Twist1 induces distinct cell states depending on TGFBR1-activation

Phenotypic and transcriptional changes in lens epithelial cells following acute and fractionated ionizing radiation exposure

PURPOSE

Exposure to ionizing radiation is one of the known risk factors for the development of lens opacities. It is believed that radiation interactions with lens epithelial cells (LEC) are the underlying cause of cataract development, however, the exact mechanisms have yet to be identified. The aim of this study was to investigate how different radiation dose and fractionation impact normal LEC function.

MATERIALS AND METHODS

A human derived LEC cell line (HLE-B3) was exposed to a single acute x-ray dose (0.25 Gy) and 6 fractionated doses (total dose of 0.05, 0.1, 0.25, 0.5, 1, and 2 Gy divided over 5 equal fractions). LEC were examined for proliferation using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and migration using a Boyden chamber assay at various time points (0.25, 0.5, 1, 2, 4, 7, 9, 11, and 14 d) post-irradiation. Transcriptomic analysis through RNA sequencing was also performed to identify differentially expressed genes and regulatory networks in cells following 4 different acute exposures and 1 fractionated exposure.

RESULTS

Exposure to an acute dose of 0.25 Gy significantly increased proliferation and migration rates, peaking at 7 d post irradiation (20% and 240% greater than controls, respectively), before returning to baseline levels by day 14. Fractionated exposures had minimal effects up to a dose of 0.5 Gy, but significantly reduced proliferation and migration after 1 and 2 Gy by up to 50%. The largest transcriptional response occurred 12 h after an acute 0.25 Gy dose, with 362 genes up-regulated and 288 genes down-regulated. A unique panel of differentially expressed genes was observed between moderate versus high dose exposures, suggesting a dose-dependent transcriptional response in LEC that is more pronounced at lower doses. Gene ontology and upstream regulator analysis identified multiple biological processes and molecular functions implicated in the radiation response, in particular differentiation, motility, receptor/ligand binding, cell signaling and epithelial-mesenchymal cell transition.

CONCLUSIONS

Overall, this research provides novel insights into the dose and fractionation effects on functional changes and transcriptional regulatory networks in LEC, furthering our understanding of the mechanisms behind radiation induced cataracts.

Resistance to mesenchymal reprogramming sustains clonal propagation in metastatic breast cancer

The acquisition of mesenchymal traits is considered a hallmark of breast cancer progression. However, the functional relevance of epithelial-to-mesenchymal transition (EMT) remains controversial and context dependent. Here, we isolate epithelial and mesenchymal populations from human breast cancer metastatic biopsies and assess their functional potential in vivo. Strikingly, progressively decreasing epithelial cell adhesion molecule (EPCAM) levels correlate with declining disease propagation. Mechanistically, we find that persistent EPCAM expression marks epithelial clones that resist EMT induction and propagate competitively. In contrast, loss of EPCAM defines clones arrested in a mesenchymal state, with concomitant suppression of tumorigenicity and metastatic potential. This dichotomy results from distinct clonal trajectories impacting global epigenetic programs that are determined by the interplay between human ZEB1 and its target GRHL2. Collectively, our results indicate that susceptibility to irreversible EMT restrains clonal propagation, whereas resistance to mesenchymal reprogramming sustains disease spread in multiple models of human metastatic breast cancer, including patient-derived cells in vivo.

The activation of EP300 by F11R leads to EMT and acts as a prognostic factor in triple-negative breast cancers

Cancer progression is influenced by junctional adhesion molecule (JAM) family members. The relationship between JAM family members and different types of cancer was examined using The Cancer Genome Atlas dataset. mRNA levels of the F11R (F11 receptor) in tumours were inversely correlated to the expression of JAM-2 and JAM-3. This relationship was unique to breast cancer (BCa) and was associated with poor prognosis (p = 0.024, hazard ratio = 1.44 [1.05-1.99]). A 50-gene molecular signature (prediction analysis of microarray 50) was used to subtype BCa. F11R mRNA expression significantly increased in human epidermal growth factor receptor 2 (HER2)-enriched (p = 0.0035) and basal-like BCa tumours (p = 0.0005). We evaluated F11R protein levels in two different compositions of BCa subtype patient tissue array cohorts to determine the relationship between BCa subtype and prognosis. Immunohistochemistry staining revealed that a high F11R protein level was associated with poor overall survival (p < 0.001; Taipei Medical University [TMU] cohort, p < 0.001; Kaohsiung Veterans General Hospital [KVGH] cohort) or disease-free survival (p < 0.001 [TMU cohort], p = 0.034 [KVGH cohort]) in patients with BCa. Comparison of F11R levels in different subtypes revealed the association of poor prognosis with high levels of F11R among luminal (p < 0.001 [TMU cohort], p = 0.027 [KVGH cohort]), HER2 positive (p = 0.018 [TMU cohort], p = 0.037 [KVGH cohort]), and triple-negative (p = 0.013 [TMU cohort], p = 0.037 [KVGH cohort]) BCa. F11R-based RNA microarray analysis and Ingenuity Pathway Analysis were successful in profiling the detailed gene ontology of triple-negative BCa cells regulated by F11R. The EP300 transcription factor was highly correlated with F11R in BCa (R = 0.51, p < 0.001). By analysing these F11R-affected molecules with the L1000CDs datasets, we were able to predict some repurposing drugs for potential application in F11R-positive BCa treatment.

