Efficacy of a Novel Mitochondrial-Derived Peptide in a Porcine Model of Myocardial Ischemia/Reperfusion Injury

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A mitochondrial-derived peptide therapy, HNG, was safe and was delivered as adjunctive therapy with standard-of-care reperfusion in a translational large animal model of myocardial ischemia/reperfusion injury.

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HNG reduced infarct size per area-at-risk by 41% with an ischemic time of 60 min followed by 48 h of reperfusion.

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The infarct-sparing effects of HNG were abolished when the ischemic time was increased to 75 min followed by 48 h of reperfusion.

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The use of rigorous translational large animal models that account for clinically relevant variables is a prerequisite to better predict the clinical efficacy and outcomes of novel therapeutic strategies.

With the complexities that surround myocardial ischemia/reperfusion (MI/R) injury, therapies adjunctive to reperfusion that elicit beneficial pleiotropic effects and do not overlap with standard of care are necessary. This study found that the mitochondrial-derived peptide S14G-humanin (HNG) (2 mg/kg), an analogue of humanin, reduced infarct size in a large animal model of MI/R. However, when ischemic time was increased, the infarct-sparing effects were abolished with the same dose of HNG. Thus, although the 60-min MI/R study showed that HNG cardioprotection translates beyond small animal models, further studies are needed to optimize HNG therapy for longer, more patient-relevant periods of cardiac ischemia.

A phase II trial of biweekly vinorelbine and oxaliplatin in second- or third-line metastatic triple-negative breast cancer

Patients with metastatic triple-negative breast cancer (mTNBC) typically have a poor prognosis. The purpose of this study was to prospectively evaluate the efficacy and toxicity of biweekly combination of vinorelbine and oxaliplatin (NVBOX) in second- or third-line setting for mTNBC. Eligible patients were female with 18-70 y old, and had mTNBC that had progressed after 1or 2 prior chemotherapy regimens in the metastatic setting. NVBOX was given biweekly every 4 week for a maximum of 6 cycles. The primary endpoint was progression-free survival (PFS). Forty-4 patients were recruited. All patients had been exposed to anthracyclines and/or taxanes; 56.8% of patients were cis/carbo-platin pretreated. Among the 38 evaluable patients, overall response rate was 31.6% and 7 lasted ≥ 6 months. The median PFS and overall survival (OS) were 4.3 (95% CI, 3.6-5.0) months and 12.6 (95% CI, 8.1-17.0) months, respectively. PFS and OS was significantly shorter in patients with interval from diagnosis to recurrence ≤ 1 y and time to progression (TTP) of 1-2 previous regimens before recruitment ≤ 3 months. For 34 patients who were treated in second line setting, prior platinum was a factor significantly compromising the PFS of NVBOX. Grade 3/4 hematologic toxicities included neutropenia (70.5%), thrombocytopenia (27.3%) and anemia (15.9%). The most frequent grade 3/4 non-hematologic toxicities were constipation/abdominal distension (20.5%) and nausea/vomiting (13.6%). We conclude that biweekly NVBOX regimen is effective with a good safety profile in the second- or third-line mTNBC, which warrants further investigation in a phase III study. This trial was registered with www.clinicaltrials.gov (no. NCT01528826).

Differential potency of regulatory T cell-mediated immunosuppression in kidney tumors compared to subcutaneous tumors

In many cancers, regulatory T cells (Treg) play a crucial role in suppressing the effector immune response thereby permitting tumor development. Indeed, in mouse models, their depletion can promote the regression of tumors of various origins, including renal cell carcinoma when located subcutaneous (SC). In the present study, we aimed to assess the importance of Treg immunosuppression in the physiologic context of metastatic renal carcinoma (Renca) disease. To that purpose we inoculated renal tumors orthotopically, intra-kidney (IK), in mice. Treg depletions were performed using anti-CD4 antibody in wild type mice or diphtheria toxin (DT) in Foxp3^DTR transgenic mice. Our main observation was that Treg were not the key immunosuppressive component of the IK tumoral microenvironment, compared to the same tumors located SC. We demonstrated that the CD8⁺ effector immune response was still suppressed in IK tumors when compared to SC tumors, following Treg depletion. Furthermore, the level of program cell death protein (PD)-1 was increased on the surface of CD4⁺ T cells infiltrating IK tumors compared to SC tumors. Finally, the Treg-independent immunosuppression, occurring in IK tumors, was potent enough to inhibit regression of concomitant SC tumors, normally responsive to Treg depletion. Our findings provide further insight into the immunosuppressive nature of the immune response generated in the kidney microenvironment, suggesting that it can have additional mechanisms in addition to Treg. These observations might help to identify better targets from the kidney tumor microenvironment for future cancer therapies.