Role of c-Met in the progression of human oral squamous cell carcinoma and its potential as a therapeutic target

Mesenchymal-epithelial transition factor (c-Met) is the only high affinity receptor for hepatocyte growth factor (HGF), and is frequently activated in many human cancers. However, little is known about the role of the HGF/c-Met signaling pathway in the progression of human oral squamous cell carcinoma (OSCC). This study evaluated the role of the HGF/c-Met signaling pathway in the progression of human OSCC. We found that the expression of c-Met was significantly increased in human OSCC tissues than in normal mucosa adjacent to the tumor (P<0.05), but was not correlated with clinicopathological parameters. Additionally, the selective c-Met inhibitor JNJ was found to inhibit cell viability and migration and promote apoptosis in OSCC cell lines, and also blocked the activation AKT, ERK1/2, and NF-κB p65; thus, suggesting that HGF/c-Met signaling may play an important role in the tumorigenic properties of OSCC cells via the AKT, ERK1/2, and NF-κB pathways. Collectively, these results indicated that HGF/c-Met signaling may serve essential roles in the progression of human OSCC, and may thus be a basis for the development of novel therapeutic approaches in the treatment of OSCC.

Growth differentiation factor 15 promotes blood vessel growth by stimulating cell cycle progression in repair of critical-sized calvarial defect

Repair of large bone defects remains a challenge for surgeons, tissue engineering represents a promising approach. However, the use of this technique is limited by delayed vascularization in central regions of the scaffold. Growth differentiation factor 15(GDF15) has recently been reported to be a potential angiogenic cytokine and has an ability to promote the proliferation of human umbilical vein endothelial cells(HUVECs). Whether it can be applied for promoting vascularized bone regeneration is still unknown. In this study, we demonstrated that GDF15 augmented the expression of cyclins D1 and E, induced Rb phosphorylation and E2F-1 nuclear translocation, as well as increased HUVECs proliferation. Furthermore, we also observed that GDF15 promoted the formation of functional vessels at an artificially-induced angiogenic site, and remarkably improved the healing in the repair of critical-sized calvarial defects. Our results confirm the essential role of GDF15 in angiogenesis and suggest its potential beneficial use in regenerative medicine.

A covalently bound inhibitor triggers EZH2 degradation through CHIP-mediated ubiquitination

Enhancer of zeste homolog 2 (EZH2) has been characterized as a critical oncogene and a promising drug target in human malignant tumors. The current EZH2 inhibitors strongly suppress the enhanced enzymatic function of mutant EZH2 in some lymphomas. However, the recent identification of a PRC2- and methyltransferase-independent role of EZH2 indicates that a complete suppression of all oncogenic functions of EZH2 is needed. Here, we report a unique EZH2-targeting strategy by identifying a gambogenic acid (GNA) derivative as a novel agent that specifically and covalently bound to Cys668 within the EZH2-SET domain, triggering EZH2 degradation through COOH terminus of Hsp70-interacting protein (CHIP)-mediated ubiquitination. This class of inhibitors significantly suppressed H3K27Me3 and effectively reactivated polycomb repressor complex 2 (PRC2)-silenced tumor suppressor genes. Moreover, the novel inhibitors significantly suppressed tumor growth in an EZH2-dependent manner, and tumors bearing a non-GNA-interacting C668S-EZH2 mutation exhibited resistance to the inhibitors. Together, our results identify the inhibition of the signaling pathway that governs GNA-mediated destruction of EZH2 as a promising anti-cancer strategy.

Nuclear survivin promoted by acetylation is associated with the aggressive phenotype of oral squamous cell carcinoma

Defects in apoptotic pathway contribute to development and progression of oral cancer. Survivin, a member of the inhibitors of apoptosis protein (IAP) family, is increased in many types of cancers. However, it is unclear whether increased survivin is associated with oral squamous cell carcinomas (OSCC), and what mechanisms may involve in. In this study, we examined survivin expression in OSCC compared with normal oral tissues via immunohistochemical staining. The results showed that, not only total survivin is increased in OSCCs, but also the subcellular location of survivin is changed in OSCCs compared with normal oral tissues. In most of normal oral tissues, survivin staining was either negative, or cytoplasmic positive/nuclear negative; whereas in most of OSCC tissues, survivin staining was nuclear positive. Statistic analysis indicates that nuclear survivin, rather than total or cytoplasmic one, correlates with tumor TNM stage and differentiation grade. Consistently, in vitro analysis showed that survivin is in cytoplasm in normal human oral kinotinocyte (HOK) cells; whereas it is in nucleus in OSCC HN6 cells. Importantly, treatment of HOK cells with HDAC inhibitor Trichostatin A (TSA) induces survivin acetylation and promotes its nuclear localization. Moreover, nuclear survivin in OSCC cells was acetylated at K129 in its C-terminal, suggesting that the acetylation is important for nuclear location of survivin. Our study demonstrates that it is nuclear survivin, rather than total or cytoplasmic one, associates with TNM stage and tumor grade of OSCC. Thus, we propose nuclear survivin as a prognostic marker for the progression of OSCC.

