TGF-beta switches from tumor suppressor to prometastatic factor in a model of breast cancer progression

TGFβ in malignant canine mammary tumors: relation with angiogenesis, immunologic markers and prognostic role

Transforming growth factor-β (TGFβ) and FoxP3 regulatory T cells (Treg) are involved in human breast carcinogenesis. This topic is not well documented in canine mammary tumors (CMT). In this work, the tumoral TGFβ expression was assessed by immunohistochemistry in 67 malignant CMT and its correlation to previously determined FoxP3, VEGF, and CD31 markers and other clinicopathologic parameters was evaluated. The high levels of TGFβ were statistically significantly associated with skin ulceration, tumor necrosis, high histological grade of malignancy (HGM), presence of neoplastic intravascular emboli and presence of lymph node metastases. The observed levels of TGFβ were positively correlated with intratumoral FoxP3 (strong correlation), VEGF (weak correlation) and CD31 (moderate correlation). Tumors that presented a concurrent high expression of TGFβ/FoxP3, TGFβ/VEGF, and TGFβ/CD31 markers were statistically significantly associated with parameters of tumor malignancy (high HGM, presence of vascular emboli and nodal metastasis). Additionally, shorter overall survival (OS) time was statistically significantly associated with tumors with an abundant TGFβ expression and with concurrent high expression of TGFβ/FoxP3, TGFβ/VEGF, and TGFβ/CD31. The presence of lymph node metastasis increased 11 times the risk of disease-related death, arising as an independent predictor of poor prognosis in the multivariable analysis. In conclusion, TGFβ and Treg cells seem involved in tumor progression emerging as potential therapeutic targets for future immunotherapy studies.

Inactivation of pentraxin 3 suppresses M2-like macrophage activity and immunosuppression in colon cancer

BACKGROUND

The tumor microenvironment is characterized by inflammation-like and immunosuppression situations. Although cancer-associated fibroblasts (CAFs) are among the major stromal cell types in various solid cancers, including colon cancer, the interactions between CAFs and immune cells remains largely uncharacterized. Pentraxin 3 (PTX3) is responsive to proinflammatory cytokines and modulates immunity and tissue remodeling, but its involvement in tumor progression appears to be context-dependent and is unclear.

METHODS

Open-access databases were utilized to examine the association of PTX3 expression and the fibroblast signature in colon cancer. Loss-of-function assays, including studies in tamoxifen-induced Ptx3 knockout mice and treatment with an anti-PTX3 neutralizing antibody (WHC-001), were conducted to assess the involvement of PTX3 in colon cancer progression as well as its immunosuppressive effect. Finally, bioinformatic analyses and in vitro assays were performed to reveal the downstream effectors and decipher the involvement of the CREB1/CEBPB axis in response to PTX3 and PTX3-induced promotion of M2 macrophage polarization.

RESULTS

Clinically, higher PTX3 expression was positively correlated with fibroblasts and inflammatory response signatures and associated with a poor survival outcome in colon cancer patients. Blockade of PTX3 significantly reduced stromal cell-mediated tumor development. The decrease of the M2 macrophage population and an increase of the cytotoxic CD8+ T-cell population were observed following PTX3 inactivation in allografted colon tumors. We further revealed that activation of cyclic AMP-responsive element-binding protein 1 (CREB1) mediated the PTX3-induced promotion of M2 macrophage polarization.

CONCLUSIONS

PTX3 contributes to stromal cell-mediated protumor immunity by increasing M2-like macrophage polarization, and inhibition of PTX3 with WHC-001 is a potential therapeutic strategy for colon cancer.

Dynamics of transforming growth factor β signaling and therapeutic efficacy

Transforming growth factor β (TGFβ) is a multifunctional cytokine, and its signalling responses are exerted via integrated intracellular pathways and complex regulatory mechanisms. Due to its high potency, TGFβ signalling is tightly controlled under normal circumstances, while its dysregulation in cancer favours metastasis. The recognised potential of TGFβ as a therapeutic target led to emerging development of anti-TGFβ reagents with preclinical success, yet these therapeutics failed to recapitulate their efficacy in experimental settings. In this review, possible reasons for this inconsistency are discussed, addressing the knowledge gap between theoretical and actual behaviours of TGFβ signalling. Previous studies on oncogenic cells have demonstrated the spatiotemporal heterogeneity of TGFβ signalling intensity. Under feedback mechanisms and exosomal ligand recycling, cancer cells may achieve cyclic TGFβ signalling to facilitate dissemination and colonisation. This challenges the current presumption of persistently high TGFβ signalling in cancer, pointing to a new direction of research on TGFβ-targeted therapeutics.

Mutations involving TGFB and MAPK may be associated with malignancy in granular cell tumors

Granular cell tumors (GrCTs) are mesenchymal neoplasms of presumed schwannian differentiation that may present as solitary or multifocal lesions with excision usually being curative. A minority of cases, however, show histological features associated with an increased risk for metastasis and are highly aggressive leading to death in about a third of cases. While benign and malignant cases have been shown to harbor mutations in the H + ATPase genes, there is only limited data examining molecular aberrations associated with malignancy. The departmental archives were searched for cases of atypical/malignant GrCTs. Clinical and histopathological features were noted. Whole-exome sequencing was performed. Three cases of malignant GrCTs and one case of atypical GrCTs were included. All three malignant tumors metastasized to distant sites with a median disease-free survival of 16 months and an overall follow-up time of 35 months. Whole-exome sequencing showed mutations involving TGFβ and MAPK pathways in all four tumors. Although the cohort size is small, our preliminary findings suggest that mutations involving the TGFβ and MAPK pathways may be associated with tumor progression or malignant transformation in GrCT pathogenesis.

New roles for AP-1/JUNB in cell cycle control and tumorigenic cell invasion via regulation of cyclin E1 and TGF-β2

BACKGROUND

JUNB transcription factor contributes to the formation of the ubiquitous transcriptional complex AP-1 involved in the control of many physiological and disease-associated functions. The roles of JUNB in the control of cell division and tumorigenic processes are acknowledged but still unclear.

RESULTS

Here, we report the results of combined transcriptomic, genomic, and functional studies showing that JUNB promotes cell cycle progression via induction of cyclin E1 and repression of transforming growth factor (TGF)-β2 genes. We also show that high levels of JUNB switch the response of TGF-β2 stimulation from an antiproliferative to a pro-invasive one, induce endogenous TGF-β2 production by promoting TGF-β2 mRNA translation, and enhance tumor growth and metastasis in mice. Moreover, tumor genomic data indicate that JUNB amplification associates with poor prognosis in breast and ovarian cancer patients.

CONCLUSIONS

Our results reveal novel functions for JUNB in cell proliferation and tumor aggressiveness through regulation of cyclin E1 and TGF-β2 expression, which might be exploited for cancer prognosis and therapy.

A MYC-ZNF148-ID1/3 regulatory axis modulating cancer stem cell traits in aggressive breast cancer

The MYC proto-oncogene (MYC) is one of the most frequently overexpressed genes in breast cancer that drives cancer stem cell-like traits, resulting in aggressive disease progression and poor prognosis. In this study, we identified zinc finger transcription factor 148 (ZNF148, also called Zfp148 and ZBP-89) as a direct target of MYC. ZNF148 suppressed cell proliferation and migration and was transcriptionally repressed by MYC in breast cancer. Depletion of ZNF148 by short hairpin RNA (shRNA) and CRISPR/Cas9 increased triple-negative breast cancer (TNBC) cell proliferation and migration. Global transcriptome and chromatin occupancy analyses of ZNF148 revealed a central role in inhibiting cancer cell de-differentiation and migration. Mechanistically, we identified the Inhibitor of DNA binding 1 and 3 (ID1, ID3), drivers of cancer stemness and plasticity, as previously uncharacterized targets of transcriptional repression by ZNF148. Silencing of ZNF148 increased the stemness and tumorigenicity in TNBC cells. These findings uncover a previously unknown tumor suppressor role for ZNF148, and a transcriptional regulatory circuitry encompassing MYC, ZNF148, and ID1/3 in driving cancer stem cell traits in aggressive breast cancer.

