Liposomal doxorubicin plus radiofrequency ablation for complete necrosis of a hepatocellular carcinoma.

Radiofrequency ablation (rfa) is a standard treatment for small, unresectable hepatocellular carcinomas (hccs). However, rfa for larger tumours is less successful, and intravenous lyso-thermosensitive liposomal doxorubicin during rfa is one technique postulated to potentially address that limitation. This drug-plus-device combination therapy was used to completely treat a hcc in a patient who underwent liver transplantation 79 days later.

The tumour microenvironment: a novel target for cancer therapy.

Cancer therapy is in the midst of a major paradigm shift. Traditionally, cancer treatments have focused on tumour cells. However, studies over the past few decades have demonstrated that cancer is a vastly complex entity with multiple components affecting a tumour's growth, invasion and metastasis. These components, collectively termed the 'tumour microenvironment', include endothelial cells, pericytes, fibroblasts, inflammatory cells, leucocytes and elements of the extracellular matrix (ECM). Biological agents that target components of the tumour microenvironment may provide an interesting alternative to traditional tumour cell-directed therapy. Because of the complexity of the tumour milieu, the most beneficial therapy will likely involve the combination of one or more agents directed at this new target. This review highlights recent preclinical and clinical studies involving agents that target tumour vasculature, leucocytes, pericytes, cancer-associated fibroblasts and ECM components. We pay particular attention to combination therapies targeting multiple components of the tumour microenvironment, and aim to demonstrate that this strategy holds promise for the future of cancer treatment.

Effect of retroviral endostatin gene transfer on subcutaneous and intraperitoneal growth of murine tumors.

BACKGROUND: Inhibiting tumor angiogenesis is a promising new strategy for treating cancer. Difficulties with the stability, manufacture, and long-term administration of recombinant antiangiogenic proteins have prompted investigators to use gene therapy to generate these proteins in vivo. We investigated whether transfer of the gene encoding the angiogenesis inhibitor endostatin into the murine liver cell line NMuLi could inhibit tumor growth in vivo. METHODS: NMuLi cells were transduced with retroviral vectors containing the murine endostatin gene. The presence and function of endostatin in transduced cell supernatants were confirmed by competitive enzyme immunoassay and endothelial cell proliferation assays. Nude mice were given a subcutaneous or intraperitoneal injection with NMuLi cells, control transduced cells (NEF-null), or endostatin-transduced clones (NEF-Endo1 to 4) and were monitored for tumor growth. All statistical tests were two-sided. RESULTS: Supernatants from the clone secreting the lowest amount of endostatin (NEF-Endo4, 28 ng/mL) inhibited endothelial cell proliferation by 6% (95% confidence interval [CI] = 0% to 12%), and those from the clone secreting the highest amount (NEF-Endo1, 223 ng/mL) inhibited endothelial cell proliferation by 20% (95% CI = 13% to 27%). Increased levels of endostatin were detected in tumor lysates, but not serum, of mice given a subcutaneous injection of NEF-Endo1 cells. After 63 days, mice given a subcutaneous injection of parental NMuLi or NEF-null cells had tumor volumes of 2400 mm(3) (95% CI = 1478 mm(3) to 3300 mm(3)) and 2700 mm(3) (95% CI = 2241 mm(3) to 3144 mm(3)), respectively, compared with mean tumor volumes of less than 30 mm(3) in mice given an injection of NEF-Endo clones, a statistically significant difference (P<.001). After 123 days, all 16 mice given an intraperitoneal injection of parental NMuLi or NEF-null cells had died, compared with only three (9%) of 32 mice given an injection of NEF-Endo clones. CONCLUSIONS: Retroviral endostatin gene transfer leads to secretion of functional endostatin that is sufficiently active to inhibit tumor growth. Further studies of retroviral endostatin gene transfer for the treatment of cancer are warranted.

Antiangiogenic gene therapy of cancer utilizing a recombinant adenovirus to elevate systemic endostatin levels in mice.

Gene therapy represents a possible alternative to the chronic delivery of recombinant antiangiogenic proteins to cancer patients. Inducing normal host tissues to produce high circulating levels of these proteins may be more effective than targeting antiangiogenic genes to tumor tissue specifically. Previously reported gene therapy approaches in mice have achieved peak circulating endostatin levels of 8-33 ng/ml. Here we report plasma endostatin levels of 1770 ng/ml after administration of a recombinant adenovirus. Growth of MC38 adenocarcinoma, which is relatively resistant to adenoviral infection, was inhibited by 40%. These findings encourage gene delivery approaches that use the host as a "factory" to produce high circulating levels of antiangiogenic agents.

