Pivotal role of reduced let-7g expression in breast cancer invasion and metastasis

MicroRNAs as Endocrine Modulators of Breast Cancer

Breast cancer is an aggressive disease of multiple subtypes with varying phenotypic, hormonal, and clinicopathological features, offering enhanced resistance to conventional therapeutic regimens. There is an unmet need for reliable molecular biomarkers capable of detecting the malignant transformation from the early stages of the disease to enhance diagnosis and treatment outcomes. A subset of small non-coding nucleic acid molecules, micro ribonucleic acids (microRNAs/miRNAs), have emerged as promising biomarkers due to their role in gene regulation and cancer pathogenesis. This review discusses, in detail, the different origins and hormone-like regulatory functionalities of miRNAs localized in tumor tissue and in the circulation, as well as their inherent stability and turnover that determines the utility of miRNAs as biomarkers for disease detection, monitoring, prognosis, and therapeutic targets.

Lin28/let-7 axis in breast cancer

Let-7 microRNAs are tumor suppressor microRNAs, and their reduced expression frequently occurs in various types of cancers, including breast cancer. A notable correlation exists between decreased let-7 microRNA levels and the overexpression of Lin28A and Lin28B, particularly in breast cancer cases with poor prognoses. Dysregulation of Wnt signaling significantly contributes to the upregulation of Lin28A and Lin28B in breast cancer. Both Lin28A and Lin28B operate from different cellular compartments to inhibit the biogenesis of let-7 microRNAs, which are essential for the post-transcriptional regulation of genes involved in key cellular functions such as proliferation, differentiation, and apoptosis. Decreased expression of let-7 microRNAs leads to the overexpression of oncogenes such as K-ras, C-myc, and SOX-2 in breast cancer. Overexpression of Lin28A associated with reduced let-7 microRNA levels is observed in estrogen receptor positive, estrogen receptor negative, and human epidermal growth factor receptor 2 positive breast cancers, whereas Lin28B overexpression with reduced let-7 microRNA levels occurs specifically in triple negative breast cancer. This review aims to dissect the molecular interplay between Lin28A, Lin28B, and let-7 microRNAs, elucidating their roles in breast carcinogenesis, metastasis, and the development of resistance to conventional treatments like radiation and chemotherapy. Additionally, the review addresses potential therapeutic avenues offered by let-7 microRNAs or their mimics, as well as Lin28A and Lin28B inhibitors, in the treatment of breast cancer.

SATB1 in cancer progression and metastasis: mechanisms and therapeutic potential

Cancer remains a major global health challenge, with prostate cancer, lung cancer, colorectal cancer, and breast cancer accounting for nearly half of all diagnoses. Despite advancements in cancer treatment, metastasis to distant organs continues to be the leading cause of cancer-related mortality. The progression of cancer involves the alteration of numerous genes, with dynamic changes in chromatin organization and histone modifications playing a critical role in regulating cancer-associated genes. Special AT-rich sequence-binding protein 1 (SATB1), a critical chromatin organizer, plays a pivotal role in cancer progression by regulating gene expression, chromatin remodeling, and cell signaling pathways. SATB1 binds to AT-rich DNA sequences, acting as a scaffold for chromatin-modifying enzymes and transcription factors, thus coordinating the regulation of extensive gene networks. Its overexpression has been implicated in a wide range of cancers and is associated with poor prognosis, aggressive tumor phenotypes, and enhanced epithelial-mesenchymal transition (EMT). Moreover, SATB1's activity is modulated by microRNAs (miRNAs) and post-translational modifications, further contributing to its complex regulatory functions. Given its crucial involvement in cancer progression and metastasis, SATB1 has emerged as a promising target for novel therapeutic strategies. This review delves into the molecular mechanisms of SATB1 in cancer and explores potential therapeutic approaches for targeting this key regulator in cancer treatment.

The Role of Estrogen in Brain MicroRNAs Regulation

Purpose

This review aims to elucidate the role of estrogen-sensitive microRNAs (miRNAs) in modulating brain functions and disorders, highlighting the protective effects of estrogen on the central nervous system.

Methods

A comprehensive literature review was conducted, examining the relationship between estrogen, miRNAs, and cognitive health. The study focused on experimental data comparing cognitive impairments between genders and the mechanisms of estrogen's effects on brain function.

Results

Cognitive impairments are less prevalent in women of reproductive age compared to men, indicating estrogen's neuroprotective role. Estrogen modulates gene expression through specific receptors, while miRNAs regulate approximately 30% of protein-coding genes in mammals. These miRNAs play critical roles in synaptic plasticity and neuronal survival. The review identifies several estrogen-sensitive miRNAs and their potential involvement in brain disorders.

Conclusion

The interplay between estrogen and miRNAs offers valuable insights into the molecular mechanisms underlying cognitive health and disease. Understanding these relationships may lead to novel therapeutic strategies for addressing various brain disorders, particularly those associated with hormonal changes and aging.

The Estrogen-Autophagy Axis: Insights into Cytoprotection and Therapeutic Potential in Cancer and Infection

Macroautophagy, commonly referred to as autophagy, is an essential cytoprotective mechanism that plays a significant role in cellular homeostasis. It has emerged as a promising target for drug development aimed at treating various cancers and infectious diseases. However, the scientific community has yet to reach a consensus on the most effective approach to manipulating autophagy, with ongoing debates about whether its inhibition or stimulation is preferable for managing these complex conditions. One critical factor contributing to the variability in treatment responses for both cancers and infectious diseases is estrogen, a hormone known for its diverse biological effects. Given the strong correlations observed between estrogen signaling and autophagy, this review seeks to summarize the intricate molecular mechanisms that underlie the dual cytoprotective effects of estrogen signaling in conjunction with autophagy. We highlight recent findings from studies that involve various ligands, disease contexts, and cell types, including immune cells. Furthermore, we discuss several factors that regulate autophagy in the context of estrogen's influence. Ultimately, we propose a hypothetical model to elucidate the regulatory effects of the estrogen-autophagy axis on cell fate. Understanding these interactions is crucial for advancing our knowledge of related diseases and facilitating the development of innovative treatment strategies.

Live-Cell Imaging of MicroRNA Expression via Photoinduced Electron Transfer Controlled by Catalytic Hairpin Assembly

MicroRNAs (miRNAs) serve as emerging biomarkers for a range of diseases, and their quantitative analysis draws increasing attention. Yet, current invasive methods limit continuous tracking within living cells. To overcome this, a nonenzymatic DNA-based nanoprobe is developed for dynamic, noninvasive miRNA tracking via live-cell imaging. This probe features a unique hairpin DNA structure with five guanines that act as internal quenchers, suppressing fluorescence from an attached fluorophore via photoinduced electron transfer. Target miRNA initiates toehold-mediated strand displacement, restoring, and amplifying the fluorescence signal. Additionally, by introducing a single mismatch to the hairpin DNA, the nanoprobe's sensitivity is significantly enhanced, lowering the detection limit to about 60 pM without compromising specificity. To optimize intracellular delivery for prolonged monitoring, the nanoprobe is encapsulated within multilamellar lipid nanovesicles, fluorescently labeled for dual-wavelength ratiometric analysis. The proposed nanoprobe demonstrates a significant advance in live-cell miRNA detection, promising enhanced in situ analysis for a better understanding of miRNAs' pathophysiological function.

Profiling canine mammary tumors: A potential model for studying human breast cancer

Despite all clinical progress recorded in the last decades, human breast cancer (HBC) remains a major challenge worldwide both in terms of its incidence and its management. Canine mammary tumors (CMTs) share similarities with HBC and represent an alternative model for HBC. The utility of the canine model in studying HBC relies on their common features, include spontaneous development, subtype classification, mutational profile, alterations in gene expression profile, and incidence/prevalence. This review describes the similarities between CMTs and HBC regarding genomic landscape, microRNA expression alteration, methylation, and metabolomic changes occurring during mammary gland carcinogenesis. The primary purpose of this review is to highlight the advantages of using the canine model as a translational animal model for HBC research and to investigate the challenges and limitations of this approach.