Inflammatory Breast Cancer: The Secretome of HCMV+ Tumor-Associated Macrophages Enhances Proliferation, Invasion, Colony Formation, and Expression of Cancer Stem Cell Markers

Inflammatory breast cancer (IBC) is a highly aggressive phenotype of breast cancer that is characterized by a high incidence early metastasis. We previously reported a significant association of human cytomegalovirus (HCMV) DNA in the carcinoma tissues of IBC patients but not in the adjacent normal tissues. HCMV-infected macrophages serve as “mobile vectors” for spreading and disseminating virus to different organs, and IBC cancer tissues are highly infiltrated by tumor-associated macrophages (TAMs) that enhance IBC progression and promote breast cancer stem cell (BCSC)-like properties. Therefore, there is a need to understand the role of HCMV-infected TAMs in IBC progression. The present study aimed to test the effect of the secretome (cytokines and secreted factors) of TAMs derived from HCMV⁺ monocytes isolated from IBC specimens on the proliferation, invasion, and BCSC abundance when tested on the IBC cell line SUM149. HCMV⁺ monocytes were isolated from IBC patients during modified radical mastectomy surgery and tested in vitro for polarization into TAMs using the secretome of SUM149 cells. MTT, clonogenic, invasion, real-time PCR arrays, PathScan Intracellular Signaling array, and cytokine arrays were used to characterize the secretome of HCMV⁺ TAMs for their effect on the progression of SUM149 cells. The results showed that the secretome of HCMV⁺ TAMs expressed high levels of IL-6, IL-8, and MCP-1 cytokines compared to HCMV^- TAMs. In addition, the secretome of HCMV⁺ TAMs induced the proliferation, invasion, colony formation, and expression of BCSC-related genes in SUM149 cells compared to mock untreated cells. In addition, the secretome of HCMV⁺ TAMs activated the phosphorylation of intracellular signaling molecules p-STAT3, p-AMPKα, p-PRAS40, and p-SAPK/JNK in SUM149 cells. In conclusion, this study shows that the secretome of HCMV⁺ TAMs enhances the proliferation, invasion, colony formation, and BCSC properties by activating the phosphorylation of p-STAT3, p-AMPKα, p-PRAS40, and p-SAPK/JNK intracellular signaling molecules in IBC cells.

Oncogenic Pathways in Neurodegenerative Diseases

Cancer and neurodegenerative diseases are two of the leading causes of premature death in modern societies. Their incidence continues to increase, and in the near future, it is believed that cancer will kill more than 20 million people per year, and neurodegenerative diseases, due to the aging of the world population, will double their prevalence. The onset and the progression of both diseases are defined by dysregulation of the same molecular signaling pathways. However, whereas in cancer, these alterations lead to cell survival and proliferation, neurodegenerative diseases trigger cell death and apoptosis. The study of the mechanisms underlying these opposite final responses to the same molecular trigger is key to providing a better understanding of the diseases and finding more accurate treatments. Here, we review the ten most common signaling pathways altered in cancer and analyze them in the context of different neurodegenerative diseases such as Alzheimer's (AD), Parkinson's (PD), and Huntington's (HD) diseases.

Therapeutic Potential of Thymoquinone in Triple-Negative Breast Cancer Prevention and Progression through the Modulation of the Tumor Microenvironment

To date, the tumor microenvironment (TME) has gained considerable attention in various areas of cancer research due to its role in driving a loss of immune surveillance and enabling rapid advanced tumor development and progression. The TME plays an integral role in driving advanced aggressive breast cancers, including triple-negative breast cancer (TNBC), a pivotal mediator for tumor cells to communicate with the surrounding cells via lymphatic and circulatory systems. Furthermore, the TME plays a significant role in all steps and stages of carcinogenesis by promoting and stimulating uncontrolled cell proliferation and protecting tumor cells from the immune system. Various cellular components of the TME work together to drive cancer processes, some of which include tumor-associated adipocytes, fibroblasts, macrophages, and neutrophils which sustain perpetual amplification and release of pro-inflammatory molecules such as cytokines. Thymoquinone (TQ), a natural chemical component from black cumin seed, is widely used traditionally and now in clinical trials for the treatment/prevention of multiple types of cancer, showing a potential to mitigate components of TME at various stages by various pathways. In this review, we focus on the role of TME in TNBC cancer progression and the effect of TQ on the TME, emphasizing their anticipated role in the prevention and treatment of TNBC. It was concluded from this review that the multiple components of the TME serve as a critical part of TNBC tumor promotion and stimulation of uncontrolled cell proliferation. Meanwhile, TQ could be a crucial compound in the prevention and progression of TNBC therapy through the modulation of the TME.

Positive Association of Matrix Proteins Alteration with TAZ and The Progression of High-Grade Bladder Cancer

Objective

Bladder cancer is the 9^th cause of human urologic malignancy and the 13^th of death worldwide. Increased collagen cross-linking, NIDOGEN1 expression and consequently stiffness of extracellular matrix (ECM) may be responsible for the mechanotransduction and regulation of transcriptional co-activator with PDZ-binding motif (TAZ) and transforming growth factor β1 (TGF-β1) signaling pathways, resulting in progression of tumorigenesis. The present study aimed to assess whether type 1 collagen expression is associated with TAZ nuclear localization.

Materials and Methods

In this case-control study, real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemical analysis were performed to evaluate the activation of the TAZ pathway in patients with bladder cancer (n=40) and healthy individuals (n=20). The ELISA method was also conducted to measure the serum concentrations of TGF-β1. Masson’s trichrome staining was carried out to histologically evaluate the density of type 1 collagen.

Results

Our findings that the expression levels of COL1A1, COL1A2, NIDOGEN1, TAZ, and TGF-β1 genes were overexpressed in patients with bladder cancer, and their expression levels were positively associated with the grade of bladder cancer. The immunohistochemical analysis demonstrated that the nuclear localization of TAZ was markedly correlated with high-grade bladder cancer. We also found that TAZ nuclear localization was substantially higher in cancerous tissues as compared with normal bladder tissues. Masson's trichrome staining showed that the tissue density of type I collagen was considerably increased in patients with bladder cancer as compared with healthy subjects.

Conclusion

According to our findings, it seems the alterations in the expression of type I collagen and NIDOGEN1, as well as TAZ nuclear localization influence the progression of bladder cancer. The significance of TGF-β1 and TAZ expression in tumorigenesis and progression to high-grade bladder cancer was also highlighted. However, a possible relationship between TGF-β1 expression and the Hippo pathway needs further investigations.

Image-based high-throughput mapping of TGF-β-induced phosphocomplexes at a single-cell level

Protein interactions and posttranslational modifications orchestrate cellular responses to e.g. cytokines and drugs, but it has been difficult to monitor these dynamic events in high-throughput. Here, we describe a semi-automated system for large-scale in situ proximity ligation assays (isPLA), combining isPLA in microtiter wells with automated microscopy and computer-based image analysis. Phosphorylations and interactions are digitally recorded along with subcellular morphological features. We investigated TGF-β-responsive Smad2 linker phosphorylations and complex formations over time and across millions of individual cells, and we relate these events to cell cycle progression and local cell crowding via measurements of DNA content and nuclear size of individual cells, and of their relative positions. We illustrate the suitability of this protocol to screen for drug effects using phosphatase inhibitors. Our approach expands the scope for image-based single cell analyses by combining observations of protein interactions and modifications with morphological details of individual cells at high throughput.

To improve our ability to monitor cellular responses to e.g. cytokines or drugs, Lönn et al have developed a semi-automated system for large-scale in situ proximity ligation assays (isPLA) in HaCAT keratinocyte cells. Their approach expands the scope for image-based single cell analyses by combining observations of protein interactions and modifications with morphological details of individual cells at high throughput.

Therapeutically Targeting Cancers That Overexpress FOXC1: A Transcriptional Driver of Cell Plasticity, Partial EMT, and Cancer Metastasis

Metastasis accounts for more than 90% of cancer related mortality, thus the most pressing need in the field of oncology today is the ability to accurately predict future onset of metastatic disease, ideally at the time of initial diagnosis. As opposed to current practice, what would be desirable is that prognostic, biomarker-based detection of metastatic propensity and heightened risk of cancer recurrence be performed long before overt metastasis has set in. Without such timely information it will be impossible to formulate a rational therapeutic treatment plan to favorably alter the trajectory of disease progression. In order to help inform rational selection of targeted therapeutics, any recurrence/metastasis risk prediction strategy must occur with the paired identification of novel prognostic biomarkers and their underlying molecular regulatory mechanisms that help drive cancer recurrence/metastasis (i.e. recurrence biomarkers). Traditional clinical factors alone (such as TNM staging criteria) are no longer adequately prognostic for this purpose in the current molecular era. FOXC1 is a pivotal transcription factor that has been functionally implicated to drive cancer metastasis and has been demonstrated to be an independent predictor of heightened metastatic risk, at the time of initial diagnosis. In this review, we present our viewpoints on the master regulatory role that FOXC1 plays in mediating cancer stem cell traits that include cellular plasticity, partial EMT, treatment resistance, cancer invasion and cancer migration during cancer progression and metastasis. We also highlight potential therapeutic strategies to target cancers that are, or have evolved to become, “transcriptionally addicted” to FOXC1. The potential role of FOXC1 expression status in predicting the efficacy of these identified therapeutic approaches merits evaluation in clinical trials.

The Multifaceted Role of TGF-β in Gastrointestinal Tumors

Simple Summary

The transforming growth factor β signaling pathway elicits a broad range of physiological re-sponses, and its misregulation has been related to cancer. The secreted cytokine TGFβ exerts a tumor-suppressive effect that counteracts malignant transformation. However, once tumor has developed, TGFβ can support tumor progression regulating epithelial to mesenchymal transition, invasion and metastasis, stimulating fibrosis, angiogenesis and immune suppression. Here we review the dichotomous role of TGF-β in the progression of gastrointestinal tumors, as well as its intricate crosstalk with other signaling pathways. We also discuss about the therapeutic strate-gies that are currently explored in clinical trials to counteract TGF-β functions.

