Qianming Chen

Nano-structured smart hydrogels with rapid response and high elasticity

Smart hydrogels, or stimuli-responsive hydrogels, are three-dimensional networks composed of crosslinked hydrophilic polymer chains that are able to dramatically change their volume and other properties in response to environmental stimuli such as temperature, pH and certain chemicals. Rapid and significant response to environmental stimuli and high elasticity are critical for the versatility of such smart hydrogels. Here we report the synthesis of smart hydrogels which are rapidly responsive, highly swellable and stretchable, by constructing a nano-structured architecture with activated nanogels as nano-crosslinkers. The nano-structured smart hydrogels show very significant and rapid stimuli-responsive characteristics, as well as highly elastic properties to sustain high compressions, resist slicing and withstand high level of deformation, such as bending, twisting and extensive stretching. Because of the concurrent rapid and significant stimuli-response and high elasticity, these nano-structured smart hydrogels may expand the scope of hydrogel applications, and provide enhanced performance in their applications.

Hippo-independent activation of YAP by the GNAQ uveal melanoma oncogene through a trio-regulated rho GTPase signaling circuitry.

Mutually exclusive activating mutations in the GNAQ and GNA11 oncogenes, encoding heterotrimeric Gαq family members, have been identified in ∼ 83% and ∼ 6% of uveal and skin melanomas, respectively. However, the molecular events underlying these GNAQ-driven malignancies are not yet defined, thus limiting the ability to develop cancer-targeted therapies. Here, we focused on the transcriptional coactivator YAP, a critical component of the Hippo signaling pathway that controls organ size. We found that Gαq stimulates YAP through a Trio-Rho/Rac signaling circuitry promoting actin polymerization, independently of phospholipase Cβ and the canonical Hippo pathway. Furthermore, we show that Gαq promotes the YAP-dependent growth of uveal melanoma cells, thereby identifying YAP as a suitable therapeutic target in uveal melanoma, a GNAQ/GNA11-initiated human malignancy.

NF-κB-dependent cytokines in saliva and serum from patients with oral lichen planus: A study in an ethnic Chinese population

To access the potential roles of NF-kappaB-dependent pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), interleukin-6(IL-6), and interleukin-8(IL-8), in oral lichen planus (OLP), and to explore whether salivary detection of these cytokines is a better monitoring tool than serum for OLP, 30 Chinese patients with OLP and 30 age-sex-matched controls were enrolled in this study. Salivary and serum levels of cytokines were screened by enzyme immunoassay, and both salivary and serum levels of these cytokines were significantly increased in OLP patients in comparison with healthy subjects. Positive statistical correlations existed between these cytokines in serum and saliva. With regards to the subtypes of this illness, only salivary IL-8 levels in erosive form were remarkably inclined than that in reticular form. The results suggest that saliva-based test may provide a more cost-effective adjunctive tool for the detection of pro-inflammatory cytokines in OLP, and salivary IL-8 analysis may be a promising biomarker for OLP severity.

MicroRNA-23a/b and microRNA-27a/b suppress Apaf-1 protein and alleviate hypoxia-induced neuronal apoptosis

Expression of apoptotic protease activating factor-1 (Apaf-1) gradually decreases during brain development, and this decrease is likely responsible for the decreased sensitivity of brain tissue to apoptosis. However, the mechanism by which Apaf-1 expression is decreased remains elusive. In the present study, we found that four microRNAs (miR-23a/b and miR-27a/b) of miR-23a-27a-24 and miR-23b-27b-24 clusters play key roles in modulating the expression of Apaf-1. First, we found that miR-23a/b and miR-27a/b suppressed the expression of Apaf-1 in vitro. Interestingly, the expression of the miR-23-27-24 clusters in the mouse cortex gradually increased in a manner that was inversely correlated with the pattern of Apaf-1 expression. Second, hypoxic injuries during fetal distress caused reduced expression of the miR-23b and miR-27b that was inversely correlated with an elevation of Apaf-1 expression during neuronal apoptosis. Third, we made neuronal-specific transgenic mice and found that overexpressing the miR-23b and miR-27b in mouse neurons inhibited the neuronal apoptosis induced by intrauterine hypoxia. In conclusion, our results demonstrate, in central neural system, that miR-23a/b and miR-27a/b are endogenous inhibitory factors of Apaf-1 expression and regulate the sensitivity of neurons to apoptosis. Our findings may also have implications for the potential target role of microRNAs in the treatment of neuronal apoptosis-related diseases.

