Herceptin and gemcitabine for metastatic pancreatic cancers that overexpress HER-2/neu

Lapatinib/gemcitabine and lapatinib/gemcitabine/oxaliplatin: a phase I study for advanced pancreaticobiliary cancer

OBJECTIVE

To evaluate the safety/tolerability and potential antitumor activity of lapatinib, at dose ranges of 1000 to 1500 mg/d, in combination with gemcitabine and gemcitabine/oxaliplatin (GEMOX) in patients with advanced pancreaticobiliary cancer.

MATERIALS AND METHODS

Patients with advanced pancreaticobiliary cancer were assigned to 1 of 4 cohorts of lapatinib administered once daily. Toxicities, response, and survival were assessed.

RESULTS

Twenty-five patients were enrolled, 18 with pancreatic cancer and 7 with biliary cancer. Lapatinib, 1500 mg/d, was successfully administered with weekly gemcitabine. Dose limiting toxicities of nausea and anorexia occurred in 2 of 5 patients receiving 1500 mg/d lapatinib with GEMOX. The median survival of all patients was 11 months and the 1-year survival was 48%.

CONCLUSION

Lapatinib, 1500 mg/d, can be administered with weekly gemcitabine. The maximum tolerated dose of lapatinib is 1000 mg/d with GEMOX. A phase II study of lapatinib and gemcitabine for metastatic pancreatic cancer will be initiated.

Pancreatic cancer: from molecular signature to target therapy

Pancreatic adenocarcinoma is a leading cause of cancer death in western countries. The treatment of advanced disease with gemcitabine has only a modest activity on survival with a favourable impact on quality of life. However, recent data support the evidence that the combination of gemcitabine with erlotinib, capecitabine or platinum compounds could be more active than gemcitabine alone in advanced pancreatic cancer. New therapeutic strategies, particularly using molecular target agents, are under evaluation. A number of molecular mechanisms responsible of transformation and progression of pancreatic cancer have been identified, opening the possibility to identify also possible pharmacological targets. A promising approach is the pharmacological inhibition of tumor angiogenesis with anti-vascular endothelial growth factor (VEGF) agents, such as bevacizumab, cyclooxygenase-2 inhibitors (celecoxib), thalidomide and others. Also epidermal growth factor receptor (EGFR) plays an important role in progression of pancreatic cancer. Erlotinib, an oral available anti-EGFR compound, was the first agent capable to significantly improve overall survival in a phase III trial, leading to its approval by Food and Drug Administration (FDA) in combination with gemcitabine as first-line therapy. Ongoing studies are exploring the role of targeted therapy in the adjuvant setting. However, despite these promising results, several questions remain to be resolved, including the rational selection of the patients who are more likely to obtain benefit of target therapy, the choice of the optimal therapeutic schedule of therapy, the clinical setting of choice, and the management of the toxicity.

The ERBB3 receptor in cancer and cancer gene therapy

ERBB3, a member of the epidermal growth factor receptor (EGFR) family, is unique in that its tyrosine kinase domain is functionally defective. It is activated by neuregulins, by other ERBB and nonERBB receptors as well as by other kinases, and by novel mechanisms. Downstream it interacts prominently with the phosphoinositol 3-kinase/AKT survival/mitogenic pathway, but also with GRB, SHC, SRC, ABL, rasGAP, SYK and the transcription regulator EBP1. There are likely important but poorly understood roles for nuclear localization and for secreted isoforms. Studies of ERBB3 expression in primary cancers and of its mechanistic contributions in cultured cells have implicated it, with varying degrees of certainty, with causation or sustenance of cancers of the breast, ovary, prostate, certain brain cells, retina, melanocytes, colon, pancreas, stomach, oral cavity and lung. Recent results link high ERBB3 activity with escape from therapy targeting other ERBBs in lung and breast cancers. Thus a wide and centrally important role for ERBB3 in cancer is becoming increasingly apparent. Several approaches for targeting ERBB3 in cancers have been tested or proposed. Small inhibitory RNA (siRNA) to ERBB3 or AKT is showing promise as a therapeutic approach to treatment of lung adenocarcinoma.