Abstract

Transforming growth factor-beta (TGF-β) is a secreted cytokine that signals via serine/threonine kinase receptors and SMAD effectors. Although TGF-β acts as a tumor suppressor during the early stages of tumorigenesis, it supports tumor progression in advanced stages. Indeed, TGF-β can modulate the tumor microenvironment by modifying the extracellular matrix and by sustaining a paracrine interaction between neighboring cells. Due to its critical role in cancer development and progression, a wide range of molecules targeting the TGF-β signaling pathway are currently under active clinical development in different diseases. Here, we focused on the role of TGF-β in modulating different pathological processes with a particular emphasis on gastrointestinal tumors.

N-cadherin mediates the migration of bone marrow-derived mesenchymal stem cells toward breast tumor cells

Rationale: Bone marrow-derived mesenchymal stem cells (BM-MSCs) recruited into breast tumors regulate the behavior of tumor cells via various mechanisms and affect clinical outcomes. Although signaling molecules, such as transforming growth factor β (TGF-β), are known to transmit signals between BM-MSCs and breast tumor cells for recruiting BM-MSCs, it is unclear which specific intrinsic molecules involved in cell motility mediate the migration of BM-MSCs into breast tumor. It is also unclear as to how specific intrinsic molecules contribute to the migration. Methods: Conditioned medium (CM) from breast tumor cells (MCF-7 and MDA-MB-231) that simulates breast tumor secreting TGF-β was used to examine the migration of BM-MSCs into breast tumors. A three-dimensional migration assay was performed to investigate the collective migration of BM-MSCs, maintaining cell-cell adhesion, toward breast tumor cells. Results: N-cadherin formed adherens junction-like structures on the intercellular borders of BM-MSCs, and TGF-β increased the expression of N-cadherin on these borders. Knockdown of Smad4 impaired the TGF-β-mediated increase in N-cadherin expression in BM-MSCs, but inhibitors of non-canonical TGF-β pathways, such as extracellular signal-regulated kinases, Akt, and p38, did not affect it. siRNA-mediated knockdown of N-cadherin and Smad4 impaired the migration of BM-MSCs in response to TGF-β. Conditioned medium from breast tumor cells also enhanced the expression of N-cadherin in BM-MSCs, but inactivation of TGF-β type 1 receptor (TGFBR1) with SB505124 and TGFBR1 knockdown abolished the increase in N-cadherin expression. BM-MSCs collectively migrated toward CM from MDA-MB-231 in vitro while maintaining cell-cell adhesion through N-cadherin. Knockdown of N-cadherin abolished the migration of BM-MSCs toward the CM from breast tumor cells. Conclusion: In the present study, we identified N-cadherin, an intrinsic transmembrane molecule in adherens junction-like structures, on BM-MSCs as a mediator for the migration of these cells toward breast tumor. The expression of N-cadherin increases on the intercellular borders of BM-MSCs through the TGF-β canonical signaling and they collectively migrate in response to breast tumor cells expressing TGF-β via N-cadherin-dependent cell-cell adhesion. We, herein, introduce a novel promising strategy for controlling and re-engineering the breast tumor microenvironment.

Targeting transforming growth factor-β signaling for enhanced cancer chemotherapy

During the past decades, drugs targeting transforming growth factor-β (TGFβ) signaling have received tremendous attention for late-stage cancer treatment since TGFβ signaling has been recognized as a prime driver for tumor progression and metastasis. Nonetheless, in healthy and pre-malignant tissues, TGFβ functions as a potent tumor suppressor. Furthermore, TGFβ signaling plays a key role in normal development and homeostasis by regulating cell proliferation, differentiation, migration, apoptosis, and immune evasion, and by suppressing tumor-associated inflammation. Therefore, targeting TGFβ signaling for cancer therapy is challenging. Recently, we and others showed that blocking TGFβ signaling increased chemotherapy efficacy, particularly for nanomedicines. In this review, we briefly introduce the TGFβ signaling pathway, and the multifaceted functions of TGFβ signaling in cancer, including regulating the tumor microenvironment (TME) and the behavior of cancer cells. We also summarize TGFβ targeting agents. Then, we highlight TGFβ inhibition strategies to restore the extracellular matrix (ECM), regulate the tumor vasculature, reverse epithelial-mesenchymal transition (EMT), and impair the stemness of cancer stem-like cells (CSCs) to enhance cancer chemotherapy efficacy. Finally, the current challenges and future opportunities in targeting TGFβ signaling for cancer therapy are discussed.

OSR1 phosphorylates the Smad2/3 linker region and induces TGF-β1 autocrine to promote EMT and metastasis in breast cancer

Oxidative stress-responsive kinase 1 (OSR1) plays a critical role in multiple carcinogenic signal pathways, and its overexpression has been found in various types of cancer; however, the pathophysiological role of OSR1 in breast cancer has not been evaluated. This study aims to elaborate on the role of OSR1 in breast cancer metastasis and the specific regulatory mechanism. Our results showed that OSR1 mRNA and protein were upregulated in both human breast cancer samples and cell lines. Moreover, phosphorylated OSR1 (p-OSR1) was an independent poor prognostic indicator in patients with breast cancer. OSR1 upregulation induced epithelial-to-mesenchymal transition (EMT) in normal and malignant mammary epithelial cells with the increasing metastatic capacity. In contrast, deleting OSR1 in aggressive breast cancer cells inhibited these phenotypes. OSR1 is the critical activator for transcription factors of EMT. Mechanistically, we found that OSR1 can directly interact and phosphorylate the linker region of Smad2 at Thr220 and Smad3 at Thr179. Phosphorylated Smad2/3 translocated into the nucleus to enhance transforming growth factor-β1 (TGF-β1) autocrine signalling and increase the transcription of EMT regulators. Importantly, interruption of the OSR1-Smad2/3-TGF-β1 signalling axis elicited a robust anti-EMT and anti-metastatic effect in vitro and in vivo. Taken together, we conclude that OSR1-mediated Smad2/3-TGF-β1 signalling promotes EMT and metastasis representing a promising therapeutic target in breast cancer treatment.

Proliferation-associated long noncoding RNA, TMPO-AS1, is a potential therapeutic target for triple-negative breast cancer

Triple‐negative breast cancer (TNBC) is an aggressive subtype of breast cancer compared with luminal or epidermal growth factor receptor 2 subtypes, thus effective therapeutic options for TNBC are yet to be developed. Nowadays, oncogenic long noncoding RNAs (lncRNAs) are applied to cancer management as a new class of therapeutic targets. We previously showed that thymopoietin antisense transcript 1 (TMPO‐AS1) is a proliferation‐associated lncRNA that contributes to hormone‐dependent breast cancer progression by stabilizing estrogen receptor‐α mRNA. We here showed that TMPO‐AS1 is abundantly expressed in basal‐like breast cancer subtype based on the transcriptomic data in The Cancer Genome Atlas as well as in TNBC cell lines and patient‐derived cells. Small interfering RNA‐based loss‐of‐function analyses showed that TMPO‐AS1 knockdown substantially represses the proliferation and migration of TNBC cells. Expression microarray analysis showed that TMPO‐AS1 alters gene signatures related to transforming growth factor‐β signaling in addition to proliferative E2F signaling pathways. TMPO‐AS1‐targeted siRNA treatment through engineered drug delivery systems using cancer‐targeted polyion complex micelle or nanoball technology significantly impaired the in vivo growth of primary and metastatic TNBC xenograft tumors. Our findings suggest that TMPO‐AS1 plays a key role in TNBC pathophysiology and could be a potential therapeutic target for TNBC.

Functional role of WW domain-containing proteins in tumor biology and diseases: Insight into the role in ubiquitin-proteasome system

The ubiquitin-proteasome system (UPS) governs the protein degradation process and balances proteostasis and cellular homeostasis. It is a well-controlled mechanism, in which removal of the damaged or excessive proteins is essential in driving signal pathways for cell survival or death. Accumulation of damaged proteins and failure in removal may contribute to disease initiation such as in cancers and neurodegenerative diseases. In this notion, specific protein-protein interaction is essential for the recognition of targeted proteins in UPS. WW domain plays an indispensable role in the protein-protein interactions during signaling. Among the 51 WW domain-containing proteins in the human proteomics, near one-quarter of them are involved in the UPS, suggesting that WW domains are crucial modules for driving the protein-protein binding and subsequent ubiquitination and degradation. In this review, we detail a broad spectrum of WW domains in protein-protein recognition, signal transduction, and relevance to diseases. New perspectives in dissecting the molecular interactions are provided.

Antisense Oligonucleotide in LNA-Gapmer Design Targeting TGFBR2-A Key Single Gene Target for Safe and Effective Inhibition of TGFβ Signaling

Antisense Oligonucleotides (ASOs) are an emerging drug class in gene modification. In our study we developed a safe, stable, and effective ASO drug candidate in locked nucleic acid (LNA)-gapmer design, targeting TGFβ receptor II (TGFBR2) mRNA. Discovery was performed as a process using state-of-the-art library development and screening. We intended to identify a drug candidate optimized for clinical development, therefore human specificity and gymnotic delivery were favored by design. A staggered process was implemented spanning in-silico-design, in-vitro transfection, and in-vitro gymnotic delivery of small batch syntheses. Primary in-vitro and in-vivo toxicity studies and modification of pre-lead candidates were also part of this selection process. The resulting lead compound NVP-13 unites human specificity and highest efficacy with lowest toxicity. We particularly focused at attenuation of TGFβ signaling, addressing both safety and efficacy. Hence, developing a treatment to potentially recondition numerous pathological processes mediated by elevated TGFβ signaling, we have chosen to create our data in human lung cell lines and human neuronal stem cell lines, each representative for prospective drug developments in pulmonary fibrosis and neurodegeneration. We show that TGFBR2 mRNA as a single gene target for NVP-13 responds well, and that it bears great potential to be safe and efficient in TGFβ signaling related disorders.