The oncogenic function of PLAGL2 is mediated via ASCL2 and IGF2 and a Wnt-independent mechanism in colorectal cancer

Colorectal cancer (CRC) tumorigenesis and progression are linked to common oncogenic mutations, especially in the tumor suppressor APC, whose loss triggers the deregulation of TCF4/β-Catenin activity. CRC tumorigenesis is also driven by multiple epimutational modifiers such as transcriptional regulators. We describe the common (and near-universal) activation of the zinc finger transcription factor and Let-7 target PLAGL2 in CRC and find that it is a key driver of intestinal epithelial transformation. PLAGL2 drives proliferation, cell cycle progression, and anchorage-independent growth in CRC cell lines and nontransformed intestinal cells. Investigating effects of PLAGL2 on downstream pathways revealed very modest effects on canonical Wnt signaling. Alternatively, we find pronounced effects on the direct PLAGL2 target genes IGF2, a fetal growth factor, and ASCL2, an intestinal stem cell-specific bHLH transcription factor. Inactivation of PLAGL2 in CRC cell lines has pronounced effects on ASCL2 reporter activity. Furthermore, ASCL2 expression can partially rescue deficits of proliferation and cell cycle progression caused by depletion of PLAGL2 in CRC cell lines. Thus, the oncogenic effects of PLAGL2 appear to be mediated via core stem cell and onco-fetal pathways, with minimal effects on downstream Wnt signaling.NEW & NOTEWORTHY A Let-7 target called PLAGL2 drives oncogenic transformation via Wnt-independent pathways. This work illustrates the robust effects of this zinc finger transcription factor in colorectal cancer (CRC) cell lines and nontransformed intestinal epithelium, with effects mediated, in part, via the direct target genes ASCL2 and IGF2. This has implications for the role of PLAGL2 in activation of onco-fetal and onco-stem cell pathways, contributing to immature and highly proliferative phenotypes in CRC.

Lin28B overexpression decreases let-7b and let-7g levels and increases proliferation and estrogen secretion in Dolang sheep ovarian granulosa cells

Although ovine puberty initiation has been previously studied, the mechanism by which the RNA-binding protein Lin28B affects this process has not been investigated. The present study aimed to investigate the effects of Lin28B overexpression on let-7b, let-7g, cell proliferation, and estrogen secretion in Dolang sheep ovine ovarian granulosa cells. In this study, a Lin28B vector was constructed and transfected into ovarian granulosa cells using liposomes. After 24, 48, and 72 h of overexpression, quantitative real-time PCR (qRT-PCR) was used for measuring let-7b and let-7g microRNA (miRNA) levels, and estrogen secretion was measured using the enzyme-linked immunosorbent assay (ELISA). A CCK-8 (Cell Counting Kit-8) kit was used for evaluating cell viability and proliferation in response to Lin28B overexpression at 24 h. The results showed that the expression of let-7b and let-7g decreased significantly after Lin28B overexpression, and the difference was consistent over different periods. The result of ELISA showed that estradiol (E2) levels significantly increased following Lin28B overexpression. Additionally, Lin28B overexpression significantly increased the cell viability and proliferation. Therefore, the Lin28B-let-7 family axis may play a key role in the initiation of female ovine puberty.

The role of LIN28B in tumor progression and metastasis in solid tumor entities

LIN28B is an RNA-binding protein that targets a broad range of microRNAs and modulates their maturation and activity. Under normal conditions, LIN28B is exclusively expressed in embryogenic stem cells, blocking differentiation and promoting proliferation. In addition, it can play a role in epithelial-to-mesenchymal transition by repressing the biogenesis of let-7 microRNAs. In malignancies, LIN28B is frequently overexpressed, which is associated with increased tumor aggressiveness and metastatic properties. In this review, we discuss the molecular mechanisms of LIN28B in promoting tumor progression and metastasis in solid tumor entities and its potential use as a clinical therapeutic target and biomarker.

Epi-miRNAs: Modern mediators of methylation status in human cancers

Methylation of the fundamental macromolecules, DNA/RNA, and proteins, is remarkably abundant, evolutionarily conserved, and functionally significant in cellular homeostasis and normal tissue/organism development. Disrupted methylation imprinting is strongly linked to loss of the physiological equilibrium and numerous human pathologies, and most importantly to carcinogenesis, tumor heterogeneity, and cancer progression. Mounting recent evidence has documented the active implication of miRNAs in the orchestration of the multicomponent cellular methylation machineries and the deregulation of methylation profile in the epigenetic, epitranscriptomic, and epiproteomic levels during cancer onset and progression. The elucidation of such regulatory networks between the miRNome and the cellular methylation machineries has led to the emergence of a novel subclass of miRNAs, namely "epi-miRNAs" or "epi-miRs." Herein, we have summarized the existing knowledge on the functional role of epi-miRs in the methylation dynamic landscape of human cancers and their clinical utility in modern cancer diagnostics and tailored therapeutics. This article is categorized under: RNA in Disease and Development > RNA in Disease.

Human Milk-Derived Levels of let-7g-5p May Serve as a Diagnostic and Prognostic Marker of Low Milk Supply in Breastfeeding Women

Low milk supply (LMS) is associated with early breastfeeding cessation; however, the biological underpinnings in the mammary gland are not understood. MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally downregulate gene expression, and we hypothesized the profile of miRNAs secreted into milk reflects lactation performance. Longitudinal changes in milk miRNAs were measured using RNAseq in women with LMS (n = 47) and adequate milk supply (AMS; n = 123). Relationships between milk miRNAs, milk supply, breastfeeding outcomes, and infant weight gain were assessed, and interactions between milk miRNAs, maternal diet, smoking status, and BMI were determined. Women with LMS had lower milk volume (p = 0.003), were more likely to have ceased breast feeding by 24 wks (p = 0.0003) and had infants with a lower mean weight-for-length z-score (p = 0.013). Milk production was significantly associated with milk levels of miR-16-5p (R = -0.14, adj p = 0.044), miR-22-3p (R = 0.13, adj p = 0.044), and let-7g-5p (R = 0.12, adj p = 0.046). Early milk levels of let-7g-5p were significantly higher in mothers with LMS (adj p = 0.0025), displayed an interaction between lactation stage and milk supply (p < 0.001), and were negatively related to fruit intake (p = 0.015). Putative targets of let-7g-5p include genes important to hormone signaling, RNA regulation, ion transport, and the extracellular matrix, and down-regulation of two targets (PRLR and IGF2BP1/IMP1) was confirmed in mammary cells overexpressing let-7g-5p in vitro. Our data provide evidence that milk-derived miRNAs reflect lactation performance in women and warrant further investigation to assess their utility for predicting LMS risk and early breastfeeding cessation.

Identification of miRNA biomarkers for breast cancer by combining ensemble regularized multinomial logistic regression and Cox regression

BACKGROUND

Breast cancer is one of the most common cancers in women. It is necessary to classify breast cancer subtypes because different subtypes need specific treatment. Identifying biomarkers and classifying breast cancer subtypes is essential for developing appropriate treatment methods for patients. MiRNAs can be easily detected in tumor biopsy and play an inhibitory or promoting role in breast cancer, which are considered promising biomarkers for distinguishing subtypes.

RESULTS

A new method combing ensemble regularized multinomial logistic regression and Cox regression was proposed for identifying miRNA biomarkers in breast cancer. After adopting stratified sampling and bootstrap sampling, the most suitable sample subset for miRNA feature screening was determined via ensemble 100 regularized multinomial logistic regression models. 124 miRNAs that participated in the classification of at least 3 subtypes and appeared at least 50 times in 100 integrations were screened as features. 22 miRNAs from the proposed feature set were further identified as the biomarkers for breast cancer by using Cox regression based on survival analysis. The accuracy of 5 methods on the proposed feature set was significantly higher than on the other two feature sets. The results of 7 biological analyses illustrated the rationality of the identified biomarkers.

