miR205 inhibits stem cell renewal in SUM159PT breast cancer cells

Non-coding RNAs, a double-edged sword in breast cancer prognosis

Cancer is a rising issue worldwide, and numerous studies have focused on understanding the underlying reasons for its occurrence and finding proper ways to defeat it. By applying technological advances, researchers are continuously uncovering and updating treatments in cancer therapy. Their vast functions in the regulation of cell growth and proliferation and their significant role in the progression of diseases, including cancer. This review provides a comprehensive analysis of ncRNAs in breast cancer, focusing on long non-coding RNAs such as HOTAIR, MALAT1, and NEAT1, as well as microRNAs such as miR-21, miR-221/222, and miR-155. These ncRNAs are pivotal in regulating cell proliferation, metastasis, drug resistance, and apoptosis. Additionally, we discuss experimental approaches that are useful for studying them and highlight the advantages and challenges of each method. We then explain the results of these clinical trials and offer insights for future studies by discussing major existing gaps. On the basis of an extensive number of studies, this review provides valuable insights into the potential of ncRNAs in cancer therapy. Key findings show that even though the functions of ncRNAs are vast and undeniable in cancer, there are still complications associated with their therapeutic use. Moreover, there is an absence of sufficient experiments regarding their application in mouse models, which is an area to work on. By emphasizing the crucial role of ncRNAs, this review underscores the need for innovative approaches and further studies to explore their potential in cancer therapy.

Extracellular vesicles-miR-205-5p inhibits lymphatic metastasis in pancreatic cancer through diffusely downregulating VEGFA

Pancreatic ductal adenocarcinoma (PDAC) is to become the second leading cause of cancer-related death by 2040. Many factors contribute to this dilemma, including lymphatic metastasis, which is the primary cause of PDAC metastasis. The inhibition of early lymph node metastasis, including the lymphangiogenic process, may be a novel strategy for PDAC treatment. Through miRNA sequencing of plasma extracellular vesicles (EVs) from PDAC patients, for the first time, we identified that plasma EV-miR-205-5p served as a non-invasive biomarker distinguishing lymphatic metastasis status (N0 vs. N2) in PDAC patients. Using tissue microarray and in situ hybridization, we discovered that miR-205-5p was highly expressed in PDAC, but negatively correlated with lymph node metastasis. By in vivo and in vitro experiments, we demonstrated its unique mechanism of action via EV-mediated transfer to human lymphatic endothelial cells (HLECs), leading to systematic downregulation of VEGFA and inhibition of the Akt/Erk pathway, which suppressed lymphangiogenesis. Delivering miR-205-5p via engineered EVs might be a promising strategy to eliminate PDAC lymphatic metastasis and improve prognosis.

Role of microRNAs in triple‑negative breast cancer and new therapeutic concepts (Review)

Breast cancer has surpassed lung cancer as the most prevalent malignancy affecting women worldwide. Triple-negative breast cancer (TNBC) is the type of breast cancer with the worst prognosis. As a heterogeneous disease, TNBC has a pathogenesis that involves multiple oncogenic pathways, including involvement of gene mutations and alterations in signaling pathways. MicroRNAs (miRNAs) are small endogenous, single-stranded non-coding RNAs that bind to the 3' untranslated region of target cell mRNAs to negatively regulate the gene expression of these specific mRNAs. Therefore, miRNAs are involved in cell growth, development, division and differentiation stages. miRNAs are also involved in gene targeting in tumorigenesis, tumor growth and the regulation of metastasis, including in breast cancer. Meanwhile, miRNAs also regulate components of signaling pathways. In this review, the role of miRNAs in the TNBC signaling pathway discovered in recent years is described in detail. The new concept of bi-targeted therapy for breast cancer using miRNA and artificial intelligence is also discussed.

