Regulation of cancer stem cells in triple negative breast cancer

Inhibition of Cancer Stem-like Cells by Curcumin and Other Polyphenol Derivatives in MDA-MB-231 TNBC Cells

Triple-negative breast cancer (TNBC) accounts for 15% of all breast cancers and is highly aggressive. Despite an initial positive response to chemotherapy, most patients experience rapid disease progression leading to relapse and metastasis. This is attributed to the presence of breast cancer stem cells (BCSCs) within the tumor, which are characterized by self-renewal, pluripotency, and resistance mechanisms. Targeting BCSCs has become critical as conventional therapies fail to eradicate them due to a lack of specific targets. Curcumin, a polyphenol derived from turmeric (Curcuma longa), exhibits anticancer effects against breast cancer cells and BCSCs. The use of curcumin derivatives has been suggested as an approach to overcome the bioavailability and solubility problems of curcumin in humans, thereby increasing its anticancer effects. The aim of this study was to evaluate the cellular and molecular effects of six synthetic compounds derived from the natural polyphenol epigallocatechin gallate (EGCG) (TL1, TL2) and curcumin derivatives (TL3, TL4, TL5, and TL6) on a TNBC mesenchymal stem-like cell line. The activity of the compounds against BCSCs was also determined by a mammosphere inhibition assay and studying different BCSC markers by Western blotting. Finally, a drug combination assay was performed with the most promising compounds to evaluate their potential synergistic effects with the chemotherapeutic agents doxorubicin, cisplatin, and paclitaxel. The results showed that compounds exhibited specific cytotoxicity against the TNBC cell line and BCSCs. Interestingly, the combination of the curcumin derivative TL3 with doxorubicin and cisplatin displayed a synergistic effect in TNBC cells.

Identification and Pharmacological Targeting of Treatment-Resistant, Stem-like Breast Cancer Cells for Combination Therapy

Tumors frequently harbor isogenic yet epigenetically distinct subpopulations of multi-potent cells with high tumor-initiating potential-often called Cancer Stem-Like Cells (CSLCs). These can display preferential resistance to standard-of-care chemotherapy. Single-cell analyses can help elucidate Master Regulator (MR) proteins responsible for governing the transcriptional state of these cells, thus revealing complementary dependencies that may be leveraged via combination therapy. Interrogation of single-cell RNA sequencing profiles from seven metastatic breast cancer patients, using perturbational profiles of clinically relevant drugs, identified drugs predicted to invert the activity of MR proteins governing the transcriptional state of chemoresistant CSLCs, which were then validated by CROP-seq assays. The top drug, the anthelmintic albendazole, depleted this subpopulation in vivo without noticeable cytotoxicity. Moreover, sequential cycles of albendazole and paclitaxel-a commonly used chemotherapeutic -displayed significant synergy in a patient-derived xenograft (PDX) from a TNBC patient, suggesting that network-based approaches can help develop mechanism-based combinatorial therapies targeting complementary subpopulations.

Chemoresistance to additive PARP/PI3K dual inhibition in triple-negative breast cancer cell lines is associated with adaptive stem cell-like prevalence

Cancer stem-like cells (CSCs) are posited to exhibit specialized oncogenic capacity to drive malignancies. CSCs are distinguished by enhanced hallmarks of cancer, including apoptosis avoidance, phenotypic plasticity and aberrant growth pathway signaling. Standard-of-care chemotherapies targeted to rapidly cycling cells routinely fail to eliminate this resistant subpopulation, leading to disease recurrence and metastasis. Triple-negative breast cancer (TNBC), a highly aggressive subtype of breast cancer, is enriched for tumor-propagating CD44+/CD24-/low CSCs, which are poorly ablated by chemotherapeutics and are associated with poor prognosis. CD44 governs sustained PI3K signaling in breast cancer, which is essential for CSC maintenance. PI3K inhibition can elicit DNA damage and down-regulate BRCA1 expression, which in turn enhance the synthetic lethality of PARP inhibitors. Here, we examined a dual chemotherapeutic approach targeting these pathways by combining a pan-PI3K inhibitor (Buparlisib) and a PARP1 inhibitor (Olaparib) on a panel of TNBC cell lines with distinct mutational profiles and proportions of CSCs. We observed differential sensitivity to this dual inhibition strategy and varying cellular stress and resistance responses across eight TNBC lines. The dual chemotherapeutic effect is associated with a reduction in S-phase cells, an increased in apoptotic cells and elevated expression of cleaved PARP, indicating a provoked replicative stress response. We observed that PARP/PI3K inhibition efficacy was potentiated by repeated administration in some TNBC lines and identified critical treatment schedules, which further potentiated the dual chemotherapeutic effect. Dual inhibition induced small but significant increases in CSC relative abundance as marked by CD44+/CD24-/low or ALDH1+ cells and increased stress and survival signaling in multiple TNBC cell lines, suggesting this sub-population contributes to TNBC chemoresistance. These results suggest the additive effects of PARP and PI3K inhibition against CSC phenotypes may be enhanced by temporally-staged administration in TNBC cells.