Sensitization of tumor necrosis factor alpha-resistant human melanoma by tumor-specific in vivo transfer of the gene encoding endothelial monocyte-activating polypeptide II using recombinant vaccinia virus.

Tumor necrosis factor alpha (TNF-alpha) is a proinflammatory cytokine with potent experimental antitumor activity. Its clinical use in cancer treatment is severely limited by its considerable toxicity after systemic administration, and it is currently confined to isolated limb and organ perfusion settings. In this report, we introduce a novel concept of TNF-alpha-based gene therapy using the TNF-sensitizing properties of endothelial cell monocyte-activating polypeptide II (EMAP-II). We hypothesized that transfer of the EMAP-II gene into established TNF-resistant human melanomas would render these tumors sensitive to subsequent systemic TNF-alpha treatment. To achieve tumor selective gene delivery, we constructed a recombinant vaccinia virus encoding the human EMAP-II gene (vvEMAP). In vitro transfection of human melanoma cells led to the production of EMAP-II by these cells. Supernatants of vvEMAP-transfected tumor cells mediated the induction of tissue factor in endothelial cells. We characterized the pattern of gene expression after systemic administration of a recombinant vaccinia virus encoding a reporter gene in a murine in vivo model of s.c. human melanoma. Gene expression in tumor tissue was increased 100-fold as compared with normal tissue, providing evidence for tumor-selective gene delivery. Finally, human melanomas in nude mice were sensitized in vivo by transferring the EMAP-II gene using vvEMAP. Subsequent systemic administration of TNF-alpha led to tumor regression and growth inhibition of these previously TNF-resistant tumors (P < 0.05). This approach using gene therapy to sensitize primarily unresponsive tumors toward TNF-alpha may enhance the usefulness of TNF-alpha in clinical treatment strategies by increasing the window for the therapeutic application of the cytokine, thus reducing the dose necessary for antitumor responses and subsequently reduce toxicity.

In vivo sensitivity of human melanoma to tumor necrosis factor (TNF)-alpha is determined by tumor production of the novel cytokine endothelial-monocyte activating polypeptide II (EMAPII).

Tumor necrosis factor (TNF)-alpha is a potent anticancer agent that seems to selectively target tumor-associated vasculature resulting in hemorrhagic necrosis of tumors without injury to surrounding tissues. The major limitation in the clinical use of TNF has been severe dose-limiting toxicity when administered systemically. However, when administered in isolated organ perfusion it results in regression of advanced bulky tumors. A better understanding of the mechanisms of TNF-induced antitumor effects may provide valuable information into how its clinical use in cancer treatment may be expanded. We describe here that the release of a novel tumor-derived cytokine endothelial-monocyte-activating polypeptide II (EMAPII) renders the tumor-associated vasculature sensitive to TNF. EMAPII has the unique ability to induce tissue factor production by tumor vascular endothelial cells that initiates thrombogenic cascades, which may play a role in determining tumor sensitivity to TNF. We demonstrate here that constitutive overexpression of EMAPII in a TNF-resistant human melanoma line by retroviral-mediated transfer of EMAPII cDNA renders the tumor sensitive to the effects of systemic TNF in vivo, but not in vitro. This interaction between tumors and their associated neovasculature provides an explanation for the focal effects of TNF on tumors and possibly for the variable sensitivity of tumors to bioactive agents.

Systemic cancer therapy with a tumor-selective vaccinia virus mutant lacking thymidine kinase and vaccinia growth factor genes.