Targeting antisense mitochondrial noncoding RNAs induces bladder cancer cell death and inhibition of tumor growth through reduction of survival and invasion factors

Knockdown of the antisense noncoding mitochondrial RNAs (ASncmtRNAs) induces apoptotic death of several human tumor cell lines, but not normal cells, supporting a selective therapy against different types of cancer. In this work, we evaluated the effects of knockdown of ASncmtRNAs on bladder cancer (BCa). We transfected the BCa cell lines UMUC-3, RT4 and T24 with the specific antisense oligonucleotide Andes-1537S, targeted to the human ASncmtRNAs. Knockdown induced a strong inhibition of cell proliferation and increase in cell death in all three cell lines. As observed in UMUC-3 cells, the treatment triggered apoptosis, evidenced by loss of mitochondrial membrane potential and Annexin V staining, along with activation of procaspase-3 and downregulation of the anti-apoptotic factors survivin and Bcl-xL. Treatment also inhibited cell invasion and spheroid formation together with inhibition of N-cadherin and MMP 11. In vivo treatment of subcutaneous xenograft UMUC-3 tumors in NOD/SCID mice with Andes-1537S induced inhibition of tumor growth as compared to saline control. Similarly, treatment of a high-grade bladder cancer PDX with Andes-1537S resulted in a strong inhibition of tumor growth. Our results suggest that ASncmtRNAs could be potent targets for bladder cancer as adjuvant therapy.

A Review of the Potential Role of Human Cytomegalovirus (HCMV) Infections in Breast Cancer Carcinogenesis and Abnormal Immunity

Previously recognized classical human onco-viruses can regulate complex neoplastic events, and are estimated to play a role during carcinogenesis in 15-20% of cancer cases. Although the DNA and gene products of several viruses have been found in breast tumors, none of the classical onco-viruses have definitely been linked to the initiation of breast cancer. However, recent evidence shows that human cytomegalovirus (HCMV) gene products are found in >90% of tumors and metastases of breast cancers, and their increased expression can be correlated to a more aggressive breast cancer phenotype. Supporting the active role of HCMV in breast cancer, a specific HCMV strain, HCMV-DB, was recently shown to exert oncogenic transformational activity in breast epithelial cells in vitro, and to give rise to fast-growing, triple-negative breast tumors when injected into immune deficient mice. The same observation holds true for clinical studies implying increased HCMV protein expression in triple negative breast cancer biopsies. In addition to functionally being able to hijack tumor-promoting cellular events, HCMV is known to exhibit a wide range of immunosuppressive effects, which can have radical impact on the tumor microenvironment. HCMV infected cells can avoid recognition and elimination by the immune system by orchestrating polarization of immunosuppressive type II macrophages, preventing antigen presentation, by expressing T cell inhibitory molecules, and possibly, by the induction of regulatory T (Treg) cell responses. These actions would be especially deleterious for the antigenic activation and proliferation of tumor specific CD8⁺ cytotoxic T lymphocytes (CTLs), whose effector functions have recently been targeted by successful, experimental immunotherapy protocols. The recognition of alternative causes and drivers of breast cancer is a pivotal research topic for the development of diagnostics and novel, effective preventive and therapeutic strategies targeting both tumor cells and their microenvironments.

WDR5 inhibition halts metastasis dissemination by repressing the mesenchymal phenotype of breast cancer cells

Background

Development of metastases and drug resistance are still a challenge for a successful systemic treatment in breast cancer (BC) patients. One of the mechanisms that confer metastatic properties to the cell relies in the epithelial-to-mesenchymal transition (EMT). Moreover, both EMT and metastasis are partly modulated through epigenetic mechanisms, by repression or induction of specific related genes.

Methods

We applied shRNAs and drug targeting approaches in BC cell lines and metastatic patient-derived xenograft (PDX) models to inhibit WDR5, the core subunit of histone H3 K4 methyltransferase complexes, and evaluate its role in metastasis regulation.

Result

We report that WDR5 is crucial in regulating tumorigenesis and metastasis spreading during BC progression. In particular, WDR5 loss reduces the metastatic properties of the cells by reverting the mesenchymal phenotype of triple negative- and luminal B-derived cells, thus inducing an epithelial trait. We also suggest that this regulation is mediated by TGFβ1, implying a prominent role of WDR5 in driving EMT through TGFβ1 activation. Moreover, such EMT reversion can be induced by drug targeting of WDR5 as well, leading to BC cell sensitization to chemotherapy and enhancement of paclitaxel-dependent effects.

Conclusions

We suggest that WDR5 inhibition could be a promising pharmacologic approach to reduce cell migration, revert EMT, and block metastasis formation in BC, thus overcoming resistance to standard treatments.

Association Between Head and Neck Cancers and Polymorphisms 869T/C, 509C/T, and 915G/C of the Transforming Growth Factor-β1 Gene: A Meta-Analysis of Case-Control Studies

Background

Worldwide, head and neck cancers are the eighth most common malignancy. Single nucleotide polymorphisms (SNPs) are associated with susceptibility to cancer and sensitivity to radiotherapy and chemotherapy. The inflammatory cytokine, transforming growth factor-β1 (TGF-β1), is involved in the progression of malignancy. This study aimed to systematically review the literature and undertake a meta-analysis of case-control studies on the association between 869T/C, 509C/T, and 915G/C polymorphisms of the TGF-β1 gene and head and neck cancers.

Material/Methods

The published literature in the English and Chinese languages were searched to identify relevant studies reporting TGF-β1 gene polymorphisms and head and neck cancer. The PubMed, Embase, Wanfang Data, and CNKI databases were searched. Data were extracted from eligible studies, and meta-analysis was performed using Stata version 12.0 software.

Results

Ten case-control studies were identified. There was a significant association between the 869T/C polymorphism of the TGF-β1 gene and susceptibility to head and neck cancer. Subgroup analysis showed that the 869T/C polymorphism was not significantly associated with the histological type of head and neck cancer, but was significantly associated with susceptibility to head and neck cancer in the Asian population. The 509C/T polymorphism of the TGF-β1 gene was not significantly associated with susceptibility to nasopharyngeal cancer (NPC), but the 915G/C polymorphism was associated with susceptibility to oral cancer.

Conclusions

Data from this meta-analysis showed that the 869T/C and 915G/C polymorphisms of the TGF-β1 gene might be associated with susceptibility to head and neck cancer.

GREM1 is associated with metastasis and predicts poor prognosis in ER-negative breast cancer patients

Background

In breast cancer, activation of bone morphogenetic protein (BMP) signaling and elevated levels of BMP-antagonists have been linked to tumor progression and metastasis. However, the simultaneous upregulation of BMPs and their antagonist, and the fact that both promote tumor aggressiveness seems contradictory and is not fully understood.

Methods

We analyzed the transcriptomes of the metastatic 66cl4 and the non-metastatic 67NR cell lines of the 4T1 mouse mammary tumor model to search for factors that promote metastasis. CRISPR/Cas9 gene editing was used for mechanistic studies in the same cell lines. Furthermore, we analyzed gene expression patterns in human breast cancer biopsies obtained from public datasets to evaluate co-expression and possible relations to clinical outcome.

Results

We found that mRNA levels of the BMP-antagonist Grem1, encoding gremlin1, and the ligand Bmp4 were both significantly upregulated in cells and primary tumors of 66cl4 compared to 67NR. Depletion of gremlin1 in 66cl4 could impair metastasis to the lungs in this model. Furthermore, we found that expression of Grem1 correlated with upregulation of several stem cell markers in 66cl4 cells compared to 67NR cells. Both in the mouse model and in patients, expression of GREM1 associated with extracellular matrix organization, and formation, biosynthesis and modification of collagen. Importantly, high expression of GREM1 predicted poor prognosis in estrogen receptor negative breast cancer patients. Analyses of large patient cohorts revealed that amplification of genes encoding BMP-antagonists and elevation of the corresponding transcripts is evident in biopsies from more than half of the patients and much more frequent for the secreted BMP-antagonists than the intracellular inhibitors of SMAD signaling.

Conclusion

In conclusion, our results show that GREM1 is associated with metastasis and predicts poor prognosis in ER-negative breast cancer patients. Gremlin1 could represent a novel target for therapy.

