Dunfang Zhang

Receptor for activated C kinase 1 (RACK1): a regulator for migration and invasion in oral squamous cell carcinoma cells

PurposeReceptor of activated protein kinase C 1 (RACK1) has been identified as an anchoring or adaptor protein in multiple intracellular signal transduction pathways. Our previous study has showed that the expression of RACK1 was paralleled with proliferation and correlated with metastasis and clinical outcome. However, the underlined mechanism has not been uncovered.Materials and methodsWe first selected a most effective siRNA among three siRNAs (siRNA-1, siRNA-2 and siRNA-3) targeting different regions in the RACK1 mRNA and re-evaluated the anticancer effect of RACK1 silencing on HSC-3 and Cal-27 cell lines by cell growth inhibition. And then, we investigated whether knockdown of RACK1 could inhibit cell adhesion, migration and invasion in these two cell lines. To further understand the molecular mechanism of RACK1 in these processes, the expressions of EGFR, pEGFR, HER2, MMP-2 and MMP-9 were detected by western blot.ResultsWe verified that the silence of RACK1 gene in two OSCC cell lines could not only inhibit cell proliferation but also decrease the invasion, migration and adhesion capability of the tumor cells. Further, western blot analysis deduced that it might be related to the decrease in protein expression of EGFR, pEGFR, HER2, MMP-2 and MMP-9.ConclusionOur results clearly showed the significance of RACK1-induced OSCC cell migration, invasion and adhesion, which could explain the underlined mechanism of the effect of the gene on metastasis and clinical outcome. Also, our results confirmed its role to be a prognostic indicator and a promising drug target for OSCC cell metastasis.

Biodegradable Thermosensitive Hydrogel for SAHA and DDP Delivery: Therapeutic Effects on Oral Squamous Cell Carcinoma Xenografts

Background OSCC is one of the most common malignancies and numerous clinical agents currently applied in combinative chemotherapy. Here we reported a novel therapeutic strategy, SAHA and DDP-loaded PECE (SAHA-DDP/PECE), can improve the therapeutic effects of intratumorally chemotherapy on OSCC cell xenografts. Objective/Purpose The objective of this study was to evaluate the therapeutic efficacy of the SAHA-DDP/PECE in situ controlled drug delivery system on OSCC cell xenografts. Methods A biodegradable and thermosensitive hydrogel was successfully developed to load SAHA and DDP. Tumor-beared mice were intratumorally administered with SAHA-DDP/PECE at 50 mg/kg (SAHA) +2 mg/kg (DDP) in 100 ul PECE hydrogel every two weeks, SAHA-DDP at 50 mg/kg(SAHA) +2 mg/kg(DDP) in NS, 2 mg/kg DDP solution, 50 mg/kg SAHA solution, equal volume of PECE hydrogel, or equal volume of NS on the same schedule, respectively. The antineoplastic actions of SAHA and DDP alone and in combination were evaluated using the determination of tumor volume, immunohistochemistry, western blot, and TUNEL analysis. Results The hydrogel system was a free-flowing sol at 10°C, become gel at body temperature, and could sustain more than 14 days in situ. SAHA-DDP/PECE was subsequently injected into tumor OSCC tumor-beared mice. The results demonstrated that such a strategy as this allows the carrier system to show a sustained release of SAHA and DDP in vivo, and could improved therapeutic effects compared with a simple additive therapeutic effect of SAHA and DDP on mouse model. Conclusions Our research indicated that the novel SAHA-DDP/PECE system based on biodegradable PECE copolymer enhanced the therapeutic effects and could diminished the side effects of SAHA/DDP. The present work might be of great importance to the further exploration of the potential application of SAHA/DDP-hydrogel controlled drug release system in the treatment of OSCC.

The Activation of NF-κB in Infiltrated Mononuclear Cells Negatively Correlates with Treg Cell Frequency in Oral Lichen Planus.