A novel Hsp90 inhibitor to disrupt Hsp90/Cdc37 complex against pancreatic cancer cells

Pancreatic cancer is an aggressive disease with multiple biochemical and genetic alterations. Thus, a single agent to hit one molecular target may not be sufficient to treat this disease. The purpose of this study is to identify a novel Hsp90 inhibitor to disrupt protein-protein interactions of Hsp90 and its cochaperones for down-regulating many oncogenes simultaneously against pancreatic cancer cells. Here, we reported that celastrol disrupted Hsp90-Cdc37 interaction in the superchaperone complex to exhibit antitumor activity in vitro and in vivo. Molecular docking and molecular dynamic simulations showed that celastrol blocked the critical interaction of Glu33 (Hsp90) and Arg167 (Cdc37). Immunoprecipitation confirmed that celastrol (10 micromol/L) disrupted the Hsp90-Cdc37 interaction in the pancreatic cancer cell line Panc-1. In contrast to classic Hsp90 inhibitor (geldanamycin), celastrol (0.1-100 micromol/L) did not interfere with ATP binding to Hsp90. However, celastrol (1-5 micromol/L) induced Hsp90 client protein degradation (Cdk4 and Akt) by 70% to 80% and increased Hsp70 expression by 12-fold. Celastrol induced apoptosis in vitro and significantly inhibited tumor growth in Panc-1 xenografts. Moreover, celastrol (3 mg/kg) effectively suppressed tumor metastasis by more than 80% in RIP1-Tag2 transgenic mouse model with pancreatic islet cell carcinogenesis. The data suggest that celastrol is a novel Hsp90 inhibitor to disrupt Hsp90-Cdc37 interaction against pancreatic cancer cells.

Targeted therapies for pancreatic cancer

INTRODUCTION

Pancreatic cancer is a devastating malignancy and a leading cause of cancer mortality. Furthermore, early diagnosis represents a serious hurdle for clinicians, as symptoms are non-specific and usually manifest in advanced, treatment-resistant stages of the disease.

SOURCES OF DATA

Here, we review the rationale and progress of targeted therapies currently under investigation.

AREAS OF AGREEMENT

At present, chemoradiation regimes are administered palliatively, and produce only marginal survival benefits, underscoring a desperate need for more effective treatment modalities.

AREAS OF CONTROVERSY

Questions have been raised as to whether erlotinib, the only targeted therapy to attain a statistically significant increase in median survival, is cost-effective.

GROWING POINTS

The last decade of research has provided us with a wealth of information regarding the molecular nature of pancreatic cancer, leading to the identification of signalling pathways and their respective components which are critical for the maintenance of the malignant phenotype.

AREAS TIMELY FOR DEVELOPING RESEARCH

These proteins thus represent ideal targets for novel molecular therapies which embody an urgently needed novel treatment strategy.

Novel therapies for pancreatic adenocarcinoma

Despite advances in our understanding of the molecular and genetic basis of pancreatic cancer, the disease remains a clinical challenge. Gemcitabine, the standard chemotherapy for pancreatic cancer, offers modest improvement of tumor-related symptoms and marginal advantage of survival. New approaches, alone and in combination with gemcitabine, are being developed to combat this cancer. In this article we review the current status of investigations into several classes of agents: matrix metalloproteinase inhibitors; farnesyl transferase inhibitors; epidermal growth factor receptor inhibitors, including monoclonal antibodies and tyrosine kinase inhibitors; cyclooxygenase-2 inhibitors, and others. The scientific rationale, mechanism of action, and clinical trial data for these novel agents are discussed.

Genetic alterations in pancreatic cancer

The diagnosis of pancreatic cancer is devastating for patients and their relatives as the incidence rate is approximately the same as mortality rate. Only a small percentage, which ranges from 0.4% to 4% of patients who have been given this diagnosis, will be alive at five years. At the time of diagnosis, 80% of pancreatic cancer patients have unresectable or metastatic disease. Moreover, the therapeutic alternatives offered by chemotherapy or radiotherapy are few, if not zero. For all these reasons, there is an imperative need of analyzing and understanding the primitive lesions that lead to invasive pancreatic adenocarcinoma. Molecular pathology of these lesions is the key of our understanding of the mechanisms underlying the development of this cancer and will probably help us in earlier diagnosis and better therapeutic results. This review focuses on medical research on pancreatic cancer models and the underlying genetic alterations.

