Selective gene-expression profiling of migratory tumor cells in vivo predicts clinical outcome in breast cancer patients

MANF Promotes Unexplained Recurrent Miscarriages by Interacting with NPM1 and Downregulating Trophoblast Cell Migration and Invasion

Dysplasia and invasive defects in early trophoblasts contribute to unexplained recurrent miscarriages (URMs). Mesencephalic astrocyte-derived neurotrophic factor (MANF) inhibits migration and invasion in some cancer cells, but its role in pregnancy-related diseases remains unresolved. Here, we found that MANF levels in the peripheral blood and aborted tissue of URM women were higher than in normal controls, irrespective of pregnancy or miscarriage. We confirm the interaction between MANF and nucleophosmin 1 (NPM1) in trophoblasts of URM patients, which increases the ubiquitination degradation of NPM1, leading to upregulation of the p53 signaling pathway and inhibition of cell proliferation, migration, and invasion ability. Using a URM mouse model, we found that MANF downregulation resulted in reduced fetal resorption; however, concomitant NPM1 downregulation led to increased abortion rates. These data indicate that MANF triggers miscarriage via NPM1 downregulation and p53 activation. Thus, MANF downregulation or disruption of the MANF-NPM1 interaction could be targets for URM therapeutics.

Targeting ABCA12-controlled ceramide homeostasis inhibits breast cancer stem cell function and chemoresistance

Cancer stem cells (CSCs) drive tumor growth, metastasis, and chemoresistance. While emerging evidence suggests that CSCs have a unique dependency on lipid metabolism, the functions and regulation of distinct lipid species in CSCs remain poorly understood. Here, we developed a stem cell factor SOX9-based reporter for isolating CSCs in primary tumors and metastases of spontaneous mammary tumor models. Transcriptomic analyses uncover that SOX9high CSCs up-regulate the ABCA12 lipid transporter. ABCA12 down-regulation impairs cancer stemness and chemoresistance. Lipidomic analyses reveal that ABCA12 maintains cancer stemness and chemoresistance by reducing intracellular ceramide abundance, identifying a CSC-associated function of ABCA subfamily transporter. Ceramide suppresses cancer stemness by inhibiting the YAP-SOX9 signaling pathway in CSCs. Increasing ceramide levels in tumors enhances their sensitivity to chemotherapy and prevents the enrichment of SOX9high CSCs. In addition, SOX9high and ABCA12high cancer cells contribute to chemoresistance in human patient-derived xenografts. These findings identify a CSC-suppressing lipid metabolism pathway that can be exploited to inhibit CSCs and overcome chemoresistance.

Protooncogenic Role of ARHGAP11A and ARHGAP11B in Invasive Ductal Carcinoma: Two Promising Breast Cancer Biomarkers

Invasive duct carcinoma (IDC) is one of the most common types of breast cancer (BC) in women worldwide, with a high risk of malignancy, metastasis, recurrence, and death. So far, molecular patterns among IDC cases have not been fully defined. However, extensive evidence has shown that dysregulated Rho family small GTPases (Rho GTPases) including Rho GTPase activating proteins (RhoGAPs) have important roles in the invasive features of IDCs. In the current study, we analyzed the expression levels of two RhoGAP genes, ARHGAP11A and ARHGAP11B, in The Cancer Genome Atlas (TCGA) breast cancer (BRCA) and also our 51 IDC tumors compared to their matched normal tissues using quantitative polymerase chain reaction (qPCR). Our TCGA data analysis revealed higher expression of ARHGAP11A and ARHGAP11B in various cancers comprising BCs. Also, we found correlations between these genes and other genes in TCGA-BRCA. Moreover, our methylation analysis showed that their promotor methylation had a negative correlation with their overexpression. QPCR revealed their significant upregulation in our tumor samples. Furthermore, we found that the expression level of ARHGAP11A was considerably lower in women who were breastfeeding. Moreover, it had overexpression in cases who had regular menstrual cycles and early age (younger than 14) at menarche. However, ARHGAP11B had a higher expression in HER2-positive tumors versus HER2-positive and ER-positive tumors. Our study found possible protooncogenic roles for these genes and their involvement in IDC pathogenesis and malignancy. Therefore, they can be considered novel prognostic and diagnostic biomarkers for IDC.

Targeted Single-cell Isolation of Spontaneously Escaping Live Melanoma Cells for Comparative Transcriptomics

Solid cancer cells escape the primary tumor mass by transitioning from an epithelial-like state to an invasive migratory state. As they escape, metastatic cancer cells employ interchangeable modes of invasion, transitioning between fibroblast-like mesenchymal movement to amoeboid migration, where cells display a rounded morphology and navigate the extracellular matrix in a protease-independent manner. However, the gene transcripts that orchestrate the switch between epithelial, mesenchymal, and amoeboid states remain incompletely mapped, mainly due to a lack of methodologies that allow the direct comparison of the transcriptomes of spontaneously invasive cancer cells in distinct migratory states. Here, we report a novel single-cell isolation technique that provides detailed three-dimensional data on melanoma growth and invasion, and enables the isolation of live, spontaneously invasive cancer cells with distinct morphologies and invasion parameters. Via the expression of a photoconvertible fluorescent protein, compact epithelial-like cells at the periphery of a melanoma mass, elongated cells in the process of leaving the mass, and rounded amoeboid cells invading away from the mass were tagged, isolated, and subjected to single-cell RNA sequencing. A total of 462 differentially expressed genes were identified, from which two candidate proteins were selected for further pharmacologic perturbation, yielding striking effects on tumor escape and invasion, in line with the predictions from the transcriptomics data. This work describes a novel, adaptable, and readily implementable method for the analysis of the earliest phases of tumor escape and metastasis, and its application to the identification of genes underpinning the invasiveness of malignant melanoma.

Significance

This work describes a readily implementable method that allows for the isolation of individual live tumor cells of interest for downstream analyses, and provides the single-cell transcriptomes of melanoma cells at distinct invasive states, both of which open avenues for in-depth investigations into the transcriptional regulation of the earliest phases of metastasis.

Premenopausal women with breast cancer in the early post-partum period show molecular profiles of invasion and are associated with poor prognosis

PURPOSE

Young premenopausal women develop breast cancer (BC) within 5-10 years of the last childbirth, known as post-partum breast cancers (PPBC), often present with aggressive disease. The exact mechanisms that lead to poor prognosis in these patients are largely unknown.

METHODS

We have evaluated the association of clinical and reproductive factors with BC in a cohort of women ≤ 45 years (N = 155) with long-term follow-up. Based on duration since last childbirth (LCB), grouped patients into PPBC1 (LCB ≤ 5 years), PPBC2 (LCB between 6 and 10 years), PPBC3 (LCB > 10 years), and NPBC (age-matched nulliparous BC patients). We compared disease-free survival and hazard associated with recurrence/metastasis between the groups. RNA sequencing of tumor samples was performed from three parous groups (n = 10), and transcriptomic data were analyzed for differentially expressed genes and altered pathways.

RESULTS

Women in the PPBC1 group had an early menarche and late age at first and last childbirth compared to other groups. Survival analysis within lymph node-positive tumors showed that PPBC1 tumors had a worse prognosis than PPBC2 and NPBC tumors (p = 0.015 and p = 0.026, respectively). Clustering of the differentially expressed genes between the groups showed distinct expression in early PPBC (E-PPBC) tumors. Pathway analysis revealed upregulation of invasive-related pathways along with T cell exhaustion, extracellular matrix remodeling, angiogenesis, and epithelial-to-mesenchymal transition in E-PPBC tumors.

CONCLUSION

Early PPBC is a unique subtype with aggressive clinical features and distinct biology. Further research is needed to accurately project the risk of recurrence and optimal treatment strategies in these young patients.

Cooperative NF-κB and Notch1 signaling promotes macrophage-mediated MenaINV expression in breast cancer

Metastasis is a multistep process that leads to the formation of clinically detectable tumor foci at distant organs and frequently to patient demise. Only a subpopulation of breast cancer cells within the primary tumor can disseminate systemically and cause metastasis. To disseminate, cancer cells must express MenaINV, an isoform of the actin regulatory protein Mena, encoded by the ENAH gene, that endows tumor cells with transendothelial migration activity, allowing them to enter and exit the blood circulation. We have previously demonstrated that MenaINV mRNA and protein expression is induced in cancer cells by macrophage contact. In this study, we discovered the precise mechanism by which macrophages induce MenaINV expression in tumor cells. We examined the promoter of the human and mouse ENAH gene and discovered a conserved NF-κB transcription factor binding site. Using live imaging of an NF-κB activity reporter and staining of fixed tissues from mouse and human breast cancer, we further determined that for maximal induction of MenaINV in cancer cells, NF-κB needs to cooperate with the Notch1 signaling pathway. Mechanistically, Notch1 signaling does not directly increase MenaINV expression, but it enhances and sustains NF-κB signaling through retention of p65, an NF-κB transcription factor, in the nucleus of tumor cells, leading to increased MenaINV expression. In mice, these signals are augmented following chemotherapy treatment and abrogated upon macrophage depletion. Targeting Notch1 signaling in vivo decreased NF-κB signaling activation and MenaINV expression in the primary tumor and decreased metastasis. Altogether, these data uncover mechanistic targets for blocking MenaINV induction that should be explored clinically to decrease cancer cell dissemination and improve survival of patients with metastatic disease.

