Harnessing function of EMT in cancer drug resistance: a metastasis regulator determines chemotherapy response

Epithelial-mesenchymal transition (EMT) is a complicated molecular process that governs cellular shape and function changes throughout tissue development and embryogenesis. In addition, EMT contributes to the development and spread of tumors. Expanding and degrading the surrounding microenvironment, cells undergoing EMT move away from the main location. On the basis of the expression of fibroblast-specific protein-1 (FSP1), fibroblast growth factor (FGF), collagen, and smooth muscle actin (-SMA), the mesenchymal phenotype exhibited in fibroblasts is crucial for promoting EMT. While EMT is not entirely reliant on its regulators like ZEB1/2, Twist, and Snail proteins, investigation of upstream signaling (like EGF, TGF-β, Wnt) is required to get a more thorough understanding of tumor EMT. Throughout numerous cancers, connections between tumor epithelial and fibroblast cells that influence tumor growth have been found. The significance of cellular crosstalk stems from the fact that these events affect therapeutic response and disease prognosis. This study examines how classical EMT signals emanating from various cancer cells interfere to tumor metastasis, treatment resistance, and tumor recurrence.

The Immunohistochemical Expression of Epithelial-Mesenchymal Transition Markers in Precancerous Lesions and Cervical Cancer

In the epithelial-mesenchymal transition (EMT) process, cells lose their epithelial phenotype and gain mesenchymal features. This phenomenon was observed in the metastatic phase of neoplastic diseases, e.g., cervical cancer. There are specific markers that are expressed in the EMT. The aim of this study was to determine the localization of and associations between the immunohistochemical (IHC) expression of TWIST, SNAIL, and SLUG proteins in precancerous lesions and cervical cancer. The IHC analysis disclosed higher expressions of EMT markers in precancerous lesions and cervical cancer than in the control group. Moreover, stronger expression of TWIST, SNAIL, and SLUG was observed in cervical intraepithelial neoplasia grade 3 (CIN3) vs. CIN1, CIN3 vs. CIN2, and CIN2 vs. CIN1 cases (p < 0.05). In cervical cancer, IHC reactions demonstrated differences in TWIST, SNAIL, and SLUG expression in grade 1 (G1) vs. grade 2 (G2) (p < 0.0011; p < 0.0017; p < 0.0001, respectively) and in G1 vs. grade 3 (G3) (p < 0.0029; p < 0.0005; p < 0.0001, respectively). The results of our study clearly showed that existing differences in the expression of the tested markers in precancerous vs. cancerous lesions may be utilized in the diagnosis of cervical cancer. Further studies on bigger populations, as well as in comparison with well-known markers, may improve our outcomes.

A tumor metastasis-associated molecule TWIST1 is a favorable target for cancer immunotherapy due to its immunogenicity

Although neoantigens are one of the most favorable targets in cancer immunotherapy, it is less versatile and costly to apply neoantigen-derived cancer vaccines to patients due to individual variation. It is, therefore, important to find highly immunogenic antigens among tumor-specific or associated antigens, which are shared among patients. Considering the cancer immunoediting theory, immunogenic tumor cells cannot survive in early phase of tumor progression including two processes: elimination and equilibrium. We hypothesized that highly immunogenic molecules are allowed to be expressed in tumor cells after immune suppressive tumor microenvironment was established, if these molecules contribute to tumor survival. In the current study, we focused on TWIST1 as a candidate of highly immunogenic antigens because it is upregulated in tumor cells under hypoxia and promotes tumor metastasis, which are observed in late phase of tumor progression. We demonstrated that TWIST1 had an immunogenic peptide sequence TWIST1_140-162 , which effectively activated TWIST1-specific CD4⁺ T-cells. In a short-term culture system, we detected more TWIST1-specific responses in breast cancer patients than in healthy donors. Vaccination with the TWIST1 peptide also showed efficient expansion of TWIST1-reactive HTLs in humanized mice. These findings indicate that TWIST1 is a highly immunogenic shared antigen and a favorable target for cancer immunotherapy.

Downregulation of LNMAS orchestrates partial EMT and immune escape from macrophage phagocytosis to promote lymph node metastasis of cervical cancer

Epithelial-mesenchymal transition (EMT) is an essential step to drive the metastatic cascade to lymph nodes (LNs) in cervical cancer cells. However, few of them metastasize successfully partially due to increased susceptibility to immunosurveillance conferred by EMT. The precise mechanisms of cancer cells orchestrate EMT and immune evasion remain largely unexplored. In this study, we identified a lncRNA termed lymph node metastasis associated suppressor (LNMAS), which was downregulated in LN-positive cervical cancer patients and correlated with LN metastasis and prognosis. Functionally, LNMAS suppressed cervical cancer cells metastasis in vitro and in vivo. Mechanistically, LNMAS exerts its metastasis suppressive activity by competitively interacting with HMGB1 and abrogating the chromatin accessibility of TWIST1 and STC1, inhibiting TWIST1-mediated partial EMT and STC1-dependent immune escape from macrophage phagocytosis. We further demonstrated that the CpG sites in the promoter region of LNMAS was hypermethylated and contributed to the downregulation of LNMAS. Taken together, our results reveal the essential role of LNMAS in the LN metastasis of cervical cancer and provide mechanistic insights into the regulation of LNMAS in EMT and immune evasion.

B7-H4 Expression in Precancerous Lesions of the Uterine Cervix

Over 10% of patients diagnosed with cervical intraepithelial neoplasia (CIN) have no lesions detected in their cervical conization specimens. The purpose of this study was to determine the factors related to the absence of such lesions. We particularly sought to investigate whether the expression of B7-H4 in precancerous lesions and cancer of the uterine cervix plays a role in the presence or absence of residual lesions in conization specimens and whether this protein is associated with T cells (i.e., Foxp3⁺ regulatory T cells, CD4⁺, and CD8⁺) and interferon-γ production. Of the 807 patients with CIN treated by conization, 104 (12.9%) had no lesions in their conization specimens. Seventy-five of these patients were deemed the study group and were matched with 75 patients who did have CIN detected in their conization specimens (the control group). Immunohistochemistry and immunofluorescence staining were used to detect B7-H4, Foxp3, CD4, CD8, and interferon-γ in the 75 pairs of specimens obtained via biopsy; 20 samples were found to have chronic cervicitis, and another 20 had squamous cell carcinoma of the cervix. Menopause, the absence of human papillomavirus, low-grade histological findings, and a diagnosis of CIN1 and CIN2 on biopsy correlated with a low probability of lesions on conization specimens. B7-H4 expression was detected in 11.1% of CIN2, 46.6% of CIN3, and 70% of cervical cancer samples, but not in tissues representing chronic cervicitis or CIN1. B7-H4 expression was associated with the presence of lesions on conization specimens, increased regulatory T cells, decreased CD8⁺ T cells, and lower interferon-γ production. These data suggest that close follow-up and thorough reevaluation should be considered for patients diagnosed with CIN2 who are negative for B7-H4 expression on biopsy before proceeding with cervical conization.

Immunohistochemical and genetic characteristics of HPV-associated endocervical carcinoma with an invasive stratified mucin-producing carcinoma (ISMC) component

Invasive stratified mucin-producing carcinoma (ISMC) is a recently described entity of human papillomavirus (HPV)-associated endocervical adenocarcinoma with phenotypic plasticity and aggressive clinical behavior. To identify the cell of origin of ISMC, we investigated the immunohistochemical expression of cervical epithelial cell markers (CK7, PAX8, CK5/6, p63, and CK17), stemness markers (ALDH1 and Nanog), and epithelial-mesenchymal transition (EMT) markers (Snail, Twist, and E-cadherin) in 10 pure and mixed type ISMCs with at least 10% of ISMC component in the entire tumor, seven usual type endocervical adenocarcinomas (UEAs), and seven squamous cell carcinomas (SCCs). In addition, targeted sequencing was performed in 10 ISMCs. ISMC was significantly associated with larger tumor size (p = 0.011), more frequent lymphovascular invasion and lymph node metastasis (p < 0.001), higher FIGO stage (p = 0.022), and a tendency for worse clinical outcomes (p = 0.056) compared to other HPV-associated subtypes. ISMC showed negative or borderline positivity for PAX8, CK5/6, and p63, which were distinct from UEA and SCC (p < 0.01). Compared to UEA and SCC, ISMC showed higher expression for ALDH1 (p = 0.119 for UEA and p = 0.009 for SCC), Snail (p = 0.036), and Twist (p = 0.119), and tended to show decreased E-cadherin expression (p = 0.083). In next-generation sequencing analysis, ISMC exhibited frequent STK11, MET, FANCA, and PALB2 mutations compared to conventional cervical carcinomas, and genes related to EMT and stemness were frequently altered. EMT-prone and stemness characteristics and peripheral expression of reserve cell and EMT markers of ISMC suggest its cervical reserve cell origin. We recommend PAX8, CK5/6, and p63 as diagnostic triple biomarkers for ISMC. These findings highlight the distinct biological basis of ISMC.