Long-term immunity elicited by antibody-cytokine fusion proteins protects against sequential challenge with murine mammary and colon malignancies

We have previously reported that the antibody fusion proteins anti-HER2/neu IgG3 fused to IL-12 [(IL-12)-IgG3] or GM-CSF [IgG3-(GM-CSF)] independently or in combination are effective anti-tumor agents against D2F2/E2 murine mammary cancer cells expressing human HER2/neu in the peritoneum. Importantly, the long-term survivors were immune to the subcutaneous challenge with D2F2/E2 and the parental D2F2 not expressing HER2/neu. We now show that these long-term survivors also exhibit significant protection against subsequent subcutaneous challenge with the murine colon carcinoma CT26-HER2/neu, and later against subcutaneous challenge with the parental CT26. These results suggest that the long-term systemic protection against mammary cancer elicited by treatment with antibody-cytokine fusion proteins can be extended to prevent the growth of a tumor from different origin expressing HER2/neu, and that this protection is not limited to this antigen alone, since it also prevented the growth of the parental tumor cells.

Future strategies for targeted therapies and tailored patient management in pancreatic cancer

Pancreatic cancer represents the fourth leading cause of cancer-related mortality in the United States. The vast majority of patients are diagnosed at advanced stages of the disease, at which time gemcitabine-based chemotherapy is typically offered as the standard of care. However, as investigators have arrived at a greater understanding of pancreatic tumor biology, newer therapeutic agents that "target" specific pathways or molecules governing the growth, spread, and maintenance of tumor cells have gained considerable interest. Erlotinib, an orally bioavailable small molecule inhibitor of the epidermal growth factor receptor, is the first of these targeted compounds to be approved for use in combination with gemcitabine for patients with advanced pancreatic cancer. Other targeted agents, including monoclonal antibodies and small molecule inhibitors aimed at a variety of targets, also have been extensively evaluated, with limited success to date. A newer strategy worth pursuing involves tailoring an individual patient's therapy according to the molecular characteristics of both host and tumor, as has shown promise in other solid tumor types.

Emerging drugs for the treatment of pancreatic cancer

Treatment of pancreatic cancer remains challenging today and mostly palliative. Despite many efforts to understand the underlying mechanisms of this aggressive tumoral phenotype and to develop new therapeutic agents, advances in its management and survival benefit are poor. Although gemcitabine remains the backbone of routine therapy in advanced disease, newer drugs, mainly constituted by (multi)targeted agents, represent promising therapeutic areas. In this setting, anti-EGF receptor, antiangiogenic or both therapies combined appear to have valuable potential, providing their optimal and comprehensive development and use in pancreatic cancer. Multitargeted agents, such as receptor tyrosine kinase inhibitor small molecules, combining different therapeutic interventions, also deserve new preclinical and clinical development, supported and paralleled by a translational approach. Over the next few years, we need to identify new target mechanisms in pancreatic carcinogenesis, to rapidly test selected drugs against these targets and imperatively to understand and determine which patients respond and who will benefit from such therapies. Significant advances should be immediately evaluated in the perioperative setting in order to improve the curative approach of this devastating disease.

Her signaling in pancreatic cancer

Pancreatic cancer remains a treatment-refractory cancer. Standard therapy for metastatic cancer is gemcitabine chemotherapy, with a median survival of 5-6 months. The epidermal growth factor receptor (EGFR) is commonly expressed in pancreatic cancer and has been evaluated as a therapeutic target. A Phase III trial of gemcitabine with or without the EGFR inhibitor, erlotinib, demonstrated a modest but significant prolongation of survival with the addition of erlotinib. A Phase II trial of gemcitabine with the anti-EGFR antibody cetuximab resulted in a 1-year survival of 32%. A Phase III trial of gemcitabine with or without cetuximab and a randomized Phase II trial of the Murren regimen with or without cetuximab are completed; results for both are anticipated in 2007. A Phase I trial of gemcitabine with the EGFR/Her-2 inhibitor, lapatinib, is completed. Improved patient selection and rational combination of targeted therapies will be necessary to optimize the management of patients with this tragic disease.