Double C-2 like domain beta (DOC2B) induces calcium dependent oxidative stress to promote lipotoxicity and mitochondrial dysfunction for its tumor suppressive function

Mitochondria are biosynthetic and bioenergetic organelles that regulate many biological processes, including metabolism, oxidative stress, and cell death. Cervical cancer (CC) cells show impairments in mitochondrial structure and function and are linked with cancer progression. DOC2B is a tumor suppressor with anti-proliferative, anti-migratory, anti-invasive, and anti-metastatic function in CC. For the first time, we demonstrated the role of the DOC2B-mitochondrial axis with tumor growth regulatory functions in CC. We used DOC2B overexpression and knockdown model systems to show that DOC2B is localized to mitochondria and induces Ca²⁺-mediated lipotoxicity. DOC2B expression induced mitochondrial morphological changes with the subsequent reduction in mitochondrial DNA copy number, mitochondrial mass, and mitochondrial membrane potential. Intracellular and mitochondrial Ca²⁺, intracellular O^.-₂, and ATP levels were substantially elevated in the presence of DOC2B. DOC2B manipulation reduced glucose uptake, lactate production, and mitochondrial complex-IV activity. The presence of DOC2B significantly reduced the proteins associated with mitochondrial structure and biogenesis with the concomitant activation of AMPK signaling. Augmented lipid peroxidation (LPO) in the presence of DOC2B was a Ca²⁺-dependent process. Our findings demonstrated that DOC2B promotes lipid accumulation, oxidative stress, and LPO through intracellular Ca²⁺ overload, which may contribute to mitochondrial dysfunction and tumor-suppressive properties of DOC2B. We propose that the DOC2B-Ca²⁺-oxidative stress-LPO-mitochondrial axis could be targeted for confining CC. Further, the induction of lipotoxicity in tumor cells by activating DOC2B could serve as a novel therapeutic approach in CC.

The genomic regulation of metastatic dormancy

The genomics and pathways governing metastatic dormancy are critically important drivers of long-term patient survival given the considerable portion of cancers that recur aggressively months to years after initial treatments. Our understanding of dormancy has expanded greatly in the last two decades, with studies elucidating that the dormant state is regulated by multiple genes, microenvironmental (ME) interactions, and immune components. These forces are exerted through mechanisms that are intrinsic to the tumor cell, manifested through cross-talk between tumor and ME cells including those from the immune system, and regulated by angiogenic processes in the nascent micrometastatic niche. The development of new in vivo and 3D ME models, as well as enhancements to decades-old tumor cell pedigree models that span the development of metastatic dormancy to aggressive growth, has helped fuel what arguably is one of the least understood areas of cancer biology that nonetheless contributes immensely to patient mortality. The current review focuses on the genes and molecular pathways that regulate dormancy via tumor-intrinsic and ME cells, and how groups have envisioned harnessing these therapeutically to benefit patient survival.

Cooperative NF-κB and Notch1 signaling promotes macrophage-mediated MenaINV expression in breast cancer

Metastasis is a multistep process that leads to the formation of clinically detectable tumor foci at distant organs and frequently patient demise. Only a subpopulation of breast cancer cells within the primary tumor can disseminate systemically and cause metastasis. To disseminate, cancer cells must express MenaINV, an isoform of the actin-regulatory protein Mena encoded by the ENAH gene that endows tumor cells with transendothelial migration activity allowing them to enter and exit the blood circulation. We have previously demonstrated that MenaINV mRNA and protein expression is induced in cancer cells by macrophage contact. In this study, we discovered the precise mechanism by which macrophages induce MenaINV expression in tumor cells. We examined the promoter of the human and mouse ENAH gene and discovered a conserved NF-κB transcription factor binding site. Using live imaging of an NF-κB activity reporter and staining of fixed tissues from mouse and human breast cancer we further determined that for maximal induction of MenaINV in cancer cell NF-κB needs to cooperate with the Notch1 signaling pathway. Mechanistically, Notch1 signaling does not directly increase MenaINV expression, but it enhances and sustains NF-κB signaling through retention of p65, an NF-κB transcription factor, in the nucleus of tumor cells, leading to increased MenaINV expression. In mice, these signals are augmented following chemotherapy treatment and abrogated upon macrophage depletion. Targeting Notch1 signaling in vivo decreased NF-κB signaling and MenaINV expression in the primary tumor and decreased metastasis. Altogether, these data uncover mechanistic targets for blocking MenaINV induction that should be explored clinically to decrease cancer cell dissemination and improve survival of patients with metastatic disease.

Pro- and anti-tumour activities of CD146/MCAM in breast cancer result from its heterogeneous expression and association with epithelial to mesenchymal transition

CD146, also known as melanoma cell adhesion molecule (MCAM), is expressed in numerous cancers and has been implicated in the regulation of metastasis. We show that CD146 negatively regulates transendothelial migration (TEM) in breast cancer. This inhibitory activity is reflected by a reduction in MCAM gene expression and increased promoter methylation in tumour tissue compared to normal breast tissue. However, increased CD146/MCAM expression is associated with poor prognosis in breast cancer, a characteristic that is difficult to reconcile with inhibition of TEM by CD146 and its epigenetic silencing. Single cell transcriptome data revealed MCAM expression in multiple cell types, including the malignant cells, tumour vasculature and normal epithelium. MCAM expressing malignant cells were in the minority and expression was associated with epithelial to mesenchymal transition (EMT). Furthermore, gene expression signatures defining invasiveness and a stem cell-like phenotype were most strongly associated with mesenchymal-like tumour cells with low levels of MCAM mRNA, likely to represent a hybrid epithelial/mesenchymal (E/M) state. Our results show that high levels of MCAM gene expression are associated with poor prognosis in breast cancer because they reflect tumour vascularisation and high levels of EMT. We suggest that high levels of mesenchymal-like malignant cells reflect large populations of hybrid E/M cells and that low CD146 expression on these hybrid cells is permissive for TEM, aiding metastasis.

Biological Screening of Polyphenol Derivatives for Anti-Proliferative, Anti-Apoptotic and Anti-Migrative Activities in Human Breast Cancer Cell Lines MCF-7

Breast cancer is known as the most common type of invasive cancer in women. It is well-known that phenolic compounds play an important role in the treatment of this disease. This study hypothesized that isoeugenol based two polyphenolic compounds 1 and 2 exerts its anti-proliferative effects through the induction of apoptosis and cell migration arrest on human breast cancer cell. Based on this hypothesis, the study aimed to investigate the anti-proliferative, anti-migrative effects of these compounds and their possible basic molecular mechanisms of action in MCF-7 cell lines. As a result, isoeugenol-based compounds 1 and 2 showed anti-proliferative, anti-apoptotic and anti-migrative effects in MCF-7 breast cancer cells. This result was supported by molecular analyzes and it was determined that there were changes in the expression of some gene regions involved in apoptosis and migration. Additionally, it was a remarkable result that cell viability inhibition did not occur in healthy breast tissue cells and no cytotoxic effect was observed. The existence of such a differentiation between cancer cells and healthy cells significantly increases the potential of these compounds to be used as chemotherapeutic drug active ingredients without side effects.

Investigating the Function of Human Jumping Translocation Breakpoint Protein (hJTB) and Its Interacting Partners through In-Solution Proteomics of MCF7 Cells

Human jumping translocation breakpoint (hJTB) gene is located on chromosome 1q21 and is involved in unbalanced translocation in many types of cancer. JTB protein is ubiquitously present in normal cells but it is found to be overexpressed or downregulated in various types of cancer cells, where this protein and its isoforms promote mitochondrial dysfunction, resistance to apoptosis, genomic instability, proliferation, invasion and metastasis. Hence, JTB could be a tumor biomarker for different types of cancer, such as breast cancer (BC), and could be used as a drug target for therapy. However, the functions of the protein or the pathways through which it increases cell proliferation and invasiveness of cancer cells are not well-known. Therefore, we aim to investigate the functions of JTB by using in-solution digestion-based cellular proteomics of control and upregulated and downregulated JTB protein in MCF7 breast cancer cell line, taking account that in-solution digestion-based proteomics experiments are complementary to the initial in-gel based ones. Proteomics analysis allows investigation of protein dysregulation patterns that indicate the function of the protein and its interacting partners, as well as the pathways and biological processes through which it functions. We concluded that JTB dysregulation increases the epithelial-mesenchymal transition (EMT) potential and cell proliferation, harnessing cytoskeleton organization, apical junctional complex, metabolic reprogramming, and cellular proteostasis. Deregulated JTB expression was found to be associated with several proteins involved in mitochondrial organization and function, oxidative stress (OS), apoptosis, and interferon alpha and gamma signaling. Consistent and complementary to our previous results emerged by using in-gel based proteomics of transfected MCF7 cells, JTB-related proteins that are overexpressed in this experiment suggest the development of a more aggressive phenotype and behavior for this luminal type A non-invasive/poor-invasive human BC cell line that does not usually migrate or invade compared with the highly metastatic MDA-MB-231 cells. This more aggressive phenotype of MCF7 cells related to JTB dysregulation and detected by both in-gel and in-solution proteomics could be promoted by synergistic upregulation of EMT, Mitotic spindle and Fatty acid metabolism pathways. However, in both JTB dysregulated conditions, several downregulated JTB-interacting proteins predominantly sustain antitumor activities, attenuating some of the aggressive phenotypical and behavioral traits promoted by the overexpressed JTB-related partners.

