Clinical and tumor significance of tropomyosin-1 expression levels in renal cell carcinoma

A novel induced pluripotent stem cell model of Schwann cell differentiation reveals NF2 - related gene regulatory networks of the extracellular matrix

Schwann cells are vital to development and maintenance of the peripheral nervous system and their dysfunction has been implicated in a range of neurological and neoplastic disorders, including NF2 -related schwannomatosis. We developed a novel human induced pluripotent stem cell (hiPSC) model to study Schwann cell differentiation in health and disease. We performed transcriptomic, immunofluorescence, and morphological analysis of hiPSC derived Schwann cell precursors (SPCs) and terminally differentiated Schwann cells (SCs) representing distinct stages of development. To validate our findings, we performed integrated, cross-species analyses across multiple external datasets at bulk and single cell resolution. Our hiPSC model of Schwann cell development shared overlapping gene expression signatures with human amniotic mesenchymal stem cell (hAMSCs) derived SCs and in vivo mouse models, but also revealed unique features that may reflect species-specific aspects of Schwann cell biology. Moreover, we identified gene co-expression modules that are dynamically regulated during hiPSC to SC differentiation associated with ear and neural development, cell fate determination, the NF2 gene, and extracellular matrix (ECM) organization. By cross-referencing results between multiple datasets, we identified new genes potentially associated with NF2 expression. Our hiPSC model further provides a tractable platform for studying Schwann cell development in the context of human disease.

The Actin Cytoskeleton as a Regulator of Proteoglycan 4

OBJECTIVE

The superficial zone (SZ) of articular cartilage is responsible for distributing shear forces for optimal cartilage loading and contributes to joint lubrication through the production of proteoglycan 4 (PRG4). PRG4 plays a critical role in joint homeostasis and is chondroprotective. Normal PRG4 production is affected by inflammation and irregular mechanical loading in post-traumatic osteoarthritis (PTOA). THe SZ chondrocyte (SZC) phenotype, including PRG4 expression, is regulated by the actin cytoskeleton in vitro. There remains a limited understanding of the regulation of PRG4 by the actin cytoskeleton in native articular chondrocytes. The filamentous (F)-actin cytoskeleton is a potential node in crosstalk between mechanical stimulation and cytokine activation and the regulation of PRG4 in SZCs, therefore developing insights in the regulation of PRG4 by actin may identify molecular targets for novel PTOA therapies.

MATERIALS AND METHODS

A comprehensive literature search on PRG4 and the regulation of the SZC phenotype by actin organization was performed.

RESULTS

PRG4 is strongly regulated by the actin cytoskeleton in isolated SZCs in vitro. Biochemical and mechanical stimuli have been characterized to regulate PRG4 and may converge upon actin cytoskeleton signaling.

CONCLUSION

Actin-based regulation of PRG4 in native SZCs is not fully understood and requires further elucidation. Understanding the regulation of PRG4 by actin in SZCs requires an in vivo context to further potential of leveraging actin arrangement to arthritic therapeutics.

LncRNA H19 promotes tumor angiogenesis in smokers by targeting anti-angiogenic miRNAs

A key concept in drug discovery is the identification of candidate therapeutic targets such as long noncoding RNAs (lncRNAs) because of their extensive involvement in neoplasms, and impressionability by smoking. Induced by exposure to cigarette smoke, lncRNA H19 targets and inactivates miR-29, miR-30a, miR-107, miR-140, miR-148b, miR-199a and miR-200, which control the rate of angiogenesis by inhibiting BiP, DLL4, FGF7, HIF1A, HIF1B, HIF2A, PDGFB, PDGFRA, VEGFA, VEGFB, VEGFC, VEGFR1, VEGFR2 and VEGFR3. Nevertheless, these miRNAs are often dysregulated in bladder cancer, breast cancer, colorectal cancer, glioma, gastric adenocarcinoma, hepatocellular carcinoma, meningioma, non-small-cell lung carcinoma, oral squamous cell carcinoma, ovarian cancer, prostate adenocarcinoma and renal cell carcinoma. As such, the present perspective article seeks to establish an evidence-based hypothetical model of how a smoking-related lncRNA known as H19 might aggravate angiogenesis by interfering with miRNAs that would otherwise regulate angiogenesis in a nonsmoking individual.

