Fernando A. Angarita

Oncolytic Vaccinia Virus Disrupts Tumor-Associated Vasculature in Humans

Efforts to selectively target and disrupt established tumor vasculature have largely failed to date. We hypothesized that a vaccinia virus engineered to target cells with activation of the ras/MAPK signaling pathway (JX-594) could specifically infect and express transgenes (hGM-CSF, β-galactosidase) in tumor-associated vascular endothelial cells in humans. Efficient replication and transgene expression in normal human endothelial cells in vitro required either VEGF or FGF-2 stimulation. Intravenous infusion in mice resulted in virus replication in tumor-associated endothelial cells, disruption of tumor blood flow, and hypoxia within 48 hours; massive tumor necrosis ensued within 5 days. Normal vessels were not affected. In patients treated with intravenous JX-594 in a phase I clinical trial, we showed dose-dependent endothelial cell infection and transgene expression in tumor biopsies of diverse histologies. Finally, patients with advanced hepatocellular carcinoma, a hypervascular and VEGF-rich tumor type, were treated with JX-594 on phase II clinical trials. JX-594 treatment caused disruption of tumor perfusion as early as 5 days in both VEGF receptor inhibitor-naïve and -refractory patients. Toxicities to normal blood vessels or to wound healing were not evident clinically or on MRI scans. This platform technology opens up the possibility of multifunctional engineered vaccinia products that selectively target and infect tumor-associated endothelial cells, as well as cancer cells, resulting in transgene expression, vasculature disruption, and tumor destruction in humans systemically.

VEGF-Mediated Induction of PRD1-BF1/Blimp1 Expression Sensitizes Tumor Vasculature to Oncolytic Virus Infection.

Oncolytic viruses designed to attack malignant cells can in addition infect and destroy tumor vascular endothelial cells. We show here that this expanded tropism of oncolytic vaccinia virus to the endothelial compartment is a consequence of VEGF-mediated suppression of the intrinsic antiviral response. VEGF/VEGFR2 signaling through Erk1/2 and Stat3 leads to upregulation, nuclear localization, and activation of the transcription repressor PRD1-BF1/Blimp1. PRD1-BF1 does not contribute to the mitogenic effects of VEGF, but directly represses genes involved in type I interferon (IFN)-mediated antiviral signaling. In vivo suppression of VEGF signaling diminishes PRD1-BF1/Blimp1 expression in tumor vasculature and inhibits intravenously administered oncolytic vaccinia delivery to and consequent spread within the tumor.

Perioperative measures to optimize margin clearance in breast conserving surgery.

Margin status is one of the most important determinants of local recurrence following breast conserving surgery. The fact that up to 60% of patients undergoing breast conserving surgery require re-excision highlights the importance of optimizing margin clearance. In this review we summarize the following perioperative measures that aim to enhance margin clearance: (1) patient risk stratification, specifically risk factors and nomograms, (2) preoperative imaging, (3) intraoperative techniques including wire-guided localization, radioguided surgery, intraoperative ultrasound-guided resection, intraoperative specimen radiography, standardized cavity shaving, and ink-directed focal re-excision; (4) and intraoperative pathology assessment techniques, namely frozen section analysis and imprint cytology. Novel surgical techniques as well as emerging technologies are also reviewed. Effective treatment requires accurate preoperative planning, developing and implementing a consistent definition of margin clearance, and using tools that provide detailed real-time intraoperative information on margin status.

Locally-advanced primary neuroendocrine carcinoma of the breast: case report and review of the literature

