Aberrant Promoter Methylation of YAP Gene and its Subsequent Downregulation in Indian Breast Cancer Patients

The molecular crosstalk of the hippo cascade in breast cancer: A potential central susceptibility

The incidence of breast cancer is perpetually growing globally, and it remains a major public health problem and the leading cause of mortality in women. Though the aberrant activities of the Hippo pathway have been reported to be associated with cancer, constructive knowledge of the pathway connecting the various elements of breast cancer remains to be elucidated. The Hippo transducers, yes-associated protein (YAP) and transcriptional co-activator with PDZ binding motif (TAZ), are reported to be either tumor suppressors, oncogenes, or independent prognostic markers in breast cancer. Thus, there is further need for an explicative evaluation of the dilemma with this molecular contribution of Hippo transducers in modulating breast malignancy. In this review, we summarize the intricate crosstalk of the Hippo pathway in different aspects of breast malignancy, including stem-likeness, cellular signaling, metabolic adaptations, tumor microenvironment, and immune responses. The collective data shows that Hippo transducers play an indispensable role in mammary tumor formation, progression, and dissemination. However, the cellular functions of YAP/TAZ in tumorigenesis might be largely dependent on the mechanical and biophysical cues they interact with, as well as on the cell phenotype. This review provides a glimpse into the plausible biological contributions of the cascade to the inward progression of breast carcinoma and suggests potential therapeutic prospects.

Combination of verteporfin-photodynamic therapy with 5-aza-2'-deoxycytidine enhances the anti-tumour immune response in triple negative breast cancer

Introduction

Triple negative breast cancer (TNBC) is a subtype of breast cancer characterised by its high tumourigenic, invasive, and immunosuppressive nature. Photodynamic therapy (PDT) is a focal therapy that uses light to activate a photosensitizing agent and induce a cytotoxic effect. 5-aza-2'-deoxycytidine (5-ADC) is a clinically approved immunomodulatory chemotherapy agent. The mechanism of the combination therapy using PDT and 5-ADC in evoking an anti-tumour response is not fully understood.

Methods

The present study examined whether a single dose of 5-ADC enhances the cytotoxic and anti-tumour immune effect of low dose PDT with verteporfin as the photosensitiser in a TNBC orthotopic syngeneic murine model, using the triple negative murine mammary tumour cell line 4T1. Histopathology analysis, digital pathology and immunohistochemistry of treated tumours and distant sites were assessed. Flow cytometry of splenic and breast tissue was used to identify T cell populations. Bioinformatics were used to identify tumour immune microenvironments related to TNBC patients.

Results

Functional experiments showed that PDT was most effective when used in combination with 5-ADC to optimize its efficacy. 5-ADC/PDT combination therapy elicited a synergistic effect in vitro and was significantly more cytotoxic than monotherapies on 4T1 tumour cells. For tumour therapy, all types of treatments demonstrated histopathologically defined margins of necrosis, increased T cell expression in the spleen with absence of metastases or distant tissue destruction. Flow cytometry and digital pathology results showed significant increases in CD8 expressing cells with all treatments, whereas only the 5-ADC/PDT combination therapy showed increase in CD4 expression. Bioinformatics analysis of in silico publicly available TNBC data identified BCL3 and BCL2 as well as the following anti-tumour immune response biomarkers as significantly altered in TNBC compared to other breast cancer subtypes: GZMA, PRF1, CXCL1, CCL2, CCL4, and CCL5. Interestingly, molecular biomarker assays showed increase in anti-tumour response genes after treatment. The results showed concomitant increase in BCL3, with decrease in BCL2 expression in TNBC treatment. In addition, the treatments showed decrease in PRF1, CCL2, CCL4, and CCL5 genes with 5-ADC and 5-ADC/PDT treatment in both spleen and breast tissue, with the latter showing the most decrease.

