Epithelial to Mesenchymal Transition History: From Embryonic Development to Cancers

Granzyme B Promotes Proliferation, Migration and EMT Process in Gastric Cancer

Granzyme B (GZMB), a critical member of the Gr gene family, is known to play an essential role in diverse physiological and pathological processes such as inflammation, acute and chronic inflammatory diseases, and cancer progression. In this study, we delve deeper into the role of GZMB within the context of gastric cancer (GC) to examine its expression patterns and functional implications. To accomplish this, we applied a combination of quantitative real-time polymerase chain reaction, western blotting, and immunohistochemistry techniques. These methodologies allowed us to accurately gauge GZMB expression levels in GC tissues and investigate their correlation with various clinical-pathological variables. Our secondary focus was to discern the regulatory influence of GZMB on GC cell biology. We used an array of assays including cell counting kit-8 (CCK-8), colony formation, 5-ethynyl-2'-deoxyuridine, and migration assays. The effect of GZMB on gastric cancer progression was further validated through a subcutaneous xenograft mouse model. Our findings underscored that GZMB mRNA and protein levels were upregulated in GC tissues, a feature that showed a significant correlation with GC staging. We also discovered that a decrease in GZMB expression via knockdown experiments suppressed the proliferation and migration capabilities of GC cells. This effect was manifested through diminished expression levels of epithelial-mesenchymal transition (EMT) markers. In stark contrast, the overexpression of GZMB through plasmid transfection appeared to enhance the proliferation and migration abilities of GC cells. This was coupled with an upregulation in EMT expression. Our study concludes by emphasizing that GZMB promotes the growth, migration, and EMT processes in gastric cancer. In vitro, cell-based experiments and in vivo xenograft mouse models confirm this. Our findings provide a more comprehensive understanding of GZMB's role in gastric cancer pathogenesis, potentially opening doors for novel therapeutic strategies targeting this molecular pathway.

Plasticity and resistance of cancer stem cells as a challenge for innovative anticancer therapies - do we know enough to overcome this?

According to the CSC hypothesis, cancer stem cells are pivotal in initiating, developing, and causing cancer recurrence. Since the identification of CSCs in leukemia, breast cancer, glioblastoma, and colorectal cancer in the 1990s, researchers have actively investigated the origin and biology of CSCs. However, the CSC hypothesis and the role of these cells in tumor development model is still in debate. These cells exhibit distinct surface markers, are capable of self-renewal, demonstrate unrestricted proliferation, and display metabolic adaptation. CSC phenotypic plasticity and the capacity to EMT is strictly connected to the stemness state. CSCs show high resistance to chemotherapy, radiotherapy, and immunotherapy. The plasticity of CSCs is significantly influenced by tumor microenvironment factors, such as hypoxia. Targeting the genetic and epigenetic changes of cancer cells, together with interactions with the tumor microenvironment, presents promising avenues for therapeutic strategies. See also the Graphical abstract(Fig. 1).

SQSTM1/p62 promotes the progression of gastric cancer through epithelial-mesenchymal transition

Background

SQSTM1/p62 is an autophagy-related receptor protein that participates in regulating tumorigenesis and multiple signaling pathways. Gastric cancer (GC) is a common tumor in the digestive tract and continues to pose a significant threat to human health. Therefore, this study aims to investigate the impact of p62 on gastric cancer.

Methods

Immunohistochemistry and Western blotting were employed to assess the expression level of the p62 protein in gastric cancer tissues and its correlation with prognosis. Subsequently, in vitro cell experiments were conducted to determine the role of p62 in gastric cancer cell proliferation, migration, and metastasis.

Result

The expression of p62 in gastric cancer tissues was significantly higher than in normal tissues. The expression of p62 was positively correlated with poor prognosis in gastric cancer patients. In vitro cell experiments indicated that p62 promotes gastric cancer cell proliferation and migration. Mechanistically, elevated p62 expression induced epithelial-mesenchymal transition (EMT), leading to upregulation of E-cadherin and downregulation of N-cadherin and vimentin.

Conclusion

This study provides novel and robust evidence for the mechanism by which elevated p62 expression promotes the progression of gastric cancer. It offers promising therapeutic targets for anti-tumor treatment strategies in gastric cancer patients.

