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MDM2 has been established as a biomarker indicating poor prognosis for individuals undergoing immune checkpoint inhibitor (ICI) treatment for different malignancies by various pancancer studies. Specifically, patients who have MDM2 amplification are vulnerable to the development of hyperprogressive disease (HPD) following anticancer immunotherapy, resulting in marked deleterious effects on survival rates. The mechanism of MDM2 involves its role as an oncogene during the development of malignancy, and MDM2 can promote both metastasis and tumor cell proliferation, which indirectly leads to disease progression. Moreover, MDM2 is vitally involved in modifying the tumor immune microenvironment (TIME) as well as in influencing immune cells, eventually facilitating immune evasion and tolerance. Encouragingly, various MDM2 inhibitors have exhibited efficacy in relieving the TIME suppression caused by MDM2. These results demonstrate the prospects for breakthroughs in combination therapy using MDM2 inhibitors and anticancer immunotherapy. [ABSTRACT FROM AUTHOR]

It remains unclear whether metronomic chemotherapy is superior to conventional chemotherapy when combined with immune checkpoint blockade. Here we performed a phase 2 clinical trial of metronomic chemotherapy combined with PD-1 blockade to compare the efficacy of combined conventional chemotherapy and PD-1 blockade using Bayesian adaptive randomization and efficacy monitoring. Eligible patients had metastatic HER2-negative breast cancer and had not received more than one prior line of standard chemotherapy. Patients (total n = 97) were randomized to receive (1) metronomic vinorelbine (NVB) monotherapy (n = 11), (2) NVB plus anti-PD-1 toripalimab (n = 7), (3) anti-angiogenic bevacizumab, NVB and toripalimab (n = 27), (4) conventional cisplatin, NVB and toripalimab (n = 26), or (5) metronomic cyclophosphamide, capecitabine, NVB and toripalimab (the VEX cohort) (n = 26). The primary endpoint was disease control rate (DCR). Secondary objectives included progression-free survival (PFS) and safety. The study met the primary endpoint. The VEX (69.7%) and cisplatin (73.7%) cohorts had the highest DCR. The median PFS of patients in the VEX cohort was the longest, reaching 6.6 months, followed by the bevacizumab (4.0 months) and cisplatin (3.5 months) cohorts. In general, the five regimens were well tolerated, with nausea and neutropenia being the most common adverse events. An exploratory mass cytometry analysis indicated that metronomic VEX chemotherapy reprograms the systemic immune response. Together, the clinical and translational data of this study indicate that metronomic VEX chemotherapy combined with PD-1 blockade can be a treatment option in patients with breast cancer. ClinicalTrials.gov Identifier: NCT04389073 ., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Metastasis-associated 1 (MTA1), a subunit of the nucleosome remodeling and histone deacetylation (NuRD) corepressor complex, was reported to be expressed in the cytoplasm of skeletal muscles. However, the exact subcellular localization and the functional implications of MTA1 in skeletal muscles have not been examined. This study aims to demonstrate the subcellular localization of MTA1 in skeletal muscles and reveal its possible roles in skeletal muscle pathogenesis. Striated muscles (skeletal and cardiac) from C57BL/6 mice of 4-5 weeks were collected to examine the expression of MTA1 by Western blotting and immunohistochemistry. Immunofluorescence and immunoelectron microscopy were performed for MTA1, α-actinin (a Z-disc marker protein), and SMN (survival of motor neuron) proteins. Gene Expression Omnibus (GEO) data sets were analyzed using the GEO2R online tool to explore the functional implications of MTA1 in skeletal muscles. MTA1 expression was detected by Western blotting and immunohistochemistry in skeletal and cardiac muscles. Subcellular localization of MTA1 was found in the Z-disc of sarcomeres, where α-actinin and SMN were expressed. Data mining of GEO profiles suggested that MTA1 dysregulation is associated with multiple skeletal muscle defects, such as Duchenne muscular dystrophy, Emery-Dreifuss muscular dystrophy, nemaline myopathy, and dermatomyositis. The GEO analysis also showed that MTA1 expression gradually decreased with age in mouse skeletal muscle precursor cells. The subcellular localization of MTA1 in sarcomeres of skeletal muscles implies its biological roles in sarcomere structures and its possible contribution to skeletal muscle pathology., (© 2024 Wiley Periodicals LLC.)