Pharmacology Study of the Multiple Angiogenesis Inhibitor RC28-E on Anti-Fibrosis in a Chemically Induced Lung Injury Model

Background: Disease-related injury in any organ triggers a complex cascade of cellular and molecular responses that culminate in tissue fibrosis, inflammation, and angiogenesis simultaneously. Multiple cell angiogenesis is an essential part of the tissue damage response, which is involved in fibrosis development. RC28-E is a novel recombinant dual decoy receptor lgG1 Fc-fusion protein that can block vascular endothelial growth factor (VEGFA), platelet-derived growth factor (PDGF), and fibroblast growth factor-2 (FGF-2) simultaneously. This protein has stepped into clinical trials (NCT03777254) for the treatment of pathological neovascularization-related diseases. Here, we report on the role of RC28-E during anti-fibrosis and its potential multitarget function in regulating fibrosis. Methods: A bleomycin-induced pulmonary fibrosis C57BL/6 mouse model was established. Hematoxylin and eosin staining (HE) and Masson staining (Masson’s) were performed to evaluate the pulmonary fibrosis based on the scoring from, Ashcroft score. Fibrosis related factors and inflammatory cytokines including HYP, α-SMA, procollagen, ICAM, IL-6, IL-1, and TNF-α were also determined at the protein and mRNA levels to characterize the fibrosis. Both mRNA and protein levels of VEGF, FGF, and transforming growth factor (TGF)-β were detected by quantitative real-time PCR (qRT-PCR) and immunohistochemical (IHC) analysis, respectively. Pulmonary fibrosis and related cytokines were re-evaluated in vivo after 3 doses of RC28-E (5 mg/kg, 15 mg/kg, and 50 mg/kg, ip. Tiw × 9) in comparison with a mono-target antagonist treatment (VEGF or FGF blocking). RC28-E attenuated the activation of TGF-β induced fibroblasts in vitro. Expression levels of α-SMA and collagen I, as well as proliferation and migration, were determined with the human skin fibroblast cell line Detroit 551 and primary murine pulmonary fibroblast cells. The mechanism of RC28-E via the TGF-β/Smad pathway was also investigated. Results: RC28-E exhibits significant anti-fibrosis effects on Idiopathic pulmonary fibrosis (IPF) in vivo. Moreover, TGF-β induced fibroblast activation in vitro via the inhibition of the TGF-β downstream Smad pathway, thus providing potential therapeutics for clinical disease-related fibrosis-like IPF as well as chemotherapy-induced fibrosis in cancer therapy.

T Regulatory Cells and Priming the Suppressive Tumor Microenvironment

Treg play a central role in maintenance of self tolerance and homeostasis through suppression of self-reactive T cell populations. In addition to that role, Treg also survey cancers and suppress anti-tumor immune responses. Thus, understanding the unique attributes of Treg-tumor interactions may permit control of this pathologic suppression without interfering with homeostatic self-tolerance. This review will define the unique role of Treg in cancer growth, and the ways by which Treg inhibit a robust anti-tumor immune response. There will be specific focus placed on Treg homing to the tumor microenvironment (TME), TME formation of induced Treg (iTreg), mechanisms of suppression that underpin cancer immune escape, and trophic nonimmunologic effects of Treg on tumor cells.

Corilagin in Cancer: A Critical Evaluation of Anticancer Activities and Molecular Mechanisms

Corilagin (β-1-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-d-glucose), an ellagitannin, is one of the major bioactive compounds present in various plants. Ellagitannins belong to the hydrolyzable tannins, a group of polyphenols. Corilagin shows broad-spectrum biological, and therapeutic activities, such as antioxidant, anti-inflammatory, hepatoprotective, and antitumor actions. Natural compounds possessing antitumor activities have attracted significant attention for treatment of cancer. Corilagin has shown inhibitory activity against the growth of numerous cancer cells by prompting cell cycle arrest at the G2/M phase and augmented apoptosis. Corilagin-induced apoptosis and autophagic cell death depends on production of intracellular reactive oxygen species in breast cancer cell line. It blocks the activation of both the canonical Smad and non-canonical extracellular-signal-regulated kinase/Akt (protein kinase B) pathways. The potential apoptotic action of corilagin is mediated by altered expression of procaspase-3, procaspase-8, procaspase-9, poly (ADP ribose) polymerase, and Bcl-2 Bax. In nude mice, corilagin suppressed cholangiocarcinoma growth and downregulated the expression of Notch1 and mammalian target of rapamycin. The aim of this review is to summarize the anticancer efficacy of corilagin with an emphasis on the molecular mechanisms involving various signaling pathways in tumor cells.

Multiple actions of parathyroid hormone-related protein in breast cancer bone metastasis

The sequence similarity within the amino-terminal regions of parathyroid hormone (PTH) and PTH-related protein (PTHrP) allows the two to share actions at a common site, the PTH1 receptor. A number of biological activities have been ascribed to actions of other domains within PTHrP. PTHrP production by late stage breast cancer has been shown to contribute to bone metastasis formation through promotion of osteoclast formation and bone resorption by action through PTH1 receptors. There is evidence also for a role for PTHrP early in breast cancer that is protective against tumour progression. No signalling pathway has been identified for this effect. PTHrP has also been identified as a factor promoting the emergence of breast cancer cells from dormancy in bone. In that case, PTHrP does not function through activation of PTH1 receptors, despite having very substantial effects on transcriptional activity of the breast cancer cells. This indicates actions of PTHrP that are non-canonical, that is, mediated through domains other than the amino-terminal. It is concluded that PTHrP has several distinct paracrine, autocrine, and intracrine actions in the course of breast cancer pathophysiology. Some are mediated through action at PTH1 receptors and others are controlled by other domains within PTHrP. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.

A Longitudinal Study of the Association between Mammographic Density and Gene Expression in Normal Breast Tissue

High mammographic density (MD) is associated with a 4-6 times increase in breast cancer risk. For post-menopausal women, MD often decreases over time, but little is known about the underlying biological mechanisms. MD reflects breast tissue composition, and may be associated with microenvironment subtypes previously identified in tumor-adjacent normal tissue. Currently, these subtypes have not been explored in normal breast tissue. We obtained biopsies from breasts of healthy women at two different time points several years apart and performed microarray gene expression analysis. At time point 1, 65 samples with both MD and gene expression were available. At time point 2, gene expression and MD data were available from 17 women, of which 11 also had gene expression data available from the first time point. We validated findings from our previous study; negative correlation between RBL1 and MD in post-menopausal women, indicating involvement of the TGFβ pathway. We also found that breast tissue samples from women with a large decrease in MD sustained higher expression of genes in the histone family H4. In addition, we explored the previously defined active and inactive microenvironment subtypes and demonstrated that normal breast samples of the active subtype had characteristics similar to the claudin-low breast cancer subtype. Breast biopsies from healthy women are challenging to obtain, but despite a limited sample size, we have identified possible mechanisms relevant for changes in breast biology and MD over time that may be of importance for breast cancer risk and tumor initiation.

Actin Cytoskeleton and Focal Adhesions Regulate the Biased Migration of Breast Cancer Cells on Nanoscale Asymmetric Sawteeth

Physical guidance from the underlying matrix is a key regulator of cancer invasion and metastasis. We explore the effects of surface topography on the migration phenotype of multiple breast cancer cell lines using aligned nanoscale ridges and asymmetric sawtooth structures. Both benign and metastatic breast cancer cells preferentially move parallel to nanoridges, with enhanced speeds compared to flat surfaces. In contrast, asymmetric sawtooth structures unidirectionally bias the movement of breast cancer cells in a cell-type-dependent manner. Quantitative analysis shows that the level of bias in cell migration increases when cells move with higher speeds or with higher directional persistence. Live-cell imaging studies further reveal that actin polymerization waves are unidirectionally guided by the sawteeth in the same direction as the cell motion. High-resolution fluorescence imaging and scanning electron microscopy studies reveal that two breast cancer cell lines with opposite migrational profiles exhibit profoundly different cell cortical plasticity and focal adhesion patterns. These results suggest that the overall migration response of cancer cells to surface topography is directly related to the underlying cytoskeletal architectures and dynamics, which are regulated by both intrinsic and extrinsic factors.

Activin A Signaling Regulates IL13Rα2 Expression to Promote Breast Cancer Metastasis

Metastatic dissemination of cancer cells to distal organs is the major cause of death for patients suffering from the aggressive basal-like breast cancer (BLBC) subtype. Recently, we have shown that interleukin 13 receptor alpha 2 (IL13Rα2) is a critical gene that is overexpressed in a subset of BLBC primary tumors associated with poor distant metastasis-free survival (DMFS) and can promote extravasation and metastasis of breast cancer cells to the lungs. However, the upstream signaling mechanisms that promote aberrant IL13Rα2 expression during tumor progression remain unknown. Driven by our previously published gene expression microarray data derived from a well-characterized cell line model for BLBC progression, we show that both Inhibin βA (INHBA) and IL13Rα2 genes exhibit similarly higher expression levels in metastatic compared to non-metastatic cells and that overexpression of both genes predicts worse metastasis-free survival of patients with high grade tumors. Activin A, a member of the TGFβ superfamily comprising two INHBA subunits, has been shown to play context-depended roles in cancer progression. Here, we demonstrate that INHBA depletion downregulates IL13Rα2 expression in metastatic breast cancer cells, whereas treatment with Activin A in non-metastatic cells increases its expression levels. We also find that Activin A predominantly induces Smad2 phosphorylation and to a lesser extent activates Smad3 and Akt. Interestingly, we also show that Activin A-mediated upregulation of IL13Rα2 is Smad2-dependent since knocking down Smad2 or using the ALK4/ALK5 inhibitors EW-7197 and SB-505124 abolishes this effect. Most importantly, our data indicate that knocking down INHBA levels in breast cancer cells delays primary tumor growth, suppresses migration in vitro and inhibits the formation of lung metastases in vivo. Conclusively, our findings presented here suggest that the development of therapeutic interventions employing small molecule inhibitors against Activin receptors or neutralizing antibodies targeting Activin A ligand, could serve as alternative approaches against breast tumors overexpressing INHBA and/or IL13Rα2.