Reduced expression of FRG1 facilitates breast cancer progression via GM-CSF/MEK-ERK axis by abating FRG1 mediated transcriptional repression of GM-CSF

Multiple molecular subtypes and distinct clinical outcomes in breast cancer, necessitate specific therapy. Moreover, despite the improvements in breast cancer therapy, it remains the fifth cause of cancer-related deaths, indicating the involvement of unknown genes. To identify novel contributors and molecular subtype independent therapeutic options, we report reduced expression of FRG1 in breast cancer patients, which regulates GM-CSF expression via direct binding to its promoter. Reduction in FRG1 expression enhanced EMT and increased cell proliferation, migration, and invasion, in breast cancer cell lines. Loss of FRG1 increased GM-CSF levels which activated MEK/ERK axis and prevented apoptosis by inhibiting p53 in an ERK-dependent manner. FRG1 depletion in the mouse model increased tumor volume, phospho-ERK, and EMT marker levels. The therapeutic potential of anti-GM-CSF therapy was evident by reduced tumor size, when tumors with decreased FRG1 were treated with anti-GM-CSF mAb. We found an inverse expression pattern of FRG1 and phospho-ERK levels in breast cancer patient tissues, corroborating the in vitro and mouse model-based findings. Our findings first time elucidate the role of FRG1 as a metastatic suppressor of breast cancer by regulating the GM-CSF/MEK-ERK axis.

A proliferative to invasive switch is mediated by srGAP1 downregulation through the activation of TGF-β2 signaling

Many breast cancer (BC) patients suffer from complications of metastatic disease. To form metastases, cancer cells must become migratory and coordinate both invasive and proliferative programs at distant organs. Here, we identify srGAP1 as a regulator of a proliferative-to-invasive switch in BC cells. High-resolution light-sheet microscopy demonstrates that BC cells can form actin-rich protrusions during extravasation. srGA-P1^low cells display a motile and invasive phenotype that facilitates their extravasation from blood vessels, as shown in zebrafish and mouse models, while attenuating tumor growth. Interestingly, a population of srGAP1^low cells remain as solitary disseminated tumor cells in the lungs of mice bearing BC tumors. Overall, srGAP1^low cells have increased Smad2 activation and TGF-β2 secretion, resulting in increased invasion and p27 levels to sustain quiescence. These findings identify srGAP1 as a mediator of a proliferative to invasive phenotypic switch in BC cells in vivo through a TGF-β2-mediated signaling axis.

Disseminated tumor cells can remain quiescent or actively proliferate in distant organs, contributing to aggressive disease. Mondal et al. identify srGAP1 as a regulator of a proliferative-to-invasive decision by breast cancer (BC) cells through a TGF-β2-mediated signaling axis.

Suppression of OCT-1 in Metastatic Breast Cancer Cells Reduces Tumor Metastatic Potential, Hypoxia Resistance, and Drug Resistance

OCT-1/POU2F1 is a ubiquitously expressed transcription factor. Its expression starts at the earliest stage of embryonic development. OCT-1 controls genes involved in the regulation of differentiation, proliferation, cell metabolism, and aging. High levels of OCT-1 transcription factor in tumor cells correlate with tumor malignancy and resistance to antitumor therapy. Here, we report that suppression of OCT-1 in breast cancer cells reduces their metastatic potential and drug resistance. OCT-1 knockdown in the MDA-MB231 breast cancer cells leads to a fivefold decrease (p < 0.01) in cell migration rates in the Boyden chamber. A decrease in the transcription levels of human invasion signature (HIS) genes (ARHGDIB, CAPZA2, PHACTR2, CDC42, XRCC5, and CAV1) has been also demonstrated by real-time PCR, with high expression of these genes being a hallmark of actively metastasizing breast cancer cells. Transcriptional activity of ATF6 response elements is significantly reduced in the cell lines with decreased OCT-1 expression, which results in lower levels of adaptive EPR stress response. OCT-1 knockdown more than two times increases the MDA-MB231 cell death rate in hypoxia and significantly increases the doxorubicin or docetaxel-treated MDA-MB231 cell death rate. Our findings indicate that OCT-1 may be an important therapeutic target and its selective inhibition may have significant therapeutic effects and may improve prognosis in breast cancer patients.

Investigation of the effects of downregulation of jumping translocation breakpoint (JTB) protein expression in MCF7 cells for potential use as a biomarker in breast cancer

MCF7 is a commonly used luminal type A non-invasive/poor-invasive human breast cancer cell line that does not usually migrate or invade compared with MDA-MB-231 highly metastatic cells, which emphasize an invasive and migratory behavior. Under special conditions, MCF7 cells might acquire invasive features. The aberration in expression and biological functions of the jumping translocation breackpoint (JTB) protein is associated with malignant transformation of cells, based on mitochondrial dysfunction, inhibition of tumor suppressive function of TGF-β, and involvement in cancer cell cycle. To investigate new putative functions of JTB by cellular proteomics, we analyzed the biological processes and pathways that are associated with the JTB protein downregulation. The results demonstrated that MCF7 cell line developed a more "aggressive" phenotype and behavior. Most of the proteins that were overexpressed in this experiment promoted the actin cytoskeleton reorganization that is involved in growth and metastatic dissemination of cancer cells. Some of these proteins are involved in the epithelial-mesenchymal transition (EMT) process (ACTBL2, TUBA4A, MYH14, CSPG5, PKM, UGDH, HSP90AA2, and MIF), in correlation with the energy metabolism reprogramming (PKM, UGDH), stress-response (HSP10, HSP70A1A, HSP90AA2), and immune and inflammatory response (MIF and ERp57-TAPBP). Almost all upregulated proteins in JTB downregulated condition promote viability, motility, proliferation, invasion, survival into a hostile microenvironment, metabolic reprogramming, and escaping of tumor cells from host immune control, leading to a more invasive phenotype for MCF7 cell line. Due to their downregulated condition, four proteins, such as CREBZF, KMT2B, SELENOS and CACNA1I are also involved in maintenance of the invasive phenotype of cancer cells, promoting cell proliferation, migration, invasion and tumorigenesis. Other downregulated proteins, such as MAZ, PLEKHG2, ENO1, TPI2, TOR2A, and CNNM1, may promote suppression of cancer cell growth, invasion, EMT, tumorigenic abilities, interacting with glucose and lipid metabolism, disrupting nuclear envelope stability, or suppressing apoptosis and developing anti-angiogenetic activities. Therefore, the main biological processes and pathways that may increase the tumorigenic potential of the MCF7 cells in JTB downregulated condition are related to the actin cytoskeleton organization, EMT, mitotic cell cycle, glycolysis and fatty acid metabolism, inflammatory response and macrophage activation, chemotaxis and migration, cellular response to stress condition (oxidative stress and hypoxia), transcription control, histone modification and ion transport.

Assessment of MRI to estimate metastatic dissemination risk and prometastatic effects of chemotherapy

Metastatic dissemination in breast cancer is regulated by specialized intravasation sites called “tumor microenvironment of metastasis” (TMEM) doorways, composed of a tumor cell expressing the actin-regulatory protein Mena, a perivascular macrophage, and an endothelial cell, all in stable physical contact. High TMEM doorway number is associated with an increased risk of distant metastasis in human breast cancer and mouse models of breast carcinoma. Here, we developed a novel magnetic resonance imaging (MRI) methodology, called TMEM Activity-MRI, to detect TMEM-associated vascular openings that serve as the portal of entry for cancer cell intravasation and metastatic dissemination. We demonstrate that TMEM Activity-MRI correlates with primary tumor TMEM doorway counts in both breast cancer patients and mouse models, including MMTV-PyMT and patient-derived xenograft models. In addition, TMEM Activity-MRI is reduced in mouse models upon treatment with rebastinib, a specific and potent TMEM doorway inhibitor. TMEM Activity-MRI is an assay that specifically measures TMEM-associated vascular opening (TAVO) events in the tumor microenvironment, and as such, can be utilized in mechanistic studies investigating molecular pathways of cancer cell dissemination and metastasis. Finally, we demonstrate that TMEM Activity-MRI increases upon treatment with paclitaxel in mouse models, consistent with prior observations that chemotherapy enhances TMEM doorway assembly and activity in human breast cancer. Our findings suggest that TMEM Activity-MRI is a promising precision medicine tool for localized breast cancer that could be used as a non-invasive test to determine metastatic risk and serve as an intermediate pharmacodynamic biomarker to monitor therapeutic response to agents that block TMEM doorway-mediated dissemination.

Primary tumor associated macrophages activate programs of invasion and dormancy in disseminating tumor cells

Metastases are initiated by disseminated tumor cells (DTCs) that colonize distant organs. Growing evidence suggests that the microenvironment of the primary tumor primes DTCs for dormant or proliferative fates. However, the manner in which this occurs remains poorly understood. Here, using the Window for High-Resolution Intravital Imaging of the Lung (WHRIL), we study the live lung longitudinally and follow the fate of individual DTCs that spontaneously disseminate from orthotopic breast tumors. We find that spontaneously DTCs have increased levels of retention, increased speed of extravasation, and greater survival after extravasation, compared to experimentally metastasized tumor cells. Detailed analysis reveals that a subset of macrophages within the primary tumor induces a pro-dissemination and pro-dormancy DTC phenotype. Our work provides insight into how specific primary tumor microenvironments prime a subpopulation of cells for expression of proteins associated with dissemination and dormancy.

