Triple-negative breast cancer and basal-like subtype : Pathology and targeted therapy

N6-Methyladenosine methylation modification in breast cancer: current insights

Breast cancer is the most common cancer type among women. Despite advanced treatment strategies, some patients still face challenges in disease control, prompting the exploration of new therapeutic approaches. N6-Methyladenosine (m6A) methylation modification regulates RNA and plays a crucial role in various tumor biological processes, closely linked to breast cancer occurrence, development, prognosis, and treatment. M6A regulators impact breast cancer progression, development, and drug resistance by modulating RNA metabolism and tumor-related pathways. Researchers have begun to understand the regulatory mechanisms of m6A methylation in breast cancer. This paper discusses the roles of m6A regulators in breast cancer progression, prognosis, and treatment, offering new perspectives for breast cancer diagnosis and treatment.

Kuwanon C inhibits proliferation and induction of apoptosis via the intrinsic pathway in MDA-MB231 and T47D breast cancer cells

Breast cancer ranks as the most prevalent malignancy, presenting persistent therapeutic challenges encompassing issues such as drug resistance, recurrent occurrences, and metastatic progression. Therefore, there is a need for targeted drugs that are less toxic and more effective against breast cancer. Kuwanon C, an isoamylated flavonoid derived from mulberry resources, has shown promise as a potential candidate due to its strong cytotoxicity against cancer cells. The present study focused on investigating the anticancer activity of kuwanon C in two human breast cancer cell lines, MDA-MB231 and T47D cells. MTS assay results indicated a decrease in cell proliferation with increasing concentrations of kuwanon C. Furthermore, kuwanon C upregulated the expression levels of the cyclin-dependent kinase inhibitor p21 and effectively inhibited cell DNA replication and induced DNA damage. Flow cytometry confirmed that kuwanon C induced cell apoptosis and upregulated the expression levels of pro-apoptotic proteins (Bax and c-caspase3). Additionally, it stimulated the production of reactive oxygen species (ROS) in the cells. Transmission electron microscopy and Fluo-4 AM-calcium ion staining experiments provided insights into the endoplasmic reticulum (ER), revealing that kuwanon C induced ER stress. Kuwanon C upregulated the expression levels of unfolded protein response-related proteins (ATF4, GADD34, HSPA5, and DDIT3). Overall, the present findings suggested that kuwanon C exerts a potent inhibitory effect on breast cancer cell proliferation through modulating of the p21, induction of mitochondrial-mediated apoptosis, activation of ER stress and induction of DNA damage. These results position kuwanon C as a potential targeted therapeutic agent for breast cancer.

Expression and function of cytokine interleukin-22 gene in the tumor microenvironment of triple negative breast cancer

BACKGROUND

The tumor microenvironment (TME) and interleukin-22 (IL-22) in cytokines have recently attracted much attention due to their potential impact on tumor biology. However, the role of IL-22 in triple negative breast cancer (TNBC) TME is still poorly understood. This article investigated the gene expression and function of IL-22 in TNBC TME.

METHODS

Tumor samples from TNBC patients were collected, and adjacent noncancerous tissues were used as controls. A functional test was performed to evaluate the impact of IL-22 for TNBC cells, including proliferation, migration, and apoptosis.

RESULTS

IL-22 gene expression in TNBC tumor samples was markedly higher relative to adjacent non-cancerous tissues (P < 0.05). In addition, it was also observed that IL-22facilitated proliferation and migration of TNBC cells, and inhibit apoptosis. This article reveals the role of IL-22 in the TME of TNBC. The up-regulation of IL-22 gene expression in TNBC tumors and its promoting effect on cancer cell invasiveness highlight its potential as a therapeutic target in TNBC treatment strategies.

CONCLUSION

The findings suggested that targeting IL-22 and its related pathways can offer new insights for developing effective therapies for TNBC.

[18F]F-Poly(ADP-Ribose) Polymerase Inhibitor Radiotracers for Imaging PARP Expression and Their Potential Clinical Applications in Oncology

Including poly(ADP-ribose) polymerase (PARP) inhibitors in managing patients with inoperable tumors has significantly improved outcomes. The PARP inhibitors hamper single-strand deoxyribonucleic acid (DNA) repair by trapping poly(ADP-ribose)polymerase (PARP) at sites of DNA damage, forming a non-functional "PARP enzyme-inhibitor complex" leading to cell cytotoxicity. The effect is more pronounced in the presence of PARP upregulation and homologous recombination (HR) deficiencies such as breast cancer-associated gene (BRCA1/2). Hence, identifying HR-deficiencies by genomic analysis-for instance, BRCA1/2 used in triple-negative breast cancer-should be a part of the selection process for PARP inhibitor therapy. Published data suggest BRCA1/2 germline mutations do not consistently predict favorable responses to PARP inhibitors, suggesting that other factors beyond tumor mutation status may be at play. A variety of factors, including tumor heterogeneity in PARP expression and intrinsic and/or acquired resistance to PARP inhibitors, may be contributing factors. This justifies the use of an additional tool for appropriate patient selection, which is noninvasive, and capable of assessing whole-body in vivo PARP expression and evaluating PARP inhibitor pharmacokinetics as complementary to the currently available BRCA1/2 analysis. In this review, we discuss [18F]Fluorine PARP inhibitor radiotracers and their potential in the imaging of PARP expression and PARP inhibitor pharmacokinetics. To provide context we also briefly discuss possible causes of PARP inhibitor resistance or ineffectiveness. The discussion focuses on TNBC, which is a tumor type where PARP inhibitors are used as part of the standard-of-care treatment strategy.

