Silencing of FANCD2 enhances the radiosensitivity of metastatic cervical lymph node-derived head and neck squamous cell carcinoma HSC-4 cells

Abstract

Abstract. Fanconi anemia complementation group D2 (FANCD2) is involved in the key steps of the Fanconi anemia (FA) pathway, which plays a role in the repair of DNA crosslink damage. However, the role of FANCD2 during radiotherapy for head and neck squamous cell carcinoma (HNSCC) is unclear. In this study, the HNSCC cell line HSC-4 was used. Western blotting was used to evaluate the expression of the FANCD2 in HSC-4 cells. We investigated the impact of FANCD2 on the radiosensitivity of HSC-4 cells in vitro and in vivo. TUNEL, western blotting and immunohistochemistry were used to analyze the apoptosis and proteins involved in apoptosisrelated pathways after radiotherapy to investigate the relevant mechanism. The present study showed that shRNA interference could effectively and stably silence FANCD2 expression in HSC-4 cells. In vitro, the silencing of FANCD2 inhibited cell proliferation, decreased the survival rate, increased apoptosis and induced S phase arrest in HSC-4 cells after radiotherapy. In vivo, the silencing of FANCD2 could prolong the tumor-forming time and slow tumor growth. In addition, the tumor volume was significantly reduced, the weight was deceased, and the tumor inhibition rate was increased after radiotherapy. TUNEL showed that the silencing of FANCD2 significantly increased apoptosis in HSC-4 cells induced by radiotherapy. Both in vitro and in vivo esperiments revealed that the expression of the Bax and p-p38 proteins in HSC-4 cells, in which FANCD2 had been silenced, was increased after radiotherapy, whereas the expression of the p38 and Bcl2 proteins was decreased. Our results suggested that the silencing of FANCD2 enhanced the radiosensitivity of HSC-4 cells, and its mechanism involves the activation of the p38 MAPK signaling pathway and the regulation of the expression of Bax and Bcl2 proteins. This study provides a novel candidate target for HNSCC therapy.

FANCD2 knockdown with shRNA interference enhances the ionizing radiation sensitivity of nasopharyngeal carcinoma CNE-2 cells

“…Each xenograft tumor was aliquoted into two portions for subsequent experiments. The animal experiments were performed according to methods described in previous experiments [24].…”

Solid Lipid Nanoparticles Enhanced the Neuroprotective Role of Curcumin against Epilepsy through Activation of Bcl-2 Family and P38 MAPK Pathways

“…Meanwhile, P38 mitogen-activated protein kinase (MAPK) is a member of the highly conserved threonine/serine MAPK family, acting as signal transduction mediators and involved in apoptosis, cell differentiation, and cell cycle. 45 Activation of P38 MAPK can increase the ratio of Bax and Bcl2, which leads to mitochondrial membrane permeability and finally results in the release of cytochrome C, activation of caspases, and apoptosis. 46 Reducing P38 phosphorylation level and upregulating Bcl2 can protect brain against ischemia/ reperfusion induced brain injury.…”

“…As mentioned above, Bcl2 family plays a major role in regulation of apoptosis. Meanwhile, P38 mitogen-activated protein kinase (MAPK) is a member of the highly conserved threonine/serine MAPK family, acting as signal transduction mediators and involved in apoptosis, cell differentiation, and cell cycle . Activation of P38 MAPK can increase the ratio of Bax and Bcl2, which leads to mitochondrial membrane permeability and finally results in the release of cytochrome C, activation of caspases, and apoptosis .…”

“…C57 mice aged 8−9 weeks were separated into two group receiving Cur or Cur-SLNs intraperitoneally at a Cur dose of 20 mg/kg. Mice brains were sampled at predetermined time points (5,15,30,45,60,120,240, and 360 min after treatments). HPLC (Agilent, CA, USA) was used to detect drug concentrations in brains.…”

“…Immunofluorescence. Prefixed neurons and15 μm thick frozen sections were blocked for 45 TUNEL Staining. TUNEL is a histochemical marker of apoptotic cell death.…”