CONCLUSIONS

The screened features can better distinguish breast cancer subtypes. Notably, the genes and proteins related to the proposed 22 miRNAs were considered oncogenes or inhibitors of breast cancer. 9 of the 22 miRNAs have been proved to be markers of breast cancer. Therefore, our results can be considered in future related research.

Lin28 Regulates Cancer Cell Stemness for Tumour Progression

Tumours develop therapy resistance through complex mechanisms, one of which is that cancer stem cell (CSC) populations within the tumours present self-renewable capability and phenotypical plasticity to endure therapy-induced stress conditions and allow tumour progression to the therapy-resistant state. Developing therapeutic strategies to cope with CSCs requires a thorough understanding of the critical drivers and molecular mechanisms underlying the aforementioned processes. One such hub regulator of stemness is Lin28, an RNA-binding protein. Lin28 blocks the synthesis of let-7, a tumour-suppressor microRNA, and acts as a global regulator of cell differentiation and proliferation. Lin28also targets messenger RNAs and regulates protein translation. In this review, we explain the role of the Lin28/let-7 axis in establishing stemness, epithelial-to-mesenchymal transition, and glucose metabolism reprogramming. We also highlight the role of Lin28 in therapy-resistant prostate cancer progression and discuss the emergence of Lin28-targeted therapeutics and screening methods.

The biomimetic extracellular matrix: a therapeutic tool for breast cancer research

A deeper knowledge of the functional versatility and dynamic nature of the ECM has improved the understanding of cancer biology. Translational Significance: This work provides an in-depth view of the importance of the ECM to develop more mimetic breast cancer models, which aim to recreate the components and architecture of tumor microenvironment. Special focus is placed on decellularized matrices derived from tissue and cell culture, both in procurement and applications, as they have achieved great success in cancer research and pharmaceutical sector. The extracellular matrix (ECM) is increasingly recognized as a master regulator of cell behavior and response to breast cancer (BC) treatment. During BC progression, the mammary gland ECM is remodeled and altered in the composition and organization. Accumulated evidence suggests that changes in the composition and mechanics of ECM, orchestrated by tumor-stromal interactions along with ECM remodeling enzymes, are actively involved in BC progression and metastasis. Understanding how specific ECM components modulate the tumorigenic process has led to an increased interest in the development of biomaterial-based biomimetic ECM models to recapitulate key tumor characteristics. The decellularized ECMs (dECMs) have emerged as a promising in vitro 3D tumor model, whose recent advances in the processing and application could become the biomaterial by excellence for BC research and the pharmaceutical industry. This review offers a detailed view of the contribution of ECM in BC progression, and highlights the application of dECM-based biomaterials as promising personalized tumor models that more accurately mimic the tumorigenic mechanisms of BC and the response to treatment. This will allow the design of targeted therapeutic approaches adapted to the specific characteristics of each tumor that will have a great impact on the precision medicine applied to BC patients.

Overview of MicroRNA Expression in Predicting Response to Neoadjuvant Therapies in Human Epidermal Growth Receptor-2 Enriched Breast Cancer - A Systematic Review

Purpose:

Increased appreciation of the human epidermal growth factor receptor-2 (HER2/neu) signalling pathway has led to the development of targeted therapeutic agents used in conjunction with chemotherapy to improve outcomes for HER2 overexpressing (HER2+) breast cancer. For neoadjuvant therapy, response rates can be unpredictable – novel biomarkers predicting effectiveness are required to enhance oncological outcomes for these patients, and microRNA may prove effective. Our objective was to identify microRNA (miRNA) expression patterns predictive of response to neoadjuvant chemotherapy (NAC) and/or anti-HER2 targeted therapies in patients being treated for early-stage HER2+ breast cancer.

Methods:

A search was performed of the PUBMED, SCOPUS, Web of Science, and EMBASE in accordance to Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines.

Results:

Overall, 15 studies including 1335 patients were included. These studies highlighted an expression profile of 73 miRNA and their ability to predict tumour response to neoadjuvant therapies was correlated. Results from 11 studies were in relation to circulatory miRNA and 4 studies included data from tumour tissue. Overall, upregulation and downregulation of 41 miRNA and 29 miRNA, respectively, predicted differential response to neoadjuvant therapy. Expression levels of 3 miRNA (miR-21, miR-210, and miR-376c-3p) were inconclusive in predicting therapeutic response, while ‘aberrant’ expression of circulating miR-199a predicted pathological complete response (pCR) to NAC.

Conclusions:

This systematic review outlines expression patterns of a number of miRNA which correlate with response to NAC and/or anti-HER2 therapies. Future translational research evaluating predictive biomarkers of primary response to neoadjuvant therapy in HER2+ breast cancer may consider these results.

The Metabolism Reprogramming of microRNA Let-7-Mediated Glycolysis Contributes to Autophagy and Tumor Progression

Cancer is usually a result of abnormal glucose uptake and imbalanced nutrient metabolization. The dysregulation of glucose metabolism, which controls the processes of glycolysis, gives rise to various physiological defects. Autophagy is one of the metabolic-related cellular functions and involves not only energy regeneration but also tumorigenesis. The dysregulation of autophagy impacts on the imbalance of metabolic homeostasis and leads to a variety of disorders. In particular, the microRNA (miRNA) Let-7 has been identified as related to glycolysis procedures such as tissue repair, stem cell-derived cardiomyocytes, and tumoral metastasis. In many cancers, the expression of glycolysis-related enzymes is correlated with Let-7, in which multiple enzymes are related to the regulation of the autophagy process. However, much recent research has not comprehensively investigated how Let-7 participates in glycolytic reprogramming or its links to autophagic regulations, mainly in tumor progression. Through an integrated literature review and omics-related profiling correlation, this review provides the possible linkage of the Let-7 network between glycolysis and autophagy, and its role in tumor progression.

The tumor microenvironment as driver of stemness and therapeutic resistance in breast cancer: New challenges and therapeutic opportunities

BACKGROUND

Breast cancer (BC), the second most common cause of cancer-related deaths, remains a significant threat to the health and wellness of women worldwide. The tumor microenvironment (TME), comprising cellular components, such as cancer-associated fibroblasts (CAFs), immune cells, endothelial cells and adipocytes, and noncellular components such as extracellular matrix (ECM), has been recognized as a critical contributor to the development and progression of BC. The interplay between TME components and cancer cells promotes phenotypic heterogeneity, cell plasticity and cancer cell stemness that impart tumor dormancy, enhanced invasion and metastasis, and the development of therapeutic resistance. While most previous studies have focused on targeting cancer cells with a dismal prognosis, novel therapies targeting stromal components are currently being evaluated in preclinical and clinical studies, and are already showing improved efficacies. As such, they may offer better means to eliminate the disease effectively.

CONCLUSIONS

In this review, we focus on the evolving concept of the TME as a key player regulating tumor growth, metastasis, stemness, and the development of therapeutic resistance. Despite significant advances over the last decade, several clinical trials focusing on the TME have failed to demonstrate promising effectiveness in cancer patients. To expedite clinical efficacy of TME-directed therapies, a deeper understanding of the TME is of utmost importance. Secondly, the efficacy of TME-directed therapies when used alone or in combination with chemo- or radiotherapy, and the tumor stage needs to be studied. Likewise, identifying molecular signatures and biomarkers indicating the type of TME will help in determining precise TME-directed therapies.