Proteomics study on the effect of silybin on cardiomyopathy in obese mice

Due to the increase in the number of obese individuals, the incidence of obesity-related complications such as cardiovascular disease and type 2 diabetes is higher. The aim of the present study was to explore the effects of silybin on protein expression in obese mice. Firstly, serum was collected, and it was used to detect serum lipids and other serological indicators. Secondly, total protein from epididymal adipose tissue was extracted for differential expression analysis by quantitative tandem mass tag (TMT) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS), followed by bioinformatics and protein-protein interaction (PPI) network analyses of these proteins. Lastly, real-time polymerase chain reaction (RT-PCR) and parallel reaction monitoring (PRM) were used to further validate the expression of identified differentially expressed proteins (DEPs) at the mRNA and protein level, respectively. The results revealed that silybin could improve abnormal lipid metabolism caused by the high fat diet in obese mice. A total of 341, 538 and 243 DEPs were found in the high fat/control (WF/WC), silybin/high fat (WS/WF) and WS/WC groups, respectively. These DEPs mainly participated in lipid metabolism and energy metabolism. Notably, tropomyosin 1 (TPM1), myosin light chain 2 (MYL2), myosin heavy chain 11 (MYH11) and other DEPs were involved in hypertrophic cardiomyopathy, dilated cardiomyopathy and other pathways. Silybin could protect cardiac function by inducing the protein expression of TPM1, MYL2 and MYH11 in the adipose tissue of obese mice.

LINC01116 facilitates colorectal cancer cell proliferation and angiogenesis through targeting EZH2-regulated TPM1

BACKGROUND

Colorectal cancer (CRC) is a common malignant tumor globally. Meanwhile, LINC01116 has been proposed as risk factor for various tumors, including CRC. But the regulation of LINC01116 in CRC required more validated data. This study aimed to elucidate the potential function of LINC01116 in regulating cell proliferation and angiogenesis of CRC.

METHODS

LINC01116 expression in 80 pairs of CRC tumor and adjacent non-tumor tissues was determined by qRT-PCR. After transfection of pcDNA3.1-LINC01116, sh-LINC01116, sh-TPM1, pcDNA3.1-EZH2 or sh-EZH2 in SW480 and HCT116 cells, the levels of LINC01116, TPM1 and EZH2 were measured by qRT-PCR or Western blot. The cell biological function of CRC cell lines was determined by CCK-8, colony formation assays, tube formation and scratch assays. RNA pull-down and RIP assays were applied to detect the binding of LINC01116 with EZH2 and H3K27me3. Binding of EZH2 to the TPM1 promoter was assessed by ChIP assay. Finally, xenograft models in nude mice were established to validate the results of in vitro experiments.

RESULTS

LINC01116 was overexpressed in CRC tissues and high expression of LINC01116 was negatively correlated with postoperative survival. In vitro study showed LINC01116 expression could significantly enhance CRC progression, including increasing cell proliferation, migration and angiogenesis. Besides, investigations into the mechanism disclosed that LINC01116 could regulate EZH2 to inactivate TPM1 promoter, thus promoting CRC cell proliferation and angiogenesis. Moreover, consistent results of in vivo experiments were conformed in vitro experiments.

CONCLUSION

LINC01116 promotes the proliferation and angiogenesis of CRC cells by recruiting EZH2 to potentiate methylation in the TPM1 promoter region to inhibit the transcription of TPM1.

Targeting the cytoskeleton against metastatic dissemination

Cancer is a pathology characterized by a loss or a perturbation of a number of typical features of normal cell behaviour. Indeed, the acquisition of an inappropriate migratory and invasive phenotype has been reported to be one of the hallmarks of cancer. The cytoskeleton is a complex dynamic network of highly ordered interlinking filaments playing a key role in the control of fundamental cellular processes, like cell shape maintenance, motility, division and intracellular transport. Moreover, deregulation of this complex machinery contributes to cancer progression and malignancy, enabling cells to acquire an invasive and metastatic phenotype. Metastasis accounts for 90% of death from patients affected by solid tumours, while an efficient prevention and suppression of metastatic disease still remains elusive. This results in the lack of effective therapeutic options currently available for patients with advanced disease. In this context, the cytoskeleton with its regulatory and structural proteins emerges as a novel and highly effective target to be exploited for a substantial therapeutic effort toward the development of specific anti-metastatic drugs. Here we provide an overview of the role of cytoskeleton components and interacting proteins in cancer metastasis with a special focus on small molecule compounds interfering with the actin cytoskeleton organization and function. The emerging involvement of microtubules and intermediate filaments in cancer metastasis is also reviewed.