We have demonstrated previously the oncolytic effects of a systemically delivered, replicating vaccinia virus. To enhance the tumor specificity of this vector, we have developed a combined thymidine kinase-deleted (TK-) and vaccinia growth factor-deleted (VGF-) vaccinia virus and investigated its properties in vitro and in vivo. The gene for enhanced green fluorescent protein (EGFP) was inserted into the TK locus of a VGF- vaccinia virus by homologous recombination creating a double-deleted mutant vaccinia virus (vvDD-GFP). Infection of resting and dividing NIH3T3 cells with vvDD-GFP yielded reduced viral recovery compared with wild-type (WT), TK-, or VGF- viruses from resting cultures but equivalent virus recovery from dividing cultures. Eight days after nude mice were injected i.p. with 10(7) plaque-forming units (pfu) of WT, TK-, VGF-, or vvDD-GFP vaccinia virus, tissues and tumor were harvested for viral titer determination. No virus was recovered from the brains of mice injected with vvDD-GFP compared with the other viruses, which ranged from 130 to 28,000 pfu/mg protein; however, equivalent amounts were recovered from tumor. There was no toxicity from vvDD-GFP because nude mice receiving 10(8) pfu of IP vvDD-GFP lived >100 days, whereas mice receiving WT, VGF-, or TK- virus had median survivals of only 6, 17, and 29 days, respectively. Similar results were seen when 10(9) pfu of vvDD-GFP were given. Nude mice bearing s.c. murine colon adenocarcinoma (MC38) had significant tumor regression after treatment with 10(9) pfu of systemic (i.p.) vvDD-GFP compared with control (mean tumor size, 180.71 +/- 35.26 mm(3) versus 2796.79 +/- 573.20 mm(3) 12 days after injection of virus). Our data demonstrate that a TK- and VGF- mutant vaccinia virus is significantly attenuated in resting cells in vitro and demonstrates tumor-specific replication in vivo. It is a promising vector for use in tumor-directed gene therapy, given its enhanced safety profile, tumor selectivity, and the oncolytic effects after systemic delivery.

Isolated hepatic perfusion with tumor necrosis factor and melphalan for unresectable cancers confined to the liver.

PURPOSE: To evaluate the efficacy and systemic and regional toxicities of hyperthermic isolated hepatic perfusion (IHP) using tumor necrosis factor (TNF) and melphalan for the treatment of unresectable primary or metastatic cancers confined to the liver. PATIENTS AND METHODS: Thirty-four patients (18 men and 16 women; mean age, 49 years) underwent a 60-minute hyperthermic (39.5 degrees to 40.0 degrees C) IHP performed by laparotomy that used TNF 1.0 mg and melphalan 1.5 mg/kg. Perfusion inflow was through the gastroduodenal artery and outflow was from a cannula positioned in an isolated segment of retrohepatic inferior vena cava (IVC). Infrahepatic IVC and portal venous blood flow were shunted to the axillary vein using an external venoveno bypass circuit. Complete vascular isolation of the liver was confirmed by an I-131-labelled human serum albumin monitoring technique. RESULTS: There was no operative mortality. Seventy-five percent of patients had reversible grade III or IV (National Cancer Institute Common Toxicity Criteria) hepatic toxicity with one treatment-related mortality (3%) because of hepatic venoocclusive disease. In 33 assessable patients, the overall response rate was 75% (complete response, one patient [3%]; partial response, 26 patients [72%]). With a median potential follow-up of 15 months, the mean duration of response was 9 months (range, 2 to 30 months). CONCLUSION: IHP with TNF and melphalan results in significant regression of bulky hepatic cancers confined to the liver in the majority of patients. Based on these initial results, further refinement of this treatment technique is warranted; perhaps by the combination of IHP with other regional treatment strategies to provide long-term control of unresectable cancers confined to liver.

Prognostic value of initial fasting serum gastrin levels in patients with Zollinger-Ellison syndrome.

PURPOSE: To assess the value of the initial fasting serum gastrin (FSG) at presentation in patients with Zollinger-Ellison Syndrome (ZES) in predicting primary tumor characteristics and survival. PATIENTS AND METHODS: A total of 239 patients were treated for ZES between December 1981 and September 1998, with a mean follow-up of 9.1 +/- 0.6 years. At initial evaluation, 86 patients (36%) had mild (0 to 499 pg/mL), 61 (25.5%) had moderate (500 to 1,000 pg/mL), and 92 (38.5%) had severe (> 1,000 pg/mL) elevations in FSG. Primary tumor location and size, presence of lymph node or hepatic metastases, and survival were analyzed based on the level of initial FSG. RESULTS: In patients with sporadic ZES, but not in those with multiple endocrine neoplasia type 1 (MEN-1) and ZES, there was a significant relationship between the level of initial FSG and tumor size and location of primary tumor, frequency of lymph node and liver metastases, and survival. The median 5- and 10-year survival decreased with increasing initial FSG (P <.001) in patients with sporadic ZES; MEN-1 patients lived longer than sporadic ZES patients (P =.012), and survival in this group was not associated with the level of initial FSG. Multivariate analysis showed that factors independently associated with death from disease in patients with sporadic ZES were liver metastases (P =.0001), a pancreatic site (P =.0027), and primary tumor size (P =.011) but not initial FSG (P >.30). CONCLUSION: The severity of FSG at presentation is associated with size and site of tumor and the presence of hepatic metastases, factors that are significant independent predictors of outcome. The level of FSG at presentation may be useful in planning the nature and extent of the initial evaluation and management in patients with sporadic ZES.