Multimodality therapy for pancreatic cancer

Neoadjuvant chemoradiotherapy can be administered safely to patients with pancreatic cancer. Complete pathologic responses are rare, however, and the benefits of this approach compared with standard adjuvant therapy are uncertain. The only way to evaluate the efficacy of neoadjuvant chemoradiotherapy is a prospective trial involving a uniform patient population comparing the results of neoadjuvant and adjuvant therapy and a cohort receiving surgery alone. Such a study can be designed in an ethically sound manner but requires the collaboration of numerous institutions and careful coordination to achieve statistically conclusive results. The future of pancreatic cancer research rests on the availability and rapid transfer of new therapies from the laboratory to clinical research.

Novel therapeutic approaches in the treatment of advanced pancreatic carcinoma

Pancreatic cancer is still a malignant disease of grim prognosis despite all therapeutic efforts. Because clinical symptoms in the early stage are usually absent or aspecific, it is frequently discovered at advanced or metastatic stage, only around 15-20% of tumors are resectable. In the majority of patients only the chemotherapy offers a prolongation of life, but even the first-line chemotherapeutic agent, the gemcitabine has a modest survival benefit, and objective tumor response is rarely achieved. Combination of various cytostatics did not produce a significant improvement either. For that reason, continuous search for other agents is mandatory. Nowadays, in the era of molecular-targeted oncotherapeutic approaches, pancreatic cancer is also a subject such trials: epidermal growth factor receptor blockade, inhibition of angiogenesis, modulation of tumor response through the extracellular matrix, inhibition of cyclooxygenase-2, farnesyl transferase inhibitors, signal transduction inhibitors, ablation of the hormonal influence and some other aspects have all been studies, but to date, no breakthrough in the treatment of pancreatic carcinoma is proven. In several Phase II-III studies these compounds given alone displayed marginal effects, but when combined with the standard cytostatics, some beneficial effects were observed, however, some of them displayed a severe (sometimes fatal) toxicity. To date, the role of the molecular targeted therapy in pancreatic carcinoma is promising, but the results are not convincingly superior to the standard chemotherapeutic treatments. Pancreatic adenocarcinoma remains a great challenge for the oncologists, and continuous search for better molecules and/or combinations is inevitable.

HER family inhibitors in pancreatic cancer: current status and future directions

Pancreatic cancer is characterized by multiple genetic abnormalities that can be used as targets for specific therapeutics. The HER family consists of four transmembrane growth factor receptors. Targeting HER1 with the epidermal growth factor receptor tyrosine kinase inhibitor erlotinib demonstrated a survival advantage for patients with advanced pancreatic cancer. Multiple other agents that target members of the HER family are under investigation. These include reversible and irreversible, single and pan HER tyrosine kinase inhibitors. Chimeric, humanized and fully human monoclonal antibodies that target specific HER receptors are also being studied. These agents are also radiation sensitizers. This article reviews clinical trials of HER family inhibitors in pancreatic cancer, discusses the role of these agents in the management of patients and outlines future directions for pancreatic cancer management.

Antitumor effect of trastuzumab for pancreatic cancer with high HER-2 expression and enhancement of effect by combined therapy with gemcitabine

PURPOSE

The purpose of the present study was to evaluate whether trastuzumab has antitumor effect against pancreatic cancer and whether this effect is concordant with levels of HER-2, which is reportedly overexpressed in pancreatic cancer. We also investigated whether the effect is potentiated in combined therapy with gemcitabine.

EXPERIMENTAL DESIGN

Using immunohistochemistry and FACScan, we analyzed HER-2 expression in 16 pancreatic cancer cell lines. The in vitro antiproliferative effect of trastuzumab, alone and in combination with gemcitabine, was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The in vitro antibody-dependent cell-mediated cytotoxicity of trastuzumab was investigated by (51)Cr release assay. The in vivo antitumor effect of trastuzumab, alone and in combination with gemcitabine, was evaluated in nude mouse xenograft growth. The survival benefit was evaluated in a Capan-1 orthotopic implanted nude mouse model.