Arecoline suppresses epithelial cell viability by upregulating tropomyosin-1 through the transforming growth factor-β/Smad pathway

CONTEXT

Oral submucous fibrosis (OSF) is a chronic and progressive disease. Arecoline, present in betel nuts, has been proposed as a vital aetiological factor. However, the underlying mechanism remains unclear.

OBJECTIVES

This research elucidates the expression of tropomyosin-1 (TPM1) and its regulation mechanism in HaCaT cells treated with arecoline.

MATERIALS AND METHODS

HaCaT cells were assigned into three groups: (1) Control; (2) Treated with arecoline (0.16 mM) for 48 h (3) Treated with arecoline (0.16 mM) and transfected with small interfering RNA (siRNA) for TPM1 (50 nM) for 48 h. CCK8, cell cycle, and apoptosis phenotypic analyses were performed. PCR and western blot analyses were performed to detect the expression level of TPM1 and examine the related signalling pathway.

RESULTS

The IC₅₀ of arecoline was approximately 50 μg/mL (0.21 mM). The arecoline dose (0.16 mM) and time (48 h) markedly increased TPM1 expression at the mRNA and protein levels in HaCaT cells. Arecoline suppressed the cell growth, caused cell cycle arrest at the G1 phase, and induced cell apoptosis in HaCaT cells. siRNA-mediated knockdown of TPM1 attenuated the effect of arecoline on cell proliferation, apoptosis, and cell cycle arrest at the G1 phase. Furthermore, blocking of the transforming growth factor (TGF)-β receptor using SB431542 significantly suppressed TPM1 expression in the cells treated with arecoline.

DISCUSSION AND CONCLUSIONS

Arecoline suppresses HaCaT cell viability by upregulating TPM1 through the TGF-β/Smad signalling pathway. This research provides a scientific basis for further study of arecoline and TPM1 in OSF and can be generalised to broader pharmacological studies. TPM1 may be a promising molecular target for treating OSF.

Genome-wide screening of abberant methylated drivers combined with relative risk loci in bladder cancer

Background

To explore important methylation‐driven genes (MDGs) and risk loci to construct risk model for prognosis of bladder cancer (BCa).

Methods

We utilized TCGA‐Assembler package to download 450K methylation data and corresponding transcriptome profiles. MethylMix package was used for identifying methylation‐driven genes and functional analysis was mainly performed based on ConsensusPathDB database. Then, Cox regression method was utilized to find prognostic MDGs, and we selected 17 hub genes via stepwise regression and multivariate Cox models. Kruskal‐Wallis test was implemented for comparisons between risk with other clinical variables. Moreover, we constructed the risk model and validated it in http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE13507. Gene set enrichment analysis was performed using the levels of risk score as the phenotype. Additionally, we further screened out the relative methylation sites associated with the 17 hub genes. Cox regression and Survival analysis were conducted to find the specifically prognostic sites.

Results

Two hundred and twenty‐eight MDGs were chosen by ConsensusPathDB database. Results revealed that most conspicuous pathways were transcriptional mis‐regulation pathways in cancer and EMT. After Cox regression analysis, 17 hub epigenetic MDGs were identified. We calculated the risk score and found satisfactory predictive efficiency by ROC curve (AUC = 0.762). In the validation group from http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE13507, 17 hub genes remained higher predictive value with AUC = 0.723 and patients in high‐risk group. Meanwhile, Kruskal‐Wallis test revealed that higher risk score correlated with a higher level of TNM stage, tumor grade, and advanced pathological stages. Then, identified 38 risk methylated loci that highly associated with prognosis. Last, gene set enrichment analysis revealed that high‐risk level of MDGs may correlate with several important pathways, including MAPK signaling pathway and so on.

