Metastatic Neuroendocrine Cancer Research Articles

Surgical Management and Emerging Therapies to Prolong Survival in Metastatic Neuroendocrine Cancer

Surgical Management and Emerging Therapies to Prolong Survival in Metastatic Neuroendocrine Cancer

Surgical Management and Emerging Therapies to Prolong Survival in Metastatic Neuroendocrine Cancer

Surgical Management and Emerging Therapies to Prolong Survival in Metastatic Neuroendocrine Cancer

Matrix Metalloproteinases Contribute Distinct Roles in Neuroendocrine Prostate Carcinogenesis, Metastasis, and Angiogenesis Progression

Prostate cancer is the leading form of cancer in men. Prostate tumors often contain neuroendocrine differentiation, which correlates with androgen-independent progression and poor prognosis. Matrix metalloproteinases (MMP), a family of enzymes that remodel the microenvironment, are associated with tumorigenesis and metastasis. To evaluate MMPs during metastatic prostatic neuroendocrine cancer development, we used transgenic mice expressing SV40 large T antigen in their prostatic neuroendocrine cells, under the control of transcriptional regulatory elements from the mouse cryptdin-2 gene (CR2-TAg). These mice have a stereotypical pattern of tumorigenesis and metastasis. MMP-2, MMP-7, and MMP-9 activities increased concurrently with the transition to invasive metastatic carcinoma, but they were expressed in different prostatic cell types: stromal, luminal epithelium, and macrophages, respectively. CR2-TAg mice treated with AG3340/Prinomastat, an MMP inhibitor that blocks activity of MMP-2, MMP-9, MMP-13, and MMP-14, had reduced tumor burden. CR2-TAg animals were crossed to mice homozygous for null alleles of MMP-2, MMP-7, or MMP-9 genes. At 24 weeks CR2-TAg; MMP-2(-/-) mice showed reduced tumor burden, prolonged survival, decreased lung metastasis, and decreased blood vessel density, whereas deficiencies in MMP-7 or MMP-9 did not influence tumor growth or survival. Mice deficient for MMP-7 had reduced endothelial area coverage and decreased vessel size, and mice lacking MMP-9 had increased numbers of invasive foci and increased perivascular invasion, as well as decreased tumor blood vessel size. Together, these results suggest distinct contributions by MMPs to the progression of aggressive prostate tumor and to helping tumors cleverly find alternative routes to malignant progression.

Seneca Valley Virus, a Systemically Deliverable Oncolytic Picornavirus, and the Treatment of Neuroendocrine Cancers

BackgroundNumerous clinical trials have demonstrated that oncolytic viruses can elicit antitumor responses when they are administered directly into localized cancers. However, the treatment of metastatic disease with oncolytic viruses has been challenging due to the inactivation of viruses by components of human blood and/or to inadequate tumor selectivity.MethodsWe determined the cytolytic potential and selectivity of Seneca Valley Virus-001 (SVV-001), a newly discovered native picornavirus, in neuroendocrine and pediatric tumor cell lines and normal cells. Suitability of the virus for intravenous delivery in humans was assessed by blood inactivation assays. Safety was evaluated in vivo using an immune-competent mouse model, and efficacy was evaluated in vivo in athymic mice bearing tumors derived from human small-cell lung cancer and retinoblastoma cell lines.ResultsCell lines derived from small-cell lung cancers and solid pediatric cancers were at least 10000-fold more sensitive to the cytolytic activity of SVV-001 than were any of the adult normal human cells tested. Viral infectivity was not inhibited by human blood components. Intravenous doses up to 1 × 1014 virus particles (vp) per kg were well tolerated, and no dose-limiting toxicity was observed in immune-competent mice. A single intravenous dose of 1 × 108 vp per kg into athymic mice bearing preestablished small-cell lung or retinoblastoma tumors resulted in complete, durable responses in ten of ten and five of eight mice, respectively.ConclusionsSVV-001 has potent cytolytic activity and high selectivity for tumor cell lines having neuroendocrine properties versus adult normal cells. Systemically administered SVV-001 has potential for the treatment of metastatic neuroendocrine cancers.

An open-label phase II clinical trial of PTK787 in patients with progressive neuroendocrine cancer