Polyphenol-Enriched Blueberry Preparation Controls Breast Cancer Stem Cells by Targeting FOXO1 and miR-145

Scientific evidence supports the early deregulation of epigenetic profiles during breast carcinogenesis. Research shows that cellular transformation, carcinogenesis, and stemness maintenance are regulated by epigenetic-specific changes that involve microRNAs (miRNAs). Dietary bioactive compounds such as blueberry polyphenols may modulate susceptibility to breast cancer by the modulation of CSC survival and self-renewal pathways through the epigenetic mechanism, including the regulation of miRNA expression. Therefore, the current study aimed to assay the effect of polyphenol enriched blueberry preparation (PEBP) or non-fermented blueberry juice (NBJ) on the modulation of miRNA signature and the target proteins associated with different clinical-pathological characteristics of breast cancer such as stemness, invasion, and chemoresistance using breast cancer cell lines. To this end, 4T1 and MB-MDM-231 cell lines were exposed to NBJ or PEBP for 24 h. miRNA profiling was performed in breast cancer cell cultures, and RT-qPCR was undertaken to assay the expression of target miRNA. The expression of target proteins was examined by Western blotting. Profiling of miRNA revealed that several miRNAs associated with different clinical-pathological characteristics were differentially expressed in cells treated with PEBP. The validation study showed significant downregulation of oncogenic miR-210 expression in both 4T1 and MDA-MB-231 cells exposed to PEBP. In addition, expression of tumor suppressor miR-145 was significantly increased in both cell lines treated with PEBP. Western blot analysis showed a significant increase in the relative expression of FOXO1 in 4T1 and MDA-MB-231 cells exposed to PEBP and in MDA-MB-231 cells exposed to NBJ. Furthermore, a significant decrease was observed in the relative expression of N-RAS in 4T1 and MDA-MB-231 cells exposed to PEBP and in MDA-MB-231 cells exposed to NBJ. Our data indicate a potential chemoprevention role of PEBP through the modulation of miRNA expression, particularly miR-210 and miR-145, and protection against breast cancer development and progression. Thus, PEBP may represent a source for novel chemopreventative agents against breast cancer.

Transcriptomic Analysis of Gene Networks Regulated by U11 Small Nuclear RNA in Bladder Cancer

Small nuclear RNA is a class of non-coding RNA that widely exist in the nucleus of eukaryotes. Accumulated evidences have shown that small nuclear RNAs are associated with the regulation of gene expression in various tumor types. To explore the gene expression changes and its potential effects mediated by U11 snRNA in bladder cancer cells, U11 snRNA knockout and overexpressed cell lines were constructed and further used to analyze the gene expression changes by RNA sequencing. The differentially expressed genes were found to be mainly enriched in tumor-related pathways both in the U11 knockout and overexpression cell lines, such as NF-kappa B signaling pathway, bladder cancer and PI3K-Akt signaling pathway. Furthermore, alternative splicing events were proposed to participate in the potential regulatory mechanism induced by the U11 knockout or overexpression. In conclusion, U11 may be involved in the regulation of gene expression in bladder cancer cells, which may provide a potentially new biomarker for clinical diagnosis and treatment of bladder cancer.

Upregulation of miR-138 Increases Sensitivity to Cisplatin in Hepatocellular Carcinoma by Regulating EZH2

Chemotherapeutic insensitivity is a major obstacle for effective treatment of hepatocellular carcinoma (HCC). Recently, new evidence showed that microRNAs (miRNAs) are closely related to drug sensitivity. This study aimed to investigate the relationship between miR-138 expression and cisplatin sensitivity of HCC cells by regulation of EZH2. CCK-8, EdU, and western blotting are determining the cell viability, proliferation, EZH2, and EMT-related protein expression. It was found that compared with normal samples, miR-138 expression was lower in cancer tissue; it was also downregulated in HCC cells. Transfected with miR-138 mimic increased sensitivity of HCC cells to cisplatin. Mechanistically, Luciferase Reporter analysis verified the interaction between miR-138 and target gene EZH2. Inhibition of EZH2 enhanced cisplatin sensitivity and transfection with EZH2 mimic mirrored the function of miR-138 in cisplatin sensitivity. Furthermore, the role of miR-138 on reversed cisplatin-induced epithelial–mesenchymal transition (EMT) was attenuated when combined with EZH2 plasmid. In conclusion, all data from this study illustrate that miR-138 may as a tumor suppressor provides a potential treatment method to treating HCC.

Bioinformatic gene analysis for potential biomarkers and therapeutic targets of diabetic nephropathy associated renal cell carcinoma

Background

Numerous epidemiological studies have confirmed that diabetes can promote the development of malignant tumors. However, the relationship between renal cell carcinoma (RCC) and diabetic nephropathy (DN) is still controversial. This study aimed to investigate the genes that are co-expressed in DN and RCC in order to gain a better understanding of the relationship between these diseases, and to identify potential biomarkers and targets for the treatment of DN-related RCC.

Methods

We evaluated the differentially expressed genes (DEGs) that are co-expressed in DN and RCC using a wide range of target prediction and analysis methods. Twenty-four genes were identified by intersecting the differential genes of 3 DN datasets and 2 RCC datasets. We predicted the micro-ribonucleic acids (miRNAs) of these genes that may be controlled using the miRNA Data Integration Portal (mirDIP) database, and rated them according to each data forecast based on the Comparative Toxicogenomics Database (CTD) and the StarBase database.

Results

Four genes were associated with DN and RCC patients: the predicted miRNAs hsa-miR-200b-3p and hsa-miR-429 of fibronectin 1 (FN1); the predicted miRNA hsa-miR-29c-3p of collagen type 1 alpha 2 (COL1A2); the predicted miRNA hsa-miR-29c-3p of collagen type 3 alpha 1 (COL3A1); and the predicted miRNA hsa-miR-29a-3p and hsa-miR-200c-3p of glucose-6-phosphatase catalytic subunit (G6PC). These genes may serve as potential biomarkers or specific targets in the treatment of DN-related RCC.

Conclusions

A significant correlation was identified between DN and RCC. The FN1, COL1A2, COL3A1, and G6PC genes could be novel biomarkers of DN-related RCC.

The anti-tumor effect of ursolic acid on papillary thyroid carcinoma via suppressing Fibronectin-1

This study aims to discover the effects of ursolic acid (UA) on papillary thyroid carcinoma (PTC). Human PTC cells were under UA treatment, and cell viability, clone formation, and apoptosis were measured by MTT assay, clone formation assay, and flow cytometry, respectively. Expressions of apoptosis- and epithelial-mesenchymal transition (EMT)-related markers were determined via qRT-PCR and western blot. Fibronectin-1 (FN1) expression in thyroid carcinoma was analyzed by GEPIA2 and qRT-PCR. The effects of overexpressed FN1 on UA-treated cells were detected following the previous procedures. Cell viability, proliferation, and EMT-related marker expressions were inhibited, while cell apoptosis and apoptosis-related marker expressions were promoted by UA. FN1 was higher expressed in thyroid carcinoma and downregulated by UA. Effects of FN1 on cell viability, proliferation, and apoptosis- and EMT-related marker expressions were partially reversed by UA. UA inhibited human PTC cell viability, proliferation, and EMT but promoted apoptosis via suppressing FN1.

Circulating miRNAs in HER2-Positive and Triple Negative Breast Cancers: Potential Biomarkers and Therapeutic Targets

Breast cancer is one of the most prevalent diseases among women worldwide and is highly associated with cancer-related mortality. Of the four major molecular subtypes, HER2-positive and triple-negative breast cancer (TNBC) comprise more than 30% of all breast cancers. While the HER2-positive subtype lacks estrogen and progesterone receptors and overexpresses HER2, the TNBC subtype lacks estrogen, progesterone and HER2 receptors. Although advances in molecular biology and genetics have substantially ameliorated breast cancer disease management, targeted therapies for the treatment of estrogen-receptor negative breast cancer patients are still restricted, particularly for TNBC. On the other hand, it has been demonstrated that microRNAs, miRNAs or small non-coding RNAs that regulate gene expression are involved in diverse biological processes, including carcinogenesis. Moreover, circulating miRNAs in serum/plasma are among the most promising diagnostic/therapeutic tools as they are stable and relatively easy to quantify. Various circulating miRNAs have been identified in several human cancers including specific breast cancer subtypes. This review aims to discuss the role of circulating miRNAs as potential diagnostic and prognostic biomarkers as well as therapeutic targets for estrogen-receptor negative breast cancers, HER2+ and triple negative.