Expressions of TWIST1 and CD105 markers in colorectal cancer patients and their association with metastatic potential and prognosis

Background

TWIST1 and CD105, which contribute to tumor malignancy, are overexpressed in cancers. Accordingly, TWIST1 enhances epithelial-to-mesenchymal transition (EMT) and promotes the formation of cancer stem cells (CSCs). Also, CD105 is a neoangiogenesis marker in endothelial cells, which is introduced as a CSC marker in tumoral epithelial cells in several types of cancers. The present study was aimed to investigate expressions of TWIST1 and CD105 in colorectal cancer (CRC) patients.

Methods

Expressions of TWIST1 and CD105 in 250 CRC tissue samples were evaluated using immunohistochemistry on tissue microarrays (TMAs). In this regard, TWIST1 expression was investigated in the subcellular locations (cytoplasm and nucleus), while CD105 was mapped in endothelial cells and cytoplasmic tumor cells of CRC tissues. The association between the expression of these markers and clinicopathological parameters, as well as survival outcomes were analyzed.

Results

Results indicate a statistically significant association between higher nuclear expression levels of TWIST1 and distant metastases in CRC (P = 0.040) patients. In addition, it was shown that the increased nuclear expression of TWIST1 had a poor prognostic value for disease-specific survival (DSS) and progression-free survival (PFS) (P = 0.042, P = 0.043, respectively) in patients with CRC. Moreover, analysis of CD105 expression level has revealed that there is a statistically significant association between the increased expression of CD105 in tumoral epithelial cells and more advanced TNM stage (P = 0.050).

Conclusions

Our results demonstrate that nuclear TWIST1 and cytoplasmic CD105 expressions in tumor cells had associations with more aggressive tumor behavior and more advanced diseases in CRC cases.

Plasticity of cancer cell invasion: Patterns and mechanisms

Cancer cell migration and invasion are integral components of metastatic disease, which is the major cause of death in cancer patients. Cancer cells can disseminate and migrate via several alternative mechanisms including amoeboid cell migration, mesenchymal cell migration, and collective cell migration. These diverse movement strategies display certain specific and distinct hallmarks in cell-cell junctions, actin cytoskeleton, matrix adhesion, and protease activity. During tumor progression, cells pass through complex microenvironments and adapt their migration strategies by reversible mesenchymal-amoeboid and individual-collective transitions. This plasticity in motility patterns enables cancer cells disseminate further and thus limit the efficiency of anti-metastasis therapies. In this review, we discuss the modes and mechanisms of cancer cell migration and focus on the plasticity of tumor cell movement as well as potential emerging therapeutic options for reducing cancer cell invasion.

Systems biology approach suggests new miRNAs as phenotypic stability factors in the epithelial-mesenchymal transition

The epithelial-mesenchymal transition (EMT) is a cellular programme on which epithelial cells undergo a phenotypic transition to mesenchymal ones acquiring metastatic properties such as mobility and invasion. TGF-β signalling can promote the EMT process. However, the dynamics of the concentration response of TGF-β-induced EMT is not well explained. In this work, we propose a logical model of TGF-β dose dependence of EMT in MCF10A breast cells. The model outcomes agree with experimentally observed phenotypes for the wild-type and perturbed/mutated cases. As important findings of the model, it predicts the coexistence of more than one hybrid state and that the circuit between TWIST1 and miR-129 is involved in their stabilization. Thus, miR-129 should be considered as a phenotypic stability factor. The circuit TWIST1/miR-129 associates with ZEB1-mediated circuits involving miRNAs 200, 1199, 340, and the protein GRHL2 to stabilize the hybrid state. Additionally, we found a possible new autocrine mechanism composed of the circuit involving TGF-β, miR-200, and SNAIL1 that contributes to the stabilization of the mesenchymal state. Therefore, our work can extend our comprehension of TGF-β-induced EMT in MCF10A cells to potentially improve the strategies for breast cancer treatment.

What makes cells move: Requirements and obstacles for leader cells in collective invasion

Most recently, mounting evidence has shown that cancer cells can invade as a cohesive and multicellular group with coordinated movement, which is called collective invasion. In this cohesive cancer cell group, cancer cells at the front of collective invasion are defined as leader cell that are responsible for many aspects of collective invasion, including sensing the microenvironment, determining the invasion direction, modifying the path of invasion and transmitting information to other cells. To fulfill their dispensable roles, leader cells are required to embark on some specific phenotypes with unusual expression of some proteins and it's very important to investigate into these proteins as they may serve as potential therapeutic targets. Here, in this review we will summarize current knowledge on four emerging proteins highly expressed in leader cells including K14, ΔNp63α, Dll4 and cysteine protease cathepsin B (CTSB), with a focus on their important roles in collective invasion and special mechanisms by which they promote collective invasion.