RESULTS

HER-2 expression of 2+ or more was observed in 10 and of 3+ in 2 of the 16 cell lines. No in vitro growth-inhibitory effect of trastuzumab was found in any cell line, but trastuzumab induced antibody-dependent cell-mediated cytotoxicity in proportion to HER-2 expression level. Trastuzumab inhibited tumor growth in Capan-1 (HER-2: 3+) xenografts and prolonged survival in the orthotopic model. These effects were increased by combined therapy with gemcitabine. In contrast, trastuzumab exhibited no antitumor effect against PANC-1 (HER-2: 1+) or SW1990 (HER-2: 2+) xenografts.

CONCLUSIONS

The antitumor effect of trastuzumab in pancreatic cancer with high HER-2 expression was shown in vitro and in vivo. Clinical application of trastuzumab is expected in pancreatic cancer with 3+ HER-2 expression.

Molecular prognostic factors in adenocarcinoma of the esophagus and gastroesophageal junction

OBJECTIVE

This review describes genetic and molecular changes related to adenocarcinoma of the esophagus and gastroesophageal junction (GEJ) with emphasis on prognostic value and possibilities for targeted therapy in clinical setting. Adenocarcinoma of the esophagus or GEJ is an aggressive disease with early lymphatic and hematogenous dissemination. Molecular pathology has revealed many molecular mechanisms of disease progression, which are related to prognosis. Some of these factors can be seen as prognostic factors per se. Better knowledge of molecular bases may lead to new paradigms, improved prognostication, early diagnosis and individually tailored therapeutic options.

METHODS

A review of recent English literature (1990-October 2005) concerning esophageal adenocarcinoma was performed. This review focuses on genetic and molecular changes as prognosticators of adenocarcinoma of the esophagus and GEJ.

RESULTS

A bewildering number of biomarkers have been described. Many genes and molecules have prognostic impact (cyclin D1, EGFR, Her-2/Neu, APC, TGF-beta, Endoglin, CTGF, P53, Bcl-2, NF-kappaB, Cox-2, E-cadherin, beta-catenin, uPA, MMP-1,3,7,9, TIMP, T( h )1/T( h )2 balance, CRP, PTHrP).

CONCLUSIONS

Adenocarcinomas of the esophagus and GEJ show multiple genetic alterations, which indicate that progression of cancer is a multistep complex process with many different alterations. Presumably, it is not one molecular factor that can predict the biological behavior of this cancer. The combination of diverse genetic alterations may better predict prognosis. In future, gene expression analysis with microarrays may reveal important prognostic information and the discovery of new genes and molecules associated with tumor progression and dissemination will enhance prognostication and offers adjuvant therapeutic options.

Phase I/II study of trastuzumab, paclitaxel, cisplatin and radiation for locally advanced, HER2 overexpressing, esophageal adenocarcinoma

PURPOSE

To determine the overall survival for patients with locally advanced, HER2 overexpressing, esophageal adenocarcinoma receiving trastuzumab, paclitaxel, cisplatin, and radiation on a Phase I-II study.

METHODS AND MATERIALS

Patients with adenocarcinoma of the esophagus without distant organ metastases and 2+/3+ HER2 overexpression by immunohistochemistry (IHC) were eligible. All patients received cisplatin 25 mg/m2 and paclitaxel 50 mg/m2 weekly for 6 weeks with radiation therapy (RT) 50.4 Gy. Patients received trastuzumab at dose levels of 1, 1.5, or 2 mg/kg weekly for 5 weeks after an initial bolus of 2, 3, or 4 mg/kg.

RESULTS

Nineteen patients were entered: 7 (37%) had celiac adenopathy, and 7 (37%) had retroperitoneal, portal adenopathy, or scalene adenopathy. Fourteen of 19 patients (74%) had either 3+ HER2 expression by immunohistochemistry, or an increase in HER2 gene copy number by HER2 gene amplification or high polysomy by fluorescence in situ hybridization. The median survival of all patients was 24 months and the 2-year survival was 50%.

