and main pancreatic ducts were significantly smaller in patients developing PC than patients not developing PC (p = 0.013 and p < 0.001, respectively).

CONCLUSIONS

It was not infrequent for PC to occur in the pancreas with BD-IPMN. Particular attention should therefore be paid to the development of PC, even in low-risk BD-IPMN, as well as to changes in BD-IPMN.

[A case of pancreatic carcinoma presenting as pancreaticopleural fistula with pancreatic pleural effusion]

A 63-year-old man was admitted with left pleural effusion, and an amylase level of 30994IU/l. A diagnosis of pancreaticopleural fistula was made, based on the findings of magnetic resonance cholangiopancreatography and endoscopic retrograde pancreatography (ERP). After the placement of an endoscopic naso-pancreatic drainage tube, the pleural effusion markedly reduced. When ERP was performed for internal drainage, the main pancreatic duct and stricture were biopsied and showed pancreatic ductal adenocarcinoma histologically. CT revealed a mass in the head of the pancreas. He underwent pylorus-preserving pancreaticoduodenectomy. To the best of our knowledge this is the first case of pancreatic carcinoma presenting as pancreaticopleural fistula with pancreatic pleural effusion. Clinicians should pay attention to the possible presence of cancer and pancreaticopleural fistula in patients with pancreatic pleural effusion.

Expression of a Rho guanine nucleotide exchange factor, Ect2, in the developing mouse pituitary

The pituitary gland is a highly mitotically active tissue after birth. Various cell types are known to undergo proliferation in the anterior pituitary. However, little is known about the mechanisms regulating mitotic activity in this tissue. When searching for genes specifically expressed in the pituitary gland among those that we previously screened in Drosophila, we found epithelial cell-transforming gene 2 (Ect2). Ect2 is a guanine nucleotide exchange factor for Rho GTPases, which is known to play an essential role in cytokinesis. Although there have been many cellular studies regarding the function of Ect2, the temporal and spatial expression patterns of Ect2 in vivo have not been determined. In the present study, we examined the postnatal developmental expression of Ect2 in the mouse pituitary. Enhanced Ect2 expression was detected in the mouse pituitary gland during the first 3 weeks after birth, which coincided well with the period of rapid pituitary expansion associated with increased growth rate. Immunostaining analysis showed that Ect2-expressing cells were distributed in the anterior and intermediate lobes, but not the posterior lobe, of the pituitary. These Ect2-expressing cells frequently incorporated the thymidine analogue, EdU (5-ethynyl-2'-deoxyuridine), indicating that these cells were mitotically active. Taken together, the results demonstrate the functional role of Ect2 in postnatal proliferating cells in the two lobes of the pituitary, thereby suggesting roles in developmental growth of the mammalian pituitary.

Abstract 3440: Activation of hedgehog pathway in tumor vasculature is a late event of pancreatic tumorigenesis

Bone marrow cells can be activated to function as instigators of tumor growth by systemic tumor-derived signals. We have identified subsets of BM cells that regulate neovascularization in pancreatic ductal adenocarcinoma (PDAC). Notably, blockade of Hedgehog (Hh) signaling markedly destabilized neovessels in PDAC xenografts by attenuating the homing and incorporation of the BM-derived cells into the neovasculature. We found IGF-1 production in the tumor stroma was regulated by the Hh ligand, Shh, and played a key role during this process. In vitro co-culture experiments demonstrated that human PDAC cell lines induced IGF-1 in c-Kit+ BM derived mononuclear cells utilized as pro-angiogenic cells, and that the induction was attenuated either by cyclopamine or expression of shRNA targeting Smo in the mononuclear cells. Shh secreted from PDAC cells induced tube formation by the mouse endothelial line MS-1, suggesting an important role for Shh in migration and capillary formation of the BM-derived pro-angiogenic cells; this induction of capillary morphogenesis was blocked by anti-IGF-1 neutralizing antibody. The “paracrine” effect of Hh seems to be a late event during pancreatic tumorigenesis, as full length Gli2 expression in neovasculatures was detected within PDAC lesions, but not in precursor PanIN lesions using a genetically engineered mouse models. We also observed upregulation of VE-cadherin, Id1, and Ptch1 mRNA in lineage-/c-Kit+ fraction of BM mononuclear cells from PDAC mice as compared to control mice or mice with PanIN, suggesting that pro-angiogenic conditions induced at the level of the BM in cancer-bearing hosts. The primitive progenitors derived from ‘activated BM’ are imported to the tumor microenvironment where they become fully activated. Overall, these studies provide insights into the cellular and molecular mechanisms by which BM-derived cells promote tumor growth and angiogenesis and have implications for the design of anti-angiogenesis therapies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3440.

Hedgehog promotes neovascularization in pancreatic cancers by regulating Ang-1 and IGF-1 expression in bone-marrow derived pro-angiogenic cells

Background

The hedgehog (Hh) pathway has been implicated in the pathogenesis of cancer including pancreatic ductal adenocarcinoma (PDAC). Recent studies have suggested that the oncogenic function of Hh in PDAC involves signaling in the stromal cells rather than cell autonomous effects on the tumor cells. However, the origin and nature of the stromal cell type(s) that are responsive to Hh signaling remained unknown. Since Hh signaling plays a crucial role during embryonic and postnatal vasculogenesis, we speculated that Hh ligand may act on tumor vasculature specifically focusing on bone marrow (BM)-derived cells.

Methodology/Principal Findings

Cyclopamine was utilized to inhibit the Hh pathway in human PDAC cell lines and their xenografts. BM transplants, co-culture systems of tumor cells and BM-derived pro-angiogenic cells (BMPCs) were employed to assess the role of tumor-derived Hh in regulating the BM compartment and the contribution of BM-derived cells to angiogenesis in PDAC. Cyclopamine administration attenuated Hh signaling in the stroma rather than in the cancer cells as reflected by decreased expression of full length Gli2 protein and Gli1 mRNA specifically in the compartment. Cyclopamine inhibited the growth of PDAC xenografts in association with regression of the tumor vasculature and reduced homing of BM-derived cells to the tumor. Host-derived Ang-1 and IGF-1 mRNA levels were downregulated by cyclopamine in the tumor xenografts. In vitro co-culture and matrigel plug assays demonstrated that PDAC cell-derived Shh induced Ang-1 and IGF-1 production in BMPCs, resulting in their enhanced migration and capillary morphogenesis activity.

Conclusions/Significance

We identified the BMPCs as alternative stromal targets of Hh-ligand in PDAC suggesting that the tumor vasculature is an attractive therapeutic target of Hh blockade. Our data is consistent with the emerging concept that BM-derived cells make important contributions to epithelial tumorigenesis.