Conclusion

Our study indicated several hub‐MDGs, calculated novel risk score and explored the prognostic value in BCa, which provided a promising approach to BCA prognosis assessment.

miRNA‑183‑5p.1 promotes the migration and invasion of gastric cancer AGS cells by targeting TPM1

MicroRNA-183 (miR-183) is a small, non-coding RNA that is involved in post-transcriptional processes, is upregulated in gastric cancer and acts as an oncogene in cancer migration. Although fragmentary reports have demonstrated the importance of miR-183 in gastric cancer, its biofunctions and regulatory effects are still unknown. In the present study, the gene and protein expression levels were determined by reverse transcription-quantitative PCR and western blot analysis. The connection between miR-183-5p.1 and tropomyosin 1 (TPM1) was tested through luciferase reporter experiments. Cell viability, apoptosis and related proteins were detected by MTT assay, flow cytometry, immunofluorescence and western blotting, respectively. The migration and invasion of AGS cells modulated by miR-183-5p.1 were analyzed by Transwell assay. TPM1 expression was found to be decreased in gastric cancer tissues and cell lines when compared with normal and adjacent tissues and gastric epithelial cells, and was regulated by miR-183-5p.1 targeting TPM1. miR-183-5p.1 overexpression facilitated the growth and suppressed the death of AGS cells through Bcl-2 and P53 proteins. In addition, miR-183-5p.1 restricted TPM1, TPM2 and TPM3 protein expression in AGS cells. The excessive levels of miR-183-5p.1 promoted the migration and invasion of AGS cells, and inhibited the apoptosis of AGS cells. However, the knockdown of miR-183-5p.1 induced the opposite in AGS cells. In conclusion, miR-183-5p.1 promotes cell proliferation, migration and invasion by downregulating TPM1 and deactivating the Bcl-2/P53 signaling pathways in gastric cancer, indicating that miR-183-5p.1 and TPM1 may be potential targets for the diagnosis or therapy of gastric cancer in the future.

Molecular integration of the anti-tropomyosin compound ATM-3507 into the coiled coil overlap region of the cancer-associated Tpm3.1

Tropomyosins (Tpm) determine the functional capacity of actin filaments in an isoform-specific manner. The primary isoform in cancer cells is Tpm3.1 and compounds that target Tpm3.1 show promising results as anti-cancer agents both in vivo and in vitro. We have determined the molecular mechanism of interaction of the lead compound ATM-3507 with Tpm3.1-containing actin filaments. When present during co-polymerization of Tpm3.1 with actin, ³H-ATM-3507 is incorporated into the filaments and saturates at approximately one molecule per Tpm3.1 dimer and with an apparent binding affinity of approximately 2 µM. In contrast, ³H-ATM-3507 is poorly incorporated into preformed Tpm3.1/actin co-polymers. CD spectroscopy and thermal melts using Tpm3.1 peptides containing the C-terminus, the N-terminus, and a combination of the two forming the overlap junction at the interface of adjacent Tpm3.1 dimers, show that ATM-3507 shifts the melting temperature of the C-terminus and the overlap junction, but not the N-terminus. Molecular dynamic simulation (MDS) analysis predicts that ATM-3507 integrates into the 4-helix coiled coil overlap junction and in doing so, likely changes the lateral movement of Tpm3.1 across the actin surface resulting in an alteration of filament interactions with actin binding proteins and myosin motors, consistent with the cellular impact of ATM-3507.

Tropomyosin-1 Functions as a Tumor Suppressor with Respect to Cell Proliferation, Angiogenesis and Metastasis in Renal Cell Carcinoma

Background: Tropomyosin-1 (TPM1) has long been known to be an actin-binding cytoskeletal protein. Multiple recent studies have revealed that TPM1 is down-regulated in various malignant tumors, including renal cell carcinoma (RCC). Methods: To further verify its role in RCC, transfection of a reconstructed plasmid was used to bi-directionally regulate TPM1 levels. A colony formation assay, tube formation assay and invasion assay were adopted to assess cell proliferation, angiogenesis and metastasis, respectively, in the 786-O and ACHN cell lines. The xenograft tumor sizes were measured, and the microvessel density (MVD) was quantified. Western blot and immunohistochemistry (IHC) were used to detect key proteins involved in these processes. Results: The colony formation assay and xenograft tumor models illustrated that TPM1 up-regulation inhibited RCC cell proliferation. The tube formation assay and detection of vascular endothelial growth factor (VEGF) and cluster of differentiation 34 (CD34) in xenografts revealed that TPM1 up-regulation inhibited angiogenesis in RCC. The invasion assay and detection of the E-cadherin and matrix metalloproteinases 9 (MMP-9) levels in xenografts demonstrated that TPM1 up-regulation inhibited tumor metastasis in RCC. Opposing effects were absent in TPM1 down-regulation models. Conclusions: TPM1 functions as a tumor suppressor with respect to cell proliferation, angiogenesis and metastasis in RCC, suggesting that it is a potential therapeutic target for advanced RCC.

