CaSm/gemcitabine chemo-gene therapy leads to prolonged survival in a murine model of pancreatic cancer.

BACKGROUND: CaSm, the cancer-associated Sm-like oncogene, is overexpressed in greater than 80% of pancreatic tumors. We previously reported that an adenovirus expressing antisense RNA to CaSm (Ad-alpha CaSm) can decrease pancreatic tumor growth in vivo but is not curative. In the current study we investigated the mechanism of Ad-alpha CaSm's antitumor effect to rationally approach combinatorial therapy for improved efficacy. METHODS: AsPC-1 and Panc-1 human pancreatic cancer cells were treated with Ad-alpha CaSm and examined by MTT assay for in vitro proliferation changes. Flow cytometry determined the effect of CaSm down-regulation on the cell cycle, and then cells treated with Ad-alpha CaSm in combination with cisplatin, etoposide, or gemcitabine chemotherapies were reexamined by MTT assay. SCID-Bg mice bearing subcutaneous AsPC-1 tumors were treated with Ad-alpha CaSm, gemcitabine, or the combination and monitored for tumor growth and survival. RESULTS: Treatment with Ad-alpha CaSm reduced the proliferation of AsPC-1 and Panc-1 cells (59% and 44%, respectively; P <.05). The cell cycle revealed a cytostatic block with decreased G(1) phase and increased DNA content in treated cells. The combination of Ad-alpha CaSm with gemcitabine significantly reduced in vitro proliferation (66% vs 39% and 48% for controls), decreased in vivo AsPC-1 tumor growth by 71% (n = 10), and extended survival time from 57 to 100 days. CONCLUSIONS: Down-regulation of CaSm reduces the growth of pancreatic cancer cells by altering the cell cycle in a cytostatic manner. The combination of Ad-alpha CaSm with gemcitabine is more effective than either agent used separately.

The cancer-associated Sm-like oncogene: a novel target for the gene therapy of pancreatic cancer.

BACKGROUND: The prognosis for pancreatic cancer (PC) remains dismal, providing a clear need for the development of novel therapies. We have previously shown that the cancer-associated Sm-like (CaSm) oncogene is overexpressed in the great majority of pancreatic tumors and is required to maintain the transformed phenotype. The purpose of this study was to determine whether the application of CaSm antisense gene therapy would generate a significant antitumor effect against PC. METHODS: An adenoviral vector (Ad-alphaCaSm) expressing a 900-base pair antisense RNA to CaSm was created. The PC cell lines AsPC-1 and Capan-1 were infected with this vector and examined for changes in in vitro proliferation by using methyl thiazol tetrazolium and soft agar assays. SCID-Bg mice bearing subcutaneous AsPC-1 tumors were treated with Ad-alphaCaSm (1 x 10(9) plaque-forming units) as a single intratumor injection with tumor growth and survival monitored. RESULTS: AsPC-1 and Capan-1 cells showed decreased in vitro proliferation (93%, P =.0041, and 70%, P =. 0038, respectively) and anchorage independent growth (55%, P =.02, and 45%, P =.03, respectively) after treatment. Ad-alphaCaSm reduced in vivo AsPC-1 tumor growth by 40% (n = 10), extending median survival time from 35 to 60 days. CONCLUSIONS: Ad-alphaCaSm demonstrates a significant antitumor effect against pancreatic cancer both in vitro and in vivo. These results support the role of CaSm as a significant gene involved in the neoplastic transformation of pancreatic tumors. Thus CaSm represents a novel gene target in PC and holds potential as a new treatment approach either alone or in combination with existing therapies.

Primary T-cell and activated macrophage response associated with tumor protection using peptide/poly-N-acetyl glucosamine vaccination.

The mode of peptide-based cancer vaccine administration critically affects the ability to achieve a clinically relevant tumor-specific response. We have previously shown (Cole et al., Clin. Cancer Res., 3: 867-873, 1997) that a specific formulation of the polysaccharide poly-N-acetyl glucosamine (p-GlcNAc, designated as F2 gel) is an effective vehicle for sustained cytokine and peptide delivery in vitro. The purpose of this study was to evaluate the efficacy of F2 gel/peptide vaccination in the murine EG.7-OVA tumor model and to elucidate potential mechanisms involved in the observed cell-mediated response. C57BL/6 mice were given injections of 200 microl in the base of tail/footpad using either F2 gel alone or 200 microg of: SIINFEKL minimal peptide (OVA) in PBS, OVA peptide/endoplasmic reticulum insertion signal sequence fusion (ESOVA) in PBS, OVA in F2 gel, or ESOVA in F2 gel. Splenocytes were tested 10 days later for a secondary response using a Cr51 assay as well as a primary CTL response using the lactate dehydrogenase cytotoxicity assay. Splenocytes from immunized mice were harvested at specific time points and assayed for cell surface and intracellular markers. On day 10 postvaccination, animals were challenged with EG.7-OVA murine thymoma cells. Tumor size and appearance were recorded. Vaccination with F2 gel/peptide (either OVA or ESOVA) resulted in a primary T-cell response (up to 25% tumor cell-specific lysis) and no tumor growth in 69% of the mice. By 48 h, the proportion of splenic T cells had increased 4-fold compared with B cells. Presence of an increased Th1 CD4 helper population was demonstrated by IFN-gamma production. CD4 cells were activated at 24 and 48 h as shown by IL-2 receptor alpha chain expression (from 2% basal expression to 15.4% at 48 h). Activated splenic macrophages increased from 3 to 8% within 10 h, and their level of B7-2 expression doubled. Depletion of macrophages before vaccine injection abolished any tumor-specific primary CTL response. F2 gel/peptide tumor vaccine can prime the immune system in an antigen-specific manner by generating a measurable primary T-cell response with minimal peptide; this process involves macrophage presence and activation as well as induction of Th1 CD4 cells. This is the first demonstration of a primary CTL response generated with minimal peptide vaccination using a noninfectious delivery system. These results justify additional studies to better define the mechanisms involved in F2 gel/peptide vaccination in preparation for clinical trials.

