Upregulation of heme oxygenase-1 expression in gingiva after cyclosporin A treatment.

BACKGROUND: Heme oxygenase (HO)-1 is a stress-inducible protein that confers cytoprotection, but its role in gingiva during cyclosporin A (CsA) therapy is unknown. We used in vivo and in vitro models to investigate the expression of mRNA and protein for HO-1 in gingiva upon CsA treatment. METHODS: Twenty-six male Sprague-Dawley rats were assigned to two groups after the establishment of edentulous ridges. Rats in the CsA group received CsA, 30 mg/kg/day for 4 weeks, whereas control rats received mineral oil only. All rats were killed after 4 weeks, and the edentulous gingivae were excised. mRNA and protein expression of HO-1 in gingivae were determined using reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC), respectively. For the in vitro study, cultured human gingival fibroblasts were harvested after treatment with various concentrations of CsA, and HO-1 mRNA and protein expression were determined using RT-PCR and Western blotting, respectively. RESULTS: Mean gingival HO-1 mRNA expression was greater in the CsA group than in the control animals (P = 0.076). IHC staining for HO-1 protein was significantly greater in the gingivae of CsA-treated rats than in those of the control group. In fibroblast cultures, expression of HO-1 mRNA and protein also increased significantly after CsA treatment. CONCLUSION: CsA upregulates the gingival expression of HO-1, which may exert a cytoprotective effect.

The molecular and clinical verification of therapeutic resistance via the p38 MAPK-Hsp27 axis in lung cancer.

UNLABELLED: Treatment failure followed by relapse and metastasis in patients with non-small cell lung cancer is often the result of acquired resistance to cisplatin-based chemotherapy. A cancer stem cell (CSC)-mediated anti-apoptotic phenomenon is responsible for the development of drug resistance. The underlying molecular mechanism related to cisplatin resistance is still controversial, and a new strategy is needed to counteract cisplatin resistance. We used a nonadhesive culture system to generate drug-resistant spheres (DRSPs) derived from cisplatin-resistant H23 lung cancer cells. The expressions of drug-resistance genes, properties of CSCs, and markers of anti-apoptotic proteins were compared between control cells and DRSPs. DRSPs exhibited upregulation of cisplatin resistance-related genes. Gradual morphological alterations showing epithelial-to-mesenchymal transition phenomenon and increased invasion and migration abilities were seen during induction of DRSPs. Compared with control cells, DRSPs displayed increased CSC and anti-apoptotic properties, greater resistance to cisplatin, and overexpression of p-Hsp27 via activation of p38 MAPK signaling. Knockdown of Hsp27 or p38 decreased cisplatin resistance and increased apoptosis in DRSPs. Clinical studies confirmed that the expression of p-Hsp27 was closely associated with prognosis. Overexpression of p-Hsp27 was usually detected in advanced-stage patients with lung cancer and indicated short survival. SUMMARY: DRSPs were useful for investigating drug resistance and may provide a practical model for studying the crucial role of p-Hsp27 in the p38 MAPK-Hsp27 axis in CSC-mediated cisplatin resistance. Targeting this axis using siRNA Hsp27 may provide a treatment strategy to improve prognosis and prolong survival in lung cancer patients.