Epithelial-mesenchymal-transition-inducing transcription factors: new targets for tackling chemoresistance in cancer?

Desulfovibrio vulgaris flagellin exacerbates colorectal cancer through activating LRRC19/TRAF6/TAK1 pathway

The initiation and progression of colorectal cancer (CRC) are intimately associated with genetic, environmental and biological factors. Desulfovibrio vulgaris (DSV), a sulfate-reducing bacterium, has been found excessive growth in CRC patients, suggesting a potential role in carcinogenesis. However, the precise mechanisms underlying this association remain incompletely understood. We have found Desulfovibrio was abundant in high-fat diet-induced Apcmin/+ mice, and DSV, a member of Desulfovibrio, triggered colonocyte proliferation of germ-free mice. Furthermore, the level of DSV progressively rose from healthy individuals to CRC patients. Flagella are important accessory structures of bacteria, which can help them colonize and enhance their invasive ability. We found that D. vulgaris flagellin (DVF) drove the proliferation, migration, and invasion of CRC cells and fostered the growth of CRC xenografts. DVF enriched the epithelial-mesenchymal transition (EMT)-associated genes and characterized the facilitation of DVF on EMT. Mechanistically, DVF induced EMT through a functional transmembrane receptor called leucine-rich repeat containing 19 (LRRC19). DVF interacted with LRRC19 to modulate the ubiquitination of tumor necrosis factor receptor-associated factor (TRAF)6, rather than TRAF2. This interaction drove the ubiquitination of pivotal molecule TAK1, further enhancing its autophosphorylation and ultimately contributing to EMT. Collectively, DVF interacts with LRRC19 to activate the TRAF6/TAK1 signaling pathway, thereby promoting the EMT of CRC. These data shed new light on the role of gut microbiota in CRC and establish a potential clinical therapeutic target.

Longitudinal single-cell multiomic atlas of high-risk neuroblastoma reveals chemotherapy-induced tumor microenvironment rewiring

High-risk neuroblastoma, a leading cause of pediatric cancer mortality, exhibits substantial intratumoral heterogeneity, contributing to therapeutic resistance. To understand tumor microenvironment evolution during therapy, we longitudinally profiled 22 patients with high-risk neuroblastoma before and after induction chemotherapy using single-nucleus RNA and ATAC sequencing and whole-genome sequencing. This revealed profound shifts in tumor and immune cell subpopulations after therapy and identified enhancer-driven transcriptional regulators of neuroblastoma neoplastic states. Poor outcome correlated with proliferative and metabolically active neoplastic states, whereas more differentiated neuronal-like states predicted better prognosis. Proportions of mesenchymal neoplastic cells increased after therapy and a high proportion correlated with a poorer chemotherapy response. Macrophages significantly expanded towards pro-angiogenic, immunosuppressive and metabolic phenotypes. We identified paracrine signaling networks and validated the HB-EGF-ERBB4 axis between macrophage and neoplastic subsets, which promoted tumor growth through the induction of ERK signaling. These findings collectively reveal intrinsic and extrinsic regulators of therapy response in high-risk neuroblastoma.

UGCG promotes chemoresistance and breast cancer progression via NF-κB and Wnt/β-catenin pathway activation

BACKGROUND

Taxane-based chemotherapy is the primary treatment for triple-negative breast cancer (TNBC), yet clinical outcomes remain unsatisfactory due to the persistence of chemoresistance. Identifying key factors that contribute to chemoresistance and understanding the associated molecular mechanisms is therefore essential.

METHOD

The GEO databases were utilized to pinpoint factors related to chemoresistance, which were subsequently validated using clinical tissue samples. The role of UGCG in the malignant progression and chemoresistance of TNBC was assessed through various functional assays. Western blotting, qRT-PCR, and immunohistochemistry were employed to investigate the signaling pathways associated with UGCG in TNBC.

RESULTS

UGCG expression was notably elevated in chemoresistant breast cancer tissues and cells, as identified in GEO databases and confirmed through immunohistochemistry. Additionally, findings from our cohorts indicated that higher levels of UGCG expression correlated with a lower rate of pathological complete response (pCR), suggesting it could serve as an independent predictor of chemotherapy effectiveness. Gain- and loss-of-function experiments demonstrated that UGCG enhanced the proliferation, metastasis, and stemness of breast cancer cells. Furthermore, treatment with paclitaxel or docetaxel resulted in increased UGCG expression, which in turn reduced chemotherapy-induced cell apoptosis and improved drug resistance and metastatic capabilities. Mechanistically, UGCG was found to amplify the activation of NF-κB and Wnt/β-catenin pathways, and the use of inhibitors targeting these pathways diminished the UGCG-induced malignant effects.

CONCLUSION

Our findings underscore the significant role of UGCG in the chemoresistance and progression of breast cancer, suggesting it as a predictive biomarker and potential therapeutic target to combat chemoresistance in this disease.

The mechanism underlying metastasis in triple-negative breast cancer: focusing on the interplay between ferroptosis, epithelial-mesenchymal transition, and non-coding RNAs

Triple-negative breast cancer (TNBC) is a type of breast cancer with lack the expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). It is the most aggressive breast cancer and the most difficult to treat due to its poor response to treatments and extremely invasive characteristics. The typical treatment for TNBC frequently results in relapse because of the lack of particular treatment choices. It is urgent to focus on identifying a workable and effective target for the treatment of TNBC. Cancer metastasis is significantly influenced by epithelial-mesenchymal transition (EMT). Ferroptosis is an iron-dependent cell death form, and changes its key factor to affect the proliferation and metastasis of TNBC. Several reports have established associations between EMT and ferroptosis in TNBC metastasis. Furthermore, non-coding RNA (ncRNA), which has been previously described, can also control cancer cell death and metastasis. Thus, in this review, we summarize the correlation and pathways among the ferroptosis, EMT, and ncRNAs in TNBC metastasis. Also, aim to find out a novel strategy for TNBC treatment through the ncRNA-ferroptosis-EMT axis.

Ferroptosis and its relationship with cancer

Marked by iron buildup and lipid peroxidation, ferroptosis is a relatively new regulatory cell death (RCD) pathway. Many diseases like cancer, myocardial ischemia-reperfusion injury (MIRI), neurological disorders and acute renal failure (AKI) are corelated with ferroptosis. The main molecular processes of ferroptosis discovered yet will be presented here, along with the approaches in which it interacts with tumour-associated signaling pathways and its uses in systemic therapy, radiation therapy, and immunotherapy managing tumors.

Long non-coding RNAs as the pivotal regulators of epithelial mesenchymal transition through WNT/β-catenin signaling pathway in tumor cells

Tumor cell invasion is considered as one of the main therapeutic challenges in cancer patients, which leads to distant metastasis and reduced prognosis. Therefore, investigation of the factors involved in tumor cell invasion improves the therapeutic methods to reduce tumor metastasis. Epithelial-mesenchymal transition (EMT) process has a pivotal role in tumor cell invasion and metastasis, during which tumor cells gain the invasive ability by losing epithelial characteristics and acquiring mesenchymal characteristics. WNT/β-catenin signaling pathway has a key role in tumor cell invasion by regulation of EMT process. Long non-coding RNAs (lncRNAs) have also an important role in EMT process through the regulation of WNT/β-catenin pathway. Deregulation of lncRNAs is associated with tumor metastasis in different tumor types. Therefore, in the present review, we investigated the role of lncRNAs in EMT process and tumor cell invasion through the regulation of WNT/β-catenin pathway. It has been reported that lncRNAs mainly induced the EMT process and tumor cell invasion through the activation of WNT/β-catenin pathway. LncRNAs that regulate the WNT/β-catenin mediated EMT process can be introduced as the prognostic markers as well as suitable therapeutic targets to reduce the tumor metastasis in cancer patients.

Diallyl disulfide antagonizes DJ-1 mediated proliferation, epithelial-mesenchymal transition, and chemoresistance in gastric cancer cells

Diallyl disulfide (DADS), an organic component of allicin abstracted from garlic, possesses multi-target antitumor activity. DJ-1 performs a vital function in promoting AKT aberrant activation via down-regulating phosphatase and tensin homologue (PTEN) in tumors. It is unknown the involvement of DJ-1 in epithelial-mesenchymal transition (EMT) of gastric cancer (GC) cells. The purpose of this study is to investigate whether diallyl disulfide (DADS) intervenes in the role of DJ-1 in GC. Based on the identification that the correlation between high DJ-1 and low PTEN expression in GC was implicated in clinical progression, we illuminated that down-regulation of DJ-1 by DADS aided in an increase in PTEN expression and a decrease in phosphorylated AKT levels, which was in line with the results manifested in the DJ-1 knockdown and overexpressed cells, concurrently inhibiting proliferation, EMT, migration, and invasion. Furthermore, the antagonistic effects of DADS on DJ-1 were observed in in vivo experiments. Additionally, DADS mitigated the DJ-1-associated drug resistance. The current study revealed that DJ-1 is one of potential targets for DADS, which hopefully provides a promising strategy for prevention and adjuvant chemotherapy of GC.