The Potential of Stem Cells in Treating Breast Cancer

There has been a lot of interest in stem cell therapy as a means of curing disease in recent years. Despite extensive usage of stem cell therapy in the treatment of a wide range of medical diseases, it has been hypothesized that it plays a key part in the progression of cancer. Breast cancer is still the most frequent malignancy in women globally. However, the latest treatments, such as stem cell targeted therapy, are considered to be more effective in preventing recurrence, metastasis, and chemoresistance of breast cancer than older methods like chemotherapy and radiation. This review discusses the characteristics of stem cells and how stem cells may be used to treat breast cancer.

Targeting cancer stem cell plasticity in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype with limited treatment options. Cancer stem cells (CSCs) are thought to play a crucial role in TNBC progression and resistance to therapy. CSCs are a small subpopulation of cells within tumors that possess self-renewal and differentiation capabilities and are responsible for tumor initiation, maintenance, and metastasis. CSCs exhibit plasticity, allowing them to switch between states and adapt to changing microenvironments. Targeting CSC plasticity has emerged as a promising strategy for TNBC treatment. This review summarizes recent advances in understanding the molecular mechanisms underlying CSC plasticity in TNBC and discusses potential therapeutic approaches targeting CSC plasticity.

Breast cancer stem cells generate immune-suppressive T regulatory cells by secreting TGFβ to evade immune-elimination

Cancer stem cells (CSCs), being the primary contributors in tumor initiation, metastasis, and relapse, ought to have seminal roles in evasion of immune surveillance. Tumor-promoting CD4+CD25+FOXP3+ T-regulatory cells (Tregs) have been described to abolish host defense mechanisms by impeding the activities of other immune cells including effector T cells. However, whether CSCs can convert effector T cells to immune-suppressive Treg subset, and if yes, the mechanism underlying CSC-induced Treg generation, are limitedly studied. In this regard, we observed a positive correlation between breast CSC and Treg signature markers in both in-silico and immunohistochemical analyses. Mirroring the conditions during tumor initiation, low number of CSCs could successfully generate CD4+CD25+FOXP3+ Treg cells from infiltrating CD4+ T lymphocytes in a contact-independent manner. Suppressing the proliferation potential as well as IFNγ production capacity of effector T cells, these Treg cells might be inhibiting antitumor immunity, thereby hindering immune-elimination of CSCs during tumor initiation. Furthermore, unlike non-stem cancer cells (NSCCs), CSCs escaped doxorubicin-induced apoptosis, thus constituting major surviving population after three rounds of chemotherapy. These drug-survived CSCs were also able to generate CD4+CD25+FOXP3+ Treg cells. Our search for the underlying mechanism further unveiled the role of CSC-shed immune-suppressive cytokine TGFβ, which was further increased by chemotherapy, in generating tumor Treg cells. In conclusion, during initiation as well as after chemotherapy, when NSCCs are not present in the tumor microenvironment, CSCs, albeit present in low numbers, generate immunosuppressive CD4+CD25+FOXP3+ Treg cells in a contact-independent manner by shedding high levels of immune-suppressive Treg-polarizing cytokine TGFβ, thus escaping immune-elimination and initiating the tumor or causing tumor relapse.

Downregulation of complement factor H attenuates the stemness of MDA‑MB‑231 breast cancer cells via modulation of the ERK and p38 signaling pathways

The complement system is a powerful innate immune system deployed in the immediate response to pathogens and cancer cells. Complement factor H (CFH), one of the regulators involved in the complement cascade, can interrupt the death of target cells. Certain types of cancer, such as breast cancer, can adopt an aggressive phenotype, such as breast cancer stem cells (BCSCs), through enhancement of the defense system against complement attack by amplifying various complement regulators. However, little is known about the association between CFH and BCSCs. In the present study, the roles of CFH in the CSC characteristics and radioresistance of MDA-MB-231 human breast cancer cells were investigated. CFH knockdown in MDA-MB-231 cells decreased the viability of the cells upon complement cascade activation. Notably, CFH knockdown also decreased cell survival and suppressed mammosphere formation, cell migration and cell invasion by attenuating radioresistance. Additionally, CFH knockdown further enhanced irradiation-induced apoptosis through G2/M cell cycle arrest. It was also discovered that CFH knockdown attenuated the aggressive phenotypes of cancer cells by regulating CSC-associated gene expression. Finally, by microarray analysis, it was found that the expression of erythrocyte membrane protein band 4.1-like 3 (EPB41L3) was markedly increased following CFH knockdown. EPB41L3 inhibited ERK and activated the p38 MAPK signaling pathway. Taken together, these results indicated that CFH knockdown attenuated CSC properties and radioresistance in human breast cancer cells via controlling MAPK signaling and through upregulation of the tumor suppressor, EPB41L3.