GK921, a transglutaminase inhibitor, strengthens the antitumor effect of cisplatin on pancreatic cancer cells by inhibiting epithelial-to-mesenchymal transition

Pancreatic adenocarcinoma (PAAD), a common digestive malignant tumor, presents high mortality rates and limited treatment methods. Currently, chemotherapy remains the main therapy method for patients with PAAD. As a classical chemotherapy drug, cisplatin (DDP) is limited by dose-related toxicity in patients with PAAD. In this study, we demonstrated that TGM2 may be a treatment and prognosis marker in pancreatic cancer patients. Co-treatment of low dose of DDP and GK921, a transglutaminase (TGM2) inhibitor, is capable of synergistically inhibiting the PAAD cell viability and proliferation in vitro and in vivo. Based on in vitro study, GK921 inhibited the epithelial-to-mesenchymal transition (EMT) induced by TGM2 as well as aggravated cell cycle arrest and apoptosis resulted from DDP, making pancreatic cancer cells more sensible to DDP. Our results showed that GK921 increased the protein levels regarding E-cadherin as well as decreased the protein level regarding Snail2, N-cadherin, which indicated that GK921 inhibited EMT in pancreatic cancer cells. Snail2 overexpression inhibited GK921/DDP-induced cell apoptosis, as well as mitigated the GK921/DDP-caused cell death and the EMT inhibition. In vivo studies also found GK921/DDP combination can further inhibit the growth of PAAD without significantly side effects. To sum up, we showed that GK921 increased PAAD cells sensitivity to DDP via inhibiting EMT. As revealed, DDP/GK921 co-treatment could promisingly serve for treating PAAD patients.

p38 Mitogen-Activated Protein Kinase Inhibition of Mesenchymal Transdifferentiated Tumor Cells in Head and Neck Squamous Cell Carcinoma

High mortality in head and neck squamous cell carcinoma (HNSCC) is due to recurrence, metastasis, and radiochemotherapy (RCT) resistance. These phenomena are related to the tumor cell subpopulation undergoing partial epithelial to mesenchymal transition (pEMT). Repeated transforming growth factor-beta (TGF-beta-1) treatment via the p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway induces pEMT in SCC-25 HNSCC cells, and activates and stabilizes the pro-EMT transcription factor Slug. We investigated the growth inhibitory, cisplatin-sensitizing, and pro-apoptotic effects of p38 MAPK inhibition in cisplatin-resistant (SCC-25) and -sensitive (UPCI-SCC090) HNSCC cell lines, using two specific p38 MAPK inhibitors, SB202190 and ralimetinib. Cell viability was measured by MTT assay; cell cycle distribution and cell death were evaluated by flow cytometry; p38 MAPK phosphorylation, Slug protein stabilization, and p38 MAPK downstream targets were investigated by Western blot. p-p38 inhibitors achieved sustained phosphorylation of p38 MAPK (Thr180/Tyr182) and inhibition of its function, which resulted in decreased phosphorylation (Thr69/71) of the downstream target pATF2 in pEMT cells. Subsequently, the p-p38 inhibition resulted in reduced Slug protein levels. In accordance, p-p38 inhibition led to sensitization of pEMT cells to cisplatin-induced cell death; moreover, p-p38 inhibitor treatment cycles significantly decreased the viability of cisplatin-surviving cells. In conclusion, clinically relevant p38 inhibitors might be effective for RCT-resistant pEMT cells in HNSCC patients.

Exploring the role of miRNAs in early chicken embryonic development and their significance

In the early stages of embryonic development, a precise and strictly controlled hierarchy of gene expression is essential to ensure proper development of all cell types and organs. To better understand this gene control process, we constructed a small RNA library from 1- to 5-day-old chick embryos, and identified 2,459 miRNAs including 827 existing, 695 known, and 937 novel miRNAs with bioinformatic analysis. There was absolute high expression of a number of miRNAs in each stage, including gga-miR-363-3p (Em1d), gga-miR-26a-5p (Em2d and Em3d), gga-miR-10a-5p (Em4d), and gga-miR-199-5p (Em5d). We evaluated enriched miRNA profiles, identifying VEGF, Insulin, ErbB, MAPK, Hedgehog, TLR and Hippo signaling pathways as primary regulatory mechanisms enabling complex morphogenetic transformations within tight temporal constraints. Pathway analysis revealed miRNAs as pivotal nodes of interaction, coordinating cascades of gene expression critical for cell fate determination, proliferation, migration, and differentiation across germ layers and developing organ systems. Weighted Gene Co-Expression Network Analysis (WGCNA) generated hub miRNAs whose modular connections spanned regulatory networks, including: gga-miR-181a-3p (blue module), coordinating immunegenesis and myogenesis; gga-miR-126-3p (brown module), regulating vasculogenesis and angiogenesis; gga-miR-302c-5p (turquoise module), enabling pluripotency and self-renew; and gga-miR-429-3p (yellow module), modulating neurogenesis and osteogenesis. The findings of this study extend the knowledge of miRNA expression in early embryonic development of chickens, providing insights into the intricate gene control process that helps ensure proper development.