Decoding Single Cell Morphology in Osteotropic Breast Cancer Cells for Dissecting Their Migratory, Molecular and Biophysical Heterogeneity

Breast cancer is a heterogeneous disease and the mechanistic framework for differential osteotropism among intrinsic breast cancer subtypes is unknown. Hypothesizing that cell morphology could be an integrated readout for the functional state of a cancer cell, we established a catalogue of the migratory, molecular and biophysical traits of MDA-MB-231 breast cancer cells, compared it with two enhanced bone-seeking derivative cell lines and integrated these findings with single cell morphology profiles. Such knowledge could be essential for predicting metastatic capacities in breast cancer. High-resolution microscopy revealed a heterogeneous and specific spectrum of single cell morphologies in bone-seeking cells, which correlated with differential migration and stiffness. While parental MDA-MB-231 cells showed long and dynamic membrane protrusions and were enriched in motile cells with continuous and mesenchymal cell migration, bone-seeking cells appeared with discontinuous mesenchymal or amoeboid-like migration. Although non-responsive to CXCL12, bone-seeking cells responded to epidermal growth factor with a morphotype shift and differential expression of genes controlling cell shape and directional migration. Hence, single cell morphology encodes the molecular, migratory and biophysical architecture of breast cancer cells and is specifically altered among osteotropic phenotypes. Quantitative morpho-profiling could aid in dissecting breast cancer heterogeneity and in refining clinically relevant intrinsic breast cancer subtypes.

Weakly migratory metastatic breast cancer cells activate fibroblasts via microvesicle-Tg2 to facilitate dissemination and metastasis

Cancer cell migration is highly heterogeneous, and the migratory capability of cancer cells is thought to be an indicator of metastatic potential. It is becoming clear that a cancer cell does not have to be inherently migratory to metastasize, with weakly migratory cancer cells often found to be highly metastatic. However, the mechanism through which weakly migratory cells escape from the primary tumor remains unclear. Here, utilizing phenotypically sorted highly and weakly migratory human breast cancer cells, we demonstrate that weakly migratory metastatic cells disseminate from the primary tumor via communication with stromal cells. While highly migratory cells are capable of single cell migration, weakly migratory cells rely on cell-cell signaling with fibroblasts to escape the primary tumor. Weakly migratory cells release microvesicles rich in tissue transglutaminase 2 (Tg2) which activate murine fibroblasts and lead weakly migratory cancer cell migration in vitro. These microvesicles also induce tumor stiffening and fibroblast activation in vivo and enhance the metastasis of weakly migratory cells. Our results identify microvesicles and Tg2 as potential therapeutic targets for metastasis and reveal a novel aspect of the metastatic cascade in which weakly migratory cells release microvesicles which activate fibroblasts to enhance cancer cell dissemination.

Invadopodia, a Kingdom of Non-Receptor Tyrosine Kinases

Non-receptor tyrosine kinases (NRTKs) are crucial mediators of intracellular signaling and control a wide variety of processes such as cell division, morphogenesis, and motility. Aberrant NRTK-mediated tyrosine phosphorylation has been linked to various human disorders and diseases, among them cancer metastasis, to which no treatment presently exists. Invasive cancer cells leaving the primary tumor use invadopodia, feet-like structures which facilitate extracellular matrix (ECM) degradation and intravasation, to escape the primary tumor and disseminate into distant tissues and organs during metastasis. A major challenge in metastasis research is to elucidate the molecular mechanisms and signaling pathways underlying invadopodia regulation, as the general belief is that targeting these structures can potentially lead to the eradication of cancer metastasis. Non-receptor tyrosine kinases (NRTKs) play a central role in regulating invadopodia formation and function, but how they coordinate the signaling leading to these processes was not clear until recently. Here, we describe the major NRTKs that rule invadopodia and how they work in concert while keeping an accurate hierarchy to control tumor cell invasiveness and dissemination.

Invasion and Metastasis as a Central Hallmark of Breast Cancer

Hanahan and Weinberg introduced the "hallmarks of cancer" and typified essential biological abilities acquired by human cancer. Since then, a growing understanding of hallmark principles associated with breast cancer has assisted knowledge-based therapeutics development; however, despite the rapidly increasing number of targeted therapeutics, enduring disease-free responses for most forms of breast cancer is rare. Invasion and metastasis are the most defining feature of breast cancer malignancy and the leading cause of patient mortality. Hence, we propose a modified hallmarks model adapted to breast cancer, in which invasion and metastasis are shifted to the center of attention, thereby emphasizing it as a potentially superior therapeutic target. Although the scientific community highly appreciates the importance of the invasion and metastasis hallmark, as can be demonstrated by the growing number of publications on breast cancer metastasis, very few clinical trials concentrate on testing anti-metastasis inhibitors and even fewer trials focus on inhibitors for breast cancer metastasis. Here, we discuss the obstacles of applying research on invasion and metastasis therapeutics into the clinic and present current developments that could provide a potential solution to this dilemma.

Combining gene expression signature with clinical features for survival stratification of gastric cancer

The AJCC staging system is considered as the golden standard in clinical practice. However, it remains some pitfalls in assessing the prognosis of gastric cancer (GC) patients with similar clinicopathological characteristics. We aim to develop a new clinic and genetic risk score (CGRS) to improve the prognosis prediction of GC patients. We established genetic risk score (GRS) based on nine-gene signature including APOD, CCDC92, CYS1, GSDME, ST8SIA5, STARD3NL, TIMEM245, TSPYL5, and VAT1 based on the gene expression profiles of the training set from the Asian Cancer Research Group (ACRG) cohort by LASSO-Cox regression algorithms. CGRS was established by integrating GRS with clinical risk score (CRS) derived from Surveillance, Epidemiology, and End Results (SEER) database. GRS and CGRS dichotomized GC patients into high and low risk groups with significantly different prognosis in four independent cohorts with different data types, such as microarray, RNA sequencing and qRT-PCR (all HR > 1, all P < 0.001). Both GRS and CGRS were prognostic signatures independent of the AJCC staging system. Receiver operating characteristic (ROC) analysis showed that area under ROC curve of CGRS was larger than that of the AJCC staging system in most cohorts we studied. Nomogram and web tool (http://39.100.117.92/CGRS/) based on CGRS were developed for clinicians to conveniently assess GC prognosis in clinical practice. CGRS integrating genetic signature with clinical features shows strong robustness in predicting GC prognosis, and can be easily applied in clinical practice through the web application.

A Method to Pre-Screen Rat Mammary Gland Whole-Mounts Prior To RNAscope

RNAscope is a quantitative in situ gene expression measurement technique that preserves the spatial aspect of intact tissue; thus, allowing for comparison of specific cell populations and morphologies. Reliable and accurate measurement of gene expression in tissue is dependent on preserving RNA integrity and the quantitative nature of RNAscope. The purpose of this study was to determine if the quantitative nature of RNAscope was retained following processing and carmine staining of mammary gland whole-mounts, which are commonly used to identify lesions, such as hyperplasia and ductal carcinoma in situ (DCIS). We were concerned that handling and procedures required to visualize microscopic disease lesions might compromise RNA integrity and the robustness of RNAscope. No effect on the quantitative abilities of RNAscope was detected when mammary gland whole-mounts were pre-screened for lesions of interest prior to RNAscope. This was determined in comparison to tissue that had been formalin-fixed and paraffin embedded (FFPE) immediately after collection. The ability to pre-screen whole-mounts allowed unpalpable diseased lesions to be identified without labor-intensive serial sectioning of tissue samples to find diseased tissue. This method is applicable to evaluate mammary gland whole-mounts during normal mammary gland development, function, and disease progression.

Tejaas: reverse regression increases power for detecting trans-eQTLs

Trans-acting expression quantitative trait loci (trans-eQTLs) account for ≥70% expression heritability and could therefore facilitate uncovering mechanisms underlying the origination of complex diseases. Identifying trans-eQTLs is challenging because of small effect sizes, tissue specificity, and a severe multiple-testing burden. Tejaas predicts trans-eQTLs by performing L2-regularized “reverse” multiple regression of each SNP on all genes, aggregating evidence from many small trans-effects while being unaffected by the strong expression correlations. Combined with a novel unsupervised k-nearest neighbor method to remove confounders, Tejaas predicts 18851 unique trans-eQTLs across 49 tissues from GTEx. They are enriched in open chromatin, enhancers, and other regulatory regions. Many overlap with disease-associated SNPs, pointing to tissue-specific transcriptional regulation mechanisms.