Discussion

To our knowledge, this is the first study that shows which of the innate and adaptive immune biomarkers are activated during PDT related treatment of the TNBC 4T1 mouse models. The results also indicate that some of the immune response biomarkers can be used to monitor the effectiveness of PDT treatment in TNBC murine model warranting further investigation in human subjects.

YAP/TAZ: Molecular pathway and disease therapy

The Yes-associated protein and its transcriptional coactivator with PDZ-binding motif (YAP/TAZ) are two homologous transcriptional coactivators that lie at the center of a key regulatory network of Hippo, Wnt, GPCR, estrogen, mechanical, and metabolism signaling. YAP/TAZ influences the expressions of downstream genes and proteins as well as enzyme activity in metabolic cycles, cell proliferation, inflammatory factor expression, and the transdifferentiation of fibroblasts into myofibroblasts. YAP/TAZ can also be regulated through epigenetic regulation and posttranslational modifications. Consequently, the regulatory function of these mechanisms implicates YAP/TAZ in the pathogenesis of metabolism-related diseases, atherosclerosis, fibrosis, and the delicate equilibrium between cancer progression and organ regeneration. As such, there arises a pressing need for thorough investigation of YAP/TAZ in clinical settings. In this paper, we aim to elucidate the signaling pathways that regulate YAP/TAZ and explore the mechanisms of YAP/TAZ-induce diseases and their potential therapeutic interventions. Furthermore, we summarize the current clinical studies investigating treatments targeting YAP/TAZ. We also address the limitations of existing research on YAP/TAZ and propose future directions for research. In conclusion, this review aims to provide fresh insights into the signaling mediated by YAP/TAZ and identify potential therapeutic targets to present innovative solutions to overcome the challenges associated with YAP/TAZ.

The Hippo Pathway Effectors YAP/TAZ-TEAD Oncoproteins as Emerging Therapeutic Targets in the Tumor Microenvironment

Various cancer cell-associated intrinsic and extrinsic inputs act on YAP/TAZ proteins to mediate the hyperactivation of the TEAD transcription factor-based transcriptome. This YAP/TAZ-TEAD activity can override the growth-limiting Hippo tumor-suppressor pathway that maintains normal tissue homeostasis. Herein, we provide an integrated summary of the contrasting roles of YAP/TAZ during normal tissue homeostasis versus tumor initiation and progression. In addition to upstream factors that regulate YAP/TAZ in the TME, critical insights on the emerging functions of YAP/TAZ in immune suppression and abnormal vasculature development during tumorigenesis are illustrated. Lastly, we discuss the current methods that intervene with the YAP/TAZ-TEAD oncogenic signaling pathway and the emerging applications of combination therapies, gut microbiota, and epigenetic plasticity that could potentiate the efficacy of chemo/immunotherapy as improved cancer therapeutic strategies.

FOXO3 gene hypermethylation and its marked downregulation in breast cancer cases: A study on female patients

Background

FOXO3, a member of the FOX transcription factor family, is frequently described as being deregulated in cancer. Additionally, notable role of FOXO3 can be easily recognized in the process of ageing and survival. Even though various studies have been done to acknowledge the tumour-suppressive or oncogenic role of FOXO3 in cancer, still there exist a lack of understanding in terms of cancer prognosis and treatment. Therefore, to provide better insight, our study aims to evaluate the role and function of FOXO3 in breast cancer in Indian female patients. We examined the FOXO3 expression levels in breast cancer samples by analyzing mRNA and protein expression along with its clinicopathological parameters.

Results

A total of 127 cases of breast cancer with equal normal cases (n=127) were assessed with methylation (MS-PCR), Immunohistochemistry (IHC), mRNA expression using Real-time PCR was analysed and 66.14% cases at mRNA level were found to be downregulated, while 81.10% of cases had little or very little protein expression. Our data state, the promoter hypermethylation of the FOXO3 gene and the downregulated protein expression are significantly correlated (p=0.0004). Additionally, we found a significant correlation between the level of FOXO3 mRNA with ER (p=0.04) and status of lymph node (p=0.01) along with this.