MAP3K19 Promotes the Progression of Tuberculosis-Induced Pulmonary Fibrosis Through Activation of the TGF-β/Smad2 Signaling Pathway

Tuberculosis-induced pulmonary fibrosis (PF) is a chronic, irreversible interstitial lung disease, which severely affects lung ventilation and air exchange, leading to respiratory distress, impaired lung function, and ultimately death. As previously reported, epithelial-mesenchymal transition (EMT) and fibrosis in type II alveolar epithelial cells (AEC II) are two critical processes that contributes to the initiation and progression of tuberculosis-related PF, but the underlying pathological mechanisms remain unclear. In this study, through performing Real-Time quantitative PCR (RT-qPCR), Western blot, immunohistochemistry, and immunofluorescence staining assay, we confirmed that the expression levels of EMT and fibrosis-related biomarkers were significantly increased in lung tissues with tuberculosis-associated PF in vivo and Mycobacterium bovis Bacillus Calmette-Guérin (BCG) strain-infected AEC II cells in vitro. Besides, we noticed that the mitogen-activated protein kinase 19 (MAP3K19) was aberrantly overexpressed in PF models, and silencing of MAP3K19 significantly reduced the expression levels of fibronectin, collagen type I, and alpha-smooth muscle actin to decrease fibrosis, and upregulated E-cadherin and downregulated vimentin to suppress EMT in BCG-treated AEC II cells. Then, we uncovered the underlying mechanisms and found that BCG synergized with MAP3K19 to activate the pro-inflammatory transforming growth factor-beta (TGF-β)/Smad2 signal pathway in AEC II cells, and BCG-induced EMT process and fibrosis in AEC II cells were all abrogated by co-treating cells with TGF-β/Smad2 signal pathway inhibitor LY2109761. In summary, our results uncovered the underlying mechanisms by which the MAP3K19/TGF-β/Smad2 signaling pathway regulated EMT and fibrotic phenotypes of AEC II cells to facilitate the development of tuberculosis-associated PF, and these findings will provide new ideas and biomarkers to ameliorate tuberculosis-induced PF in clinic.

Pan-Cancer Analysis and Experimental Validation of SOX4 as a Potential Diagnosis, Prognosis, and Immunotherapy Biomarker

INTRODUCTION

SOX4 plays an important role in tumorigenesis and cancer progression. The role of SOX4 in pan-cancer and its underlying molecular mechanism in liver hepatocellular carcinoma (LIHC) are not fully understood. In this study, a comprehensive analysis and experimental validation were performed to explore the function of SOX4 across tumor types.

METHODS

Raw data in regard to SOX4 expression in malignant tumors were downloaded from the TCGA and GTEx databases. The expression levels, prognostic values, genetic mutation, and DNA promoter methylation of SOX4 across tumor types were explored via systematic bioinformatics analysis. The ceRNA regulatory network, immune characteristics, and prognostic models were analyzed in LIHC. Finally, we conducted in vitro experiments including Western blotting, cell proliferative assay, trypan blue staining, and fluorescence microscopy to further explore the function of SOX4 in LIHC.