Identification of Clinical Relevant Molecular Subtypes of Pheochromocytoma

Pheochromocytoma (PCC) is a rare neuroendocrine tumor of the adrenal gland with a high rate of mortality if diagnosed at a late stage. Common symptoms of pheochromocytoma include headache, anxiety, palpitation, and diaphoresis. Different treatments are under observation for PCC but there is still no effective treatment option. Recently, the gene expression profiling of various tumors has provided new subtype-specific options for targeted therapies. In this study, using data sets from TCGA and the GSE19422 cohorts, we identified two distinct PCC subtypes with distinct gene expression patterns. Genes enriched in Subtype I PCCs were involved in the dopaminergic synapse, nicotine addiction, and long-term depression pathways, while genes enriched in subtype II PCCs were involved in protein digestion and absorption, vascular smooth muscle contraction, and ECM receptor interaction pathways. We further identified subtype specific genes such as ALK, IGF1R, RET, and RSPO2 for subtype I and EGFR, ESR1, and SMO for subtype II, the overexpression of which led to cell invasion and tumorigenesis. These genes identified in the present research may serve as potential subtype-specific therapeutic targets to understand the underlying mechanisms of tumorigenesis. Our findings may further guide towards the development of targeted therapies and potential molecular biomarkers against PCC.

The role of epithelial-mesenchymal transition in regulating radioresistance

Cancer patients with different stages can benefit from radiotherapy, but there are still limited due to inherent or acquired radioresistance. The epithelial-mesenchymal transition (EMT) is a complex biological process that is implicated in malignant characteristics of cancer, such as radioresistance. Although the possible mechanisms of EMT-dependent radioresistance are being extensively studied, there is a lack of a clear picture of the overall signaling of EMT-mediated radioresistance. In this review, we highlight the role and possible molecular mechanisms of EMT in cancer radioresistance, in particular to EMT-associated signaling pathway, EMT-inducing transcription factors (EMT-TFs), EMT-related non-coding RNAs. The knowledge of EMT-associated mechanisms of radioresistance will offer more potent therapy targets to improve the radiotherapy responses.

Roles of the Phosphorylation of Transcriptional Factors in Epithelial-Mesenchymal Transition

Epithelial-to-mesenchymal transition (EMT) is the first step in the development of the invasive and migratory properties of cancer metastasis. Since the transcriptional reprogramming of a number of genes occurs in EMT, the regulation of EMT transcription factors has been intensively investigated. EMT transcriptional factors are commonly classified by the direct or indirect repression of E-cadherin because one of hallmarks of EMT is the loss of E-cadherin. This facilitates the expression of genes for EMT, tumor invasion, and metastasis. The posttranslational modification of EMT transcriptional factors, such as Snail and Slug, directly regulates their functions, including their stability, nuclear localization, protein-protein interaction, and ubiquitination for the promotion or termination of EMT at the specific points. Here, we discuss how posttranslational modifications regulate gene expression in a dynamic and reversible manner by modifying upstream signaling pathways, focusing in particular on the posttranslational modifications of Snail, Slug, ZEB1, ZEB2, and TWIST1. This review demonstrates that EMT transcription factors regulate metastasis through their posttranslational modifications and that the flexibility and reversibility of EMT can be modified by phosphorylation.

AKT-ions with a TWIST between EMT and MET

The transcription factor Twist is an important regulator of cranial suture during embryogenesis. Closure of the neural tube is achieved via Twist-triggered cellular transition from an epithelial to mesenchymal phenotype, a process known as epithelial-mesenchymal transition (EMT), characterized by a remarkable increase in cell motility. In the absence of Twist activity, EMT and associated phenotypic changes in cell morphology and motility can also be induced, albeit moderately, by other transcription factor families, including Snail and Zeb. Aberrant EMT triggered by Twist in human mammary tumour cells was first reported to drive metastasis to the lung in a metastatic breast cancer model. Subsequent analysis of many types of carcinoma demonstrated overexpression of these unique EMT transcription factors, which statistically correlated with worse outcome, indicating their potential as biomarkers in the clinic. However, the mechanisms underlying their activation remain unclear. Interestingly, increasing evidence indicates they are selectively activated by distinct intracellular kinases, thereby acting as downstream effectors facilitating transduction of cytoplasmic signals into nucleus and reprogramming EMT and mesenchymal-epithelial transition (MET) transcription to control cell plasticity. Understanding these relationships and emerging data indicating differential phosphorylation of Twist leads to complex and even paradoxical functionalities, will be vital to unlocking their potential in clinical settings.

Combined detection of Twist1, Snail1 and squamous cell carcinoma antigen for the prognostic evaluation of invasion and metastasis in cervical squamous cell carcinoma

BACKGROUND

Cervical cancer is one of the most common malignant tumours of the female reproductive system, ranking second only to breast cancer in morbidity worldwide. Essential features of the progression of cervical cancer are invasion and metastasis, which are closely related to disease prognosis and mortality rate. At the present time there is no effective method to evaluate cancer invasion and metastasis before surgery. Here we report our study on molecular changes in biopsy tissue for the prognostic evaluation of cancer invasion and metastasis.

PATIENTS AND METHODS

Expression of the epithelial-mesenchymal transition-inducing transcription factors Twist1 and Snail1 was detected by immunohistochemistry in 32 normal, 36 low-grade squamous intraepithelial neoplasia (LSIL), 54 high-grade squamous intraepithelial neoplasia (HSIL) and 320 cervical squamous cell carcinoma (CSCC) samples. The correlation between the expression of Twist1, Snail1 and squamous cell carcinoma antigen (SCCA) in CSCC tissues and clinical pathology results was evaluated. A transwell migration and invasion assay was used to explore the roles of Twist1 and Snail1 in the invasion of cancer cells. Lymph node metastasis and lymphovascular space invasion (LVSI) rates for the following groups were analysed: SCCA(+) group, Twist1(+) group, Snail1(+) group, Twist1(+)Snail1(+)group, Twist1(+)SCCA(+)group, Snail1(+)SCCA(+)group and Twist1(+)Snail1(+)SCCA(+) group.

RESULTS

The expression of Twist1 and Snail1 was significantly upregulated in HSIL and CSCC (p < 0.05). Twist1 and Snail1 expression levels were associated with LVSI, lymph node metastasis and histological grade (p < 0.05) but not with age or FIGO stage (p > 0.05). The expression of SCCA was associated with LVSI, lymph node metastasis, FIGO stage and histological grade (p < 0.05) but not with age (p > 0.05). Twist1 was an independent factor contributing to the invasion ability of cervical cancer cells. In addition, the positive rate of lymph node metastasis and LVSI was higher in the Twist1(+)Snail1(+)SCCA(+) group than in the SCCA(+) group, Twist1(+) group and Snail1(+) group, respectively (p < 0.05).

CONCLUSION

Combined detection of Twist1 and Snail1 in SCCA-positive biopsy specimens may be a potential method for evaluating the invasion and metastasis of CSCC prior to surgery.

Smoking and gender modify the effect of TWIST on patient survival in head and neck squamous carcinoma

PURPOSE

TWIST is a critical factor for predicting prognosis in several human cancers. Here, we study the prognostic significance of TWIST1 and TWIST2 in Head and Neck squamous cell carcinoma (HNSCC) as well as interactions of TWISTs with both gender and smoking in patient survival.

METHODS

upper quartile normalized RNA-seq V2 RSEM values of TWIST1 and TWIST2 expressions were retrieved from a TCGA HNSCC dataset. Kaplan-Meier survival curves were used to assess the associations of TWIST1 and TWIST2 with patient survival, and multivariate Cox proportional hazards regression models were used to estimate the hazards ratios (HRs) and their 95% confidence intervals (CIs).