Cancer stem cells: The important role of CD markers, Signaling pathways, and MicroRNAs

For the first time, a subset of small cancer cells identified in acute myeloid leukemia has been termed Cancer Stem Cells (CSCs). These cells are notorious for their robust proliferation, self-renewal abilities, significant tumor-forming potential, spread, and resistance to treatments. CSCs are a global concern, as it found in numerous types of cancer, posing a real-world challenge today. Our review encompasses research on key CSC markers, signaling pathways, and MicroRNA in three types of cancer: breast, colon, and liver. These factors play a critical role in either promoting or inhibiting cancer cell growth. The reviewed studies have shown that as cells undergo malignant transformation, there can be an increase or decrease in the expression of different Cluster of Differentiation (CD) markers on their surface. Furthermore, alterations in essential signaling pathways, such as Wnt and Notch1, may impact CSC proliferation, survival, and movement, while also providing potential targets for cancer therapies. Additionally, some research has focused on MicroRNAs due to their dual role as potential therapeutic biomarkers and their ability to enhance CSCs' response to anti-cancer drugs. MicroRNAs also regulate a wide array of cellular processes, including the self-renewal and pluripotency of CSCs, and influence gene transcription. Thus, these studies indicate that MicroRNAs play a significant role in the malignancy of various tumors. Although the gathered information suggests that specific CSC markers, signaling pathways, and MicroRNAs are influential in determining the destiny of cancer cells and could be advantageous for therapeutic strategies, their precise roles and impacts remain incompletely defined, necessitating further investigation.

Hippo-YAP/TAZ signaling in breast cancer: Reciprocal regulation of microRNAs and implications in precision medicine

Breast cancer is a molecularly heterogeneous disease and the most common female malignancy. In recent years, therapy approaches have evolved to accommodate molecular diversity, with a focus on more biologically based therapies to minimize negative consequences. To regulate cell fate in human breast cells, the Hippo signaling pathway has been associated with the alpha subtype of estrogen receptors. This pathway regulates tissue size, regeneration, and healing, as well as the survival of tissue-specific stem cells, proliferation, and apoptosis in a variety of organs, allowing for cell differentiation. Hippo signaling is mediated by the kinases MST1, MST2, LATS1, and LATS2, as well as the adaptor proteins SAV1 and MOB. These kinases phosphorylate the downstream effectors of the Hippo pathway, yes-associated protein (YAP), and transcriptional coactivator with PDZ-binding motif (TAZ), suppressing the expression of their downstream target genes. The Hippo signaling pathway kinase cascade plays a significant role in all cancers. Understanding the principles of this kinase cascade would prevent the occurrence of breast cancer. In recent years, small noncoding RNAs, or microRNAs, have been implicated in the development of several malignancies, including breast cancer. The interconnections between miRNAs and Hippo signaling pathway core proteins in the breast, on the other hand, remain poorly understood. In this review, we focused on highlighting the Hippo signaling system, its key parts, its importance in breast cancer, and its regulation by miRNAs and other related pathways.

Extirpating the cancer stem cell hydra: Differentiation therapy and Hyperthermia therapy for targeting the cancer stem cell hierarchy

Ever since the discovery of cancer stem cells (CSCs), they have progressively attracted more attention as a therapeutic target. Like the mythical hydra, this subpopulation of cells seems to contribute to cancer immortality, spawning more cells each time that some components of the cancer cell hierarchy are destroyed. Traditional modalities focusing on cancer treatment have emphasized apoptosis as a route to eliminate the tumor burden. A major problem is that cancer cells are often in varying degrees of dedifferentiation contributing to what is known as the CSCs hierarchy and cells which are known to be resistant to conventional therapy. Differentiation therapy is an experimental therapeutic modality aimed at the conversion of malignant phenotype to a more benign one. Hyperthermia therapy (HT) is a modality exploiting the changes induced in cells by the application of heat produced to aid in cancer therapy. While differentiation therapy has been successfully employed in the treatment of acute myeloid leukemia, it has not been hugely successful for other cancer types. Mounting evidence suggests that hyperthermia therapy may greatly augment the effects of differentiation therapy while simultaneously overcoming many of the hard-to-treat facets of recurrent tumors. This review summarizes the progress made so far in integrating hyperthermia therapy with existing modules of differentiation therapy. The focus is on studies related to the successful application of both hyperthermia and differentiation therapy when used alone or in conjunction for hard-to-treat cancer cell niche with emphasis on combined approaches to target the CSCs hierarchy.