Molecular mechanism of targeted inhibition of HMGA2 via miRNAlet-7a in proliferation and metastasis of laryngeal squamous cell carcinoma

MiRNAlet-7a is associated with the tumorigenesis of laryngeal squamous cell carcinoma (LSCC). Our study was designed to infer whether let-7a targets high-mobility AT-hook 2 (HMGA2) and suppresses laryngeal carcinoma cell proliferation, invasion, and migration. The expression levels of let-7a and HMGA2 were measured in 30 LSCC clinical specimens by qRT-PCR and their correlation was analyzed. Cell model and mice xenograft model with or without let-7a overexpression were constructed to evaluate the effects of let-7a on LSCC. Moreover, luciferase assay was performed to reveal the interaction between let-7a and HMGA2, which was further verified in xenograft. Let-7a was significantly down-regulated and HMGA2 was up-regulated in LSCC tissues compared with normal tissues (P<0.05), both of which were significantly correlated with TNM stage and lymph node metastases of LSCC patients (P<0.05). We also observed a negative correlation between let-7a and HMGA2 expression in LSCC samples (r = -0.642, P<0.05). In vitro and in vivo experiments demonstrated that let-7a overexpression could inhibit cell proliferation and tumor growth of LSCC and simultaneously down-regulate the expression of HMGA2. Moreover, the regulation of HMGA2 by let-7a was also proved by luciferase assay. Our results revealed that let-7a promotes development and progression of LSCC through inhibiting the expression of HMGA2. Therefore, let-7a may thus be a potential diagnostic biomarker and therapeutic target for treating LSCC.

SRY‑related HMG box‑2 role in anaplastic thyroid cancer aggressiveness is related to the fibronectin 1 and PI3K/AKT pathway

Anaplastic thyroid cancer (ATC) is a rare thyroid tumor associated with high mortality rates; thus, the identification of novel molecular targets and the development of therapeutic strategies are urgently required. The present study aimed to investigate the role of SRY-related HMG box-2 (SOX2) in ATC cells and explore whether the underlying mechanism was associated with fibronectin 1 (FN1). The proliferative, migratory and invasive ability of ATC cell lines was investigated using Cell Counting Kit-8, colony formation, wound-healing and Transwell assays, respectively; SOX2 expression in FRO cells was knocked down using small interfering RNA and SOX2 overexpression in FRO cells was achieved using cDNA constructs; and reverse transcription-quantitative PCR and western blotting were used to identify the mechanism of action underlying the SOX-2 mediated increased in cell aggressive phenotypes. Increased protein expression levels of SOX2 protein were observed in ATC tissue, and FRO and 8505c ATC cell lines. SOX2 overexpression increased the cell viability, and proliferative, migratory and invasive abilities of FRO cell lines. SOX2 overexpression increased FN1, p65, phosphorylated PI3K and AKT expression levels, whereas the knockdown of SOX2 promoted the opposite effects. In conclusion, the present study suggested a possible model of SOX2-mediated gene regulation in ATC cells, in which the overexpression of SOX2 promoted FN1 expression via the PI3K/AKT signaling pathway to induce the aggressive phenotype of ATC. These findings may provide crucial molecular insights into ATC pathogenesis and may demonstrate potential to develop into novel therapeutic interventions for patients with ATC.

The Tumor Microenvironment: Focus on Extracellular Matrix

The extracellular matrix (ECM) regulates the development and maintains tissue homeostasis. The ECM is composed of a complex network of molecules presenting distinct biochemical properties to regulate cell growth, survival, motility, and differentiation. Among their components, proteoglycans (PGs) are considered one of the main components of ECM. Its composition, biomechanics, and anisotropy are exquisitely tuned to reflect the physiological state of the tissue. The loss of ECM's homeostasis is seen as one of the hallmarks of cancer and, typically, defines transitional events in tumor progression and metastasis. In this chapter, we discuss the types of proteoglycans and their roles in cancer. It has been observed that the amount of some ECM components is increased, while others are decreased, depending on the type of tumor. However, both conditions corroborate with tumor progression and malignancy. Therefore, ECM components have an increasingly important role in carcinogenesis and this leads us to believe that their understanding may be a key in the discovery of new anti-tumor therapies. In this book, the main ECM components will be discussed in more detail in each chapter.

Long noncoding RNA lnc-ABCA12-3 promotes cell migration, invasion, and proliferation by regulating fibronectin 1 in esophageal squamous cell carcinoma

Long noncoding RNAs (lncRNAs) have been shown to play important roles in human cancers, including esophageal squamous cell carcinoma (ESCC). We previously demonstrated that a novel lncRNA, lnc-ABCA12-3, was overexpressed in ESCC tissues. However, the exact function of lnc-ABCA12-3 is unknown. In the current study, we aimed to evaluate the expression of lnc-ABCA12-3 in ESCC and to explore the potential mechanism of lnc-ABCA12-3 in cell migration, invasion, and proliferation. We showed that lnc-ABCA12-3 was upregulated in ESCC tumor tissues and cell lines. The increased expression of lnc-ABCA12-3 was positively associated with advanced tumor-node-metastasis stages and poor prognosis. The knockdown of lnc-ABCA12-3 inhibited the cell migration, invasion, and proliferation abilities of KYSE-510 and Eca-109 cells. We also found that fibronectin 1 (FN1) was upregulated in ESCC tumor tissues. The expression of FN1 messenger RNA was positively correlated with the expression of lnc-ABCA12-3 in ESCC tumor tissues. After lnc-ABCA12-3 knockdown, the expression of FN1 was downregulated. In addition, the overexpression of FN1 restored the abilities of cell migration, invasion and proliferation in Eca-109 cells. Further studies indicated that lnc-ABCA12-3 acted as a competing endogenous RNA for miR-200b-3p to regulate FN1 expression. In conclusion, these results suggest that lnc-ABCA12-3 is a novel oncogene in tumorigenesis and that its high expression is related to a poor prognosis for patients with ESCC. lnc-ABCA12-3 promotes cell migration, invasion, and proliferation via the regulation of FN1 in ESCC. Our data suggest that lnc-ABCA12-3 might serve as a potential prognostic biomarker and therapeutic target for ESCC.

Let-7 as biomarker, prognostic indicator, and therapy for precision medicine in cancer

Abnormal regulation and expression of microRNAs (miRNAs) has been documented in various diseases including cancer. The miRNA let-7 (MIRLET7) family controls developmental timing and differentiation. Let-7 loss contributes to carcinogenesis via an increase in its target oncogenes and stemness factors. Let-7 targets include genes regulating the cell cycle, cell signaling, and maintenance of differentiation. It is categorized as a tumor suppressor because it reduces cancer aggressiveness, chemoresistance, and radioresistance. However, in rare situations let-7 acts as an oncogene, increasing cancer migration, invasion, chemoresistance, and expression of genes associated with progression and metastasis. Here, we review let-7 function as tumor suppressor and oncogene, considering let-7 as a potential diagnostic and prognostic marker, and a therapeutic target for cancer treatment. We explain the complex regulation and function of different let-7 family members, pointing to abnormal processes involved in carcinogenesis. Let-7 is a promising option to complement conventional cancer therapy, but requires a tumor specific delivery method to avoid toxicity. While let-7 therapy is not yet established, we make the case that assessing its tumor presence is crucial when choosing therapy. Clinical data demonstrate that let-7 can be used as a biomarker for rational precision medicine decisions, resulting in improved patient survival.

Clinical correlation of opposing molecular signatures in head and neck squamous cell carcinoma

Background

The concept of head and neck cancers (HNSCC) having unique molecular signatures is well accepted but relating this to clinical presentation and disease behaviour is essential for patient benefit. Currently the clinical significance of HNSCC molecular subtypes is uncertain therefore personalisation of HNSCC treatment is not yet possible.

Methods

We performed meta-analysis on 8 microarray studies and identified six significantly up- (PLAU, FN1, CDCA5) and down-regulated (CRNN, CLEC3B and DUOX1) genes which were subsequently quantified by RT-qPCR in 100 HNSCC patient margin and core tumour samples.

