Mesenchymal Phenotype Research Articles

LncRNA LITATS1 suppresses TGF‐β‐induced EMT and cancer cell plasticity by potentiating TβRI degradation

Epithelial cells acquire mesenchymal phenotypes through epithelial‐mesenchymal transition (EMT) during cancer progression. However, how epithelial cells retain their epithelial traits and prevent malignant transformation is not well understood. Here, we report that the long noncoding RNA LITATS1 (LINC01137, ZC3H12A‐DT) is an epithelial gatekeeper in normal epithelial cells and inhibits EMT in breast and non‐small cell lung cancer cells. Transcriptome analysis identified LITATS1 as a TGF‐β target gene. LITATS1 expression is reduced in lung adenocarcinoma tissues compared with adjacent normal tissues and correlates with a favorable prognosis in breast and non‐small cell lung cancer patients. LITATS1 depletion promotes TGF‐β‐induced EMT, migration, and extravasation in cancer cells. Unbiased pathway analysis demonstrated that LITATS1 knockdown potently and selectively potentiates TGF‐β/SMAD signaling. Mechanistically, LITATS1 enhances the polyubiquitination and proteasomal degradation of TGF‐β type I receptor (TβRI). LITATS1 interacts with TβRI and the E3 ligase SMURF2, promoting the cytoplasmic retention of SMURF2. Our findings highlight a protective function of LITATS1 in epithelial integrity maintenance through the attenuation of TGF‐β/SMAD signaling and EMT.

Mechanism of epithelial-mesenchymal transition in cancer and its regulation by natural compounds.

Epithelial-mesenchymal transition (EMT) is a complex process with a primordial role in cellular transformation whereby an epithelial cell transforms and acquires a mesenchymal phenotype. This transformation plays a pivotal role in tumor progression and self-renewal, and exacerbates resistance to apoptosis and chemotherapy. EMT can be initiated and promoted by deregulated oncogenic signaling pathways, hypoxia, and cells in the tumor microenvironment, resulting in a loss-of-epithelial cell polarity, cell-cell adhesion, and enhanced invasive/migratory properties. Numerous transcriptional regulators, such as Snail, Slug, Twist, and ZEB1/ZEB2 induce EMT through the downregulation of epithelial markers and gain-of-expression of the mesenchymal markers. Additionally, signaling cascades such as Wnt/β-catenin, Notch, Sonic hedgehog, nuclear factor kappa B, receptor tyrosine kinases, PI3K/AKT/mTOR, Hippo, and transforming growth factor-β pathways regulate EMT whereas they are often deregulated in cancers leading to aberrant EMT. Furthermore, noncoding RNAs, tumor-derived exosomes, and epigenetic alterations are also involved in the modulation of EMT. Therefore, the regulation of EMT is a vital strategy to control the aggressive metastatic characteristics of tumor cells. Despite the vast amount of preclinical data on EMT in cancer progression, there is a lack of clinical translation at the therapeutic level. In this review, we have discussed thoroughly the role of the aforementioned transcription factors, noncoding RNAs (microRNAs, long noncoding RNA, circular RNA), signaling pathways, epigenetic modifications, and tumor-derived exosomes in the regulation of EMT in cancers. We have also emphasized the contribution of EMT to drug resistance and possible therapeutic interventions using plant-derived natural products, their semi-synthetic derivatives, and nano-formulations that are described as promising EMT blockers.

Towards Regenerative Audiology: Immune Modulation of Adipose-Derived Mesenchymal Cells Preconditioned with Citric Acid-Coated Antioxidant-Functionalized Magnetic Nanoparticles.

Introduction and Background: Based on stem cells, bioactive molecules and supportive structures, regenerative medicine (RM) is promising for its potential impact on field of hearing loss by offering innovative solutions for hair cell rescue. Nanotechnology has recently been regarded as a powerful tool for accelerating the efficiency of RM therapeutic solutions. Adipose-derived mesenchymal cells (ADSCs) have already been tested in clinical trials for their regenerative and immunomodulatory potential in various medical fields; however, the advancement to bedside treatment has proven to be tedious. Innovative solutions are expected to circumvent regulatory and manufacturing issues related to living cell-based therapies. The objectives of the study were to test if human primary ADSCs preconditioned with magnetic nanoparticles coated with citric acid and functionalized with antioxidant protocatechuic acid (MNP-CA-PCA) retain their phenotypic features and if conditioned media elicit immune responses in vitro. MNP-CA-PCA was synthesized and characterized regarding size, colloidal stability as well as antioxidant release profile. Human primary ADSCs preconditioned with MNP-CA-PCA were tested for viability, surface marker expression and mesenchymal lineage differentiation potential. Conditioned media (CM) from ADSCs treated with MNP-CA-PCA were tested for Il-6 and IL-8 cytokine release using ELISA and inhibition of lectin-stimulated peripheral blood monocyte proliferation. Results: MNP-CA-PCA-preconditioned ADSCs display good viability and retain their specific mesenchymal stem cell phenotype. CM from ADSCs conditioned with MNP-CA-PCA do not display increased inflammatory cytokine release and do not induce proliferation of allergen-stimulated allogeneic peripheral blood monocytes in vitro. Conclusions: While further in vitro and in vivo tests are needed to validate these findings, the present results indicated that CM from ADSCs preconditioned with MNP-CA-PCA could be developed as possible cell-free therapies for rescuing auditory hair cells.