Repression of GPRC5A is associated with activated STAT3, which contributes to tumor progression of head and neck squamous cell carcinoma

Background

G protein–coupled receptor family C group 5 member A (GPRC5A), a retinoic acid-inducible gene, is a lung tumor suppressor. Previously, we showed that repression of GPRC5A expression was associated with pathologic differentiation grade of oral squamous cell carcinomas (OSCC) and overexpression of GPRC5A gene inhibited the malignant phenotype in OSCC cells, suggesting that GPRC5A also functions as a tumor suppressor in oral cancer. However, the molecular mechanisms underlying GPRC5A deficiency in head and neck squamous cell carcinoma (HNSCC) are still unclear.

Methods

In this study, we used Western blot analysis and immunohistochemical (IHC) staining to investigate the expression of GPRC5A in both HNSCC cell lines and clinical samples. GPRC5A stable transfectants and their parental HNSCC cells were characterized for their biological activities in anchorage-independent growth.

Results

IHC analysis showed that, GPRC5A expression was high in normal tissue, but gradually decreased in oral leukoplakia, a precancerous stage, and greatly suppressed in primary cancer. Repression of GPRC5A was correlated with activated STAT3, which associates with aggressive clinicopathological features in HNSCC patients. Moreover, overexpression of GPRC5A suppressed IL-6-induced-STAT3 activation and inhibited anchorage-independent growth in HNSCC cells.

Conclusions

Repressed GPRC5A associates with increased tumor grade and activated STAT3, which may be used as a prognostic marker for tumor progression of HNSCC.

[Cost-effectiveness analysis on colorectal cancer screening program]

Objective: To evaluate the cost-effectiveness of colorectal cancer screening program in different age groups from the view of health economics. Methods: The screening compliance rates, detection rates in different age groups were calculated by using the data from colorectal cancer screening program in Jiashan county, Zhejiang province. The differences in indicator among age groups were analyzed with χ(2) test or trend χ(2) test. The ratios of cost to the number of case were calculated according to cost statistics. Results: The detection rates of immunochemical fecal occult blood test (iFOBT) positivity, advanced adenoma and colorectal cancer and early stage cancer increased with age, while the early diagnosis rates were negatively associated with age. After exclusion the younger counterpart, the cost-effectiveness of individuals aged >50 years could be reduced by 15%-30%. Conclusion: From health economic perspective, it is beneficial to start colorectal cancer screening at age of 50 years to improve the efficiency of the screening.

High Vimentin Expression Associated with Lymph Node Metastasis and Predicated a Poor Prognosis in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a common public health problem worldwide with poor prognosis, which is largely due to lymph node metastasis and recurrence. Identification of specific molecular markers of OSCC with lymph node metastasis would be very important for early and specific diagnosis. In this study, we screened for the potential prognosis markers via unbiased transcriptomic microarray analysis in paired two OSCC cell lines, a lymph node metastatic HN12 cell line and a low metastatic parental HN4 cell line. The results showed that vimentin, with 87-fold increase of expression, was on the top of all upregulated genes in metastatic HN12 cells compared to non-metastatic HN4 cells. Treatment of non-metastatic HN4 cells with TGF-β1 induced epithelial to mesenchymal transition (EMT), with increased vimentin expression as well as enhanced migration activity. Consistently, knockdown of vimentin via siRNA resulted in suppressed invasion and migration activities of HN12 cells, suggesting an essential role of vimentin in EMT-related functions of OSCC cells. Finally, immunohistochemical (IHC) staining analysis showed that high vimentin expression was strongly associated with high lymph node metastases (p < 0.05), and poor overall survival (p < 0.05) in OSCC patients. Thus, high vimentin expression is strongly associated with increased metastatic potential, and may serve as a prediction marker for poor prognosis in OSCC patients.