RESULTS

Survival analyses showed that high TWIST1 expression was associated with a poor overall survival at a borderline significance level, while a superior but not statistically significant overall survival was observed in high TWIST2 expression. The multivariate Cox proportional hazards regression model showed a significantly elevated risk of death (HR=1.37, p = 0.038) in patients with high TWIST1 compared to low TWIST1, and a borderline significantly decreased risk of death (HR = 0.74, p = 0.055) in patients with high TWIST2 compared to low TWIST2. Further stratification analyses showed that increased risks of death were found significantly in male and borderline significantly in smoker patients with high TWIST1 compared to low one, and a significantly decreased risk of death in non-smoker patients with high TWIST2 compared to low one.

CONCLUSIONS

TWIST1 and TWIST2 are differentially associated with HNSCC patient survival. Gender and smoking could modify the effect of TWISTs on the risk of death in HNSCC patients.

Multiple biological functions of Twist1 in various cancers

Twist1 is a well-known regulator of transcription during embryonic organogenesis in many species. In humans, Twist1 malfunction was first linked to Saethre-Chotzen syndrome and later identified to play an essential role in tumor initiation, stemness, angiogenesis, invasion, metastasis, and chemo-resistance in a variety of carcinomas, sarcomas, and hematological malignances. In this review, we will first focus on systematically elaborating the diverse pathological functions of Twist1 in various cancers, then delineating the intricate underlying network of molecular mechanisms, based on which we will summarize current therapeutic strategies in cancer treatment that target and modulate Twist1-involved signaling pathways. Most importantly, we will put special emphasis on revealing the independence and interdependency of these multiple biological functions of Twist1, piecing together the whole delicate picture of Twist1's diversified pathological roles in different cancers and providing new perspectives to guide future research.

Twist1 Enhances Hypoxia Induced Radioresistance in Cervical Cancer Cells by Promoting Nuclear EGFR Localization

Twist1 is a crucial transcription factor that regulates epithelial mesenchymal transition and involves in metastasis. Recent evidence suggests that Twist1 plays important role in hypoxia-induced radioresistance, but the underlying mechanism remains elusive. Here we investigated the change of Twist1 expression in human cervical squamous cancer cell line SiHa after hypoxia treatment. We also explored the role of Twist1 in radioresistance by manipulating the expression level of Twist1. We observed that hypoxia treatment elevated the expression of Twist1 in SiHa cells. Knockdown of Twist1 with siRNA increased the radiosensitivity of SiHa cells under hypoxia condition, accompanied by reduced levels of nuclear Epidermal Growth Factor Receptor (EGFR) and DNA-dependent protein kinase (DNA-PK). Conversely, overexpression of Twist1 led to increased radioresistance of SiHa cells, which in turn increased nuclear EGFR localization and expression levels of nuclear DNA-PK. Moreover, concomitant high expression of hypoxia-inducible factor-1α (HIF-1α) and Twist1 in primary tumors of cervical cancer patients correlated with the worse prognosis after irradiation treatment. Taken together, these data provide new insights into molecular mechanism underlying hypoxia-induced radioresistance in cervical cancer cells, and suggest that Twist1 is a promising molecular target to improve the efficacy of cancer radiotherapy.

ARHGAP1 overexpression inhibits proliferation, migration and invasion of C-33A and SiHa cell lines

ARHGAP1, also known as RhoGAP, RhoGAP1, CDC42GAP and p50rhoGAP, is officially named Ras homology (Rho) GTPase-activating protein 1, which is one of the key members of RhoGAPs. Growing evidences demonstrate that several RhoGAPs are suppressed or downregulated in cancers. Thus, the aim of this study was to explore the effects of ARHGAP1 on cervical carcinoma cells. The human cervical carcinoma cells C-33A and SiHa were transduced with lentivirus targeting ARHGAP1 (lenti-ARHGAP1). Cellular proliferation, migration and invasion assays, as well as quantitative real-time polymerase chain reaction and Western blot assays, were performed in the control, negative control (infected with lentivirus) and ARHGAP1+-infected groups. Results showed that overexpression of ARHGAP1 markedly inhibited the proliferation of both C-33A and SiHa cells at 24 h, 48 h and 72 h in a time-dependent manner (n=3, P<0.01). Migration and invasion of C-33A and SiHa cells were suppressed after the transduction with lenti-ARHGAP1 compared with the controls (n=3, P<0.01). In addition, several tumor cellular process-related proteins, such as matrix metallopeptidase 2, zinc finger E-box binding homeobox 1, Cyclin B1, twist family bHLH transcription factor 1 and proliferating cell nuclear antigen, were all downregulated in ARHGAP1-overexpressed C-33A and SiHa cells and proved to be targets of ARHGAP1. This study indicated that ARHGAP1 may have a positive function on antitumor activity in the treatment of cervical cancer.

The relationship between platinum drug resistance and epithelial-mesenchymal transition

One of the most commonly used chemotherapeutics, platinum drugs are used to treat a wide range of cancer types. Although many cancers initially respond well to those drugs, drug resistance occurs frequently and different molecular mechanisms have been associated with it. However, predictive biomarkers of cellular response in specific tumour types still do not exist. Epithelial-mesenchymal transition (EMT) is a malignant cancer phenotype characterized by aggressive invasion and metastasis, and resistance to apoptosis. Recent studies indicate that EMT accompanies the development of drug resistance to a number of cancer chemotherapies. The link between these two phenomena is still not elucidated, although several important molecules involved in both these complex processes, such as transcription factors (SNAIL, TWIST, ZEB, etc.) and miRNAs (miRNA-200 family, miR-15, miR-186, etc.) have been recognized as important. This article reviews numerous unresolved issues regarding platinum drugs resistance and EMT, the complexity of the signalling networks that regulate those two phenomena and their importance in tumour response and spreading which are becoming focuses of interest of many scientists. This article also presents molecules involved in platinum resistance and EMT as possible targets for new cancer therapy.

microRNA-145 modulates epithelial-mesenchymal transition and suppresses proliferation, migration and invasion by targeting SIP1 in human cervical cancer cells

PURPOSE

Previously, it has been reported that microRNA-145 (miR-145) is lowly expressed in human cervical cancers and that its putative tumour suppressive role may be attributed to epithelial-mesenchymal transition (EMT) regulation. Here, we aimed to assess whether miR-145 may affect EMT-associated markers/genes and suppress cervical cancer growth and motility, and to provide a mechanistic basis for these phenomena.

METHODS

The identification of the SMAD-interacting protein 1 (SIP1) mRNA as putative miR-145 target was investigated using a 3' untranslated region (3'UTR) luciferase assay and Western blotting, respectively. The functional effects of exogenous miR-145 expression, miR-145 suppression or siRNA-mediated SIP1 expression down-regulation in cervical cancer-derived C33A and SiHa cells were analysed using Western blotting, BrdU incorporation (proliferation), transwell migration and invasion assays. In addition, the expression levels of miR-145 and SIP1 were determined in primary human cervical cancer and non-cancer tissue samples using qRT-PCR.

RESULTS

We found that miR-145 binds to the wild-type 3'UTR of SIP1, but not to its mutant counterpart, and that, through this binding, miR-145 can effectively down-regulate SIP1 expression. In addition, we found that exogenous miR-145 expression or siRNA-mediated down-regulation of SIP1 expression attenuates the proliferation, migration and invasion of C33A and SiHa cells and alters the expression of the EMT-associated markers CDH1, VIM and SNAI1, whereas inhibition of endogenous miR-145 expression elicited the opposite effects. The expression of miR-145 in cervical cancer tissue samples was found to be low, while that of SIP1 was found to be high compared to non-cancerous cervical tissues. An inverse expression correlation between the two was substantiated through the anlaysis of data deposited in the TCGA database.

CONCLUSION

Our data indicate that low miR-145 expression levels in conjunction with elevated SIP1 expression levels may contribute to cervical cancer development. MiR-145-mediated regulation of SIP1 provides a novel mechanistic basis for its tumour suppressive mode of action in human cervical cancer cells.

