Decreased adiponectin level is associated with aggressive phenotype of tongue squamous cell carcinoma

The adipokines in oral cancer pathogenesis and its potential as a new therapeutic approach

The involvement of adipose tissue in the development of cancer is currently the subject of an increasing number of research due to the growing relevance of lipid metabolism in tumor growth. Obesity influences the tumor immune microenvironment (TME) in oral cancer. Visceral white adipose tissue (WAT) consists of adipocytes, connective tissue, immune cells, and stromovascular cells. The metabolic processes of immune cells within the adipose tissue of individuals with obesity predominantly depend on oxidative phosphorylation (intrinsically) and are characterized by elevated levels of M2 macrophages, Treg cells, Th2 cells, and eosinophils from an extrinsic perspective. The adipokines secreted by adipocytes facilitate communication with adjacent tissues to regulate glucose and lipid metabolism. Obesity influences cancer progression through the dysregulation of adipocytokines, characterized by an augmented synthesis of the oncogenic adipokine leptin, coupled with a reduced secretion of adiponectin. Under standard physiological settings, these adipokines fulfill essential roles in sustaining homeostasis. This review analyzed the influence of adipocytes on oral cancer by detailing the mediators released by adipocytes. Comprehending the molecular foundations of the protumor roles of adipokines in oral cancers might provide novel treatment targets.

Causal association of serum biomarkers with oral cavity and oropharyngeal cancer: a mendelian randomization study

BACKGROUND

Observational epidemiological studies revealed that multiple serum biomarkers can be associated with the risk of oral and oropharyngeal cancer (OC/OPC). However, the causal relationship between them remains largely unknown. This study aimed to investigate the causal relationship between potential serum biomarkers and (OC/OPC).

METHODS

A two-sample Mendelian randomization (MR) approach was performed to assess the causal association of 10 serum biomarkers with the risk of OC / OPC. Summary data on OC/OPC were obtained from a GWAS meta-analysis that included 2497 cases and 2928 controls. The TwoSampleMR package in R was used to perform MR analyzes. Inverse-variance weighted (IVW), Weighted median and MR-Egger methods were used to assess causal effects.

RESULTS

Suggestive associations with increased risk of C-reactive protein (CRP) (OR 1.52, 95% CI 1.14 to 2.02), using the IVW method. MR-Egger regression suggested that directional pleiotropy was unlikely to bias the result (P = 0.19). The findings were robust to sensitivity analyzes. The risk of OC/OPC was not associated with serum 25-hydroxyvitamin D, HDL cholesterol, LDL cholesterol, total cholesterol, triglycerides, adiponectin, leptin, HbA1C and Insulin-like growth factor 1 (IGF 1).

CONCLUSIONS

This study supports that CRP was causally associated with an increased risk of oral and oropharyngeal cancer.

The locoregional adiponectin and its synergistic antitumor effect with HIF-1α blockade in TSCC

Adiponectin (APN) is a kind of endogenous anti-tumor adipocytokine, which exerts its function by binding to its receptors (AdipoR1 and AdipoR2). However, hyperadiponectinemia is found in some pathophysiological processes without significant protective effect, which indicates the existence of APN resistance. Here, we aimed to investigate the locoregional expression of APN in tongue squamous cell carcinoma (TSCC) tissues, and to explore the potential regulatory mechanism of APN resistance under hypoxia. Consequently, we found that the protein expression of APN and AdipoR1, but not AdipoR2, was upregulated in the early stage of TSCC and after hypoxic treatment ex vivo and in vitro. Knockdown of HIF-1α decreased the level of APN and AdipoR1, and simultaneously, HIF-1α was identified as transcriptor of the APN. Intriguingly, a regenerative feedback of HIF-1α was unexpectedly detected after application of recombinant globular APN (gAPN), which most likely contributed to the APN resistance. Furthermore, HIF-1α blockade combined with gAPN has a prominent synergistic antitumor effect, which suggested an effective amelioration in APN resistance. In all, our study revealed the possible mechanism of APN resistance under hypoxia and provides a promising strategy of bi-target treatment with APN and HIF-1α for TSCC therapy.