Downregulation of TAB182 promotes cancer stem-like cell properties and therapeutic resistance in triple-negative breast cancer cells

TAB182 participates in DNA damage repair and radio-/chemosensitivity regulation in various tumors, but its role in tumorigenesis and therapeutic resistance in breast cancer remains unclear. In the current paper, we observed that triple-negative Breast Cancer (TNBC), a highly aggressive type of breast cancer, exhibits a lower expression of TAB182. TAB182 knockdown stimulates the proliferation, migration, and invasion of TNBC cells. Our study first obtained RNA-seq data to explore the cellular functions mediated by TAB182 at the genome level in TNBC cells. A transcriptome analysis and in vitro experiments enabled us to identify that TAB182 downregulation drives the enhanced properties of cancer stem-like cells (CSCs) in TNBC cells. Furthermore, TAB182 deletion contributes to the resistance of cells to olaparib or cisplatin, which can be rescued by silencing GLI2, a gene downstream of cancer stemness-related signaling pathways. Our results reveal a novel function of TAB182 as a potential negative regulator of cancer stem-like properties and drug sensitivity in TNBC cells, suggesting that TAB182 may be a tumor suppressor gene and is associated with increased therapeutic benefits for TNBC patients.

Phenotypic heterogeneity drives differential disease outcome in a mouse model of triple negative breast cancer

The triple negative breast cancer (TNBC) subtype is one of the most aggressive forms of breast cancer that has poor clinical outcome and is an unmet clinical challenge. Accumulating evidence suggests that intratumoral heterogeneity or the presence of phenotypically distinct cell populations within a tumor play a crucial role in chemoresistance, tumor progression and metastasis. An increased understanding of the molecular regulators of intratumoral heterogeneity is crucial to the development of effective therapeutic strategies in TNBC. To this end, we used an unbiased approach to identify a molecular mediator of intratumoral heterogeneity in breast cancer by isolating two tumor cell populations (T1 and T2) from the 4T1 TNBC model. Phenotypic characterization revealed that the cells are different in terms of their morphology, proliferation and self-renewal ability in vitro as well as primary tumor formation and metastatic potential in vivo. Bioinformatic analysis followed by Kaplan Meier survival analysis in TNBC patients identified Metastasis associated colon cancer 1 (Macc1) as one of the top candidate genes mediating the aggressive phenotype in the T1 tumor cells. The role of Macc1 in regulating the proliferative phenotype was validated and taken forward in a therapeutic context with Lovastatin, a small molecule transcriptional inhibitor of Macc1 to target the T1 cell population. This study increases our understanding of the molecular underpinnings of intratumoral heterogeneity in breast cancer that is critical to improve the treatment of women currently living with the highly aggressive TNBC subtype.

RNF40 epigenetically modulates glycolysis to support the aggressiveness of basal-like breast cancer

Triple-negative breast cancer (TNBC) is the most difficult breast cancer subtype to treat due to the lack of targeted therapies. Cancer stem cells (CSCs) are strongly enriched in TNBC lesions and are responsible for the rapid development of chemotherapy resistance and metastasis. Ubiquitin-based epigenetic circuits are heavily exploited by CSCs to regulate gene transcription and ultimately sustain their aggressive behavior. Therefore, therapeutic targeting of these ubiquitin-driven dependencies may reprogram the transcription of CSC and render them more sensitive to standard therapies. In this work, we identified the Ring Finger Protein 40 (RNF40) monoubiquitinating histone 2B at lysine 120 (H2Bub1) as an indispensable E3 ligase for sustaining the stem-cell-like features of the growing mammary gland. In addition, we found that the RNF40/H2Bub1-axis promotes the CSC properties and drug-tolerant state by supporting the glycolytic program and promoting pro-tumorigenic YAP1-signaling in TNBC. Collectively, this study unveils a novel tumor-supportive role of RNF40 and underpins its high therapeutic value to combat the malignant behavior of TNBC.