A phase I-II study of isolated hepatic perfusion using melphalan with or without tumor necrosis factor for patients with ocular melanoma metastatic to liver.

There are no satisfactory treatment options for patients with ocular melanoma metastatic to liver, and after liver metastases are identified, median survival is only between 2 and 7 months. Because liver metastases are the sole or life-limiting component of disease in the vast majority of patients who recur, we reasoned that complete vascular isolation and perfusion of the liver might result in clinically meaningful regression of disease. Between September 1994 and July 1999, 22 patients (13 women and 9 men; mean age, 49 years) with ocular melanoma metastatic to liver were treated with a 60-min hyperthermic isolated hepatic perfusion (IHP) using melphalan alone (1.5-2.5 mg/kg, n = 11) or with tumor necrosis factor (TNF, 1.0 mg, n = 11). Via a laparotomy, IHP inflow was via the hepatic artery alone (n = 17) or hepatic artery and portal vein (n = 5) and outflow from an isolated segment of inferior vena cava. Most patients had advanced tumor burden with a mean percentage of hepatic replacement of 25% (range, 10-75%) and a median number of metastatic nodules of 25 (range, 5 to >50). Complete vascular isolation was confirmed in all patients using a continuous intraoperative leak monitoring technique with 131I radiolabeled albumin. There was one treatment mortality (5%). The overall response rate in 21 patients was 62% including 2 radiographic complete responses (9.5%) and 11 partial responses (52%). The overall median duration of response was 9 months (range, 5-50) and was significantly longer in those treated with TNF than without (14 versus 6 months, respectively; P = 0.04). Overall median survival in 22 patients was 11 months. These data indicate that a single 60-min IHP can result in significant regression of advanced hepatic metastases from ocular melanoma. TNF appears to significantly prolong the duration of response.

Augmented capillary leak during isolated hepatic perfusion (IHP) occurs via tumor necrosis factor-independent mechanisms.

Isolated organ perfusion of the liver or extremity with tumor necrosis factor (TNF) and melphalan results in regression of bulky tumors in the majority of patients. The efficacy of TNF in this setting is not known, although data suggest that it may exert antitumor effects primarily on tumor-associated neovasculature. We studied the effects of TNF on capillary leak in liver and tumor tissue during isolated hepatic perfusion (IHP) with melphalan. Twenty-seven patients with unresectable cancer confined to the liver underwent a 60-min hyperthermic IHP using 1.5 mg/kg melphalan alone (n = 7) or with 1.0 mg of TNF (n = 20). Complete vascular isolation was confirmed in all patients using an intraoperative leak monitoring I-131 radiolabeled albumin technique. Samples of tumor and liver were collected just prior to and immediately after IHP. There was no difference in I-131 radiolabeled cpm/g of tissue (cpm) in liver versus tumor at baseline (P2 = 0.44). After IHP, I-131 albumin cpm were higher in tumor versus liver (10,999 +/- 1,976 versus 3,821 +/- 780, respectively; P2 < 0.005). However, I-131 albumin cpm in tumor were not effected by TNF (11,636 +/- 2,518 with TNF versus 9,180 +/- 2,674 without TNF; P2 = 0.59). TNF did not affect melphalan concentrations in tumor (1,883 +/- 540 ng/g versus 1,854 +/- 861 ng/g without TNF; P2 = 0.9). Capillary leak, as reflected by diffusion of I-131 radiolabeled albumin into the interstitial space, is comparable in liver and tumor before IHP but is significantly higher in tumor after IHP. The increased diffusion in the capillary tumor bed must occur through TNF-independent mechanisms such as intrinsic features of tumor neovasculature, hyperthermia, or other unrecognized perfusion-related factors. These data indicate that TNF must continue to be critically evaluated in clinical trials before it is routinely used with melphalan in isolated organ perfusion.