Conclusion

Data suggests the prognostic significance and the tumour-suppressive role of FOXO3 in breast cancer cases studied in India. However, there is a need for the extended research targeting FOXO3 to measure its clinical potential and develop well-defined therapeutic strategies.

LncRNA KCNQ1OT1 promotes the metastasis of ovarian cancer by increasing the methylation of EIF2B5 promoter

Background

Long non-coding RNAs (lncRNAs) have emerged as regulators of human malignancies, including ovarian cancer (OC). LncRNA KCNQ1OT1 could promote OC progression, and EIF2B5 was associated with development of several tumors. This project was aimed to explore the role of lncRNA KCNQ1OT1 in OC development, as well as the involving action mechanism.

Methods

Reverse transcription quantitative polymerase chain reaction (RT-qPCR) or Western blotting was employed to determine the expression levels of KCNQ1OT1 and EIF2B5. OC cell proliferation was evaluated by MTT and colony formation assays, and wound healing and Transwell assays were implemented to monitor cell migration and invasion, respectively. The methylation status of EIF2B5 promoter was examined by MS-PCR, to clarify whether the expression of EIF2B5 was decreased. The binding activity of KCNQ1OT1 to methyltransferases DNMT1, DNMT3A and DNMT3B was determined by dual luciferase reporter assay or RIP assay, to explore the potential of KCNQ1OT1 alters the expression of its downstream gene. ChIP assay was carried out to verify the combination between EIF2B5 promoter and above three methyltransferases.

Results

Expression of lncRNA KCNQ1OT1 was increased in OC tissues and cells. EIF2B5 expression was downregulated in OC, which was inversely correlated with KCNQ1OT1. Knockdown of KCNQ1OT1 inhibited OC cell proliferation and metastasis. KCNQ1OT1 could downregulate EIF2B5 expression by recruiting DNA methyltransferases into EIF2B5 promoter. Furthermore, interference of EIF2B5 expression rescued KCNQ1OT1 depletion-induced inhibitory impact on OC cell proliferation and metastasis.

Conclusion

Our findings evidenced that lncRNA KCNQ1OT1 aggravated ovarian cancer metastasis by decreasing EIF2B5 expression level, and provided a novel therapeutic strategy for OC.

LncRNA KCNQ1OT1 is upregulated, while EIF2B5 is downregulated in OC tissues and cells.

Knockdown of KCNQ1OT1 represses OC cell proliferation and metastasis.

KCNQ1OT1 decreases EIF2B5 expression by recruiting DNA methyltransferases into EIF2B5 promoter, thereby promoting OC progression.

Hippo-TAZ signaling is the master regulator of the onset of triple-negative basal-like breast cancers

Breast cancer is the most frequent malignancy in women worldwide. Basal-like breast cancer (BLBC) is the most aggressive form of this disease, and patients have a poor prognosis. Here, we present data suggesting that the Hippo-transcriptional coactivator with PDZ-binding motif (TAZ) pathway is a key driver of BLBC onset and progression. Deletion of Mob1a/b in mouse mammary luminal epithelium induced rapid and highly reproducible mammary tumorigenesis that was dependent on TAZ but not yes-associated protein 1 (YAP1). In situ early-stage BLBC-like malignancies developed in mutant animals by 2 wk of age, and invasive BLBC appeared by 4 wk. In a human estrogen receptor⁺ luminal breast cancer cell line, TAZ hyperactivation skewed the features of these luminal cells to the basal phenotype, consistent with the aberrant TAZ activation frequently observed in human precancerous BLBC lesions. TP53 mutation is rare in human precancerous BLBC but frequent in invasive BLBC. Addition of Trp53 deficiency to our Mob1a/b-deficient mouse model enhanced tumor grade and accelerated cancer progression. Our work justifies targeting the Hippo-TAZ pathway as a therapy for human BLBC, and our mouse model represents a powerful tool for evaluating candidate agents.

