Roderich E. Schwarz

Targeting Endogenous Transforming Growth Factor β Receptor Signaling in SMAD4-Deficient Human Pancreatic Carcinoma Cells Inhibits Their Invasive Phenotype 1

Transforming growth factor-β (TGF-β) suppresses tumor formation by blocking cell cycle progression and maintaining tissue homeostasis. In pancreatic carcinomas, this tumor suppressive activity is often lost by inactivation of the TGF-β-signaling mediator, Smad4. We found that human pancreatic carcinoma cell lines that have undergone deletion of MADH4 constitutively expressed high endogenous levels of phosphorylated receptor-associated Smad proteins (pR-Smad2 and pR-Smad3), whereas Smad4-positive lines did not. These elevated pR-Smad levels could not be attributed to a decreased dephosphorylation rate nor to increased expression of TGF-β type I (TβR-I) or type II (TβR-II) receptors. Although minimal amounts of free bioactive TGF-β1 and TGF-β2 were detected in conditioned medium, treatment with a pan-specific (but not a TGF-β3 specific) TGF-β-neutralizing antibody and with anti-αVβ6 integrin antibody decreased steady-state pSmad2 levels and activation of a TGF-β-inducible reporter gene in neighboring cells, respectively. Thus, activation of TGF-β at the cell surface was responsible for the increased autocrine endogenous and paracrine signaling. Blocking TβR-I activity using a selective kinase inhibitor (SD-093) strongly decreased the in vitro motility and invasiveness of the pancreatic carcinoma cells without affecting their growth characteristics, morphology, or the subcellular distribution of E-cadherin and F-actin. Moreover, exogenous TGF-β strongly stimulated in vitro invasiveness of BxPC-3 cells, an effect that could also be blocked by SD-093. Thus, the motile and invasive properties of Smad4-deficient pancreatic cancer cells are at least partly driven by activation of endogenous TGF-β signaling. Therefore, targeting the TβR-I kinase represents a potentially powerful novel therapeutic approach for the treatment of this disease.

An antiendothelial combination therapy strategy to increase survival in experimental pancreatic cancer

BACKGROUND Combination treatments in addition to gemcitabine have failed to improve outcomes in pancreatic cancer. We tested gemcitabine in combination with the antiendothelial agent endothelial monocyte-activating polypeptide II (EMAP II). METHODS Human pancreatic cancer cell line murine xenografts were treated with recombinant EMAP II (80 mug/kg), gemcitabine (100 mg/kg), or a combination, and survival and local tumor outcomes were studied. RESULTS Both EMAP II and gemcitabine inhibited tumor growth, but the combination of both was always more effective. EMAP II and gemcitabine also inhibited microvessel density, with the combination being more effective. Apoptotic activity was increased by factors of 3.2-, 2.7-, and 4.2-fold in EMAP II, gemcitabine, or their combination, respectively. There was a significant extension of survival after EMAP II and gemcitabine combination therapy compared with controls in 2 different pancreatic cancer cell line models at P = .0001 and P = .006, respectively. The median EMAP II survival contribution over gemcitabine was 16 days, from 35 to 51 days (P = .017). EMAP II had no impact on gemcitabine-induced antiproliferative effects against pancreatic cancer cells in vitro. CONCLUSION The antiendothelial agent EMAP II enhanced gemcitabine-mediated tumor inhibition, pointing toward a promising strategy for improved combination treatment of pancreatic cancer.

Gastric adenomyoma: Definitely benign or defiantly premalignant?

A 52-year-old woman with epigastric pain is presented, who was found to have a 5-cm antral wall mass. The distal gastrectomy specimen revealed a benign-appearing prepyloric adenomyoma, without pancreatic elements. Although the cancer risk for gastric hamartomatous adenomyomas is generally considered low, the potential for malignant degeneration exists and is discussed in relation to the Helicobacter pylori infection of this case. In order to achieve diagnostic certainty and optimal symptom control, complete operative resection is recommended whenever feasible.

In vivo monotherapy and combination treatment of pancreatic cancer with the antiendothelial agent EMAP-II

S: PLENARY and PARALLEL SESSIONS 5O Systemic administration of an anti-VEGF monoclonal antibody inhibits growth of human pancreatic adenocarcinoma in an orthotopic mouse model S.E. Holloway,* A. Beck, M. Davis, T. Hart, R.A. Brekken, J.B. Fleming. University of Texas Southwestern Medical

Long-term survival after radical operations for cancer treatment-induced sarcomas: How two survivors invite reflection on oncologic treatment concepts

Extent and radicality of surgical oncologic treatment has changed in the past 30 years. Two patients with node-positive breast cancer are presented, who underwent (total or radical) mastectomy with lymphadenectomy and postoperative radiation 24 and 40 years ago. A radiation-associated sarcoma of the parascapular soft tissue developed in one patient 9 years after treatment; the other one sought treatment for a lymphedema-associated Stewart-Treves lymphangiosarcoma 16 years after initial therapy. Both patients underwent a forequarter amputation for their treatment-associated high-grade sarcoma. Both are currently alive and cancer-free 15 and 24 years after amputation. These reports remind us that radical locoregional treatment can cure some solid cancers in the absence of systemic therapy; that such extensive treatment may induce significant disability or secondary malignancies long-term; that even advanced treatment-associated sarcomas can be cured with aggressive resection; that today’s multimodality therapy approaches and appropriate patient selection have rendered such extensive locoregional treatment for many tumors obsolete or unnecessary; and that if no effective alternative treatment exists and organ or limb preservation is not feasible, an aggressive resection approach for high-grade cancer should not be discounted unless systemic failure is certain or imminent.