Ubiquitin-specific protease 14 regulates cell proliferation and apoptosis in oral squamous cell carcinoma

Ubiquitin-specific protease 14, a deubiquitinating enzyme, has been implicated in the tumorigenesis and progression of several cancers, but its role in oral squamous cell carcinoma remains to be elucidated. The aim of this study was to explore the expression pattern and roles of Ubiquitin-specific protease 14 in the occurrence and development of oral squamous cell carcinoma. Interestingly, Ubiquitin-specific protease 14 was overexpressed in oral cancer tissues and cell lines at both mRNA and protein levels. b-AP15, a specific inhibitor of Ubiquitin-specific protease 14, significantly inhibited the growth of cancer cells and increased cell apoptosis in a dose-dependent manner. Moreover, knockdown of Ubiquitin-specific protease 14 by shRNA significantly inhibited the proliferation and migration of cancer cells in vitro. Finally, using a xenograft mouse model of oral squamous cell carcinoma, knockdown of Ubiquitin-specific protease 14 markedly inhibited tumor growth and triggered the cancer cell apoptosis in vivo, supporting previous results. In conclusion, for the first time we have demonstrated the expression pattern of Ubiquitin-specific protease 14 in oral squamous cell carcinoma and verified a relationship with tumor growth and metastasis. These results may highlight new therapeutic strategies for tumor treatment, application of Ubiquitin-specific protease 14 selective inhibitor, such as b-AP15, or knockdown by shRNA. Collectively, Ubiquitin-specific protease 14 could be a potential therapeutic target for oral squamous cell carcinoma patients.

Autocrine epiregulin activates EGFR pathway for lung metastasis via EMT in salivary adenoid cystic carcinoma

Salivary adenoid cystic carcinoma (SACC) is characterized by invasive local growth and a high incidence of lung metastasis. Patients with lung metastasis have a poor prognosis. Treatment of metastatic SACC has been unsuccessful, largely due to a lack of specific targets for the metastatic cells. In this study, we showed that epidermal growth factor receptors (EGFR) were constitutively activated in metastatic lung subtypes of SACC cells, and that this activation was induced by autocrine expression of epiregulin (EREG), a ligand of EGFR. Autocrine EREG expression was increased in metastatic SACC-LM cells compared to that in non-metastatic parental SACC cells. Importantly, EREG-neutralizing antibody, but not normal IgG, blocked the autocrine EREG-induced EGFR phosphorylation and the migration of SACC cells, suggesting that EREG-induced EGFR activation is essential for induction of cell migration and invasion by SACC cells. Moreover, EREG-activated EGFR stabilized Snail and Slug, which promoted EMT and metastatic features in SACC cells. Of note, targeting EGFR with inhibitors significantly suppressed both the motility of SACC cells in vitro and lung metastasis in vivo. Finally, elevated EREG expression showed a strong correlation with poor prognosis in head and neck cancer. Thus, targeting the EREG-EGFR-Snail/Slug axis represents a novel strategy for the treatment of metastatic SACC even no genetic EGFR mutation.

Association of MDM2 promoter T309G polymorphism with oral cancer risk: A meta-analysis of 3,536 subjects

The mouse double minute 2 (MDM2) gene is an important regulator of the p53 suppressor gene. To date, evidence concerning the association of the MDM2 single nucleotide polymorphism (SNP) 309T>G (rs2279744) with the risk of developing oral squamous cell carcinoma (OSCC) remains controversial. Therefore, a meta-analysis of all the eligible studies was performed, in order to derive a more precise estimation of this association. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the degree of association in 5 previous studies, including a total of 1,369 OSCC cases and 2,167 controls. The overall analysis revealed a significant association between MDM2 SNP309 and OSCC risk in the heterozygote (TG vs. TT: OR=0.81; 95% CI: 0.68-0.96; P=0.02) and dominant models (TG+GG vs. TT: OR=0.82; 95% CI: 0.69-0.97; P=0.02). The subgroup analysis based on the source of the controls revealed a significant association between population-based controls and the heterozygote model (TG vs. TT: OR=0.75; 95% CI: 0.62-0.91; P=0.004), dominant model (TG+GG vs. TT: OR=0.76; 95% CI: 0.63-0.91; P=0.003) and allele comparison (G vs. T: OR=0.89; 95% CI: 0.79-0.99; P=0.04). Importantly, no evidence of publication bias or obvious heterogeneity were observed in the meta-analysis. The results of the present study demonstrated a decreased risk of developing OSCC for the MDM2 SNP309 group, suggesting MDM2 SNP309 may be a protection-associated genetic variation for OSCC. Additional well-designed studies, with larger sample sizes, are required to further elucidate this association.

G9a is essential for EMT-mediated metastasis and maintenance of cancer stem cell-like characters in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a particularly aggressive cancer with poor prognosis, largely due to lymph node metastasis and local recurrence. Emerging evidence suggests that epithelial-to-mesenchymal transition (EMT) is important for cancer metastasis, and correlated with increased cancer stem cells (CSCs) characteristics. However, the mechanisms underlying metastasis to lymph nodes in HNSCC is poorly defined. In this study, we show that E-cadherin repression correlates with cancer metastasis and poor prognosis in HNSCC. We found that G9a, a histone methyltransferase, interacts with Snail and mediates Snail-induced transcriptional repression of E-cadherin and EMT, through methylation of histone H3 lysine-9 (H3K9). Moreover, G9a is required for both lymph node-related metastasis and TGF-β-induced EMT in HNSCC cells since knockdown of G9a reversed EMT, inhibited cell migration and tumorsphere formation, and suppressed the expression of CSC markers. Our study demonstrates that the G9a protein is essential for the induction of EMT and CSC-like properties in HNSCC. Thus, targeting the G9a-Snail axis may represent a novel strategy for treatment of metastatic HNSCC.