Advances in the expression and function of Fyn in different human tumors

The tyrosine kinase Fyn is a member of the SRC family of kinases, and its sustained activation is closely linked to tumor cell migration, proliferation, and cell metabolism. Recently, Fyn has been found to be expressed in various tumor tissues, and the expression and function of Fyn vary between tumors, with Fyn acting as an oncogene to promote proliferation and metastasis in some tumors. This article summarizes the recent studies on the role of Fyn in different human tumors, focusing on the role of Fyn in melanoma, breast cancer, glioma, lung cancer, and peripheral T-cell lymphoma in order to provide a basis for future research and targeted therapy in different human tumors.

MicroRNAs: The key players regulating the crosstalk between Hippo and Wnt/β-catenin pathways in breast cancer

Breast Cancer has the highest burden in females worldwide and is predicted to increase by many folds with increasing lifestyle related risk factors, genetic mutations, and an aging population. The Hippo signalling and Wnt signalling pathways were identified as important signal transducers involved in maintaining organ development, tissue homeostasis, cell proliferation and apoptosis. microRNAs are short nucleotide sequences which act as regulatory components driving signal transductions in most cancers and can serve as both diagnostic and prognostic markers. Several reports have implicated that deregulated Hippo as well as Wnt signalling mediated by miRNAs together drive tumorigenesis, metastases and chemoresistance in breast cancer. Recent evidences on a crosstalk between Hippo and Wnt components elucidated how these pathways might be synchronized to have overlapping functions to promote tumorigenesis. Since miRNAs are demonstrated to target most of the components in both the pathways, in this review, we talk about the crosstalk between Hippo and Wnt signalling pathways and the potential microRNAs that might regulate the interplay between the two pathways in breast cancer, which has not been explored earlier.

Utilizing the Hippo pathway as a therapeutic target for combating endocrine-resistant breast cancer

Drug resistance is always a great obstacle in any endocrine therapy of breast cancer. Although the combination of endocrine therapy and targeted therapy has been shown to significantly improve prognosis, refractory endocrine resistance is still common. Dysregulation of the Hippo pathway is often related to the occurrence and the development of many tumors. Targeted therapies of this pathway have played important roles in the study of triple negative breast cancer (TNBC). Targeting the Hippo pathway in combination with chemotherapy or other targeted therapies has been shown to significantly improve specific antitumor effects and reduce cancer antidrug resistance. Further exploration has shown that the Hippo pathway is closely related to endocrine resistance, and it plays a "co-correlation point" role in numerous pathways involving endocrine resistance, including related pathways in breast cancer stem cells (BCSCs). Agents and miRNAs targeting the components of the Hippo pathway are expected to significantly enhance the sensitivity of breast cancer cells to endocrine therapy. This review initially explains the possible mechanism of the Hippo pathway in combating endocrine resistance, and it concludes by recommending endocrine therapy in combination with therapies targeting the Hippo pathway in the study of endocrine-resistant breast cancers.

Signaling pathways governing breast cancer stem cells behavior

Breast cancer is the second common cancer and the leading cause of malignancy among females overall. Breast cancer stem cells (BCSCs) are a small population of breast cancer cells that play a critical role in the metastasis of breast cancer to other organs in the body. BCSCs have both self-renewal and differentiation capacities, which are thought to contribute to the aggressiveness of metastatic lesions. Therefore, targeting BCSCs can be a suitable approach for the treatment and metastasis of breast cancer. Growing evidence has indicated that the Wnt, NFκB, Notch, BMP2, STAT3, and hedgehog (Hh) signaling pathways govern epithelial-to-mesenchymal transition (EMT) activation, growth, and tumorigenesis of BCSCs in the primary regions. miRNAs as the central regulatory molecules also play critical roles in BCSC self-renewal, metastasis, and drug resistance. Hence, targeting these pathways might be a novel therapeutic approach for breast cancer diagnosis and therapy. This review discusses known signaling mechanisms involved in the stimulation or prevention of BCSC self-renewal, metastasis, and tumorigenesis.