Diminished venous vascular capacitance in patients with univentricular hearts after the Fontan operation.

Patients who have undergone Fontan's operation are known to have impaired cardiac output response to dynamic exercise. This may be due to either poor cardiac function or a limited ability to mobilize blood from capacitance vessels due to increased resting venous tone. We tested the latter hypothesis by determining venous vascular capacitance at rest and during orthostatic stress produced by lower body negative pressure (LBNP) in 6 subjects who had undergone the Fontan operation and 6 healthy age-, sex-, height-, and weight-matched controls. Resting blood volume was similar for Fontan and control subjects (79 +/- 6 vs 70 +/- 3 ml/kg body weight, respectively), while central venous pressure (CVP) was elevated in Fontan subjects (18.4 +/- 1.0 vs 3.5 +/- 0.9 mm Hg, p < 0.05). Forearm venous capacitance at a distending pressure of 40 mm Hg was less in Fontan subjects than in controls (2.6 +/- 0.1 vs 3.9 +/- 0.5 ml/100 ml), while resting plasma norepinephrine level was elevated in Fontan subjects (255 +/- 28 vs 144 +/- 9 pg/ml, p < 0.05). The increase in calf volume (1.6 +/- 0.2 vs 2.3 +/- 0.2 ml) and decrease in CVP (-5.0 +/- 0.5 vs -6.7 +/- 1.1 mm Hg) during -30 mm Hg LBNP were smaller for Fontan than control subjects (p < 0.05). Reduced forearm venous capacitance and diminished pooling of blood into capacitance vessels of the leg during orthostatic stress indicated higher venous tone in Fontan than control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Pansystolic murmur in the newborn: tricuspid regurgitation versus ventricular septal defect.

Neonates with a pansystolic murmur who had Doppler echocardiography were reviewed. Ten infants had tricuspid regurgitation (detected at a mean age of 25 hours), 12 had a ventricular septal defect (detected at 65 hours), and seven had both. Tricuspid regurgitation is the more likely cause of a pansystolic murmur at the lower left sternal border in the first day of life.

Carcinoma of the esophagus. An aggressive one-stage palliative approach.

We reviewed the records of 44 consecutive patients with advanced esophageal carcinoma treated at either a Veterans Administration or a city-country hospital. The patients, 38 men and six women, ranged in age from 27 to 72 years and had been referred for operative management. The average duration of dysphagia was 5 months. All patients underwent a one-stage esophagogastrectomy with esophagogastrostomy. The last 34 patients also had a modified fundoplication. Lesions at the gastroesophageal junction were approached via a low left thoracotomy and the others via a simultaneous right thoracotomy and laparotomy. All patients had preoperative enteral or parenteral hyperalimentation. Seven patients died within 30 days after operation (operative mortality 16%). Twenty-six patients lived from 3 to 28 months postoperatively (average 11.5 months). Eleven are alive at present (average 10 months). Postoperative complications were as follows: anastomotic leak, three patients (two died); respiratory failure, four (two died); stricture, three; myocardial infarction, two (two died); cholecystitis, one; and pulmonary embolus, one (patient died). Thirty-four patients had modified fundoplication, and an inconsequential anastomotic leak developed in one. In contrast, two of the 10 patients who did not have modified fundoplication died as a result of anastomotic leak. Preoperative hospital stay ranged from 10 to 28 days (average 18); postoperative stay ranged from 10 to 40 days (average 16). Except for the three patients in whom stricture developed, all patients (92%) had continuous relief of dysphagia. We conclude that one-stage esophagogastrectomy with esophagogastrostomy is applicable in most cases and is associated with both satisfactory long-term palliation and a reasonable period of hospitalization. The addition of a modified fundoplication results in a relatively low rate of anastomotic leak.