Hippo signaling pathway: A comprehensive gene expression profile analysis in breast cancer

Breast cancer (BC) is the most frequently diagnosed malignancy in women and a major public health concern. The Hippo pathway is an evolutionarily conserved signaling pathway that serves as a key regulator for a wide variety of biological processes. Hippo signaling has been shown to have both oncogenic and tumor-suppressive functions in various cancers. Core components of the Hippo pathway consist of various kinases and downstream effectors such as YAP/TAZ. In the current report, differential expression of Hippo pathway elements as well as the correlation of Hippo pathway mRNAs with various clinicopathologic characteristics, including molecular subtypes, receptor status, and methylation status, has been investigated in BC using METABRIC and TCGA datasets. In this review, we note deregulation of several Hippo signaling elements in BC patients. Moreover, we see examples of negative correlations between methylation of Hippo genes and mRNA expression. The expression of Hippo genes significantly varies between different receptor subgroups. Because of the clear associations between mRNA expression and methylation status, DNA methylation may be one of the mechanisms that regulate the Hippo pathway in BC cells. Differential expression of Hippo genes among various BC molecular subtypes suggests that Hippo signaling may function differently in different subtypes of BC. Our data also highlights an interesting link between Hippo components' transcription and ER negativity in BC. In conclusion, substantial deregulation of Hippo signaling components suggests an important role of these genes in breast cancer.

The Interaction Between Autophagy and JAK/STAT3 Signaling Pathway in Tumors

Tumor is one of the important factors affecting human life and health in today’s world, and scientists have studied it extensively and deeply, among which autophagy and JAK/STAT3 signaling pathway are two important research directions. The JAK/STAT3 axis is a classical intracellular signaling pathway that assumes a key role in the regulation of cell proliferation, apoptosis, and vascular neogenesis, and its abnormal cell signaling and regulation are closely related to the occurrence and development of tumors. Therefore, the JAK/STAT3 pathway in tumor cells and various stromal cells in their microenvironment is often considered as an effective target for tumor therapy. Autophagy is a process that degrades cytoplasmic proteins and organelles through the lysosomal pathway. It is a fundamental metabolic mechanism for intracellular degradation. The mechanism of action of autophagy is complex and may play different roles at various stages of tumor development. Altered STAT3 expression has been found to be accompanied by the abnormal autophagy activity in many oncological studies, and the two may play a synergistic or antagonistic role in promoting or inhibiting the occurrence and development of tumors. This article reviews the recent advances in autophagy and its interaction with JAK/STAT3 signaling pathway in the pathogenesis, prevention, diagnosis, and treatment of tumors.

Analysis of Yes-Associated Protein-1 (YAP1) Target Gene Signature to Predict Progressive Breast Cancer

Breast cancers are treated according to the ER/PR or HER2 expression and show better survival outcomes with targeted therapy. Triple-negative breast cancers (TNBCs) with a lack of expression of ER/PR and HER2 are treated with systemic therapy with unpredictable responses and outcomes. It is essential to investigate novel markers to identify targeted therapies for TNBC. One such marker is YAP1, a transcription co-activator protein that shows association with poor prognosis of breast cancer. YAP1 transcriptionally regulates the expression of genes that drive the oncogenic phenotypes. Here, we assess a potential YAP target gene signature to predict a progressive subset of breast tumors from METABRIC and TCGA datasets. YAP1 target genes were shortlisted based on expression correlation and concordance with YAP1 expression and significant association with survival outcomes of patients. Hierarchical clustering was performed for the shortlisted genes. The utility of the clustered genes was assessed by survival analysis to identify a recurring subset. Expression of the shortlisted target genes showed significant association with survival outcomes of HER2-positive and TNBC subset in both datasets. The shortlisted genes were verified using an independent dataset. Further validation using IHC can prove the utility of this potential prognostic signature to identify a recurrent subset of HER2-positive and TNBC subtypes.