RESULTS

SOX4 expression was significantly upregulated in 24 tumor types. SOX4 expression level was strongly associated with unfavorable prognoses, genetic mutations, and DNA methylation levels across different tumor types. Especially in LIHC, LINC00152/hsa-miR-139-3p/SOX4 was identified as a crucial ceRNA network. Moreover, this study also provides insight into the roles of SOX4 expression in immune cell infiltration, macrophage polarization, immune subtype, molecular subtype, and immunomodulators, as well as the tumor immune microenvironment (TIME)-related prognosis, in LIHC. The study established six favorable prognostic models to predict LIHC prognosis based on the SOX4-associated genes. Finally, lenvatinib treatment can increase the expression of SOX4 in hepatocellular carcinoma cells and lead to drug resistance. Silencing SOX4 can effectively eliminate the drug resistance caused by lenvatinib treatment and inhibit the proliferation of cancer cells.

CONCLUSIONS

This study highlights that SOX4 may serve as a promising therapeutic target for tumor treatment.

Unpacking the Complexity of Epithelial Plasticity: From Master Regulator Transcription Factors to Non-Coding RNAs

Cellular plasticity in cancer enables adaptation to selective pressures and stress imposed by the tumor microenvironment. This plasticity facilitates the remodeling of cancer cell phenotype and function (such as tumor stemness, metastasis, chemo/radio resistance), and the reprogramming of the surrounding tumor microenvironment to enable immune evasion. Epithelial plasticity is one form of cellular plasticity, which is intrinsically linked with epithelial-mesenchymal transition (EMT). Traditionally, EMT has been regarded as a binary state. Yet, increasing evidence suggests that EMT involves a spectrum of quasi-epithelial and quasi-mesenchymal phenotypes governed by complex interactions between cellular metabolism, transcriptome regulation, and epigenetic mechanisms. Herein, we review the complex cross-talk between the different layers of epithelial plasticity in cancer, encompassing the core layer of transcription factors, their interacting epigenetic modifiers and non-coding RNAs, and the manipulation of cancer immunogenicity in transitioning between epithelial and mesenchymal states. In examining these factors, we provide insights into promising therapeutic avenues and potential anti-cancer targets.

Homotypic Entosis as a Potential Novel Diagnostic Marker in Breast Cancer

Homotypic entotic figures, which are a form of "cell-in-cell" structures, are considered a potential novel independent prognostic marker in various cancers. Nevertheless, the knowledge concerning the biological role of this phenomenon is still unclear. Since breast cancer cells are remarkably entosis-competent, we aimed to investigate and compare the frequency of entoses in a primary breast tumor and in its lymph node metastasis. Moreover, as there are limited data on defined molecular markers of entosis, we investigated entosis in correlation with classical breast cancer biomarkers used in routine pathomorphological diagnostics (HER2, ER, PR, and Ki67). In the study, a cohort of entosis-positive breast cancer samples paired into primary lesions and lymph node metastases was used. The inclusion criteria were a diagnosis of NOS cancer, lymph node metastases, the presence of entotic figures in the primary lesion, and/or lymph node metastases. In a selected, double-negative, HER2-positive NOS breast cancer case, entoses were characterized by a correlation between an epithelial-mesenchymal transition and proliferation markers. We observed that in the investigated cohort entotic figures were positively correlated with Ki67 and HER2, but not with ER or PR markers. Moreover, for the first time, we identified Ki67-positive mitotic inner entotic cells in clinical carcinoma samples. Our study performed on primary and secondary breast cancer specimens indicated that entotic figures, when examined by routine HE histological staining, present potential diagnostic value, since they correlate with two classical prognostic factors of breast cancer.

IOX-1 suppresses metastasis of osteosarcoma by upregulating histone H3 lysine trimethylation

New therapeutic approaches are needed for metastatic osteosarcoma (OS), as survival rates remain low despite surgery and chemotherapy. Epigenetic changes, such as histone H3 methylation, play key roles in many cancers including OS, although the underlying mechanisms are not clear. In this study, human OS tissue and OS cell lines displayed lower levels of histone H3 lysine trimethylation compared with normal bone tissue and osteoblast cells. Treating OS cells with the histone lysine demethylase inhibitor 5-carboxy-8-hydroxyquinoline (IOX-1) dose-dependently increased histone H3 methylation and inhibited cellular migratory and invasive capabilities, suppressed matrix metalloproteinase expression, reversed epithelial-to-mesenchymal transition by increasing levels of epithelial markers E-cadherin and ZO-1 and decreasing the expression of mesenchymal markers N-cadherin, vimentin, and TWIST, and also reduced stemness properties. An analysis of cultivated MG63 cisplatin-resistant (MG63-CR) cells revealed lower histone H3 lysine trimethylation levels compared with levels in MG63 cells. Exposing MG63-CR cells to IOX-1 increased histone H3 trimethylation and ATP-binding cassette transporter expression, potentially sensitizing MG63-CR cells to cisplatin. In conclusion, our study suggests that histone H3 lysine trimethylation is associated with metastatic OS and that IOX-1 or other epigenetic modulators present promising strategies to inhibit metastatic OS progression.