BackgroundPrimary neuroendocrine carcinoma of the breast is a heterogeneous group of rare tumors with positive immunoreactivity to neuroendocrine markers in at least 50% of cells. Diagnosis also requires that other primary sites be ruled out and that the same tumor show histological evidence of a breast in situ component. Primary neuroendocrine carcinoma of the breast rarely presents as locally advanced disease and less frequently with such widespread metastatic disease as described herein. The review accompanying this case report is the first to provide an overview of all the cases of primary neuroendocrine carcinoma of the breast published in the literature and encompasses detailed information regarding epidemiology, histogenesis, clinical and histologic diagnosis criteria, classification, surgical and adjuvant treatment, as well as prognosis. We also provide recommendations for common clinical and histologic pitfalls associated with this tumor.Case presentationWe describe a case of a 51-year-old Hispanic woman initially diagnosed with locally-advanced invasive ductal carcinoma that did not respond to neodjuvant treatment. After undergoing modified radical mastectomy the final surgical pathology showed evidence of alveolar-type primary neuroendocrine carcinoma of the breast. The patient was treated with cisplatin/etoposide followed by paclitaxel/carboplatinum. Thirteen months after surgery the patient is alive, but developed pulmonary, bone, and hepatic metastasis.ConclusionThe breast in situ component of primary neuroendocrine carcinoma of the breast may prevail on a core biopsy samples increasing the probability of underdiagnosing this tumor preoperatively. Being aware of the existence of this disease allows for timely diagnosis and management. Optimal treatment requires simultaneous consideration of both the neuroendocrine and breast in situ tumor features.

Mounting a strategic offense: fighting tumor vasculature with oncolytic viruses

Blood supply within a tumor drives progression and ultimately allows for metastasis. Many anticancer therapies target tumor vasculature, but their individual effectiveness is limited because they induce indirect cell death. Agents that disrupt nascent and/or established tumor vasculature while simultaneously killing cancer cells would certainly have a greater impact. Oncolytic virotherapy utilizes attenuated viruses that replicate specifically within a tumor. They induce cytotoxicity through a combination of direct cell lysis, antitumor immune stimulation, and recently identified antitumor vascular effects. This review summarizes the novel preclinical and clinical evidence regarding the antitumor vascular effects of oncolytic viruses, which include infection and lysis of tumor endothelial cells, natural or genetically engineered antiangiogenic properties, and combination therapy with clinically approved antivascular agents.

Oncolytic vaccinia virus synergizes with irinotecan in colorectal cancer.

Metastatic colorectal cancer (CRC) is complex clinical challenge for which there are limited treatment options. Chemotherapy with or without surgery provides moderate improvements in overall survival and quality of life; nevertheless the 5‐year survival remains below 30%. Oncolytic vaccinia virus (VV) shows strong anti‐tumour activity in models of CRC, however transient delays in disease progression are insufficient to lead to long‐term survival. Here we examined the efficacy of VV with oxaliplatin or SN‐38 (active metabolite of irinotecan) in CRC cell lines in vitro and VV with irinotecan in an orthotopic model of metastatic CRC. Synergistic improvements in in vitro cell killing were observed in multiple cell lines. Combination therapy was well tolerated in tumour‐bearing mice and the median survival was significantly increased relative to monotherapy despite a drug‐dependent decrease in the mean tumour titer. Increased apoptosis following in vitro and in vivo combination therapy was observed. In vitro cell cycle analysis showed increases in S‐phase cells following infection occurred in both infected and uninfected cell populations. This corresponded to a 4‐fold greater increase in apoptosis in the uninfected compared to infected cells following combination therapy. Combination treatment strategies are among the best options for patients with advanced cancers. VV is currently under clinical investigation in patients with CRC and the data presented here suggest that its combination with irinotecan may provide benefit to a subset of CRC patients. Further, investigation of this combination is necessary to determine the tumour characteristics responsible for mediating synergy.

Tumor vascularization is critical for oncolytic vaccinia virus treatment of peritoneal carcinomatosis

Peritoneal carcinomatosis (PC) represents a significant clinical challenge for which there are few treatment options. Oncolytic viruses are ideal candidates for PC treatment because of their high tumor specificity, excellent safety profile and suitability for peritoneal delivery. Here, we described the use of vvDD‐SR‐RFP, a recombinant vaccinia virus, in xenograft and syngeneic models of colorectal PC. Colorectal cancer cell lines were highly susceptible to vvDD‐SR‐RFP replication and cytotoxicity. Intraperitoneal delivery of vvDD‐SR‐RFP on Day 12 to mice with colorectal carcinomatosis significantly improved survival whereas survival was not improved following virus treatment on Day 8, when tumors were smaller. Immunohistochemistry revealed early tumors had a poorly distributed network of blood vessels and lower proliferation index compared to later tumors. Virus infection was also restricted to tumor rims following Day 8 treatment, whereas it was disseminated in tumors treated on Day 12. Additionally, direct infection of tumor endothelium was observed and virus infection correlated with a loss of endothelial staining and induction of cell death. Our results demonstrate that tumor vasculature has a critical role in virus delivery and tumor response. This will have significant implications in the clinical setting, both in understanding timing of therapies and in designing combination treatment strategies.