Arsenite Exposure to Human RPCs (HRTPT) Produces a Reversible Epithelial Mesenchymal Transition (EMT): In-Vitro and In-Silico Study.

The human kidney is known to possess renal progenitor cells (RPCs) that can assist in the repair of acute tubular injury. The RPCs are sparsely located as single cells throughout the kidney. We recently generated an immortalized human renal progenitor cell line (HRTPT) that co-expresses PROM1/CD24 and expresses features expected on RPCs. This included the ability to form nephrospheres, differentiate on the surface of Matrigel, and undergo adipogenic, neurogenic, and osteogenic differentiation. These cells were used in the present study to determine how the cells would respond when exposed to nephrotoxin. Inorganic arsenite (iAs) was chosen as the nephrotoxin since the kidney is susceptible to this toxin and there is evidence of its involvement in renal disease. Gene expression profiles when the cells were exposed to iAs for 3, 8, and 10 passages (subcultured at 1:3 ratio) identified a shift from the control unexposed cells. The cells exposed to iAs for eight passages were then referred with growth media containing no iAs and within two passages the cells returned to an epithelial morphology with strong agreement in differential gene expression between control and cells recovered from iAs exposure. Results show within three serial passages of the cells exposed to iAs there was a shift in morphology from an epithelial to a mesenchymal phenotype. EMT was suggested based on an increase in known mesenchymal markers. We found RPCs can undergo EMT when exposed to a nephrotoxin and undergo MET when the agent is removed from the growth media.

Resveratrol Modulates Chemosensitisation to 5-FU via β1-Integrin/HIF-1α Axis in CRC Tumor Microenvironment.

Frequent development of resistance to chemotherapeutic agents such as 5-flourouracil (5-FU) complicates the treatment of advanced colorectal cancer (CRC). Resveratrol is able to utilize β1-integrin receptors, strongly expressed in CRC cells, to transmit and exert anti-carcinogenic signals, but whether it can also utilize these receptors to overcome 5-FU chemoresistance in CRC cells has not yet been investigated. Effects of β1-integrin knockdown on anti-cancer capabilities of resveratrol and 5-FU were investigated in HCT-116 and 5-FU-resistant HCT-116R CRC tumor microenvironment (TME) with 3D-alginate as well as monolayer cultures. Resveratrol increased CRC cell sensitivity to 5-FU by reducing TME-promoted vitality, proliferation, colony formation, invasion tendency and mesenchymal phenotype including pro-migration pseudopodia. Furthermore, resveratrol impaired CRC cells in favor of more effective utilization of 5-FU by down-regulating TME-induced inflammation (NF-kB), vascularisation (VEGF, HIF-1α) and cancer stem cell production (CD44, CD133, ALDH1), while up-regulating apoptosis (caspase-3) that was previously inhibited by TME. These anti-cancer mechanisms of resveratrol were largely abolished by antisense oligonucleotides against β1-integrin (β1-ASO) in both CRC cell lines, indicating the particular importance of β1-integrin receptors for the 5-FU-chemosensitising effect of resveratrol. Lastly, co-immunoprecipitation tests showed that resveratrol targets and modulates the TME-associated β1-integrin/HIF-1α signaling axis in CRC cells. Our results suggest for the first time the utility of the β1-integrin/HIF-1α signaling axis related to chemosensitization and overcoming chemoresistance to 5-FU in CRC cells by resveratrol, underlining its potential supportive applications in CRC treatment.

Assessing the epithelial-to-mesenchymal plasticity in a small cell lung carcinoma (SCLC) and lung fibroblasts co-culture model.

The tumor microenvironment (TME) is the source of important cues that govern epithelial-to-mesenchymal transition (EMT) and facilitate the acquisition of aggressive traits by cancer cells. It is now recognized that EMT is not a binary program, and cancer cells rarely switch to a fully mesenchymal phenotype. Rather, cancer cells exist in multiple hybrid epithelial/mesenchymal (E/M) states responsible for cell population heterogeneity, which is advantageous for the ever-changing environment during tumor development and metastasis. How are these intermediate states generated and maintained is not fully understood. Here, we show that direct interaction between small cell lung carcinoma cells and lung fibroblasts induces a hybrid EMT phenotype in cancer cells in which several mesenchymal genes involved in receptor interaction with the extracellular matrix (ECM) and ECM remodeling are upregulated while epithelial genes such as E-cadherin remain unchanged or slightly increase. We also demonstrate that several core EMT-regulating transcription factors (EMT-TFs) are upregulated in cancer cells during direct contact with fibroblasts, as is Yes-associated protein (YAP1), a major regulator of the Hippo pathway. Further, we show that these changes are transient and reverse to the initial state once the interaction is disrupted. Altogether, our results provide evidence that tumor cells' direct contact with the fibroblasts in the TME initiates a signaling cascade responsible for hybrid E/M states of cancer cells. These hybrid states are maintained during the interaction and possibly contribute to therapy resistance and immune evasion, while interference with direct contact will result in slow recovery and switch to the initial states.