Inhibition Sequence of miR-205 Hinders the Cell Proliferation and Migration of Lung Cancer Cells by Regulating PETN-Mediated PI3K/AKT Signal Pathway

The aim of this study was to identify the pro-tumor role of miR-205 in patients with lung cancer (LC) on the cell proliferation and migration through regulating PTEN-mediated PI3K/AKT signal pathway. Paired cancer tissues and adjacent tissues were collected from 107 LC patients who received treatment in Jinan Central hospital. In addition, the purchased LC cell lines were transfected into HCC827 cell line to observe and compare the biological behaviors. Compared with adjacent tissues, miR-205 was statistically higher in LC tissues, while PTEN was notably lower (P < 0.05). Inhibition of miR-205 not only suppressed cell proliferation, migration and invasion, increased apoptosis rate, but regulated epithelial mesenchymal transformation (EMT)-related proteins. Likewise, overexpression of PETN played the same role as that of miR-205 inhibition sequence. Inhibited miR-205 or PTEN overexpression brought dramatically decreased PI3K and p-Akt. The relationship between miR-205 and PTEN was verified through the biological prediction website and luciferase reporter. Co-transfection experiments revealed that after cotransfection of miR-205 inhibitor and si-PETN, the cell proliferation and invasion showed no marked difference between cotransfection group and NC group. MiR-205 is involved in LC cell proliferation and migration by regulating PETN-mediated PI3K/AKT signal pathway, which may be a feasible treatment target for LC in clinical practice.

Progress of non-coding RNAs in triple-negative breast cancer

Non-coding RNAs (ncRNAs) include miRNA, lncRNA, and circRNA. NcRNAs are involved in multiple biological processes, including chromatin remodeling, signal transduction, post-transcriptional modification, cell autophagy, carbohydrate metabolism, and cell cycle regulation. Triple negative breast cancer (TNBC) is notorious for high invasiveness and metastasis, poor prognosis, and high mortality, and it is the most malignant breast cancer, while the effective targets for TNBC treatment are still lacking. NcRNAs act as oncogenes or suppressor genes, as well as promote or inhibit the occurrence and development of TNBC. Here, we reviewed some important miRNAs, lncRNAs, circRNAs, their target(s) and molecular mechanisms in TNBC. It is benefited to understand the occurrence and development of TNBC, further some ncRNAs might be potential targets for TNBC treatment.

MicroRNAs, a Promising Target for Breast Cancer Stem Cells

Reactivation of the stem cell programme in breast cancer is significantly associated with persistent cancer progression and therapeutic failure. Breast cancer stem cells (BCSCs) are involved in the process of breast cancer initiation, metastasis and cancer relapse. Among the various important cues found in the formation and progression of BCSCs, microRNAs (miRNAs or miRs) play a pivotal role by regulating the expression of various tumour suppressor genes or oncogenes. Accordingly, there is evidence that miRNAs are associated with BCSC self-renewal, differentiation, invasion, metastasis and therapy resistance, and therefore cancer recurrence. miRNAs execute their roles by regulating the expression of stemness markers, activation of signalling pathways or their components and regulation of transcription networks in BCSCs. Therefore, a better understanding of the association between BCSCs and miRNAs has the potential to help design more effective and safer therapeutic solutions against breast cancer. Thus, an miRNA-based therapeutic strategy may open up new horizons for the treatment of breast cancer in the future. In view of this, we present the progress to date of miRNA research associated with stemness marker expression, signalling pathways and activation of transcription networks to regulate the self-renewal, differentiation and therapy resistance properties of BCSCs.

