Zoledronic acid overcomes chemoresistance and immunosuppression of malignant mesothelioma

The human malignant mesothelioma (HMM) is characterized by a chemoresistant and immunosuppressive phenotype. An effective strategy to restore chemosensitivity and immune reactivity against HMM is lacking. We investigated whether the use of zoledronic acid is an effective chemo-immunosensitizing strategy.

We compared primary HMM samples with non-transformed mesothelial cells.

HMM cells had higher rate of cholesterol and isoprenoid synthesis, constitutive activation of Ras/extracellular signal-regulated kinase1/2 (ERK1/2)/hypoxia inducible factor-1α (HIF-1α) pathway and up-regulation of the drug efflux transporter P-glycoprotein (Pgp). By decreasing the isoprenoid supply, zoledronic acid down-regulated the Ras/ERK1/2/HIF-1α/Pgp axis and chemosensitized the HMM cells to Pgp substrates. The HMM cells also produced higher amounts of kynurenine, decreased the proliferation of T-lymphocytes and expanded the number of T-regulatory (Treg) cells. Kynurenine synthesis was due to the transcription of the indoleamine 1,2 dioxygenase (IDO) enzyme, consequent to the activation of the signal transducer and activator of transcription-3 (STAT3). By reducing the activity of the Ras/ERK1/2/STAT3/IDO axis, zoledronic acid lowered the kyurenine synthesis and the expansion of Treg cells, and increased the proliferation of T-lymphocytes.

Thanks to its ability to decrease Ras/ERK1/2 activity, which is responsible for both Pgp-mediated chemoresistance and IDO-mediated immunosuppression, zoledronic acid is an effective chemo-immunosensitizing agent in HMM cells.

ERCC1 as a biological marker guiding management in malignant pleural mesothelioma

BACKGROUND

To determine prognostic value of excision repair cross-complementation 1 (ERCC1) in patients with malignant pleural mesothelioma (MPM).

MATERIALS AND METHODS

The study included 60 patients with MPM who were diagnosed and treated in the Radiation Oncology Department of Kayseri Teaching Hospital and Medical Oncology Department of Erciyes University, Medicine School between 2005 and 2013. By using immunohistochemical methods, ERCC1 expression in biopsy specimens was evaluated. We retrospectively assessed whether there is a correlation between ERCC1 and response to anti-neoplastic therapy or survival.

RESULTS

There were 50 men and 10 women with median age of 62 years (range: 39-83). Histological type was epithelial mesothelioma in the majority of the cases (85%), most commonly presenting in stage four. Of the cases, 20 (33%) received radiotherapy, 60 (%100) received first-line chemotherapy and 15 (%25) received second-line chemotherapy. In the assessment after therapy, it was found that there was partial response in 12 cases (20%), stable disease in 19 cases (31.4%) and progression in 25 cases (41.7%). ERCC1 was positive in 43% of the cases. Mean OS was 11.7 months and mean DFS was 9.5 months in ERCC1-positive cases regardless of therapy, while they were 19.2 months and 17.1 months in ERCC1-negative cases, respectively. The difference was found to be significant (p<0.05). In univariate analysis, stage, comorbidity, response to treatment and ERCC1 expression were found to be significantly associated with OS (p=0.083; p=0.043; p=0.041; p=0.050). In multivariate analysis, response to treatment remained to be significant for OS (p=0.005). In univariate and multivariate analyses, response to treatment and ERCC1 were found to be significantly associated with DFS (p=0.049; p=0.041).

CONCLUSIONS

ERCC1 was identified as poor prognostic factor in patients with MPM.

Clinical study on carboplatin for treating pediatric patients with Wilms tumors

This analysis was conducted to evaluate the efficacy and safety of carboplatin based chemotherapy in treating pediatric patients with Wilms tumors.

METHODS

Clinical studies evaluating the efficacy and safety of carboplatin based regimens on response and safety for pediatric patients with Wilms tumors were identified using a predefined search strategy. Pooled response rates (RRs) of treatment were calculated.

RESULTS

In carboplatin based regimens, 4 clinical studies which including 127 patients with advanced Wilms tumors were considered eligible for inclusion. With this carboplatin based chemotherapy, 2 clinical studies included carboplatin, ifosfamide and etoposide. Systemic analysis suggested that, in all patients, the pooled PR was 64.5% (82/127) in carboplatin based regimens. Thrombocytopenia and leukocytopenia were the main side effects. No grade III or IV renal or liver toxicity was observed. No treatment related death occurred with carboplatin based treatment.

CONCLUSION

This systemic analysis suggests that carboplatin based regimens are associated with a reasonable response rate and accepted toxicities for treating pediatric patients with Wilms tumors.