Endoplasmic reticulum stress mediates nickel chloride-induced epithelial‑mesenchymal transition and migration of human lung cancer A549 cells through Smad2/3 and p38 MAPK activation

BACKGROUND

The endoplasmic reticulum (ER) is a cellular membrane-bound organelle whereby proteins are synthesized, folded and glycosylated. Due to intrinsic (e.g., genetic) and extrinsic (e.g., environmental stressors) perturbations, ER proteostasis can be deregulated within cells which triggers unfolded protein response (UPR) as an adaptive stress response that may impact the migration and invasion properties of cancer cells. However, the mechanisms underlying the nickel compounds on lung cancer cell migration and invasion remain uncertain.

OBJECTIVE

We aimed to study whether Nickel chloride (NiCl₂) induces ER stress in lung cancer cells, and whether ER stress is involved in modulating epithelial-mesenchymal transition (EMT) and migration by Smads and MAPKs pathways activation following NiCl₂ treatment.

METHODS

A549 cells were treated with NiCl₂ to determine the cell viability using MTT assay. The wound healing assay was used to evaluate cell migration ability. ER ultrastructure was observed by transmission electron microscopy. Western blotting assay was performed to evaluate the protein levels of BIP, PERK, IRE-1α, XBP-1 s, and ATF6 for ER stress and UPR, E-cadherin and Vimentin for EMT, p-Smad2/3, p-ERK, p-JNK, and p-P38 for activation of Smads and MAPKs signaling pathways.

RESULTS

The expression levels of BIP, PERK, IRE-1α, XBP-1 s, and ATF6 were significantly increased following treatment with NiCl₂ in time- and dose-effect relationship. The ER stress inhibitor 4-PBA downregulated the expression levels of the above five proteins, and reversed the decrease in E-cadherin protein level and the increase in vimentin protein expression and cell migration abilities caused by NiCl₂. Furthermore, 4-PBA significantly reduced nickel chloride-induced Smad2/3 and p38 MAPK pathway activation, while not affected ERK and JNK MAPK pathways.

CONCLUSION

NiCl₂ triggers ER stress and UPR in A549 cells. Moreover, 4-PBA alleviates NiCl₂-induced EMT and migration ability of A549 cells possibly through the Smad2/3 and p38 MAPK pathways activation, rather than ERK and JNK MAPK pathways.

Snail Immunoexpression in Endometrioid Endometrial Carcinomas

Endometrial carcinoma is one of the most prevalent cancers affecting women with epidemiological placing it as the sixth most common cancer in women. One of the factors implicated in EMT (epithelial-mesenchymal transition), Snail is regarded as having a pivotal role. We selected a number of 30 endometrial carcinomas, in a 2-year period (2020-2022). Snail immunoexpression was identified in the tumor cells for 70% of the endometroid carcinoma cases studied. Tumor cells showed both nuclear and cytoplasmic expression but only nuclear signals were quantified. The average percent of marked tumor cells was 38.6±24.9, corresponding to well differentiated carcinomas. Our analysis also showed a significant association between higher tumor grade and snail expression (p=0.000). Alteration of the epithelial-mesenchymal phenotype in endometrial carcinomas by Snail overexpression in high-grade and advanced-stage lesions constitutes mechanisms involved in the process of tumor progression.

The Role of RKIP in the Regulation of EMT in the Tumor Microenvironment

Simple Summary

Raf kinase inhibitor protein (RKIP) expression in cancer cells is significantly reduced and promoting cancer cells growth and invasiveness. Overexpresssion of RKIP has been reported to mediate pleiotropic anti-cancer activities including the inhibition of survival signaling pathways, sensitization to cell death by cytotoxic drugs, inhibition of invasion, EMT and metastasis. The molecular mechanism by which RKIP inhibits EMT is not clear. In this review, we have examined how RKIP inhibits the selected EMT gene products (Snail, vimentin, N-cadherin, laminin alpha) and found that it involves signaling cross-talks between RKIP and each of the EMT gene products. These findings were validated by bioinformatic analyses demonstrating in various human cancers a negative correlation between the expression of RKIP and the expression of the EMT gene products. These findings suggest that targeting RKIP induction in cancer cells will result in multiple hits by inhibiting tumor growth, metastasis and reversal of chemo-immuno resistance.