CYR61 confers chemoresistance by upregulating survivin expression in triple-negative breast cancer

Cysteine-rich angiogenic inducer 61 (CYR61) is a protein from the CCN family of matricellular proteins that play diverse regulatory roles in the extracellular matrix. CYR61 is involved in cell adhesion, migration, proliferation, differentiation, apoptosis, and senescence. Here, we show that CYR61 induces chemoresistance in triple-negative breast cancer (TNBC). We observed that CYR61 is overexpressed in TNBC patients, and CYR61 expression correlates negatively with the survival of patients who receive chemotherapy. CYR61 knockdown reduced cell migration, sphere formation and the cancer stem cell (CSC) population and increased the chemosensitivity of TNBC cells. Mechanistically, CYR61 activated Wnt/β-catenin signaling and increased survivin expression, which are associated with chemoresistance, the epithelial-mesenchymal transition, and CSC-like phenotypes. Altogether, our study demonstrates a novel function of CYR61 in chemotherapy resistance in breast cancer.

TGF-β Modulated Pathways in Colorectal Cancer: New Potential Therapeutic Opportunities

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide, with 20% of patients presenting with metastatic disease at diagnosis. TGF-β signaling plays a crucial role in various cellular processes, including growth, differentiation, apoptosis, epithelial-mesenchymal transition (EMT), regulation of the extracellular matrix, angiogenesis, and immune responses. TGF-β signals through SMAD proteins, which are intracellular molecules that transmit TGF-β signals from the cell membrane to the nucleus. Alterations in the TGF-β pathway and mutations in SMAD proteins are common in metastatic CRC (mCRC), making them critical factors in CRC tumorigenesis. This review first analyzes normal TGF-β signaling and then investigates its role in CRC pathogenesis, highlighting the mechanisms through which TGF-β influences metastasis development. TGF-β promotes neoangiogenesis via VEGF overexpression, pericyte differentiation, and other mechanisms. Additionally, TGF-β affects various elements of the tumor microenvironment, including T cells, fibroblasts, and macrophages, promoting immunosuppression and metastasis. Given its strategic role in multiple processes, we explored different strategies to target TGF-β in mCRC patients, aiming to identify new therapeutic options.

An update on the molecular mechanisms of ZFAS1 as a prognostic, diagnostic, or therapeutic biomarker in cancers

Zinc finger antisense 1 (ZFAS1), a newly discovered long noncoding RNA, is expressed in various tissues and organs and has been introduced an oncogenic gene in human malignancies. In various cancers, ZFAS1 regulates apoptosis, cell proliferation, the cell cycle, migration, translation, rRNA processing, and spliceosomal snRNP assembly; targets signaling cascades; and interacts with transcription factors via binding to key proteins and miRNAs, with conflicting findings on its effect on these processes. ZFAS1 is elevated in different types of cancer, like colorectal, colon, osteosarcoma, and gastric cancer. Considering the ZFAS1 expression pattern, it also has the potential to be a diagnostic or prognostic marker in various cancers. The current review discusses the mode of action of ZFAS1 in various human cancers and its regulation function related to chemoresistance comprehensively, as well as the potential role of ZFAS1 as an effective and noninvasive cancer-specific biomarker in tumor diagnosis, prognosis, and treatment. We expected that the current review could fill the current scientific gaps in the ZFAS1-related cancer causative mechanisms and improve available biomarkers.

CK2α-mediated phosphorylation of GRP94 facilitates the metastatic cascade in triple-negative breast cancer

Distant metastasis is a significant hallmark affecting to the high death rate of patients with triple-negative breast cancer (TNBC). Thus, it is crucial to identify and develop new therapeutic strategies to hinder cancer metastasis. While emerging studies have hinted a pivotal role of glucose-regulated protein 94 (GRP94) in tumorigenesis, the exact biological functions and molecular mechanisms of GRP94 in modulating cancer metastasis remain to be elucidated. Our study demonstrated an increased expression of GRP94 in TNBC correlated with metastatic progression and unfavorable prognosis in patients. Functionally, we identified that GRP94 depletion significantly diminished TNBC tumorigenesis and subsequent lung metastasis. In contrast, GRP94 overexpression exacerbated the invasiveness, migration, and lung metastasis of non-TNBC cells. Mechanistically, we found that casein kinase 2 alpha (CK2α) active in advanced breast cancer phosphorylated GRP94 at a conserved serine 306 (S306) residue. This phosphorylation increased the stability of GRP94 and enhanced its interaction with LRP6, leading to activation of canonical Wnt signaling. From a therapeutic standpoint, we found that benzamidine, a novel CK2α inhibitor, effectively suppressed GRP94 phosphorylation, LRP6 stabilization, and metastasis of TNBC. Our results point to the critical role of CK2α-mediated GRP94 phosphorylation in TNBC metastasis through activation of Wnt signaling, highlighting GRP94 as a therapeutic target to impede TNBC metastasis.

Galectins in epithelial-mesenchymal transition: roles and mechanisms contributing to tissue repair, fibrosis and cancer metastasis

Galectins are soluble glycan-binding proteins that interact with a wide range of glycoproteins and glycolipids and modulate a broad spectrum of physiological and pathological processes. The expression and subcellular localization of different galectins vary among tissues and cell types and change during processes of tissue repair, fibrosis and cancer where epithelial cells loss differentiation while acquiring migratory mesenchymal phenotypes. The epithelial-mesenchymal transition (EMT) that occurs in the context of these processes can include modifications of glycosylation patterns of glycolipids and glycoproteins affecting their interactions with galectins. Moreover, overexpression of certain galectins has been involved in the development and different outcomes of EMT. This review focuses on the roles and mechanisms of Galectin-1 (Gal-1), Gal-3, Gal-4, Gal-7 and Gal-8, which have been involved in physiologic and pathogenic EMT contexts.

HIF2α Promotes Cancer Metastasis through TCF7L2-Dependent Fatty Acid Synthesis in ccRCC

Recent studies have highlighted the notable involvement of the crosstalk between hypoxia-inducible factor 2 alpha (HIF2α) and Wnt signaling components in tumorigenesis. However, the cellular function and precise regulatory mechanisms of HIF2α and Wnt signaling interactions in clear cell renal cell carcinoma (ccRCC) remain elusive. To analyze the correlation between HIF2α and Wnt signaling, we utilized the Cancer Genome Atlas - Kidney Renal Clear Cell Carcinoma (TCGA-KIRC) public database, HIF2α RNA sequencing data, and conducted luciferase reporter assays. A Wnt-related gene set was employed to identify key regulators of Wnt signaling controlled by HIF2α in ccRCC. Furthermore, we assessed the biological effects of TCF7L2 on ccRCC metastasis and lipid metabolism in both in vivo and in vitro settings. Our outcomes confirm TCF7L2 as a key gene involved in HIF2α-mediated regulation of the canonical Wnt pathway. Functional studies demonstrate that TCF7L2 promotes metastasis in ccRCC. Mechanistic investigations reveal that HIF2α stabilizes TCF7L2 mRNA in a method based on m6A by transcriptionally regulating METTL3. Up-regulation of TCF7L2 enhances cellular fatty acid oxidation, which promotes histone acetylation. This facilitates the transcription of genes connected to epithelial-mesenchymal transition and ultimately enhances metastasis of ccRCC. These outcomes offer a novel understanding into the involvement of lipid metabolism in the signaling pathway regulation, offering valuable implications for targeted treatment in ccRCC.

Zinc finger proteins and ATP-binding cassette transporter-dependent multidrug resistance

BACKGROUND

Multidrug resistance (MDR) remains a significant challenge in cancer treatment, leading to poor clinical outcomes. Dysregulation of ATP-binding cassette (ABC) transporters has been identified as a key contributor to MDR. Zinc finger proteins (ZNPs) are key regulators of transcription and have emerged as potential contributors to cancer drug resistance. Bridging the knowledge gap between ZNPs and MDR is essential to understand a source of heterogeneity in cancer treatment. This review sought to elucidate how different ZNPs modulate the transcriptional regulation of ABC genes, contributing to resistance to cancer therapies.

METHODS

The search was conducted using PubMed, Google Scholar, EMBASE and Web of Science.

RESULTS

In addition to ABC-blockers, the transcriptional features regulated by ZNP are expected to play a role in reversing ABC-mediated MDR and predicting the efficacy of anticancer treatments. Among the ZNP-induced epithelial to mesenchymal transition, SNAIL, SLUG and Zebs have been identified as important factors in promoting MDR through activation of ATM, NFκB and PI3K/Akt pathways, exposing the metabolism to potential ZNP-MDR interactions. Additionally, nuclear receptors, such as VDR, ER and PXR have been found to modulate certain ABC regulations. Other C2H2-type zinc fingers, including Kruppel-like factors, Gli and Sp also have the potential to contribute to MDR.