Boolean modeling of mechanosensitive epithelial to mesenchymal transition and its reversal

The significance of biophysical modulators of the epithelial to mesenchymal transition (EMT) is demonstrated by experiments that document full EMT on stiff, nano-patterned substrates in the absence of biochemical induction. Yet, current models focus on biochemical triggers of EMT without addressing its mechanosensitive nature. Here, we built a Boolean model of EMT triggered by mechanosensing- mitogen crosstalk. Our model reproduces epithelial, hybrid E/M and mesenchymal phenotypes, the role of autocrine TGFβ signaling in maintaining mesenchymal cells in the absence of external drivers, inhibition of proliferation by TGFβ, and its apoptotic effects on soft ECM. We offer testable predictions on the density-dependence of partial EMT, its molecular drivers, and the conflict between mitosis and hybrid E/M stability. Our model opens the door to modeling the effects of the biomechanical environment on cancer cell stemness linked to the hybrid E/M state, as well as the mutually inhibitory crosstalk between EMT and senescence.

Abstract P2-19-02: Androgen mediated signaling induces epithelial to mesenchymal transition phenotype in MDA-MB-453 breast cancer cells and human breast tumors

Abstract Background: Epithelial-mesenchymal transition (EMT) phenotype is a complex process and plays a central role in tumor progression, aggression, invasion, metastasis, and resistance to therapy. Role of androgen receptor (AR) and androgens in inducing EMT has been well established in experimental systems of prostate cancer. AR is widely expressed in all subtypes of breast cancer (BC) and is considered to have context dependent role based on the steroid hormone microenvironment. Previous studies have shown AR as the only sex steroid receptor detectable in BC metastases and in metastatic lesion. We investigated the role of androgens in driving the EMT phenotype and association of AR induced genes with EMT in BC tumors using public dataset. Methods: We treated AR positive breast cancer cell line MDA-MB-453 with the androgen, dihydrotestosterone (DHT) followed by AR antagonist bicalutamide (Bic) and examined the expression levels of AR induced genes by quantitative real time PCR (qPCR) and AR induced protein GCDFP-15 by western blot. AR driven genes (SEC14L2, C1orf116, FKBP5, UGT2B11, UGT2B28, KCNMA1, PIP and ABCC11) were identified by bioinformatic pipeline using a systematic bioinformatic approach from public microarray data sets derived from AR positive breast cancer cell lines (S Rajarajan et al, SABCS 2021). Mesenchymal phenotype of the cell lines under DHT/Bic was evaluated morphologically and expression levels of EMT markers (ZEB1, Slug, Vimentin) and E-cadherin was estimated by qPCR, western blot and immunofluorescence. Migratory potential of the cell line under treatment was evaluated by wound healing assay and proliferation was examined by the MTT assay. Association of AR induced genes and levels of enzymes involved in intracrinal testosterone metabolism (SRD5A1 & SRD5A3) with EMT in breast tumors was evaluated using transcript data from METABRIC database. EMT scores were derived from previous publications (Byers et al, 2013, Mak et al, 2016) and correlation was tested with AR induced genes. Results: The MDAMB-453 cell line was treated with 10nM DHT for 72hrs and this increased the expression of AR downstream protein GCDFP-15 by 31.47% (p=0.022) when compared to the control. Further, a significant increase in the expression levels of AR driven genes with a fold change >2 was observed in the DHT treated cells (p< 0.05). The expression of GCDP15 protein (p=0.028) and the AR downstream genes (p< 0.05) were significantly repressed upon treatment with bicalutamide. DHT treatment also showed a significant higher expression of EMT master regulator, SLUG (fold change>3, p=0.045) and a wound healing assay showed a 22% increase in migration (p=0.027). The expression of SLUG was significantly repressed (p=0.003) and the migratory ability of the DHT treated cells reduced upon treatment with bicalutamide (p=0.145). We also observed a significant loss of E-cadherin protein (by 23.65%; p=0.024) with DHT treatment and this was completely reversed upon treatment with bicalutamide (p=0.047). No significant change in proliferation was observed among the different treatment conditions. A significant positive correlation was observed between AR induced genes and the EMT scores (p< 0.05). Expression level of SRD5A3 was also positively correlated with EMT score (p=0.043) and AR induced genes (p< 0.05), except SEC14L2. Conclusion: Androgen receptor plays an important role in the biology of breast cancer and is considered a useful marker for prognosis. However, antiandrogen therapies haven’t seen the expected success in clinical trial settings. Our results support the controversial role played by AR in higher androgenic environment within breast cancer and warrant the consideration of the intratumoral levels of sex steroid hormones. Citation Format: Savitha Rajarajan, Snijesh VP, Madhumathy G Nair, Apoorva D, Chandrakala M, Vidya P Nimbalkar, Maalavika Pillai, Mohit Kumar Jolly, Jyothi S Prabhu. Androgen mediated signaling induces epithelial to mesenchymal transition phenotype in MDA-MB-453 breast cancer cells and human breast tumors [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-19-02.