Adiponectin Suppresses Metastasis of Nasopharyngeal Carcinoma through Blocking the Activation of NF-κB and STAT3 Signaling

Adiponectin is an adipocytokine with anti-inflammatory and anticancer properties. Our previous study has shown that blood adiponectin levels were inversely correlated to the risk of nasopharyngeal carcinoma (NPC), and that adiponectin could directly suppress the proliferation of NPC cells. However, the effect of adiponectin on NPC metastasis remains unknown. Here, we revealed in clinical studies that serum adiponectin level was inversely correlated with tumor stage, recurrence, and metastasis in NPC patients, and that low serum adiponectin level also correlates with poor metastasis-free survival. Coculture with recombinant adiponectin suppressed the migration and invasion of NPC cells as well as epithelial-mesenchymal transition (EMT). In addition, recombinant adiponectin dampened the activation of NF-κB and STAT3 signaling pathways induced by adipocyte-derived proinflammatory factors such as leptin, IL-6, and TNF-α. Pharmacological activation of adiponectin receptor through its specific agonist, AdipoRon, largely stalled the metastasis of NPC cells. Taken together, these findings demonstrated that adiponectin could not only regulate metabolism and inhibit cancer growth, but also suppress the metastasis of NPC. Pharmacological activation of adiponectin receptor may be a promising therapeutic strategy to stall NPC metastasis and extend patients' survival.

Perspectives of lipid metabolism reprogramming in head and neck squamous cell carcinoma: An overview

Recent studies showed that lipid metabolism reprogramming contributes to tumorigenicity and malignancy by interfering energy production, membrane formation, and signal transduction in cancers. HNSCCs are highly reliant on aerobic glycolysis and glutamine metabolism. However, the mechanisms underlying lipid metabolism reprogramming in HNSCCs remains obscure. The present review summarizes and discusses the "vital" cellular signaling roles of the lipid metabolism reprogramming in HNSCCs. We also address the differences between HNSCCs regions caused by anatomical heterogeneity. We enumerate these recent findings into our current understanding of lipid metabolism reprogramming in HNSCCs and introduce the new and exciting therapeutic implications of targeting the lipid metabolism.

CTRP3 promotes TNF-α-induced apoptosis and barrier dysfunction in salivary epithelial cells

BACKGROUND

C1q/tumour necrosis factor-related protein 3 (CTRP3) plays important roles in metabolism and inflammatory responses in various cells and tissues. However, the expression and function of CTRP3 in salivary glands have not been explored.

METHODS

The expression and distribution of CTRP3 were detected by western blot, polymerase chain reaction, immunohistochemical and immunofluorescence staining. The effects of CTRP3 on tumour necrosis factor (TNF)-α-induced apoptosis and barrier dysfunction were detected by flow cytometry, western blot, co-immunoprecipitation, and measurement of transepithelial resistance and paracellular tracer flux.

RESULTS

CTRP3 was distributed in both acinar and ductal cells of human submandibular gland (SMG) and was primarily located in the ducts of rat and mouse SMGs. TNF-α increased the apoptotic rate, elevated expression of cleaved caspase 3 and cytochrome C, and reduced B cell lymphoma-2 (Bcl-2) levels in cultured human SMG tissue and SMG-C6 cells, and CTRP3 further enhanced TNF-α-induced apoptosis response. Additionally, CTRP3 aggravated TNF-α-increased paracellular permeability. Mechanistically, CTRP3 promoted TNF-α-enhanced TNF type I receptor (TNFR1) expression, inhibited the expression of cellular Fas-associated death domain (FADD)-like interleukin-1β converting enzyme inhibitory protein (c-FLIP), and increased the recruitment of FADD with receptor-interacting protein kinase 1 and caspase 8. Moreover, CTRP3 was significantly increased in the labial gland of Sjögren's syndrome patients and in the serum and SMG of nonobese diabetic mice.