Metastatic suppression by DOC2B is mediated by inhibition of epithelial-mesenchymal transition and induction of senescence

Senescence induction and epithelial-mesenchymal transition (EMT) events are the opposite sides of the spectrum of cancer phenotypes. The key molecules involved in these processes may get influenced or altered by genetic and epigenetic changes during tumor progression. Double C2-like domain beta (DOC2B), an intracellular vesicle trafficking protein of the double C2 protein family, plays a critical role in exocytosis, neurotransmitter release, and intracellular vesicle trafficking. DOC2B is repressed by DNA promoter hypermethylation and functions as a tumor growth regulator in cervical cancer. To date, the molecular mechanisms of DOC2B in cervical cancer progression and metastasis is elusive. Herein, the biological functions and molecular mechanisms regulated by DOC2B and its impact on senescence and EMT are described. DOC2B inhibition promotes proliferation, growth, and migration by relieving G0/G1-S arrest, actin remodeling, and anoikis resistance in Cal27 cells. It enhanced tumor growth and liver metastasis in nude mice with the concomitant increase in metastasis-associated CD55 and CD61 expression. Inhibition of EMT and promotion of senescence by DOC2B is a calcium-dependent process and accompanied by calcium-mediated interaction between DOC2B and CDH1. In addition, we have identified several EMT and senescence regulators as targets of DOC2B. We show that DOC2B may act as a metastatic suppressor by inhibiting EMT through induction of senescence via DOC2B-calcium-EMT-senescence axis.

Interception Targets of Angelica Gigas Nakai Root Extract versus Pyranocoumarins in Prostate Early Lesions and Neuroendocrine Carcinomas in TRAMP Mice

We reported efficacy of Angelica gigas Nakai (AGN) root ethanol extract and equimolar decursin (D)/decursinol angelate (DA) through daily gavage starting at 8 weeks of age (WOA) to male transgenic adenocarcinoma of mouse prostate (TRAMP) mice such that these modalities suppressed precancerous epithelial lesions in their dorsolateral prostate (DLP) to similar extent, but AGN extract was better than the D/DA mixture at promoting the survival of mice bearing prostate neuroendocrine carcinomas to 28 WOA. Here, we compared by microarray hybridization the mRNA levels in pooled DLP tissues and individual neuroendocrine carcinomas to characterize potential molecular targets of AGN extract and D/DA. Clustering and principal component analyses supported distinct gene expression profiles of TRAMP DLP versus neuroendocrine carcinomas. Pathway Enrichment, Gene Ontology, and Ingenuity Pathway Analyses of differential genes indicated that AGN and D/DA affected chiefly processes of lipid and mitochondrial energy metabolism and oxidation-reduction in TRAMP DLP, while AGN affected neuronal signaling, immune systems and cell cycling in neuroendocrine carcinomas. Protein-Protein Interaction Network analysis predicted and reverse transcription-PCR verified multiple hub genes common in the DLP of AGN- and D/DA-treated TRAMP mice at 28 WOA and select hub genes attributable to the non-D/DA AGN components. The vast majority of hub genes in the AGN-treated neuroendocrine carcinomas differed from those in TRAMP DLP. In summary, the transcriptomic approach illuminated vastly different signaling pathways and networks, cellular processes, and hub genes of two TRAMP prostate malignancy lineages and their associations with the interception efficacy of AGN and D/DA. PREVENTION RELEVANCE: This study explores potential molecular targets associated with in vivo activity of AGN root alcoholic extract and its major pyranocoumarins to intercept precancerous epithelial lesions and early malignancies of the prostate. Without an ethically-acceptable, clearly defined cancer initiation risk reduction strategy available for the prostate, using natural products like AGN to delay formation of malignant tumors could be a plausible approach for prostate cancer prevention.

A 23-gene prognostic classifier for prediction of recurrence and survival for Asian breast cancer patients

We report a 23- gene-classifier profiled from Asian women, with the primary purpose of assessing its clinical utility towards improved risk stratification for relapse for breast cancer patients from Asian cohorts within 10 years’ following mastectomy. Four hundred and twenty-two breast cancer patients underwent mastectomy and were used to train the classifier on a logistic regression model. A subset of 197 patients were chosen to be entered into the follow-up studies post mastectomy who were examined to determine the patterns of recurrence and survival analysis based on gene expression of the gene classifier, age at diagnosis, tumor stage and lymph node status, over a 5 and 10 years follow-up period. Metastasis to lymph node (N2-N3) with N0 as the reference (N2 vs. N0 hazard ratio: 2.02 (1.05–8.70), N3 vs. N0 hazard ratio: 4.32 (1.41–13.22) for 5 years) and gene expression of the 23-gene panel (P=0.06, 5 years and 0.02, 10 years, log-rank test) were found to have significant discriminatory effects on the risk of relapse (HR (95%CI):2.50 (0.95–6.50)). Furthermore, survival curves for subgroup analysis with N0-N1 and T1-T2 predicted patients with higher risk scores. The study provides robust evidence of the effectiveness of the 23-gene-classifier and could be used to determine the risk of relapse event (locoregional and distant recurrence) in Asian patients, leading to a meaningful reduction in chemotherapy recommendations.

Two high-yield complementary methods to sort cell populations by their 2D or 3D migration speed

The potential to migrate is one of the most fundamental functions for various epithelial, mesenchymal, and immune cells. Image analysis of motile cell populations, both primary and cultured, typically reveals an intercellular variability in migration speeds. However, cell migration chromatography, the sorting of large populations of cells based on their migratory characteristics, cannot be easily performed. The lack of such methods has hindered our understanding of the direct correlation between the capacity to migrate and other cellular properties. Here, we report two novel, easily implementable and readily scalable methods to sort millions of live migratory cancer and immune cells based on their spontaneous migration in two-dimensional and three-dimensional microenvironments, respectively. Correlative downstream transcriptomic, molecular and functional tests reveal marked differences between the fast and slow subpopulations in patient-derived cancer cells. We further employ our method to reveal that sorting the most migratory cytotoxic T lymphocytes yields a pool of cells with enhanced cytotoxicity against cancer cells. This phenotypic assay opens new avenues for the precise characterization of the mechanisms underlying hither to unexplained heterogeneities in migratory phenotypes within a cell population, and for the targeted enrichment of the most potent migratory leukocytes in immunotherapies.

Breast cancer-associated macrophages promote tumorigenesis by suppressing succinate dehydrogenase in tumor cells

Tumor-associated macrophages (TAMs) can exist in pro- and anti-inflammatory states. Anti-inflammatory TAMs (also referred to as M2-polarized) generally suppress antitumor immune responses and enhance the metastatic progression of cancer. To explore the mechanisms behind this phenomenon, we isolated macrophages from mice and humans, polarized them ex vivo, and examined their functional interaction with breast cancer cells in culture and in mice. We found that anti-inflammatory TAMs promoted a metabolic state in breast cancer cells that supported various protumorigenic phenotypes. Anti-inflammatory TAMs secreted the cytokine TGF-β that, upon engagement of its receptors in breast cancer cells, suppressed the abundance of the transcription factor STAT1 and, consequently, decreased that of the metabolic enzyme succinate dehydrogenase (SDH) in the tumor cells. The decrease in SDH levels in tumor cells resulted in an accumulation of succinate, which enhanced the stability of the transcription factor HIF1α and reprogrammed cell metabolism to a glycolytic state. TAM depletion-repletion experiments in a 4T1 mouse model additionally revealed that anti-inflammatory macrophages promoted HIF-associated vascularization and expression of the immunosuppressive protein PD-L1 in tumors. The findings suggest that anti-inflammatory TAMs promote tumor-associated angiogenesis and immunosuppression by altering metabolism in breast cancer cells.

Senescence-Associated Pro-inflammatory Cytokines and Tumor Cell Plasticity

The well-recognized cell phenotypic heterogeneity in tumors is a great challenge for cancer treatment. Dynamic interconversion and movement within a spectrum of different cell phenotypes (cellular plasticity) with the acquisition of specific cell functions is a fascinating biological puzzle, that represent an additional difficulty for cancer treatment and novel therapies development. The understanding of the molecular mechanisms responsible for moving or stabilizing tumor cells within this spectrum of variable states constitutes a valuable tool to overcome these challenges. In particular, cell transitions between epithelial and mesenchymal phenotypes (EMT-MET) and de-and trans-differentiation processes are relevant, since it has been shown that they confer invasiveness, drug resistance, and metastatic ability, due to the simultaneous acquisition of stem-like cell properties. Multiple drivers participate in these cell conversions events. In particular, cellular senescence and senescence-associated soluble factors have been shown to unveil stem-like cell properties and cell plasticity. By modulating gradually the composition of their secretome and the time of exposure, senescent cells may have differential effect not only on tumor cells but also on surrounding cells. Intriguingly, tumor cells that scape from senescence acquire stem-like cell properties and aggressiveness. The reinforcement of senescence and inflammation by soluble factors and the participation of immune cells may provide a dynamic milieu having varied effects on cell transitions, reprogramming, plasticity, stemness and therefore heterogeneity. This will confer different epithelial/mesenchymal traits (hybrid phenotype) and stem-like cell properties, combinations of which, in a particular cell context, could be responsible for different cellular functions during cancer progression (survival, migration, invasion, colonization or proliferation). Additionally, cooperative behavior between cell subpopulations with different phenotypes/stemness functions could also modulate their cellular plasticity. Here, we will discuss the role of senescence and senescence-associated pro-inflammatory cytokines on the induction of cellular plasticity, their effect role in establishing particular states within this spectrum of cell phenotypes and how this is accompanied by stem-like cell properties that, as the epithelial transitions, may also have a continuum of characteristics providing tumor cells with functional adaptability specifically useful in the different stages of carcinogenesis.