Abstract P4-08-25: Unravelling the role of human endogenous retrovirus K (HERV-K) in inducible nitric oxide synthase (iNOS) mediated triple negative breast cancer progression

Abstract Human endogenous retrovirus K (HERV-K) belongs to a family of endogenous retroviruses that are present in our genome with similarities to present day exogenous retroviruses. This virus can express several proteins but our knowledge of HERV-K expression in human cancers is mainly limited to the envelope (Env) protein. Elevated HERV-K env protein expression has been shown in breast cancer both in in vitro and in vivo studies. This project aimed to decipher mechanisms of HERV-K induction in triple negative breast cancer (TNBC), and the impact of HERV-K targeting shRNA mediated knockdown on TNBC characteristics including cell migration, invasion and proliferative capacity in 2D and 3D cell culture models. Our results show that a role for inducible nitric oxide synthase (iNOS) in the induction of HERV-K in TNBC cell lines. RNA seq and bioinformatics analysis was performed to identify key molecular processes regulated by HERV-K and nitric oxide (NO) in MDA-MB-231 TNBC cells. Reduced rates of migration, invasion and proliferation in HERV-K knockdowns points towards the essential role of HERV-K in tumorigenesis and metastasis. HERV-K knockdown also modulated key gene expression signatures traditionally associated with the basal and mesenchymal phenotypes in breast cancer, cellular senescence and MHC class gene regulation. The co-expression of iNOS and HERV-K was assessed in over 150 TNBC cases and the association with patient outcomes assessed. Taken together, our findings indicate that NO and HERV-K may be a useful molecular target for the treatment of TNBC. Citation Format: Dibyangana Bhattacharyya, Eoin Dervan, Sharon Glynn, Grace Callagy. Unravelling the role of human endogenous retrovirus K (HERV-K) in inducible nitric oxide synthase (iNOS) mediated triple negative breast cancer progression [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-08-25.

Regulation of endothelial-to-mesenchymal transition by histone deacetylase 3 posttranslational modifications in neointimal hyperplasia.

Endothelial-to-mesenchymal transition (EndMT) is the process by which endothelial cells lose their specific markers and acquire mesenchymal or myofibroblastic phenotypes. Studies have demonstrated the importance of endothelial-derived vascular smooth muscle cells (VSMCs) through EndMT in neointimal hyperplasia. Histone deacetylases (HDACs) are epigenetic modification enzymes involved in the epigenetic control of important cellular functions. Recent studies found that HDAC3, a class I HDAC, causes posttranslational modifications, including deacetylation and decrotonylation. However, the effect of HDAC3 on EndMT in neointimal hyperplasia via posttranslational modifications remains to be seen. Therefore, we investigated the effects of HDAC3 on EndMT in carotid artery-ligated mice and human umbilical vein endothelial cells (HUVECs) and the underlying posttranslational modifications. HUVECs were treated with transforming growth factor (TGF)-β1 or the inflammatory cytokine tumor necrosis factor (TNF)-α at different concentrations and durations. In HUVECs, HDAC3 expression, the expression of endothelial and mesenchymal markers, and posttranslational modifications were analyzed with Western blotting, quantitative real-time polymerase chain reaction (PCR), and immunofluorescence. C57BL/6 mice underwent left carotid artery ligation. Mice were treated with the HDAC3-selective inhibitor RGFP966 (10 mg/kg, i.p.) from 1 day before to 14 days after ligation. Then, the sections of the carotid arteries were examined histologically using hematoxylin and eosin (HE) and immunofluorescence staining. The carotid arteries from other mice were examined for the expression of EndMT markers and inflammatory cytokines. Furthermore, the acetylation and crotonylation of carotid arteries were immunostained in mice. In HUVECs, TGF-β1 and TNF-α induced EndMT by decreasing CD31 expression and increasing α-smooth muscle actin expression. TGF-β1 and TNF-α also upregulated HDAC3 expression in HUVECs. The in vivo study in mice indicated that RGFP966 significantly alleviated neointimal hyperplasia of the carotid artery compared with vehicle treatment. Furthermore, RGFP966 suppressed EndMT and the inflammatory response in carotid artery-ligated mice. Further investigation revealed that HDAC3 regulated EndMT by posttranslational modifications of deacetylation and decrotonylation. These results suggest that HDAC3 regulates EndMT in neointimal hyperplasia through posttranslational modifications.