Engineered vitamin E-tethered non-immunogenic facial lipopeptide for developing improved siRNA based combination therapy against metastatic breast cancer

RNA interference based therapeutic gene silencing is an emerging platform for managing highly metastatic breast cancer. Cytosolic delivery of functional siRNA remains the key obstacle for efficient RNAi therapy. To overcome the challenges of siRNA delivery, we have engineered a vitamin E-tethered, short, optimum protease stabilized facial lipopeptide based non-immunogenic, biocompatible siRNA transporter to facilitate the clinical translation in future. Our designed lipopeptide has an Arginine-Sarcosine-Arginine segment for providing optimum protease-stability, minimizing adjacent arginine-arginine repulsion and reducing intermolecular aggregation and α-tocopherol as the lipidic moiety for facilitating cellular permeabilization. Interestingly, our designed non-immunogenic siRNA transporter has exhibited significantly better long term transfection efficiency than HiPerFect and can transfect hard to transfect primary cell line, HUVEC. Our engineered siRNA therapeutics demonstrated high efficacy in managing metastasis against triple negative breast cancer by disrupting the crosstalk of endothelial cells and MDA-MB-231 and reduced stemness and metastatic markers, as evidenced by downregulating critical oncogenic pathways. Our study aimed at silencing Notch1 signalling to achieve "multi-targeted" therapy with a single putative molecular medicine. We have further developed mechanistically rational combination therapy combining Notch1 silencing with a repurposed drug m-TOR inhibitor, metformin, which demonstrated synergistic interaction and enhanced antitumor efficacy against cancer metastasis.

Hypoxia: syndicating triple negative breast cancer against various therapeutic regimens

Triple-negative breast cancer (TNBC) is one of the deadliest subtypes of breast cancer (BC) for its high aggressiveness, heterogeneity, and hypoxic nature. Based on biological and clinical observations the TNBC related mortality is very high worldwide. Emerging studies have clearly demonstrated that hypoxia regulates the critical metabolic, developmental, and survival pathways in TNBC, which include glycolysis and angiogenesis. Alterations to these pathways accelerate the cancer stem cells (CSCs) enrichment and immune escape, which further lead to tumor invasion, migration, and metastasis. Beside this, hypoxia also manipulates the epigenetic plasticity and DNA damage response (DDR) to syndicate TNBC survival and its progression. Hypoxia fundamentally creates the low oxygen condition responsible for the alteration in Hypoxia-Inducible Factor-1alpha (HIF-1α) signaling within the tumor microenvironment, allowing tumors to survive and making them resistant to various therapies. Therefore, there is an urgent need for society to establish target-based therapies that overcome the resistance and limitations of the current treatment plan for TNBC. In this review article, we have thoroughly discussed the plausible significance of HIF-1α as a target in various therapeutic regimens such as chemotherapy, radiotherapy, immunotherapy, anti-angiogenic therapy, adjuvant therapy photodynamic therapy, adoptive cell therapy, combination therapies, antibody drug conjugates and cancer vaccines. Further, we also reviewed here the intrinsic mechanism and existing issues in targeting HIF-1α while improvising the current therapeutic strategies. This review highlights and discusses the future perspectives and the major alternatives to overcome TNBC resistance by targeting hypoxia-induced signaling.

Management of hyperglycaemia in type 2 diabetes, 2022. A consensus report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD)

The American Diabetes Association and the European Association for the Study of Diabetes convened a panel to update the previous consensus statements on the management of hyperglycaemia in type 2 diabetes in adults, published since 2006 and last updated in 2019. The target audience is the full spectrum of the professional healthcare team providing diabetes care in the USA and Europe. A systematic examination of publications since 2018 informed new recommendations. These include additional focus on social determinants of health, the healthcare system and physical activity behaviours including sleep. There is a greater emphasis on weight management as part of the holistic approach to diabetes management. The results of cardiovascular and kidney outcomes trials involving sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide-1 receptor agonists, including assessment of subgroups, inform broader recommendations for cardiorenal protection in people with diabetes at high risk of cardiorenal disease. After a summary listing of consensus recommendations, practical tips for implementation are provided.

Glucose Enhances Pro-Tumorigenic Functions of Mammary Adipose-Derived Mesenchymal Stromal/Stem Cells on Breast Cancer Cell Lines