FOXO1 Gene Downregulation and Promoter Methylation Exhibits Significant Correlation With Clinical Parameters in Indian Breast Cancer Patients

Background: Forkhead box “O” one which is member of Forkhead box family of transcription factors is known to play key role in different physiological processes including cell cycle arrest, autophagy, and apoptosis. FOXO1 is defined to play tumor suppressive role in various malignancies including breast cancer and its Dysregulation is frequently reported. However, the evaluation of FOXO1 promoter methylation and its expression at mRNA and protein level in different stages of breast cancer and its association with different clinical parameters is still not studied. Therefore, for better understanding the role of FOXO1 in breast cancer, in our study we examined the FOXO1 mRNA and protein expression in Breast cancer samples of Indian breast cancer patients.

Results: Total 127 breast cancer samples along with adjacent normal tissue (n = 127) were analyzed through methylation specific PCR (MS-PCR), mRNA expression (Real-time PCR) and Immunohistochemistry (IHC). We detected 69.29% cases to be downregulated at the mRNA level, and 77.95% of cases exhibited no or low protein expression. In our data we report a significant association (p = 0.0001) between the downregulated protein expression and promoter hypermethylation of FOXO1 gene. We also found a significant correlation of FOXO1 mRNA level with Age (p = 0.008), age at first live birth (p = 0,003), tumor size (p = 0.05) and lymph node status (p = 0.01).

Conclusion: we in our study report the tumor suppressive role of FOXO1 in case of Indian breast cancer patients and our data suggest it to exhibit prognostic importance. However, further research is needed to evaluate FOXO1 significance in diagnostic and therapeutic targeting in breast cancer cases.

Discovering the key genes and important DNA methylation regions in breast cancer

Background

Breast cancer is the malignant tumor with the highest incidence in women. DNA methylation has an important effect on breast cancer, but the effect of abnormal DNA methylation on gene expression in breast cancer is still unclear. Therefore, it is very important to find therapeutic targets related to DNA methylation.

Results

In this work, we calculated the DNA methylation distribution and gene expression level in cancer and para-cancerous tissues for breast cancer samples. We found that DNA methylation in key regions is closely related to gene expression by analyzing the relationship between the distribution characteristics of DNA methylation in different regions and the change of gene expression level. Finally, the 18 key genes (17 tumor suppressor genes and 1 oncogene) related to prognosis were confirmed by the survival analysis of clinical data. Some important DNA methylation regions in these genes that result in breast cancer were found.

Conclusions

We believe that 17 TSGs and 1 oncogene may be breast cancer biomarkers regulated by DNA methylation in key regions. These results will help to explore DNA methylation biomarkers as potential therapeutic targets for breast cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41065-022-00220-5.

Epigenetic Regulation of the Wnt/β-Catenin Signaling Pathway in Cancer

Studies over the past four decades have elucidated the role of Wnt/β-catenin mediated regulation in cell proliferation, differentiation and migration. These processes are fundamental to embryonic development, regeneration potential of tissues, as well as cancer initiation and progression. In this review, we focus on the epigenetic players which influence the Wnt/β-catenin pathway via modulation of its components and coordinated regulation of the Wnt target genes. The role played by crosstalk with other signaling pathways mediating tumorigenesis is also elaborated. The Hippo/YAP pathway is particularly emphasized due to its extensive crosstalk via the Wnt destruction complex. Further, we highlight the recent advances in developing potential therapeutic interventions targeting the epigenetic machinery based on the characterization of these regulatory networks for effective treatment of various cancers and also for regenerative therapies.

Increased YAP1 expression is significantly associated with breast cancer progression, metastasis and poor survival

YAP1 plays a key role as a transcriptional coactivator in the Hippo pathway. Based on conflicting reports regarding YAP1 function in cancer, this study discerned its role in breast carcinogenesis. First, a systematic review of salient breast cancer studies targeting YAP1 dysregulation was performed. Additionally, freshly excised tumor specimens of approximately 200 breast cancer patients were processed for quantification of YAP1 expression at mRNA and protein levels using quantitative PCR and immunohistochemistry, respectively. YAP1 expression was nine folds higher in tumors versus controls and significantly associated with metastasis (p < 0.05) and poor survival in Pakistani breast cancer patients. These findings establish the role of YAP1 overexpression in tumorigenesis and metastasis. Hence, YAP1 inhibition may be considered a possible therapeutic strategy.

