Rui-n Li

Curcumin as therapeutics for the treatment of head and neck squamous cell carcinoma by activating SIRT1.

SIRT1 is one of seven mammalian homologs of Sir2 that catalyzes NAD+-dependent protein deacetylation. The aim of the present study is to explore the effect of SIRT1 small molecule activator on the anticancer activity and the underlying mechanism. We examined the anticancer activity of a novel oral agent, curcumin, which is the principal active ingredient of the traditional Chinese herb Curcuma Longa. Treatment of FaDu and Cal27 cells with curcumin inhibited growth and induced apoptosis. Mechanistic studies showed that anticancer activity of curcumin is associated with decrease in migration of HNSCC and associated angiogenesis through activating of intrinsic apoptotic pathway (caspase-9) and extrinsic apoptotic pathway (caspase-8). Our data demonstrating that anticancer activity of curcumin is linked to the activation of the ATM/CHK2 pathway and the inhibition of nuclear factor-κB. Finally, increasing SIRT1 through small molecule activator curcumin has shown beneficial effects in xenograft mouse model, indicating that SIRT1 may represent an attractive therapeutic target. Our studies provide the preclinical rationale for novel therapeutics targeting SIRT1 in HNSCC.

Curcumin induces G2/M cell cycle arrest and apoptosis of head and neck squamous cell carcinoma in vitro and in vivo through ATM/Chk2/p53-dependent pathway

Studies have demonstrated that curcumin (CUR) exerts its tumor suppressor function in a variety of human cancers including head and neck squamous cell carcinoma (HNSCC). However, the exact underlying molecular mechanisms remain obscure. Here, we aim to test whether CUR affects ATM/Chk2/p53 signaling pathway, leading to the induction of cell cycle arrest, inhibition of angiogenesis of HNSCC in vitro and in vivo. To this end, we conducted multiple methods such as MTT assay, Invasion assay, Flow cytometry, Western blotting, RT-PCR, and transfection to explore the functions and molecular insights of CUR in HNSCC. We observed that CUR significantly induced apoptosis and cell cycle arrest, inhibited angiogenesis in HNSCC. Mechanistically, we demonstrated that CUR markedly up-regulated ATM expression and subsequently down-regulated HIF-1α expression. Blockage of ATM production totally reversed CUR induced cell cycle arrest as well as anti-angiogenesis in HNSCC. Moreover, our results demonstrated that CUR exerts its antitumor activity through targeting ATM/Chk2/p53 signal pathway. In addition, the results of xenograft experiments in mice were highly consistent with in vitro studies. Collectively, our findings suggest that targeting ATM/Chk2/p53 signal pathway by CUR could be a promising therapeutic approach for HNSCC prevention and therapy.Studies have demonstrated that curcumin (CUR) exerts its tumor suppressor function in a variety of human cancers including head and neck squamous cell carcinoma (HNSCC). However, the exact underlying molecular mechanisms remain obscure. Here, we aim to test whether CUR affects ATM/Chk2/p53 signaling pathway, leading to the induction of cell cycle arrest, inhibition of angiogenesis of HNSCC in vitro and in vivo. To this end, we conducted multiple methods such as MTT assay, Invasion assay, Flow cytometry, Western blotting, RT-PCR, and transfection to explore the functions and molecular insights of CUR in HNSCC. We observed that CUR significantly induced apoptosis and cell cycle arrest, inhibited angiogenesis in HNSCC. Mechanistically, we demonstrated that CUR markedly up-regulated ATM expression and subsequently down-regulated HIF-1α expression. Blockage of ATM production totally reversed CUR induced cell cycle arrest as well as anti-angiogenesis in HNSCC. Moreover, our results demonstrated that CUR exerts its antitumor activity through targeting ATM/Chk2/p53 signal pathway. In addition, the results of xenograft experiments in mice were highly consistent with in vitro studies. Collectively, our findings suggest that targeting ATM/Chk2/p53 signal pathway by CUR could be a promising therapeutic approach for HNSCC prevention and therapy.

ASSA14-05-01 Therapeutic Ultrasound Augments Postnatal Neovascularization in Mice Model of Hindlimb Ischemia