Abstract P1-05-09: Targeting treatment to tumor response: demonstration of response monitoring with subsequent impact on treatment choices in real time utilizing a novel technology

Abstract Breast cancers, both early and advanced, are heterogeneous causing differential responses to targeted therapy. Explosion in targeted treatment choices requires real time assessment of tumor characteristics in patients initially and over time. A dynamic detection system, not a static pathology specimen, is required for continuous profiling while treatment changes; hence, the interest in circulating tumor cells (CTCs). Our novel QCDx br™ system analyzes all nucleated cells from a blood sample aliquot, morphologically intact and immobilized in hydrogel, after multiplex, immunofluorescent (IF) staining. We characterize increased numbers of CTCs (nucleated, CD45-negative cells) as single cells, in clusters and in connection with circulating inflammatory cells, stained with two, separate IF marker cocktails, denoting (1) epithelial (EpCAM, Cytokeratin CK), mesenchymal (Vimentin VIM) phenotypes and (2) therapeutic HER2, ER and TROP2 targets which are the basis for targeted therapy in breast cancer. In the ongoing, prospective CLINBREAC trial, we enrolled to date 9 neoadjuvant (early stage, ES) and 21 metastatic (late stage, LS) breast cancer patients, collecting 7.5 ml of blood at 3-month intervals or at change of therapy. We are now out over 2 years with the earliest ES and LS patients showing changes in CTCs with disease progression and in response to treatment, often pre-dating changes seen in follow up biopsies. Detection of HER2+ CTCs was of particular interest in patients with HER2 low cancers¬ (1+ or 2+). Results presented here, contain the more complete datasets from 8 ES and 11 LS patients. QCDx br™ detected CTCs in all 19 Stage I-IV patients that could exceed 100 CTCs/2500 nucleated cells in LS and 50 CTCs/2500 nucleated cells in ES patients. The table shows count averages of CTCs/2500 nucleated cells detected by different IF markers. Of note, CTCs showed combinations of IF markers (hybrid cells). For example, CTCs expressed both VIM and CK indicating epithelial to mesenchymal transition (EMT) phenotype, which may signify higher metastatic potential. ER+ CTC were seen in LS, not ES patients. All ES patients including those with HER2 low tumors, showed HER2+ CTCs. Of note, not included in the table are two, triple-positive patients with oligo-metastatic disease now 4 and 10 years out from diagnosis without evidence of disease and on maintenance HER2 and ER-directed therapy. No CTCs are seen at their first data point. We were unable to detect CTCs in 13 healthy volunteers. In ES patients, CTC numbers did not associate with tumor size, nodal involvement, ER or HER2 status. For example, one TNBC patient with a T3 tumor and positive nodes had some of the lowest numbers of CTCs. The more complete quantification of the LS patients is in process. As development of QCDx br™ continues, multiplex IF staining of 12+ markers per CTC and identification of single CTC mutational changes is expected. This powerful technology enables targeted treatment decisions with specific drugs resulting in maximal responses. Average CTC counts/2500 nucleated cells detected by phenotypic and therapeutic IF cocktails Citation Format: Susan Tannenbaum, Emily Hsu, jasmin Hundal, Amber Wilkes, Austin Fergusson, Fahmy Mamuya, Triantafyllos Tafas. Targeting treatment to tumor response: demonstration of response monitoring with subsequent impact on treatment choices in real time utilizing a novel technology [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-05-09.

Abstract P5-11-03: Knockdown of TMEM45A regulates malignant progression of triple-negative breast cancer by inhibiting TGF-β/Smad signaling pathway-mediated EMT

