Kaitlyn J. Kelly

Paracrine Regulation of Pancreatic Cancer Cell Invasion by Peripheral Nerves

BACKGROUND The ability of cancer to infiltrate along nerves is a common clinical observation in pancreas, head and neck, prostate, breast, and gastrointestinal carcinomas. For these tumors, nerves may provide a conduit for local cancer progression into the central nervous system. Although neural invasion is associated with poor outcome, the mechanism that triggers it is unknown. METHODS We used an in vitro Matrigel dorsal root ganglion and pancreatic cancer cell coculture model to assess the dynamic interactions between nerves and cancer cell migration and the role of glial cell-derived neurotrophic factor (GDNF). An in vivo murine sciatic nerve model was used to study how nerve invasion affects sciatic nerve function. RESULTS Nerves induced a polarized neurotrophic migration of cancer cells (PNMCs) along their axons, which was more efficient than in the absence of nerves (migration distance: mean = 187.1 microm, 95% confidence interval [CI] = 148 to 226 microm vs 14.4 microm, 95% CI = 9.58 to 19.22 microm, difference = 143 microm; P < .001; n = 20). PNMC was induced by secretion of GDNF, via phosphorylation of the RET-Ras-mitogen-activated protein kinase pathway. Nerves from mice deficient in GDNF had reduced ability to attract cancer cells (nerve invasion index: wild type vs gdnf+/-, mean = 0.76, 95% CI = 0.75 to 0.77 vs 0.43, 95% CI = 0.42 to 0.44; P < .001; n = 60-66). Tumor specimens excised from patients with neuroinvasive pancreatic carcinoma had higher expression of the GDNF receptors RET and GRFalpha1 as compared with normal tissue. Finally, systemic therapy with pyrazolopyrimidine-1, a tyrosine kinase inhibitor targeting the RET pathway, suppressed nerve invasion toward the spinal cord and prevented paralysis in mice. CONCLUSION These data provide evidence for paracrine regulation of pancreatic cancer invasion by nerves, which may have important implications for potential therapy directed against nerve invasion by cancer.

Enhancement of Oncolytic Properties of Recombinant Newcastle Disease Virus Through Antagonism of Cellular Innate Immune Responses

Newcastle disease virus (NDV) has been previously shown to possess oncolytic activity, causing specific lysis of cancerous but not normal cells. Here we show that despite these findings, the oncolytic efficiency of naturally occurring NDV strains can still be relatively low, as many tumors exhibit strong innate immune responses that suppress viral replication and spread. To overcome this problem, we generated a recombinant fusogenic NDV expressing influenza NS1 protein, a protein exhibiting interferon (IFN)-antagonist and antiapoptotic functions in human and mouse cells. Interestingly, the resultant virus was dramatically enhanced in its ability to form syncytia, lyse a variety of human and mouse tumor cell lines, and suppressed the induction of the cellular IFN responses. Using the aggressive syngeneic murine melanoma model, we show that the NDV-NS1 virus is more effective than virus not expressing NS1 in clearing the established footpad tumors and results in higher overall long-term animal survival. In addition, mice treated with NDV-NS1 exhibited no signs of toxicity to the virus and developed tumor-specific cytotoxic T lymphocyte (CTL) responses. These findings demonstrate that modulation of innate immune responses by NDV results in enhancement of its oncolytic properties and warrant further investigation of this strategy in design of oncolytic NDV vectors against human tumors.

Novel oncolytic agent GLV-1h68 is effective against malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) is a fatal disease with a median survival of less than 14 months. For the first time, a genetically engineered vaccinia virus is shown to produce efficient infection, replication, and oncolytic effect against MPM. GLV-1h68 is a replication-competent engineered vaccinia virus carrying transgenes encoding Renilla luciferase, green fluorescent protein (both inserted at the F14.5L locus), beta-galactosidase (inserted at the J2R locus, which encodes thymidine kinase), and beta-glucuronidase (at the A56R locus, which encodes hemagglutinin). This virus was tested in six human MPM cell lines (MSTO-211H, VAMT, JMN, H-2373, H-2452, and H-2052). GLV-1h68 successfully infected all cell lines. For the most sensitive line, MSTO-211H, expression of green fluorescent protein (GFP) started within 4 hr with increasing intensity over time until nearly 100% of cells expressed GFP at 24 hr. All cell lines were sensitive to killing by GLV-1h68, with the degree of sensitivity predictable by infectivity assay. Even the most resistant cell line exhibited 44 +/- 3.8% cell survival by day 7 when infected at a multiplicity of infection of 1.0. Viral proliferation assays demonstrated 2-to 4-fold logarithmic replication of GLV-1h68 in the cell lines tested. In an orthotopic model, GLV-1h68 effectively prevented development of cachexia and tumor-related morbidity, reduced tumor burden, and cured MPM in both early and late treatment groups. GLV-1h68 was successfully used to treat MPM in vitro and in an orthotopic model (in vivo). These promising results warrant clinical investigation of GLV-1h68 as a novel agent in the treatment of MPM.