A natural antisense lncRNA controls breast cancer progression by promoting tumor suppressor gene mRNA stability

The human genome encodes thousands of long noncoding RNA (lncRNA) genes; the function of majority of them is poorly understood. Aberrant expression of a significant number of lncRNAs is observed in various diseases, including cancer. To gain insights into the role of lncRNAs in breast cancer progression, we performed genome-wide transcriptome analyses in an isogenic, triple negative breast cancer (TNBC/basal-like) progression cell lines using a 3D cell culture model. We identified significantly altered expression of 1853 lncRNAs, including ~500 natural antisense transcript (NATs) lncRNAs. A significant number of breast cancer-deregulated NATs displayed co-regulated expression with oncogenic and tumor suppressor protein-coding genes in cis. Further studies on one such NAT, PDCD4-AS1 lncRNA reveal that it positively regulates the expression and activity of the tumor suppressor PDCD4 in mammary epithelial cells. Both PDCD4-AS1 and PDCD4 show reduced expression in TNBC cell lines and in patients, and depletion of PDCD4-AS1 compromised the cellular levels and activity of PDCD4. Further, tumorigenic properties of PDCD4-AS1-depleted TNBC cells were rescued by exogenous expression of PDCD4, implying that PDCD4-AS1 acts upstream of PDCD4. Mechanistically, PDCD4-AS1 stabilizes PDCD4 RNA by forming RNA duplex and controls the interaction between PDCD4 RNA and RNA decay promoting factors such as HuR. Our studies demonstrate crucial roles played by NAT lncRNAs in regulating post-transcriptional gene expression of key oncogenic or tumor suppressor genes, thereby contributing to TNBC progression.

Breast cancer is the most common cancer in women worldwide. The molecular mechanisms underlying the disease have been extensively studied, leading to dramatic improvements in diagnostic and prognostic approaches. Despite the overall improvements in survival rate, numerous cases of death by breast cancer are still reported per year, alerting us about the potential gap of knowledge in cancer molecular biology era. The emerging advances in new generation sequencing techniques have revealed that the majority of genome is transcribed into non-protein coding RNAs or ncRNAs, including thousands of long ncRNAs (lncRNAs) of unknown function. Natural antisense RNAs (NATs) constitute a group of lncRNAs that are transcribed in the opposite direction to a sense protein-coding or non-coding gene with partial or complete complementarity. In this manuscript, we investigate the role of NATs in breast cancer progression, focusing on the role of PDCD4-AS1, a NAT expressed from the established tumor suppressor PDCD4 gene locus. We observe that both PDCD4-AS1 and PDCD4 display concordant expression in breast cancer cell lines and patients. In mammary epithelial cells, PDCD4-AS1 promotes the stability of PDCD4 mRNA. PDCD4-AS1 by forming RNA duplex with PDCD4 RNA prevents the interaction between PDCD4 RNA and RNA decay factors in the nucleus.

Palbociclib enhances activin-SMAD-induced cytostasis in estrogen receptor-positive breast cancer

Cyclin‐dependent kinase (CDK) 4 and CDK6 inhibitors are effective therapeutic options for hormone receptor (HR)‐positive, human epidermal growth factor receptor 2 (HER2)‐negative advanced breast cancer. Although CDK4/6 inhibitors mainly target the cyclin D‐CDK4/6‐retinoblastoma tumor suppressor protein (RB) axis, little is known about the clinical impact of inhibiting phosphorylation of other CDK4/6 target proteins. Here, we focused on other CDK4/6 targets, SMAD proteins. We showed that a CDK4/6 inhibitor palbociclib and activin‐SMAD2 signaling cooperatively inhibited cell cycle progression of a luminal‐type breast cancer cell line T47D. Palbociclib enhanced SMAD2 binding to the genome by inhibiting CDK4/6‐mediated linker phosphorylation of the SMAD2 protein. We also showed that cyclin G2 plays essential roles in SMAD2‐dependent cytostatic response. Moreover, comparison of the SMAD2 ChIP‐seq data of T47D cells with those of Hs578T (triple‐negative breast cancer cells) indicated that palbociclib augmented different SMAD2‐mediated functions based on cell type, and enhanced SMAD2 binding to the target regions on the genome without affecting its binding pattern. In summary, palbociclib enhances the cytostatic effects of the activin‐SMAD2 signaling pathway, whereas it possibly strengthens the tumor‐promoting aspect in aggressive breast cancer.

Functional Role of miRNAs in the Progression of Breast Ductal Carcinoma in Situ

miRNAs are small RNAs that influence gene expression by targeting mRNAs. Depending on the function of their target genes, miRNAs may regulate the expression of oncogenes and tumor suppressors, thereby contributing to the promotion or inhibition of tumor progression. Ductal carcinoma in situ (DCIS), although often diagnosed as breast cancer, is a potential precursor to invasive ductal carcinoma. Many of the genetic events required for the invasive progression of DCIS occur at the preinvasive stage, and these events include changes in the expression of miRNAs. Aberrant expression of miRNAs can influence specific oncogenic or tumor-suppressive pathways required for breast cancer progression. miRNAs in DCIS have been shown to influence hormone signaling, cell-cell adhesion, epithelial-to-mesenchymal transition, transforming growth factor β signaling, maintenance of cancer stem cells, and modulation of the extracellular matrix. Additionally, extracellular DCIS miRNAs, such as those found in exosomes, may promote invasive progression by modifying the tumor microenvironment. Here, we review the miRNAs that have been identified in DCIS and how they may contribute to the progression to invasive disease. We also touch on the current state of miRNA therapy development, including the current challenges, and discuss the key future perspectives for research into miRNA function for the purpose of miRNA therapy development for DCIS.

TGF-β Sustains Tumor Progression through Biochemical and Mechanical Signal Transduction

Transforming growth factor β (TGF-β) signaling transduces immunosuppressive biochemical and mechanical signals in the tumor microenvironment. In addition to canonical SMAD transcription factor signaling, TGF-β can promote tumor growth and survival by inhibiting proinflammatory signaling and extracellular matrix (ECM) remodeling. In this article, we review how TGF-β activated kinase 1 (TAK1) activation lies at the intersection of proinflammatory signaling by immune receptors and anti-inflammatory signaling by TGF-β receptors. Additionally, we discuss the role of TGF-β in the mechanobiology of cancer. Understanding how TGF-β dampens proinflammatory responses and induces pro-survival mechanical signals throughout cancer development is critical for designing therapeutics that inhibit tumor progression while bolstering the immune response.

Genetic Modifiers of the Breast Tumor Microenvironment

Multiple nonmalignant cell types in the tumor microenvironment (TME) impact breast cancer risk, metastasis, and response to therapy, yet most heritable mechanisms that influence TME cell function and breast cancer outcomes are largely unknown. Breast cancer risk is ∼30% heritable and >170 genetic loci have been associated with breast cancer traits. However, the majority of candidate genes have poorly defined mechanistic roles in breast cancer biology. Research indicates that breast cancer risk modifiers directly impact cancer cells, yet it is equally plausible that some modifier alleles impact the nonmalignant TME. The objective of this review is to examine the list of current breast cancer candidate genes that may modify breast cancer risk and outcome through the TME.

Lysophosphatidic acid regulates the motility of MCF10CA1a breast cancer cell sheets via two opposing signaling pathways

Aberrant cell migration leads to the dispersal of malignant cells. The ubiquitous lipid mediator lysophosphatidic acid (LPA) modulates cell migration and is implicated in tumor progression. Yet, the signaling cascades that regulate LPA's effect on cell motility remain unclear. Using time-lapse imaging and quantitative analyses, we studied the role of signaling cascades that act downstream of LPA on the motility of MCF10CA1a breast cancer cells. We found that LPA alters cell motility via two major signaling pathways. The Rho/ROCK signaling cascade is the predominant pathway that increases E-Cadherin containing cell-cell adhesions and cortical arrangement of actomyosin to promote slow, directional, spatially coherent and temporally consistent movement. In contrast, Gαi/o- and Gαq/11-dependent signaling cascades lessen directionality and support the independent movement of cells. The net effect of LPA on breast cancer cell migration therefore results from the integrated signaling activity of the Rho/ROCK and Gαi/o- and Gαq/11-dependent pathways, thus allowing for a dynamic migratory response to changes in the cellular or microenvironmental context.