Hybrid epithelial/mesenchymal phenotypes promote metastasis and therapy resistance across carcinomas

Cancer metastasis and therapy resistance are the major unsolved clinical challenges, and account for nearly all cancer-related deaths. Both metastasis and therapy resistance are fueled by epithelial plasticity, the reversible phenotypic transitions between epithelial and mesenchymal phenotypes, including epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET). EMT and MET have been largely considered as binary processes, where cells detach from the primary tumor as individual units with many, if not all, traits of a mesenchymal cell (EMT) and then convert back to being epithelial (MET). However, recent studies have demonstrated that cells can metastasize in ways alternative to traditional EMT paradigm; for example, they can detach as clusters, and/or occupy one or more stable hybrid epithelial/mesenchymal (E/M) phenotypes that can be the end point of a transition. Such hybrid E/M cells can integrate various epithelial and mesenchymal traits and markers, facilitating collective cell migration. Furthermore, these hybrid E/M cells may possess higher tumor-initiation and metastatic potential as compared to cells on either end of the EMT spectrum. Here, we review in silico, in vitro, in vivo and clinical evidence for the existence of one or more hybrid E/M phenotype(s) in multiple carcinomas, and discuss their implications in tumor-initiation, tumor relapse, therapy resistance, and metastasis. Together, these studies drive the emerging notion that cells in a hybrid E/M phenotype may occupy 'metastatic sweet spot' in multiple subtypes of carcinomas, and pathways linked to this (these) hybrid E/M state(s) may be relevant as prognostic biomarkers as well as a promising therapeutic targets.

ETS1 regulates Twist1 transcription in a KrasG12D/Lkb1-/- metastatic lung tumor model of non-small cell lung cancer

Distinct members of the Ets family of transcription factors act as positive or negative regulators of genes involved in cellular proliferation, development, and tumorigenesis. In human lung cancer, increased ETS1 expression is associated with poor prognosis and metastasis. We tested whether ETS1 contributes to lung tumorigenesis by binding to Twist1, a gene involved in tumor cell motility and dissemination. We used a mouse lung cancer model with metastasis driven by conditionally activated Kras and concurrent tumor suppressor Lkb1 loss (Kras^G12D/ Lkb1^-/- model) and a similar model of lung cancer that does not metastasize, driven by conditionally activated Kras alone (Kras^G12D model). We show that Ets1 and Twist1 gene expression differs between Kras^G12D tumors (low Ets1 and Twist1 expression) and Kras^G12D/Lkb1^-/- tumors (high Ets1 and Twist1 expression). In human lung tumors, ETS1 and TWIST1 expression positively correlates and low combined ETS1 and TWIST1 levels are associated with improved survival compared to high levels. Using mouse cell lines derived from Kras^G12D and Kras^G12D/Lkb1^-/- mouse models and the human lung cancer (A549) cell line, we show that ETS1 regulates Twist1 expression. Chromatin immunoprecipitation assays confirm binding of ETS1 to the Twist1 promoter. Overexpression studies show that ETS1 transactivates Twist1 promoter activity in mouse and human cells. Silencing endogenous Ets1 by siRNA in mouse cell lines decreases Twist1 mRNA levels, decreases invasion, and increases cell growth. Ets1 and Twist1 are at the crossroad of several signaling pathways in cancer. Understanding their regulation may inform the development of therapies to impair lung tumor metastasis.

miR-320 inhibited ovarian cancer oncogenicity via targeting TWIST1 expression

Ovarian cancer is the most lethal gynecological cancer in most countries. Increasing studies have demonstrated that dysregulation of microRNAs (miRNAs) can contribute to cancer progression. In this study, we showed that miR-320 was underexpressed in ovarian cancer samples compared to their non-tumor tissues. The expression of Twist homolog 1 (TWIST1) in ovarian cancer tissues was upregulated compared with that in the non-tumorous tissues. We found that the expression of TWIST1 was inversely correlated with that of miR-320 in the ovarian cancer. Overexpression of miR-320 suppressed cell proliferation, cell cycle and invasion in ovarian cancer. We identified TWIST1 as a direct target gene of miR-320 in the ovarian cancer cell. Overexpression of TWIST1 promoted the ovarian cancer cell proliferation, cell cycle and invasion. Ectopic expression of TWIST1 restored the effects of miR-320 on cell proliferation, cell cycle and invasion. These findings revealed that miR-320 was a tumor suppressive gene that supressed cell prloferation, cycle and invasion through targeting TWIST1 in ovarian cancer.