Cyclophosphamide alters the tumor cell secretome to potentiate the anti-myeloma activity of daratumumab through augmentation of macrophage-mediated antibody dependent cellular phagocytosis

Enhanced potency of immunotherapy against B-cell precursor acute lymphoblastic leukemia by combination of an Fc-engineered CD19 antibody and CD47 blockade

CD19-directed immunotherapy has become a cornerstone in the therapy of B-cell precursor acute lymphoblastic leukemia (BCP-ALL). CD19-directed cellular and antibody-based therapeutics have entered therapy of primary and relapsed disease and contributed to improved outcomes in relapsed disease and lower therapy toxicity. However, efficacy remains limited in many cases due to a lack of therapy response, short remission phases, or antigen escape. Here, BCP-ALL cell lines, patient-derived xenograft (PDX) samples, human macrophages, and an in vivo transplantation model in NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice were used to examine the therapeutic potency of a CD19 antibody Fc-engineered for improved effector cell recruitment (CD19-DE) and antibody-dependent cellular phagocytosis (ADCP), in combination with a novel modified CD47 antibody (Hu5F9-IgG2σ). For the in vivo model, only samples refractory to CD19-DE monotherapy were chosen. Hu5F9-IgG2σ enhanced ADCP by CD19-DE in various BCP-ALL cell line models with varying CD19 surface expression and cytogenetic backgrounds, two of which contained the KMT2A-AFF1 fusion. Also, the antibody combination was efficient in inducing ADCP by human macrophages in pediatric PDX samples with and adult samples with and without KMT2A-rearrangement in vitro. In a randomized phase 2-like PDX trial using seven KMT2A-rearranged BCP-ALL samples in NSG mice, the CD19/CD47 antibody combination proved highly efficient. Our findings support that the efficacy of Fc-engineered CD19 antibodies may be substantially enhanced by a combination with CD47 blockade. This suggests that the combination may be a promising therapy option for BCP-ALL, especially in relapsed patients and/or patients refractory to CD19-directed therapy.

Anti-Tumor Strategies by Harnessing the Phagocytosis of Macrophages

Macrophages are essential for the human body in both physiological and pathological conditions, engulfing undesirable substances and participating in several processes, such as organism growth, immune regulation, and maintenance of homeostasis. Macrophages play an important role in anti-bacterial and anti-tumoral responses. Aberrance in the phagocytosis of macrophages may lead to the development of several diseases, including tumors. Tumor cells can evade the phagocytosis of macrophages, and "educate" macrophages to become pro-tumoral, resulting in the reduced phagocytosis of macrophages. Hence, harnessing the phagocytosis of macrophages is an important approach to bolster the efficacy of anti-tumor treatment. In this review, we elucidated the underlying phagocytosis mechanisms, such as the equilibrium among phagocytic signals, receptors and their respective signaling pathways, macrophage activation, as well as mitochondrial fission. We also reviewed the recent progress in the area of application strategies on the basis of the phagocytosis mechanism, including strategies targeting the phagocytic signals, antibody-dependent cellular phagocytosis (ADCP), and macrophage activators. We also covered recent studies of Chimeric Antigen Receptor Macrophage (CAR-M)-based anti-tumor therapy. Furthermore, we summarized the shortcomings and future applications of each strategy and look into their prospects with the hope of providing future research directions for developing the application of macrophage phagocytosis-promoting therapy.

Bispecific Antibodies in Multiple Myeloma: Opportunities to Enhance Efficacy and Improve Safety