The Relevance of the SH2 Domain for c-Src Functionality in Triple-Negative Breast Cancer Cells

The role of Src family kinases (SFKs) in human tumors has been always associated with tyrosine kinase activity and much less attention has been given to the SH2 and SH3 adapter domains. Here, we studied the role of the c-Src-SH2 domain in triple-negative breast cancer (TNBC). To this end, SUM159PT and MDA-MB-231 human cell lines were employed as model systems. These cells conditionally expressed, under tetracycline control (Tet-On system), a c-Src variant with point-inactivating mutation of the SH2 adapter domain (R175L). The expression of this mutant reduced the self-renewal capability of the enriched population of breast cancer stem cells (BCSCs), demonstrating the importance of the SH2 adapter domain of c-Src in the mammary gland carcinogenesis. In addition, the analysis of anchorage-independent growth, proliferation, migration, and invasiveness, all processes associated with tumorigenesis, showed that the SH2 domain of c-Src plays a very relevant role in their regulation. Furthermore, the transfection of two different aptamers directed to SH2-c-Src in both SUM159PT and MDA-MB-231 cells induced inhibition of their proliferation, migration, and invasiveness, strengthening the hypothesis that this domain is highly involved in TNBC tumorigenesis. Therefore, the SH2 domain of c-Src could be a promising therapeutic target and combined treatments with inhibitors of c-Src kinase enzymatic activity may represent a new therapeutic strategy for patients with TNBC, whose prognosis is currently very negative.

MicroRNA regulation of cancer stem cells in the pathogenesis of breast cancer

Breast cancer is the most common cancer among women and accounts for 30% of all female malignancies worldwide. Breast cancer stem cells (BCSCs) are a small population of breast cancer cells that exhibit multiple characteristics including differentiation capacity, self-renewal and therapeutic resistance. Recently, BCSCs have attracted attention due to their modulation of breast tumor behaviors and drug resistance. miRNAs are small noncoding mRNAs involved in virtually all biological processes, including stem cell development, maintenance and differentiation. In breast cancer, miRNAs appear to be multi-faceted since they can act as either suppressors or oncogenes to regulate breast cancer progression. This review summarizes the critical roles of miRNAs in regulating multiple signaling pathways such as Wnt/β-catenin, Notch, PI3K/AKT/mTOR, BMI-1 and STAT3 that are important for the BCSC maintenance.

Targeting SRC Kinase Signaling in Pancreatic Cancer Stem Cells

The proto-oncogene nonreceptor tyrosine-protein kinase SRC is a member of the SRC family of tyrosine kinases (SFKs), and its activation and overexpression have been shown to play a protumorigenic role in multiple solid cancers, including pancreatic ductal adenocarcinoma (PDAC). PDAC is currently the seventh-leading cause of cancer-related death worldwide, and, by 2030, it is predicted to become the second-leading cause of cancer-related death in the United States. PDAC is characterized by its high lethality (5-year survival of rate of <10%), invasiveness, and chemoresistance, all of which have been shown to be due to the presence of pancreatic cancer stem cells (PaCSCs) within the tumor. Due to the demonstrated overexpression of SRC in PDAC, we set out to determine if SRC kinases are important for PaCSC biology using pharmacological inhibitors of SRC kinases (dasatinib or PP2). Treatment of primary PDAC cultures established from patient-derived xenografts with dasatinib or PP2 reduced the clonogenic, self-renewal, and tumor-initiating capacity of PaCSCs, which we attribute to the downregulation of key signaling factors such as p-FAK, p-ERK1-2, and p-AKT. Therefore, this study not only validates that SRC kinases are relevant and biologically important for PaCSCs but also suggests that inhibitors of SRC kinases may represent a possible future treatment option for PDAC patients, although further studies are still needed.

c-Src functionality controls self-renewal and glucose metabolism in MCF7 breast cancer stem cells

Deregulation of Src kinases is associated with cancer. We previously showed that SrcDN conditional expression in MCF7 cells reduces tumorigenesis and causes tumor regression in mice. However, it remained unclear whether SrcDN affected breast cancer stem cell functionality or it reduced tumor mass. Here, we address this question by isolating an enriched population of Breast Cancer Stem Cells (BCSCs) from MCF7 cells with inducible expression of SrcDN. Induction of SrcDN inhibited self-renewal, and stem-cell marker expression (Nanog, Oct3-4, ALDH1, CD44). Quantitative proteomic analyses of mammospheres from MCF7-Tet-On-SrcDN cells (data are available via ProteomeXchange with identifier PXD017789, project DOI: 10.6019/PXD017789) and subsequent GSEA showed that SrcDN expression inhibited glycolysis. Indeed, induction of SrcDN inhibited expression and activity of hexokinase, pyruvate kinase and lactate dehydrogenase, resulting in diminished glucose consumption and lactate production, which restricted Warburg effect. Thus, c-Src functionality is important for breast cancer stem cell maintenance and renewal, and stem cell transcription factor expression, effects linked to glucose metabolism reduction.