AMD1 promotes breast cancer aggressiveness via a spermidine-eIF5A hypusination-TCF4 axis

BACKGROUND

Basal-like breast cancer (BLBC) is the most aggressive subtype of breast cancer due to its aggressive characteristics and lack of effective therapeutics. However, the mechanism underlying its aggressiveness remains largely unclear. S-adenosylmethionine decarboxylase proenzyme (AMD1) overexpression occurs specifically in BLBC. Here, we explored the potential molecular mechanisms and functions of AMD1 promoting the aggressiveness of BLBC.

METHODS

The potential effects of AMD1 on breast cancer cells were tested by western blotting, colony formation, cell proliferation assay, migration and invasion assay. The spermidine level was determined by high performance liquid chromatography. The methylation status of CpG sites within the AMD1 promoter was evaluated by bisulfite sequencing PCR. We elucidated the relationship between AMD1 and Sox10 by ChIP assays and quantitative real-time PCR. The effect of AMD1 expression on breast cancer cells was evaluated by in vitro and in vivo tumorigenesis model.

RESULTS

In this study, we showed that AMD1 expression was remarkably elevated in BLBC. AMD1 copy number amplification, hypomethylation of AMD1 promoter and transcription activity of Sox10 contributed to the overexpression of AMD1 in BLBC. AMD1 overexpression enhanced spermidine production, which enhanced eIF5A hypusination, activating translation of TCF4 with multiple conserved Pro-Pro motifs. Our studies showed that AMD1-mediated metabolic system of polyamine in BLBC cells promoted tumor cell proliferation and tumor growth. Clinically, elevated expression of AMD1 was correlated with high grade, metastasis and poor survival, indicating poor prognosis of breast cancer patients.

CONCLUSION

Our work reveals the critical association of AMD1-mediated spermidine-eIF5A hypusination-TCF4 axis with BLBC aggressiveness, indicating potential prognostic indicators and therapeutic targets for BLBC.

Triple-negative breast cancer: from classical clinicopathological features to androgen receptor profile

Triple-negative breast cancer (BC) represents an extensively analyzed entity to establish the overall framework of clinicopathological characteristics, with an impact on defining prognostic and predictive factors. The relationship between triple-negative BC and androgen receptor (AR) is far from being clarified. We aimed to evaluate the classical clinicopathological spectrum that characterized a triple-negative BC, focusing on AR expression. The study group comprised 124 cases of triple-negative BC. The main clinicopathological parameters were extracted from medical records. The immunohistochemical (IHC) exam was run using the following antibodies: anti-estrogen receptor (ER), anti-progesterone receptor (PR), anti-human epidermal growth factor receptor (HER2∕neu), anti-Ki67 and anti-AR. AR immunoexpression was assessed as absent (completely negative) or present (unrelated to percentages and intensity). Data were statistically analyzed. AR expression was positive in 78 (63%) cases and negative in 46 (37%) cases. Among the study group, 28 cases exhibited an AR percentage ranging from 1% to 10%, 15 cases showed a percentage between 11% and 50%, while 12 cases had AR values between 51% and 75% and 23 cases fell within the AR range of 76% to 100%. No significant differences between AR immunoexpression (negative versus positive), clinicopathological characteristics and survival parameters were found. Statistically significant differences were registered between histological type, tumor stage, distant metastasis, tumor-infiltrating lymphocytes (TILs), treatment and residual cancer burden (RCB), and survival parameters. Thus, our results sustain that AR does not affect the biological behavior of triple-negative BC.

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

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

Molecular Biology Mechanisms and Emerging Therapeutics of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is conventionally characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2), accounting for approximately 15-20% of all breast cancers. Compared to other molecular phenotypes, TNBC is typically associated with high malignancy and poor prognosis. Cytotoxic agents have been the mainstay of treatment for the past few decades due to the lack of definitive targets and limited therapeutic interventions. However, recent developments have demonstrated that TNBC has peculiar molecular classifications and biomarkers, which provide the possibility of evolving treatment from basic cytotoxic chemotherapy to an expanding domain of targeted therapies. This review presents a framework for understanding the current clinical experience surrounding molecular biology mechanisms in TNBC (Figure 1). Including immunotherapy, polymerase (PARP) and PI3K/AKT pathway inhibitors, antibody-drug conjugates, and androgen receptor (AR) blockade. Additionally, the role of miRNA therapeutics targeting TNBC and potential strategies targeting cancer stem cells (CSCs) are discussed and highlighted. As more and more treatments arise on the horizon, we believe that patients with TNBC will have a new sense of hope.