Abstract Objectives: The incidence of breast cancer has jumped to first place in the global malignant tumor. As an essential component of the TMEM family, TMEM45A is abnormally highly expressed in some malignant tumors, and plays a role in promoting and regulating the occurrence and development of tumors. This study analyzed the expression of TMEM45A in breast cancer tissues and breast cancer cell lines, and explored the relationship with clinical subtypes. To examine the effects of TMEM45A on TNBC cell proliferation, migration, invasion and other biological functions, and to preliminarily clarify the molecular mechanism of TMEM45A regulating the epithelial-mesenchymal transition of TNBC cell lines. Methods: 1. Download and analyze the TCGA database, analyze the difference in the expression of TMEM45A in normal breast tissue and different subtypes of breast cancer tissue, and detect the protein expression level of TMEM45A in 8 pairs of cancer tissues and adjacent tissues by western blot experiment. 2. Detection of TMEM45A protein expression in normal breast epithelial cell line MCF10A and five breast cancer cell lines (MCF-7, MDA-MB-231, BT-549, MDA-MB-468, SK-BR-3) by western blot experiment. 3. Using small interfering RNA technology to down-regulate the protein expression levels of MDA-MB-231 and BT-549 TNBC cell lines with relatively high TMEM45A expression. The changes in cell proliferation ability were detected by CCK8 assay and clone formation assay, and the changes in cell migration ability and invasion ability were detected by wound healing assay and transwell assay, respectively. 4. After down-regulating TMEM45A in two TNBC cell lines, the expression changes of epithelial cell phenotype marker E-cadherin, mesenchymal phenotype marker N-cadherin, Vimentin, and critical molecules in TGF-β/Smad signal transduction pathway (TGFβ1, Smad2, Smad3, p-Smad2, p-Smad3) were detected by western blot experiment. Results: 1. Based on the TCGA database, the results showed that the expression level of TMEM45A mRNA in breast cancer was significantly higher than in normal breast tissue. The expression level of TMEM45A mRNA in any breast cancer subtype was higher than that in normal breast tissue, and it was the highest in the TNBC subtype. In the results of western blot experiments of clinical breast cancer specimens, the expression of TMEM45A in breast cancer tissues was significantly higher than that in the corresponding adjacent tissues, which further confirmed the reliability of the results of the TCGA database. 2. In normal breast epithelial cell line MCF10A and five breast cancer cell lines, MCF10A has the lowest expression level of TMEM45A protein. Among the five breast cancer cell lines, MDA-MB-231 had the highest expression of TMEM45A, followed by BT-549. 3. CCK8 assay, clone formation assay, wound healing assay and transwell assay showed that down-regulating TMEM45A protein levels in the two TNBC cell lines could significantly reduce cell proliferation, migration and invasion abilities. 4. After down-regulating TMEM45A protein levels in two TNBC cell lines, EMT-related indicators E-cadherin protein expression levels increased, N-cadherin and Vimentin protein expressions decreased, and the expression levels of essential protein molecules Smad2 and Smad3 in the TGF-β/Smad signal transduction pathway did not change significantly, while p-Smad2, p-Smad3 and TGF-β1 protein expressions decreased. Conclusions: TMEM45A is relatively highly expressed in breast cancer tissues and cell lines, especially in the subtype of TNBC. Down-regulation of TMEM45A expression can inhibit the proliferation, migration and invasion of TNBC cell lines. Mechanistically, TMEM45A may reverse EMT by inhibiting the activity of the TGF-β/Smad pathway. Citation Format: Yingkun Xu, Shengchun Liu. Knockdown of TMEM45A regulates malignant progression of triple-negative breast cancer by inhibiting TGF-β/Smad signaling pathway-mediated EMT [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-11-03.

The Developmental Origins of Cancer: A Review of the Genes Expressed in Embryonic Cells with Implications for Tumorigenesis

Tumorigenesis, which involves the uncontrolled proliferation and differentiation of cells, has been observed to imitate a variety of pathways vital to embryonic development, motivating cancer researchers to explore the genetic origins of these pathways. The pluripotency gene regulatory network is an established collection of genes that induces stemness in embryonic cells. Dysregulation in the expression genes of the pluripotency gene networks including OCT4, SOX2, NANOG and REX1 have been implicated in tumor development, and have been observed to result in poorer patient outcomes. The p53 pathway is a highly important regulatory process in a multitude of cell types, including embryonic, and the tumor suppressor gene TP53 is widely regarded as being one of the most important genes involved in tumorigenesis. Dysregulations in TP53 expression, along with altered expression of developmentally originating p53 regulators such as MDM2 and MDM4 have been implicated in various cancers, leading to poorer prognosis. Epithelial-mesenchymal transition (EMT), the process allowing epithelial cells to undergo biochemical changes to mesenchymal phenotypes, also plays a vital role in the fate of both embryonic and neoplastic cells. Genes that regulate EMT such as Twist1, SOX9 and REX1 have been associated with an increased occurrence of EMT in cancer cells, leading to enhanced cell stemness, proliferation and metastasis. The class of RNA that does not encode for proteins, known as non-coding RNA, has been implicated in a variety of cellular processes and emerging research has shown that its dysregulation can lead to uncontrolled cell proliferation and differentiation. Genes that have been shown to play a role in this dysregulation include PIWIL1, LIN28A and LIN28B, and have been associated with poorer patient outcomes and more aggressive cancer subtypes. The identification of these developmentally regulated genes in tumorigenesis has proved to play an advantageous role in cancer diagnosis and prognosis, and has provided researchers with a multitude of new target mechanisms for novel chemotherapeutic research.

Photothermal Attenuation of Cancer Cell Stemness, Chemoresistance, and Migration Using CD44-Targeted MoS2 Nanosheets.