Genetically-engineered Newcastle Disease Virus for malignant melanoma therapy

Despite the advances in cancer therapies in the past century, malignant melanoma continues to present a significant clinical challenge due to lack of chemotherapeutic response. Systemic therapy with immunostimulatory agents such as interferon and interleukin-2 (IL-2) has shown some promise, though each is associated with significant side effects. Over the past 50 years, oncolytic Newcastle disease virus (NDV) has emerged as an alternative candidate for cancer therapy. The establishment of reverse-genetics systems for the virus has allowed us to further manipulate the virus to enhance its oncolytic activity. Introduction of immunomodulatory molecules, especially IL-2, into the NDV genome was shown to enhance the oncolytic potential of the virus in a murine syngeneic colon carcinoma model. We hypothesize that a recombinant NDV expressing IL-2 would be an effective agent for therapy of malignant melanoma. We show that recombinant NDV possesses a strong cytolytic activity against multiple melanoma cell lines, and is effective in clearing established syngeneic melanoma tumors in mice. Moreover, introduction of murine IL-2 into NDV significantly enhanced its activity against syngeneic melanomas, resulting in increased overall animal survival and generation of antitumor immunity. These findings warrant further investigations of IL-2-expressing NDV as an antimelanoma agent in humans.

Endoscopic ultrasound after preoperative chemoradiation can help identify patients who benefit maximally after surgical esophageal resection.

BACKGROUND:We investigated whether differences in postoperative survival exist based on the presence and site of residual tumor (esophagus vs regional lymph nodes) after preoperative chemoXRT in patients with esophageal cancer. Based on these data, we reevaluated the role of EUS in identifying patients who maximally benefit from surgical esophageal resection after preoperative chemoXRT.METHODS:We studied 97 consecutive esophageal cancer patients treated with preoperative chemoXRT and a potentially curative surgical procedure between 1998 to 2001. All patients had EUS examination prior to chemoXRT and 53 had a repeat EUS examination after chemoXRT but prior to surgery. Surgical resection specimens were analyzed for absence or presence of residual tumor and its location.RESULTS:Patients with residual tumor in the esophagus (pathT1-3N0) and patients without residual tumor (pathT0N0) had similar cumulative survival (p = 0.92). Patients with residual cancer in lymph nodes showed a trend toward shorter cumulative survival compared to patients without residual tumor in lymph nodes (p = 0.086). The actuarial survival in pathN1 group was lower than pathN0 group at 1, 2, and 3 yr. Patients with significant residual lymphadenopathy detected by EUS after therapy had significantly worse postoperative survival compared to patients with no residual lymphadenopathy (p = 0.028). In eight patients, we found that reliable cytologic identification of residual malignancy was technically feasible by EUS-FNA after chemoradiation therapy.CONCLUSIONS:Following preoperative chemoXRT and surgery, patients with residual tumor in the regional lymph nodes have lower actuarial survival at 1, 2, and 3 yr after surgery, compared to patients with path CR or with residual tumor only in the esophagus. EUS and EUS-guided FNA can be helpful in identifying residual tumor in the lymph nodes after preoperative chemoXRT to select patients who benefit maximally from surgery.