Oral lichen planus (OLP) is a T cell-mediated chronic inflammatory mucosal disease with persistent accumulation of T cells in the lamina propria. Nuclear factor-kappa B (NF-κB) is a major regulator of immune responses, and NF-κB-dependent cytokines and pro-inflammatory mediators can be detected in higher levels in the saliva and serum from patients with OLP. CD4+CD25+Foxp3+ regulatory T (Treg) cells play an important role in the prevention of autoimmune pathology by regulating the immune response. To explore the correlation between NF-κB p65 activation and accumulation of Treg cells in patients with OLP, 40 ethnic Chinese patients with OLP and 10 healthy volunteers were recruited. The nuclear expression of NF-κB p65 in infiltrated mononuclear cells and Treg cells in the OLP lesion and the normal oral mucosa (NOM) was analyzed by immunohistochemistry assay. Our results showed that both the nuclear expression of NF-κB p65 and the number of Foxp3+ Treg were higher in the OLP lesions. Furthermore, the frequency of Treg cells was negatively correlated with NF-κB nuclear expression in subepithelial lymphocytic infiltrate of the OLP lesion. This finding provides a new insight into the pathogenesis of OLP and may contribute to novel therapeutic strategies for the treatment of OLP by modulating the immune system.

Associations between proteasomal activator PA28γ and outcome of oral squamous cell carcinoma: Evidence from cohort studies and functional analyses.

Summary Background PA28γ was suggested to play a role in malignant progression. This paper aimed to investigate the association between PA28γ and the prognosis of oral squamous cell carcinoma (OSCC) in cohort studies. Methods The PA28γ expression level was assessed by immunohistochemistry in a total of 368 OSCC patients from three independent cohorts. The Cox proportional hazards regression model was used to determine multivariate hazard ratios for Overall Survival (OS). Model discrimination was measured using C Statistic. Additionally, OS was analyzed in Head Neck Squamous Cell Carcinoma (HNSCC) patients from The Cancer Genome Atlas (TCGA) data set. Functional analyses were conducted both in-vitro and in-vivo. Findings The median follow-up times of patients in the three studies were 60, 52, and 51 months. High expression of PA28γ was identified in tumors from 179 of 368 patients (48.6%). Compared with low expression, high expression of PA28γ was strongly associated with worse OS, with relative risks of 5.14 (95% CI, 2.51–10.5; P < 0.001), 2.82 (95% CI, 1.73–4.61; P < 0.001), and 3.85 (95% CI, 1.59–9.37; P = 0.003). PA28γ expression was also associated with disease-free survival in all three cohorts (P < 0.005). These findings are consistent with TCGA HNSCC data (P < 0.006). The prediction of all-cause mortality was significantly improved when PA28γ was added to the traditional clinical factors (Model 3, C statistic value: 0.78 VS 0.73, P = 0.016). In functional analyses, we found that PA28γ silencing dramatically inhibited the growth, proliferation and mobility of OSCC cells in vitro and reduced tumor growth and angiogenesis in tumor-bearing mice. Interpretation PA28γ overexpression is associated with adverse prognosis in patients with OSCC. The aberrant expression of PA28γ may contribute to the pathogenesis and progression of OSCC. Research in context OSCC is one of the most common HNSCC, which have a high lethally rate. However, few prognostic markers have been applied in the clinical practice. We found that PA28γ in OSCC tumor tissues were significantly high expression than those in normal tissues. As the results of the three cohorts from two independent research centers and from an additional validation cohort from a US population in the TCGA dataset, we demonstrate PA28γ is a good predictor of the risk of death in OSCC. Meanwhile, we demonstrate PA28γ have a potential role in OSCC tumorigenesis.

Regulatory T cells in oral squamous cell carcinoma

Regulatory T cells (Tregs) play a critical role in modulating and maintaining immune homeostasis and tolerance. They accumulate in many types of tumors and play a critical role in tumor evasion of immune surveillance. Oral cancer is characterized by an increase in the number of infiltrating Tregs; however, the significance of this increase on the prognosis of oral cancer is controversial. This review focuses on the function of Tregs in oral squamous cell carcinoma and its implications on prognosis. We also discuss potential therapeutic strategies aimed at Tregs modification in oral SCC.