Multiple myeloma (MM) is the second most common haematological neoplasm of adults in the Western world. Overall survival has doubled since the advent of proteosome inhibitors (PIs), immunomodulatory agents (IMiDs), and monoclonal antibodies. However, patients with adverse cytogenetics or high-risk disease as determined by the Revised International Staging System (R-ISS) continue to have poorer outcomes, and triple-refractory patients have a median survival of less than 1 year. Bispecific antibodies (BsAbs) commonly bind to a tumour epitope along with CD3 on T-cells, leading to T-cell activation and tumour cell killing. These treatments show great promise in MM patients, with the first agent, teclistamab, receiving regulatory approval in 2022. Their potential utility is hampered by the immunosuppressive tumour microenvironment (TME), a hallmark of MM, which may limit efficacy, and by undesirable adverse events, including cytokine release syndrome (CRS) and infections, some of which may be fatal. In this review, we first consider the means of enhancing the efficacy of BsAbs in MM. These include combining BsAbs with other drugs that ameliorate the effect of the immunosuppressive TME, improving target availability, the use of BsAbs directed against multiple target antigens, and the optimal time in the treatment pathway to employ BsAbs. We then discuss methods to improve safety, focusing on reducing infection rates associated with treatment-induced hypogammaglobulinaemia, and decreasing the frequency and severity of CRS. BsAbs offer a highly-active therapeutic option in MM. Improving the efficacy and safety profiles of these agents may enable more patients to benefit from these novel therapies and improve outcomes for patients with high-risk disease.

Inflammation-related mRNA expression in patients with multiple myeloma undergoing hematopoietic stem cell mobilization

Mobilization of CD34+ cells is a key element in the therapy of patients with multiple myeloma undergoing autologous stem cell transplantation. The use of chemotherapy and the granulocyte colony-stimulating factor can significantly affect the expression of inflammation-related proteins and the migration of hematopoietic stem cells. We assessed the mRNA expression of selected proteins involved in the inflammatory landscape in MM patients (n=71). The aim of the study was to evaluate C-C motif chemokine ligand 3, 4, 5 (CCL3, CCL4, CCL5), leukocyte cell-derived chemotaxin 2 (LECT2), tumor necrosis factor (TNF), and formyl peptide receptor 2 (FPR2) levels in the course of mobilization and their role in the CD34+ collection efficacy. mRNA expression from peripheral blood plasma was evaluated by RT-PCR. We observed a deep decline in CCL3, CCL4, LECT2, and TNF mRNA expression on the day of the first apheresis (day A) as compared to baseline. A negative correlation was observed between CCL3, FPR2, LECT2, TNF level, and the CD34+ cells count in peripheral blood on day A, and the number of CD34+ cells obtained at first apheresis . Our results indicate that the investigated mRNAs significantly alter and may regulate the migration of CD34+ cells during mobilization. Moreover, in case of FPR2 and LECT2, the results obtained in patients differ from the murine models.

Tumor-Associated Macrophages and Related Myelomonocytic Cells in the Tumor Microenvironment of Multiple Myeloma

Multiple myeloma (MM) is the second-most common hematologic malignancy and remains incurable despite potent plasma cell directed therapeutics. The tumor microenvironment (TME) is a key player in the pathogenesis and progression of MM and is an active focus of research with a view to targeting immune dysregulation. Tumor-associated macrophages (TAM), myeloid derived suppressor cells (MDSC), and dendritic cells (DC) are known to drive progression and treatment resistance in many cancers. They have also been shown to promote MM progression and immune suppression in vitro, and there is growing evidence of their impact on clinical outcomes. The heterogeneity and functional characteristics of myelomonocytic cells in MM are being unraveled through high-dimensional immune profiling techniques. We are also beginning to understand how they may affect and be modulated by current and future MM therapeutics. In this review, we provide an overview of the biology and clinical relevance of TAMs, MDSCs, and DCs in the MM TME. We also highlight key areas to be addressed in future research as well as our perspectives on how the myelomonocytic compartment of the TME may influence therapeutic strategies of the future.

CyBorD-DARA in Newly Diagnosed Transplant-Eligible Multiple Myeloma: Results from the 16-BCNI-001/CTRIAL-IE 16-02 Study Show High Rates of MRD Negativity at End of Treatment

The phase 1b 16-BCNI-001/CTRIAL-IE 16-02 CyBorD-DARA trial investigated the combination of Daratumumab with cyclophosphamide, bortezomib and dexamethasone in patients with newly diagnosed multiple myeloma (NDMM), followed by autologous stem cell transplantation and Daratumumab maintenance. CR/sCR rates were 50% after transplant and 62.5% at end of treatment. The overall percentage of patients achieving complete response or better was 77.8%. Progression-free survival rate at end of maintenance was 81.3% and estimated 2-year overall survival was 88.9%. 37.5% of patients demonstrated sustained MRD negativity to a level of 10^-5 from transplant to analysis at EOT. In this phase 1b study, we have shown CyBorD-DARA to be an effective and well-tolerated immunomodulatory agent-free regiment in transplant-eligible NDMM.