Prognostic Role of microRNA-205 in Human Gynecological Cancer: A Meta-Analysis of Fourteen Studies

Several studies have revealed that miR-205 plays important roles in the development of gynecological cancers and thus may serve as a potential prognostic biomarker, but the current conclusions remain controversial. Therefore, the goal of this study was to explore the prognostic significance and functional mechanisms of miR-205 based on a meta-analysis and bioinformatics investigation. A total of 14 published studies containing 5835 patients were enrolled by searching the PubMed, EMBASE, and Cochrane library databases, 13 (14 datasets) and 5 (6 datasets) of which evaluated the correlations between the expression level of miR-205 and overall survival (OS) or disease-free survival (DFS)/disease-specific survival (DSS)/progression-free survival (PFS)/distant metastasis-free survival (DMFS), respectively. Furthermore, the use of online Kaplan-Meier plotter database analysis supplemented another seven results for OS. Then, a meta-analysis using these 21 and 6 datasets was performed. As a result, the overall analysis failed to demonstrate any significant associations between miR-205 expression and OS (p = 0.267) or DSS/DFS/DMFS/PFS (p = 0.457), but the subgroup analysis suggested that elevated miR-205 predicted a reduced OS for breast cancer (BC) patients (hazard ratio [HR] = 0.84, 95% confidence interval [CI] = 0.72-0.98; p = 0.022), while higher miR-205 was associated with a poor DSS for endometrial cancer (EC) patients (HR = 2.19, 95% CI = 1.45-3.32; p < 0.001). Function prediction analysis indicated that miR-205 may be involved in BC by negatively influencing hub genes, SMARCA5 and SIAH1, whereas miR-205 may participate in EC by negatively modulating BMPR1B because of the presence of interactions of miR-205 with them at 3'-untranslated region and their opposite prognosis outcomes with miR-205. In conclusion, our findings suggest miR-205 may be a promising prognostic biomarker and therapeutic target for BC and EC patients.

Role of miRNA-Regulated Cancer Stem Cells in the Pathogenesis of Human Malignancies

Recent biomedical discoveries have revolutionized the concept and understanding of carcinogenesis, a complex and multistep phenomenon which involves accretion of genetic, epigenetic, biochemical, and histological changes, with special reference to MicroRNAs (miRNAs) and cancer stem cells (CSCs). miRNAs are small noncoding molecules known to regulate expression of more than 60% of the human genes, and their aberrant expression has been associated with the pathogenesis of human cancers and the regulation of stemness features of CSCs. CSCs are the small population of cells present in human malignancies well-known for cancer resistance, relapse, tumorigenesis, and poor clinical outcome which compels the development of novel and effective therapeutic protocols for better clinical outcome. Interestingly, the role of miRNAs in maintaining and regulating the functioning of CSCs through targeting various oncogenic signaling pathways, such as Notch, wingless (WNT)/β-Catenin, janus kinases/ signal transducer and activator of transcription (JAK/STAT), phosphatidylinositol 3-kinase/ protein kinase B (PI3/AKT), and nuclear factor kappa-light-chain-enhancer of activated B (NF-kB), is critical and poses a huge challenge to cancer treatment. Based on recent findings, here, we have documented the regulatory action or the underlying mechanisms of how miRNAs affect the signaling pathways attributed to stemness features of CSCs, such as self-renewal, differentiation, epithelial to mesenchymal transition (EMT), metastasis, resistance and recurrence etc., associated with the pathogenesis of various types of human malignancies including colorectal cancer, lung cancer, breast cancer, head and neck cancer, prostate cancer, liver cancer, etc. We also shed light on the fact that the targeted attenuation of deregulated functioning of miRNA related to stemness in human carcinogenesis could be a viable approach for cancer treatment.