A small-molecule allosteric inhibitor of BAX protects against doxorubicin-induced cardiomyopathy

Doxorubicin remains an essential component of many cancer regimens, but its use is limited by lethal cardiomyopathy, which has been difficult to target, owing to pleiotropic mechanisms leading to apoptotic and necrotic cardiac cell death. Here we show that BAX is rate-limiting in doxorubicin-induced cardiomyopathy and identify a small-molecule BAX inhibitor that blocks both apoptosis and necrosis to prevent this syndrome. By allosterically inhibiting BAX conformational activation, this compound blocks BAX translocation to mitochondria, thereby abrogating both forms of cell death. When co-administered with doxorubicin, this BAX inhibitor prevents cardiomyopathy in zebrafish and mice. Notably, cardioprotection does not compromise the efficacy of doxorubicin in reducing leukemia or breast cancer burden in vivo, primarily due to increased priming of mitochondrial death mechanisms and higher BAX levels in cancer cells. This study identifies BAX as an actionable target for doxorubicin-induced cardiomyopathy and provides a prototype small-molecule therapeutic.

Possible Prognostic Potential of RANKL and OPG in Metastatic Breast Cancer Egyptian Females

Objectives:

Searching for sensitive, minimally invasive biomarkers that represent tumor-associated changes in the peripheral blood might enable the early diagnosis of breast cancer (BC) and monitoring of tumor progression.

Methods:

Herein, we investigated the association of some circulating biomarkers with the risk of metastasis. In the current study, 115 BC patients which were subdivided into two groups: nonmetastatic breast cancer patients (NMBC) (n=83) and metastatic breast cancer patients (MBC) (n=32), and 79 apparently healthy controls were recruited. Serum protein levels of lysosomal protein transmembrane 4 beta (LAPTM4B), receptor activator of nuclear factor-kappa b (NF-Kb) ligand (RANKL), osteoprotegerin (OPG), vitamin D (VIT D), chitinase-3-like protein 1 (also known as YKL-40), and sirtuin 1 (SIRT1) were assessed in blood samples using ELISA technique.

Results:

The results showed that RANKL and OPG had the highest diagnostic potential for MBC detection, with area under the curve values of 0.97 and 0.94, respectively. Moreover, logistic regression analysis showed that RANKL had the highest differentiation power in the discrimination of MBC from NMBC.

Conclusion:

The study highlighted that measuring RANKL and OPG may be helpful in the early detection of metastasis in Egyptian patients with BC.

Nucleolar stress regulation of endometrial receptivity in mouse models and human cell lines

Embryo implantation is essential to the successful establishment of pregnancy. A previous study has demonstrated that actinomycin D (ActD) could initiate the activation of mouse delayed implantation. However, the mechanism underlying this activation remains to be elucidated. A low dose of ActD is an inducer of nucleolar stress. This study was to examine whether nucleolar stress is involved in embryo implantation. We showed that nucleolar stress occurred when delayed implantation was activated by ActD in mice. ActD treatment also stimulated the Lif-STAT3 pathway. During early pregnancy, nucleolar stress was detected in the luminal epithelial cells during the receptive phase. Blastocyst-derived lactate could induce nucleolar stress in cultured luminal epithelial cells. The inhibition of nucleophosmin1 (NPM1), which was a marker of nucleolar stress, compromised uterine receptivity and decreased the implantation rates in pregnant mice. To translate these mouse data into humans, we examined nucleolar stress in human endometrium. Our data demonstrated that ActD-induced nucleolar stress had positive effects on the embryo attachment by upregulating IL32 expression in non-receptive epithelial cells rather than receptive epithelial cells. Our data should be the first to demonstrate that nucleolar stress is present during early pregnancy and is able to induce embryo implantation in both mice and humans.

Identification of Alternatively-Activated Pathways between Primary Breast Cancer and Liver Metastatic Cancer Using Microarray Data

Alternatively-activated pathways have been observed in biological experiments in cancer studies, but the concept had not been fully explored in computational cancer system biology. Therefore, an alternatively-activated pathway identification method was proposed and applied to primary breast cancer and breast cancer liver metastasis research using microarray data. Interestingly, the results show that cytokine-cytokine receptor interaction and calcium signaling were significantly enriched under both conditions. TGF beta signaling was found to be the hub in network topology analysis. In total, three types of alternatively-activated pathways were recognized. In the cytokine-cytokine receptor interaction pathway, four active alteration patterns in gene pairs were noticed. Thirteen cytokine-cytokine receptor pairs with inverse activity changes of both genes were verified by the literature. The second type was that some sub-pathways were active under only one condition. For the third type, nodes were significantly active in both conditions, but with different active genes. In the calcium signaling and TGF beta signaling pathways, node E2F5 and E2F4 were significantly active in primary breast cancer and metastasis, respectively. Overall, our study demonstrated the first time using microarray data to identify alternatively-activated pathways in breast cancer liver metastasis. The results showed that the proposed method was valid and effective, which could be helpful for future research for understanding the mechanism of breast cancer metastasis.

Prognostic value of biomarkers EpCAM and αB-crystallin associated with lymphatic metastasis in breast cancer by iTRAQ analysis

Background

Metastasis is responsible for the majority of deaths in a variety of cancer types, including breast cancer. Although several factors or biomarkers have been identified to predict the outcome of patients with breast cancer, few studies have been conducted to identify metastasis-associated biomarkers.

Methods

Quantitative iTRAQ proteomics analysis was used to detect differentially expressed proteins between lymph node metastases and their paired primary tumor tissues from 23 patients with metastatic breast cancer. Immunohistochemistry was performed to validate the expression of two upregulated (EpCAM, FADD) and two downregulated (NDRG1, αB-crystallin) proteins in 190 paraffin-embedded tissue samples. These four proteins were further analyzed for their correlation with clinicopathological features in 190 breast cancer patients.

Results

We identified 637 differentially regulated proteins (397 upregulated and 240 downregulated) in lymph node metastases compared with their paired primary tumor tissues. Data are available via ProteomeXchange with identifier PXD013931. Furthermore, bioinformatics analysis using GEO profiling confirmed the difference in the expression of EpCAM between metastases and primary tumors tissues. Two upregulated (EpCAM, FADD) and two downregulated (NDRG1, αB-crystallin) proteins were associated with the progression of breast cancer. Obviously, EpCAM plays a role in the metastasis of breast cancer cells to the lymph node. We further identified αB-crystallin as an independent biomarker to predict lymph node metastasis and the outcome of breast cancer patients.

Conclusion

We have identified that EpCAM plays a role in the metastasis of breast cancer cells to the lymph node. αB-crystallin, a stress-related protein that has recently been shown to be important for cell invasion and survival, was identified as a potential prognostic biomarker to predict the outcome of breast cancer patients.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-6016-3) contains supplementary material, which is available to authorized users.

Uncovering the signaling landscape controlling breast cancer cell migration identifies novel metastasis driver genes

Ttriple-negative breast cancer (TNBC) is an aggressive and highly metastatic breast cancer subtype. Enhanced TNBC cell motility is a prerequisite of TNBC cell dissemination. Here, we apply an imaging-based RNAi phenotypic cell migration screen using two highly motile TNBC cell lines (Hs578T and MDA-MB-231) to provide a repository of signaling determinants that functionally drive TNBC cell motility. We have screened ~4,200 target genes individually and discovered 133 and 113 migratory modulators of Hs578T and MDA-MB-231, respectively, which are linked to signaling networks predictive for breast cancer progression. The splicing factors PRPF4B and BUD31 and the transcription factor BPTF are essential for cancer cell migration, amplified in human primary breast tumors and associated with metastasis-free survival. Depletion of PRPF4B, BUD31 and BPTF causes primarily down regulation of genes involved in focal adhesion and ECM-interaction pathways. PRPF4B is essential for TNBC metastasis formation in vivo, making PRPF4B a candidate for further drug development.

Triple-negative breast cancers (TNBC) have enhanced migratory behaviour. Here, the authors perform a phenotypic imaging-based RNAi screen to identify several genes associated with regulation of migratory phenotypes and show that one of the regulators, PRPF4B, mediates metastasis in TNBC in mice.

Quantifying Cancer Epithelial-Mesenchymal Plasticity and its Association with Stemness and Immune Response

Cancer cells can acquire a spectrum of stable hybrid epithelial/mesenchymal (E/M) states during epithelial-mesenchymal transition (EMT). Cells in these hybrid E/M phenotypes often combine epithelial and mesenchymal features and tend to migrate collectively commonly as small clusters. Such collectively migrating cancer cells play a pivotal role in seeding metastases and their presence in cancer patients indicates an adverse prognostic factor. Moreover, cancer cells in hybrid E/M phenotypes tend to be more associated with stemness which endows them with tumor-initiation ability and therapy resistance. Most recently, cells undergoing EMT have been shown to promote immune suppression for better survival. A systematic understanding of the emergence of hybrid E/M phenotypes and the connection of EMT with stemness and immune suppression would contribute to more effective therapeutic strategies. In this review, we first discuss recent efforts combining theoretical and experimental approaches to elucidate mechanisms underlying EMT multi-stability (i.e., the existence of multiple stable phenotypes during EMT) and the properties of hybrid E/M phenotypes. Following we discuss non-cell-autonomous regulation of EMT by cell cooperation and extracellular matrix. Afterwards, we discuss various metrics that can be used to quantify EMT spectrum. We further describe possible mechanisms underlying the formation of clusters of circulating tumor cells. Last but not least, we summarize recent systems biology analysis of the role of EMT in the acquisition of stemness and immune suppression.

