Aims Doxorubicin is widely used against cancer; however, it can produce heart failure (HF). Among other hallmarks, oxidative stress is a major contributor to HF pathophysiology. The late I_Na inhibitor ranolazine has proven effective in treating experimental HF. Since elevated [Na⁺]_i is present in failing myocytes, and has been recently linked with reactive oxygen species (ROS) production, our aim was to assess whether ranolazine prevents doxorubicin-induced cardiotoxicity, and whether blunted oxidative stress is a mechanism accounting for such protection. Methods and result In C57BL6 mice, doxorubicin treatment for 7 days produced LV dilation and decreased echo-measured fractional shortening (FS). Ranolazine (305 mg/kg/day) prevented LV dilation and dysfunction when co-administered with doxorubicin. Doxorubicin-induced cardiotoxicity was accompanied instead by elevations in atrial natriuretic peptide (ANP), BNP, connective tissue growth factor (CTGF), and matrix metalloproteinase 2 (MMP2) mRNAs, which were not elevated on co-treatment with ranolazine. Alterations in extracellular matrix remodelling were confirmed by an increase in interstitial collagen, which did not rise in ranolazine-co-treated hearts. Levels of poly(ADP-ribose) polymerase (PARP) and pro-caspase-3 measured by western blotting were lowered with doxorubicin, with increased cleavage of caspase-3, indicating activation of the proapoptotic machinery. Again, ranolazine prevented this activation. Furthermore, in HL-1 cardiomyocytes transfected with HyPer to monitor H₂O₂ emission, besides reducing the extent of cell death, ranolazine prevented the occurrence of oxidative stress caused by doxorubicin. Interestingly, similar protective results were obtained with the Na⁺/Ca²⁺ exchanger (NCX) inhibitor KB-R7943. Conclusions Ranolazine protects against experimental doxorubicin cardiotoxicity. Such protection is accompanied by a reduction in oxidative stress, suggesting that I_Na modulates cardiac redox balance, resulting in functional and morphological derangements.

The antibody trastuzumab, targeted to inhibit the signalling of ErbB2, a tyrosine kinase receptor overexpressed in 20–30% of breast cancers, improves the prognosis in women affected by this tumour, but produces cardiotoxicity, since ErbB2 is also involved in myocardial homeostasis. In this review, we discuss the pathophysiology of trastuzumab cardiomyopathy and the complex interplay between ErbB2 inhibition and anthracyclines, and we focus on the actual challenges of detecting, monitoring, and managing trastuzumab cardiotoxicity: the research of new, sensitive markers of early trastuzumab toxicity, before the ejection fraction is reduced, is an active field of research.

Significance: Because of its selective expression on the surface of a variety of different cancer cells, but not on their normal counterparts, nucleolin (NCL) represents an attractive target for antineoplastic treatments. However, previously described NCL-targeting molecules, although promising, still suffer from intrinsic limitations. Here, we describe the identification of the first fully human anti-NCL immune-based agent displaying antineoplastic activity against solid tumors, both in vitro and in vivo. This molecule could represent the prototype of a novel class of NCL-targeting drugs with enormous clinical potential as tools for the diagnosis and therapy of a wide range of human cancers.

Several ribonucleases serve as cytotoxic agents in host defense and in physiological cell death pathways. Although certain members of the pancreatic ribonuclease A superfamily can be toxic when applied to the outside of cells, they become thousands of times more toxic when artificially introduced into the cytosol, indicating that internalization is the rate-limiting step for cytotoxicity. We have used three agents that disrupt the Golgi apparatus by distinct mechanisms, retinoic acid, brefeldin A, and monensin, to probe the intracellular pathways ribonucleases take to reach the cytosol. Retinoic acid and monensin potentiate the cytotoxicity of bovine seminal RNase, Onconase, angiogenin, and human ribonuclease A 100 times or more. Retinoic acid-mediated potentiation of ribonucleases is completely blocked by brefeldin A. Ribonucleases appear to route more efficiently into the cytosol through the Golgi apparatus disrupted by monensin or retinoic acid. Intracellular RNA degradation by BS-RNase increased more than 100 times in the presence of retinoic acid confirming that the RNase reaches the cytosol and indicating that degradation of RNA is the intracellular lesion causing toxicity. As retinoic acid alone and Onconase are in clinical trials for cancer therapy, combinations of RNases and retinoic acid in vivo may offer new clinical utility.

Background: Triple-negative breast cancer (TNBC) is a uniquely aggressive cancer with high rates of relapse due to resistance to chemotherapy. TNBC expresses higher levels of programmed cell death-ligand 1 (PD-L1) compared to other breast cancers, providing the rationale for the recently approved immunotherapy with anti-PD-L1 monoclonal antibodies (mAbs). A huge effort is dedicated to identify actionable biomarkers allowing for combination therapies with immune-checkpoint blockade. Platelet-derived growth factor receptor β (PDGFRβ) is highly expressed in invasive TNBC, both on tumor cells and tumor microenvironment. We recently proved that tumor growth and lung metastases are impaired in mouse models of human TNBC by a high efficacious PDGFRβ aptamer. Hence, we aimed at investigating the effectiveness of a novel combination treatment with the PDGFRβ aptamer and anti-PD-L1 mAbs in TNBC.Methods: The targeting ability of the anti-human PDGFRβ aptamer toward the murine receptor was verified by streptavidin-biotin assays and confocal microscopy, and its inhibitory function by transwell migration assays. The anti-proliferative effects of the PDGFRβ aptamer/anti-PD-L1 mAbs combination was assessed in human MDA-MB-231 and murine 4 T1 TNBC cells, both grown as monolayer or co-cultured with lymphocytes. Tumor cell lysis and cytokines secretion by lymphocytes were analyzed by LDH quantification and ELISA, respectively. Orthotopic 4 T1 xenografts in syngeneic mice were used for dissecting the effect of aptamer/mAb combination on tumor growth, metastasis and lymphocytes infiltration. Ex vivo analyses through immunohistochemistry, RT-qPCR and immunoblotting were performed.Results: We show that the PDGFRβ aptamer potentiates the anti-proliferative activity of anti-PD-L1 mAbs on both human and murine TNBC cells, according to its human/mouse cross-reactivity. Further, by binding to activated human and mouse lymphocytes, the aptamer enhances the anti-PD-L1 mAb-induced cytotoxicity of lymphocytes against tumor cells. Importantly, the aptamer heightens the antibody efficacy in inhibiting tumor growth and lung metastases in mice. It acts on both tumor cells, inhibiting Akt and ERK1/2 signaling pathways, and immune populations, increasing intratumoral CD8 + T cells and reducing FOXP3 + Treg cells.Conclusion: Co-treatment of PDGFRβ aptamer with anti-PD-L1 mAbs is a viable strategy, thus providing for the first time an evidence of the efficacy of PDGFRβ/PD-L1 co-targeting combination therapy in TNBC.