Newly Developed Targeted Therapies Against the Androgen Receptor in Triple-Negative Breast Cancer: A Review

Among different types of breast cancers (BC), triple-negative BC (TNBC) amounts to 15% to 20% of breast malignancies. Three principal characteristics of TNBC cells are (i) extreme aggressiveness, (ii) absence of hormones, and (iii) growth factor receptors. Due to the lack or poor expression of the estrogen receptor, human epidermal growth factor receptor 2, and progesterone receptor, TNBC is resistant to hormones and endocrine therapies. Consequently, chemotherapy is currently used as the primary approach against TNBC. Expression of androgen receptor (AR) in carcinoma cells has been observed in a subset of patients with TNBC; therefore, inhibiting androgen signaling pathways holds promise for TNBC targeting. The new AR inhibitors have opened up new therapy possibilities for BC patients carrying AR-positive TNBC cells. Our group provides a comprehensive review of the structure and function of the AR and clinical evidence for targeting the cell's nuclear receptor in TNBC. We updated AR agonists, inhibitors, and antagonists. We also presented a new era of genetic manipulating CRISPR/Cas9 and nanotechnology as state-of-the-art approaches against AR to promote the efficiency of targeted therapy in TNBC. SIGNIFICANCE STATEMENT: The lack of effective treatment for triple-negative breast cancer is a health challenge. The main disadvantages of existing treatments are their side effects, due to their nonspecific targeting. Molecular targeting of cellular receptors, such as androgen receptors, increased expression in malignant tissues, significantly improving the survival rate of breast cancer patients.

Molecular Classification, Treatment, and Genetic Biomarkers in Triple-Negative Breast Cancer: A Review

Breast cancer is the most common malignancy and the second most common cause of cancer-related mortality in women. Triple-negative breast cancers do not express estrogen receptors, progesterone receptors, or human epidermal growth factor receptor 2 and have a higher recurrence rate, greater metastatic potential, and lower overall survival rate than those of other breast cancers. Treatment of triple-negative breast cancer is challenging; molecular-targeted therapies are largely ineffective and there is no standard treatment. In this review, we evaluate current attempts to classify triple-negative breast cancers based on their molecular features. We also describe promising treatment methods with different advantages and discuss genetic biomarkers and other prediction tools. Accurate molecular classification of triple-negative breast cancers is critical for patient risk categorization, treatment decisions, and surveillance. This review offers new ideas for more effective treatment of triple-negative breast cancer and identifies novel targets for drug development.

Anti-Androgenic Therapies Targeting the Luminal Androgen Receptor of a Typical Triple-Negative Breast Cancer

Triple-negative tumors are progressively delineating their existence over the extended spectrum of breast cancers, marked by intricate molecular heterogeneity, a low overall survival rate, and an unexplored therapeutic approach. Although the basal subtype transcends the group and contributes approximately 80% to triple-negative breast cancer (TNBC) cases, the exceptionally appearing mesenchymal and luminal androgen receptor (LAR) subtypes portray an unfathomable clinical course. LAR with a distinct generic profile frequently metastasizes to regional lymph nodes and bones. This subtype is minimally affected by chemotherapy and shows the lowest pathologic complete response. The androgen receptor is the only sex steroid receptor that plays a cardinal role in the progression of breast cancers and is typically overexpressed in LAR. The partial AR antagonist bicalutamide and the next-generation AR inhibitor enzalutamide are being assessed in standard protocols for the mitigation of TNBC. There arises an inevitable need to probe into the strategies that could neutralize these androgen receptors and alleviate the trajectory of concerning cancer. This paper thus focuses on reviewing literature that provides insights into the anti-androgenic elements against LAR typical TNBC that could pave the way for clinical advancements in this dynamic sphere of oncology.

New Achievements for the Treatment of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) constitutes a heterogeneous group of malignancies that are often aggressive and associated with a poor prognosis. The development of new TNBC treatment strategies has become an urgent clinical need. Diagnosis and subtyping of TNBC are essential to establish alternative treatments and targeted therapies for every TNBC patient. Chemotherapy, particularly with anthracycline and taxanes, remains the backbone for medical management for both early and metastatic TNBC. More recently, immune checkpoint inhibitors and targeted therapy have revolutionized cancer treatment. Included in the different strategies studied for TNBC treatment is drug repurposing. Despite the numerous medications available, numerous studies in medicinal chemistry are still aimed at the synthesis of new compounds in order to find new antiproliferative agents capable of treating TNBC. Additionally, some supplemental micronutrients, nutraceuticals and functional foods can potentially reduce the risk of developing cancer or can retard the rate of growth and metastases of established malignant diseases. Finally, nanotechnology in medicine, termed nanomedicines, introduces nanoparticles of variable chemistry and architecture for cancer treatment. This review highlights the most recent studies in search of new therapies for the treatment of TNBC, along with nutraceuticals and repositioning of drugs.