Current therapy for malignant mesothelioma

Pyroptosis: A new frontier in cancer

Pyroptosis is an inflammatory form of cell death triggered by certain inflammasomes, leading to the cleavage of gasdermin D (GSDMD) and activation of inactive cytokines like IL-18 and IL-1β. Pyroptosis has been reported to be closely associated to some diseases like atherosclerosis and diabetic nephropathy. Recently, some studies found that pyroptosis can influence the proliferation, invasion and metastasis of tumor, which regulated by some non-coding RNAs and other molecules. Hence, we provided an overview of morphological and molecular characteristics of pyroptosis. We also focus on mechanism of regulating pyroptosis in tumor cells as well as the potential roles of pyroptosis in cancer to explore potential diagnostic markers in cancers contributing to the prevention and treatment in cancers.

Inflammasome Modulation by Chemotherapeutics in Malignant Mesothelioma

Malignant mesothelioma (MM) is a fatal disease in dire need of therapy. The role of inflammasomes in cancer is not very well studied, however, literature supports both pro-and anti-tumorigenic effects of inflammasomes on cancer depending upon the type of cancer. Asbestos is a causative agent for MM and we have shown before that it causes inflammasome priming and activation in mesothelial cells. MM tumor cells/tissues showed decreased levels of inflammasome components like NLRP3 and caspase-1 as compared to human mesothelial cells or normal tissue counterpart of tumor. Based on our preliminary findings we hypothesized that treatment of MMs with chemotherapeutic drugs may elevate the levels of NLRP3 and caspase-1 resulting in increased cell death by pyroptosis while increasing the levels of IL-1β and other pro-inflammatory molecules. Therefore, a combined strategy of chemotherapeutic drug and IL-1R antagonist may play a beneficial role in MM therapy. To test our hypothesis we used two human MM tumor cell lines (Hmeso, H2373) and two chemotherapeutic drugs (doxorubicin, cisplatin). Through a series of experiments we showed that both chemotherapeutic drugs caused increases in NLRP3 levels, caspase-1 activation, pyroptosis and pro-inflammatory molecules released from MM cells. In vivo studies using SCID mice and Hmeso cells showed that tumors were smaller in combined treatment group of cisplatin and IL-1R antagonist (Anakinra) as compared to cisplatin alone or untreated control groups. Taken together our study suggests that chemotherapeutic drugs in combination with IL-1R antagonist may have a beneficial role in MM treatment.

Pemetrexed Therapy for Malignant Pleural Mesothelioma

OBJECTIVE:

To review pemetrexed, a novel multi-targeted antifolate agent.

DATA SOURCES:

A literature search was conducted (1985–September 2004) using MEDLINE and CANCERLIT. Recent abstracts from the American Society of Clinical Oncology were also included, along with the manufacturer's information. Key words were pemetrexed, LY-231514, Alimta, multi-targeted antifolate, malignant pleural mesothelioma.

STUDY SELECTION AND DATA EXTRACTION:

Relevant information on pharmacology, pharmacokinetics, and safety and efficacy of pemetrexed from clinical trials was selected.

DATA SYNTHESIS:

Pemetrexed inhibits folate metabolism and purine/pyrimidine synthesis. Based on Phase I and II trials, pemetrexed has antitumor activity in solid tumors such as lung, colorectal, and cervical. A pivotal Phase III study in patients with malignant pleural mesothelioma (MPM) demonstrated survival superiority of pemetrexed—cisplatin regimen versus cisplatin.

CONCLUSIONS:

Pemetrexed is a promising new drug for the treatment of solid malignancies, most notably MPM.

Factors influencing long-term survival in mesothelioma patients--results of the German mesothelioma register

Between 1987 and 2000, the German mesothelioma register recorded a total of 4,455 patients with malignant mesotheliomas. Survival times for 498 (11.2%) patients were available; 155 patients (study group, 3.5% of the total group) survived for more than 2 years and 343 patients (control group, 7.7% of the total group) survived for fewer than 24 months. Male patients were over-represented in both groups, with 13% of women in the study and 4.4% in the control group. The proportion of pleural mesotheliomas was more than 90% in both groups, with peritoneal cases comprising 6.5% in the study group and 3.2% in the control group. Histologically, the epithelioid subtype was represented in 58% of the study group, whereas the biphasic subtype predominated (67.6%) in the control group. Only 7% of tumours were of the sarcomatoid subtype. The average age of patients in the study group was 57.4 years, thus lower than in the control group (62.8 years). Lung dust analysis showed an increased pulmonary asbestos burden in 94% of all patients; significant differences between the study and control group were not observed. In the majority of the total group pleural effusions were the first symptoms. Therapeutic data were available in fewer than 40% of all cases. Surgical interventions were performed, partly in combination with radiation and chemotherapy and as alternative treatments. Significant deviations in survival time dependent on therapy applied could not be proved. By multivariate analysis (Cox proportional hazards regression model) favourable prognostic factors for long-term survival were epithelioid tumour subtype, comparatively young age (<60 years), and female gender ( P<0.05).

Enhanced effectiveness of last generation antiblastic compounds vs. cisplatin on malignant pleural mesothelioma cell lines

The purpose of this study was to examine the antiproliferative potentialities of a pool of new generation compounds (Paclitaxel, Docetaxel, Gemcitabine, Topotecan, SN-38) together with fenretinide, a synthetic derivative of retinoic acid, in comparison with the current first choice treatment cisplatin molecule, on a pool of human malignant pleural mesothelioma cell lines derived from either bioptic and pleural effusions samples. To evaluate the chemosensitivity features of malignant mesothelioma cells in vitro, we resorted to a rapid and reproducible colorimetric assay, a useful widely recognized tool for preclinical drug screening. In addition, by DNA content analysis and cellular morphologic assessment, we focused on the apoptosis as a potential mechanism of drug activity. The main results clearly indicate that, in all the models of malignant mesothelioma we handled in vitro, each tested antineoplastic agent is more powerful than cisplatin in inhibiting cell proliferation. Moreover, on experimental evidences basis, we can assume that the cytotoxic activity of tested compounds could be related, at least partially, to the drug-induced programmed cell death. This experimental study gives substance to the expected pharmacologic worth of the second generation antineoplastic drugs even if, in order to afford the most satisfactory biopharmacological approach, allowing to bypass the refractoriness to chemotherapy of this highly lethal tumour, further investigations at preclinical level are required.