T. Pencavel

Synergistic cytotoxicity of oncolytic reovirus in combination with cisplatin-paclitaxel doublet chemotherapy

Oncolytic reovirus is currently under active investigation in a range of tumour types. Early phase studies have shown that this agent has modest monotherapy efficacy and its future development is likely to focus on combination regimens with cytotoxic chemotherapy. Indeed, phase I/II clinical trials have confirmed that reovirus can be safely combined with cytotoxic drugs, including a platin–taxane doublet regimen, which is currently being tested in a phase III clinical trial in patients with relapsed/metastatic head and neck cancer. Therefore, we have tested this triple (reovirus, cisplatin, paclitaxel) combination therapy in a panel of four head and neck cancer cell lines. Using the combination index (CI) method, the triple therapy demonstrated synergistic cytotoxicity in vitro in both malignant and non-malignant cell lines. In head and neck cancer cell lines, this was associated with enhanced caspase 3 and 7 cleavage, but no increase in viral replication. In vitro analyses confirmed colocalisation of markers of reovirus infection and caspase 3. Triple therapy was significantly more effective than reovirus or cisplatin–paclitaxel in athymic nude mice. These data suggest that the combination of reovirus plus platin–taxane doublet chemotherapy has significant activity in head and neck cancer and underpin the current phase III study in this indication.

The surgical management of soft tissue tumours arising in the abdominal wall

BACKGROUND Soft-tissue tumours can occur at almost any site, including the abdominal wall and represent a biologically diverse group of benign and malignant tumours. METHODS A prospectively-kept database was searched to identify all patients with tumours resected that involved the abdominal wall. The histological diagnosis, complication rates and local recurrence rates were reported. Kaplan-Meier analysis of prognostic factors was determined for patients with primary abdominal wall sarcomas. RESULTS Ninety-two patients underwent resection for tumours involving the abdominal wall. Desmoid tumours (n=30) and primary soft-tissue sarcomas (n=25) were the most common pathologies. Of 92 patients undergoing resection 87 required reconstruction of the abdominal wall defect with polypropelene mesh but only 2 patients required reconstruction of the overlying skin. There were no immediate surgical complications in patients who underwent isolated abdominal wall reconstruction and the long term incision hernia rate was 4%. Kaplan-Meier analysis for patients with primary abdominal wall sarcomas showed that local recurrence was higher in tumours>10cm (p=0.0024) and in high grade tumours (p=0.0021). Disease-specific survival was worst in high grade tumours (p=0.0010) and tumours>10cm (p=0.0042). Desmoid tumours did not recur in any patient after abdominal wall resection, irrespective of microscopic margins. CONCLUSIONS Tumours involving the abdominal wall exhibit a wide range of pathologies. Abdominal wall reconstruction can be achieved in the vast majority of cases with mesh reconstruction alone with little surgical morbidity. Sarcomas carry a significant risk of local recurrence. Abdominal wall fibromatosis carries a better prognosis than fibromatosis arising in the extremities.

Combination of a fusogenic glycoprotein, pro-drug activation and oncolytic HSV as an intravesical therapy for superficial bladder cancer

Background:There are still no effective treatments for superficial bladder cancer (SBC)/non-muscle invasive bladder cancer. Following treatment, 20% of patients still develop metastatic disease. Superficial bladder cancer is often multifocal, has high recurrences after surgical resection and recurs after intravesical live Bacillus Calmette–Guérin. OncovexGALV/CD, an oncolytic herpes simplex virus-1, has shown enhanced local tumour control by combining oncolysis with the expression of a highly potent pro-drug activating gene and the fusogenic glycoprotein.Methods:In vitro fusion/prodrug/apoptotic cell-based assays. In vivo orthotopic bladder tumour model, visualised by computed microtomography.Results:Treatment of seven human bladder carcinoma cell lines with the virus resulted in tumour cell killing through oncolysis, pro-drug activation and glycoprotein fusion. OncovexGALV/CD and mitomycin C showed a synergistic effect, whereas the co-administration with cisplatin or gemcitabine showed an antagonistic effect in vitro. Transitional cell cancer (TCC) cells follow an apoptotic cell death pathway after infection with OncovexGALV/CD with or without 5-FC. In vivo results showed that intravesical treatment with OncovexGALV/CD + prodrug (5-FC) reduced the average tumour volume by over 95% compared with controls.Discussion:Our in vitro and in vivo results indicate that OncovexGALV/CD can improve local tumour control within the bladder, and potentially alter its natural history.