Role of tumor necrosis factor on toxicity and cytokine production after isolated hepatic perfusion.

PURPOSE: Isolated limb or liver perfusion with tumor necrosis factor (TNF) and melphalan results in regression of advanced cancers in the majority of treated patients. However, the contribution of TNF to the efficacy of isolation perfusion with melphalan has not been demonstrated conclusively in random assignment trials. Furthermore, TNF is an inflammatory cytokine and may be associated with significant systemic and regional toxicity. This study was conducted to characterize the toxicity and secondary cytokine production attributable to TNF by comparing these parameters in patients undergoing isolated hepatic perfusion (IHP) using melphalan with or without TNF. EXPERIMENTAL DESIGN: Thirty-two patients with unresectable colorectal cancer confined to the liver underwent a 60-min hyperthermic IHP using 1.5 mg/kg melphalan alone (n = 17) or with 1.0 mg of TNF (n = 15) with inflow via the gastroduodenal artery and outflow via an isolated segment of inferior vena cava. Complete vascular isolation was confirmed using the I-131 radiolabeled albumin-monitoring technique. Post-IHP parameters of hepatic and systemic toxicity and cytokine levels [TNF, interleukin (IL)-6 and IL-8] in perfusate and serum were measured. RESULTS: Levels of IL-6 and IL-8 in perfusate at the end of the 60-min IHP were significantly higher in TNF-treated patients (P < or = 0.001). Peak systemic IL-6 and IL-8 levels post-IHP were also significantly higher in TNF-treated compared with non-TNF-treated patients (P < 0.0001) by 28- and 268-fold, respectively. The peak levels of these cytokines were associated with significantly lower systolic blood pressure and higher heart rate and mean pulmonary artery blood pressure in TNF-treated patients during the first 48 h post-IHP (P < or = 0.03). Serum bilirubin levels were significantly higher (P = 0.017) and platelets lower (P = 0.03) in TNF-treated compared with non-TNF-treated patients. However, elevations in aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase were not significantly different between groups and returned toward baseline within 1 week after IHP. CONCLUSIONS: Addition of TNF to melphalan during IHP results in significant differences in post-IHP production of IL-6 and IL-8 with associated changes in mean arterial blood pressure and greater regional toxicity, as reflected in higher levels of serum bilirubin. However, these measurable differences were transient and did not appear to be of major clinical consequence. Prior to its routine use, the benefit of TNF in isolation perfusion should be demonstrated in random assignment trials.

Serum endostatin levels are elevated and correlate with serum vascular endothelial growth factor levels in patients with stage IV clear cell renal cancer.

Clear cell renal carcinoma (CCRC) is a highly angiogenic tumor known to secrete vascular endothelial cell growth factor (VEGF). Endostatin is an endogenous antiangiogenic agent with antitumor activity in mice. The purpose of this study was to evaluate serum levels of endostatin in normal subjects and in patients with CCRC and to examine the relationship of these levels to circulating VEGF levels. Fifteen patients (mean age, 48 years) on a clinical protocol for stage IV CCRC at the National Cancer Institute were included in the study. Archived prenephrectomy serum samples were analyzed for endostatin and VEGF concentrations. Endostatin and VEGF levels were compared with those of an age-matched group of volunteer blood donors (n = 18) using a competitive enzyme immunoassay. Data were analyzed using the Mann-Whitney U test and the Spearman rank correlation. Median serum endostatin levels were 24.6 ng/ml (range, 15.1-54.0 ng/ml) in CCRC patients versus 14.1 ng/ml (range, 1.0-19.3 ng/ml) in healthy controls (P < 0.0001). Median VEGF levels were 3.4 ng/ml (range, 0.1-11.2 ng/ml) and 2.5 ng/ml (range, 0.1-4.2 ng/ml), respectively (P = 0.065). A highly significant correlation was observed between endostatin and VEGF levels among the CCRC patients (r = 0.81, P = 0.0003) but not among controls (r = -0.22, P = 0.37). Endostatin levels are detectable in serum from healthy subjects as well as from CCRC patients. Levels are significantly elevated and correlate with VEGF levels in CCRC patients. Elucidating the nature of this correlation may lend insight into the regulation of tumor angiogenesis in patients with renal cancer.