Human papillomavirus oncoproteins differentially modulate epithelial-mesenchymal transition in 5-FU-resistant cervical cancer cells

Etiological role of viral proteins E6 and E7 of high-risk HPV in cervical carcinogenesis is well established. However, their contribution in chemoresistance and epithelial-mesenchymal transition (EMT) that leads to advanced metastatic lesions and chemoresistance is poorly defined. In the present study, contribution of viral oncoproteins in acquisition of EMT character during onset of chemoresistance was assessed. A chemoresistant cell line (SiHaCR) was developed from an established HPV16-positive cervical cancer cell line, SiHa, by escalating selection pressure of 5-fluorouracil (5-FU). Expression of Survivin, ABCG2, Snail, Slug, Twist, and Vimentin was examined in SiHa and SiHaCR cells by reverse transcriptase-PCR (RT-PCR) and immunoblotting assays. Mesenchymal phenotype in SiHaCR cells was confirmed by assessment of migration and invasion potentials. SiHaCR cells displayed elevated level of functional and molecular markers associated with chemoresistance (Survivin, ABCG2) and EMT (Snail, Slug, Twist, Vimentin) and reduced E-cadherin. SiHaCR also showed increased levels of HPV16 E6 and E7 transcripts. Specific silencing of HPV16 E6, but not E7 using corresponding siRNA, demonstrated a differential involvement of HPV oncogenes in manifestation of EMT. HPV16 E6 silencing resulted in reduction of Slug and Twist expression. However, the expression of Snail and Vimentin was only marginally affected. In contrast, there was an increase in the expression of E-cadherin. A reduced migration and invasion capabilities were observed only in E6-silenced SiHaCR cells, which further confirmed functional contribution of HPV16 E6 in manifestation of EMT. Taken together, our study demonstrated an active involvement of HPV16 E6 in regulation of EMT, which promotes chemoresistance in cervical cancer.

The Small C-terminal Domain Phosphatase 1 Inhibits Cancer Cell Migration and Invasion by Dephosphorylating Ser(P)68-Twist1 to Accelerate Twist1 Protein Degradation

Twist1 is a basic helix-loop-helix transcription factor that strongly promotes epithelial-to-mesenchymal transition, migration, invasion, and metastasis of cancer cells. The MAPK-phosphorylated Twist1 on its serine 68 (Ser(P)(68)-Twist1) has a significantly enhanced stability and function to drive cancer cell invasion and metastasis. However, the phosphatase that dephosphorylates Ser(P)(68)-Twist1 and destabilizes Twist1 has not been identified and characterized. In this study, we screened a serine/threonine phosphatase cDNA expression library in HEK293T cells with ectopically coexpressed Twist1. We found that the small C-terminal domain phosphatase 1 (SCP1) specifically dephosphorylates Ser(P)(68)-Twist1 in both cell-free reactions and living cells. SCP1 uses its amino acid residues 43-63 to interact with the N terminus of Twist1. Increased SCP1 expression in cells decreased Ser(P)(68)-Twist1 and total Twist1 proteins, whereas knockdown of SCP1 increased Ser(P)(68)-Twist1 and total Twist1 proteins. Furthermore, the levels of SCP1 are negatively correlated with Twist1 protein levels in several cancer cell lines. SCP1-dephosphorylated Twist1 undergoes fast degradation via the ubiquitin-proteasome pathway. Importantly, an increase in SCP1 expression in breast cancer cells with either endogenous or ectopically expressed Twist1 largely inhibits the Twist1-induced epithelial-to-mesenchymal transition phenotype and the migration and invasion capabilities of these cells. These results indicate that SCP1 is the phosphatase that counterregulates the MAPK-mediated phosphorylation of Ser(68)-Twist1. Thus, an increase in SCP1 expression and activity may be a useful strategy for eliminating the detrimental roles of Twist1 in cancer cells.

Epithelial to Mesenchymal Transition in a Clinical Perspective. J Oncol. 2015;2015:792182. [PMID: 26425122 DOI: 10.1155/2015/792182]

Tumor growth and metastatic dissemination rely on cellular plasticity. Among the different phenotypes acquired by cancer cells, epithelial to mesenchymal transition (EMT) has been extensively illustrated. Indeed, this transition allows an epithelial polarized cell to acquire a more mesenchymal phenotype with increased mobility and invasiveness. The role of EMT is quite clear during developmental stage. In the neoplastic context in many tumors EMT has been associated with a more aggressive tumor phenotype including local invasion and distant metastasis. EMT allows the cell to invade surrounding tissues and survive in the general circulation and through a stem cell phenotype grown in the host organ. The molecular pathways underlying EMT have also been clearly defined and their description is beyond the scope of this review. Here we will summarize and analyze the attempts made to block EMT in the therapeutic context. Indeed, till today, most of the studies are made in animal models. Few clinical trials are ongoing with no obvious benefits of EMT inhibitors yet. We point out the limitations of EMT targeting such tumor heterogeneity or the dynamics of EMT during disease progression.

Twist-related protein 1-mediated regulation of mesenchymal change contributes to the migration and invasion of cervical cancer cells

Twist-related protein 1 (Twist1), is a class II basic helix-loop-helix transcription factor, which has been demonstrated to be a major regulator of epithelial-mesenchymal transition (EMT), and therefore is involved in promoting carcinoma metastasis. Previous studies have demonstrated that Twist1 expression is upregulated in cervical cancer cases with poor clinical outcomes. However, the mechanisms that mediate the role of Twist1 in cervical cancer metastasis are poorly understood. To the best of our knowledge, the present study provides the first evidence that the downregulation of Twist1 by short hairpin RNA lentivirus (LV-shRNA) resulted in the inhibition of invasion and migration of cervical cancer cells. Furthermore, the present study presents evidence that reducing Twist1 expression prevents cervical cancer cells from undergoing EMT. The expression of the epithelial cell marker, E-cadherin, was elevated; and the expression levels of mesenchymal cell markers [fibronectin, vimentin, matrix metalloproteinase-9 (MMP-9) and MMP-2] were reduced in the LV-sh-Twist1 group in cervical cells. Collectively, these findings indicate that Twist1-mediated modulation of EMT is important in the invasion and migration of cervical cells, and also indicates the potential therapeutic importance of strategies involving the inactivation of Twist1-mediated mesenchymal changes in cervical cancer.

EMT-Inducing Molecular Factors in Gynecological Cancers

Gynecologic cancers are the unregulated growth of neoplastic cells that arise in the cervix, ovaries, fallopian tubes, uterus, vagina, and vulva. Although gynecologic cancers are characterized by different signs and symptoms, studies have shown that they share common risk factors, such as smoking, obesity, age, exposure to certain chemicals, infection with human immunodeficiency virus (HIV), and infection with human papilloma virus (HPV). Despite recent advancements in the preventative, diagnostic, and therapeutic interventions for gynecologic cancers, many patients still die as a result of metastasis and recurrence. Since mounting evidence indicates that the epithelial-mesenchymal transition (EMT) process plays an essential role in metastatic relapse of cancer, understanding the molecular aberrations responsible for the EMT and its underlying signaling should be given high priority in order to reduce cancer morbidity and mortality.

The key role of astrocyte elevated gene-1 in CCR6-induced EMT in cervical cancer

In recent years, astrocyte elevated gene-1 (AEG-1) has been recommended as an important mediator that is involved in the epithelial-to-mesenchymal transition (EMT) process. However, the mechanisms underlying the chemokine (C-C motif) ligand 20 (CCL20)/chemokine (C-C motif) receptor 6 (CCR6)-AEG-1 pathway-mediated EMT in cervical cancer (CC) have not been well featured till now. We used immunohistochemistry and immunoblotting to assess the expression of AEG-1 in 94 cervical cancer tissues and cells. Subsequently, cervical cancer SiHa cells were treated with si-AEG-1 and then subjected to in vitro assays. We observed that AEG-1 proteins were highly expressed in cervical cancer tissues and closely correlated with International Federation of Gynecology and Obstetrics (FIGO) stage and metastasis. Importantly, we validated the expression of AEG-1, p-Erk1/2, p-Akt, vimentin, N-cadherin, and matrix metalloproteinase 2 (MMP2) increased in SiHa with CCL20 treatment in a concentration-dependent manner. When cells were treated with si-AEG-1, the expression of p-Erk1/2, p-Akt, vimentin, N-cadherin, and MMP2 was also downregulated. Using the cell cycle assay, the knockdown of AEG-1 inhibited the entry of G1 into S phase. In conclusion, AEG-1 mediates CCL20/CCR6-induced EMT development via both Erk1/2 and Akt signaling pathway in cervical cancer, which indicates that CCL20/CCR6-AEG-1-EMT pathway could be suggested as a useful target to affect the progression of cervical cancer.