14127 Background: PTK787 is an orally active angiogenesis inhibitor blocking all known vascular endothelial growth factor receptors (VEGFR) and platelet-derived growth factor receptor (PDGFR)-tyrosine kinases . The majority of metastatic neuroendocrine malignancies express VEGF and PDGF receptors. Since both growth factors have been implicated in tumor-induced angiogenesis, PTK787 offers a novel approach for inhibiting tumor growth. Methods: In a phase II trial, we investigated the safety and antitumor activity of PTK787 in patients who had biopsy-proven metastatic neuroendocrine cancer, such as carcinoid, and had shown evidence of progression on somatostatin analog therapy. Eligible patients had measurable lesions other than bone, a Karnofsky performance status > 60% and normal hematologic, renal and hepatic functions. Patients on octreotide therapy were required to be on a stable dose not exceeding 30 mg monthly of the LAR formulation. Initial dosing of PTK787 was 1,250 mg daily. Results: Eight patients (5 males) were enrolled between 5/20/05 to 9/09/06. Median age was 61 years (range, 48 to 65). There was 1 withdrawal of consent. The median time on study was 6.2 ± 2.1 mos with 1 patient continuing on treatment as of January 2007. Three patients required a 10–28 day discontinuation for rising SGOT/SGPT, alkaline phosphatase and Grade2 proteinuria. Resumption of PTK787 at 1,000 mg daily was well tolerated in 1 patient. One patient developed carcinoid crises with fever, flushing, rising 5-HIAA accompanied by Grade 2 proteinuria. A partial (>50% decrease in 5-HIAA) biochemical response was observed in 25% of the patients. The observed radiographic (CT scans) and scintigraphic (OctreoScan) responses in 6 patients has been stable disease at 3 and 6 mos. Recruitment to this trial continues. Conclusions: PTK787 results in a 25% biochemical partial response rate in neuroendocrine tumor patients with progressive disease following somatostatin analog therapy. Alternative dosing schedules are planned to improve tolerability. [Table: see text]

Perioperative outcome after laparoscopic radiofrequency ablation of liver tumors: an analysis of 521 cases

Radiofrequency thermal ablation (RFA) is gaining increased acceptance for the treatment of unresectable primary and metastatic liver tumors. Understanding the morbidity and laboratory changes after RFA is important for operative indications and perioperative management. The authors prospectively analyzed the 30-day morbidity and mortality rates of patients undergoing laparoscopic RFA for liver tumors in a 10-year period. Laboratory studies included a complete blood count, electrolytes, liver function tests, prothrombin time/international normalized ratio (INR), and tumor markers obtained preoperatively, on postoperative days (PODs) 1 and 7, then at 3 months. A total of 521 RFA procedures were performed for 428 patients (286 men and 142 women) with a mean age of 61 years (range, 25-89 years). A total of 346 patients underwent a single operation, and 82 patients had two or more operations. The pathology was metastatic colon cancer for 244 patients (47%), hepatocellular cancer for 109 patients (21%), metastatic neuroendocrine cancer for 74 patients (14%), and other noncolorectal, nonneuroendocrine liver metastasis for 94 patients (18%). A total of 1,636 lesions (mean, 3.1 per patient; range, 1-16) were ablated. The mean tumor size was 2.7 +/- 1.6 cm (range, 0.3-11.5 cm). All cases were managed laparoscopically. The 30-day mortality rate was 0.4% (n = 2), and the morbidity rate was 3.8 % (n = 20). The average length of hospital stay was 1 day for RFA-only cases and 2.1 days when another surgical procedure was combined with RFA. Serum aspartate aminotransferase (AST) increased 14-fold, alanine aminotransferase (ALT) increased 10-fold, and bilirubin levels increased 2-fold on POD 1, with return to baseline in 3 months. Serum alkaline phosphatase and gamma-glutamyltransferase (GGT) levels showed a 25% increase on POD 7, with return to baseline in 3 months. There were no significant changes in platelet counts or prothrombin times postoperatively. This large series provides valuable insight into the perioperative period and allows the expected morbidity of the procedure to be understood. Despite significant patient comorbidities, this procedure was tolerated with low morbidity and mortality rates. Postoperative coagulopathy was not observed. A postoperative rise in liver function tests is expected, reflecting the liver injury response to RFA. This information can be used to expand the patient population that may benefit from laparoscopic RFA.

Linkage between cellular communications, energy utilization, and proliferation in metastatic neuroendocrine cancers

To identify metabolic features that support the aggressive behavior of human neuroendocrine (NE) cancers, we examined metastatic prostate NE tumors and derived prostate NE cancer (PNEC) cell lines from a transgenic mouse model using a combination of magic angle spinning NMR spectroscopy, in silico predictions of biotransformations that observed metabolites may undergo, biochemical tests of these predictions, and electrophysiological/calcium imaging studies. Malignant NE cells undergo excitation and increased proliferation when their GABA(A), glutamate, and/or glycine receptors are stimulated, use glutamate and GABA as substrates for NADH biosynthesis, and produce propylene glycol, a precursor of pyruvate derived from glycine that increases levels of circulating free fatty acids through extra-NE cell effects. Treatment of nude mice containing PNEC tumor xenografts with (i) amiloride, a diuretic that inhibits Abp1, an enzyme involved in NE cell GABA metabolism, (ii) carbidopa, an inhibitor of dopa decarboxylase which functions upstream of Abp1, plus (iii) flumazenil, a benzodiazepine antagonist that binds to GABA(A) receptors, leads to significant reductions in tumor growth. These findings may be generally applicable: GeneChip data sets from 471 human neoplasms revealed that components of GABA metabolic pathways, including ABP1, exhibit statistically significant increases in their expression in NE and non-NE cancers.