Isorhapontigenin protects against doxorubicin-induced cardiotoxicity via increasing YAP1 expression

As an effective anticancer drug, the clinical limitation of doxorubicin (Dox) is the time- and dose-dependent cardiotoxicity. Yes-associated protein 1 (YAP1) interacts with transcription factor TEA domain 1 (TEAD1) and plays an important role in cell proliferation and survival. However, the role of YAP1 in Dox-induced cardiomyopathy has not been reported. In this study, the expression of YAP1 was reduced in clinical human failing hearts with dilated cardiomyopathy and Dox-induced in vivo and in vitro cardiotoxic model. Ectopic expression of Yap1 significantly blocked Dox-induced cardiomyocytes apoptosis in TEAD1 dependent manner. Isorhapontigenin (Isor) is a new derivative of stilbene and responsible for a wide range of biological processes. Here, we found that Isor effectively relieved Dox-induced cardiomyocytes apoptosis in a dose-dependent manner in vitro. Administration with Isor (30 mg/kg/day, intraperitoneally, 3 weeks) significantly protected against Dox-induced cardiotoxicity in mice. Interestingly, Isor increased Dox-caused repression in YAP1 and the expression of its target genes in vivo and in vitro. Knockout or inhibition of Yap1 blocked the protective effects of Isor on Dox-induced cardiotoxicity. In conclusion, YAP1 may be a novel target for Dox-induced cardiotoxicity and Isor might be a new compound to fight against Dox-induced cardiotoxicity by increasing YAP1 expression.

Regulation of Hippo signaling and triple negative breast cancer progression by an ubiquitin ligase RNF187

Breast cancer is the most common malignancy for women worldwide, while Triple Negative Breast Cancer (TNBC) accounts for 20% in all patients. Compared with estrogen receptor positive breast cancer, which could be effectively controlled via endocrine therapy, TNBC is more aggressive and worse in prognosis. It is therefore urgent and necessary to develop a novel therapeutic strategy for TNBC treatment. Recent studies identified Hippo signaling is highly activated in TNBC, which could be a driving pathway for TNBC progression. In our study, we determine RNF187 as a negative regulator for Hippo signaling activation. RNF187 depletion significantly decreases cell migration and invasion capacity in TNBC. These effects could be rescued by further YAP depletion. Depletion of RNF187 increases the YAP protein level and Hippo signaling target genes, such as CTGF and CYR61 in TNBC. Immuno-precipitation assay shows that RNF187 associates with YAP, promoting its degradation possibly via inducing YAP K48-dependent poly-ubiquitination. Interestingly, Our clinical data reveals that RNF187 reversely correlates with YAP protein level and Hippo target genes. RNF187 tends to correlate with good prognosis in TNBC patients. Our study provides evidence to establish a proteolytic mechanism in regulation Hippo signaling activation in TNBC.

Aberrant methylation of yes-associated protein (YAP1) as a potential biomarker in breast cancer

Background

Breast cancer (BC) represents the most prevalent malignancy among women, and it is characterized by high mortality especially in late stages. BC tumorigenesis was linked to epigenetic alterations namely methylation. Yes-associated protein (YAP1) is the leading downstream effector of the Hippo pathway. It may enhance or inhibit oncogenesis based on the tissue involved.

Aim

This case-control study aimed to analyze the methylation degree of promoter region of YAP1 gene in BC patients by applying methylation-specific polymerase chain reaction (MSP) analysis.

Methods

Genomic deoxyribonucleic acid (DNA) was isolated from 50 paired tumor and adjacent noncancerous breast tissue samples and subjected to bisulfite conversion. Methylation condition of YAP1 gene was studied by MSP and evaluated as a possible biomarker for diagnosing BC and its differentiation from corresponding normal tissues. We also correlated the aberrant methylation with clinicopathological criteria.