Immune Targeting of Tumor Epithelial-Mesenchymal Transition via Brachyury-Based Vaccines

As a manifestation of their inherent plasticity, carcinoma cells undergo profound phenotypic changes during progression toward metastasis. One such phenotypic modulation is the epithelial-mesenchymal transition (EMT), an embryonically relevant process that can be reinstated by tumor cells, resulting in the acquisition of metastatic propensity, stem-like cell properties, and resistance to a variety of anticancer therapies, including chemotherapy, radiation, and some small-molecule targeted therapies. Targeting of the EMT is emerging as a novel intervention against tumor progression. This review focuses on the potential use of cancer vaccine strategies targeting tumor cells that exhibit mesenchymal-like features, with an emphasis on the current status of development of vaccine platforms directed against the T-box transcription factor brachyury, a novel cancer target involved in tumor EMT, stemness, and resistance to therapies. Also presented is a summary of potential mechanisms of resistance to immune-mediated attack driven by EMT and the development of novel combinatorial strategies based on the use of agents that alleviate tumor EMT for an optimized targeting of plastic tumor cells that are responsible for tumor recurrence and the establishment of therapeutic refractoriness.

Over-Expressed Twist Associates with Markers of Epithelial Mesenchymal Transition and Predicts Poor Prognosis in Breast Cancers via ERK and Akt Activation

Overexpression of Twist, a highly conserved basic helix-loop-helix transcription factor, is associated with epithelial-mesenchymal transition (EMT) and predicts poor prognosis in various kinds of cancers, including breast cancer. In order to further clarify Twist's role in breast cancer, we detected Twist expression in breast cancer tissues by immunohistochemistry. Twist expression was observed in 54% (220/408) of breast cancer patients and was positively associated with tumor size, Ki67, VEGF-C and HER2 expression. Conversely, Twist was negatively associated with estrogen receptor (ER), progesterone receptor (PgR) and E-cadherin expression. Patients with Twist expression had a poorer prognosis for 30-month disease free survival (DFS) (82.9%) than patients with negative Twist (92.3%). Overexpression of Twist led to dramatic changes in cellular morphology, proliferation, migratory/invasive capability, and expression of EMT-related biomarkers in breast cancer cells. Moreover, we show that Twist serves as a driver of tumorigenesis, as well as an inducer of EMT, at least in part, through activation of the Akt and extracellular signal-regulated protein kinase (ERK) pathways which are critical for Twist-mediated EMT. Our results demonstrate that Twist expression is an important prognostic factor in breast cancer patients.

Prognostic role of Twist or Snail in various carcinomas: a systematic review and meta-analysis

BACKGROUND

Twist and Snail are considered as key transcriptional repressors of E-cadherin tightly related to epithelial-to-mesenchymal transition (EMT) and cancer progression. Numerous studies have investigated the prognostic value of Twist and Snail. However, the published results were controversial or even opposite. Our article aimed to evaluate the prognostic role of Twist and Snail in patients with cancer.

DESIGN

A comprehensive literature search of PubMed, Embase and Web of Science was conducted. Pooled hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) were assessed to quantify the prognostic role.

RESULTS

The pooled HR with 38 studies for Twist was 2·18 (95% CI: 1·77-2·68, I(2) = 69·8%, P = 0·000) and for Snail with 40 studies was 1·58 (95% CI: 1·33-1·87, I(2) = 70·0%, P = 0·000), suggesting high Twist/Snail expression predicted poor prognosis related to all clinical outcomes. For Twist, the pooled HR for overall survival (OS) was 2·07 (95% CI: 1·63-2·63, I(2) = 72·6%, P = 0·000) and for progression-free/recurrence-free/metastasis-free/disease-free/cancer-free survival (PFS/RFS/MFS/DFS/CFS) was 2·36 (95% CI: 1·76-3·17, I(2) = 65·0%, P = 0·000). For Snail, the pooled HR for OS was 1·63 (95% CI: 1·33-1·99, I(2) = 70·8%, P = 0·000) and for PFS/RFS/MFS/DFS/CFS was 1·54 (95% CI: 1·17-2·02, I(2) = 59·1%, P = 0·001). All of those results were suggesting that high Twist/Snail expression was associated with poor prognosis. Furthermore, when grouped into different types of cancers, the pooled HRs were also calculated for the subgroups. No publication bias was found except studies evaluating all clinical outcomes of Twist (P = 0·006 for Begg's test and 0·006 for Egger's test).

CONCLUSIONS

Elevated Twist or Snail expression in tumour tissue indicated poor prognosis for cancer.

TBLR1 is a novel prognostic marker and promotes epithelial-mesenchymal transition in cervical cancer

BACKGROUND

Invasion and metastasis remain a critical issue in cervical cancer. However, the underlying mechanism of it in cervical cancer remains unclear. The newly discovered protein, TBLR1, plays a crucial role in regulating various key cellular functions.

METHODS

In this study, western blot, real-time RT-PCR, immunohistochemical staining, 3D morphogenesis Matrigel culture, wound healing and Boyden chamber invasion assays, xenografted tumour model, luciferase assays, and chromatin immunoprecipitation assays were used.

RESULTS

The expression of TBLR1 in cervical cancer cell lines and tissues was significantly upregulated at both the RNA and protein levels compared with that in normal cervical cells. Statistical analysis suggested that TBLR1 as an independent prognostic factor was significantly correlated with the clinical stage, survival time and recurrence. Moreover, overexpression of TBLR1 in Hela and Siha cell lines promoted invasion in vitro and in vivo with the increases of the mesenchymal factors vimentin and fibronectin and decreases of the epithelial marker α-catenin. In contrast, RNAi-mediated knockdown of TBLR1 inhibited epithelial-mesenchymal transition in vitro and in vivo. Further study indicated that this might be mediated via the NF-κB and Wnt/β-Catenin signalling pathway, and involve regulation of Snail and Twist.

CONCLUSIONS

The TBLR1 protein may be a prognostic marker in cervical cancer and play an important role in the invasion and metastasis of human cervical cancer.

Clinical significance of epithelial-mesenchymal transition-associated markers in malignant pleural mesothelioma

Epithelioid tumors with aggressive behavior have been reported; however, the epithelioid type of malignant pleural mesothelioma (MPM) has a less aggressive behavior. Few studies have evaluated the prognostic value of epithelial-mesenchymal transition (EMT) markers in MPM. We hypothesized that mesenchymal characteristics might predominate in the tumors. Tumor specimens were collected from 33 consecutive patients. We analyzed the EMT expression levels in tumor samples by an immunohistochemical analysis. Positive expression of E-cadherin, γ-catenin, vimentin, fibronectin, Twist and YB-1 was observed in 25, 14, 21, 1, 19 and 18 patients, respectively. No significant association between these markers and the clinicopathological characteristics was found. γ-Catenin demonstrated a trend towards decreased expression in sarcomatoid tumors compared to epithelioid tumors. On the other hand, a trend was noted towards higher expression of vimentin, Twist and YB-1 in sarcomatoid tumors. The survival curves demonstrated that the patients with negative γ-catenin and positive Twist staining had a tendency to have a worse prognosis. Although the individual proteins might not significantly affect the progression of MPM, the combination of γ-catenin and Twist staining can predict the prognosis of patients with MPM.

B7-H4 overexpression correlates with a poor prognosis for cervical cancer patients

Cervical cancer is a major global public health care concern and the second most commonly diagnosed malignancy among females worldwide. B7-H4 is an immunoregulatory protein that has been shown to be overexpressed in several types of cancer and is often associated with more advanced disease and poor prognosis. We investigated whether B7-H4 is a prognostic maker for cervical cancer by detecting its expression in cervical cancer specimens. Formalin-fixed, paraffin-embedded tissue blocks from cervical cancer were evaluated for B7-H4 expression by immunohistochemistry with free R software analysis. The intensity of B7-H4 immunoexpression was evaluated according to age, histological type, International Federation of Gynecology and Obstetrics (FIGO) stage, lymphovascular space invasion (LVSI) and lymph node status. We investigated the distribution and expression of B7-H4 in 102 cervical cancer specimens and determined the association between its expression and clinicopathological characteristics, including patient outcomes. Of the 102 specimens, 31 were found to be negative for B7-H4 immunoexpression, whereas 71 were B7-H4-positive. When classified by negative vs. positive expression, B7-H4 was not found to be associated with any of the clinicopathological parameters investigated. A positive B7-H4 expression significantly predicted poor overall survival (OS) when compared to negative expression (P<0.05). In the multivariate analysis, positive B7-H4 expression was identified as an independent prognostic factor for OS (P<0.05). Our data suggested that positive B7-H4 expression may be a useful biomarker in patients with cervical cancer likely to have an unfavorable clinical outcome.