CONCLUSIONS

These findings suggest that the salivary glands are a novel source of CTRP3 synthesis and secretion. CTRP3 might promote TNF-α-induced cell apoptosis through the TNFR1-mediated complex II pathway.

Circular RNA expression profiling identifies specific circular RNAs in tongue squamous cell carcinoma

Tongue squamous cell carcinoma (TSCC) is the most frequent type of oral cancer associated with high malignancy. Circular RNAs (circRNAs) are a form of non-coding RNA with stable and conserved expression in mammalian cells. The aim of the present study was to investigate circRNAs expression profiles in TSCC, and examine the roles and potential mechanisms of circRNA-081069 (circ_081069). A high-throughput circRNA microarray analysis of tumor samples and adjacent normal tissues from four patients with TSCC was performed. Bioinformatic analysis was conducted to screen the differentially expressed circRNAs. Reverse transcription-quantitative PCR was performed to confirm the microarray results. A migration assay and proliferation assay were performed to detect the migratory and proliferative ability of TSCC cells. A luciferase assay was conducted to investigate the interaction between circ_081069 and microRNA (miRNA/miR)-665. In total, 335 circRNAs were found to be differentially expressed in tumor tissues. Among them, 59 were upregulated and 276 were downregulated (P<0.05; fold change ≥2 or ≤0.5). A total of seven circRNAs, including two upregulated and five downregulated circRNAs, were further confirmed using quantitative PCR analysis in the ten paired TSCC tissues and adjacent normal tissues. The present study showed that circRNA_081069 promoted the migratory and proliferative ability of TSCC cells in vitro. Furthermore, the potential circRNA-miRNA interactions were predicted, and the present results identified miR-665 as a miRNA target of circ_081069. The present results suggested that circRNAs may be involved in TSCC development, and understanding the interaction between circ_081069 and miR-665 may facilitate the development of novel diagnostic and therapeutic targets for TSCC.

Obesity: An emerging driver of head and neck cancer

Obesity has become pandemic and emerged as one of the most critical global health care problems worldwide since last century. Recent studies have demonstrated that there may be a causal link between obesity and higher risks and mortality of cancers, including prostate, breast, colon, and thyroid cancers, head and neck cancer (HNC). This review focuses on the relationship between obesity and HNC, and the molecular mechanism of abnormal lipid metabolism in HNC. Elucidating the mechanism may open up new possibilities for strategies to reduce risk and mortality of HNC in an increasingly obese population.

The oncogenic potential of PRR11 gene in Tongue Squamous Cell Carcinoma cells

Background: We previously demonstrated that Proline rich 11 (PRR11) gene is associated with the development and progression of tongue squamous cell carcinoma (TSCC), but the underlying mechanism is unknown. This study aimed to investigate the molecular mechanism underlying oncogenic potential of PRR11 in TSCC cells. Methods: Overexpression and knockdown of PRR11 were performed by plasmid transfection into SCC15 and HSC3 human TSCC cells. Expressions of mRNA and protein were assessed by qRT-PCR and Western blot, respectively. Cell proliferation and invasion were determined by CCK-8 and Transwell assay, respectively. In vivo tumor growth and cell cycle were determined by a nude mice model of subcutaneous tumorigenesis and flow cytometry, respectively. Results: Overexpression of PRR11 significantly enhanced TSCC cells proliferation and the invasive ability of TSCC cells, whereas PRR11 knockdown in TSCC cells exhibited a reverse trend. In addition, the in vivo subcutaneous tumorigenicity assay showed that PRR11 knockdown significantly reduced tumor size and the Ki67 (a proliferation marker)expression in the tumor tissue. Flow cytometry analysis revealed that PRR11 overexpression significantly decreased the proportion of cells in S phase, whereas PRR11 knockdown in TSCC cells exhibited a reverse trend. Furthermore, PRR11 overexpression simultaneously down-regulated two cyclin-dependent kinase inhibitors (CKIs), p21 and p27 and up-regulated CDK2 and Cyclin A2 in TSCC cells. PRR11 knockdown again exhibited reverse trends of expressions of the above proteins.Conclusion: These results suggested that PRR11 promoted cell proliferation by regulating the expressions of p21, p27, CDK2 and Cyclin A to facilitate S/G phase transition in TSCC cells.