Comparative Proteomics Approach to Screening of Potential Diagnostic and Therapeutic Targets for Oral Squamous Cell Carcinoma

This work demonstrates that a comprehensive strategy of proteomics identification combined with further validation and detailed functional analysis should be adopted in the field of cancer biomarker discovery. A comparative proteomics approach was utilized to identify differentially expressed proteins in 10 oral squamous carcinoma samples paired with their corresponding normal tissues. A total of 52 significantly and consistently altered proteins were identified with eight of these being reported for the first time in oral squamous carcinoma. Of the eight newly implicated proteins, RACK1 was chosen for detailed analysis. RACK1 was demonstrated to be up-regulated in cancer at both the mRNA and protein levels. Immunohistochemical examination showed that the enhanced expression of RACK1 was correlated with the severity of the epithelial dysplasia as well as clinical stage, lymph node involvement, and recurrence, which are known indicators of a relatively poor prognosis in oral squamous carcinoma patients. RNA interference specifically targeted to silence RACK1 could initiate apoptosis of oral squamous carcinoma cells. Taken together, the results indicate that RACK1 is up-regulated in oral squamous carcinoma, not only being closely related to cell proliferation and apoptosis but also linked to clinical invasiveness and metastasis in carcinogenesis. The observations suggest that RACK1 may be a potential biomarker for early diagnosis, prognosis, and monitoring in the therapy of oral squamous carcinoma. Further this comprehensive strategy could be used for identifying other differentially expressed proteins that have potential to be candidate biomarkers of oral squamous carcinoma.

Neuroprotective effects of ginsenoside Rb1 on transient cerebral ischemia in rats.

Previous experiments showed that ginsenoside Rb1 (GRb1) reduced infarct and neuronal deficit in rats followed by transient cerebral ischemia. The mechanism of this neuroprotective function is unclear. Here, we tested whether the effect of GRb1 can be achieved through preventing ischemic neuronal death, modulating apoptotic-related genes and affecting glial-derived neurotrophic factor (GDNF) expression in rats subjected to occlusion of the middle cerebral artery. When GRb1(40 mg/kg, i.p.) was administered immediately after reperfusion, the apoptotic cells in the GRb1 group were decreased significantly from 12 to 72 h of reperfusion compared to the ischemia group by TdT-mediated dUTP-biotin nick-end labeling. Immunostaining and Western blotting analysis showed that the expression of GDNF from 3 to 120 h of the GRb1 group was significantly increased compared to the ischemia group, and GDNF expression peaked at 48 h after reperfusion. The enhanced GDNF mRNA in the GRb1 group was not detected by RT-PCR and in situ hybridization compared to the ischemia group, but GDNF mRNA at 48 h after reperfusion was strongly increased in both the ischemia and GRb1 group when compared to other time points. The number of bcl-2-positive cells was significantly increased from 12 to 120 h of reperfusion compared to the ischemia group. However, the number of bax-positive cells in the GRb1 group was significantly declined compared to the ischemia group. In the GRb1 group, the number of neuronal apoptosis inhibitory protein-positive cells from 12 to 120 h after reperfusion was evidently higher than that in the ischemia group. Therefore, ginsenoside Rb1 prevents ischemic neuronal death induced by transient cerebral ischemia, and this mechanism of which is related to increase the expression of the antiapoptotic genes and modulate the expression of GDNF.

mTOR Co-Targeting in Cetuximab Resistance in Head and Neck Cancers Harboring PIK3CA and RAS Mutations

Background Cetuximab, a monoclonal blocking antibody against the epidermal growth factor receptor EGFR, has been approved for the treatment of squamous cell carcinomas of the head and neck (HNSCC). However, only few patients display long-term responses, prompting the search for cetuximab resistance mechanisms and new therapeutic options enhancing cetuximab effectiveness. Methods Cetuximab-sensitive HNSCC cells were retro-engineered to express PIK3CA and RAS oncogenes. These cells and HNSCC cells harboring endogenous PIK3CA and RAS oncogenes were xenografted into mice (n = 10 per group) and studied for their biochemical, antitumor, antiangiogenic, and antilymphangiogenic responses to cetuximab and mTOR targeting agents. All P values are two-sided. Results Cetuximab treatment of PIK3CA- and RAS-expressing HNSCC xenografts promoted an initial antitumor response, but all tumors relapsed within few weeks. In these tumors, cetuximab did not decrease the activity of mTOR, a downstream signaling target of EGFR, PIK3CA, and RAS. The combined administration of cetuximab and mTOR inhibitors exerted a remarkably increased antitumor activity, particularly in HNSCC cells that are resistant to cetuximab as a single agent. Indeed, cotargeting mTOR together with cetuximab caused a rapid tumor collapse of both PIK3CA- and RAS-expressing HNSCC xenografts (P < .001), concomitant with reduced proliferation (P < .001) and lymphangiogenesis (P < .001). Conclusion The presence of PIK3CA and RAS mutations and other alterations affecting the mTOR pathway activity in HNSCC could be exploited to predict the potential resistance to cetuximab, and to select the patients that may benefit the most from the concomitant administration of cetuximab and PI3K and/or mTOR inhibitors as a precision molecular therapeutic option for HNSCC patients.