Cancer stem-like cells (CSCs) play key roles in chemoresistance, tumor metastasis, and clinical relapse. However, current CSC inhibitors lack specificity, efficacy, and applicability to different cancers. Herein, we introduce a nanomaterial-based approach to photothermally induce the differentiation of CSCs, termed "photothermal differentiation", leading to the attenuation of cancer cell stemness, chemoresistance, and metastasis. MoS2 nanosheets and a moderate photothermal treatment were applied to target a CSC surface receptor (i.e., CD44) and modulate its downstream signaling pathway. This treatment forces the more stem-like cancer cells to lose the mesenchymal phenotype and adopt an epithelial, less stem-like state, which shows attenuated self-renewal capacity, more response to anticancer drugs, and less invasiveness. This approach could be applicable to various cancers due to the broad availability of the CD44 biomarker. The concept of using photothermal nanomaterials to regulate specific cellular activities driving the differentiation of CSCs offers a new avenue for treating refractory cancers.

Expression of EMT-related genes in lymph node metastasis in endometrial cancer: a TCGA-based study

BackgroundEndometrial cancer (EC) with metastasis in pelvic/para-aortic lymph nodes suggests an unsatisfactory prognosis. Nevertheless, there is still rare literature focusing on the role of epithelial-mesenchymal transition (EMT) in lymph node metastasis (LNM) in EC.MethodsTranscriptional data were derived from the TCGA database. Patients with stage IA–IIIC2 EC were included, constituting the LN-positive and LN-negative groups. To evaluate the extent of EMT, an EMT signature composed of 315 genes was adopted. The EMT-related genes (ERGs) were obtained from the dbEMT2 database, and the differentially expressed ERGs (DEERGs) between these two groups were screened. On the basis of DEERGs, pathway analysis was carried out. We eventually adopted the logistic regression model to build an ERG-based gene signature with predictive value for LNM in EC.ResultsA total of 498 patients were included, with 75 in the LN-positive group. Median EMT score of tumor tissues from LN-negative group was − 0.369, while that from the LN-positive group was − 0.296 (P < 0.001), which clearly exhibited a more mesenchymal phenotype for LNM cases on the EMT continuum. By comparing expression profiles, 266 genes were identified as DEERGs, in which 184 were upregulated and 82 were downregulated. In pathway analysis, various EMT-related pathways were enriched. DEERGs shared between molecular subtypes were comparatively few. The ROC curve and logistic regression analysis screened 7 genes with the best performance to distinguish between the LN-positive and LN-negative group, i.e., CIRBP, DDR1, F2RL2, HOXA10, PPARGC1A, SEMA3E, and TGFB1. A logistic regression model including the 7-gene-based risk score, age, grade, myometrial invasion, and histological subtype was built, with an AUC of 0.850 and a favorite calibration (P = 0.074). In the validation dataset composed of 83 EC patients, the model exhibited a satisfactory predictive value and was well-calibrated (P = 0.42).ConclusionThe EMT status and expression of ERGs varied in LNM and non-LNM EC tissues, involving multiple EMT-related signaling pathways. Aside from that, the distribution of DEERGs differed among molecular subtypes. An ERG-based gene signature including 7 DEERGs exhibited a desirable predictive value for LNM in EC, which required further validation based upon clinical specimens in the future.

Regulation of the Epithelial to Mesenchymal Transition in Osteosarcoma.

The epithelial to mesenchymal transition (EMT) is a cellular process that has been linked to the promotion of aggressive cellular features in many cancer types. It is characterized by the loss of the epithelial cell phenotype and a shift to a more mesenchymal phenotype and is accompanied by an associated change in cell markers. EMT is highly complex and regulated via multiple signaling pathways. While the importance of EMT is classically described for carcinomas-cancers of epithelial origin-it has also been clearly demonstrated in non-epithelial cancers, including osteosarcoma (OS), a primary bone cancer predominantly affecting children and young adults. Recent studies examining EMT in OS have highlighted regulatory roles for multiple proteins, non-coding nucleic acids, and components of the tumor micro-environment. This review serves to summarize these experimental findings, identify key families of regulatory molecules, and identify potential therapeutic targets specific to the EMT process in OS.

Biophysical Parameters Can Induce Epithelial-to-Mesenchymal Phenotypic and Genotypic Changes in HT-29 Cells: A Preliminary Study.

Epithelial to mesenchymal transition (EMT) in cancer is the process described where cancer epithelial cells acquire mesenchymal properties which can lead to enhanced invasiveness. Three-dimensional cancer models often lack the relevant and biomimetic microenvironment parameters appropriate to the native tumour microenvironment thought to drive EMT. In this study, HT-29 epithelial colorectal cells were cultivated in different oxygen and collagen concentrations to investigate how these biophysical parameters influenced invasion patterns and EMT. Colorectal HT-29 cells were grown in physiological hypoxia (5% O2) and normoxia (21% O2) in 2D, 3D soft (60 Pa), and 3D stiff (4 kPa) collagen matrices. Physiological hypoxia was sufficient to trigger expression of markers of EMT in the HT-29 cells in 2D by day 7. This is in contrast to a control breast cancer cell line, MDA-MB-231, which expresses a mesenchymal phenotype regardless of the oxygen concentration. In 3D, HT-29 cells invaded more extensively in a stiff matrix environment with corresponding increases in the invasive genes MMP2 and RAE1. This demonstrates that the physiological environment can directly impact HT-29 cells in terms of EMT marker expression and invasion, compared to an established cell line, MDA-MB-231, which has already undergone EMT. This study highlights the importance of the biophysical microenvironment to cancer epithelial cells and how these factors can direct cell behaviour. In particular, that stiffness of the 3D matrix drives greater invasion in HT-29 cells regardless of hypoxia. It is also pertinent that some cell lines (already having undergone EMT) are not as sensitive to the biophysical features of their microenvironment.