CONCLUSION

Besides reviewing evidence on the effects of ZNP dysregulation on ABC-related chemoresistance in malignancies, significant markers of ZNP functions are discussed to highlight the clinical implications of gene-to-gene and microenvironment-to-gene interactions on MDR prospects. Future research on ZNP-derived biomarkers is crucial for addressing heterogeneity in cancer therapy.

Glycogen synthase kinase 3β: the nexus of chemoresistance, invasive capacity, and cancer stemness in pancreatic cancer

The treatment of pancreatic cancer remains a significant clinical challenge due to the limited number of patients eligible for curative (R0) surgery, failures in the clinical development of targeted and immune therapies, and the pervasive acquisition of chemotherapeutic resistance. Refractory pancreatic cancer is typified by high invasiveness and resistance to therapy, with both attributes related to tumor cell stemness. These malignant characteristics mutually enhance each other, leading to rapid cancer progression. Over the past two decades, numerous studies have produced evidence of the pivotal role of glycogen synthase kinase (GSK)3β in the progression of over 25 different cancer types, including pancreatic cancer. In this review, we synthesize the current knowledge on the pathological roles of aberrant GSK3β in supporting tumor cell proliferation and invasion, as well as its contribution to gemcitabine resistance in pancreatic cancer. Importantly, we discuss the central role of GSK3β as a molecular hub that mechanistically connects chemoresistance, tumor cell invasion, and stemness in pancreatic cancer. We also discuss the involvement of GSK3β in the formation of desmoplastic tumor stroma and in promoting anti-cancer immune evasion, both of which constitute major obstacles to successful cancer treatment. Overall, GSK3β has characteristics of a promising therapeutic target to overcome chemoresistance in pancreatic cancer.

Ferroptosis: Emerging mechanisms, biological function, and therapeutic potential in cancer and inflammation

Ferroptosis represents a distinct form of programmed cell death triggered by excessive iron accumulation and lipid peroxidation-induced damage. This mode of cell death differentiates from classical programmed cell death in terms of morphology and biochemistry. Ferroptosis stands out for its exceptional biological characteristics and has garnered extensive research and conversations as a form of programmed cell death. Its dysfunctional activation is closely linked to the onset of diseases, particularly inflammation and cancer, making ferroptosis a promising avenue for combating these conditions. As such, exploring ferroptosis may offer innovative approaches to treating cancer and inflammatory diseases. Our review provides insights into the relevant regulatory mechanisms of ferroptosis, examining the impact of ferroptosis-related factors from both physiological and pathological perspectives. Describing the crosstalk between ferroptosis and tumor- and inflammation-associated signaling pathways and the potential of ferroptosis inducers in overcoming drug-resistant cancers are discussed, aiming to inform further novel therapeutic directions for ferroptosis in relation to inflammatory and cancer diseases.

Nuclear isoform of RAPH1 interacts with FOXQ1 to promote aggressiveness and radioresistance in breast cancer

Radioresistance limits the efficacy of radiotherapy against breast cancer, especially the most lethal subtype of breast cancer, triple-negative breast cancer (TNBC). Epithelial-to-mesenchymal transition (EMT) is closely related to tumor radioresistance. In this work, we attempted to identify the key EMT-related transcription factor(s) that can induce radioresistance in breast cancer cells. A set of 44 EMT transcription factors were analyzed in parental and radioresistant TNBC cell lines. The function of FOXQ1, a differentially expressed transcription factor, was determined in TNBC radioresistance. FOXQ1-interacting proteins were identified by co-immunoprecipitation and mass spectrometry. Compared with parental cells, FOXQ1 was significantly upregulated in radioresistant TNBC cells. Silencing of FOXQ1 increased the radiosensitiviy of radioresistant TNBC cells both in vitro and in vivo. FOXQ1 associated with a nuclear isoform of RAPH1 (named RAPH1-i3) in radioresistant TNBC cells. Overexpression of RAPH1-i3 enhanced TNBC cell proliferation and migration, and most interestingly, induced radioresistance in parental TNBC cells when co-expressed with FOXQ1. Similar findings were observed in estrogen receptor-positive breast cancer cell lines that had co-expression of RAPH1-i3 and FOXQ1. Mechanistically, co-expression of RAPH1-i3 and FOXQ1 activated STAT3 signaling and increased the expression of CCND1, MCL1, Bcl-XL, and MMP2. Depletion of RAPH1-i3 impaired the radioresistance of radioresistant TNBC cells. Additionally, RAPH1-i3 upregulation was associated with advanced tumor stage and reduced disease-free survival in TNBC patients. These results collectively show that RAPH1-i3 interacts with FOXQ1 to promote breast cancer progression and radioresistance. RAPH1-i3 and FOXQ1 represent therapeutic targets for the treatment of breast cancer including TNBC.

Neurotransmitter Receptor HTR2B Regulates Lipid Metabolism to Inhibit Ferroptosis in Gastric Cancer

Nerves can support tumor development by secreting neurotransmitters that promote cancer cell proliferation and invasion. 5-Hydroxytryptamine (5-HT) is a critical neurotransmitter in the gastrointestinal nervous system, and 5-HT signaling has been shown to play a role in tumorigenesis. Here, we found that expression of the 5-HT receptor HTR2B was significantly elevated in human gastric adenocarcinoma tissues compared with nontumor tissues, and high HTR2B expression corresponded to shorter patient survival. Both 5-HT and a specific HTR2B agonist enhanced gastric adenocarcinoma cell viability under metabolic stress, reduced cellular and lipid reactive oxygen species, and suppressed ferroptosis; conversely, HTR2B loss or inhibition with a selective HTR2B antagonist yielded the inverse tumor suppressive effects. In a patient-derived xenograft tumor model, HTR2B-positive tumors displayed accelerated growth, which was inhibited by HTR2B antagonists. Single-cell analysis of human gastric adenocarcinoma tissues revealed enrichment of PI3K/Akt/mTOR and fatty acid metabolism-related gene clusters in cells expressing HTR2B compared with HTR2B-negative cells. Mechanistically, HTR2B cooperated with Fyn to directly regulate p85 activity and trigger the PI3K/Akt/mTOR signaling pathway, which led to increased expression of HIF1α and ABCD1 along with decreased levels of lipid peroxidation and ferroptosis. Together, these findings demonstrate that HTR2B activity modulates PI3K/Akt/mTOR signaling to stimulate gastric cancer cell survival and indicate that HTR2B expression could be a potential prognostic biomarker in patients with gastric cancer.

SIGNIFICANCE

Nerve cancer cross-talk mediated by HTR2B inhibits lipid peroxidation and ferroptosis in gastric cancer cells and promotes viability under metabolic stress, resulting in increased tumor growth and decreased patient survival.

Context-dependent TGFβ family signalling in cell fate regulation

The transforming growth factor-β (TGFβ) family are a large group of evolutionarily conserved cytokines whose signalling modulates cell fate decision-making across varying cellular contexts at different stages of life. Here we discuss new findings in early embryos that reveal how, in contrast to our original understanding of morphogen interpretation, robust cell fate specification can originate from a noisy combination of signalling inputs and a broad range of signalling levels. We compare this evidence with novel findings on the roles of TGFβ family signalling in tissue maintenance and homeostasis during juvenile and adult life, spanning the skeletal, haemopoietic and immune systems. From these comparisons, it emerges that in contrast to robust developing systems, relatively small perturbations in TGFβ family signalling have detrimental effects at later stages in life, leading to aberrant cell fate specification and disease, for example in cancer or congenital disorders. Finally, we highlight novel strategies to target and amend dysfunction in signalling and discuss how gleaning knowledge from different fields of biology can help in the development of therapeutics for aberrant TGFβ family signalling in disease.

Oxidative stress regulation and related metabolic pathways in epithelial-mesenchymal transition of breast cancer stem cells

Epithelial-mesenchymal transition (EMT) is a cell remodeling process in which epithelial cells undergo a reversible phenotype switch via the loss of adhesion capacity and acquisition of mesenchymal characteristics. In other words, EMT activation can increase invasiveness and metastatic properties, and prevent the sensitivity of tumor cells to chemotherapeutics, as mesenchymal cells have a higher resistance to chemotherapy and immunotherapy. EMT is orchestrated by a complex and multifactorial network, often linked to episodic, transient, or partial events. A variety of factors have been implicated in EMT development. Based on this concept, multiple metabolic pathways and master transcription factors, such as Snail, Twist, and ZEB, can drive the EMT. Emerging evidence suggests that oxidative stress plays a significant role in EMT induction. One emerging theory is that reducing mitochondrial-derived reactive oxygen species production may contribute to EMT development. This review describes how metabolic pathways and transcription factors are linked to EMT induction and addresses the involvement of signaling pathways.