Imaging a Genetically Engineered Oncolytic Vaccinia Virus (GLV-1h99) Using a Human Norepinephrine Transporter Reporter Gene

Purpose: Oncolytic viral therapy continues to be investigated for the treatment of cancer, and future studies in patients would benefit greatly from a noninvasive modality for assessing virus dissemination, targeting, and persistence. The purpose of this study was to determine if a genetically modified vaccinia virus, GLV-1h99, containing a human norepinephrine transporter (hNET) reporter gene, could be sequentially monitored by [123I]metaiodobenzylguanidine (MIBG) γ-camera and [124I]MIBG positron emission tomography (PET) imaging. Experimental Design: GLV-1h99 was tested in human malignant mesothelioma and pancreatic cancer cell lines for cytotoxicity, expression of the hNET protein using immunoblot analysis, and [123I]MIBG uptake in cell culture assays. In vivo [123I]MIBG γ-camera and serial [124I]MIBG PET imaging was done in MSTO-211H orthotopic pleural mesothelioma tumors. Results: GLV-1h99 successfully infected and provided dose-dependent levels of transgene hNET expression in human malignant mesothelioma and pancreatic cancer cells. The time course of [123I]MIBG accumulation showed a peak of radiotracer uptake at 48 hours after virus infection in vitro. In vivo hNET expression in MSTO-211H pleural tumors could be imaged by [123I]MIBG scintigraphy and [124I]MIBG PET 48 and 72 hours after GLV-1h99 virus administration. Histologic analysis confirmed the presence of GLV-1h99 in tumors. Conclusion: GLV-1h99 shows high mesothelioma tumor cell infectivity and cytotoxic efficacy. The feasibility of imaging virus-targeted tumor using the hNET reporter system with [123I]MIBG γ-camera and [124I]MIBG PET was shown in an orthotopic pleural mesothelioma tumor model. The inclusion of human reporter genes into recombinant oncolytic viruses enhances the potential for translation to clinical monitoring of oncolytic viral therapy.

Imaging of Lymph Node Micrometastases Using an Oncolytic Herpes Virus and [18F]FEAU PET

Background In patients with melanoma, knowledge of regional lymph node status provides important information on outlook. Since lymph node status can influence treatment, surgery for sentinel lymph node (SLN) biopsy became a standard staging procedure for these patients. Current imaging modalities have a limited sensitivity for detection of micrometastases in lymph nodes and, therefore, there is a need for a better technique that can accurately identify occult SLN metastases. Methodology/Principal Findings B16-F10 murine melanoma cells were infected with replication-competent herpes simplex virus (HSV) NV1023. The presence of tumor-targeting and reporter-expressing virus was assessed by [18F]-2′-fluoro-2′-deoxy-1-β-D-β-arabinofuranosyl-5-ethyluracil ([18F]FEAU) positron emission tomography (PET) and confirmed by histochemical assays. An animal foot pad model of melanoma lymph node metastasis was established. Mice received intratumoral injections of NV1023, and 48 hours later were imaged after i.v. injection of [18F]FEAU. NV1023 successfully infected and provided high levels of lacZ transgene expression in melanoma cells. Intratumoral injection of NV1023 resulted in viral trafficking to melanoma cells that had metastasized to popliteal and inguinal lymph nodes. Presence of virus-infected tumor cells was successfully imaged with [18F]FEAU-PET, that identified 8 out of 8 tumor-positive nodes. There was no overlap between radioactivity levels (lymph node to surrounding tissue ratio) of tumor-positive and tumor-negative lymph nodes. Conclusion/Significance A new approach for imaging SLN metastases using NV1023 and [18F]FEAU-PET was successful in a murine model. Similar studies could be translated to the clinic and improve the staging and management of patients with melanoma.

Real-time intraoperative detection of melanoma lymph node metastases using recombinant vaccinia virus GLV-1h68 in an immunocompetent animal model

