IgA Fc-folate conjugate activates and recruits neutrophils to directly target triple-negative breast cancer cells

Folate Metabolism in Hepatocellular Carcinoma. What Do We Know So Far?

Cancer cells are characterized by accelerated proliferation and an outstanding adaptation of their metabolic pathways to meet energy demands. The folate cycle, also known as folate metabolism or one-carbon metabolism, through enzymatic interconversions, provides metabolites necessary for nucleotide synthesis, methylation, and reduction power, helping to maintain the high rate of proliferation; therefore, the study of this metabolic pathway is of great importance in the study of cancer. Moreover, multiple enzymes involved in this cycle have been implicated in different types of cancer, corroborating the cell's adaptations under this pathology. During the last decade, nonalcoholic fatty liver disease has emerged as the leading etiology related to the rise in the incidence and deaths of hepatocellular carcinoma. Specifically, cholesterol accumulation has been a determinant promoter of tumor formation, with solid evidence that an enriched-cholesterol diet plays a crucial role in accelerating the development of an aggressive subtype of hepatocellular carcinoma compared to other models. In this review, we will discuss the most recent findings to understand the contribution of folate metabolism to cancer cells and tumor microenvironment while creating a link between the dynamics given by cholesterol and methylenetetrahydrofolate dehydrogenase 1-like, a key enzyme of the cycle located in the mitochondrial compartment.

Pro- and Anti- Effects of Immunoglobulin A- Producing B Cell in Tumors and Its Triggers

B cells are well known as key mediators of humoral immune responses via the production of antibodies. Immunoglobulin A (IgA) is the most abundantly produced antibody isotype and provides the first line of immune protection at mucosal surfaces. However, IgA has long been a divisive molecule with respect to tumor progression. IgA exerts anti- or pro-tumor effect in different tumor types. In this review, we summarize emerging evidence regarding the production and effects of IgA and IgA⁺ cells in the tumor microenvironment (TME). Moreover, we discuss that the TME cytokines, host diet, microbiome, and metabolites play a pivotal role in controlling the class-switch recombination (CSR) of IgA. The analysis of intratumoral Ig repertoires and determination of metabolites that influence CSR may help establish novel therapeutic targets for the treatment of cancers.

Anti-CD47 Monoclonal Antibody-Drug Conjugate: A Targeted Therapy to Treat Triple-Negative Breast Cancers

Triple-negative breast cancers (TNBCs) are frequently recurrent due to the development of drug resistance post chemotherapy. Both the existing literature and our study found that surface receptor CD47 (cluster of differentiation 47) was upregulated in chemotherapy-treated TNBC cells. The goal of this study was to develop a monoclonal antibody (mAb)-based targeting strategy to treat TNBC after standard treatment. Specifically, a new mAb that targets the extracellular domain of receptor CD47 was developed using hybridoma technology and produced in fed-batch culture. Flow cytometry, confocal microscopy, and in vivo imaging system (IVIS) showed that the anti-CD47 mAb effectively targeted human and mouse TNBC cells and xenograft models with high specificity. The antibody-drug conjugate (ADC) carrying mertansine was constructed and demonstrated higher potency with reduced IC50 in TNBC cells than did the free drug and significantly inhibited tumor growth post gemcitabine treatment in MDA-MB-231 xenograft NSG model. Finally, whole blood analysis indicated that the anti-CD47 mAb had no general immune toxicity, flow cytometry analysis of lymph nodes revealed an increase of CD69+ NK, CD11c+ DC, and CD4+ T cells, and IHC staining showed tumoral infiltration of macrophage in the 4T1 xenograft BALB/cJ model. This study demonstrated that targeting CD47 with ADC has great potential to treat TNBCs as a targeted therapy.