Reduced FRG1 expression promotes prostate cancer progression and affects prostate cancer cell migration and invasion

BACKGROUND

Prostate cancer is the most common form of cancer in males and accounts for high cancer related deaths. Therapeutic advancement in prostate cancer has not been able to reduce the mortality burden of prostate cancer, which warrants further research. FRG1 which affects angiogenesis and cell migration in Xenopus, can be a potential player in tumorigenesis. In this study, we investigated the role of FRG1 in prostate cancer progression.

METHODS

Immunohistochemistry was performed to determine FRG1 expression in patient samples. FRG1 expression perturbation was done to investigate the effect of FRG1 on cell proliferation, migration and invasion, in DU145, PC3 and LNCaP cells. To understand the mechanism, we checked expression of various cytokines and MMPs by q-RT PCR, signaling molecules by western blot, in FRG1 perturbation sets. Results were validated by use of pharmacological inhibitor and activator and, western blot.

RESULTS

In prostate cancer tissue, FRG1 levels were significantly reduced, compared to the uninvolved counterpart. FRG1 expression showed variable effect on PC3 and DU145 cell proliferation. FRG1 levels consistently affected cell migration and invasion, in both DU145 and PC3 cells. Ectopic expression of FRG1 led to significant reduction in cell migration and invasion in both DU145 and PC3 cells, reverse trends were observed with FRG1 knockdown. In androgen receptor positive cell line LNCaP, FRG1 doesn't affect any of the cell properties. FRG1 knockdown led to significantly enhanced expression of GM-CSF, MMP1, PDGFA and CXCL1, in PC3 cells and, in DU145, it led to higher expression of GM-CSF, MMP1 and PLGF. Interestingly, FRG1 knockdown in both the cell lines led to activation of p38 MAPK. Pharmacological activation of p38 MAPK led to increase in the expression of GM-CSF and PLGF in DU145 whereas in PC3 it led to enhanced expression of GM-CSF, MMP1 and CXCL1. On the other hand, inhibition of p38 MAPK led to reduction in the expression of above mentioned cytokines.

CONCLUSION

FRG1 expression is reduced in prostate adenocarcinoma tissue. FRG1 expression affects migration and invasion in AR negative prostate cancer cells through known MMPs and cytokines, which may be mediated primarily via p38 MAPK activation.

The emerging roles of macrophages in cancer metastasis and response to chemotherapy

Macrophages represent a heterogeneous group of cells, capable of carrying out distinct functions in a variety of organs and tissues. Even within individual tissues, their functions can vary with location. Tumor-associated macrophages (TAMs) specialize into three major subtypes that carry out multiple tasks simultaneously. This is especially true in the context of metastasis, where TAMs establish most of the cellular and molecular prerequisites for successful cancer cell dissemination and seeding to the secondary site. Perivascular TAMs operate in the perivascular niche, where they promote tumor angiogenesis and aid in the assembly of intravasation sites called tumor microenvironment of metastasis (TMEM). Streaming TAMs co-migrate with tumor cells (irrespective of the perivascular niche) and promote matrix remodeling, tumor cell invasiveness, and an immunosuppressive local microenvironment. Premetastatic TAMs are recruited to the premetastatic niche, where they can assist in tumor cell extravasation, seeding, and metastatic colonization. The dynamic interplay between TAMs and tumor cells can also modify the ability of the latter to resist cytotoxic chemotherapy (a phenotype known as environment-mediated drug resistance) and induce chemotherapy-mediated pro-metastatic microenvironmental changes. These observations suggest that future therapeutics should be designed to target TAMs with the aim of suppressing the metastatic potential of tumors and rendering chemotherapy more efficient.

Profiling of Invasive Breast Carcinoma Circulating Tumour Cells-Are We Ready for the 'Liquid' Revolution?

As dissemination through blood and lymph is the critical step of the metastatic cascade, circulating tumour cells (CTCs) have attracted wide attention as a potential surrogate marker to monitor progression into metastatic disease and response to therapy. In patients with invasive breast carcinoma (IBC), CTCs are being considered nowadays as a valid counterpart for the assessment of known prognostic and predictive factors. Molecular characterization of CTCs using protein detection, genomic and transcriptomic panels allows to depict IBC biology. Such molecular profiling of circulating cells with increased metastatic abilities appears to be essential, especially after tumour resection, as well as in advanced disseminated disease, when information crucial for identification of therapeutic targets becomes unobtainable from the primary site. If CTCs are truly representative of primary tumours and metastases, characterization of the molecular profile of this easily accessible ‘biopsy’ might be of prime importance for clinical practice in IBC patients. This review summarizes available data on feasibility and documented benefits of monitoring of essential IBC biological features in CTCs, with special reference to multifactorial proteomic, genomic, and transcriptomic panels of known prognostic or predictive value.

PIWI-interacting RNA-36712 restrains breast cancer progression and chemoresistance by interaction with SEPW1 pseudogene SEPW1P RNA

Background

Breast cancer is one of the most common malignancies and the major cause of cancer-related death in women. Although the importance of PIWI-interacting RNAs (piRNAs) in cancer has been increasingly recognized, few studies have been explored the functional mechanism of piRNAs in breast cancer development and progression.

Methods

We examined the top 20 highly expressed piRNAs based on the analysis of TCGA breast cancer data in two patient cohorts to test the roles of piRNAs in breast cancer. The effects of piRNA-36,712 on the malignant phenotypes and chemosensitivity of breast cancer cells were detected in vitro and in vivo. MS2-RIP and reporter gene assays were conducted to identify the interaction and regulation among piRNA-36,712, miRNAs and SEPW1P. Kaplan-Meier estimate with log-rank test was used to compare patient survival by different piRNA-36,712 expression levels.

Results

We found piRNA-36,712 level was significantly lower in breast cancer than in normal breast tissues and low level was correlated with poor clinical outcome in patients. Functional studies demonstrated that piRNA-36,712 interacts with RNAs produced by SEPW1P, a retroprocessed pseudogene of SEPW1, and subsequently inhibits SEPW1 expression through competition of SEPW1 mRNA with SEPW1P RNA for microRNA-7 and microRNA-324. We also found that higher SEPW1 expression due to downregulation of piRNA-36,712 in breast cancer may suppress P53, leading to the upregulated Slug but decreased P21 and E-cadherin levels, thus promoting cancer cell proliferation, invasion and migration. Furthermore, we found that piRNA-36,712 had synergistic anticancer effects with the paclitaxel and doxorubicin, two chemotherapeutic agents for breast cancer.

Conclusions

These findings suggest that piRNA-36,712 is a novel tumor suppressor and may serve as a potential predictor for the prognosis of breast cancer patients.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-0940-3) contains supplementary material, which is available to authorized users.

A systematic review of the validity of patient derived xenograft (PDX) models: the implications for translational research and personalised medicine

Patient-derived xenograft (PDX) models are increasingly being used in oncology drug development because they offer greater predictive value than traditional cell line models. Using novel tools to critique model validity and reliability we performed a systematic review to identify all original publications describing the derivation of PDX models of colon, prostate, breast and lung cancer. Validity was defined as the ability to recapitulate the disease of interest. The study protocol was registered with the Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies (CAMARADES). Searches were performed in Embase, MEDLINE and Pubmed up to July 2017. A narrative data synthesis was performed. We identified 105 studies of model validations; 29 for breast, 29 for colon, 25 for lung, 23 for prostate and 4 for multiple tissues. 133 studies were excluded because they did not perform any validation experiments despite deriving a PDX. Only one study reported following the ARRIVE guidelines; developed to improve the standard of reporting for animal experimentation. Remarkably, half of all breast (52%) and prostate (50%) studies were judged to have high concern, in contrast to 16% of colon and 28% of lung studies. The validation criteria that most commonly failed (evidence to the contrary) were: tissue of origin not proven and histology of the xenograft not comparable to the parental tumour. Overall, most studies were categorized as unclear because one or more validation conditions were not reported, or researchers failed to provide data for a proportion of their models. For example, failure to demonstrate tissue of origin, response to standard of care agents and to exclude development of lymphoma. Validation tools have the potential to improve reproducibility, reduce waste in research and increase the success of translational studies.

Loss of amphiregulin reduces myoepithelial cell coverage of mammary ducts and alters breast tumor growth

BACKGROUND

Amphiregulin (AREG), a ligand of the epidermal growth factor receptor, is not only essential for proper mammary ductal development, but also associated with breast cancer proliferation and growth. In the absence of AREG, mammary ductal growth is stunted and fails to expand. Furthermore, suppression of AREG expression in estrogen receptor-positive breast tumor cells inhibits in-vitro and in-vivo growth.

METHODS

We crossed AREG-null (AREG-/-) mice with the murine luminal B breast cancer model, MMTV-PyMT (PyMT), to generate spontaneous breast tumors that lack AREG (AREG-/- PyMT). We evaluated tumor growth, cytokeratin-8 (K8)-positive luminal cells, cytokeratin-14 (K14)-positive myoepithelial cells, and expression of AREG, Ki67, and PyMT. Primary myoepithelial cells from nontumor-bearing AREG+/+ mice underwent fluorescence-activated cell sorting and were adapted to culture for in-vitro coculture studies with AT-3 cells, a cell line derived from C57Bl/6 PyMT mammary tumors.