Background Therapeutic ultrasound (TUS) has been proposed as a potential strategy to accelerate proliferation and regeneration to the damaged tissue. However, the underline mechanism remains modest clarified. The purpose of this study was to determine the mechanism of TUS on ischemia-induced angiogenesis using mice model of hindlimb ischemia. Methods and results Hindlimb ischemia was induced by unilateral femoral artery resection using 8–12 week-old male C57BL6 mice. External TUS (1.0 MHz, 0.3W/cm2) was then performed for 9 min/day. At postoperative day 14, decreased prevalence of gangrene, increased capillary density and skin temperature ratio between ischaemic/normal extremities were observed in TUS-treated mice. Moreover, the levels of nitric oxide (NO) expression, endothelial nitric oxide synthase (eNOS) and Akt phosphorylation contained in the ischaemic muscles were increased in response to TUS. In vitro, TUS interrupted the process of hypoxia-induced apoptosis and contributed to the tube-formative and proliferative capacities of human umbilical vein endothelial cells. TUS increased the level of NO in the conditioned media, as well as the eNOS and Akt phosphorylation in the cell lysate. Finally, administration of PI3K inhibitor LY294002 and NG-Nitro-L-arginine Methyl Ester (L-NAME) could block these TUS-mediated angiogenic benefits. Conclusions In conclusion, the present study indicates that external ultrasound exposure contributes to ischemia-induced neovascularization through promoting endothelial functions via Akt-eNOS signal pathway.

ASSA14-15-01 Angiogenesis effect of therapeutic ultrasound on ischaemic hind limb in mice

Background Therapeutic ultrasound (TUS) has been proposed as a potential strategy for therapeutic revascularisation. However, the specific mechanism remains to be explored in detail. The purpose of this study was to determine the mechanism of TUS on ischaemic angiogenesis in mice with acute ischaemic hind limb and proliferation, migration, tube formation and potential signalling pathways of human umbilical vein endothelial cells (HUVECs). Methods TUS was set by a combination of various ultrasound-related variables: frequency of 1.0 MHz; intensity of 0.3 W/cm2; exposure time of 3, 6, or 9 min. We stimulated the HUVECs in culture daily with TUS for 3 days. The effects of therapeutic ultrasound on HUVECs proliferation were evaluated using the CCK-8 assay. Cell migration was assayed by scratch test. Angiogenesis was observed by tube formation assay. The potential involvement of PI3K-Akt-eNOS signalling pathways was explored using selective chemical inhibitor or Western-blot analysis. Left femoral artery ligation was used to establish the model of acute hind limb ischaemic in mice (C57BL/6J male mice, 18–22 g, 2–3 months old), TUS was exposed subcutaneously once everyday for 14 days. The mice were randomly divided into four experimental groups: sham operated group; TUS 3 min group; TUS 6 min group and TUS 9 min group. The experiment was carried out on the 1st and14th after ligation. To determine whether TUS affected the angiogenesis activity of mice with ischaemic hind limb, we measured temperature of hind limb by using infrared thermometer, and microvessel density (MVD) was determined by CD31 staining. Results The results show that proliferation, migration and tube formation in HUVECs could be promoted by TUS at exposure time of 9 min, and inhibited by NG-Nitro-L-arginine Methyl Ester (L-NAME). eNOS and p-eNOS expression increased significantly when TUS 9 min was added, but could be attenuated by L-NAME. p-Akt expression augmented by TUS at exposure time of 9 min, but could be inhibited by LY294002. Compared to the temperature of hind limb, the group of TUS 9 min at the 14th was increased, while TUS 6 min group increased, but only TUS 9 min was there a significant difference. Except that, the MVD was promoted in TUS 9 min group significantly. Conclusions In conclusion, the present study indicates that 9 min of exposure to TUS promote angiogenesis among ischaemic hind limb in mice and that this process is mediated through the PI3K-Akt-eNOS signal pathway in ECs.

ASSA14-03-01 Pulsed Electromagnetic Field Improves Postnatal Neovascularization in Response to Hindlimb Ischemia

Background Pulsed electromagnetic fields (PEMF) have been shown to accelerate proliferation and regeneration to the damaged tissue, but its mechanism remains unclear. Here, we examine whether PEMF therapy improves postnatal neovascularization using murine model of hindlimb ischemia, and investigate the underlying cellular/molecular mechanisms. Methods and Results Hindlimb ischemia was induced by unilateral femoral artery resection using 6–8 week-old male C57BL6 mice. PEMF therapy (8 min/cycle, 30 ± 3 Hz, 5 mT) was then performed 4 cycles/day. At postoperative day 21, accelerated wound healing, decreased prevalence of gangrene and increased capillary density were observed among the PEMF-exposed mice. Moreover, the levels of vascular endothelial growth factor (VEGF) expression, endothelial nitric oxide synthase (eNOS) and Akt phosphorylation contained in the ischaemic muscles were increased in response to PEMF therapy. In vitro , PEMF interrupted the process of hypoxia-induced apoptosis and contributed to the tube-formative and proliferative capacities of human umbilical vein endothelial cells. PEMF exposure increased the level of VEGF in the conditioned media, as well as the eNOS and Akt phosphorylation in the cell lysate, and these PEMF-mediated angiogenic benefits could be blocked after PI3K inhibitor was administrated. Conclusions In conclusion, Our data indicated that PEMF enhanced ischemia-mediated angiogenesis, through up-regulating VEGF expression and activating the PI3K-Akt-eNOS pathway. Therefore, PEMF may be valuable for the treatment of the patients with critical limb ischemia.