Results

Retrospective correlation with sociodemographic and clinicopathological patient details identified two subgroups of opposing molecular signature (+q6 and -q6) that correlated to two recognised high-risk HNSCC populations in the UK. The +q6 group were older, male, and excessive alcohol users whilst the –q6 group were younger, female, paan-chewers and predominantly Bangladeshi. Additionally, all patients with tumour recurrence were in the latter subgroup.

Conclusions

We provide the first evidence linking distinct molecular signatures in HNSCC with clinical presentations. Prospective trials are required to determine the correlation between these distinct genotypes and disease progression or treatment response. This is an important step towards the ultimate goal of improving outcomes by utilising personalised molecular-signature-guided treatments for HNSCC patients.

Fibronectin promotes cervical cancer tumorigenesis through activating FAK signaling pathway

Cervical cancer is a cancer arising from the cervix, and it is the fourth most common cause of death in women. Overexpression of fibronectin 1 (FN1) was observed in many tumors and associated with the survival and metastasis of cancer cells. However, the mechanism by which FN1 promotes cervical cancer cell viability, migration, adhesion, and invasion, and inhibits cell apoptosis through focal adhesion kinase (FAK) signaling pathway remains to be investigated. Our results demonstrated that FN1 was upregulated in patients with cervical cancer and higher FN1 expression correlated with a poor prognosis for patients with cervical cancer. FN1 knockdown by small interfering RNA (siRNA) inhibited SiHa cell viability, migration, invasion, and adhesion, and promoted cell apoptosis. FN1 overexpression in CaSki cell promoted cell viability, migration, invasion, and adhesion, and inhibited cell apoptosis. Further, phosphorylation of FAK, a main downstream signaling molecule of FN1, and the protein expression of Bcl-2/Bax, matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9), and N-cadherin was upregulated in CaSki cells with FN1 overexpression, but caspase-3 protein expression was downregulated. The FAK phosphorylation inhibitor PF573228 inhibited FN1 overexpression-induced expression of those proteins in CaSki cells with FN1 overexpression. In vivo experiment demonstrated that FN1 knockdown significantly inhibited FN1 expression, phosphorylation of FAK, and tumor growth in xenograft from the nude mice. These results suggest that FN1 regulates the viability, apoptosis, migration, invasion, and adhesion of cervical cancer cells through the FAK signaling pathway and is a potential therapeutic target in the treatment of cervical cancer.

Amplification of hsa-miR-191/425 locus promotes breast cancer proliferation and metastasis by targeting DICER1

The dysregulation of micro RNAs (miRNAs) is a crucial characteristic of human cancers. Herein, we observed frequent amplification of the MIR191/425 locus in breast cancer, which is correlated with poor survival outcome. We demonstrated that the miR-191/425 cluster binds the 3' untranslated region of the DICER1 transcript and posttranscriptionally represses DICER1 expression, thereby impairing global miRNAs biogenesis. Functionally, the forced expression of miR-191 or miR-425 stimulated the proliferation, survival, migration and invasion of breast cancer cells, whereas the inhibition of miR-191 or miR-425 suppressed these oncogenic behaviors of breast cancer cells, in a manner dependent on miR-191/425-mediated downregulation of DICER1. Furthermore, the miR-191/425 cluster promoted breast tumor growth, invasion and metastasis in vivo. The let-7 family of miRNAs was downregulated upon forced expression of miR-191 or miR-425, with a corresponding increase in the levels of let-7 target, high-mobility group AT-hook 2 (HMGA2). The forced expression of let-7 partially abrogated the miR-191/425-mediated oncogenic effects in breast cancer cells, suggestive of let-7 as a downstream effector of the miR-191/425-DICER1 axis. Collectively, we proposed that the inhibition of global miRNA processing, through miR-191/425-mediated downregulation of DICER1, promotes breast cancer progression.

MiR-27a: A Novel Biomarker and Potential Therapeutic Target in Tumors

MicroRNAs (miRNAs) are endogenous, time sequencing, conserved and small non-coding RNA molecules (19-25 bp long) that regulate gene expression at the post-transcriptional level by binding to the partial sequence homology of the 3'-untranslated region of target messenger (m)RNA. The miRNA-27 family consists of miR-27a and miR-27b, which are transcribed from different chromosomes and different in nucleotide at the 3' end. It has been reported that miR-27a was located on chromosome 19 and played a vital role in tumor development. Increasing evidences support a vital role for miR-27a in modulating polymorphisms, tumorigenesis, proliferation, apoptosis, invasion, migration and angiogenesis. Apart from it, miR-27a could affect drug sensitivity, treatment of cancer and patients prognosis. The miR-27a could be an oncogene or a tumor suppressor in several types of cancer, including colon cancer, pancreatic cancer, breast cancer, bladder cancer and hepatocellular carcinoma. In this review, we discuss the role of miR-27a in tumor biology and clinical significance in detail and offer novel insights into molecular targeting therapy for human cancers.

Expression profile of Let-7s in peripheral blood mononuclear cells of normal and severe preeclampsia pregnant women

HEADINGS AIM

We aimed to investigate if the let-7 s expression level in the serum of peripheral blood from pregnant women with severe pre-eclampsia and normal pregnant women is related to the incidence of severe pre-eclampsia.

METHODS

Total RNA was extracted from collected peripheral blood mononuclear cells from 20 or over weeks pregnant women diagnosed with severe pre-eclampsia (age: 31.57 ± 4.94) and normal pregnant women (age: 29.75 ± 4.6) respectively, followed by real-time PCR to examine the expression of let-7 s. Correlation between let-7 s expression level and maternal age or body mass index of the normal pregnant women were also analyzed using SPSS21.0 software.

RESULTS

Let-7a and let-7 g were significantly increased in pregnant women with severe pre-eclampsia by 4.67 fold and 2.37 fold respectively compared to the normal pregnant women, whereas there was no significant difference in let-7b and let-7i. Moreover, there was no correlation between maternal age or body mass index and the expression level of let-7a, let-7b, let-7 g, and let-7i.

CONCLUSIONS

In conclusion, let-7a and let-7 g were significantly increased in the PBMCs of severe pre-eclampsia women compared to normal controls. Moreover, their expression level was not correlated to the maternal age or body mass of patients. Our data indicated that let-7a and let-7 g may be considered as predictive markers for SPE.

A genetic variant rs13293512 in the promoter of let-7 is associated with an increased risk of breast cancer in Chinese women

Growing evidence has demonstrated that single-nucleotide polymorphisms (SNPs) in the promoter of miRNA may influence individuals’ susceptibility to human diseases. We examined two SNPs rs10877887 and rs13293512 in the promoters of let-7 family to determine if the two SNPs were related to the occurrence of breast cancer (BC). Genotyping of the two SNPs was performed by PCR and restriction fragment length polymorphism analysis or TaqMan assay in 301 BC patients and 310 age matched controls. We found a higher frequency of rs13293512 CC genotype and rs13293512 C allele amongst BC patients (CC vs TT: adjusted odds ratio (OR) = 1.78; 95% CI: 1.14–2.80; P=0.012; C vs T: adjusted OR = 1.33; 95% CI: 1.06–1.67; P=0.013). Stratification analysis showed that rs13293512 CC genotype was associated with an increased risk of BC in patients with negative estrogen receptor (adjusted OR = 2.39; 95% CI: 1.32–4.30; P=0.004), patients with negative progesterone receptor (adjusted OR = 1.92; 95% CI: 1.11–3.33; P=0.02), patients with T1-2 stage cancer (adjusted OR = 1.77; 95% CI: 1.07–2.93; P=0.03), and patients with N1-3 stage cancer (adjusted OR = 1.89; 95% CI: 1.13–3.17; P=0.015). These findings suggest that rs13293512 in the promoter of let-7a-1/let-7f-1/let-7d cluster may be a possible biomarker for the development of BC in Chinese women.