Targeted radionuclide therapies for pancreatic cancer.

Pancreatic malignancies, the fourth leading cause of cancer deaths, have an aggressive behavior with poor prognosis, resulting in a 5-year survival rate of only 4%. It is typically a silent malignancy until patients develop metastatic disease. Targeted radionuclide therapies of cancer such as radiolabeled peptides, which bind to the receptors overexpressed by cancer cells and radiolabeled antibodies to tumor-specific antigens provide a viable alternative to chemotherapy and external beam radiation of metastatic cancers. Multiple clinical trials of targeted radionuclide therapy of pancreatic cancer have been performed in the last decade and demonstrated safety and potential efficacy of radionuclide therapy for treatment of this formidable disease. Although a lot of progress has been made in treatment of pancreatic neuroendocrine tumors with radiolabeled (90)Y and (177)Lu somatostatin peptide analogs, pancreatic adenocarcinomas remain a major challenge. Novel approaches such as peptides and antibodies radiolabeled with alpha emitters, pre-targeting, bispecific antibodies and biological therapy based on the radioactive tumorlytic bacteria might offer a potential breakthrough in treatment of pancreatic adenocarcinomas.

Generation of gene-modified T cells reactive against the angiogenic kinase insert domain-containing receptor (KDR) found on tumor vasculature.

The destruction of newly forming tumor vasculature is a promising approach to inhibit tumor growth. The goal of the present study was to investigate whether human lymphocytes gene modified to express a chimeric receptor specific for the angiogenic endothelial cell receptor, KDR, could react against KDR(+) cells. Gene-modified lymphocytes specifically lysed KDR(+) cells and secreted cytokines in response to KDR(+) target cells including human umbilical vein endothelial cells (HUVECs). Anti-KDR lymphocytes induced HUVECs to secrete the chemokine interleukin 8 and upregulate the adhesion molecules VCAM and E-selectin, which may be important in the recruitment of further immune effector cells to tumor. These KDR-specific lymphocytes may be useful in the adoptive immunotherapy of a broad range of cancers by inducing immune-mediated destruction of tumor neovasculature.

Forty-eight-hour fast: the diagnostic test for insulinoma.

Insulinoma causes fasting hypoglycemia due to inappropriate insulin secretion. Its diagnosis is based on demonstrating Whipple's triad during a supervised 72-h fast. For 75 yr, the 72-h fast has been the cornerstone for the diagnosis; however, it has never been critically assessed using newer assays for insulin, C peptide, and proinsulin. Thus, the aim of the current study is to assess the need for a full 72-h fast for the diagnosis of insulinoma. Patients with suspected hypoglycemia with documented glucose concentrations below 45 mg/dL were admitted to the NIH. Data obtained during the supervised fast of patients with pathologically proven insulinoma over a 30-yr period (1970-2000) were reviewed. We identified 127 patients with insulinoma. The average age of patients was 42.7 +/- 15.9 yr, with a predominance of females (62%). 107 patients had a benign tumor, 20 had malignant insulinoma, and 15 patients had multiple endocrine neoplasia type 1. The fast was terminated due to hypoglycemia in 44 patients (42.5%) by 12 h, 85 patients (66.9%) by 24 h, and 120 (94.5%) by 48 h. Seven patients fasted beyond 48 h despite subtle neuroglycopenic symptoms and glucose and insulin concentrations diagnostic of insulinoma. Immunoreactive proinsulin was elevated at the beginning of the fast in 90% of 42 patients. Proinsulin in noninsulinoma, in contrast to insulinoma, patients is usually suppressible; therefore, samples taken in the suppressed state have the greatest diagnostic value. We conclude that with the current available insulin and proinsulin assays, the diagnosis of insulinoma can be made within 48 h. Thus, the 48-h fast should replace the 72-h fast in textbooks and hospital protocols as the new diagnostic standard.

Vaccinia as a vector for tumor-directed gene therapy: biodistribution of a thymidine kinase-deleted mutant.