Exosomal miR-331-3p derived from chemoresistant osteosarcoma cells induces chemoresistance through autophagy

BACKGROUND

Osteosarcoma is a common malignant bone tumor, and chemotherapy can effectively improve the prognosis. MicroRNA-331 (MiR-331) is associated with poor cancer outcomes. However, the role of miR-331 in osteosarcoma remains to be explored.

METHODS

Drug-resistant osteosarcoma cells were cultured, and their exosomes were purified. The secretion and uptake of exosomes by drug-resistant osteosarcoma and osteosarcoma cells were confirmed using a fluorescence tracking assay and Transwell experiments. The effects of drug-resistant exosomes on cell proliferation were determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. siRNA-Drosha and neutral sphingomyelinase inhibitor GW4869 were used to determine the transfer of miRNAs. qRT-PCR and western blotting were used to detect the role of autophagy in the regulation of drug-resistant cell-derived exosomal miR-331-3p.

RESULTS

Exosomal miR-331-3p levels in drug-resistant cells were higher than in exosomes from osteosarcoma cells. The exosomes secreted by the drug-resistant osteosarcoma cells could be absorbed by osteosarcoma cells, leading to acquired drug resistance in previously non-resistance cells. Inhibition of miRNAs resulted in reduced transmission of drug resistance transmission by exosomes. Exosomes from drug-resistant osteosarcoma cells transfected with siRNA-Drosha or treated by GW4869 could not enhance the proliferation of MG63 and HOS cells. Finally, miR-331-3p in the exosomes secreted by drug-resistant osteosarcoma cells could induce autophagy of osteosarcoma cells, allowing them to acquire drug resistance. The inhibition of miR-331-3p decreased drug resistance of osteosarcoma cells.

CONCLUSION

Exosomes secreted from chemoresistant osteosarcoma cells promote drug resistance through miR-331-3p and autophagy. Inhibition of miR-331-3p could be used to alleviate drug resistance in osteosarcoma.

Integrating bulk and single-cell RNA sequencing data reveals epithelial-mesenchymal transition molecular subtype and signature to predict prognosis, immunotherapy efficacy, and drug candidates in low-grade gliomas

Objective: Epithelial-mesenchymal transition (EMT) is a tightly regulated and dynamic process occurring in both embryonic development and tumor progression. Our study aimed to comprehensively explore the molecular subtypes, immune landscape, and prognostic signature based on EMT-related genes in low-grade gliomas (LGG) in order to facilitate treatment decision-making and drug discovery. Methods: We curated EMT-related genes and performed molecular subtyping with consensus clustering algorithm to determine EMT expression patterns in LGG. The infiltration level of diverse immune cell subsets was evaluated by implementing the single-sample gene set enrichment analysis (ssGSEA) and ESTIMATE algorithms. The distinctions in clinical characteristics, mutation landscape, and immune tumor microenvironment (TME) among the subtypes were subjected to further investigation. Gene Set Variation Analysis (GSVA) was performed to explore the biological pathways that were involved in subtypes. The chemo drug sensitivity and immunotherapy of subtypes were estimated through GDSC database and NTP algorithm. To detect EMT subtype-related prognostic gene modules, the analysis of weighted gene co-expression network (WGCNA) was performed. The LASSO algorithm was utilized to construct a prognostic risk model, and its efficacy was verified through an independent CGGA dataset. Finally, the expression of the hub genes from the prognostic model was evaluated through the single-cell dataset and in-vitro experiment. Results: The TCGA-LGG dataset revealed the creation of two molecular subtypes that presented different prognoses, clinical implications, TME, mutation landscapes, chemotherapy, and immunotherapy. A three-gene signature (SLC39A1, CTSA and CLIC1) based on EMT expression pattern were established through WGCNA analysis. Low-risk patients showed a positive outlook, increased immune cell presence, and higher expression of immune checkpoint proteins. In addition, several promising drugs, including birinapant, fluvastatin, clofarabine, dasatinib, tanespimycin, TAK-733, GDC-0152, AZD8330, trametinib and ingenol-mebutate had great potential to the treatment of high risk patients. Finally, CTSA and CLIC1 were highly expressed in monocyte cell through single-cell RNA sequencing analysis. Conclusion: Our research revealed non-negligible role of EMT in the TME diversity and complexity of LGG. A prognostic signature may contribute to the personalized treatment and prognostic determination.

TGF-β in correlation with tumor progression, immunosuppression and targeted therapy in colorectal cancer

Colorectal cancer (CRC) is a complex malignancy responsible for the second-highest cancer deaths worldwide. TGF-β maintains normal cellular homeostasis by inhibiting the cell cycle and inducing apoptosis, but its elevated level is correlated with colorectal cancer progression, as TGF-β is a master regulator of the epithelial-to-mesenchymal transition, a critical step of metastasis. Tumors, including CRC, use elevated TGF-β levels to avoid immune surveillance by modulating immune cell differentiation, proliferation, and effector function. Presently, the treatment of advanced CRC is mainly based on chemotherapy, with multiple adverse effects. Thus, there is a need to develop alternate tactics because CRC continue to be mostly resistant to the present therapeutic regimen. TGF-β blockade has emerged as a promising therapeutic target in cancer therapy. Blocking TGF-β with phytochemicals and other molecules, such as antisense oligonucleotides, monoclonal antibodies, and bifunctional traps, alone or in combination, may be a safer and more effective way to treat CRC. Furthermore, combination immunotherapy comprising TGF-β blockers and immune checkpoint inhibitors is gaining popularity because both molecules work synergistically to suppress the immune system. Here, we summarize the current understanding of TGF-β as a therapeutic target for managing CRC and its context-dependent tumor-promoting or tumor-suppressing nature.

Expression of dual-specificity phosphatases in TGFß1-induced EMT in SKOV3 cells

BACKGROUND

The study aims to profile the dual-specificity phosphatases (DUSP) expression in response to Transforming growth factor β1 (TGFβ1)-induced epithelial- mesenchymal transition (EMT) in ovarian adenocarcinoma cells.

METHODS

The ovarian adenocarcinoma cell line SKOV3 was used as a TGFβ1-induced EMT model. Cells were incubated with 5 ng/mL TGFβ1 to induce EMT. EMT was confirmed with real-time qPCR, western blot, and immunofluorescence analyses of various EMT markers. Western blot was used to analyze phospho- and total MAPK protein levels. Typical and atypical DUSPs mRNA expression profile was determined by real-time qPCR.

RESULTS

The epithelial marker E-cadherin expressions were decreased and mesenchymal EMT markers Snail and Slug expression levelswere increased after TGFβ1 induction. Phosphorylation of ERK1/2 and p38 MAPK were enhanced in response to TGFβ1 treatment. The expression of DUSP2, DUSP6, DUSP8, DUSP10, and DUSP13 were decreased while DUSP7, DUSP16, DUSP18, DUSP21, and DUSP27 were increased by TGFβ1.

DISCUSSION

TGFβ1 induced EMT which was accompanied by increased activity of MAPKs, and led to marked changes in expressions of several DUSPs in SKOV3 cells.

Ferroptosis: Promising approach for cancer and cancer immunotherapy

Ferroptosis is the cell death induced by ferrous ions and lipid peroxidation accumulation in tumor cells. Targeting ferroptosis, which is regulated by various metabolic and immune elements, might become a novel strategy for anti-tumor therapy. In this review, we will focus on the mechanism of ferroptosis and its interaction with cancer and tumor immune microenvironment, especially for the relationship between immune cells and ferroptosis. Also, we will discuss the latest preclinical progress of the collaboration between the ferroptosis-targeted drugs and immunotherapy, and the best potential conditions for their combined use. It will present a future insight on the possible value of ferroptosis in cancer immunotherapy.

Reshaping the Pancreatic Cancer Microenvironment at Different Stages with Chemotherapy

The dynamic tumor microenvironment, especially the immune microenvironment, during the natural progression and/or chemotherapy treatment is a critical frontier in understanding the effects of chemotherapy on pancreatic cancer. Non-stratified pancreatic cancer patients always receive chemotherapeutic strategies, including neoadjuvant chemotherapy and adjuvant chemotherapy, predominantly according to their physical conditions and different disease stages. An increasing number of studies demonstrate that the pancreatic cancer tumor microenvironment could be reshaped by chemotherapy, an outcome caused by immunogenic cell death, selection and/or education of preponderant tumor clones, adaptive gene mutations, and induction of cytokines/chemokines. These outcomes could in turn impact the efficacy of chemotherapy, making it range from synergetic to resistant and even tumor-promoting. Under chemotherapeutic impact, the metastatic micro-structures in the primary tumor may be built to leak tumor cells into the lymph or blood vasculature, and micro-metastatic/recurrent niches rich in immunosuppressive cells may be recruited by cytokines and chemokines, which provide housing conditions for these circling tumor cells. An in-depth understanding of how chemotherapy reshapes the tumor microenvironment may lead to new therapeutic strategies to block its adverse tumor-promoting effects and prolong survival. In this review, reshaped pancreatic cancer tumor microenvironments due to chemotherapy were reflected mainly in immune cells, pancreatic cancer cells, and cancer-associated fibroblast cells, quantitatively, functionally, and spatially. Additionally, small molecule kinases and immune checkpoints participating in this remodeling process caused by chemotherapy are suggested to be blocked reasonably to synergize with chemotherapy.