Human cytomegalovirus glycoprotein B inhibits migration of breast cancer MDA-MB-231 cells and impairs TGF-β/Smad2/3 expression

Breast cancer is a leading cause of cancer-associated mortality in females worldwide and evidence suggests that human cytomegalovirus (HCMV) infection may be implicated in the progress of breast cancer. HCMV glycoprotein B (gB) is the most abundant envelope protein and serves an important role in host cell entry. The present study aimed to clarify the role of HCMV gB in breast cancer cells. A HCMV gB construct (UL55) was generated and stable vUL55 gene lentivirus-transfected MDA-MB-231 cells were established. Subsequently, the effect of HCMV gB on the apoptosis and proliferation of MDA-MB-231 cells was measured by flow cytometry and Cell Counting Kit-8 assay. Furthermore, whether HCMV gB may modulate MDA-MB-231 cell migration was examined using Transwell and cell scratch assays. In addition, alterations in HCMV gB-modulated protein levels of transforming growth factor-β (TGF-β) and Mothers against decapentaplegic homologs 2/3 (Smad2/3) were detected using western blot analysis. The results indicated that UL55 cDNA was stably transfected into MDA-MB-231 cells, and that HCMV gB protein was stably expressed. No significant differences in cell apoptosis and proliferation between transfected (231-GB-OE) and negative control (231-NC) cells were observed, while the rate of cell migration was significantly decreased in the 231-GB-OE cells compared with the 231-NC cells. Additionally, the expression level of TGF-β and phosphorylation level of Smad2/3 were also decreased in 231-GB-OE cells compared with the 231-NC cells. Although certain previous studies indicated that HCMV infection was associated with breast carcinogenesis, the results of the present study indicate that the envelope protein HCMV gB exhibits no effect on cell apoptosis and proliferation, but inhibits breast cancer cell migration. This may be due to downregulated TGF-β/Smad signaling. Taken together, these studies may assist in developing anti-TGF-β agents that contribute to tumor suppression.

The Long (lncRNA) and Short (miRNA) of It: TGFβ-Mediated Control of RNA-Binding Proteins and Noncoding RNAs

RNA-binding proteins (RBP) and noncoding RNAs (ncRNA), such as long noncoding RNAs (lncRNA) and microRNAs (miRNA), control co- and posttranscriptional gene regulation (PTR). At the PTR level, RBPs and ncRNAs contribute to pre-mRNA processing, mRNA maturation, transport, localization, turnover, and translation. Deregulation of RBPs and ncRNAs promotes the onset of cancer progression and metastasis. Both RBPs and ncRNAs are altered by signaling cascades to cooperate or compete with each other to bind their nucleic acid targets. Most importantly, transforming growth factor-beta (TGFβ) signaling plays a significant role in controlling gene expression patterns by targeting RBPs and ncRNAs. Because of TGFβ signaling in cancer, RBP-RNA or RNA-RNA interactions are altered and cause enhanced cell growth and tumor cell dissemination. This review focuses on the emerging concepts of TGFβ signaling on posttranscriptional gene regulation and highlights the implications of RBPs and ncRNAs in cancer progression and metastasis. Mol Cancer Res; 16(4); 567-79. ©2018 AACR.

Molecular Mechanisms and Emerging Therapeutic Targets of Triple-Negative Breast Cancer Metastasis

Breast cancer represents a highly heterogeneous disease comprised by several subtypes with distinct histological features, underlying molecular etiology and clinical behaviors. It is widely accepted that triple-negative breast cancer (TNBC) is one of the most aggressive subtypes, often associated with poor patient outcome due to the development of metastases in secondary organs, such as the lungs, brain, and bone. The molecular complexity of the metastatic process in combination with the lack of effective targeted therapies for TNBC metastasis have fostered significant research efforts during the past few years to identify molecular “drivers” of this lethal cascade. In this review, the most current and important findings on TNBC metastasis, as well as its closely associated basal-like subtype, including metastasis-promoting or suppressor genes and aberrantly regulated signaling pathways at specific stages of the metastatic cascade are being discussed. Finally, the most promising therapeutic approaches and novel strategies emerging from these molecular targets that could potentially be clinically applied in the near future are being highlighted.

MiR-148a functions to suppress metastasis and serves as a prognostic indicator in triple-negative breast cancer

Triple-negative breast cancer (TNBC) presents a major challenge in the clinic due to its lack of reliable prognostic markers and targeted therapies. Accumulating evidence strongly supports the notion that microRNAs (miRNAs) are involved in tumorigenesis and could serve as biomarkers for diagnostic purposes. To identify miRNAs that functionally suppress metastasis of TNBC, we employed a concerted approach with selecting miRNAs that display differential expression profiles from bioinformatic analyses of breast cancer patient databases and validating top candidates with functional assays using breast cancer cell lines and mouse models. We have found that miR-148a exhibits properties as a tumor suppressor as its expression is inversely correlated with the ability of both human and mouse breast cancer cells to colonize the lung in mouse xenograft tumor models. Mechanistically, miR-148a appears to suppress the extravasation process of cancer cells, likely by targeting two genes WNT1 and NRP1 in a cell non-autonomous manner. Importantly, lower expression of miR-148a is detected in higher-grade tumor samples and correlated with increased likelihood to develop metastases and poor prognosis in subsets of breast cancer patients, particularly those with TNBC. Thus, miR-148a is functionally defined as a suppressor of breast cancer metastasis and may serve as a prognostic biomarker for this disease.

Dual roles of miR-374a by modulated c-Jun respectively targets CCND1-inducing PI3K/AKT signal and PTEN-suppressing Wnt/β-catenin signaling in non-small-cell lung cancer

MiR-374a appears to play a complex role in non-small-cell lung cancer (NSCLC). Here, we demonstrate a dual role for miR-374a in NSCLC pathogenesis. The effects and modulatory mechanisms of miR-374a on cell growth, migration, invasion, and in vivo tumorigenesis and metastasis in nude mice were also analyzed. The expression of miR-374a was examined in NSCLC and non-cancerous lung tissues by quantitative real-time reverse transcription-PCR (qRT-PCR), and in situ hybridization, respectively. miR-374a directly targets CCND1 and inactivates PI3K/AKT and Ras-mediated cell cycle signalings, as well as epithelial–mesenchymal transition (EMT). This not only dramatically suppressed cell growth, migration, invasion,and metastasis, but also elevated A549 and pc-9 NSCLC cell sensitivity to cisplatin (DDP) while increasing survival time of tumor-bearing mice. Interestingly, miR-374a serves an inverse function in SPCA-1 and H1975 NSCLC cells by directly targeting PTEN to activate Wnt/β-catenin and Ras signalings and its downstream cascade signals. Surprisingly, transcription factor c-Jun bound to the promoter region of human miR-374a and suppressed miR-374a in A549 and pc-9 cells while inducing it in SPCA-1 and H1975 cells. Increased levels of miR-374a appeared to serve a protective role by targeting CCND1 in early-stage NSCLC (Stages I and II). Inversely, increased miR-374a was an unfavorable factor when targeting PTEN in more advanced staged NSCLC patients. Our studies are the first to demonstrate that miR-374a plays divergent roles in NSCLC pathogenesis at different stages of the disease and implicate the potential application of miR-374a targeting for cancer therapy.

Semaphorin 4D in human head and neck cancer tissue and peripheral blood: A dense fibrotic peri-tumoral stromal phenotype

The search for stromal biomarkers in carcinoma patients is a challenge in the field. Semaphorin 4D (Sema4D), known for its various developmental, physiological and pathological effects, plays a role in pro and anti-inflammatory responses. It is expressed in many epithelial tumors including head and neck squamous cell carcinoma (HNSCC). Recently, we found that HNSCC-associated Sema4D modulates an immune-suppressive, tumor-permissible environment by inducing the expansion of myeloid derived suppressor cells. The purpose of this study was to determine the value of Sema4D as a biomarker for the peri-tumoral stromal phenotype in human HNSCC. Our data showed Sema4D^+ve/high tumor cells in 34% of the studied cohort with positive correlation to Stage III (p=0.0001). Sema4D^+ve/high tumor cells correlated directly with dense fibrotic peri-tumoral stroma (p=0.0001) and inversely with infiltrate of Sema4D^+ve/high tumor-associated inflammatory cells (TAIs) (p=0.01). Most of the Sema4D^+ve/high TAIs were co-positive for the macrophage biomarker CD163. Knockdown of Sema4D in WSU-HN6 cells inhibited collagen production by fibroblasts, and decreased activated TGF-β1 levels in culture medium of HNSCC cell lines. In a stratification model of HNSCC using combined Sema4D and the programmed death ligand 1 (PDL-1), Sema4D^+ve/high tumor cells represented a phenotype distinct from the PDL-1 positive tumors. Finally,Sema4D was detected in plasma of HNC patients at significantly higher levels (115.44, ± 39.37) compared to healthy donors (38.60± 12.73) (p <0.0001). In conclusion, we present a novel HNSCC tumor stratification model, based on the expression of the biomarker Sema4D. This model opens new avenues to novel targeted therapeutic strategies.