Breast sarcoma - a review of diagnosis and management

Sarcoma of the breast is a rare condition. The biological differences from other primary breast tumours necessitate a corresponding difference in approach to diagnostic and management strategies. The rarity of the condition has made clinicopathological study difficult, with most series limited to less than 50 patients. We review the current literature on the diagnosis and management of breast sarcoma, and highlight areas of likely future development.

Synergistic cytotoxicity of radiation and oncolytic Lister strain vaccinia in V600D/E BRAF mutant melanoma depends on JNK and TNF-α signaling

Melanoma is an aggressive skin cancer that carries an extremely poor prognosis when local invasion, nodal spread or systemic metastasis has occurred. Recent advances in melanoma biology have revealed that RAS-RAF-MEK-ERK signaling has a pivotal role in governing disease progression and treatment resistance. Proof-of-concept clinical studies have shown that direct BRAF inhibition yields impressive responses in advanced disease but these are short-lived as treatment resistance rapidly emerges. Therefore, there is a pressing need to develop new targeted strategies for BRAF mutant melanoma. As such, oncolytic viruses represent a promising cancer-specific approach with significant activity in melanoma. This study investigated interactions between genetically-modified vaccinia virus (GLV-1h68) and radiotherapy in melanoma cell lines with BRAF mutant, Ras mutant or wild-type genotype. Preclinical studies revealed that GLV-1h68 combined with radiotherapy significantly increased cytotoxicity and apoptosis relative to either single agent in V600DBRAF/V600EBRAF mutant melanoma in vitro and in vivo. The mechanism of enhanced cytotoxicity with GLV-1h68/radiation (RT) was independent of viral replication and due to attenuation of JNK, p38 and ERK MAPK phosphorylation specifically in BRAF mutant cells. Further studies showed that JNK pathway inhibition sensitized BRAF mutant cells to GLV-1h68-mediated cell death, mimicking the effect of RT. GLV-1h68 infection activated MAPK signaling in V600DBRAF/V600EBRAF mutant cell lines and this was associated with TNF-α secretion which, in turn, provided a prosurvival signal. Combination GLV-1h68/RT (or GLV-1h68/JNK inhibition) caused abrogation of TNF-α secretion. These data provide a strong rationale for combining GLV-1h68 with irradiation in V600D/EBRAF mutant tumors.

Oncolytic Vaccinia virus and radiotherapy in head and neck cancer

OBJECTIVE Oncolytic forms of attenuated Vaccinia virus are now in clinical development, assessing the compatibility of this novel treatment with radiotherapy may reveal exploitable synergistic relationships. MATERIALS AND METHODS In vitro analyses of cell killing, cell cycle effects and caspase activation were carried out on HN3, HN5, CAL27, Detroit, SIHN5B, and PJ41 cells. In vivo studies of the virus and X-radiation were performed on H&N xenografts in CD1 nude mice. RESULTS Cell killing in vitro was demonstrated to be dose- and time-dependent. Infection causes an increase in S-phase and sub-G1 cells. A dose dependent increase in active caspase-3 indicated induction of apoptosis. Xenografts injected with Vaccinia stabilised and frequently completely regressed. Combination with radiation generated additional cell death, induction of caspase activity and in vivo further improved long term regression rates. CONCLUSIONS These data support continued exploration of this therapy combination and indicates potential for clinical trials in head and neck cancer.

Treatment for breast sarcoma: A large, single-centre series *

AIMS To report outcomes in breast sarcoma in the context of a major series from a tertiary referral centre. METHODS Retrospective analysis was performed on patients with histologically-proven breast sarcoma treated between 1996 and 2006. Kaplan-Meier survival curves were constructed and differences assessed by Log-Rank and Wilcoxon tests. RESULTS 63 patients were identified; 57 underwent treatment with curative intent. 24 patients had undergone previous radiotherapy. 36 patients who underwent primary surgery elsewhere were referred for further treatment, of which 22 had at least one involved margin from primary resection. Surgery performed and margins status varied between patients undergoing primary surgery at this institution (n = 21; WLE = 8, mastectomy = 12, chest wall resection = 1, involved margins = 2 [10%]) or at a referring institution (n = 36; lumpectomy = 25, mastectomy = 11, involved margins = 22 [61%]), although there was no difference in tumour size or previous radiotherapy status. Previous irradiation was associated with poor prognosis. A greater proportion of these patients required primary mastectomy to ensure adequate clearance; the majority of the post-irradiation tumours were angiosarcomas (15/19) and significantly more relapsed locally (P < 0.001). All patient disease-free survival (DFS) rates were 71% at 2 and 42% at 5 years. DFS improved when primary surgery was undertaken at a high-volume sarcoma unit; 2-yr 84%vs75%; 5-yr 58%vs37%. There was a trend towards worse DFS with increasing size and increasing grade of tumour but this did not attain significance. CONCLUSIONS Radiation-induced breast sarcoma has worse local recurrence rates compared to primary breast sarcoma. Involved margins were fewer at a specialist unit, which may translate into improved outcome.