Functional Effects of let-7g Expression in Colon Cancer Metastasis

MicroRNA regulation is crucial for gene expression and cell functions. It has been linked to tumorigenesis, development and metastasis in colorectal cancer (CRC). Recently, the let-7 family has been identified as a tumor suppressor in different types of cancers. However, the function of the let-7 family in CRC metastasis has not been fully investigated. Here, we focused on analyzing the role of let-7g in CRC. The Cancer Genome Atlas (TCGA) genomic datasets of CRC and detailed data from a Taiwanese CRC cohort were applied to study the expression pattern of let-7g. In addition, in vitro as well as in vivo studies have been performed to uncover the effects of let-7g on CRC. We found that the expression of let-7g was significantly lower in CRC specimens. Our results further supported the inhibitory effects of let-7g on CRC cell migration, invasion and extracellular calcium influx through store-operated calcium channels. We report a critical role for let-7g in the pathogenesis of CRC and suggest let-7g as a potential therapeutic target for CRC treatment.

HOXC6 promotes migration, invasion and proliferation of esophageal squamous cell carcinoma cells via modulating expression of genes involved in malignant phenotypes

Background

HOXC6 is a member of the HOX gene family. The elevated expression of this gene occurs in prostate and breast cancers. However, the role of HOXC6 in esophageal squamous cell carcinoma (ESCC) remains largely uninvestigated.

Methods

The expression of HOXC6 was examined by immunohistochemistry, quantitative real-time PCR and immunoblotting assays. The lentivirus-mediated expression of HOXC6 was verified at mRNA and protein levels. Wound healing and Matrigel assays were performed to assess the effect of HOXC6 on the migration and invasion of cancer cells. The growth curving, CCK8, and colony formation assays were utilized to access the proliferation capacities. RNA-seq was performed to evaluate the downstream targets of HOXC6. Bioinformatic tool was used to analyze the gene expression.

Results

HOXC6 was highly expressed in ESCC tissues. HOXC6 overexpression promoted the migration, invasion, and proliferation of both Eca109 and TE10 cells. There were 2,155 up-regulated and 759 down-regulated genes in Eca109-HOXC6 cells and 95 up-regulated and 47 down-regulated genes in TE10-HOXC6 cells compared with the results of control. Interestingly, there were only 20 common genes, including 17 up-regulated and three down-regulated genes with similar changes upon HOXC6 transfection in both cell lines. HOXC6 activated several crucial genes implicated in the malignant phenotype of cancer cells.

Discussion

HOXC6 is highly expressed in ESCC and promotes malignant phenotype of ESCC cells. HOXC6 can be used as a new therapeutic target of ESCC.

How does estrogen work on autophagy?

Macroautophagy/autophagy is vital for intracellular quality control and homeostasis. Therefore, careful regulation of autophagy is very important. In the past 10 years, a number of studies have reported that estrogenic effectors affect autophagy. However, some results, especially those regarding the modulatory effect of 17β-estradiol (E2) on autophagy seem inconsistent. Moreover, several clinical trials are already in place combining both autophagy inducers and autophagy inhibitors with endocrine therapies for breast cancer. Not all patients experience benefit, which further confuses and complicates our understanding of the main effects of autophagy in estrogen-related cancer. In view of the importance of the crosstalk between estrogen signaling and autophagy, this review summarizes the estrogenic effectors reported to affect autophagy, subcellular distribution and translocation of estrogen receptors, autophagy-targeted transcription factors (TFs), miRNAs, and histone modifications regulated by E2. Upon stimulation with estrogen, there will always be opposing functional actions, which might occur between different receptors, receptors on TFs, TFs on autophagy genes, or even histone modifications on transcription. The huge signaling network downstream of estrogen can promote autophagy and reduce overstimulated autophagy at the same time, which allows autophagy to be regulated by estrogen in a restricted range. To help understand how the estrogenic regulation of autophagy affects cell fate, a hypothetical model is presented here. Finally, we discuss some exciting new directions in the field. We hope this might help to better understand the multiple associations between estrogen and autophagy, the pathogenic mechanisms of many estrogen-related diseases, and to design novel and efficacious therapeutics. Abbreviations: AP-1, activator protein-1; HATs, histone acetyltransferases; HDAC, histone deacetylases; HOTAIR, HOX transcript antisense RNA.

A Five-MicroRNA Signature Predicts Survival and Disease Control of Patients with Head and Neck Cancer Negative for HPV Infection

PURPOSE

Human papillomavirus (HPV)-negative head and neck squamous cell carcinoma (HNSCC) is associated with unfavorable prognosis, while independent prognostic markers remain to be defined.

EXPERIMENTAL DESIGN

We retrospectively performed miRNA expression profiling. Patients were operated for locally advanced HPV-negative HNSCC and had received radiochemotherapy in eight different hospitals (DKTK-ROG; n = 85). Selection fulfilled comparable demographic, treatment, and follow-up characteristics. Findings were validated in an independent single-center patient sample (LMU-KKG; n = 77). A prognostic miRNA signature was developed for freedom from recurrence and tested for other endpoints. Recursive-partitioning analysis was performed on the miRNA signature, tumor and nodal stage, and extracapsular nodal spread. Technical validation used qRT-PCR. An miRNA-mRNA target network was generated and analyzed.

RESULTS

For DKTK-ROG and LMU-KKG patients, the median follow-up was 5.1 and 5.3 years, and the 5-year freedom from recurrence rate was 63.5% and 75.3%, respectively. A five-miRNA signature (hsa-let-7g-3p, hsa-miR-6508-5p, hsa-miR-210-5p, hsa-miR-4306, and hsa-miR-7161-3p) predicted freedom from recurrence in DKTK-ROG [hazard ratio (HR) 4.42; 95% confidence interval (CI), 1.98-9.88, P < 0.001], which was confirmed in LMU-KKG (HR 4.24; 95% CI, 1.40-12.81, P = 0.005). The signature also predicted overall survival (HR 3.03; 95% CI, 1.50-6.12, P = 0.001), recurrence-free survival (HR 3.16; 95% CI, 1.65-6.04, P < 0.001), and disease-specific survival (HR 5.12; 95% CI, 1.88-13.92, P < 0.001), all confirmed in LMU-KKG data. Adjustment for relevant covariates maintained the miRNA signature predicting all endpoints. Recursive-partitioning analysis of both samples combined classified patients into low (n = 17), low-intermediate (n = 80), high-intermediate (n = 48), or high risk (n = 17) for recurrence (P < 0.001).

CONCLUSIONS

The five-miRNA signature is a strong and independent prognostic factor for disease recurrence and survival of patients with HPV-negative HNSCC.See related commentary by Clump et al., p. 1441.

Identification of recurrence-associated microRNAs in stage I lung adenocarcinoma

Lung cancer is the most common cause of cancer-associated death worldwide. Postoperative relapse and subsequent metastasis result in a high mortality rate, even in early stage lung cancer. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the post-transcriptional level and are frequently dysregulated in various cancers. The aim of this study was to identify recurrence-associated miRNAs in early stage lung cancer. To screen for differentially expressed miRNAs related to postoperative recurrence, miRNA microarray data derived from stage I lung adenocarcinoma formalin-fixed paraffin-embedded (FFPE) tissue samples (n = 6) and publically available the Cancer Genome Atlas (TCGA) data were analyzed. An independent sample (n = 29) was used to validate candidate miRNAs by quantitative real-time polymerase chain reaction (qRT-PCR). In miRNA expression profiling, we identified 60 significantly dysregulated miRNAs in the relapsed group. Additionally, 20 dysregulated miRNAs were found using TCGA data set. Three miRNAs (let-7g-5p, miR-143-3p, and miR-374a-5p) were associated with postoperative recurrence in both microarray and TCGA data sets. All 3 candidate miRNAs were validated in the independent cohort of stage I adenocarcinoma by qRT-PCR. We discovered 3 recurrence-associated miRNAs of stage I lung adenocarcinoma samples using FFPE tissue, which showed possible clinical utility as biomarkers predicting recurrence after curative surgery. Further investigation of the functional properties of these miRNAs is needed.