Combination therapy with a second-generation androgen receptor antagonist and a metastasis vaccine improves survival in a spontaneous prostate cancer model

PURPOSE

Enzalutamide, a second-generation androgen antagonist, was approved by the U.S. Food and Drug Administration (FDA) for castration-resistant prostate cancer (CRPC) treatment. Immunotherapy has been shown to be a promising strategy for prostate cancer. This study was performed to provide data to support the combination of enzalutamide and immunotherapy for CRPC treatment.

EXPERIMENTAL DESIGN

Male C57BL/6 or TRAMP (transgenic adenocarcinoma of the mouse prostate) prostate cancer model mice were exposed to enzalutamide and/or a therapeutic vaccine targeting Twist, an antigen involved in epithelial-to-mesenchymal transition and metastasis. The physiologic and immunologic effects of enzalutamide were characterized. The generation of Twist-specific immunity by Twist-vaccine was assessed. Finally, the combination of enzalutamide and Twist-vaccine to improve TRAMP mice overall survival was evaluated.

RESULTS

Enzalutamide mediated immunogenic modulation in TRAMP-C2 cells. In vivo, enzalutamide mediated reduced genitourinary tissue weight, enlargement of the thymus, and increased levels of T-cell excision circles. Because no changes were seen in T-cell function, as determined by CD4(+) T-cell proliferation and regulatory T cell (Treg) functional assays, enzalutamide was determined to be immune inert. Enzalutamide did not diminish the ability of Twist-vaccine to generate Twist-specific immunity. Twist was confirmed as a valid tumor antigen in TRAMP mice by immunohistochemistry. The combination of enzalutamide and Twist-vaccine resulted in significantly increased overall survival of TRAMP mice compared with other treatment groups (27.5 vs. 10.3 weeks). Notably, the effectiveness of the combination therapy increased with disease stage, i.e., the greatest survival benefit was seen in mice with advanced-stage prostate tumors.

CONCLUSIONS

These data support the combination of enzalutamide and immunotherapy as a promising treatment strategy for CRPC. Clin Cancer Res; 19(22); 6205-18. ©2013 AACR.

Expression of E-cadherin, Twist, and p53 and their prognostic value in patients with oral squamous cell carcinoma

PURPOSE

Epithelial-mesenchymal transition (EMT) and p53 play important roles in controlling cancer invasion and metastasis. However, discrepancies still exist in the relationship between the expression of an epithelial marker E-cadherin and predicting short survival of patients in many types of cancer. In this study, we aimed to determine the levels of E-cadherin, Twist, and p53 in tumor tissues from patients with oral squamous cell carcinoma (OSCC) and their clinical significances.

METHODS

The protein expression of 112 OSCC tumor and 16 benign tissues was examined by immunohistochemistry staining. Overall survival rates of 112 OSCC patients were measured using Kaplan-Meier estimates and the log-rank tests.

RESULTS

E-cadherin and p53 downregulation were found in 70 of 112 (62.5 %) and 66 of 112 (59.0 %), respectively, and Twist overexpression was found in 72 of 112 (64.3 %) studied cases of OSCC patients. Expression of E-cadherin was significantly associated with tumor location (P = 0.004) and mortality (P = 0.010). Patients with lower E-cadherin expression (P = 0.024), betel quid chewing (P = 0.006), smoking (P = 0.001), tumor size >2 cm (P = 0.001), advanced tumor stage (P = 0.043), and recurrence (P < 0.001) exhibited a poorer outcome. Multivariate analysis showed that E-cadherin is an independent marker for survival prediction. Additionally, low E-cadherin expression is significantly correlated with low p53 expression.

CONCLUSIONS

E-cadherin is an independent marker for survival prediction in OSCC. Co-evaluation of E-cadherin and p53 expression might be a valuable tool for predicting OSCC patient outcome.

Twist: a molecular target in cancer therapeutics

Twist, the basic helix-loop-helix transcription factor, is involved in the process of epithelial to mesenchymal transitions (EMTs), which play an essential role in cancer metastasis. Overexpression of Twist or its promoter methylation is a common scenario in metastatic carcinomas. Twist is activated by a variety of signal transduction pathways, including Akt, signal transducer and activator of transcription 3, mitogen-activated protein kinase, Ras, and Wnt signaling. Activated Twist upregulates N-cadherin and downregulates E-cadherin, which are the hallmarks of EMT. Moreover, Twist plays an important role in some physiological processes involved in metastasis, like angiogenesis, invadopodia, extravasation, and chromosomal instability. Twist also protects cancer cells from apoptotic cell death. In addition, Twist is responsible for the stemness of cancer cells and the generation of drug resistance. Recently, targeting Twist has gained significant interests in cancer therapeutics. The inactivation of Twist by small RNA technology or chemotherapeutic approach has been proved successful. Moreover, several inhibitors which are antagonistic to the upstream or downstream molecules of Twist signaling pathways have also been identified. Development of potential treatment strategies by targeting Twist has a great promise in cancer therapeutics.

TWIST1 promoter methylation is associated with prognosis in tonsillar squamous cell carcinoma

Tonsillar squamous cell carcinomas (TSCC) frequently present with locally advanced diseases and cervical metastases, which are associated with poor prognoses. Epithelial-mesenchymal transition (EMT) is critical for tumor invasiveness and metastatic potential. Recent studies have shown that TWIST1-inducing EMT is overexpressed and hypermethylated in several cancers, indicating disease progression. The aim of the present study was to determine the clinical and prognostic significance of TWIST1 hypermethylation and EMT-related protein expression in TSCC. Methylation levels of TWIST1 promoter were analyzed by quantitative real-time methylation-specific polymerase chain reaction. Immunohistochemical analyses of TWIST1, Snail, and SMAD nuclear interacting protein-1 (SNIP1) were performed in 65 formalin-fixed, paraffin-embedded blocks of surgically resected specimens. TWIST1 promoter hypermethylation was found in 27.7% (18/65) of TSCCs. TWIST1 promoter hypermethylation was associated with poor differentiation (P = .012). Contralateral cervical lymph node metastasis was more frequently observed in TWIST1-methylated tumors (P = .029). High protein expressions of TWIST1, Snail, and SNIP1 were observed in 14 TSCC specimens (21.5%), 21 TSCC specimens (32.3%), and 38 TSCC specimens (58.5%), respectively. SNIP1 expression correlated significantly with TWIST1 methylation (P = .001), whereas TWIST1 protein expression did not. Contralateral cervical lymph node metastasis was an independent risk factor of the decreased overall survival rate (P = .002). TWIST1 methylation (P = .031) and pN stage (P = .037) were independent factors of poor prognoses affecting disease-free survival. TWIST1 promoter hypermethylation may be a useful molecular marker for predicting prognoses and contralateral cervical lymph node metastases in patients with TSCC.

Aberrant expression of hypoxia-inducible factor 1α, TWIST and E-cadherin is associated with aggressive tumor phenotypes in endometrioid endometrial carcinoma

OBJECTIVE

Intratumoral hypoxia promotes angiogenesis, invasion and epithelial-mesenchymal transition, a pivotal event in tumor metastasis. TWIST is a master regulator of multiple developmental processes and has recently been shown to be the key factor responsible for cancer metastasis via the inhibition of E-cadherin expression, a hallmark of epithelial-mesenchymal transition. This study aimed to determine the expression of hypoxia-inducible factor 1α, TWIST and E-cadherin in patients with endometrioid endometrial carcinoma and to examine their clinical significance in endometrioid endometrial carcinoma progression.

METHODS

Using immunohistochemical and tissue microarray approaches, we evaluated the expression of hypoxia-inducible factor 1α, TWIST and E-cadherin in normal endometrial (n = 35), atypical hyperplasia (n = 28) and endometrioid endometrial carcinoma samples (n = 124). Furthermore, we statistically analyzed the association between these markers, as well as their correlation with clinicopathologic variables.