Overexpression of proteasomal activator PA28α serves as a prognostic factor in oral squamous cell carcinoma

BackgroundDespite recent advances in oral squamous cell carcinoma (OSCC) diagnosis and therapy, disease recurrence remains common and is strongly associated with mortality. It is therefore critical to identify new targets for both treatment and diagnostic purposes. We aimed at investigating the role of PA28α, a proteasomal activator in OSCC.MethodsThe expression of PA28α was examined in a panel of OSCC cell lines and tissues, associated with oncomine analysis. In a large OSCC patient cohort, the prognostic value of PA28α expression was evaluated. Primary clinical end points were recurrence-free and overall survival rate. Functional involvement of PA28α in OSCC was examined in both in vitro and in vivo models upon specific siRNA knockdown.ResultsPA28α was found to be overexpressed in OSCC cell lines and tumor tissues. High expression of PA28α was significantly associated with recurrence and poorer overall survival. Specific knockdown of PA28α inhibited OSCC cell proliferation, migration, invasion in vitro and reduced the growth of OSCC xenografts in vivo. Multivariate Cox regression analyses revealed PA28α as independent prognostic predictors.ConclusionsThese results suggest that PA28α is involved in OSCC oncogenesis and may serve as a potential prognostic factor.

Screening diagnostic biomarkers of OSCC via an LCM-based proteomic approach

The current standard for the diagnosis of oral squamous cell carcinoma (OSCC) is based on the histologic examination of hematoxylin and eosin-stained sections; however, the discrimination among normal tissue, pre‑cancerous lesions and cancerous lesions can be difficult. The aim of the present study was to identify proteins with diagnostic significance in differentiating or predicting oral mucosal carcinogenesis. Proteomic profiling based on the laser capture microdissection of formalin-fixed, paraffin-embedded samples was performed, followed by liquid chromatography-tandem mass spectrometry (LC/MS) analysis. Immunohistochemistry (IHC) was used to evaluate the results. IHC of cytokeratins (CKs) was performed in neck dissection treatment cases. The accuracy rate and 95% confidence intervals (CIs) were used to evaluate the value of CKs as biomarkers of OSCC. A lymph node metastasis mouse model was used to validate the selected biomarkers. Among the proteins identified using LC/MS, several CKs exhibited significant differential expression patterns between the cancerous and para-cancerous tissues. The IHC results showed that negative staining of CK4 and CK10/13 distinguished cancerous from para-cancerous tissues with an accuracy of 90% (95% CI, 0.68-0.99) and 75% (95% CI, 0.51-0.91), respectively. Furthermore, the positive staining of CK14 and CK17 clearly distinguished cancerous from para-cancerous lesions with an accuracy of 100% (95% CI, 83-100%) and 90% (95% CI, 0.68-0.99), respectively. There was also CK14-positive staining in micro-metastases of lymph nodes in the clinical samples and in an animal model.

Adoptive Induced Antigen-Specific Treg Cells Reverse Inflammation in Collagen-Induced Arthritis Mouse Model

Rheumatoid arthritis (RA) is a systemic autoimmune disease that may cause bone damage and worsening disability. Manipulating antigen-specific Treg cells is a promising approach to treat autoimmune disease since the immune suppressive function of Treg cells has the feature of antigen specificity which could avoid overall immune suppression. It has been known that the function of Treg cells is impaired in RA, and adoptive transfer of Treg cells is effective in suppressing RA. Here, we designed a new approach to generate antigen-specific Treg cells by culturing CD4+ T cells from mice with RA onset, and we also proved that the adoptive transfer of these antigen-specific Treg cells reversed the collagen-induced arthritis (CIA) progression by suppressing the key inflammatory cytokine TNF-α. Further analysis showed that the transferred Treg cells were stable in vivo. These findings suggest this novel approach may have clinical applications for treatment of autoimmunity, including RA and other autoimmune disorders.