A review of the most promising biomarkers for early diagnosis and prognosis prediction of tongue squamous cell carcinoma

BACKGROUND

There is a great interest in developing biomarkers to enhance early detection and clinical management of tongue squamous cell carcinoma (TSCC). However, the developmental path towards a clinically valid biomarker remains extremely challenging. Ideally, the initial key step in moving a newly discovered biomarker towards clinical implementation is independent replication. Therefore, the focus of this review is on biomarkers that consistently showed clinical relevance in two or more publications.

METHODS

We searched PubMed database for relevant papers across different TSCC sample sources, i.e., body fluids (saliva, serum/plasma) and tissues. No restriction regarding the date of publication was applied except for immunohistochemistry (IHC); only studies published between 2010 and June 2017 were included.

RESULTS

The search strategy identified 1429 abstracts, of which 96 papers, examining 150 biomarkers, were eventually included. Of these papers, 66% were exploratory studies evaluating single or a panel of biomarkers in one publication. Ultimately, based on studies that had undergone validation for their clinical relevance in at least two independent studies, we identified 10 promising candidates, consisting of different types of molecules (IL-6, IL-8, and Prolactin in liquid samples; HIF-1α, SOX2, E-cadherin, vimentin, MALAT1, TP53, and NOTCH1 in tissue biopsies) CONCLUSIONS: Although more exploratory research is needed with newer methods to identify biomarkers for TSCC, rigorous validation of biomarkers that have already shown unbiased assessment in at least two publications should be considered a high priority. Further research on these promising biomarkers or their combination in multi-institutional studies, could provide new possibilities to develop a specific panel for early diagnosis, prognosis, and individualized treatments.

The Role of Adipokines in the Establishment and Progression of Head and Neck Neoplasms

Adipokines constitute a family of protein factors secreted by white adipose tissue (WAT), that regulate the functions of WAT and other sites. Leptin, adiponectin and resistin, are the main adipokines present in serum and saliva, targeting several tissues and organs, including vessels, muscles, liver and pancreas. Besides body mass regulation, adipokines affect glucose homeostasis, inflammation, angiogenesis, cell proliferation and apoptosis, and other crucial cell procedures. Their involvement in tumor formation and growth is well established and deregulation of adipokine and adipokine receptors' expression is observed in several malignancies including those located in the head and neck region. Intracellular effects of adipokines are mediated by a plethora of receptors that activate several signaling cascades including Janus kinase/ Signal transducer and activator of transcription (JAK/ STAT pathway), Phospatidylinositol kinase (PI3/ Akt/ mTOR) and Peroxisome proliferator-activated receptor (PPAR). The present review summarizes the current knowledge on the role of adipokines family members in carcinogenesis of the head and neck region. The diagnostic and prognostic significance of adipokines and their potential role as serum and saliva biomarkers are also discussed.

Serum levels of selected adipocytokines in benign and malignant parotid gland tumor patients

OBJECTIVES

The aim of this study was to evaluate serum levels of adiponectin, leptin, visfatin and IL-6 in patients with pleomorphic adenoma, Warthin's tumor and acinic cell carcinoma of the parotid gland.

MATERIALS AND METHODS

Venous blood samples were collected from 30 patients with pleomorphic adenoma, 21 patients with Warthin's tumor and 8 patients with acinic cell carcinoma. Serum adiponectin, leptin, visfatin, IL-6 and CRP concentrations were determined.

RESULTS

Our results revealed significantly lower adiponectin serum levels in patients with malignant tumors compared to benign tumor individuals. Moreover, in benign cases the level was significantly higher compared to controls. Furthermore, serum leptin concentrations of benign tumor patients were higher compared to controls. Those differences, however, were observed only in males. The serum visfatin level was elevated in all tumor subjects compared to healthy individuals, whereas the serum IL-6 concentration was similar.