Light and electron microscopy continuum-resolution imaging of 3D cell cultures

3D cell cultures, in particular organoids, are emerging models in the investigation of healthy or diseased tissues. Understanding the complex cellular sociology in organoids requires integration of imaging modalities across spatial and temporal scales. We present a multi-scale imaging approach that traverses millimeter-scale live-cell light microscopy to nanometer-scale volume electron microscopy by performing 3D cell cultures in a single carrier that is amenable to all imaging steps. This allows for following organoids' growth, probing their morphology with fluorescent markers, identifying areas of interest, and analyzing their 3D ultrastructure. We demonstrate this workflow on mouse and human 3D cultures and use automated image segmentation to annotate and quantitatively analyze subcellular structures in patient-derived colorectal cancer organoids. Our analyses identify local organization of diffraction-limited cell junctions in compact and polarized epithelia. The continuum-resolution imaging pipeline is thus suited to fostering basic and translational organoid research by simultaneously exploiting the advantages of light and electron microscopy.

Lnc-ing epigenetic mechanisms with autophagy and cancer drug resistance

Long noncoding RNAs (lncRNAs) comprise a diverse class of RNA molecules that regulate various physiological processes and have been reported to be involved in several human pathologies ranging from neurodegenerative disease to cancer. Therapeutic resistance is a major hurdle for cancer treatment. Over the past decade, several studies has emerged on the role of lncRNAs in cancer drug resistance and many trials have been conducted employing them. LncRNAs also regulate different cell death pathways thereby maintaining a fine balance of cell survival and death. Autophagy is a complex cell-killing mechanism that has both cytoprotective and cytotoxic roles. Similarly, autophagy can lead to the induction of both chemosensitization and chemoresistance in cancer cells upon therapeutic intervention. Recently the role of lncRNAs in the regulation of autophagy has also surfaced. Thus, lncRNAs can be used in cancer therapeutics to alleviate the challenges of chemoresistance by targeting the autophagosomal axis. In this chapter, we discuss about the role of lncRNAs in autophagy-mediated cancer drug resistance and its implication in targeted cancer therapy.

Targeting mitochondria as a potential therapeutic strategy against chemoresistance in cancer

The importance of mitochondria is not only limited to energy generation but also in several physical and chemical processes critical for cell survival. Mitochondria play an essential role in cellular apoptosis, calcium ion transport and cellular metabolism. Mutation in the nuclear and mitochondrial genes, altered oncogenes/tumor suppressor genes, and deregulated signalling for cell viability are major reasons for cancer progression and chemoresistance. The development of drug resistance in cancer patients is a major challenge in cancer treatment as the resistant cells are often more aggressive. The drug resistant cells of numerous cancer types exhibit the deregulation of mitochondrial function. The increased biogenesis of mitochondria and its dynamic alteration contribute to developing resistance. Further, a small subpopulation of cancer stem cells in the heterogeneous tumor is primarily responsible for chemoresistance and has an attribute of mitochondrial dysfunction. This review highlights the critical role of mitochondrial dysfunction in chemoresistance in cancer cells through the processes of apoptosis, autophagy/mitophagy, and cancer stemness. Mitochondria-targeted therapeutic strategies might help reduce cancer progression and chemoresistance induced by various cancer drugs.

A cancer cell membrane coated, doxorubicin and microRNA co-encapsulated nanoplatform for colorectal cancer theranostics

Endogenous microRNAs (miRNA) in tumors are currently under exhaustive investigation as potential therapeutic agents for cancer treatment. Nevertheless, RNase degradation, inefficient and untargeted delivery, limited biological effect, and currently unclear side effects remain unsettled issues that frustrate clinical application. To address this, a versatile targeted delivery system for multiple therapeutic and diagnostic agents should be adapted for miRNA. In this study, we developed membrane-coated PLGA-b-PEG DC-chol nanoparticles (m-PPDCNPs) co-encapsulating doxorubicin (Dox) and miRNA-190-Cy7. Such a system showed low biotoxicity, high loading efficiency, and superior targeting ability. Systematic delivery of m-PPDCNPs in mouse models showed exceptionally specific tumor accumulation. Sustained release of miR-190 inhibited tumor angiogenesis, tumor growth, and migration by regulating a large group of angiogenic effectors. Moreover, m-PPDCNPs also enhanced the sensitivity of Dox by suppressing TGF-β signal in colorectal cancer cell lines and mouse models. Together, our results demonstrate a stimulating and promising m-PPDCNPs nanoplatform for colorectal cancer theranostics.

Tumour budding is a novel marker in breast cancer: the clinical application and future prospects

Breast cancer (BC) is a group of markedly heterogeneous tumours. There are many subtypes with different biological behaviours and clinicopathological characteristics, leading to significantly different prognosis. Despite significant advances in the treatment of BC, early metastatic is a critical factor for poor prognosis in BC patients. Tumour budding (TB) is considered as the first step process of tumour metastasis and is related to the epithelial-mesenchymal transition (EMT). TB has been observed in a variety of cancers, such as colorectal and gastric cancer, and had been considered as a distinct clinicopathological characteristics for early metastasis. However, TB evaluation standards and clinical application are not uniform in BC, as well as its molecular mechanism is not fully understood. Here, we reviewed the interpretation criteria, mechanism, clinicopathological characteristics and clinical application prospects of TB in BC. Key messagesCurrently, tumour budding is a poor prognosis for various solid tumours, also in breast cancer.Tumour budding is based on epithelial-mesenchymal transition and tumour microenvironment factors and is presumed to be an early step in the metastatic process.Breast cancer tumour budding still needs multi-centre experiments. We summarize the current research on breast cancer tumour budding, analyse the method of discriminating breast cancer tumour budding and explore the prognostic role and mechanism in breast cancer.

Combating Drug Resistance by Exploiting miRNA-200c-Controlled Phase II Detoxification

Acquired drug resistance constitutes a serious obstacle to the successful therapy of cancer. In the process of therapy resistance, microRNAs can play important roles. In order to combat resistance formation and to improve the efficacy of chemotherapeutics, the mechanisms of the multifaceted hsa-miR-200c on drug resistance were elucidated. Upon knockout of hsa-miR-200c in breast carcinoma cells, a proteomic approach identified altered expression of glutathione S-transferases (GSTs) when cells were treated with the chemotherapeutic drug doxorubicin. In different hsa-miR-200c expression systems, such as knockout, inducible sponge and inducible overexpression, the differential expression of all members of the GST family was evaluated. Expression of hsa-miR-200c in cancer cells led to the repression of a multitude of these GSTs and as consequence, enhanced drug-induced tumor cell death which was evaluated for two chemotherapeutic drugs. Additionally, the influence of hsa-miR-200c on the glutathione pathway, which is part of the phase II detoxification mechanism, was investigated. Finally, the long-term effects of hsa-miR-200c on drug efficacy were studied in vitro and in vivo. Upon doxycycline induction of hsa-miR-200c, MDA-MB 231 xenograft mouse models revealed a strongly reduced tumor growth and an enhanced treatment response to doxorubicin. A combined treatment of these tumors with hsa-miR-200c and doxorubicin resulted in complete regression of the tumor in 60% of the animals. These results identify hsa-miR-200c as an important player regulating the cellular phase II detoxification, thus sensitizing cancer cells not expressing this microRNA to chemotherapeutics and reversing drug resistance through suppression of GSTs.