Tumor-directed gene therapy, such as "suicide gene" therapy, requires high levels of gene expression in a high percentage of tumor cells in vivo to be effective. Current vector strategies have been ineffective in achieving these goals. This report introduces the attenuated (thymidine kinase (TK)-negative) replication-competent vaccinia virus (VV) as a potential vector for tumor-directed gene therapy by studying the biodistribution of VV in animal tumor models. A TK-deleted recombinant VV (Western Reserve strain) expressing luciferase on a synthetic promoter was constructed. Luciferase activity was measured in vitro after transduction of a variety of human and murine tumor cell lines and in vivo after intraperitoneal (i.p.) delivery in C57BL/6 mice with 7-day i.p. tumors (10(6) MC-38 cells). Three other in vivo tumor models were examined for tumor-specific gene expression after intravenous delivery of VV (human melanoma in nude mice, adenocarcinoma liver metastasis in immunocompetent mice, and subcutaneous sarcoma in the rat). In addition, a replication-incompetent vaccinia (1 microg of psoralen and ultraviolet light, 365 nm, 4 minutes) was tested in vitro and in vivo and compared with active virus. Luciferase activity in i.p. tumors at 4 days after i.p. injection of VV was >7000-fold higher than lung, >3000-fold higher than liver, and >250-fold higher than ovary. In addition, intravenous injection of VV resulted in markedly higher tumor luciferase activity compared with any other organ in every model tested (up to 188,000-fold higher than liver and 77,000-fold higher than lung). Inactivation of the virus resulted in negligible gene expression in vivo. In summary, VV has a high transduction efficiency in tumor cells with high levels of gene expression. The results suggest a selective in vivo replication of TK-deleted VV in tumor cells. Replication competent, TK-deleted VV appears to be an ideal vector for testing the in vivo delivery of toxic genes to tumor cells.

Noninvasive fluorescent imaging reliably estimates biomass in vivo.

Whole-body optical imaging of small animals has emerged as a powerful, user friendly, and high-throughput tool for assaying molecular and cellular processes as they occur in vivo. As with any imaging method, the utility of such technology relies on its ability to provide quantitative, biologically meaningful information about the physiologic or pathologic process of interest. Here we used an animal tumor model to evaluate the extent of correlation between noninvasively measured fluorescence and more traditional measurements of biomass (tumor volume and tumor weight). C57/BL6 mice were injected subcutaneously with murine colon adenocarcinoma cells that were engineered to express GFP. Serial measurements of fluorescence intensities were performed with a macroscopic in vivo fluorescence system. The progressive increases in intensity correlated strongly with growth in tumor volume, as determined by caliper measurements (R2 = 0.99). A more stringent correlation was found between fluorescence intensity and tumor weight (R2 = 0.97) than between volume and weight (R2 = 0.89). In a treatment experiment using tumor necrosis factor-alpha, fluorescence intensity (but not tumor volume) was able to differentiate between treated and control groups on day 1 post-treatment. These results validate the ability of noninvasive fluorescent imaging to quantify the number of viable, fluorescent cells in vivo.

Advantages of mRNA amplification for microarray analysis.

Expanding applications of cDNA microarrays such as fine needle aspiration biopsy and laser capture microdissection necessitate the ability to perform arrays with minute starting amounts of RNA. While methods for amplifying RNA have been advocated, the fidelity of array results using amplified material has not been fully validated. Here we demonstrate preserved fidelity in arrays using one or two rounds of mRNA amplification, validated by downstream real-time quantitative PCR. In addition, the quality of the array data was superior to that obtained using total RNA. Based on these results, we recommend routine mRNA amplification for all cDNA microarray-based analysis of gene expression.

Microarray gene expression profiling of angiogenesis inhibitors using the rat aortic ring assay.

The rat aortic ring assay has been previously described as a useful ex vivo model for analyzing the biological activity of various inhibitors of angiogenesis. Rat aortic rings are exposed to antiangiogenic agents for a five-day incubation period. Then, the degree of microvessel outgrowth from the rings is analyzed and quantified. In contrast to most in vitro angiogenesis assays, the rat aortic ring model provides a unique microenvironment to evaluate the interaction of various cell types and biological factors for their influence on angiogenesis. Microarray analysis is an accepted method for the evaluation of gene expression profiles and can be used to better understand changes in gene expression that occur when rat aortic rings are exposed to a particular biological agent. Here we describe a method of using microarray technology to evaluate the modulation of gene expression in angiogenesis using the rat aortic ring assay.