Bilateral necrotizing fasciitis of the breast following quadrantectomy

Necrotizing fasciitis (NF) is a rare and highly lethal soft-tissue infection that involves the skin, subcutaneous tissue, and fascia. Although it can affect any part of the body, the breast is seldom involved. We describe a case of bilateral NF of the breast following elective quadrantectomy, successfully treated with antibiotics, bilateral mastectomy, and a vacuum-assisted wound closure system.

Oncolytic vaccinia virus as an adjuvant treatment to cytoreductive surgery for malignant peritoneal mesothelioma.

BackgroundMalignant peritoneal mesothelioma (MPM) is an aggressive cancer with a dismal prognosis. Oncolytic viruses are a promising new therapy for cancer because of their ability to kill tumor cells with minimal toxicity to normal tissues. This experimental study aimed to examine the potential of modified vaccinia virus (VV) to treat MPM when administered alone or as an adjuvant treatment to surgery.MethodsTwo aggressive murine mesothelioma cell lines (AC29, AB12), were used. Cell viability and viral cytopathic effects were assessed using MTS and crystal violet assays. Immunocompetent mice were injected intraperitoneally with MPM cells and treated with intraperitoneal VV. Tumor-bearing mice also underwent cytoreductive surgery (CRS) followed by VV (or control) therapy.ResultsThe cytotoxic effects of VV on MPM cell lines was significantly increased compared with the control non-cancer cell line. In both orthotopic models, VV induced tumor regression, prolonging median and long-term survival. VV treatment after incomplete CRS was not superior to VV alone; however, when mice with microscopic disease were treated with VV, further prolongation of median and long-term survivals was observed.ConclusionsVV selectively kills MPM cells in vitro and leads to improved survival and cures in immunocompetent murine models. Higher efficacy of the virus in the microscopic disease context suggests the use of the virus as an adjuvant treatment to complete surgical resection. These promising results justify further studies of VV in humans as a novel treatment for MPM.

Determining the use of prophylactic antibiotics in breast cancer surgeries: a survey of practice

BackgroundProphylactic antibiotics (PAs) are beneficial to breast cancer patients undergoing surgery because they prevent surgical site infection (SSI), but limited information regarding their use has been published. This study aims to determine the use of PAs prior to breast cancer surgery amongst breast surgeons in Colombia.MethodsAn online survey was distributed amongst the breast surgeon members of the Colombian Association of Mastology, the only breast surgery society of Colombia. The scope of the questions included demographics, clinical practice characteristics, PA prescription characteristics, and the use of PAs in common breast surgical procedures.ResultsThe survey was distributed amongst eighty-eight breast surgeons of whom forty-seven responded (response rate: 53.4%). Forty surgeons (85.1%) reported using PAs prior to surgery of which >60% used PAs during mastectomy, axillary lymph node dissection, and/or breast reconstruction. Surgeons reported they targeted the use of PAs in cases in which patients had any of the following SSI risk factors: diabetes mellitus, drains in situ, obesity, and neoadjuvant therapy. The distribution of the self-reported PA dosing regimens was as follows: single pre-operative fixed-dose (27.7%), single preoperative dose followed by a second dose if the surgery was prolonged (44.7%), single preoperative dose followed by one or more postoperative doses for >24 hours (10.6%), and single preoperative weight-adjusted dose (2.1%).ConclusionAlthough this group of breast surgeons is aware of the importance of PAs in breast cancer surgery there is a discrepancy in how they use it, specifically with regards to prescription and timeliness of drug administration. Our findings call for targeted quality-improvement initiatives, such as standardized national guidelines, which can provide sufficient evidence for all stakeholders and therefore facilitate best practice medicine for breast cancer surgery.