Nodakenin Induces ROS-Dependent Apoptotic Cell Death and ER Stress in Radioresistant Breast Cancer

Angelica gigas exerts powerful anti-tumor and anti-cancer effects in various cancer cell types. However, there have been few studies regarding the anti-cancer effect of nodakenin, a bioactive compound of Angelica gigas, in vivo and in vitro on breast cancers. I found that nodakenin, in a concentration-dependent manner, inhibits breast cancer cell viability and decreases the tumor volume in mice. Additionally, nodakenin induces caspase-3-dependent apoptosis in breast cancer cells; however, the combination of Z-VAD-FMK and nodakenin suppresses the caspase-3-dependent apoptotic cell death. Furthermore, nodakenin mediates apoptotic cell death via the PERK-mediated signaling pathway and calcium (Ca2+) release, and nodakenin combined with thapsigargin induces synergistic cell death by inhibiting sarco/endoplasmic reticulum (ER) Ca2+-ATPase. However, knockdown of PERK or CHOP inhibits Ca2+ generation and caspase-dependent apoptosis in nodakenin-treated breast cancer cells. Nodakenin induces ROS and Ca2+ generation, ER stress, and apoptotic cell death; however, the knockdown of Nox4 inhibits ROS generation and ER stress- and caspase-dependent apoptotic cell death. In addition, nodakenin combined with radiation overcomes radioresistance in radioresistant breast cancer cells by suppressing epithelial-mesenchymal transition phenotypes, including the decrease in E-cadherin and the increase in N-cadherin and vimentin. Therefore, these findings indicate that nodakenin may be a novel therapeutic strategy for breast cancers.

USP7 imparts partial EMT state in colorectal cancer by stabilizing the RNA helicase DDX3X and augmenting Wnt/β-catenin signaling

Epithelial mesenchymal transition (EMT) is a fundamental and highly regulated process that is normally observed during embryonic development and tissue repair but is deregulated during advanced cancer. Classically, through the process of EMT, cancer cells gradually transition from a predominantly epithelial phenotype to a more invasive mesenchymal phenotype. Increasing studies have, however, brought into light the existence of unique intermediary states in EMT, often referred to as partial EMT states. Through our studies we have found the deubiquitinase USP7 to be strongly associated with the development of such a partial EMT state in colon cancer cells, characterized by the acquisition of mesenchymal characteristics but without the reduction in epithelial markers. We found USP7 to be overexpressed in colon adenocarcinomas and to be closely associated with advancing tumor stage. We found that functional inhibition or knockdown of USP7 is associated with a marked reduction in mesenchymal markers and in overall migration potential of cancer cells. Starting off with a proteomics-based approach we were able to identify and later on verify the DEAD box RNA helicase DDX3X to be an interacting partner of USP7. We then went on to show that USP7, through the stabilization of DDX3X, augments Wnt/β-catenin signaling, which has previously been shown to be greatly associated with colorectal cancer cell invasiveness. Our results indicate USP7 as a novel key player in establishing a partial mesenchymal phenotype in colorectal cancer.

Genomic and microenvironmental heterogeneity shaping epithelial-to-mesenchymal trajectories in cancer

The epithelial to mesenchymal transition (EMT) is a key cellular process underlying cancer progression, with multiple intermediate states whose molecular hallmarks remain poorly characterised. To fill this gap, we present a method to robustly evaluate EMT transformation in individual tumours based on transcriptomic signals. We apply this approach to explore EMT trajectories in 7180 tumours of epithelial origin and identify three macro-states with prognostic and therapeutic value, attributable to epithelial, hybrid E/M and mesenchymal phenotypes. We show that the hybrid state is relatively stable and linked with increased aneuploidy. We further employ spatial transcriptomics and single cell datasets to explore the spatial heterogeneity of EMT transformation and distinct interaction patterns with cytotoxic, NK cells and fibroblasts in the tumour microenvironment. Additionally, we provide a catalogue of genomic events underlying distinct evolutionary constraints on EMT transformation. This study sheds light on the aetiology of distinct stages along the EMT trajectory, and highlights broader genomic and environmental hallmarks shaping the mesenchymal transformation of primary tumours.