RESULTS

The expression of hypoxia-inducible factor 1α and TWIST were markedly increased, whereas E-cadherin was decreased, as lesions progressed from normal endometrium to atypical hyperplasia to carcinoma (P < 0.01). Among various clinical parameters, the expression of hypoxia-inducible factor 1α and TWIST was strikingly elevated with aggressive tumor characteristics, including higher pathologic grade, deep myometrial invasion and lymph node involvement (P < 0.05). More importantly, overexpression of hypoxia-inducible factor 1α positively correlated with enhanced TWIST expression in endometrioid endometrial carcinoma samples (r = 0.249, P < 0.01); however, statistical analysis showed a negative relationship between TWIST upregulation and E-cadherin downregulation (r = -0.183, P = 0.042).

CONCLUSIONS

These results demonstrated for the first time that the hypoxia-inducible factor 1α/TWIST/E-cadherin pathway may play a critical role in invasion and metastasis of endometrioid endometrial carcinoma. The combined evaluation of these markers may be useful in predicting aggressive phenotypes and thus prognosis in patients with endometrioid endometrial carcinoma.

Linkage between Twist1 and Bmi1: molecular mechanism of cancer metastasis/stemness and clinical implications

Cancer metastasis is the major cause of cancer-related death despite significant improvements in multimodal cancer therapy. Epithelial-mesenchymal transition (EMT), a major mechanism of cancer metastasis, is a process that generates cells with stem cell-like properties (cancer stemness). Cancer stemness is a concept that describes a minor population of cells (cancer stem cells) residing within a tumour that are able to self-renew and are resistant to conventional therapy. The mechanisms delineating the generation of cancer stemness and its connection to cancer metastasis remain largely unknown. Twist1 is an EMT regulator and increased Twist1 expression, which has prognostic significance in various human cancers, has been widely reported. Bmi1 is a critical component of polycomb repressive complex (PRC) 1, which maintains self-renewal and stemness. Bmi1 is frequently overexpressed in different types of human cancers and can induce drug resistance (Table 2). Recent studies have shown that Twist1 directly activates Bmi1 expression and that these two molecules function together to mediate cancer stemness and EMT. These results present a unique mechanism of EMT-induced cancer metastasis and stemness. Further investigation of the mechanisms of EMT-mediated cancer metastasis and stemness will contribute to the management and treatment of metastatic cancers.

Targeting SPARC by lentivirus-mediated RNA interference inhibits cervical cancer cell growth and metastasis

Background

Secreted protein acidic and rich in cysteine (SPARC), a calcium-binding matricellular glycoprotein, is implicated in the progressions of some cancers. However, no information has been available to date regarding the function of SPARC in cervical cancer cell growth and metastasis.

Methods

In this study, we isolated and established high invasive subclones and low invasive subclones from human cervical cancer cell lines HeLa and SiHa by the limited dilution method. Real-time q-RT-PCR, Western Blot and ICC were performed to investigate SPARC mRNA and protein expressions in high invasive subclones and low invasive subclones. Then lentivirus vector with SPARC shRNA was constructed and infected the highly invasive subclones. Real-time q-RT-PCR, Western Blot and ICC were also performed to investigate the changes of SPARC expression after viral infection. In functional assays, effects of SPARC knockdown on the biological behaviors of cervical cancer cells were investigated. The mechanisms of SPARC in cervical cancer proliferation, apoptosis and invasion were also researched.

Results

SPARC was over-expressed in the highly invasive subclones compared with the low invasive subclones. Knockdown of SPARC significantly suppressed cervical cancer cell proliferation, and induced cell cycle arrest at the G1/G0 phase through the p53/p21 pathway, also caused cell apoptosis accompanied by the decreased ratio of Bcl-2/Bax, and inhibited cell invasion and metastasis accompanied by down-regulated MMP2 and MMP9 expressions and up-regulated E-cadherin expression.

Conclusion

SPARC is related to the invasive phenotype of cervical cancer cells. Knockdown of SPARC significantly suppresses cervical cancer cell proliferation, induces cell apoptosis and inhibits cell invasion and metastasis. SPARC as a promoter improves cervical cancer cell growth and metastasis.

Expression of Twist enhances risk of poor oncologic outcome in patients with stage Ib to II cervical carcinoma with lymphovascular space involvement

Twist, a basic helix-loop-helix transcription factor, promotes cancer cell epithelial-mesenchymal transition and metastasis. Here, we aimed to examine the association between Twist expression and lymphovascular space involvement for early-stage cervical carcinoma. Paraffin sections from 90 patients with stage Ib to IIb cervical carcinoma were immunostained with Twist antibody, and the staining intensities were semiquantitatively evaluated. Of the 90 cervical carcinoma specimens examined in this study, 51 (56.7%) were negative for Twist and 39 (43.3%) were positive for Twist immunoreactivity. The 5-year overall survival rates of patients in the Twist-negative and Twist-positive groups were 98.0% and 75.8%, respectively. Univariate and multivariate analyses demonstrated that Twist expression was an independent prognostic factor for overall survival and recurrence-free survival (univariate: P = .0069 [overall survival], P = .0092 [recurrence-free survival]: multivariate: P = .0118 [overall survival], P = .0118 [recurrence-free survival]). On stratifying based on the negative lymphovascular space involvement status, the overall survival and recurrence-free survival of patients in the Twist-negative group was the same as that of those in the Twist-positive group (log-rank: P = .262 [recurrence-free survival], P = .899 [overall survival]). In contrast, with lymphovascular space involvement, a significantly poorer recurrence-free survival was predicted for patients in the Twist-positive group compared with that in the Twist-negative group (P = .0021). Twelve (75.0%) of 16 patients showing recurrence belonged to the Twist-positive group, and 83.3% (10/12) of them experienced recurrence in distant organs or the peritoneal cavity. This study suggested that the assessment of the Twist immunoreactivity and lymphovascular space involvement may distinguish high- from low-risk patients with locally invasive cervical carcinoma.

Cancer vaccines targeting the epithelial-mesenchymal transition: tissue distribution of brachyury and other drivers of the mesenchymal-like phenotype of carcinomas

The epithelial-mesenchymal transition (EMT) is thought to be a critical step along the metastasis of carcinomas. In addition to gaining motility and invasiveness, tumor cells that undergo EMT also acquire increased resistance to many traditional cancer treatment modalities, including chemotherapy and radiation. As such, EMT has become an attractive, potentially targetable process for therapeutic interventions against tumor metastasis. The process of EMT is driven by a group of transcription factors designated as EMT transcription factors, such as Snail, Slug, Twist, and the recently identified T-box family member, Brachyury. In an attempt to determine which of these drivers of EMT is more amenable to targeted therapies and, in particular, T-cell-mediated immunotherapeutic approaches, we have examined their relative expression levels in a range of human and murine normal tissues, cancer cell lines, and human tumor biopsies. Our results demonstrated that Brachyury is a molecule with a highly restricted human tumor expression pattern. We also demonstrated that Brachyury is immunogenic and that Brachyury-specific CD8(+) T cells expanded in vitro are able to lyse Brachyury-positive tumor cells. We thus propose Brachyury as an attractive target for vaccination strategies designed to specifically target tumor cells undergoing EMT.

Short hairpin RNA targeting Twist1 suppresses cell proliferation and improves chemosensitivity to cisplatin in HeLa human cervical cancer cells

Development of multidrug resistance (MDR) remains a major hurdle to successful cancer chemotherapy and MDR1/P-gp overexpression is believed to be mainly responsible for MDR of tumor cells. Twist1, which is a highly conserved transcription factor that belongs to the family of basic helix-loop-helix proteins, has been shown to be a major regulator of the epithelial-mesenchymal transition (EMT), and therefore promotes carcinoma metastasis. Recently, a novel function of Twist1 was reported to confer radioresistance or chemoresistance in cervical cancer. However, mechanisms of such efficacy are not completely elucidated. In the present study, we firstly analyzed the relationship between Twist1 and MDR1/P-gp expression in human cervical cancer specimens and demonstrated a positive correlation between Twist1 and MDR1/P-gp expression in the same patient. Additionally, we provide the first evidence that silencing of Twist1 by RNAi downregulated MDR1/P-gp expression in HeLa cervical cancer cells, suppressed the cell proliferation, inhibited Rhodamine123 efflux activity of cells and sensitized cells to cisplatin treatment. Collectively, these findings suggest that Twist1-mediated modulation of MDR1/P-gp expression plays an important role in sensitization of cervical cancer cells to cisplatin, and also indicate a novel therapeutic strategy to overcome drug resistance through inactivation of Twist1 expression in cervical cancer.