Low let-7d and high miR-205 expression levels positively influence HNSCC patient outcome

Introduction

Head and neck squamous carcinoma (HNSCC) is one of the most invasive types of cancer with high mortality. A previous study has indicated that low levels of let-7d and miR-205 in HNSCC patients are correlated with poor survival. Let-7d and miR-205 are tumor suppressors and regulators of epithelial-to-mesenchymal transition (EMT). However, it is unclear if let-7d and miR-205 together influence cancer cells.

Aim

To determine if let-7d and miR-205 expression levels influence HNSCC patient outcome.

Methods

The TCGA expression data for let-7d, miR-205 and their targets as well as clinical data were downloaded from cBioPortal and starBase v2.0 for 307 patients. The expression levels of let-7d and miR-205 were verified according to clinicopathological parameters. The let-7d and miR-205 high- and low-expression groups as well as disease-free survival (DFS), overall survival (OS) and expression levels of genes related to EMT, cancer stem cells, metastasis, cell cycle, drug response and irradiation response were investigated.

Results

Let-7d and miR-205 were frequently upregulated in HNSCC compared to normal samples, and ROC analysis showed high discrimination ability for let-7d and miR-205 (area 0.7369 and 0.7739, respectively; p < 0.0001). Differences between expression levels of let-7d or miR-205 and grade, angiolymphatic invasion, perineural invasion and alcohol consumption were indicated. No differences were observed in N-stage, tumor localization, gender or patient age. Patients with lower let-7d levels and higher miR-205 levels had significantly better OS (p = 0.0325) than patients with higher let-7d levels and lower miR-205 levels. In the low let-7d level and high miR-205 level group, a lower percentage of more advanced cancers was observed. The analysis of genes related to EMT, cancer stem cells, metastasis, cell cycle, drug response and irradiation response revealed a distinct phenotype of analyzed groups.

Conclusions

The present findings indicated that let-7d down-regulation and miR-205 overexpression create a unique cell phenotype with different behavior compared to cells with upregulated let-7d and down-regulated miR-205. Thus, let-7d and miR-205 are good candidates for new HNSCC biomarkers.

Overview on Epigenetic Re-programming: A Potential Therapeutic Intervention in Triple Negative Breast Cancers

Breast cancer treatments leads to variable responses. Hormonal therapy is beneficial to receptor positive breast cancer subtypes and display better clinical outcome than triple negative breast cancers (TNBCs) with FEC (5-Fluorouracil, Epirubicin and Cyclophosphamide) the mainstay chemotherapy regiment. Owning to their negative expressions of estrogen (ER), progesterone (PR) and HER2 receptors, disease recurrence and metastasis befalls some patients indicating resistance to FEC. Involvement of epigenetic silencing through DNA methylation, histone methylation, acetylation and sumoylation may be the key player in FEC chemoresistance. Epigenetic and molecular profiling successfully classified breast cancer subtypes, indicating potential driver mechanisms to the progression of TNBCs but functional mechanisms behind chemoresistance of these molecular markers are not well defined. Several epigenetic inhibitors and drugs have been used in the management of cancers but these attempts are mainly beneficial in hematopoietic cancers and not specifically favourable in solid tumours. Hypothetically, upon administration of epigenetic drugs, recovery of tumour suppressor genes is expected. However, high tendency of switching on global metastatic genes is predicted. Polycomb repressive complex (PRC) such as EZH2, SETD1A, DNMT, is known to have repressive effects in gene regulation and shown to inhibit cell proliferation and invasion in breast cancers. Individual epigenetic regulators may be an option to improve chemo-drug delivery in cancers. This review discussed on molecular signatures of various breast cancer subtypes and on-going attempts in understanding underlying molecular mechanisms of epigenetic regulators as well as providing insights on possible ways to utilize epigenetic enzymes/inhibitors with responses to chemotherapeutic drugs to re-program cellular and biological outcome in TNBCs.