Abstract

The Raf Kinase Inhibitor Protein (RKIP) is a unique gene product that directly inhibits the Raf/Mek/Erk and NF-kB pathways in cancer cells and resulting in the inhibition of cell proliferation, viability, EMT, and metastasis. Additionally, RKIP is involved in the regulation of cancer cell resistance to both chemotherapy and immunotherapy. The low expression of RKIP expression in many cancer types is responsible, in part, for the pathogenesis of cancer and its multiple properties. The inhibition of EMT and metastasis by RKIP led to its classification as a tumor suppressor. However, the mechanism by which RKIP mediates its inhibitory effects on EMT and metastases was not clear. We have proposed that one mechanism involves the negative regulation by RKIP of the expression of various gene products that mediate the mesenchymal phenotype as well as the positive regulation of gene products that mediate the epithelial phenotype via signaling cross talks between RKIP and each gene product. We examined several EMT mesenchymal gene products such as Snail, vimentin, N-cadherin, laminin and EPCAM and epithelial gene products such as E-cadherin and laminin. We have found that indeed these negative and positive correlations were detected in the signaling cross-talks. In addition, we have also examined bioinformatic data sets on different human cancers and the findings corroborated, in large part, the findings observed in the signaling cross-talks with few exceptions in some cancer types. The overall findings support the underlying mechanism by which the tumor suppressor RKIP regulates the expression of gene products involved in EMT and metastasis. Hence, the development of agent that can selectively induce RKIP expression in cancers with low expressions should result in the activation of the pleiotropic anti-cancer activities of RKIP and resulting in multiple effects including inhibition of tumor cell proliferation, EMT, metastasis and sensitization of resistant tumor cells to respond to both chemotherapeutics and immunotherapeutics.

Epithelial–mesenchymal transition: The history, regulatory mechanism, and cancer therapeutic opportunities

Epithelial–mesenchymal transition (EMT) is a program wherein epithelial cells lose their junctions and polarity while acquiring mesenchymal properties and invasive ability. Originally defined as an embryogenesis event, EMT has been recognized as a crucial process in tumor progression. During EMT, cell–cell junctions and cell–matrix attachments are disrupted, and the cytoskeleton is remodeled to enhance mobility of cells. This transition of phenotype is largely driven by a group of key transcription factors, typically Snail, Twist, and ZEB, through epigenetic repression of epithelial markers, transcriptional activation of matrix metalloproteinases, and reorganization of cytoskeleton. Mechanistically, EMT is orchestrated by multiple pathways, especially those involved in embryogenesis such as TGFβ, Wnt, Hedgehog, and Hippo, suggesting EMT as an intrinsic link between embryonic development and cancer progression. In addition, redox signaling has also emerged as critical EMT modulator. EMT confers cancer cells with increased metastatic potential and drug resistant capacity, which accounts for tumor recurrence in most clinic cases. Thus, targeting EMT can be a therapeutic option providing a chance of cure for cancer patients. Here, we introduce a brief history of EMT and summarize recent advances in understanding EMT mechanisms, as well as highlighting the therapeutic opportunities by targeting EMT in cancer treatment.

MiR-150-5p Overexpression in Triple-Negative Breast Cancer Contributes to the In Vitro Aggressiveness of This Breast Cancer Subtype

Simple Summary

Triple-negative breast cancer (TNBC) is a clinically aggressive type of breast cancer. MicroRNAs (miRNAs) are small molecules that regulate the expression of genes involved in tumor cell signaling. The miR-150-5p is frequently deregulated in cancer, with expression and mode of action varying according to the cancer type. In this study, we investigated the expression levels of miR-150-5p in TNBC, its association with clinical and pathological features of patients, and its role in modulating TNBC cell proliferation, migration, and drug resistance. Our results suggest that miR-150-5p is highly expressed in TNBC and that miR-150-5p expression levels are associated with tumor grade, patient survival, and ethnicity. Our findings also indicate that miR-150-5p contributes to the aggressive phenotypes of TNBC cells in vitro.