Tropomyosins: Potential Biomarkers for Urothelial Bladder Cancer

Despite the incidence and prevalence of urothelial bladder cancer (UBC), few advances in treatment and diagnosis have been made in recent years. In this review, we discuss potential biomarker candidates: the tropomyosin family of genes, encoded by four loci in the human genome. The expression of these genes is tissue-specific. Tropomyosins are responsible for diverse cellular roles, most notably based upon their interplay with actin to maintain cellular processes, integrity and structure. Tropomyosins exhibit a large variety of splice forms, and altered isoform expression levels have been associated with cancer, including UBC. Notably, tropomyosin isoforms are detectable in urine, offering the potential for non-invasive diagnosis and risk-stratification. This review collates the basic knowledge on tropomyosin and its isoforms, and discusses their relationships with cancer-related phenomena, most specifically in UBC.

Long non-coding RNA MEG3 suppresses the development of bladder urothelial carcinoma by regulating miR-96 and TPM1

We aimed at investigating effects of long non-coding RNA maternally expressed 3 (MEG3) on the proliferation, cell cycle and apoptosis of bladder urothelial carcinoma cells and regulatory relationships among lncRNA MEG3, miR-96 and α-tropomyosin 1 (TPM1). Human clinical data from The Cancer Genome Atlas (TCGA) which contains bladder urothelial carcinoma tissues and adjacent tissues were used for analysis. The expression profiles of MEG3, miR-96, TPM1, cell cycle-related genes and apoptosis-related genes were examined by real-time quantitative polymerase chain reaction (RT-qPCR) and western blot. Regulating relationship among MEG3, miR-96 and TPM1 was confirmed by dual luciferase reporter assay. MTT assay and flow cytometry were performed to observe cell proliferation, cell cycle and apoptosis. The effects of lncRNA MEG3 on bladder urothelial carcinoma were confirmed both in vivo and in vitro. The mRNA expression and protein expression of MEG3, TPM1 were down-regulated in carcinoma tissues, whereas miR-96 expression was up-regulated. MEG3 overexpression resulted in miR-96 downregulation along with TPM1 upregulation, which inhibited cell proliferation and cell cycle but promoted cell apoptosis of bladder urothelial carcinoma cells in vitro, and at the same time inhibited tumor growth in vivo. In this process, expressions of apoptosis-related protein BCL2 associated X (Bax), cleaved-caspase 3 was up-regulated, whereas apoptosis regulator protein (Bcl-2) expression was suppressed when MEG3 was overexpressed, and cell cycle-related protein Cyclin D1 was down-regulated. LncRNA MEG3 low-expression promotes the proliferation and inhibits apoptosis of bladder urothelial carcinoma cells by regulating miR-96 along with TPM1.

Downregulated Expression of Tropomyosin 1 in Intrahepatic Cholangiocarcinoma: A Predictor of Recurrence and Prognosis

Background

The downregulation of tropomyosin 1 (TPM1) has been observed in various tumors, but few studies have focused on the clinical significance of TPM1 in intrahepatic cholangiocarcinoma (ICC). In the present study, we investigated the prognostic significance of TPM1 in ICC.

Material/Methods

A total of 124 patients with ICC were enrolled in this study. Quantitative real-time polymerase chain reaction (qRT-RCR) was performed to examine the mRNA levels of TPM1 in ICC tissue samples and adjacent noncancerous tissue specimens, while the protein level of TPM1 in tissue specimens were investigated using immunohistochemistry assay. The correlation of TPM1 with clinicopathological features of ICC was analyzed by chi-square test. Survival analysis was performed with Kaplan-Meier method. The Cox proportional hazards model was used to evaluate the prognostic value of TPM1 in patients with ICC.