Transcriptome Reprogramming of CD11b+ Bone Marrow Cells by Pancreatic Cancer Extracellular Vesicles

Pancreatic cancers (PC) are highly metastatic with poor prognosis, mainly due to delayed detection. We previously showed that PC-derived extracellular vesicles (EVs) act on macrophages residing in the liver, eliciting extracellular matrix remodeling in this organ and marked hepatic accumulation of CD11b+ bone marrow (BM) cells, which support PC liver metastasis. We here show that PC-EVs also bind to CD11b+ BM cells and induce the expansion of this cell population. Transcriptomic characterization of these cells shows that PC-EVs upregulate IgG and IgA genes, which have been linked to the presence of monocytes/macrophages in tumor microenvironments. We also report here the transcriptional downregulation of genes linked to monocyte/macrophage activation, trafficking, and expression of inflammatory molecules. Together, these results show for the first time the existence of a PC-BM communication axis mediated by EVs with a potential role in PC tumor microenvironments.

Epigenetic Regulation and Dietary Control of Triple Negative Breast Cancer

Triple negative breast cancer (TNBC) represents a highly heterogeneous group of breast cancers, lacking expression of the estrogen (ER) and progesterone (PR) receptors, and human epidermal growth factor receptor 2 (HER2). TNBC are characterized by a high level of mutation and metastasis, poor clinical outcomes and overall survival. Here, we review the epigenetic mechanisms of regulation involved in cell pathways disrupted in TNBC, with particular emphasis on dietary food components that may be exploited for the development of effective strategies for management of TNBC.

A phase II study of Mirvetuximab Soravtansine in triple-negative breast cancer

Folate receptor alpha (FRα) has been reported to be expressed in up to 80% of triple-negative breast cancers (TNBC) with limited expression in normal tissues, making it a promising therapeutic target. Mirvetuximab soravtansine (mirvetuximab-s) is an antibody drug conjugate which has shown promise in the treatment of FRα-positive solid tumors in early phase clinical trials. Herein, are the results of the first prospective phase II trial evaluating mirvetuximab-s in metastatic TNBC. Patients with advanced, FRα-positive TNBC were enrolled on this study. Mirvetuximab-s was administered at a dose of 6.0 mg/kg every 3 weeks. 96 patients with advanced TNBC consented for screening. FRα staining was performed on tumor tissue obtained from 80 patients. The rate of FRα positivity by immunohistochemistry was 10.0% (8/80). Two patients were treated on study, with best overall responses of stable disease in one and progressive disease in the other. Adverse events were consistent with earlier studies. The study was terminated early due to the low rate of FRα positivity in the screened patient population and lack of disease response in the two patients treated. The observed rate of FRα positivity was considerably lower than previously reported and none of the patients had a partial or complete response. Treatment with mirvetuximab-s should only be further explored in TNBC if an alternate biomarker strategy is developed for patient selection on the basis of additional preclinical data.

IgA subclasses have different effector functions associated with distinct glycosylation profiles

Monomeric serum immunoglobulin A (IgA) can contribute to the development of various autoimmune diseases, but the regulation of serum IgA effector functions is not well defined. Here, we show that the two IgA subclasses (IgA1 and IgA2) differ in their effect on immune cells due to distinct binding and signaling properties. Whereas IgA2 acts pro-inflammatory on neutrophils and macrophages, IgA1 does not have pronounced effects. Moreover, IgA1 and IgA2 have different glycosylation profiles, with IgA1 possessing more sialic acid than IgA2. Removal of sialic acid increases the pro-inflammatory capacity of IgA1, making it comparable to IgA2. Of note, disease-specific autoantibodies in patients with rheumatoid arthritis display a shift toward the pro-inflammatory IgA2 subclass, which is associated with higher disease activity. Taken together, these data demonstrate that IgA effector functions depend on subclass and glycosylation, and that disturbances in subclass balance are associated with autoimmune disease.

Immunoglobulin A (IgA) has two subclasses, IgA1 and IgA2, but differential effects on inflammation are unclear. Here the authors show that IgA2, when compared with IgA1, has stronger pro-inflammatory functions associated with changed glycosylation and higher disease scores in patients with rheumatoid arthritis.