Engineering Breast Cancer Microenvironments and 3D Bioprinting

The extracellular matrix (ECM) is a critical cue to direct tumorigenesis and metastasis. Although two-dimensional (2D) culture models have been widely employed to understand breast cancer microenvironments over the past several decades, the 2D models still exhibit limited success. Overwhelming evidence supports that three dimensional (3D), physiologically relevant culture models are required to better understand cancer progression and develop more effective treatment. Such platforms should include cancer-specific architectures, relevant physicochemical signals, stromal-cancer cell interactions, immune components, vascular components, and cell-ECM interactions found in patient tumors. This review briefly summarizes how cancer microenvironments (stromal component, cell-ECM interactions, and molecular modulators) are defined and what emerging technologies (perfusable scaffold, tumor stiffness, supporting cells within tumors and complex patterning) can be utilized to better mimic native-like breast cancer microenvironments. Furthermore, this review emphasizes biophysical properties that differ between primary tumor ECM and tissue sites of metastatic lesions with a focus on matrix modulation of cancer stem cells, providing a rationale for investigation of underexplored ECM proteins that could alter patient prognosis. To engineer breast cancer microenvironments, we categorized technologies into two groups: (1) biochemical factors modulating breast cancer cell-ECM interactions and (2) 3D bioprinting methods and its applications to model breast cancer microenvironments. Biochemical factors include matrix-associated proteins, soluble factors, ECMs, and synthetic biomaterials. For the application of 3D bioprinting, we discuss the transition of 2D patterning to 3D scaffolding with various bioprinting technologies to implement biophysical cues to model breast cancer microenvironments.

Non-coding RNAs in Various Stages of Liver Disease Leading to Hepatocellular Carcinoma: Differential Expression of miRNAs, piRNAs, lncRNAs, circRNAs, and sno/mt-RNAs

Hepatocellular carcinoma (HCC) was the fifth leading cause of cancer death in men and eighth leading cause of death in women in the United States in 2017. In our study, we sought to identify sncRNAs in various stages of development of HCC. We obtained publicly available small RNA-seq data derived from patients with cirrhosis (n = 14), low-grade dysplastic nodules (LGDN, n = 9), high grade dysplastic nodules (HGDN, n = 6), early hepatocellular carcinoma (eHCC, n = 6), and advanced hepatocellular carcinoma (HCC, n = 20), along with healthy liver tissue samples (n = 9). All samples were analyzed for various types of non-coding RNAs using PartekFlow software. We remapped small RNA-seq to miRBase to obtain differential expressions of miRNAs and found 87 in cirrhosis, 106 in LGDN, 59 in HGDN, 80 in eHCC, and 133 in HCC. Pathway analysis of miRNAs obtained from diseased samples compared to normal samples showed signaling pathways in the microRNA dependent EMT, CD44, and others. Additionally, we analyzed the data sets for piRNAs, lncRNAs, circRNAs, and sno/mt-RNAs. We validated the in silico data using human HCC samples with NanoString miRNA global expression. Our results suggest that publically available data is a valuable resource for sncRNA identification in HCC progression (FDR set to <0.05 for all samples) and that a data mining approach is useful for biomarker development.

Oncogenic mechanisms of Lin28 in breast cancer: new functions and therapeutic opportunities

The RNA binding protein Lin28 is best known for the critical role in cell development, recent researches also have implied its oncogenic function in various human cancers, including breast cancer. Specifically, aberrant Lin28 participates in multiple pathological processes, such as proliferation, metastasis, radiotherapy and chemotherapy resistance, metabolism, immunity and inflammation as well as stemness. In this review, we summarize the let-7-dependent and let-7-independent mechanism regulated by Lin28, focusing on its relation with tumor hallmarks in breast cancer, and subsequently discuss our present knowledge of Lin28 to develop a molecular-based therapeutic strategy against breast cancer.

ERβ-Mediated Alteration of circATP2B1 and miR-204-3p Signaling Promotes Invasion of Clear Cell Renal Cell Carcinoma

Early studies have indicated that estrogen receptor beta (ERβ) can influence the progression of clear cell renal cell carcinoma (ccRCC). Here, we report the mechanistic details of ERβ-mediated progression of ccRCC. ERβ increased ccRCC cell invasion via suppression of circular RNA ATP2B1 (circATP2B1) expression by binding directly to the 5' promoter region of its host gene ATPase plasma membrane Ca2⁺ transporting 1 (ATP2B1). ERβ-suppressed circATP2B1 then led to reduced miR-204-3p, which increased fibronectin 1 (FN1) expression and enhanced ccRCC cell invasion. Targeting ERβ with shRNA suppressed ccRCC metastasis in a murine model of RCC; adding circATP2B1 shRNA partly reversed this effect. Consistent with these experimental results, ccRCC patient survival data from The Cancer Genome Atlas indicated that a patient with higher ERβ and FN1 expression had worse overall survival and a patient with higher miR-204-3p expression had significantly better overall survival. Together, these results suggest that ERβ promotes ccRCC cell invasion by altering the ERβ/circATP2B1/miR-204-3p/FN1 axis and that therapeutic targeting of this newly identified pathway may better prevent ccRCC progression.Significance: These results identify an ERβ/circATP2B1/miR-204-3p/FN1 signaling axis in RCC, suggesting ERβ and circular RNA ATP2B1 as prognostic biomarkers for this disease. Cancer Res; 78(10); 2550-63. ©2018 AACR.

Let-7c inhibits cholangiocarcinoma growth but promotes tumor cell invasion and growth at extrahepatic sites

Cholangiocarcinoma (CCA) is a cancer type with high postoperative relapse rates and poor long-term survival largely due to tumor invasion, distant metastasis, and multidrug resistance. Deregulated microRNAs (miRNAs) are implicated in several cancer types including CCA. The specific roles of the miRNA let-7c in cholangiocarcinoma are not known and need to be further elucidated. In our translational study we show that microRNA let-7c expression was significantly downregulated in human cholangiocarcinoma tissues when compared to adjacent tissues of the same patient. Let-7c inhibited the tumorigenic properties of cholangiocarcinoma cells including their self-renewal capacity and sphere formation in vitro and subcutaneous cancer cell growth in vivo. Ectopic let-7c overexpression suppressed migration and invasion capacities of cholangiocarcinoma cell lines in vitro, however, promoted distant invasiveness in vivo. Furthermore, we found that let-7c regulated the aforementioned malignant biological properties, at least in part, through regulation of EZH2 protein expression and through the DVL3/β-catenin axis. The miRNA let-7c thus plays an important dual role in regulating tumorigenic and metastatic abilities of human cholangiocarcinoma through mechanisms involving EZH2 protein and the DVL3/β-catenin axis.

Let-7 microRNA controls invasion-promoting lysosomal changes via the oncogenic transcription factor myeloid zinc finger-1

Cancer cells utilize lysosomes for invasion and metastasis. Myeloid Zinc Finger1 (MZF1) is an ErbB2-responsive transcription factor that promotes invasion of breast cancer cells via upregulation of lysosomal cathepsins B and L. Here we identify let-7 microRNA, a well-known tumor suppressor in breast cancer, as a direct negative regulator of MZF1. Analysis of primary breast cancer tissues reveals a gradual upregulation of MZF1 from normal breast epithelium to invasive ductal carcinoma and a negative correlation between several let-7 family members and MZF1 mRNA, suggesting that the inverse regulatory relationship between let-7 and MZF1 may play a role in the development of invasive breast cancer. Furthermore, we show that MZF1 regulates lysosome trafficking in ErbB2-positive breast cancer cells. In line with this, MZF1 depletion or let-7 expression inhibits invasion-promoting anterograde trafficking of lysosomes and invasion of ErbB2-expressing MCF7 spheres. The results presented here link MZF1 and let-7 to lysosomal processes in ErbB2-positive breast cancer cells that in non-cancerous cells have primarily been connected to the transcription factor EB. Identifying MZF1 and let-7 as regulators of lysosome distribution in invasive breast cancer cells, uncouples cancer-associated, invasion-promoting lysosomal alterations from normal lysosomal functions and thus opens up new possibilities for the therapeutic targeting of cancer lysosomes.