CONCLUSIONS

Assessment of the effect of trastuzumab in the treatment of patients with esophageal adenocarcinoma overexpressing HER2 is limited by the small number of patients in this study. Overall survival, however, was similar to prior studies without an increase in toxicity. Evaluation of HER2 status should be performed in future trials for patients with adenocarcinoma of the esophagus that investigate therapies targeting the HER family.

Pharmacogenetics of anticancer drug sensitivity in pancreatic cancer

Chemotherapy has produced unsatisfactory results in pancreas cancer and novel approaches, including treatment tailoring by pharmacogenetic analysis and new molecular-targeted drugs, are required. The scarcity of effective therapies may reflect the lack of knowledge about the influence of tumor-related molecular abnormalities on responsiveness to drugs. Advances in the understanding of pancreas cancer biology have been made over the past decade, including the discovery of critical mutations in oncogenes (i.e., K-Ras) as well as the loss of tumor suppressor genes, such as TP53 and p16(INK4). Other studies showed the dysregulation of the expression of proteins involved in the control of cell cycle, proliferation, apoptosis, and invasiveness, such as Bcl-2, Akt, mdm2, and epidermal growth factor receptor. These characteristics might contribute to the aggressive behavior of pancreatic cancer and influence response to treatment. Indeed, the inactivation of p53 may explain the relative resistance to 5-fluorouracil, whereas Bcl-2 overexpression is associated with reduced sensitivity to gemcitabine. However, the future challenge of pancreas cancer chemotherapy relies on the identification of molecular markers that help in the selection of drugs best suited to the individual patient. Recent pharmacogenetic studies focused on genes encoding proteins directly involved in drug activity, showing the role of thymidylate synthase and human equilibrative nucleoside transporter-1 as prognostic factor in 5-fluorouracil- and gemcitabine-treated patients, respectively. Finally, inhibitors of signal transduction and angiogenesis are under extensive investigation, and several prospective trials have been devoted to this area. Pharmacogenetics is likely to play a central role in the personalization of treatment, to stratify patients based on their likelihood of response to both standard agents (i.e., gemcitabine/nucleoside transporters) and targeted treatments (i.e., epidermal growth factor receptor gene mutations and/or amplification and tyrosine kinase inhibitors), Thus, molecular analysis should be implemented in the optimal management of the patient affected by pancreatic adenocarcinoma.

Specific peptide ligand for Grb7 signal transduction protein and pancreatic cancer metastasis

BACKGROUND

Pancreatic cancer is one of the most aggressive malignancies, with high rates of invasion and metastasis and with generally poor prognosis. We previously found that metastasis was strongly associated with the expression of growth factor receptor-bound protein 7 (Grb7), which contains a Src homology 2 (SH2) domain. In this study, we evaluated Grb7 protein as a molecular target of therapy for metastatic pancreatic cancer.

METHODS

Grb7 protein expression was measured by immunohistochemistry in 36 human pancreatic cancer specimens and adjacent normal pancreatic tissue. We synthesized a nonphosphorylated peptide inhibitor that binds specifically to the SH2 domain of Grb7. Intracellular signaling was assessed by immunoprecipitation and immunoblot assays in cultured human pancreatic cancer cells. Cell migration was measured with a modified Boyden chamber method. Peritoneal metastasis of the pancreatic cancer cells was measured with a mouse model. All statistical tests were two-sided.

