Management of recurrent malignant pleural effusions: an ever-recurring issue?

The role of microRNA-93 regulating angiopoietin2 in the formation of malignant pleural effusion

The biological roles of miRNAs in the development of malignant pleural effusion (MPE) are unclear. In this study, the miRNA microarray analysis was performed in two different prognosis groups of lung adenocarcinoma patients. Expression profiles of miRNAs in MPEs were identified. With the help of quantification PCR, we confirmed the expression differences of miRNAs and further analyzed their biological functions and relative target genes in vitro. The target gene of miR-93 was estimated by online database, and also, the protein was tested. The target gene and the binding sites of specific miRNA were estimated by online database. The combining capacity of binding sites was verified by luciferase reporter gene assay, and the target gene protein was tested by western blot. We detected 107 miRNAs with expression differences (n = 10) and confirmed significant expression differences in miR-93 and miR-146a in two groups of patients (n = 84). By manipulating miR-93 expression of human lymphatic endothelial cells (HLEC) and human umbilical vein endothelial cells (HUVEC), we discovered that high expression of miR-93 inhibited migration, proliferation, and angiogenesis. And also, miR-93 increased not only apoptosis, but also G1 phase cell block. By using luciferase reporter gene assay and western blot, we confirmed that angiopoietin2 (Ang2) was the target of miR-93. The data showed that miR-93 has an inhibiting effect on pleural effusion. By targeting Ang2, miR-93 regulates angiogenesis and lymphangiogenesis and plays a role in pathogenetic mechanism of MPE. MiR-93/Ang2 may shed light on potential new targets in cancer treatment.

Itraconazole can inhibit malignant pleural effusion by suppressing lymphangiogenesis in mice

BACKGROUND

The presence of malignant pleural effusion (MPE) indicates a poor prognosis in patients with non-small cell lung cancer (NSCLC). Itraconazole has been identified as a potent inhibitor of endothelial cell proliferation that suppresses angiogenesis; however, its role in the suppression of lymphangiogenesis is still unclear. The aim of this study was to investigate the efficacy of itraconazole for MPE and the mechanism of lymphangiogenesis suppression.

METHODS

Lewis lung carcinoma (LLC) cells were injected into the mouse pleural cavity to establish the MPE mouse model, followed by randomization of the mice into three groups. Each mice was injected with either a high dose of itraconazole (25 mg/kg, H-ITCZ), a low dose of itraconazole (8 mg/kg, L-ITCZ), or 50 μL of hydroxypropyl-β-cyclodextrin (130 mg/mL, H-β-C) into the pleural cavity four times every 3 days. The MPE of the mice was collected and measured with a 1 mL syringe. The vascular endothelial growth factor-C (VEGF-C) expression level in the MPE was detected by enzyme-linked immunosorbent assay (ELISA), while the VEGF-C expression and lymphatic micro vessel density (LMVD) in the tumor tissue was observed by immunohistochemistry (IHC) staining.

RESULTS

The number of pleural tumor foci, the volume of pleural effusion, the LMVD and the VEGF-C expression levels in the tumor tissue were significantly reduced in the H-ITCZ-treated group.

CONCLUSIONS

Our results revealed that itraconazole may play an important role in the MPE mice by suppressing lymphangiogenesis, which demonstrated the usefulness of itraconazole in the treatment of MPE.