Adiposity and diabetes affect breast cancer (BC) progression. We addressed whether glucose may affect the interaction between mammary adipose tissue-derived mesenchymal stromal/stem cells (MAT-MSCs) and BC cells. Two-dimensional co-cultures and spheroids were established in 25 mM or 5.5 mM glucose (High Glucose-HG or Low Glucose-LG) by using MAT-MSCs and MCF7 or MDA-MB231 BC cells. Gene expression was measured by qPCR, while protein levels were measured by cytofluorimetry and ELISA. CD44high/CD24low BC stem-like sub-population was quantified by cytofluorimetry. An in vivo zebrafish model was assessed by injecting spheroid-derived labeled cells. MAT-MSCs co-cultured with BC cells showed an inflammatory/senescent phenotype with increased abundance of IL-6, IL-8, VEGF and p16INK4a, accompanied by altered levels of CDKN2A and LMNB1. BC cells reduced multipotency and increased fibrotic features modulating OCT4, SOX2, NANOG, αSMA and FAP in MAT-MSCs. Of note, these co-culture-mediated changes in MAT-MSCs were partially reverted in LG. Only in HG, MAT-MSCs increased CD44high/CD24low MCF7 sub-population and promoted their ability to form mammospheres. Injection in zebrafish embryos of HG spheroid-derived MCF7 and MAT-MSCs was followed by a significant cellular migration and caudal dissemination. Thus, MAT-MSCs enhance the aggressiveness of BC cells in a HG environment.

Tumor Necrosis Factor-α (TNFα) Stimulate Triple-Negative Breast Cancer Stem Cells to Promote Intratumoral Invasion and Neovasculogenesis in the Liver of a Xenograft Model

TNBC represents the most aggressive breast cancer subtype. Although cancer stem cells (CSCs) are a minor fraction of all cancer cells, they are highly cancerous when compared to their non-stem counterparts, playing a major role in tumor recurrence and metastasis. Angiogenic stimuli and the tumor environment response are vital factors in cancer metastasis. However, the causes and effects of tumor angiogenesis are still poorly understood. In this study, we demonstrate TNFα effects on primary triple-negative breast cancer stem cells (BCSCs). TNFα stimulation increased the mesenchymality of BCSCs in an intermediate epithelial-to-mesenchymal transition (EMT) state, enhanced proliferation, self-renewal, and invasive capacity. TNFα-treatment elicited BCSC signaling on endothelial networks in vitro and increased the network forming capacity of the endothelial cells. Our findings further demonstrate that TNFα stimulation in BCSCs has the ability to instigate distinct cellular communication within the tumor microenvironment, inducing intra-tumoral stromal invasion. Further, TNFα-treatment in BCSCs induced a pre-metastatic niche through breast-liver organ crosstalk by inducing vascular cell adhesion molecule-1 (VCAM-1) enriched neovasculogenesis in the liver of tumor-bearing mice. Overall, TNFα is an important angiogenic target to be considered in breast cancer progression to attenuate any angiogenic response in the tumor environment that could lead to secondary organ metastasis.

The TH1902 Docetaxel Peptide-Drug Conjugate Inhibits Xenografts Growth of Human SORT1-Positive Ovarian and Triple-Negative Breast Cancer Stem-like Cells

Background: Breast and ovarian cancer stem cells (CSC) can contribute to the invasive and chemoresistance phenotype of tumors. TH1902, a newly developed sortilin (SORT1)-targeted peptide-docetaxel conjugate is currently in phase-1 clinical trial. Whether TH1902 impacts the chemoresistance phenotype of human triple-negative breast CSC (hTNBCSC) and ovarian CSC (hOvCSC) is unknown. Methods and Results: Immunophenotyping of hTNBCSC and hOvCSC was performed by flow cytometry and confirmed the expression of SORT1, and of CSC markers CD133, NANOG, and SOX2. Western blotting demonstrated the expression of the drug efflux pumps from the P-gp family members, ABCB1 and ABCB5. The cellular uptake of the fluorescent Alexa⁴⁸⁸-peptide from TH1902 was inhibited upon siRNA-mediated repression of SORT1 or upon competition with SORT1 ligands. In contrast to docetaxel, TH1902 inhibited in vitro migration, induced cell apoptosis and lead to G2/M cell cycle arrest of the hTNBCSC. These events were unaffected by the presence of the P-gp inhibitors cyclosporine A or PSC-833. In vivo, using immunosuppressed nude mice xenografts, TH1902 significantly inhibited the growth of hTNBCSC and hOvCSC xenografts (~80% vs. ~35% for docetaxel) when administered weekly as intravenous bolus for three cycles at 15 mg/kg, a dose equivalent to the maximal tolerated dose of docetaxel. Therapeutic efficacy was further observed when carboplatin was combined to TH1902. Conclusions: Overall, TH1902 exerts a superior anticancer activity than the unconjugated docetaxel, in part, by circumventing the CSC drug resistance phenotype that could potentially reduce cancer recurrence attributable to CSC.