Abstract

MiR-150-5p is frequently deregulated in cancer, with expression and mode of action varying according to the tumor type. Here, we investigated the expression levels and role of miR-150-5p in the aggressive breast cancer subtype triple-negative breast cancer (TNBC). MiR-150-5p expression levels were analyzed in tissue samples from 113 patients with invasive breast cancer (56 TNBC and 57 non-TNBC) and 41 adjacent non-tumor tissues (ANT). Overexpression of miR-150-5p was observed in tumor tissues compared with ANT tissues and in TNBC compared with non-TNBC tissues. MiR-150-5p expression levels were significantly associated with high tumor grades and the Caucasian ethnicity. Interestingly, high miR-150-5p levels were associated with prolonged overall survival. Manipulation of miR-150-5p expression in TNBC cells modulated cell proliferation, clonogenicity, migration, and drug resistance. Manipulation of miR-150-5p expression also resulted in altered expression of its mRNA targets, including epithelial-to-mesenchymal transition markers, MYB, and members of the SRC pathway. These findings suggest that miR-150-5p is overexpressed in TNBC and contributes to the aggressiveness of TNBC cells in vitro.

Biochanin A Suppresses Tumor Progression and PD-L1 Expression via Inhibiting ZEB1 Expression in Colorectal Cancer

Objective. To investigate the regulatory effect of ZEB1 on PD-L1 expression and the pharmacodynamic effects of Biochanin A on the malignant biological behaviors of colorectal cancer (CRC). Methods. The correlation between epithelial-mesenchymal transition (EMT) score and features of the tumor microenvironment (TME) was investigated using the Cancer Genome Atlas (TCGA) dataset. The correlation between ZEB1 and PD-L1 expression was validated using immunohistochemistry (IHC) staining, and the regulatory effect of ZEB1 on PD-L1 expression was explored by in vitro assays. Moreover, the pharmacodynamic effects of Biochanin A on ZEB1 and PD-L1 expression, as well as malignant biological behaviors of CRC cells, were evaluated by in vitro and in vivo assays. Results. EMT score was positively correlated with a majority of immunostimulators, immune checkpoints, activities of antitumor immunity cycles, and infiltration levels of most immune cells in the TCGA dataset. In addition, ZEB1 was correlated with and positively regulated PD-L1 expression in CRC. Besides, Biochanin A, an inhibitor for the ZEB1/PD-L1 axis, notably inhibited ZEB1-mediated aggressiveness and PD-L1 expression of CRC cells. Moreover, Biochanin A also exerted a tumor-inhibitory role in vivo in the CRC mouse model. Conclusion. Overall, we found that ZEB1 is a main regulator of PD-L1 expression in CRC. In addition, we also identified Biochanin A as a novel inhibitor for the ZEB1/PD-L1 axis, which could inhibit tumor progression and immune escape.

The NMD Pathway Regulates GABARAPL1 mRNA during the EMT

EMT is a reversible cellular process that is linked to gene expression reprogramming, which allows for epithelial cells to undergo a phenotypic switch to acquire mesenchymal properties. EMT is associated with cancer progression and cancer therapeutic resistance and it is known that, during the EMT, many stress response pathways, such as autophagy and NMD, are dysregulated. Therefore, our goal was to study the regulation of ATG8 family members (GABARAP, GABARAPL1, LC3B) by the NMD and to identify molecular links between these two cellular processes that are involved in tumor development and metastasis formation. IHC experiments, which were conducted in a cohort of patients presenting lung adenocarcinomas, showed high GABARAPL1 and low UPF1 levels in EMT+ tumors. We observed increased levels of GABARAPL1 correlated with decreased levels of NMD factors in A549 cells in vitro. We then confirmed that GABARAPL1 mRNA was indeed targeted by the NMD in a 3′UTR-dependent manner and we identified four overlapping binding sites for UPF1 and eIF4A3 that are potentially involved in the recognition of this transcript by the NMD pathway. Our study suggests that 3′UTR-dependent NMD might be an important mechanism that is involved in the induction of autophagy and could represent a promising target in the development of new anti-cancer therapies.