Results

Increased methylation of the YAP1 gene promoter region in BC tumor tissue was detected in 68% of the studied BC tissue samples. There was a significant change in the frequency of YAP1 methylated genotype between breast tumor tissues compared to that in adjacent non-cancerous tissue (p < 0.001). YAP1 can discriminate early from late-stage BC with a sensitivity of 96.88% and specificity of 83.33%.

Conclusions

Gene analysis of YAP1 using conventional MSP in tissue specimens can be considered a possible biomarker to distinguish BC from normal breast tissue as well as between early- and late-stage BC.

Mutation, methylation and expression analysis of LIFR gene in Indian breast cancer patients

LIFR functions as a tumor suppressor and metastatic suppressor of breast cancer. The present study investigates the status of LIFR gene in Indian breast cancer patients. A total of 137 breast cancer tissue and 137 adjacent normal tissue which served as controls were analyzed for mutation by automated DNA sequencing, methylation through methylation-specific polymerase chain reaction and its corresponding expression at mRNA and protein level using real-time quantitative polymerase chain reaction and immunohistochemistry respectively in Indian breast cancer patients. All the molecular findings were statistically correlated with clinopathological parameters of the patients to identify its association. LIFR mRNA expression was found to be 2.534 ± 3.52 fold downregulated with subsequent absence of protein in 67.15% cases (92/137). The absence of LIFR protein coincided with 80.95% (85/105) methylated cases thereby showing a very strong correlation among the LIFR promoter methylation and LIFR protein expression (p = 0.0001). We also observed G2968C nucleotide change in 6/137 cases of exon 20 of LIFR gene resulting in Glu990Gln mutation. Correlation of LIFR promoter methylation with geographic location and age at menopause and LIFR mutation with age at menarche, age at first live birth, molecular subtypes of breast cancer, and lymph node status remained significant even after bonferroni correction (p ≤ 0.0027). All these data suggests the relevance of these associations in relation to Indian breast cancer patients. The loss of LIFR protein was frequently found in Indian breast cancer patients, and aberrant promoter methylation showed a significant correlation with its downregulation.

YAP-independent mechanotransduction drives breast cancer progression

Increased tissue stiffness is a driver of breast cancer progression. The transcriptional regulator YAP is considered a universal mechanotransducer, based largely on 2D culture studies. However, the role of YAP during in vivo breast cancer remains unclear. Here, we find that mechanotransduction occurs independently of YAP in breast cancer patient samples and mechanically tunable 3D cultures. Mechanistically, the lack of YAP activity in 3D culture and in vivo is associated with the absence of stress fibers and an order of magnitude decrease in nuclear cross-sectional area relative to 2D culture. This work highlights the context-dependent role of YAP in mechanotransduction, and establishes that YAP does not mediate mechanotransduction in breast cancer.

Histone deacetylase 8 triggers the migration of triple negative breast cancer cells via regulation of YAP signals

Triple-negative breast cancer (TNBC) shows highly aggressive clinical behaviors and poor prognosis compared to other breast cancer subtypes. Histone deacetylases (HDACs) can regulate the progression of various cancers, but the role of HDAC8 in TNBC remains unexplored. Here, we found that HDAC8 enhanced the in vitro migration abilities of breast cancer cells. Targeted inhibition of HDAC8 via si-HDAC8 and its selective inhibitor PCI34051 could suppress the migration of cells. In TNBC cells, HDAC8 stabilized the expression and increased the nuclear localization of YAP, a major downstream effector of Hippo pathway. While silencing YAP could attenuate HDAC8 triggered migration of TNBC cells. Mechanistically, HDAC8 suppressed the phosphorylation of YAP^Ser127, which was related to its cytoplasmic sequestration degradation. Our data revealed that HDAC8 could trigger the migration of TNBC cells via regulation of Hippo-YAP signals, suggesting that HDAC8 might be a potential target for TNBC therapy.