Phenanthroindolizidine Alkaloids Isolated from Tylophora ovata as Potent Inhibitors of Inflammation, Spheroid Growth, and Invasion of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC), representing the most aggressive form of breast cancer with currently no targeted therapy available, is characterized by an inflammatory and hypoxic tumor microenvironment. To date, a broad spectrum of anti-tumor activities has been reported for phenanthroindolizidine alkaloids (PAs), however, their mode of action in TNBC remains elusive. Thus, we investigated six naturally occurring PAs extracted from the plant Tylophora ovata: O-methyltylophorinidine (1) and its five derivatives tylophorinidine (2), tylophoridicine E (3), 2-demethoxytylophorine (4), tylophoridicine D (5), and anhydrodehydrotylophorinidine (6). In comparison to natural (1) and for more-in depth studies, we also utilized a sample of synthetic O-methyltylophorinidine (1s). Our results indicate a remarkably effective blockade of nuclear factor kappa B (NFκB) within 2 h for compounds (1) and (1s) (IC50 = 17.1 ± 2.0 nM and 3.3 ± 0.2 nM) that is different from its effect on cell viability within 24 h (IC50 = 13.6 ± 0.4 nM and 4.2 ± 1 nM). Furthermore, NFκB inhibition data for the additional five analogues indicate a structure–activity relationship (SAR). Mechanistically, NFκB is significantly blocked through the stabilization of its inhibitor protein kappa B alpha (IκBα) under normoxic as well as hypoxic conditions. To better mimic the TNBC microenvironment in vitro, we established a 3D co-culture by combining the human TNBC cell line MDA-MB-231 with primary murine cancer-associated fibroblasts (CAF) and type I collagen. Compound (1) demonstrates superiority against the therapeutic gold standard paclitaxel by diminishing spheroid growth by 40% at 100 nM. The anti-proliferative effect of (1s) is distinct from paclitaxel in that it arrests the cell cycle at the G0/G1 state, thereby mediating a time-dependent delay in cell cycle progression. Furthermore, (1s) inhibited invasion of TNBC monoculture spheroids into a matrigel®-based environment at 10 nM. In conclusion, PAs serve as promising agents with presumably multiple target sites to combat inflammatory and hypoxia-driven cancer, such as TNBC, with a different mode of action than the currently applied chemotherapeutic drugs.

Oncogenic and Stemness Signatures of the High-Risk HCMV Strains in Breast Cancer Progression

Simple Summary

Lately, human cytomegalovirus (HCMV) has been progressively implicated in carcinogenesis alongside its oncomodulatory impact. CMV-Transformed Human mammary epithelial cells (CTH) phenotype might be defined by giant cell cycling, whereby the generation of polyploid giant cancer cells (PGCCs) could expedite the acquisition of malignant phenotypes. Herein, the main study objectives were to assess the transformation potential in vitro and evaluate the obtained cellular phenotype, the genetic and molecular features, and the activation of cellular stemness programs of HCMV strains, B544 and B693, which were previously isolated from triple-negative breast cancer (TNBC) biopsies. The strains’ sensitivity to paclitaxel and ganciclovir combination therapy was evaluated. A unique molecular landscape was unveiled in the tumor microenvironment of TNBC harboring high-risk HCMV. Overall, the explicit oncogenic and stemness signatures highlight HCMV potential in breast cancer progression thus paving the way for targeted therapies and clinical interventions which prolong the overall survival of breast cancer patients.

Abstract

Background: Human cytomegalovirus (HCMV) oncomodulation, molecular mechanisms, and ability to support polyploid giant cancer cells (PGCCs) generation might underscore its contribution to oncogenesis, especially breast cancers. The heterogeneity of strains can be linked to distinct properties influencing the virus-transforming potential, cancer types induced, and patient’s clinical outcomes. Methods: We evaluated the transforming potential in vitro and assessed the acquired cellular phenotype, genetic and molecular features, and stimulation of stemness of HCMV strains, B544 and B693, isolated from EZH2^HighMyc^High triple-negative breast cancer (TNBC) biopsies. Therapeutic response assessment after paclitaxel (PTX) and ganciclovir (GCV) treatment was conducted in addition to the molecular characterization of the tumor microenvironment (TME). Findings: HCMV-B544 and B693 transformed human mammary epithelial cells (HMECs). We detected multinucleated and lipid droplet-filled PGCCs harboring HCMV. Colony formation was detected and Myc was overexpressed in CMV-Transformed-HMECs (CTH cells). CTH-B544 and B693 stimulated stemness and established an epithelial/mesenchymal hybrid state. HCMV-IE1 was detected in CTH long-term cultures indicating a sustained viral replication. Biopsy B693 unveiled a tumor signature predicting a poor prognosis. CTH-B544 cells were shown to be more sensitive to PTX/GCV therapy. Conclusion: The oncogenic and stemness signatures of HCMV strains accentuate the oncogenic potential of HCMV in breast cancer progression thereby leading the way for targeted therapies and innovative clinical interventions that will improve the overall survival of breast cancer patients.