Oral cancer overexpressed 1 (ORAOV1): A regulator for the cell growth and tumor angiogenesis in oral squamous cell carcinoma

Oral Cancer Overexpressed 1 (ORAOV1) is a novel gene locating at chromosome band 11q13. Recent studies have suggested its role as a candidate oncogene in oral squamous cell carcinoma (OSCC) and its prognostic value for patients with OSCC. Till now, the detailed function of ORAOV1 in OSCC has remained undefined. In this study, we have investigated the role of ORAOV1 in OSCC tumorigenesis by down‐regulating its expression. Small interfering RNA (siRNA) has been applied to inhibit the expression of ORAOV1 in OSCC cells. We found that the OSCC cells with reduced ORAOV1 showed retarded cell growth in vitro and displayed inhibition in both tumor growth and tumor angiogenesis in vivo. Further analyses reveal that the retarded cell growth is associated with an increase in apoptosis involving the activation of caspase 3‐dependent pathway and a cell cycle arrest at the S‐phase with a downregulation of cyclin A, cyclin B1 and cdc2. The suppressed tumor growth in vivo may be attributed to synergistic effect between inhibition in cell growth and suppression of tumor angiogenesis. The latter is most likely because of a suppression of VEGF. Taken together, we demonstrate that ORAOV1 plays pivotal roles in the growth and angiogenesis of OSCC. Thus, ORAOV1 may be a novel target that could be explored to develop therapeutic strategy in OSCC management.

RACK1, an excellent predictor for poor clinical outcome in oral squamous carcinoma, similar to Ki67

PURPOSE The aim of this study was to evaluate the significance of RACK1 in predicting outcome for patients with oral squamous cell carcinoma (OSCC) compared with Ki67. METHODS The expression of both RACK1 and Ki67 in 130 patients with OSCC was illustrated by using immunohistochemistry assay. Multiple logistic regression and Pearsons correlation coefficient were used. Recurrence versus non-recurrence of the malignant lesions was considered as the surrogate for clinical outcome of patients. RESULTS Multivariable logistic regression showed that the elevated RACK1 immunostaining was a factor having great influence on OSCC prognosis. RACK1 staining was strongly related to that of Ki67. The area under the receiver operating characteristic curve for both biomarkers in predicting recurrence was 0.72 and 0.70 respectively, indicating an excellent discrimination for RACK1 as well as for Ki67. CONCLUSIONS These data indicate that increased RACK1 expression is an important outcome predictor for OSCC compared with Ki67.

IFN-Gamma and IL-4 in Saliva of Patients with Oral Lichen Planus: A Study in an Ethnic Chinese Population

Interferon-gamma (IFN-γ) and interleukin-4 (IL-4) represent T helper 1 (Th1) and T helper 2 (Th2) cytokines involved in oral lichen planus (OLP), respectively. This study was to investigate the expression profile of IFN-γ and IL-4 in saliva of OLP patients. Seventy-nine ethnic Chinese patients with OLP were recruited for this study, together with 41 age–sex-matched healthy volunteers served as control group. IFN-γ and IL-4 levels in whole unstimulated saliva were screened by enzyme linked immunosorbent assay. OLP patient showed a low-level IFN-γ but high-level IL-4 expression profile in saliva, with a lower ratio of salivary IFN-γ/IL-4 compared to healthy controls. With regards to subtypes, salivary IL-4 level in erythematous/ulcerative group was significantly higher than that in reticular group. Imbalance of Th1/Th2 cytokines with Th2-predominant profile in saliva may be involved in OLP. Salivary IL-4 level may be a fine biomarker reflecting the severity of OLP.