Cyclooxygenase-2 inhibition suppresses alphavbeta6 integrin-dependent oral squamous carcinoma invasion.

Worldwide oral squamous cell carcinoma (OSCC) represents about 5.5% of all malignancies, with approximately 30,000 new cases each year in the United States. The integrin alpha(v)beta(6) and the enzyme cyclooxygenase-2 (COX-2) are implicated in OSCC progression and have been suggested as possible therapeutic targets. Each protein also is reported to identify dysplasias at high risk of malignant transformation, and current clinical trials are testing the efficacy of nonsteroidal anti-inflammatory drugs (NSAID) at preventing OSCC development. Given the probable increased expression of alpha(v)beta(6) and COX-2 in OSCC and the inhibition of several integrins by NSAIDs, we investigated whether NSAIDs affected alpha(v)beta(6)-dependent cell functions. We found that expression of both alpha(v)beta(6) and COX-2 was significantly higher in OSCC compared with oral epithelial dysplasias. Neither protein preferentially identified those dysplastic lesions that became malignant. Using OSCC cell lines, modified to express varying levels of alpha(v)beta(6), we assessed the effect of COX-2 inhibition on cell invasion. We found that the COX-2 inhibitor NS398 inhibited specifically alpha(v)beta(6)-dependent, but not alpha(v)beta(6)-independent, OSCC invasion in vitro and in vivo, and this effect was modulated through prostaglandin E(2) (PGE(2))-dependent activation of Rac-1. Transient expression of constitutively active Rac-1, or addition of the COX-2 metabolite PGE(2), prevented the anti-invasive effect of NS398. Conversely, RNA interference down-regulation of Rac-1 inhibited alpha(v)beta(6)-dependent invasion. These findings suggest that COX-2 and alpha(v)beta(6) interact in promoting OSCC invasion. This is a novel mechanism that, given the ubiquity of alpha(v)beta(6) expression by head and neck cancers, raises the possibility that NSAIDs could protect against OSCC invasion.

Phase II trial of vinorelbine and oxaliplatin as first-line therapy in malignant pleural mesothelioma.

UNLABELLED: The incidence of malignant pleural mesothelioma (MPM) is increasing. Treatment options are limited, although recently published data have offered cause for optimism. We reported a response rate of 24% with low toxicity for single agent vinorelbine. Here we report a phase II trial of vinorelbine with oxaliplatin (VO) in patients with untreated MPM. Chemotherapy consisted of vinorelbine 30 mg/m(2), days 1 and 8 of a 21-day-cycle, and oxaliplatin 130 mg/m(2), day 1. Treatment continued up to six cycles. The primary endpoint was objective response. Secondary endpoints were toxicity, progression-free and overall survival. Responses were assessed by modified RECIST criteria. Twenty-six patients were enrolled. There were six partial remissions, 17 patients with stable disease, and three patients with PD. Response rate was 23% (95% confidence interval 9-44%). Median number of cycles delivered was four. Progression-free survival from first treatment was 4.7 months, and overall survival was 8.8 months. One-year-survival was 27%. Toxicity (% of patients with at least one episode of grade 3 or 4 toxicity): neutropenia 18%, phlebitis 12%, malaise 12%, anorexia 12%, nausea and vomiting 12%, constipation 6%. Quality of life assessed by Rotterdam symptom checklist was associated with stabilization or improvement of psychological well-being and lung symptoms in the majority of patients, but deterioration in physical symptoms. CONCLUSION: VO has activity in MPM with most patients responding or having stable disease, although this doublet is associated with significant toxicity.

Low-dose continuous chemotherapy for metastatic melanoma: a phase II trial.

The prognosis of patients with metastatic melanoma remains poor and there is a need to develop new regimens with low toxicity. We investigated a novel outpatient regimen combining oral and intravenous chemotherapy with daily subcutaneous bleomycin. Twenty-nine chemotherapy-naive patients with metastatic melanoma were treated with a novel regimen consisting of low dose lomustine, daily subcutaneous bleomycin, chlorambucil, methotrexate and vinblastine with tamoxifen for an 8 week cycle (LBCMVT-56). A median of two cycles were given until disease progression or grade 3/4 toxicity. Five out of 29 (17%) patients had an objective response, of whom two (7%) had a complete response and remain progression-free after 2 years of follow-up. The median overall survival was 7.3 months. A symptomatic response was seen in 11 out of 29 patients (38%). Toxicity was acceptable, with grade 3/4 haematological toxicity seen in 25% of cycles, infection requiring intravenous antibiotics in 11% of cycles, and pulmonary toxicity seen in 4% of cycles. Hospitalization was required in 21% of the patients at some point during the treatment, most commonly for neutropenic sepsis. LBCMVT-56 chemotherapy is a novel outpatient regimen producing occasional durable complete responses in a patient group with a poor prognosis. The median survival is similar to that obtained with dacarbazine, though the toxicity is greater.

Measuring invasion in an organotypic model.

Organotypic cultures are in vitro models that can be used to study the interactions between tumour and stromal cells. Collective tumour cell invasion in organotypic assays resembles that seen in human tissues in vivo, suggesting physiological relevance. A qualitative, pathological description of such invasion may be inadequate, and there is therefore a need to accurately quantify the degree of invasion. Although the simplest method to quantify invasion is to measure maximum invasive depth, this ignores the importance of the pattern of tumour invasion, which often reflects tumour aggressiveness. We use image analysis software to analyse organotypic invasion objectively, taking into account the average depth of tumour invasion, and the number and area of invading tumour islands. The product of these parameters is termed the "invasion index," which maximises differences in invasion and also reflects the invasive pattern of the gel in a way that none of the individual parameters does alone.

Cell migration and invasion assays.

A number of in vitro assays have been developed to study tumor cell motility. Historically, assays have been mainly monocellular, where carcinoma cells are studied in isolation. Scratch assays can be used to study the collective and directional movement of populations of cells, whereas two chamber assays lend themselves to the analysis of chemotactic/haptotactic migration and cell invasion. However, an inherent disadvantage of these assays is that they grossly oversimplify the complex process of invasion, lacking the tumor structural architecture and stromal components. Organotypic assays, where tumor cells are grown at an air/liquid interface on gels populated with stromal cells, are a more physiologically relevant method for studying 3-dimensional tumor invasion.