Vascular normalization and immunotherapy: Spawning a virtuous cycle

Anti-angiogenics, radiotherapy (especially stereotactic body radiotherapy, SBRT)/chemotherapy, and immunotherapy form a critical trimodal approach in modern cancer therapy. The normalization window, however short, is the beachhead for the strategic initiation of a decipherable disruption of cancer cells. This opening can be the opportunity for designing controlled stepwise cancer cell death (CCD) and immunological augmentation. The next step is to induce immunogenic cell death (ICD) through chemotherapy/radiotherapy concurrently with the facilitation of professional phagocytosis. Immunotherapy at this stage, when interstitial pressure decreases considerably, leads to the improved perfusion of oxygen with solutes and improved immune-friendly pH and is additionally expected to open up the tumor microenvironment (TME) for a “flood” of tumor-infiltrating lymphocytes. Furthermore, there would be enhanced interaction in “hot” nodules and the incorporation of immune reaction in “cold” nodules. Simultaneously, the added adjuvant-assisted neoantigen–immune cell interaction will likely set in a virtuous cycle of CCD induction followed by tumor cell-specific antigenic reaction boosting CCD, in turn promoting the normalization of the vasculature, completing the loop. There should be a conscious concern to protect the extracellular matrix (ECM), which will nurture the long-term immunological cross-talk to discourage dormancy, which is as essential as obtaining a complete response in imaging. The caveat is that the available therapies should be appropriately ranked during the start of the treatment since the initial administration is the most opportune period. A fast-paced development in the nanomedicine field is likely to assist in all the steps enumerated.

Low anti-CFL1 antibody with high anti-ACTB antibody is a poor prognostic factor in esophageal squamous cell carcinoma

BACKGROUND

Cofilin (CFL1, actin-binding protein) and β-actin (ACTB) are key molecules in the polymerization and depolymerization of actin microfilaments. The levels of these antibodies were analyzed, and the clinicopathological significance in patients with esophageal carcinoma were evaluated.

METHODS

The levels of anti-CFL1 and anti-ACTB antibodies were analyzed in serum samples of patients with esophageal carcinoma and of healthy donors. Eighty-seven cases underwent radical surgery and the clinicopathological characteristics and prognosis was examined.

RESULTS

Serum anti-CFL1 antibody (s-CFL1-Ab) levels and anti-ACTB antibody (s-ACTB-Ab) levels were significantly higher in patients with esophageal carcinoma than in healthy donors. Following the receiver operating characteristic curve analysis between healthy donors and esophageal carcinoma, the sensitivity and specificity for serum anti-CFL1 antibody (s-CFL1-Ab) were 53.3% and 68.8%. The sensitivity and specificity for serum anti-ACTB antibody (s-ACTB-Ab) were 54.9% and 67.7%, respectively. Univariate and multivariate analysis showed that s-CFL1-Ab and s-ACTB-Ab levels were not associated with sex, age, tumor depth, lymph node metastasis, or anti-p53-antibody levels. s-ACTB-Ab levels but not s-CFL1-Ab levels significantly correlated with squamous cell carcinoma antigen. Neither s-CFL1-Ab nor s-ACTB-Ab levels alone were obviously related to overall survival. However, patients with low s-CFL1-Ab levels and high s-ACTB-Ab levels exhibited significantly more unfavorable prognoses than those with high s-CFL1-Ab and low s-ACTB-Ab levels.

CONCLUSIONS

Serum levels of anti-CFL1 and anti-ACTB antibodies were significantly higher in patients with esophageal carcinoma than in healthy donors. A combination of low anti-CFL1 and high anti-ACTB antibodies is a poor prognostic factor in esophageal carcinoma.