Countering Triple Negative Breast Cancer via Impeding Wnt/β-Catenin Signaling, a Phytotherapeutic Approach

Triple negative breast cancer (TNBC) is characterized as a heterogeneous disease with severe malignancy and high mortality. Aberrant Wnt/β-catenin signaling is responsible for self-renewal and mammosphere generation, metastasis and resistance to apoptosis and chemotherapy in TNBC. Nonetheless, in the absence of a targeted therapy, chemotherapy is regarded as the exclusive treatment strategy for the treatment of TNBC. This review aims to provide an unprecedented overview of the plants and herbal derivatives which repress the progression of TNBC through prohibiting the Wnt/β-catenin pathway. Herbal medicine extracts and bioactive compounds (alkaloids, retinoids. flavonoids, terpenes, carotenoids and lignans) alone, in combination with each other and/or with chemotherapy agents could interrupt the various steps of Wnt/β-catenin signaling, i.e., WNT, FZD, LRP, GSK3β, Dsh, APC, β-catenin and TCF/LEF. These phytotherapy agents diminish proliferation, metastasis, breast cancer stem cell self-renewal and induce apoptosis in cell and animal models of TNBC through the down-expression of the downstream target genes of Wnt signaling. Some of the herbal derivatives simultaneously impede Wnt/β-catenin signaling and other overactive pathways in triple negative breast cancer, including: mTORC1; ER stress and SATB1 signaling. The herbal remedies and their bioactive ingredients perform essential roles in the treatment of the very fatal TNBC via repression of Wnt/β-catenin signaling.

Addiction of Cancer Stem Cells to MUC1-C in Triple-Negative Breast Cancer Progression

Triple-negative breast cancer (TNBC) is an aggressive malignancy with limited treatment options. TNBC progression is associated with expansion of cancer stem cells (CSCs). Few insights are available regarding druggable targets that drive the TNBC CSC state. This review summarizes the literature on TNBC CSCs and the compelling evidence that they are addicted to the MUC1-C transmembrane protein. In normal epithelia, MUC1-C is activated by loss of homeostasis and induces reversible wound-healing responses of inflammation and repair. However, in settings of chronic inflammation, MUC1-C promotes carcinogenesis. MUC1-C induces EMT, epigenetic reprogramming and chromatin remodeling in TNBC CSCs, which are dependent on MUC1-C for self-renewal and tumorigenicity. MUC1-C-induced lineage plasticity in TNBC CSCs confers DNA damage resistance and immune evasion by chronic activation of inflammatory pathways and global changes in chromatin architecture. Of therapeutic significance, an antibody generated against the MUC1-C extracellular domain has been advanced in a clinical trial of anti-MUC1-C CAR T cells and in IND-enabling studies for development as an antibody–drug conjugate (ADC). Agents targeting the MUC1-C cytoplasmic domain have also entered the clinic and are undergoing further development as candidates for advancing TNBC treatment. Eliminating TNBC CSCs will be necessary for curing this recalcitrant cancer and MUC1-C represents a promising druggable target for achieving that goal.

Emergence of Nanotechnology as a Powerful Cavalry against Triple-Negative Breast Cancer (TNBC)

Triple-negative breast cancer (TNBC) is considered one of the un-manageable types of breast cancer, involving devoid of estrogen, progesterone, and human epidermal growth factor receptor 2 (HER 2) receptors. Due to their ability of recurrence and metastasis, the management of TNBC remains a mainstay challenge, despite the advancements in cancer therapies. Conventional chemotherapy remains the only treatment regimen against TNBC and suffers several limitations such as low bioavailability, systemic toxicity, less targetability, and multi-drug resistance. Although various targeted therapies have been introduced to manage the hardship of TNBC, they still experience certain limitations associated with the survival benefits. The current research thus aimed at developing and improving the strategies for effective therapy against TNBC. Such strategies involved the emergence of nanoparticles. Nanoparticles are designated as nanocavalries, loaded with various agents (drugs, genes, etc.) to battle the progression and metastasis of TNBC along with overcoming the limitations experienced by conventional chemotherapy and targeted therapy. This article documents the treatment regimens of TNBC along with their efficacy towards different subtypes of TNBC, and the various nanotechnologies employed to increase the therapeutic outcome of FDA-approved drug regimens.

Diagnostic and prognostic value of miR-200 family in breast cancer: A meta-analysis and systematic review

BACKGROUND

Breast cancer (BC) is the most common cancer for women all over the world. Great interests have been paid to discover accurate and noninvasive methods for breast cancer diagnosis and prognosis. Although the diagnostic and prognostic value of microRNA-200 (miRNA- 200, miR-200) family has been revealed in many studies, the results were inconsistent. Thus, this meta-analysis aims to assess the overall value of miRNA-200 family in breast cancer diagnosis and prognosis.