TWIST and p-Akt immunoexpression in normal oral epithelium, oral dysplasia and in oral squamous cell carcinoma

Objectives: The aim of this study was to evaluate the immunoexpression of TWIST and p-Akt proteins in oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC), correlating their expressions with the histological features of the lesions. Study design: Immunohistochemical studies were carried out on 10 normal oral epithelium, 30 OL and 20 OSCC formalin-fixed, paraffin-embedded tissue samples. Immunoperoxidase reactions for TWIST and p-Akt proteins were applied on the specimens and the positivity of the reactions was calculated for 1000 epithelial cells. Results: Kruskal-Wallis and Dunn’s post tests revealed a significant difference in TWIST and p-Akt immunoexpression among normal oral mucosa, OL and OSCC. In addition, a significant positive correlation was found between TWIST and p-Akt expressions according to the Pearson’s correlation test. Conclusions: The results obtained in the current study suggest that TWIST and p-Akt may participate of the multi-step process of oral carcinogenesis since its early stages.

Key words: Oral cancer, oral leukoplakia, dysplasia, immunohistochemistry.

Molecules involved in epithelial-mesenchymal transition and epithelial-stromal interaction in phyllodes tumors: implications for histologic grade and prognosis

The aim of this study was to investigate the expression of molecules associated with epithelial-mesenchymal transition (EMT) and epithelial-stromal interactions (ESI) and to evaluate their roles in phyllodes tumors (PTs). Tissue microarrays (TMAs) were constructed from 207 PT specimens (157 benign, 34 borderline and 16 malignant). The presence of EMT-related markers including N-cadherin, Twist, TGF-beta, HMGA2, S100A4 and Ezrin as well as ESI-related molecules such as SDF1 and CXCR4 among the TMAs was assessed immunohistochemically. Immunohistochemical results were analyzed in terms of clinicopathologic parameters. For higher grade PTs, expressions of Twist (p < 0.001), HMGA2 (p = 0.005), S100A4 (p < 0.001), CXCR4 (p < 0.001) and TGF-beta (p < 0.001) were higher. As PTs showed higher stromal cellularity, higher stromal mitosis, stromal overgrowth and infiltrative tumor margin, the expressions of Twist, HMGA2 and CXCR4 in the stromal component thereof were increased (p < 0.05). High Twist expression in the stromal component was associated with shorter disease-free survival (DFS) and overall survival (OS) (p < 0.001) as well as shorter OS in multivariate COX analysis (p = 0.031, odds ratio: 24.6). In conclusion, the expressions of Twist, HMGA2, TGF-beta and S100A4, which are EMT-associated molecules, and CXCR4, an ESI-associated molecule, were increased in the stromal component of advanced grade PTs. Further, high expression of Twist in the stromal component was correlated with poorer prognoses.

ARTEMIN synergizes with TWIST1 to promote metastasis and poor survival outcome in patients with ER negative mammary carcinoma

Introduction

ARTEMIN (ARTN) is an estrogen regulated growth factor, the expression of which promotes resistance to antiestrogen therapies and predicts poorer survival outcome of patients with estrogen receptor (ER) positive mammary carcinoma (ER+MC) treated with tamoxifen. ARTN is also expressed in ER negative mammary carcinoma (ER-MC). Herein, we determined the role of ARTN in ER-MC and defined the mechanism of action producing poor patient prognosis.

Methods

We modulated the expression of ARTN in two ER- (mesenchymal/claudin-low) mammary carcinoma cell lines (BT549 and MDA-MB-231) by forced expression or small interfering RNA (siRNA) mediated depletion. The effects of modulation of ARTN expression were examined by various in vitro measures of oncogenicity, including the expression of TWIST1 messenger RNA (mRNA) and protein. In vitro results were correlated to xenograft studies in immunodeficient mice. Co-expression of ARTN and TWIST1 and their association to poor survival outcome were examined in a cohort of patients with ER-MC. Pathway analysis was performed by pharmacological inhibition of phosphorylation of AKT (pAKT-Ser 473) or modulation of TWIST1 expression.

Results

ARTN expression resulted in ER-MC cells with enhanced mesenchymal characteristics, including increased invasion and a gene expression profile consistent with enhanced mesenchymal phenotype. ARTN stimulated ER-MC cell anchorage independent and 3D matrigel growth, endothelial cell adhesion and transmigration of ER-MC cells through an endothelial cell barrier. Forced expression of ARTN produced a larger, locally invasive tumour mass with tumour emboli that produced distant metastasis. ARTN regulated TWIST1 expression in ER-MC cells and ARTN expression was significantly correlated to TWIST1 expression in a panel of mammary carcinoma cell lines and in a cohort of patients with ER-MC. Low expression of both ARTN and TWIST1 predicted 100% relapse free and overall survival in patients with ER-MC, whereas high expression of both ARTN and TWIST1 was associated with a poor survival outcome. ARTN stimulated an increase in TWIST1 expression via increased AKT activity. siRNA mediated depletion of TWIST1 abrogated ARTN stimulated cellular behaviour associated with metastasis, and forced expression of TWIST1 abrogated the functional effects of ARTN depletion.

Conclusions

ARTN and TWIST1 synergize to produce a worse outcome in ER-MC and combined inhibition of ARTN and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) may therefore provide a novel therapeutic strategy in this subtype of mammary carcinoma.

Correlation of TWIST2 up-regulation and epithelial-mesenchymal transition during tumorigenesis and progression of cervical carcinoma

OBJECTIVE

Globally, cervical cancer is the second most common cancer among women, and determining potential targets involved in tumor progression is necessary. This study investigated the clinic-pathological significance of twist homolog 2 (TWIST2), a basic helix-loop-helix transcription factor, and correlated TWIST2 and E-cadherin expression in cervical cancer.

METHODS

A series of 142 samples, including 14 cases of normal cervical tissues, 58 cases of cervical intraepithelial neoplasia (CIN) and 70 cases of squamous cell carcinoma (SCC), were examined TWIST2 and E-cadherin immunohistochemical staining and statistical analysis.

RESULTS

Increased cytoplasmic and nuclear expression levels of TWIST2 were associated with the malignant transformation of cervical epithelium and the histological progression of cervical cancer. A logistic test showed that TWIST2 was a relatively independent predictor of lymph node metastasis of SCC. Further, increased levels of TWIST2 were also associated with aberrant expression of E-cadherin, an important EMT indicator.

CONCLUSIONS

The present data suggest that TWIST2 overexpression was significantly linked to cervical cancer progression, which makes it a promising marker for determining the metastatic potential of cervical cancer, and up-regulation of TWIST2, in combination with aberrant E-cadherin expression in primary cervical cancer tissues, may predict the malignant transformation and distal metastasis of carcinomas.

Twist and snai1 expression in pharyngeal squamous cell carcinoma stroma is related to cancer progression

Background

Epithelial-mesenchymal transition (EMT) is a crucial process in tumorigenesis since tumor cells attain fibroblast-like features enabling them to invade to surrounding tissue. Two transcription factors, TWIST and SNAI1, are fundamental in regulating EMT.

Methods

Immunohistochemistry was used to study the expression of TWIST and SNAI1 in 109 pharyngeal squamous cell carcinomas.

Results

Tumors with intense stromal staining of TWIST relapsed more frequently (p = 0.04). Tumors with both positive TWIST and SNAI1 immunoreactivity in the stroma were at least Stage II (p = 0.05) and located more often in hypopharynx (p = 0.035). Tumors with negative immunostaining of TWIST and SNAI1 in the stromal compartment were smaller (T1-2) (p = 0.008), less advanced (SI-II) (p = 0.031) and located more often in the oropharynx (p = 0.007). Patients with negative SNAI1 and TWIST immunostaining in tumor stroma had a better 5-year disease-specific and overall survival (p = 0.037 and p = 0.014 respectively).

Conclusion

TWIST and SNAI1 expression in stromal cells is associated with clinical and histopathological characteristics that indicate progressive disease. Negative expression of these EMT-promoting transcription factors predicts a better outcome.