There is a clinical need for improved intraoperative detection of lymph node metastases from malignant melanoma (MM). We aimed to investigate the use of recombinant vaccinia virus GLV‐1h68, expressing green fluorescent protein (GFP), for real‐time intraoperative detection of melanoma lymph node metastases in an immunocompetent animal model. Mice bearing foot pad tumors received intratumoral injections of GLV‐1h68, and 48 hr later were evaluated for popliteal lymph node metastasis using noninvasive bioluminescence imaging and fluorescence imaging. Histologic analysis of lymph nodes was performed to determine sensitivity and specificity of virus‐mediated detection. Intratumoral injection of GLV‐1h68 into primary foot pad melanoma tumors resulted in viral transmission to popliteal lymph nodes, infection of lymphatic metastases, and transgene expression that was reliably and easily detected. Histologic confirmation demonstrated favorable operating characteristics of this assay (sensitivity 80%, specificity 100%, positive predictive value [PPV] 100%, negative predictive value [NPV] 91%). Detection of marker gene expression by GLV‐1h68 allowed the detection of lymphatic metastases in an immunocompetent animal model of MM. This assay is rapid, sensitive, specific and easy to perform and interpret. As a candidate gene therapy virusfor killing cancer, GLV‐1h68 may also have significant concomitant diagnostic utility in the staging of cancer patients.

Detection of micrometastases in peritoneal washings of gastric cancer patients by the reverse transcriptase polymerase chain reaction

BackgroundGastric cancer patients with positive (+) peritoneal cytology have a prognosis similar to stage IV patients. We studied the ability of quantitative reverse transcriptase polymerase chain reaction (RT-PCR) to detect peritoneal micrometastases in patients undergoing staging laparoscopy.MethodsPeritoneal washings were obtained prospectively from 34 patients with gastric adenocarcinoma undergoing staging laparoscopy and 6 patients undergoing laparoscopy for benign disease. Each sample underwent cytologic and RTPCR analysis for tumor markers: carcinoembryonic antigen (CEA), cytokeratin 20 (CK20), survivin, and MUC2. Markers were evaluated on the basis of their deviance from the ideal marker.ResultsPathologic stages for the gastric cancer patients were: stage I, 9 (27%); stage II, 7 (21%); stage III, 15 (44%); and stage IV, 3 (9%). The four cytology (+) patients were: stage II, 1; stage III, 1; and stage IV, 2. Fifteen patients were RTPCR (+), including all cytology (+) patients. The optimal threshold for cycle amplification was 35, based on a receiver operating characteristic curve. CEA had the smallest deviance.ConclusionRT-PCR using a panel of tumor markers, including CEA, detects (+) cytology. The clinical significance of “false-positive” overexpression of CEA, survivin, or CK20 but cytology (−) remains to be defined. RT-PCR could represent a more sensitive method than cytology for detection of subclinical peritoneal tumor dissemination; this may be useful in improving patient selection for operative management and clinical trials.

Comparison of Perioperative Radiation Therapy and Surgery Versus Surgery Alone in 204 Patients With Primary Retroperitoneal Sarcoma: A Retrospective 2-Institution Study.

OBJECTIVE To compare outcomes of patients with retroperitoneal or pelvic sarcoma treated with perioperative radiation therapy (RT) versus those treated without perioperative RT. BACKGROUND RT for retroperitoneal or pelvic sarcoma is controversial, and few studies have compared outcomes with and without RT. METHODS Prospectively maintained databases were reviewed to retrospectively compare patients with primary retroperitoneal or pelvic sarcoma treated during 2003-2011. Multivariate Cox regression models were used to assess associations with the primary endpoints: local recurrence-free survival (LRFS) and disease-specific survival. RESULTS At 1 institution, 172 patients were treated with surgery alone, whereas at another institution 32 patients were treated with surgery and perioperative proton beam RT or intensity-modulated RT with or without intraoperative RT. The groups were similar in age, tumor size, grade, and margin status (all P > 0.08). The RT group had a higher percentage of pelvic tumors (P = 0.03) and a different distribution of histologies (P = 0.04). Perioperative morbidity was higher in the RT group (44% vs 16% of patients; P = 0.004). After a median follow-up of 39 months, 5-year LRFS was 91% (95% confidence interval, 79%-100%) in the RT group and 65% (57%-74%) in the surgery-only group (P = 0.02). On multivariate analysis, RT was associated with better LRFS (hazard ratio, 0.26; P = 0.03). Five-year disease-specific survival was 93% (95% confidence interval, 82%-100%) in the RT group and 85% (78%-92%) in the surgery-only group (P = 0.3). CONCLUSIONS The addition of advanced-modality RT to surgery for primary retroperitoneal or pelvic sarcoma was associated with improved LRFS, although this did not translate into significantly better disease-specific survival. This treatment strategy warrants further investigation in a randomized trial.