RESULTS

We found that 22 (61%) of 36 pancreatic cancer specimens had higher levels of Grb7 protein than their corresponding normal pancreatic tissue specimens. Grb7 expression was statistically significantly different between specimens from patients without lymph node metastasis (stage N0; two of the 10 patients) and patients with lymph node metastasis (stages N1 + N2; 20 of the 26 patients) (P = .006). The Grb7 peptide inhibitor selectively blocked the interaction between Grb7 and focal adhesion kinase and blocked the phosphorylation of Grb7 protein. In vivo Grb7 peptide inhibitor statistically significantly attenuated cell migration (for control peptide, 87.5 cells migrated, 95% confidence interval [CI] = 82.6 to 92.4 cells; for Grb7 peptide, 5.7 cells migrated, 95% CI = 2.3 to 9.0 cells; P < .001) and peritoneal metastasis of the pancreatic cancer cells in a mouse model, as assessed by the number of nodules (control = 72.6 nodules, 95% CI = 55.8 to 89.4 nodules; and for Grb7 peptide = 3.2 nodules, 95% CI = 1.6 to 4.8 nodules; P < .001, t test) and their weight (control = 4.13 g, 95% CI = 3.40 to 4.86 g; Grb7 peptide = 0.19 g, 95% CI = 0.06 to 0.32 g; P < .001, t test).

CONCLUSIONS

The Grb7 peptide inhibitor appears to be a promising molecularly targeted therapeutic agent against metastatic pancreatic cancer.

Expression and differential signaling of heregulins in pancreatic cancer cells

The EGF family of ligands and receptors plays an important role in the pathogenesis of pancreatic ductal adenocarcinoma (PDAC) and contributes to its aggressiveness. A number of molecular approaches have been developed to block these pathways, and studies have already proven the clinical benefit of this concept in PDAC. In the present study, we sought to determine the potential role of heregulins (HRGs), a family of EGF-like growth factors, in PDAC. Quantitative RT-PCR analysis revealed that HRGs as well as its signaling ErbB receptors were present in 4 of 4 human pancreatic cancer cell lines (PCCL). HRG-beta1 stimulated the growth of 3 of 4 PCCL, whereas HRG-alpha1 inhibited cell growth in 3 of 4 cell lines. Responses towards HRGs could in part be predicted by ErbB2 and ErbB3 expression levels. HRGs induced phosphorylation of different ErbB receptors as well as activation of MAPK, p38MAPK, JNK and PI3K in a cell- and ligand-specific manner. In vivo, HRG was upregulated in pancreatic cancer tissues and localized predominantly in the cancer cells. High HRG-beta levels but not HRG-alpha levels were associated with decreased patient survival. In conclusion, HRG is expressed by pancreatic cancer cells and influences pancreatic cancer cell growth and patient survival.

Novel therapies for pancreatic adenocarcinoma

Despite advances in our understanding of the molecular and genetic basis of pancreatic cancer, the disease remains a clinical challenge. Gemcitabine, the standard chemotherapy for pancreatic cancer, offers modest improvement of tumor-related symptoms and marginal advantage of survival. New approaches, alone and in combination with gemcitabine, are being developed to combat this cancer. In this article we review the current status of investigations into several classes of agents: matrix metalloproteinase inhibitors; farnesyl transferase inhibitors; epidermal growth factor receptor inhibitors, including monoclonal antibodies and tyrosine kinase inhibitors; cyclooxygenase-2 inhibitors, and others. The scientific rationale, mechanism of action, and clinical trial data for these novel agents are discussed.

Drug development in pancreatic cancer: finally, biology begets therapy

Pancreatic cancer is rarely curable, and only 5% of patients achieve long-term survival. The vast majority of patients present with metastatic or unresectable disease. Standard chemotherapy with gemcitabine provides clinical benefit to only a small minority of patients. Thus, the development and investigation of new therapies is clearly needed. As knowledge of the underlying biology of pancreatic cancer has increased, targeted therapies based upon preclinical laboratory work have been developed, and are entering clinical trials. Some of these agents lack traditional dose-limiting toxicities (DLTs) at biologically active doses, and therefore clinical evaluation may not follow traditional guidelines for cytotoxic drug development. This article focuses on targeted therapies currently undergoing clinical evaluation in pancreatic cancer. Classes of therapeutics reviewed include those targeting tumor-microenvironment interactions (matrix metalloproteinase inhibitors, vascular endothelial growth-factor blockade), signal transduction (e.g., farnesyltransferase inhibitors), growth-factor receptors (epidermal growth-factor receptor blockade, Her-2/neu, gastrin), and vaccine approaches. Currently, there is a renewed optimism that the clinical application of biologic understanding will lead to an improved outcome for patients with pancreatic cancer.