Results

TPM1 expression was significantly downregulated in ICC tissues at mRNA and protein levels (P<0.001 for both). Downregulated TPM1 mRNA was negatively associated with tumor size (P=0.001) and TNM stage (P=0.007). Moreover, survival analysis demonstrated that patients with low TPM1 expression had a shorter overall survival (OS) (P<0.001) and recurrence-free survival (RFS) (P<0.001) than those with high TPM1 expression. Additionally, multivariate analysis showed that TPM1 could be a potential biomarker for predicting the recurrence (HR=4.632, 95% CI: 3.832–10.368, P<0.001) and survival outcome (HR=5.320, 95% CI: 2.627–11.776, P<0.001) of ICC.

Conclusions

TPM1 may serve as a useful biomarker for predicting tumor recurrence and prognosis in patients with ICC.

Considering the downregulation of Tpm1.6 and Tpm1.7 in squamous cell carcinoma of esophagus as a potent biomarker

AIM

Squamous cell carcinoma of esophagus (SCCE) is an aggressive disease with a poor prognosis. Tropomyosins attach to actin microfilaments, providing its stability. Nonmuscle cells express Tpm isoforms such as Tpm1.6 and Tpm1.7 which are involved in cytoskeleton functional properties regulation.

MATERIALS & METHODS

The expression of Tpm1.6 and Tpm1.7 was analyzed in SCCE tissues and its association with clinicopathological parameters and survival of patients was assessed.

RESULTS

Tpm1.6 and Tpm1.7, besides TPM1 mRNA decreased considerably in SCCE tissues relative to normal esophageal tissues (p < 0.001). TPM1 downregulation level was significantly associated with the degree of tumor differentiation (p = 0.017).

CONCLUSION

Tpm1.6 and Tpm1.7 suppression play a crucial role in esophagus tumorigenesis and could be associated with SCCE poor prognosis.

Tropomyosin-1 promotes cancer cell apoptosis via the p53-mediated mitochondrial pathway in renal cell carcinoma

Tropomyosin-1 (TPM1), a widely expressed actin-binding protein, is downregulated in many tumors and associated with cancer progression. A previous study from our group suggested that TPM1 could be involved in renal cell carcinoma (RCC) apoptosis, but the mechanisms and details remained unknown. The present study aimed to further examine the proapoptotic effects of TPM1 and investigate the underlying mechanisms in RCC cell lines. Results from cell viability, DAPI staining and apoptosis assays demonstrated that TPM1 upregulation inhibited cell proliferation and promoted cell apoptosis in both 786-O and ACHN RCC cell lines. However, TPM1 knockdown in the two RCC cell lines did not result in the opposite effects on cell proliferation or cell apoptosis. Comet assay and western blotting results demonstrated that TPM1 overexpression induced DNA damage and decreased the expression levels of the antiapoptotic factor BCL2 apoptosis regulator, while increasing the expression levels of the proapoptotic factors BCL2 associated X, Caspase-3 and p53 in 786-O and ACHN cells. The present findings suggest that TPM1 overexpression in RCC cell lines can induce tumor cell apoptosis via the p53-mediated mitochondrial pathway. Further studies are needed to fully elucidate the potential of TPM1 as a candidate for RCC targeted therapy in the future.

The clinical significance and biological function of tropomyosin 4 in colon cancer

Tropomyosin 4 (TPM4) has been found to be dys-regulated, and function as oncogene or anti-oncogene in human cancers. However, there was no report on the clinical significance and biological function of TPM4 in colon cancer. This study was designed to investigate the clinical value and biological function of TPM4 in colon cancer. Thus, we detected the TPM4 expression in colon cancer clinical samples, and conducted the gain-of-function in colon cancer cell lines. In our results, TPM4 mRNA and protein expressions were reduced in colon cancer tissues and cell lines compared with normal colon tissues and colon epithelial cell line, respectively. TPM4 protein low-expression was obviously associated with clinical stage, T classification (invasion depth), N classification (lymph node metastasis), distant metastasis and differentiation. Survival analysis showed low-expression of TPM4 was an unfavorable independent prognostic factor for colon cancer patients. Moreover, the experiments in vitro suggested up-regulated TPM4 expression suppressed colon cancer cell migration, invasion and metastasis-associated gene expression including MMP-2, MMP-9 and MT1-MMP, but had no effect on cell proliferation. In conclusion, TPM4 is associated with clinical progression in colon cancer patient and acts as a tumor suppressor in colon cancer cell.