METHOD

Relevant studies were searched from the following databases: PubMed, PMC, EMBASE, and ScienceDirect using key words: ("miRNA-200 family" or "miR-141" or "miR-200a" or "miR-200b" or "miR-200c" or "miR-429") and ("HER2" or "Luminal A" or "Luminal B" or "TNBC") and ("breast cancers" or "breast carcinoma" or "breast malignancy" or "breast tumor"). The sensitivity, specificity, AUC were then calculated to estimate the diagnostic accuracy of the miR-200 family. As for the prognostic value of the miR-200 family, the pooled hazard ratio (HR) was assessed. Heterogeneity among individual studies was also examined by subgroup analyses.

RESULT

A total of 24 articles were included in the meta-analysis. The diagnostic value of miR-200s in BC was presented by the pooled sensitivity was 0.86 (95% CI: 0.83-0.88); the pooled specificity was 0.82 (95% CI: 0.72-0.89); the pooled AUC was 0.931 (95% CI: 0.919-0.942). Besides, expression of miR-200s in metastatic breast cancer has sensitivity, specificity and AUC of 0.70 (95%CI: 0.56-0.81), 0.72 (95%CI: 0.61-0.81), and 0.814 (95%CI: 0.741-0.903), respectively. The meta-analysis then revealed that high expression of miR-200 family corresponded to poor OS (HR: 1.63, 95% CI: 1.03-2.52), poor DFS (HR: 1.55, 95% CI: 0.95-2.56) in BC patients while downregulation of miRNA-200s corresponded to poor OS (HR= 0.84, 95%CI: 0.46-1.63) in TNBC patients and poor OS (HR=0.49; 95%CI: 0.27-0.88) in luminal BC patient.

CONCLUSION

The MiR-200 family has high diagnostic accuracy and can be used as an important biomarker to prognosticate breast cancer.

Breast Cancer Stem Cell Membrane Biomarkers: Therapy Targeting and Clinical Implications

Breast cancer is the most common malignancy affecting women worldwide. Importantly, there have been significant improvements in prevention, early diagnosis, and treatment options, which resulted in a significant decrease in breast cancer mortality rates. Nevertheless, the high rates of incidence combined with therapy resistance result in cancer relapse and metastasis, which still contributes to unacceptably high mortality of breast cancer patients. In this context, a small subpopulation of highly tumourigenic cancer cells within the tumour bulk, commonly designated as breast cancer stem cells (BCSCs), have been suggested as key elements in therapy resistance, which are responsible for breast cancer relapses and distant metastasis. Thus, improvements in BCSC-targeting therapies are crucial to tackling the metastatic progression and might allow therapy resistance to be overcome. However, the design of effective and specific BCSC-targeting therapies has been challenging since there is a lack of specific biomarkers for BCSCs, and the most common clinical approaches are designed for commonly altered BCSCs signalling pathways. Therefore, the search for a new class of BCSC biomarkers, such as the expression of membrane proteins with cancer stem cell potential, is an area of clinical relevance, once membrane proteins are accessible on the cell surface and easily recognized by specific antibodies. Here, we discuss the significance of BCSC membrane biomarkers as potential prognostic and therapeutic targets, reviewing the CSC-targeting therapies under clinical trials for breast cancer.

The miR-200 Family of microRNAs: Fine Tuners of Epithelial-Mesenchymal Transition and Circulating Cancer Biomarkers

The miR-200 family of microRNAs (miRNAs) includes miR-200a, miR-200b, miR-200c, miR-141 and miR-429, five evolutionarily conserved miRNAs that are encoded in two clusters of hairpin precursors located on human chromosome 1 (miR-200b, miR-200a and miR-429) and chromosome 12 (miR-200c and miR-141). The mature -3p products of the precursors are abundantly expressed in epithelial cells, where they contribute to maintaining the epithelial phenotype by repressing expression of factors that favor the process of epithelial-to-mesenchymal transition (EMT), a key hallmark of oncogenic transformation. Extensive studies of the expression and interactions of these miRNAs with cell signaling pathways indicate that they can exert both tumor suppressor- and pro-metastatic functions, and may serve as biomarkers of epithelial cancers. This review provides a summary of the role of miR-200 family members in EMT, factors that regulate their expression, and important targets for miR-200-mediated repression that are involved in EMT. The second part of the review discusses the potential utility of circulating miR-200 family members as diagnostic/prognostic biomarkers for breast, colorectal, lung, ovarian, prostate and bladder cancers.