RESULTS

Intriguingly, PyMT-induced lesions progress more rapidly in AREG-/- mice than in AREG+/+ mice. Quantification of K8+ luminal and K14+ myoepithelial cells in non-PyMT AREG-/- mammary glands showed fewer K14+ cells and a thinner myoepithelial layer. Study of AT-3 cells indicated that coculture with myoepithelial cells or exposure to AREG, epidermal growth factor, or basic fibroblast growth factor can suppress PyMT expression. Late-stage AREG-/- PyMT tumors are significantly less solid in structure, with more areas of papillary and cystic growth. Papillary areas appear to be both less proliferative and less necrotic. In The Cancer Genome Atlas database, luminal-B invasive papillary carcinomas have lower AREG expression than luminal B invasive ductal carcinomas.

CONCLUSIONS

Our study has revealed a previously unknown role of AREG in myoepithelial cell development and PyMT expression. AREG expression is essential for proper myoepithelial coverage of mammary ducts. Both AREG and myoepithelial cells can suppress PyMT expression. We find that lower AREG expression is associated with invasive papillary breast cancer in both the MMTV-PyMT model and human breast cancer.

BHLHE40 confers a pro-survival and pro-metastatic phenotype to breast cancer cells by modulating HBEGF secretion

Background

Metastasis is responsible for a significant number of breast cancer-related deaths. Hypoxia, a primary driving force of cancer metastasis, induces the expression of BHLHE40, a transcription regulator. This study aimed to elucidate the function of BHLHE40 in the metastatic process of breast cancer cells.

Methods

To define the role of BHLHE40 in breast cancer, BHLHE40 expression was knocked down by a lentiviral construct expressing a short hairpin RNA against BHLHE40 or knocked out by the CRISPR/Cas9 editing system. Orthotopic xenograft and experimental metastasis (tail vein injection) mouse models were used to analyze the role of BHLHE40 in lung metastasis of breast cancer. Global gene expression analysis and public database mining were performed to identify signaling pathways regulated by BHLHE40 in breast cancer. The action mechanism of BHLHE40 was examined by chromatin immunoprecipitation (ChIP), co-immunoprecipitation (CoIP), exosome analysis, and cell-based assays for metastatic potential.

Results

BHLHE40 knockdown significantly reduced primary tumor growth and lung metastasis in orthotopic xenograft and experimental metastasis models of breast cancer. Gene expression analysis implicated a role of BHLHE40 in transcriptional activation of heparin-binding epidermal growth factor (HBEGF). ChIP and CoIP assays revealed that BHLHE40 induces HBEGF transcription by blocking DNA binding of histone deacetylases (HDAC)1 and HDAC2. Cell-based assays showed that HBEGF is secreted through exosomes and acts to promote cell survival and migration. Public databases provided evidence linking high expression of BHLHE40 and HBEGF to poor prognosis of triple-negative breast cancer.

Conclusion

This study reveals a novel role of BHLHE40 in promoting tumor cell survival and migration by regulating HBEGF secretion.

A proteomic analysis of chemoresistance development via sequential treatment with doxorubicin reveals novel players in MCF‑7 breast cancer cells

Breast cancer exhibits the highest incidence of all cancer types and is the 2nd leading cause of cancer mortality in women. Up to 82% of breast cancer patients receive a chemotherapy-containing treatment regimen. However, numerous breast tumors recur within 10 years following an initial response and are frequently resistant to previous therapeutic agents. Thus, to analyze the crucial factors, and whether the development of resistance in tumor cells follows certain patterns, is of great importance. In the present study, the clinical treatment schedule of the frequently used chemotherapeutic drug doxorubicin was applied in an in vitro model, the Molecular Evolution Assay (MEA), leading to resistance formation. By investigating the alterations in protein expression in MCF-7 breast cancer cells with three biological replicates, it was observed that the development of resistance to doxorubicin is a multi-directed process. The number and composition of the differentially expressed proteins varied, in addition to the pathways involved in chemoresistance, leading to only a small number of proteins and pathways being commonly regulated in all the MEAs. The proteins 60S ribosomal export protein NMD3 and 4F2 cell-surface antigen heavy chain (SLC3A2) were identified to be the most promising differentially expressed targets; the gene ontology term 'apoptotic signaling pathway' was reduced and 'cell redox homeostasis' was upregulated. Based on the present findings in vitro, it may be hypothesized that the development of resistance in patients is an even more complex process, emphasizing the need for further investigations of resistance development in the clinic to eventually improve patient outcomes.

Targeting invadopodia for blocking breast cancer metastasis

Dissemination of cancer cells from the primary tumor and their spread to distant sites of the body is the leading cause of mortality in metastatic cancer patients. Metastatic cancer cells invade surrounding tissues and blood vessels by forming F-actin-rich protrusions known as invadopodia, which degrade the extracellular matrix and enable invasion of tumor cells through it. Invadopodia have now been observed in vivo, and recent evidence demonstrates direct molecular links between assembly of invadopodia and cancer metastasis in both mouse models and in human patients. While significant progress has been achieved in the last decade in understanding the molecular mechanisms and signaling pathways regulating invadopodia formation and function, the application of this knowledge to development of prognostic and therapeutic approaches for cancer metastasis has not been discussed before. Here, we provide a detailed overview of current prognostic markers and tests for cancer metastasis and discuss their advantages, disadvantages, and their predicted efficiency. Using bioinformatic patient database analysis, we demonstrate, for the first time, a significant correlation between invadopodia-associated genes to breast cancer metastasis, suggesting that invadopodia could be used as both a prognostic marker and as a therapeutic target for blocking cancer metastasis. We include here a novel network interaction map of invadopodia-associated proteins with currently available inhibitors, demonstrating a central role for the recently identified EGFR-Pyk2-Src-Arg-cortactin invadopodial pathway, to which re-purposing of existent inhibitors could be used to block breast cancer metastasis. We then present an updated overview of current cancer-related clinical trials, demonstrating the negligible number of trials focusing on cancer metastasis. We also discuss the difficulties and complexity of performing cancer metastasis clinical trials, and the possible development of anti-metastasis drug resistance when using a prolonged preventive treatment with invadopodia inhibitors. This review presents a new perspective on invadopodia-mediated tumor invasiveness and may lead to the development of novel prognostic and therapeutic approaches for cancer metastasis.

Tumor suppressor miR-1 inhibits tumor growth and metastasis by simultaneously targeting multiple genes

Cancer progression depends on tumor growth and metastasis, which are activated or suppressed by multiple genes. An individual microRNA may target multiple genes, suggesting that a miRNA may suppress tumor growth and metastasis via simultaneously targeting different genes. However, thus far, this issue has not been explored. In the present study, the findings showed that miR-1 could simultaneously inhibit tumor growth and metastasis of gastric and breast cancers by targeting multiple genes. The results indicated that miR-1 was significantly downregulated in cancer tissues compared with normal tissues. The miR-1 overexpression led to cell cycle arrest in the G1 phase in gastric and breast cancer cells but not in normal cells. Furthermore, the miR-1 overexpression significantly inhibited the metastasis of gastric and breast cancer cells. An analysis of the underlying mechanism revealed that the simultaneous inhibition of tumor growth and metastasis mediated by miR-1 was due to the synchronous targeting of 6 miR-1 target genes encoding cyclin dependent kinase 4, twinfilin actin binding protein 1, calponin 3, coronin 1C, WAS protein family member 2 and thymosin beta 4, X-linked. In vivo assays demonstrated that miR-1 efficiently inhibited tumor growth and metastasis of gastric and breast cancers in nude mice. Therefore, our study contributed novel insights into the miR-1′s roles in tumorigenesis of gastric and breast cancers.

Comparative Proteomics of Dying and Surviving Cancer Cells Improves the Identification of Drug Targets and Sheds Light on Cell Life/Death Decisions

Chemotherapeutics cause the detachment and death of adherent cancer cells. When studying the proteome changes to determine the protein target and mechanism of action of anticancer drugs, the still-attached cells are normally used, whereas the detached cells are usually ignored. To test the hypothesis that proteomes of detached cells contain valuable information, we separately analyzed the proteomes of detached and attached HCT-116, A375, and RKO cells treated for 48 h with 5-fluorouracil, methotrexate and paclitaxel. Individually, the proteomic data on attached and detached cells had comparable performance in target and drug mechanism deconvolution, whereas the combined data significantly improved the target ranking for paclitaxel. Comparative analysis of attached versus detached proteomes provided further insight into cell life and death decision making. Six proteins consistently up- or downregulated in the detached versus attached cells regardless of the drug and cell type were discovered; their role in cell death/survival was tested by silencing them with siRNA. Knocking down USP11, CTTN, ACAA2, and EIF4H had anti-proliferative effects, affecting UHRF1 additionally sensitized the cells to the anticancer drugs, while knocking down RNF-40 increased cell survival against the treatments. Therefore, adding detached cells to the expression proteomics analysis of drug-treated cells can significantly increase the analytical value of the approach. The data have been deposited to the ProteomeXchange with identifier PXD007686.