The protective effects of rutin on the liver, kidneys, and heart by counteracting organ toxicity caused by synthetic and natural compounds

Rutin is a flavonoid present in many plant species. Because of its antioxidant, anti-inflammatory, and antiapoptotic properties, rutin is of interest for its potential protective effects against toxic agents. The hepatoprotective, renoprotective, and cardioprotective effects of rutin are reviewed. The antioxidant effects of rutin are elicited by enhancing antioxidant enzymes such as GST, GGT, CAT, GPx, SOD, and GR, activating the Nrf2/HO-1 pathway, elevating GSH content, and the reduction in MDA. The anti-inflammatory effects of rutin are mediated by the inhibition of IL-1β, IL-6, TGF-β1, COX-2, iNOS, TLR4, and XO. Rutin exerted its antiapoptotic effects by inhibition of free radicals, caspase-3/-7/-9, hsp70, HMGB1, and p53, and the elevation of the antiapoptotic protein Bcl-2. Rutin has potential therapeutic effectiveness against several toxicants, and its beneficial effects are more than likely mediated by its antioxidant, anti-inflammatory, and/or antiapoptotic property.

Extracellular vesicles and PDL1 suppress macrophages inducing therapy resistance in TP53-deficient B-cell malignancies

Genetic alterations in the DNA Damage Response (DDR) pathway are a frequent mechanism of resistance to CIT in B-cell malignancies. We have previously shown that the synergy of CIT relies on secretory crosstalk elicited by chemotherapy between the tumour cells and macrophages. Here, we show that loss of multiple different members of the DDR pathway inhibits macrophage phagocytic capacity in vitro and in vivo. Particularly loss of TP53 led to decreased phagocytic capacity ex vivo across multiple B-cell malignancies. We demonstrate via in vivo cyclophosphamide treatment using the Eµ-TCL1 mouse model that loss of macrophage phagocytic capacity in Tp53-deleted leukemia is driven by a significant downregulation of a phagocytic transcriptomic signature using scRNA-Seq. By analysing the tumour B-cell proteome, we identified a TP53 specific upregulation of proteins associated with extracellular vesicles (EV). We abrogated EV biogenesis in tumour B-cells via CRISPR-knockout (KO) of RAB27A and confirmed that the EVs from TP53-deleted lymphoma cells were responsible for the reduced phagocytic capacity and the in vivo CIT resistance. Furthermore, we observed that TP53 loss led to an upregulation of both PD-L1 cell surface expression and secretion of EVs by lymphoma cells. Disruption of EV bound PD-L1 by anti-PD-L1 antibodies or PD-L1 CRISPR-KO improved macrophage phagocytic capacity and in vivo therapy response. Thus, we demonstrate enhanced EV-release and increased PD-L1 expression in TP53-deficient B-cell lymphomas as novel mechanisms of macrophage function alteration in CIT resistance. This study indicates the use of checkpoint inhibition in the combination treatment of B-cell malignancies with TP53 loss.

Mechanisms of Immune Evasion in Multiple Myeloma: Open Questions and Therapeutic Opportunities

Multiple myeloma (MM) is the second most common hematologic malignancy, characterized by a multi-step evolutionary path, which starts with an early asymptomatic stage, defined as monoclonal gammopathy of undetermined significance (MGUS) evolving to overt disease in 1% of cases per year, often through an intermediate phase known as "smoldering" MM (sMM). Interestingly, while many genomic alterations (translocation, deletions, mutations) are usually found at early stages, they are not sufficient (alone) to determine disease evolution. The latter, indeed, relies on significant "epigenetic" alterations of different normal cell populations within the bone marrow (BM) niche, including the "evasion" from immune-system control. Additionally, MM cells could "educate" the BM immune microenvironment (BM-IM) towards a pro-inflammatory and immunosuppressive phenotype, which ultimately leads to disease evolution, drug resistance, and patients' worse outcome. Indeed, it is not a case that the most important drugs for the treatment of MM include immunomodulatory agents (thalidomide, lenalidomide, and pomalidomide) and monoclonal antibodies (daratumumab, isatuximab, and elotuzumab). On these bases, in this review, we describe the most recent advances in the comprehension of the role of the different cells composing the BM-IM, and we discuss the potential molecular targets, which could represent new opportunities to improve current treatment strategies for MM patients.