RESUMO
Seed deterioration during storage is a major problem in agricultural and forestry production and for germplasm conservation. Our previous studies have shown that a mitochondrial outer membrane protein VOLTAGE-DEPENDENT ANION CHANNEL (VDAC) is involved in programmed cell death (PCD)-like viability loss during the controlled deterioration treatment (CDT) of elm (Ulmus pumila L.) seeds, but its underlying mechanism remains unclear. In this study, we demonstrate that the oxidative modification of GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE (GAPDH) is functioned in the gate regulation of VDAC during the CDT of elm seeds. Through biochemical and cytological methods and observations of transgenic material [Arabidopsis (Arabidopsis thaliana), Nicotiana benthamiana, and yeast (Saccharomyces cerevisiae)], we demonstrate that cysteine S-glutathionylated UpGAPDH1 interacts with UpVDAC3 during seed aging, which leads to a mitochondrial permeability transition and aggravation of cell death, as indicated by the leakage of the mitochondrial pro-apoptotic factor cytochrome c and the emergence of apoptotic nucleus. Physiological assays and inductively coupled plasma mass spectrometry (ICP-MS) analysis revealed that GAPDH glutathionylation is mediated by increased glutathione, which might be caused by increases in the concentrations of free metals, especially Zn. Introduction of the Zn-specific chelator TPEN [(N, N, N', N'-Tetrakis (2-pyridylmethyl)ethylenediamine)] significantly delayed seed aging. We conclude that glutathionylated UpGAPDH1 interacts with UpVDAC3 and serves as a pro-apoptotic protein for VDAC-gating regulation and cell death initiation during seed aging.
RESUMO
OBJECTIVE: The purpose of this retrospective study was to evaluate the clinical and oncological results of combination treatment of short-term preoperative denosumab (the receptor activator of nuclear factor kappa-B ligand inhibitor) with surgery in unresectable or recurrent cases of giant cell tumor of the bone (GCTB). METHODS: Between 2016 and 2018, 11 eligible patients (1 man, 10 women, mean age 38.1 years) with grade 3 GCTB were treated with a combination of short-term (six doses) preoperative denosumab and surgery in a single institution. The clinical, radiological, and pathological alteration after the denosumab treatment were compared. The oncological results of the combination therapy were also recorded. Meanwhile, adverse effects or complications of denosumab, if any, were reported. RESULTS: The median follow-up time after surgical procedure was 30 months (range 13-45 months). After 3-4 denosumab injections, pain relief was observed in all patients. In two spine patients, the neurological status improved after four doses of treatment. Intraoperatively, the margin of the tumor became clear and the intensity of the tumor increased while the blood supply around and within the lesion decreased. Within the lesion, the typically soft and loose tissue were replaced by the tough and dense fibro-osseous tissue. The mean diameter of the lesion before and after treatment was 61.55 ± 22.49 mm and 51.81 ± 21.12 mm, respectively, and the T-score was 1.02 (P = 0.32). Variable calcification was observed at the periphery and within the lesion. A total of three patients experienced local recurrence in this study. In the resection group, only one extremity patient had soft tissue recurrence that was treated with en-bloc excision. In the curettage group, two of three sacral tumor patients had local occurrence. Both refused re-operation and restarted the monthly denosumab injection thereafter, and the lesions remained stable at the final follow up. Finally, no adverse effects or complications related to denosumab treatment were found. CONCLUSION: For the unresectable or recurrent GCTB cases, short-term (six doses) preoperative use of denosumab improved clinical symptoms, decreased the tumor size, and increased the tumor density. The changes in tumors, in turn, simplified the tumor removal manipulation and, subsequently, decreased the local recurrence for the resection surgery. For the curettage, the denosumab-induced changes had mixed impacts, and shorter term (fewer than six doses) usage may be more appropriate. Our six-dose regime was deemed safe, while the safety of long-term use remains unknown.