Phase II trial of second-line everolimus in patients with metastatic renal cell carcinoma (RECORD-4)

BACKGROUND

RECORD-1 demonstrated clinical benefit of everolimus in patients with metastatic renal cell carcinoma (mRCC) previously treated with sunitinib, sorafenib, or both; prior treatment with cytokines, bevacizumab, and chemotherapy was also permitted. RECORD-4 prospectively assessed everolimus in a purely second-line setting.

METHODS

Patients with clear-cell mRCC were enrolled into one of three cohorts based on first-line therapy with sunitinib, other anti-VEGF agents, or cytokines. Patients were treated with everolimus 10 mg/day until progression (RECIST, v1.0) or intolerance. The primary end point was progression-free survival (PFS) per investigator review. Data cutoff was 1 September 2014, for the primary analysis and 26 June 2015, for the final overall survival (OS) analysis.

RESULTS

Enrolled patients (N = 134) previously received sunitinib (n = 58), other anti-VEGF therapy (n = 62; sorafenib, 23; bevacizumab, 16; pazopanib, 13; tivozanib, 5; and axitinib, 3), or cytokines (n = 14). Overall median age was 59 years, and most patients were men (68%) and of favorable/intermediate MSKCC risk (52/37%). Overall median PFS was 7.8 months [95% confidence interval (CI) 5.7-11.0]; in the cohorts, it was 5.7 months (95% CI 3.7-11.3) with previous sunitinib, 7.8 months (95% CI 5.7-11.0) with other previous anti-VEGF therapy, and 12.9 months [95% CI 2.6-not estimable (NE)] with previous cytokines. Overall, 67% of patients achieved stable disease as their best objective response. At final OS analysis, total median OS was 23.8 months (95% CI 17.0-NE) and, in the cohorts, it was 23.8 months (95% CI 13.7-NE) with previous sunitinib, 17.2 months (95% CI 11.9-NE) with other previous anti-VEGF therapy, and NE (95% CI 15.9-NE) with previous cytokine-based therapy. Overall, 56% of patients experienced grade 3 or 4 adverse events (regardless of relationship to study drug).

CONCLUSIONS

These results confirm the PFS benefit of second-line everolimus after first-line sunitinib or other anti-VEGF therapies. The safety profile of everolimus was consistent with previous experience.

CLINICAL TRIAL NAME AND IDENTIFIER

Everolimus as Second-line Therapy in Metastatic Renal Cell Carcinoma (RECORD-4), ClinicalTrials.gov identifier, NCT01491672.

Association of the XPA A23G polymorphism with the risk of head and neck carcinomas: Evidence from 5,491 subjects

The XPA gene participates in modulating DNA damage recognition during the DNA nucleotide excision repair process. Current data regarding the association of the XPA A23G polymorphism with the risk of head and neck squamous cell carcinoma (HNSCC) remain controversial, and meta-analyses focusing on the HNSCC risk and this polymorphism are limited. Therefore, the aim of the present study was to derive a more precise estimation of this association by a meta-analysis of all the eligible studies. Odds ratios (ORs) with 95% confidence intervals (CI) were assessed for the strength of the associations in eight studies, including 5,491 subjects (2,409 HNSCC cases and 3,082 controls). The overall analysis revealed that the XPA A23G polymorphism was not significantly associated with the overall HNSCC risk. Consistently, there was no evidence for the association between the XPA A23G polymorphism and HNSCC risk in subgroup analyses based on ethnicity and the source of controls. However, the significant associations in oral carcinoma with the increased risk among the XPA heterozygote (AG vs. AA: OR, 1.58; 95% CI, 1.06-2.37; P_{heterogeneity}=0.23, I²=30%) and dominant (AG +GG vs. AA: OR, 1.53; 95% CI, 1.04-2.23; P_{heterogeneity}=0.21, I²=36%) models were observed in the subgroup analysis by tumor site. In conclusion, the meta-analysis suggested that the XPA A23G polymorphism was not associated with overall HNSCC susceptibility, but it was associated with oral carcinoma susceptibility and it may be a risk factor for oral carcinoma. Further well-designed and large studies are required to confirm these associations.