CONCLUSIONS

We anticipate that adiponectin may play a potential protective role in salivary gland tumors. Also leptin and visfatin seem to play an important role in salivary gland tumor pathology, although in males and females leptin may act or be regulated in a different manner. The influence of visfatin on salivary gland tumors is probably independent of IL-6 production.

Circulating adiponectin levels in various malignancies: an updated meta-analysis of 107 studies

Early detection of cancers is challenging for lack of specific biomarkers. Adiponectin is an adipokine predominantly derived from adipocytes and hypoadiponectinemia has been reported to associate with risk of many types of cancers. However, available evidence is controversial. Some studies show that increased adiponectin levels correlate with cancer risk. Therefore, we performed a meta-analysis of the association between circulating adiponectin levels and cancer development. A systematic search of PubMed, EMBASE, Wiley Online Library and Cochrane Library was conducted for eligible studies involving circulating adiponectin and malignancies from inception to August 8, 2015. Standard mean differences (SMDs) with 95% confidence intervals (95% CIs) were calculated by use of a random-effect model. Funnel plot and Egger's linear regression test were conducted to examine the risk of publication bias. 107 studies were included with 19,319 cases and 25,675 controls. The pooled analysis indicated that circulating adiponectin levels were lower in patients with various cancers than in controls, with a pooled SMD of −0.334 μg/ml (95% CI, −0.465 to −0.203, P = 0.000). No evidence of publication bias was observed. Circulating high molecular weight adiponectin levels were also lower in cancer patients than in controls, with a pooled SMD of −0.502 μg/ml (95% CI, −0.957 to −0.047, P = 0.000). This meta-analysis provides further evidence that decreased adiponectin levels is associated with risk of various cancers. Hypoadiponectinemia may represent a useful biomarker for early detection of cancers.

Isobavachalcone inhibits the proliferation and invasion of tongue squamous cell carcinoma cells

Isobavachalcone (2′,4′,4-trihydroxy-3′-[3′-methylbut-3′-ethyl] chalcone or IBC) exhibits anticancer activities in a number of types of cancer cell. However, its role in tongue squamous cell carcinoma (TSCC) cells remains unclear. The aim of the present study was to investigate the biological effect of IBC in TSCC Tca8113 cells. The function of IBC on Tca8113 cell apoptosis and apoptosis-associated signaling pathways was determined using an MTT assay, morphological staining, annexin V-propidium iodide (PI) staining and Western blot analysis. The effects of IBC on Tca8113 cell migration, invasion and relative protein expression were confirmed using wound healing analysis, Transwell invasion analysis and Western blot analysis, respectively. The results of the MTT assay and annexin V-PI staining indicated that IBC is able to significantly inhibit proliferation and induce apoptosis of Tca8113 cells in vitro. IBC treatment resulted in typical apoptotic morphology of nuclear fragmentation and apoptotic bodies in Tca8113 cells. Western blot analysis further demonstrated that IBC caused downregulation of the expression of B-cell lymphoma 2 (Bcl-2) protein, upregulation of the expression of Bcl-2-associated X protein (Bax), activation of caspases, and dephosphorylation of protein kinase B (Akt) and extracellular-signal-regulated kinase (ERK) proteins in a concentration- and time-dependent manner. The results of the present study suggest that IBC induces apoptosis in Tca8113 cells and that the induction may be associated with the activation of Bcl-2, Bax and caspase-3, and the inactivation of Akt and ERK. Furthermore, IBC inhibited migration and invasion of Tca8113 cells in vitro by downregulating matrix metalloproteinase (MMP)-2 and MMP-9 protein expression. The results of the present study indicate that IBC may be a potential anticancer drug for the treatment of TSCC.