Bidirectional crosstalk between epithelial-mesenchymal plasticity and IFNγ-induced PD-L1 expression promotes tumour progression

Epithelial-mesenchymal transition (EMT) and immunoevasion through upregulation of programmed death-ligand 1 (PD-L1) are important drivers of cancer progression. While EMT has been proposed to facilitate PD-L1-mediated immunosuppression, molecular mechanisms of their interaction remain obscure. Here, we provide insight into these mechanisms by proposing a mathematical model that describes the crosstalk between EMT and interferon gamma (IFNγ)-induced PD-L1 expression. Our model shows that via interaction with microRNA-200 (miR-200), the multi-stability of the EMT regulatory circuit is mirrored in PD-L1 levels, which are further amplified by IFNγ stimulation. This IFNγ-mediated effect is most prominent for cells in a fully mesenchymal state and less strong for those in an epithelial or partially mesenchymal state. In addition, bidirectional crosstalk between miR-200 and PD-L1 implies that IFNγ stimulation allows cells to undergo EMT for lower amounts of inducing signal, and the presence of IFNγ accelerates EMT and decelerates mesenchymal-epithelial transition (MET). Overall, our model agrees with published findings and provides insight into possible mechanisms behind EMT-mediated immune evasion, and primary, adaptive, or acquired resistance to immunotherapy. Our model can be used as a starting point to explore additional crosstalk mechanisms, as an improved understanding of these mechanisms is indispensable for developing better diagnostic and therapeutic options for cancer patients.

The small molecule chemical compound cinobufotalin attenuates resistance to DDP by inducing ENKUR expression to suppress MYH9-mediated c-Myc deubiquitination in lung adenocarcinoma

The small molecule chemical compound cinobufotalin (CB) is reported to be a potential antitumour drug that increases cisplatin (DDP) sensitivity in nasopharyngeal carcinoma. In this study, we first found that CB decreased DDP resistance, migration and invasion in lung adenocarcinoma (LUAD). Mechanistic studies showed that CB induced ENKUR expression by suppressing PI3K/AKT signalling to downregulate c-Jun, a negative transcription factor of ENKUR. Furthermore, ENKUR was shown to function as a tumour suppressor by binding to β-catenin to decrease c-Jun expression, thus suppressing MYH9 transcription. Interestingly, MYH9 is a binding protein of ENKUR. The Enkurin domain of ENKUR binds to MYH9, and the Myosin_tail of MYH9 binds to ENKUR. Downregulation of MYH9 reduced the recruitment of the deubiquitinase USP7, leading to increased c-Myc ubiquitination and degradation, decreased c-Myc nuclear translocation, and inactivation of epithelial-mesenchymal transition (EMT) signalling, thus attenuating DDP resistance. Our data demonstrated that CB is a promising antitumour drug and may be a candidate chemotherapeutic drug for LUAD patients.

Functions and underlying mechanisms of lncRNA HOTAIR in cancer chemotherapy resistance

Chemotherapy has been one of the most important treatments for advanced cancer in recent decades. Although the sensitivity rate of initial chemotherapy is high, patients with chemotherapy resistant tumors, experience tumor recurrence. In recent years, many studies have shown that homeobox transcript antisense intergenic RNA (HOTAIR) is involved in many pathological processes including carcinogenesis. The abnormal regulation of a variety of cell functions by HOTAIR, such as apoptosis, the cell cycle, epithelial-mesenchymal transition, autophagy, self-renewal, and metabolism, is associated with chemotherapy resistance. Therefore, there is an urgent need to understand the biology and mechanism underlying the role of HOTAIR in tumor behavior and its potential as a biomarker for predicting the effect of chemotherapy. In this manuscript, we review the mechanisms underlying HOTAIR-related drug resistance and discuss the limitations of current knowledge and propose potential future directions.

Conjugated Linoleic Acid Treatment Attenuates Cancerous features in Hepatocellular Carcinoma Cells

BACKGROUND

A growing number of hepatocellular carcinoma (HCC), and recurrence frequency recently have drawn researchers' attention to alternative approaches. The concept of differentiation therapies (DT) relies on inducing differentiation in HCC cells in order to inhibit recurrence and metastasis. Hepatocyte nuclear factor 4 alpha (HNF4α) is the key hepatogenesis transcription factor and its upregulation may decrease the invasiveness of cancerous cells by suppressing epithelial-mesenchymal transition (EMT). This study aimed to evaluate the effect of conjugated linoleic acid (CLA) treatment, natural ligand of HNF4α, on the proliferation, migration, and invasion capacities of HCC cells in vitro. Materials and Method. Sk-Hep-1 and Hep-3B cells were treated with different doses of CLA or BIM5078 [1-(2'-chloro-5'-nitrobenzenesulfonyl)-2-methylbenzimidazole], an HNF4α antagonist. The expression levels of HNF4a and EMT related genes were evaluated and associated to hepatocytic functionalities, migration, and colony formation capacities, as well as to viability and proliferation rate of HCC cells.

RESULTS

In both HCC lines, CLA treatment induced HNF4α expression in parallel to significantly decreased EMT marker levels, migration, colony formation capacity, and proliferation rate, whereas BIM5078 treatment resulted in the opposite effects. Moreover, CLA supplementation also upregulated ALB, ZO1, and HNF4α proteins as well as glycogen storage capacity in the treated HCC cells.

CONCLUSION

CLA treatment can induce a remarkable hepatocytic differentiation in HCC cells and attenuates cancerous features. This could be as a result of HNF4a induction and EMT inhibition.

Upregulation of dual-specificity phosphatase-26 is required for transforming growth factor β1(TGFβ1)-induced Epithelial-mesenchymal transition in A549 and PANC1 cells

BACKGROUND

Transforming Growth Factor β (TGFβ) proteins are potent inducers of the epithelial-mesenchymal transition (EMT) in tumor cells. Although mitogen-activated protein kinase (MAPK) family has been shown to be involved in TGFβ-induced EMT, role of Dual Specificity Phosphatases (DUSP), key regulators of MAPK activity, in TGFβ-induced EMT is largely unkonwn.

METHODS AND RESULTS

Real-time qPCR analyses were performed to determine the effect of TGFβ1 on expression of EMT genes and DUSP proteins in the non-small cell lung cancer model A549 and pancreatic adenocarcinoma model PANC1 cells. Western blot analyses were conducted to study the changes in protein levels of EMT proteins and select DUSP proteins, as well as phosphorylations of MAPK proteins upon TGFβ1 stimulation. Small interfering RNA (siRNA) was utilized to reduce expressions of DUSP genes. We observed that the EMT phenotype coincided with increases in phosphorylations of the MAPK proteins ERK1/2, p38MAPK, and JNK upon TGFβ1 stimulation. Real-time qPCR analysis showed increases in DUSP15 and DUSP26 mRNA levels and Western blot analysis confirmed the increase in DUSP26 protein levels in both A549 and PANC1 cells treated with TGFβ1 relative to control. Silencing of DUSP26 expression by siRNA markedly suppressed the effect of TGFβ1 on E-cadherin and mesenchymal genes in the cells.

CONCLUSIONS

Data provided suggest that TGFβ1 modulates the expression of DUSP genes and that upregulation of DUSP26 may be required for TGFβ1-promoted EMT in A549 and PANC1 cells. Further studies should be carried out to elucidate the requirement of individual DUSPs in TGFβ1-associated EMT in tumor cells.

EGR1-CCL2 Feedback Loop Maintains Epithelial-Mesenchymal Transition of Cisplatin-Resistant Gastric Cancer Cells and Promotes Tumor Angiogenesis

BACKGROUND

The mechanism of cisplatin resistance in gastric cancer (GC) is still elusive; several recent evidences proposed that chemoresistant tumor cells acquired aggressive behaviors.

AIMS

This study was aimed to investigate the mechanism of epithelial-mesenchymal transition (EMT) and angiogenesis in chemoresistant GC.

METHODS

Bioinformatics analysis and function or mechanism experiments including RT-qPCR, immunofluorescence, Western blot, luciferase reporter assay, Chromatin immunoprecipitation, Chicken chorioallantoic membrane assay and animal experiments were applied to evaluate the role of EGR1-CCL2 feedback loop.

RESULTS

Compared with the parental cell line SGC7901, cisplatin resistant SGC7901R cells underwent EMT and showed increased angiogenic capabilities. Mechanistically, SGC7901R cells showed increased levels of EGR1, which could transcriptionally activate the angiogenic factor CCL2 and EMT regulator ZEB2. Reciprocally, CCL2 activated the CCR2-ERK-ELK1-EGR1 pathway, thus forming a positive feed-forward loop. Moreover, CCL2 in culture medium of SGC7901R cells promoted angiogenesis of Human Umbilical Vein Endothelial Cells (HUVECs). EGR1 expression was positively correlated with CCL2 and ZEB2 in clinical GC tissues, and the depletion of ERG1 could also decrease microvessel density and ZEB2 expression in metastatic nodules of nude mice.

CONCLUSIONS

EGR1-CCL2 feedback loop might exert critical roles on EMT and angiogenesis of chemoresistant GC.