Global Quantitative Proteomics reveal Deregulation of Cytoskeletal and Apoptotic Signalling Proteins in Oral Tongue Squamous Cell Carcinoma

Oral malignancies remain to have higher morbidity and mortality rates owing to the poor understanding of the carcinogenesis and the lack of early detection and diagnosis. The lack of established biomarkers for oral tongue squamous cell carcinoma (OTSCC) resulted in aggressive multi-modality management less effective. Here, we report for the first time that a panel of potential markers identified from tongue tumor samples using two-dimensional-differential-in-gel-electrophoresis (2D-DIGE). Our approach of combining 2D-DIGE with tandem mass spectrometry identified 24 candidate proteins including cofilins, myosin light chain family members, annexins, serpins, HSPs and tropomyosins, with significant differential expression in tongue carcinomas as compared with their matched adjacent normal tissues. The expression levels of the identified proteins were further validated in larger cohort of Indian samples using qPCR. Most of the differentially regulated proteins are involved in actin cytoskeletal dynamics, drug resistance, immune system, inflammation and apoptotic signalling pathways and are known to play critical role in oral tumorigenesis. Taken together, the results from present investigation provide a valuable base for understanding the development and progression of OTSCC. The validated panel of proteins may be used as potential biomarkers for early detection as well as in predicting therapeutic outcome of OTSCC.

Tropomyosin-1 acts as a potential tumor suppressor in human oral squamous cell carcinoma

It is widely accepted that oral squamous cell carcinoma (OSCC) is a major contributor to the incidence and mortality of neck and head cancer. Tropomyosin-1 (TPM1), which is expressed at a low level, has been considered a prominent tumor-suppressing gene in a variety of solid tumors, although the precise mechanism of the TPM1 gene in OSCC progression remains unknown. We found that TPM1 expression levels decreased in OSCC patients and OSCC cell lines. The overall and cancer-specific survival of patients who exhibited low TPM1 levels were inferior to those of patients who had high TPM1 levels. It was also found that OSCC patients who suffered from disease stageⅠ-Ⅱ were more likely to have an up-regulated TPM1 expression level, and OSCC patients with lymph node metastasis had a higher probability of exhibiting reduced TPM1 expression. We show that overexpression of TPM1 can promote cell apoptosis and inhibit migration. Our results suggest that TPM1 can suppress tumors in OSCC, and the TPM1 expression level is related to OSCC patient prognosis.

Hypoxia and hyperoxia differentially control proliferation of rat neural crest stem cells via distinct regulatory pathways of the HIF1α-CXCR4 and TP53-TPM1 proteins

BACKGROUND

Neural crest stem cells (NCSCs) are a population of adult multipotent stem cells. We are interested in studying whether oxygen tensions affect the capability of NCSCs to self-renew and repair damaged tissues. NCSCs extracted from the hair follicle bulge region of the rat whisker pad were cultured in vitro under different oxygen tensions.

RESULTS

We found significantly increased and decreased rates of cell proliferation in rat NCSCs (rNCSCs) cultured, respectively, at 0.5% and 80% oxygen levels. At 0.5% oxygen, the expression of both hypoxia-inducible factor (HIF) 1α and CXCR4 was greatly enhanced in the rNCSC nuclei and was suppressed by incubation with the CXCR4-specific antagonist AMD3100. In addition, the rate of cell apoptosis in the rNCSCs cultured at 80% oxygen was dramatically increased, associated with increased nuclear expression of TP53, decreased cytoplasmic expression of TPM1 (tropomyosin-1), and increased nuclear-to-cytoplasmic translocation of S100A2. Incubation of rNCSCs with the antioxidant N-acetylcysteine (NAC) overcame the inhibitory effect of 80% oxygen on proliferation and survival of rNCSCs.

CONCLUSIONS

Our results show for the first time that extreme oxygen tensions directly control NCSC proliferation differentially via distinct regulatory pathways of proteins, with hypoxia via the HIF1α-CXCR4 pathway and hyperoxia via the TP53-TPM1 pathway. Developmental Dynamics 246:162-185, 2017. © 2016 Wiley Periodicals, Inc.