An open-label phase II study evaluating the safety and efficacy of PTK787 in patients with progressive metastatic neuroendocrine cancer

14124 Background: PTK787, an aminophthalazine, is an orally active angiogenesis inhibitor blocking all known vascular endothelial growth factor receptors (VEGFR)- and platelet-derived growth factor receptor (PDGFR)-tyrosine kinases . The majority of metastatic neuroendocrine malignancies express VEGF and PDGF receptors. Since both growth factors have been implicated in tumor-induced angiogenesis, PTK787 offers a novel approach for inhibiting tumor growth. Methods: In a phase II trial, we investigated the safety and antitumor activity of PTK787 in patients who had biopsy-proven metastatic neuroendocrine cancer, such as carcinoid, and had shown evidence of progression on somatosatin analog therapy. Eligible patients had measurable lesions other than bone, a Karnofsky performance status >60 and normal hematologic, renal and hepatic functions. Patients on octreotide therapy were required to be on a stable dose not exceeding 30 mg monthly of the LAR formulation. Initial dosing of PTK787 was 1,250 mg daily. Results: Six patients (4 males) were enrolled between 5/20/05 to 8/09/05. Median age was 61 years (range, 48 to 65). There was 1 withdrawal of consent. The remaining 5 patients continue on treatment as of January 2006. One patient required a 10 day discontinuation for rising SGOT/SGPT and alkaline phosphatase. Resumption of PTK787 at 1,000 mg daily was well tolerated in this patient. Radiographically and scintigraphically, all 5 patients have demonstrated stable disease by CT and OctreoScan, respectively. Recruitment to this trial continues. Conclusions: PTK787 is generally well tolerated in patients with metastatic neuroendocrine cancer and may be effective in controlling somatostatin analog resistant disease though partial radiographic responses have not been observed. No significant financial relationships to disclose.

The Role of Cytoreductive Hepatic Surgery as an Adjunct to the Management of Metastatic Neuroendocrine Carcinomas

Patients with metastatic neuroendocrine cancers to the liver often present with disabling endocrinopathies and pain associated with bulky disease. Quality of life for these patients is poor and can require long-term therapy with somatostatin analogs for control of their symptoms. Alternative therapies to decrease tumor burden and subsequent hormone release have been investigated. Of these, cytoreductive surgery was found to have the most consistent and profound impact on symptom regression and overall survival. Several cases are reported that illustrate an aggressive multimodality approach in the treatment of metastatic neuroendocrine cancers to the liver. The literature is reviewed and the role of cytoreductive surgery in the management of hepatic neuroendocrine metastases is discussed. Cytoreductive surgery can be performed safely with minimal morbidity and mortality. Regression of symptoms occurs in the majority of patients and survival is prolonged. Surgical intervention as part of an aggressive multimodality treatment plan results in improved outcomes for patients with advanced hepatic metastases of neuroendocrine origin. Future directions may include earlier surgical intervention with adjuvant therapies reserved for aggressive recurrent disease.

Molecular Characterization of a Metastatic Neuroendocrine Cell Cancer Arising in the Prostates of Transgenic Mice

The features and functions of prostatic neuroendocrine (NE) cells remain ill-defined. Neuroendocrine differentiation (NED) in adenocarcinoma of the human prostate (CaP) is associated with more aggressive disease, but the underlying mediators are poorly understood. We examined these issues in transgenic mice that utilize regulatory elements from the cryptdin-2 gene (Defcr2) to express simian virus 40 large T antigen (TAg) in prostatic NE cells. CR2-TAg mice develop prostatic intraepithelial neoplasia at 8 weeks of age, 1 week after the onset of TAg expression. An invasive phase follows 2-4 weeks later, with lymph node, liver, lung, brain, and bone metastases appearing within 16 weeks. DNA microarray studies revealed 122 mRNAs that were increased >/=2-fold in duplicate assays of 16-week-old CR2-TAg versus normal prostates. Thirty two transcripts encode proteins associated with neurons and endocrine cells (e.g. basic helix loop helix, SRY-related high mobility group box and sine-oculis homeobox transcription factors, Hu RNA-binding proteins, neuronatin, Racgap1, collapsin response mediator protein-1, synaptotagmin-1, proprotein convertase, and secretogranins). Follow-up studies of candidate mediators and biomarkers of differentiation/growth in the microarray data set involved real time quantitative reverse transcriptase-PCR assays of laser capture microdissected NE cells from CR2-TAg prostates plus liver metastases, and immunohistochemical comparisons of transgenic mouse prostates and 35 human CaP samples. Our findings include (a) expression of the bHLH mouse achaete-scute homolog (mASH1) in normal and CR2-TAg NE cells and foci of NED in human CaP, (b) glutamic acid decarboxylase and its product (gamma-aminobutyric acid) in neoplastic NE cells juxtaposed next to cohorts of normal gamma-aminobutyric acid receptor expressing secretory cells (a potential route for paracrine interactions between these two epithelial lineages), and (c) aromatic l-amino-acid decarboxylase, but not its dopamine/serotonin products, in CR2-TAg NE cells and NED. These results underscore the value of CR2-TAg mice for characterizing normal NE cell biology and tumorigenesis.