Epithelial-Mesenchymal Transition-Mediated Tumor Therapeutic Resistance

Cancer is one of the world’s most burdensome diseases, with increasing prevalence and a high mortality rate threat. Tumor recurrence and metastasis due to treatment resistance are two of the primary reasons that cancers have been so difficult to treat. The epithelial–mesenchymal transition (EMT) is essential for tumor drug resistance. EMT causes tumor cells to produce mesenchymal stem cells and quickly adapt to various injuries, showing a treatment-resistant phenotype. In addition, multiple signaling pathways and regulatory mechanisms are involved in the EMT, resulting in resistance to treatment and hard eradication of the tumors. The purpose of this study is to review the link between EMT, therapeutic resistance, and the molecular process, and to offer a theoretical framework for EMT-based tumor-sensitization therapy.

Snail acetylation by autophagy-derived acetyl-coenzyme A promotes invasion and metastasis of KRAS-LKB1 co-mutated lung cancer cells

Background

Autophagy is elevated in metastatic tumors and is often associated with active epithelial‐to‐mesenchymal transition (EMT). However, the extent to which EMT is dependent on autophagy is largely unknown. This study aimed to identify the mechanisms by which autophagy facilitates EMT.

Methods

We employed a liquid chromatography‐based metabolomic approach with kirsten rat sarcoma viral oncogene (KRAS) and liver kinase B1 (LKB1) gene co‐mutated (KL) cells that represent an autophagy/EMT‐coactivated invasive lung cancer subtype for the identification of metabolites linked to autophagy‐driven EMT activation. Molecular mechanisms of autophagy‐driven EMT activation were further investigated by quantitative real‐time polymerase chain reaction (qRT‐PCR), Western blotting analysis, immunoprecipitation, immunofluorescence staining, and metabolite assays. The effects of chemical and genetic perturbations on autophagic flux were assessed by two orthogonal approaches: microtubule‐associated protein 1A/1B‐light chain 3 (LC3) turnover analysis by Western blotting and monomeric red fluorescent protein‐green fluorescent protein (mRFP‐GFP)‐LC3 tandem fluorescent protein quenching assay. Transcription factor EB (TFEB) activity was measured by coordinated lysosomal expression and regulation (CLEAR) motif‐driven luciferase reporter assay. Experimental metastasis (tail vein injection) mouse models were used to evaluate the impact of calcium/calmodulin‐dependent protein kinase kinase 2 (CAMKK2) or ATP citrate lyase (ACLY) inhibitors on lung metastasis using IVIS luciferase imaging system.

Results

We found that autophagy in KL cancer cells increased acetyl‐coenzyme A (acetyl‐CoA), which facilitated the acetylation and stabilization of the EMT‐inducing transcription factor Snail. The autophagy/acetyl‐CoA/acetyl‐Snail axis was further validated in tumor tissues and in autophagy‐activated pancreatic cancer cells. TFEB acetylation in KL cancer cells sustained pro‐metastatic autophagy in a mammalian target of rapamycin complex 1 (mTORC1)‐independent manner. Pharmacological inhibition of this axis via CAMKK2 inhibitors or ACLY inhibitors consistently reduced the metastatic capacity of KL cancer cells in vivo.

Conclusions

This study demonstrates that autophagy‐derived acetyl‐CoA promotes Snail acetylation and thereby facilitates invasion and metastasis of KRAS‐LKB1 co‐mutated lung cancer cells and that inhibition of the autophagy/acetyl‐CoA/acetyl‐Snail axis using CAMKK2 or ACLY inhibitors could be a potential therapeutic strategy to suppress metastasis of KL lung cancer.

Could inhibition of metalloproteinases be used to block the process of metastasis?

Metastasis is a multisequential process that allows tumor cells to migrate to tissues distant from the primary tumor. Only a small number of cells escape from the primary tumor; however, the metastases generated are responsible for more than 90% of cancer deaths. Many metastatic processes initially require the total or partial start‐up of a program for the transformation of tumor epithelial cells into mesenchymal cells (EMT). The launching of the EMT program is stimulated by cytokines and other elements produced by the diverse types of cells composing the tumor stroma. In parallel, a process of destabilization of the extracellular matrix (ECM) takes place by means of the synthesis of proteases of the matrix metalloproteinases (MMPs) family. EMC degradation allows the exportation of some tumor cells as mesenchymal cells to the circulatory system and their subsequent implantation in a tissue distant from the primary tumor. The blocking of these both processes appears as a hypothetical stop point in the metastatic mechanism. The present review deals with the different options to achieve the inhibition of MMPs, focusing on MMP7 as a target given its involvement in the metastatic processes of a wide variety of tumors.

The simultaneous implantation of the epithelial–mesenchymal program and the synthesis and activation of matrix metalloproteinases during the first phases of the metastasis process is known. The inhibition of proteases could constitute a possible blockage of the process. The review describes the evolution of the different inhibition mechanisms that could inform applicable therapeutic mechanisms for the paralysis of the metastatic process.

Effective suppression of triple negative breast cancer by paclitaxel nanoparticles conjugated with transmembrane TNF-α monoclonal antibody

Transmembrane TNF-α (tmTNF), a transmembrane form of TNF-α, was reported overexpressed in approximately 84% of triple-negative breast cancer (TNBC) patients and has emerged as a valid candidate biomarker for targeting TNBC. Paclitaxel is a first-line chemotherapeutic agent for the treatment of triple-negative breast cancer, but suffers from low water solubility, resulting in its low bioavailability. To achieve site-specific delivery of the anticancer chemotherapeutic drug (paclitaxel) on TNBC, we developed tmTNF-α monoclonal antibody (mAb)-conjugated paclitaxel (PTX) nanoparticles (NPs) (tmTNF-α mAb-PTX NPs) as potential nanocarriers. This targeted delivery-therapy nanocarriers was conducted by using an emulsification-evaporation method. tmTNF-α mAb-PTX NPs displayed favorable physicochemical properties. Compared with the control groups, tumor growth in human MDA-MB-231 xenograft mice was suppressed significantly by tmTNF-α mAb-PTX NPs. TmTNF-α mAb-PTX NPs exerts anti-tumor effects via promoting apoptosis and regulating mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K) / protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) cascade, as well as AMP-activated protein kinase (AMPK) and nuclear factor Kappa-B (NF-κB) pathways. Moreover, tmTNF-α mAb-PTX NPs can inhibit the process of epithelial-mesenchymal transition (EMT) in TNBC to suppress tumor progression and metastasis. Together, the novel tmTNF-α mAb-PTX NPs based targeted drug delivery system is a potentially highly effective approach for treating TNBC.

A novel NCI-H69V small cell lung cancer functional mini-tumor model for future treatment screening applications

Small cell lung cancer (SCLC) is aggressive and despite multiple clinical trials, its standard of care is unchanged for the past three decades. In vitro cancer models are crucial in chemotherapy development, and three-dimensional (3D) models aim to bridge the gap between two-dimensional (2D) flat cultures and in vivo testing. Functional 3D spheroids can better represent the in vivo situation and tumor characteristics than 2D models. An NCI-H69V SCLC mini-tumor model was developed in a clinostat-based rotating bioreactor system. Spheroid growth and viability were characterized for 30 days, and the ideal experimental window with mature and metabolically stable spheroids was determined. Application of the model for anticancer treatment screening was validated with the standard chemotherapeutic drug irinotecan, for an exposure period of 72 h. The following parameters were measured: soluble protein content, planar surface area measurements, intracellular adenosine triphosphate and extracellular adenylate kinase levels, and glucose consumption. Histological morphology of the spheroids was observed. The established model proved viable and stable, while treatment with irinotecan caused a decrease in cell growth, viability, and glucose consumption demonstrating reactivity of the model to chemotherapy. Therefore, this NCI-H69V SCLC functional spheroid model could be used for future anticancer compound screening.

Agmatinase facilitates the tumorigenesis of pancreatic adenocarcinoma through the TGFβ/Smad pathway

Pancreatic adenocarcinoma (PAAD) is one of the most lethal malignancies. Due to the lack of typical symptoms and difficulties in early diagnosis, PAAD has a high mortality rate. Therefore, it is essential to identify novel specific biomarkers for the application of targeted therapies. A previous study suggested that agmatinase (AGMAT) may fulfill important roles in tumor progression; however, these roles and the underlying mechanisms of AGMAT involvement in PAAD have yet to be thoroughly investigated. To address this shortcoming, in the present study the expression and prognostic significance of AGMAT were analyzed via several bioinformatics databases. Gain- and loss-of-function experiments were subsequently performed to observe the impact of AGMAT on the proliferation and metastasis of PAAD cells via Cell Counting Kit 8 (CCK-8) assay, colony formation assay, and cell migration and invasion assays in vitro. In order to probe the mechanisms involved, western blot assays were performed. AGMAT was found to be overexpressed in PAAD, and it was positively associated with a poor prognosis. Stable overexpression of AGMAT was found to lead to a marked increase in cell proliferation and metastasis through activation of the transforming growth factor-β (TGFβ)/Smad pathway, and via enhancing epithelial-mesenchymal transition (EMT). In conclusion, the results of the present study suggest that AGMAT may be an oncogene, and a pivotal mechanism has been uncovered in which AGMAT facilitates the progression of PAAD tumorigenesis through the TGFβ/Smad pathway.