Oncolytic vaccinia virus combined with radiotherapy induces apoptotic cell death in sarcoma cells by down-regulating the inhibitors of apoptosis

Advanced extremity melanoma and sarcoma present a significant therapeutic challenge, requiring multimodality therapy to treat or even palliate disease. These aggressive tumours are relatively chemo-resistant, therefore new treatment approaches are urgently required. We have previously reported on the efficacy of oncolytic virotherapy (OV) delivered by isolated limb perfusion. In this report, we have improved therapeutic outcomes by combining OV with radiotherapy. In vitro, the combination of oncolytic vaccinia virus (GLV-1h68) and radiotherapy demonstrated synergistic cytotoxicity. This effect was not due to increased viral replication, but mediated through induction of intrinsic apoptosis. GLV-1h68 therapy downregulated the anti-apoptotic BCL-2 proteins (MCL-1 and BCL-XL) and the downstream inhibitors of apoptosis, resulting in cleavage of effector caspases 3 and 7. In an in vivo ILP model, the combination of OV and radiotherapy significantly delayed tumour growth and prolonged survival compared to single agent therapy. These data suggest that the virally-mediated down-regulation of anti-apoptotic proteins may increase the sensitivity of tumour cells to the cytotoxic effects of ionizing radiation. Oncolytic virotherapy represents an exciting candidate for clinical development when delivered by ILP. Its ability to overcome anti-apoptotic signals within tumour cells points the way to further development in combination with conventional anti-cancer therapies.

Locoregional intravascular viral therapy of cancer: precision guidance for Paris's arrow?

Viral therapy of cancer includes strategies such as viral transduction of tumour cells with ‘suicide genes’, using viral infection to trigger immune-mediated tumour cell death and using oncolytic viruses for their direct anti-tumour action. However, problems still remain in terms of adequate viral delivery to tumours. A role is also emerging for single-organ isolation and perfusion. Having begun with the advent of isolated limb perfusion for extremity malignancy, experimental systems have been developed for the perfusion of other organs, particularly the liver, kidneys and lungs. These are beginning to be adopted into clinical treatment pathways. The combination of these two modalities is potentially significant. Locoregional perfusion increases the exposure of tumour cells to viral agents. In addition, the avoidance of systemic elimination through the immune and reticulo-endothelial systems should provide a mechanism for increased transduction/infection of target cells. The translation of laboratory research to clinical practice would occur within the context of perfusion programmes, which are already established in the clinic. Many of these programmes include the use of vasoactive cytokines such as tumour necrosis factor-α, which may have an effect on viral uptake. Evidence of activation of specific anti-tumour immunological responses by intratumoural and other existing methods of viral administration raises the intriguing possibility of a locoregional therapy, with the ability to affect distant sites of disease. In this review, we examined the state of the literature in this area and summarized current findings before indicating likely areas of continuing interest.

Isolated limb perfusion with biochemotherapy and oncolytic virotherapy combines with radiotherapy and surgery to overcome treatment resistance in an animal model of extremity soft tissue sarcoma

The management of locally advanced or recurrent extremity sarcoma often necessitates multimodal therapy to preserve a limb, of which isolated limb perfusion (ILP) is a key component. However, with standard chemotherapeutic agents used in ILP, the duration of response is limited. Novel agents or treatment combinations are urgently needed to improve outcomes. Previous work in an animal model has demonstrated the efficacy of oncolytic virotherapy when delivered by ILP and, in this study, we report further improvements from combining ILP‐delivered oncolytic virotherapy with radiation and surgical resection. In vitro, the combination of radiation with an oncolytic vaccinia virus (GLV‐1h68) and melphalan demonstrated increased cytotoxicity in a panel of sarcoma cell lines. The effects were mediated through activation of the intrinsic apoptotic pathway. In vivo, combinations of radiation, oncolytic virotherapy and standard ILP resulted in delayed tumour growth and prolonged survival when compared with standard ILP alone. However, local disease control could only be secured when such treatment was combined with surgical resection, the timing of which was crucial in determining outcome. Combinations of oncolytic virotherapy with surgical resection and radiation have direct clinical relevance in extremity sarcoma and represent an exciting prospect for improving outcomes in this pathology.