Obesity and cancer: the role of adipose tissue and adipo-cytokines-induced chronic inflammation

Adipose tissue in addition to its ability to keep lipids is now recognized as a real organ with both metabolic and endocrine functions. Recent studies demonstrated that in obese animals is established a status of adipocyte hypoxia and in this hypoxic state interaction between adipocytes and stromal vascular cells contribute to tumor development and progression. In several tumors such as breast, colon, liver and prostate, obesity represents a poor predictor of clinical outcomes. Dysfunctional adipose tissue in obesity releases a disturbed profile of adipokines with elevated levels of pro-inflammatory factors and a consequent alteration of key signaling mediators which may be an active local player in establishing the peritumoral environment promoting tumor growth and progression. Therefore, adipose tissue hypoxia might contribute to cancer risk in the obese population. To date the precise mechanisms behind this obesity-cancer link is not yet fully understood. In the light of information provided in this review that aims to identify the key mechanisms underlying the link between obesity and cancer we support that inflammatory state specific of obesity may be important in obesity-cancer link.

The role of serum biomarkers in the diagnosis and prognosis of oral cancer: A systematic review

Introduction

Oral cancer is one of the causes of major morbidity and mortality in the world although incidence varies in the different geographical locations and races. Advances in molecular biology and cancer research have allowed elucidating serum biomarkers to improve diagnostic methods. The aim of this article systematic review is to highlight the utility and clinical value of serum biomarkers in the diagnosis and prognosis of oral cancer.

Material and Methods

A systematic literature review using PubMed (MEDLINE databases) revealed a total of 140 articles related to this topic. Of those articles, 29 were included in the final review. We included articles published in English in the last five years, developed in human as cases and controls studies, retrospective or prospective studies and specific studies that analyzed a certain biomarker in serum.

Results

All of the studies include in this systematic review found significant differences in patients. Of those articles included, 2 used biomarkers to determinate cancerous phenotype, 11 mentioned their results were associated with worse prognosis and overall survival, 4 correlated biomarker concentration to clinical stages, 4 concluded it could be a helpful in diagnosis and 8 studies did not find a clear utility of the analysed biomarker. Due to differences in the presentation of data, meta-analysis was not possible.

Conclusions

Biomarker use for diagnosis and prognosis is supported by clinical and scientific evidence is relevant. Nevertheless, after selecting a certain biomarker, monitoring protocols should be established in oral and maxillofacial surgeons teams so as we have a correct understanding of biological values.

Key words:Serum biomarkers, oral cancer, diagnosis, prognosis.

Decreased submandibular adiponectin is involved in the progression of autoimmune sialoadenitis in non-obese diabetic mice

OBJECTIVE

To investigate a possible role of adiponectin in the pathogenesis of autoimmune sialoadenitis in non-obese diabetic (NOD) mouse model of Sjögren's syndrome.

MATERIALS AND METHODS

Expression of adiponectin and its receptors (AdipoR1/2) was detected by PCR, immunoblotting, or immunofluorescence. The level of adiponectin was quantified by ELISA. Adiponectin-related signaling molecules and pro-inflammatory cytokines were examined by PCR or immunoblotting. Apoptosis was evaluated by TUNEL staining, flow cytometry, and caspase 3 activation.

RESULTS

Adiponectin and AdipoR1/2 mRNA and protein were expressed in submandibular glands. Adiponectin immunostaining was widely diffused in the cytoplasm of acinar and ductal cells. AdipoR1 was mainly distributed in acinar cytoplasm, while AdipoR2 was predominantly located at acinar cell membrane. Submandibular adiponectin levels were reduced during the progression of autoimmune sialoadenitis in 7-, 14-, and 21-week-old NOD mice, while AdipoR1/2 levels were unchanged. The levels of phosphorylated adenosine monophosphate-activated protein kinase, extracellular signal-regulated kinase 1/2, and p38 mitogen-activated protein kinase were decreased, while interferon (IFN)-γ and glandular apoptosis were temporally increased at all time points. Moreover, exogenous adiponectin supplement inhibited, whereas neutralizing endogenous adiponectin by its antibody promoted IFN-γ-induced apoptosis and caspase 3 activation in cultured submandibular acinar cells.

CONCLUSIONS

Adiponectin plays a protective role on submandibular cells. Decreased adiponectin might promote glandular destruction in autoimmune sialoadenitis.