Identification of EMT-Related Genes and Prognostic Signature With Significant Implications on Biological Properties and Oncology Treatment of Lower Grade Gliomas

The epithelial-mesenchymal transition (EMT) is an important process that drives progression, metastasis, and oncology treatment resistance in cancers. Also, the adjacent non-tumor tissue may affect the biological properties of cancers and have potential prognostic implications. Our study aimed to identify EMT-related genes in LGG samples, explore their impact on the biological properties of lower grade gliomas (LGG) through the multi-omics analysis, and reveal the potential mechanism by which adjacent non-tumor tissue participated in the malignant progression of LGG. Based on the 121 differentially expressed EMT-related genes between normal samples from the GTEx database and LGG samples in the TCGA cohort, we identified two subtypes and constructed EMTsig. Because of the genetic, epigenetic, and transcriptomic heterogeneity, malignant features including clinical traits, molecular traits, metabolism, anti-tumor immunity, and stemness features were different between samples with C1 and C2. In addition, EMTsig could also quantify the EMT levels, variation in prognosis, and oncology treatment sensitivity of LGG patients. Therefore, EMTsig could assist us in developing objective diagnostic tools and in optimizing therapeutic strategies for LGG patients. Notably, with the GSVA, we found that adjacent non-tumor tissue might participate in the progression, metastasis, and formation of the tumor microenvironment in LGG. Therefore, the potential prognostic implications of adjacent non-tumor tissue should be considered when performing clinical interventions for LGG patients. Overall, our study investigated and validated the effects of EMT-related genes on the biological properties from multiple perspectives, and provided new insights into the function of adjacent non-tumor tissue in the malignant progression of LGG.

Metabolomics and EMT Markers of Breast Cancer: A Crosstalk and Future Perspective

Cancer cells undergo transient EMT and MET phenomena or vice versa, along with the parallel interplay of various markers, often correlated as the determining factor in decoding metabolic profiling of breast cancers. Moreover, various cancer signaling pathways and metabolic changes occurring in breast cancer cells modulate the expression of such markers to varying extents. The existing research completed so far considers the expression of such markers as determinants regulating the invasiveness and survival of breast cancer cells. Therefore, this manuscript is crosstalk among the expression levels of such markers and their correlation in regulating the aggressiveness and invasiveness of breast cancer. We also attempted to cover the possible EMT-based metabolic targets to retard migration and invasion of breast cancer.

Gli1 promotes epithelial–mesenchymal transition and metastasis of non-small cell lung carcinoma by regulating Snail transcriptional activity and stability

Metastasis is crucial for the mortality of non-small cell lung carcinoma (NSCLC) patients. The epithelial–mesenchymal transition (EMT) plays a critical role in regulating tumor metastasis. Glioma-associated oncogene 1 (Gli1) is aberrantly active in a series of tumor tissues. However, the molecular regulatory relationships between Gli1 and NSCLC metastasis have not yet been identified. Herein, we reported Gli1 promoted NSCLC metastasis. High Gli1 expression was associated with poor survival of NSCLC patients. Ectopic expression of Gli1 in low metastatic A549 and NCI-H460 cells enhanced their migration, invasion abilities and facilitated EMT process, whereas knock-down of Gli1 in high metastatic NCI-H1299 and NCI-H1703 cells showed an opposite effect. Notably, Gli1 overexpression accelerated the lung and liver metastasis of NSCLC in the intravenously injected metastasis model. Further research showed that Gli1 positively regulated Snail expression by binding to its promoter and enhancing its protein stability, thereby facilitating the migration, invasion and EMT of NSCLC. In addition, administration of GANT-61, a Gli1 inhibitor, obviously suppressed the metastasis of NSCLC. Collectively, our study reveals that Gli1 is a critical regulator for NSCLC metastasis and suggests that targeting Gli1 is a prospective therapy strategy for metastatic NSCLC.

OVOL1 inhibits breast cancer cell invasion by enhancing the degradation of TGF-β type I receptor

Ovo-like transcriptional repressor 1 (OVOL1) is a key mediator of epithelial lineage determination and mesenchymal-epithelial transition (MET). The cytokines transforming growth factor-β (TGF-β) and bone morphogenetic proteins (BMP) control the epithelial-mesenchymal plasticity (EMP) of cancer cells, but whether this occurs through interplay with OVOL1 is not known. Here, we show that OVOL1 is inversely correlated with the epithelial-mesenchymal transition (EMT) signature, and is an indicator of a favorable prognosis for breast cancer patients. OVOL1 suppresses EMT, migration, extravasation, and early metastatic events of breast cancer cells. Importantly, BMP strongly promotes the expression of OVOL1, which enhances BMP signaling in turn. This positive feedback loop is established through the inhibition of TGF-β receptor signaling by OVOL1. Mechanistically, OVOL1 interacts with and prevents the ubiquitination and degradation of SMAD family member 7 (SMAD7), which is a negative regulator of TGF-β type I receptor stability. Moreover, a small-molecule compound 6-formylindolo(3,2-b)carbazole (FICZ) was identified to activate OVOL1 expression and thereby antagonizing (at least in part) TGF-β-mediated EMT and migration in breast cancer cells. Our results uncover a novel mechanism by which OVOL1 attenuates TGF-β/SMAD signaling and maintains the epithelial identity of breast cancer cells.

Long non-coding RNA HNF1A-AS1 induces 5-FU resistance of gastric cancer through miR-30b-5p/EIF5A2 pathway

BACKGROUND

Gastric cancer (GC) is one of the leading causes of cancer-related deaths worldwide and chemoresistance is a major cause for its poor prognosis. Long non-coding RNAs (lncRNAs) are associated with cancer chemoresistance. The current study sought to explore the mechanism of lncRNA HNF1A antisense RNA 1 (HNF1A-AS1) in mediating 5-fluorouracil (5-FU) resistance of GC.

METHODS

qRT-PCR was performed to detect the expression level of HNF1A-AS1 in GC tissues and cells. Abnormal expression of HNF1A-AS1 in GC cells was induced by lentivirus infection. Protein levels of EIF5A2, E-Cadherin, Vimentin and N-Cadherin were detected using western blot. Competitive endogenous RNA (ceRNA) mechanisms were explored through luciferase assays and RNA immunoprecipitation (RIP) assays. Functional experiments of chemoresistance were performed by CCK-8 assays, colony formation assays and flow cytometry with the treatment of 5-FU. Mouse tumor xenograft assays were performed to verify the findings in vivo.

RESULTS

The findings showed HNF1A-AS1 was significantly upregulated in GC tissues especially in chemoresistance group. Findings from in vitro and in vivo experiments showed HNF1A-AS1 increased cell viability and proliferation, repressed apoptosis and promoted xenograft tumors growth in the presence of 5-FU. Mechanistic studies revealed HNF1A-AS1 promoted chemoresistance by facilitating epithelial mesenchymal transition (EMT) process through upregulating EIF5A2 expression and HNF1A-AS1 acted as a sponge of miR-30b-5p.

CONCLUSIONS

The findings from the current study showed HNF1A-AS1 promoted 5-FU resistance by acting as a ceRNA of miR-30b-5p and promoting EIF5A2-induced EMT process in GC. This indicates that HNF1A-AS1 is a potential therapeutic target for alleviating GC chemoresistance.

The Emerging role of EMT-related lncRNAs in therapy resistance and their application as biomarkers

Cancer is the world's second largest cause of death. The most common cancer treatments are surgery, radiation therapy, and chemotherapy. Drug resistance, epithelial-to-mesenchymal transition (EMT), and metastasis are all pressing issues in cancer therapy today. Increasing evidence showed that drug-resistant and EMT are co-related with each other. Indeed, drug-resistant cancer cells possess enhanced EMT and invasive ability. Recent researches have demonstrated lncRNAs (long noncoding RNAs) are noncoding transcripts, which play an important role in the regulation of EMT, metastasis, and drug resistance in different cancers. However, the relationships among lncRNAs, EMT, and drug resistance are still unclear. These effects could be exerted via several signaling pathways such as TGF-β, PI3K-AKT, and Wnt/β-catenin. Identifying the crucial regulatory roles of lncRNAs in these pathways and processes leads to the development of novel targeted therapies. We review the key aspects of lncRNAs associated with EMT and therapy resistance. We focus on the crosstalk between lncRNAs and molecular signaling pathways affecting EMT and drug resistance. Moreover, each of the mentioned lncRNAs could be used as a potential diagnostic, prognostic, and therapeutic biomarker for cancer. Although, there are still many challenges to investigate lncRNAs for clinical applications.