Functional and prognostic significance of long non-coding RNA MALAT1 as a metastasis driver in ER negative lymph node negative breast cancer

MALAT1 (metastasis associated lung adenocarcinoma transcript1) is a conserved long non-coding RNA, known to regulate gene expression by modulating transcription and post-transcriptional pre-mRNA processing of a large number of genes. MALAT1 expression is deregulated in various tumors, including breast cancer. However, the significance of such abnormal expression is yet to be fully understood. In this study, we demonstrate that regulation of aggressive breast cancer cell traits by MALAT1 is not predicted solely based on an elevated expression level but is context specific. By performing loss- and gain-of-function studies, both under in vitro and in vivo conditions, we demonstrate that MALAT1 facilitates cell proliferation, tumor progression and metastasis of triple-negative breast cancer (TNBC) cells despite having a comparatively lower expression level than ER or HER2-positive breast cancer cells. Furthermore, MALAT1 regulates the expression of several cancer metastasis-related genes, but displays molecular subtype specific correlations with such genes. Assessment of the prognostic significance of MALAT1 in human breast cancer (n=1992) revealed elevated MALAT1 expression was associated with decreased disease-specific survival in ER negative, lymph node negative patients of the HER2 and TNBC molecular subtypes. Multivariable analysis confirmed MALAT1 to have independent prognostic significance in the TNBC lymph node negative patient subset (HR=2.64, 95%CI 1.35 − 5.16, p=0.005). We propose that the functional significance of MALAT1 as a metastasis driver and its potential use as a prognostic marker is most promising for those patients diagnosed with ER negative, lymph node negative breast cancer who might otherwise mistakenly be stratified to have low recurrence risk.

Clair DK, Kyprianou N. Profiles of Radioresistance Mechanisms in Prostate Cancer

Radiation therapy (RT) is commonly used for the treatment of localized prostate cancer (PCa). However, cancer cells often develop resistance to radiation through unknown mechanisms and pose an intractable challenge. Radiation resistance is highly unpredictable, rendering the treatment less effective in many patients and frequently causing metastasis and cancer recurrence. Understanding the molecular events that cause radioresistance in PCa will enable us to develop adjuvant treatments for enhancing the efficacy of RT. Radioresistant PCa depends on the elevated DNA repair system and the intracellular levels of reactive oxygen species (ROS) to proliferate, self-renew, and scavenge anti-cancer regimens, whereas the elevated heat shock protein 90 (HSP90) and the epithelial-mesenchymal transition (EMT) enable radioresistant PCa cells to metastasize after exposure to radiation. The up-regulation of the DNA repairing system, ROS, HSP90, and EMT effectors has been studied extensively, but not targeted by adjuvant therapy of radioresistant PCa. Here, we emphasize the effects of ionizing radiation and the mechanisms driving the emergence of radioresistant PCa. We also address the markers of radioresistance, the gene signatures for the predictive response to radiotherapy, and novel therapeutic platforms for targeting radioresistant PCa. This review provides significant insights into enhancing the current knowledge and the understanding toward optimization of these markers for the treatment of radioresistant PCa.

Transforming growth factor-β promotes aggressiveness and invasion of clear cell renal cell carcinoma

The molecular mechanisms whereby transforming growth factor-β (TGF-β) promotes clear cell renal cell carcinoma (ccRCC) progression is elusive. The cell membrane bound TGF-β type I receptor (ALK5), was recently found to undergo proteolytic cleavage in aggressive prostate cancer cells, resulting in liberation and subsequent nuclear translocation of its intracellular domain (ICD), suggesting that ALK5-ICD might be a useful cancer biomarker. Herein, the possible correlation between ALK5 full length (ALK5-FL) and ALK5-ICD protein, phosphorylated Smad2/3 (pSmad2/3), and expression of TGF-β target gene PAI-1, was investigated in a clinical ccRCC material, in relation to tumor grade, stage, size and cancer specific survival. Expression of ALK5-FL, ALK5-ICD, pSmad2/3 and PAI-1 protein levels were significantly higher in higher stage and associated with adverse survival. ALK5-ICD, pSmad2/3 and PAI-1 correlated with higher grade, and ALK5-FL, pSmad2/3 and PAI-1 protein levels were significantly correlated with larger tumor size. Moreover, the functional role of the TGF-β - ALK5-ICD pathway were investigated in two ccRCC cell lines by treatment with ADAM/MMP2 inhibitor TAPI-2, which prevented TGF-β-induced ALK5-ICD generation, nuclear translocation, as well as cell invasion. The present study demonstrated that canonical TGF-β Smad2/3 pathway and generation of ALK5-ICD correlates with poor survival and invasion of ccRCC in vitro.

MicroRNA-323-3p inhibits cell invasion and metastasis in pancreatic ductal adenocarcinoma via direct suppression of SMAD2 and SMAD3

Pancreatic ductal adenocarcinoma (PDAC), which accounts for 96% of all pancreatic cancer cases, is characterized by rapid progression, invasion and metastasis. Transforming growth factor-beta (TGF-β) signaling is an essential pathway in metastatic progression and microRNAs (miRNA) play central roles in the regulation of various biological and pathologic processes including cancer metastasis. However, the molecular mechanisms involved in regulation of miRNAs and activation of TGF-β signaling in PDAC remain to be established. The results of this study suggested that miR-323-3p expression in PDAC tissues and cell lines was significantly decreased compared to levels in normal pancreatic tissues and primary cultured pancreatic duct epithelial cells. Further investigation revealed that miR-323-3p directly targeted and suppressed SMAD2 and SMAD3, both key components in TGF-β signaling. Lower levels of miR-323-3p predicted poorer prognosis in patients with PDAC. Ectopic overexpression of miR-323-3p significantly inhibited, while silencing of miR-323-3p increased the migration and invasion abilities of PDAC cells in vitro. Moreover, using an in vivo mouse model, we demonstrated that overexpressing of miR-323-3p significantly reduced, while knockdown of miR-323-3p enhanced lung metastatic colonization of PANC-1 cells. Furthermore, miR-323-3p-induced TGF-b signaling inhibition and cell motility suppression were partially rescued by overexpressing of Smad2 and Smad3 in PDAC cells. Our findings suggest that re-expression of miR-323-3p might offer a novel therapeutic target against metastasis in patients with PDAC.

Using the Dot Assay to Analyze Migration of Cell Sheets

Although complex organisms appear static, their tissues are under a continuous turnover. As cells age, die, and are replaced by new cells, cells move within tissues in a tightly orchestrated manner. During tumor development, this equilibrium is disturbed, and tumor cells leave the epithelium of origin to invade the local microenvironment, to travel to distant sites, and to ultimately form metastatic tumors at distant sites. The dot assay is a simple, two-dimensional unconstrained migration assay, to assess the net movement of cell sheets into a cell-free area, and to analyze parameters of cell migration using time-lapse imaging. Here, the dot assay is demonstrated using a human invasive, lung colony forming breast cancer cell line, MCF10CA1a, to analyze the cells' migratory response to epidermal growth factor (EGF), which is known to increase malignant potential of breast cancer cells and to alter the migratory phenotype of cells.

Association between TGF-β1 Polymorphisms and Head and Neck Cancer Risk: A Meta-Analysis

Background and Objective: Studies have been conducted to explore the association between the single nucleotide polymorphisms (SNPs) in transforming growth factor beta 1 (TGF-β1) and head and neck cancer (HNC) susceptibility, however the findings are still inconclusive. Therefore, we conduct this meta-analysis to quantitatively assess the association.

Methods: Embase and PubMed were searched for all eligible clinical studies. The odds ratio (OR) and 95% confidence interval (CI) of each study were pooled to estimate the association between SNPs in the TGF-β1 and the HNC risk. Subgroup analysis was used to explore whether particular characteristics were related to the value of overall ORs and 95% CIs.

Results: Seven case-control studies, including three SNPs (−509C/T, 869T/C, and 915G/C), were examined. Overall, this meta-analysis failed to identify a significant association between TGF-β1−509C/T, 915G/C polymorphism and HNC risk in any models. As for the 869T/C polymorphism, significant associations were observed in the allelic model (C vs. T: OR = 1.351, 95%CI: 1.030–1.772), the homozygote model (CC vs. TT: OR = 1.585, 95%CI: 1.026–2.449) and the dominant model (CT/CC vs. TT: OR = 1.398, 95%CI: 1.008–1.937). This polymorphism was also found in the Asian group as well (C vs. T: OR = 1.400, 95%CI: 1.003–1.956, CC vs. TT: OR = 1.814, 95%CI: 1.018–3.233).

Conclusion: Meta-analysis failed to show a statistical association between TGF-β1−509C/T, 915G/C polymorphism, and HNC risk in any genetic models. However, it was found that TGF-β1 869C/T polymorphism may be involved in susceptibility to HNC, especially in Asian patients. However, given the limitations of this meta-analysis, further well-designed studies are required in the future.

RNA-editing enzymes ADAR1 and ADAR2 coordinately regulate the editing and expression of Ctn RNA

Adenosine deaminases acting on RNA (ADARs) are proteins that catalyse widespread A-to-I editing within RNA sequences. We recently reported that ADAR2 edits and stabilizes nuclear-retained Cat2 transcribed nuclear RNA (Ctn RNA). Here, we report that ADAR1 coordinates with ADAR2 to regulate editing and stability of Ctn RNA. We observe an RNA-dependent interaction between ADAR1 and ADAR2. Furthermore, ADAR1 negatively regulates interaction of Ctn RNA with RNA-destabilizing proteins. We also show that breast cancer (BC) cells display elevated ADAR1 but not ADAR2 levels, compared to nontumourigenic cells. Additionally, BC patients with elevated levels of ADAR1 show low survival. Our findings provide insights into overlapping substrate preferences of ADARs and potential involvement of ADAR1 in BC.