Up-regulation of miR-155 protects against chronic heart failure by inhibiting HIF-1α.

BACKGROUND: Despite a crucial role of miR-155 in human cancers, its function in heart failure (HF) is still under investigation. This study was designed to explore its association with HF. METHODS: The abdominal transverse aortic constriction (TAC) was adopted for establishment of mouse HF models. qRT-PCR and WB were adopted to detect the changes of miR-155, HIF-1α, Cle-caspase-3, BCL2 and Bax levels in myocardial cells and heart tissues. The changes of cardiac function were checked by ultrasound. Additionally, luciferase reporter gene was adopted for interaction analysis of miR-155 with HIF-1α, and in situ end labelling method was used for detecting myocardial apoptosis. RESULTS: MiR-155 in myocardial tissue of HF mice was significantly down regulated. In HF mice injected with agomiR-155, the up-regulation of miR-155 strongly improved cardiac function, and also significantly lowered the protein levels of apoptosis-associated markers, C-caspase-3 and Bax, but up regulated Bcl-2. Additionally, HIF-1α was identified as the direct target of miR-155. As expected, over-expression of HIF-1α greatly reversed the effects of agomiR-155 on cardiac function and the expression of apoptosis-associated markers in heart tissues of HF mice. CONCLUSION: MiR-155 overexpression can suppress myocardial cell apoptosis through HIF-1α, and strongly alleviate the cardiac function damage in HF mice, indicating the potential of miR-155/HIF-1α axis to be a target for the diagnosis and therapy of HF.

Cancer Cells Enter an Adaptive Persistence to Survive Radiotherapy and Repopulate Tumor.

Repopulation of residual tumor cells impedes curative radiotherapy, yet the mechanism is not fully understood. It is recently appreciated that cancer cells adopt a transient persistence to survive the stress of chemo- or targeted therapy and facilitate eventual relapse. Here, it is shown that cancer cells likewise enter a "radiation-tolerant persister" (RTP) state to evade radiation pressure in vitro and in vivo. RTP cells are characterized by enlarged cell size with complex karyotype, activated type I interferon pathway and two gene patterns represented by CST3 and SNCG. RTP cells have the potential to regenerate progenies via viral budding-like division, and type I interferon-mediated antiviral signaling impaired progeny production. Depleting CST3 or SNCG does not attenuate the formation of RTP cells, but can suppress RTP cells budding with impaired tumor repopulation. Interestingly, progeny cells produced by RTP cells actively lose their aberrant chromosomal fragments and gradually recover back to a chromosomal constitution similar to their unirradiated parental cells. Collectively, this study reveals a novel mechanism of tumor repopulation, i.e., cancer cell populations employ a reversible radiation-persistence by poly- and de-polyploidization to survive radiotherapy and repopulate the tumor, providing a new therapeutic concept to improve outcome of patients receiving radiotherapy.

COVID-19-another influential event impacts on laboratory medicine management.

BACKGROUND: Before public health emergencies became a major challenge worldwide, the scope of laboratory management was only related to developing, maintaining, improving, and sustaining the quality of accurate laboratory results for improved clinical outcomes. Indeed, quality management is an especially important aspect and has achieved great milestones during the development of clinical laboratories. CURRENT STATUS: However, since the coronavirus disease 2019 (COVID-19) pandemic continues to be a threat worldwide, previous management mode inside the separate laboratory could not cater to the demand of the COVID-19 public health emergency. Among emerging new issues, the prominent challenges during the period of COVID-19 pandemic are rapid-launched laboratory-developed tests (LDTs) for urgent clinical application, rapid expansion of testing capabilities, laboratory medicine resources, and personnel shortages. These related issues are now impacting on clinical laboratory and need to be effectively addressed. CONCLUSION: Different from traditional views of laboratory medicine management that focus on separate laboratories, present clinical laboratory management must be multidimensional mode which should consider consolidation of the efficient network of regional clinical laboratories and reasonable planning of laboratories resources from the view of overall strategy. Based on relevant research and our experience, in this review, we retrospect the history trajectory of laboratory medicine management, and also, we provide existing and other feasible recommended management strategies for laboratory medicine in future.

Necroptosis regulates tumor repopulation after radiotherapy via RIP1/RIP3/MLKL/JNK/IL8 pathway.

BACKGROUND: Tumor cell repopulation after radiotherapy is a major cause for the tumor radioresistance and recurrence. This study aims to investigate the underlying mechanism of tumor repopulation after radiotherapy, with focus on whether and how necroptosis takes part in this process. METHODS: Necroptosis after irradiation were examined in vitro and in vivo. And the growth-promoting effect of necroptotic cells was investigated by chemical inhibitors or shRNA against necroptosis associated proteins and genes in in vitro and in vivo tumor repopulation models. Downstream relevance factors of necroptosis were identified by western blot and chemiluminescent immunoassays. Finally, the immunohistochemistry staining of identified necroptosis association growth stimulation factor was conducted in human colorectal tumor specimens to verify the relationship with clinical outcome. RESULTS: Radiation-induced necroptosis depended on activation of RIP1/RIP3/MLKL pathway, and the evidence in vitro and in vivo demonstrated that the inhibition of necroptosis attenuated growth-stimulating effects of irradiated tumor cells on living tumor reporter cells. The JNK/IL-8 were identified as downstream molecules of pMLKL during necroptosis, and inhibition of JNK, IL-8 or IL-8 receptor significantly reduced tumor repopulation after radiotherapy. Moreover, the high expression of IL-8 was associated with poor clinical prognosis in colorectal cancer patients. CONCLUSIONS: Necroptosis associated tumor repopulation after radiotherapy depended on activation of RIP1/RIP3/MLKL/JNK/IL-8 pathway. This novel pathway provided new insight into understanding the mechanism of tumor radioresistance and repopulation, and MLKL/JNK/IL-8 could be developed as promising targets for blocking tumor repopulation to enhance the efficacy of colorectal cancer radiotherapy.

The Caspase-3/PKCδ/Akt/VEGF-A Signaling Pathway Mediates Tumor Repopulation during Radiotherapy.

PURPOSE: Tumor repopulation is known as a major cause of treatment failure and/or tumor recurrence after radiotherapy. The underlying mechanism remains unclear. Our previous study demonstrated that irradiated apoptotic cells mediated tumor repopulation, in which caspase-3 played an important role. Herein, we investigated downstream effectors of caspase-3 involved in this process. EXPERIMENTAL DESIGN: A dominant-negative protein kinase Cδ (DN_PKCδ) mutant that could not be cleaved by caspase-3 and therefore could not be activated by irradiation-induced apoptosis was constructed. DN_PKCδ stably transduced tumor cells were compared with wild-type tumor cells for their growth stimulation effects in in vitro and in vivo tumor repopulation models. Downstream effectors of caspase-3 and PKCδ were investigated. The role of PKCδ was further verified in human colorectal tumor specimens. RESULTS: Inactivation of caspase-3 or caspase-7 attenuated tumor repopulation and weakened PKCδ cleavage. Both DN_PKCδ and PKCδ inhibitors restrained tumor repopulation both in vitro and in vivo. Phosphorylated Akt was attenuated in caspase-3-, caspase-7-, or PKCδ-inactivated tumor cells. Furthermore, expression of vascular endothelial growth factor (VEGF)-A but not hypoxia-inducible factor 1α (HIF1α) was decreased in PKCδ- or Akt-inactivated tumor cells. In addition, inhibition of p-Akt, HIF1α, VEGF-A, or VEGF-A receptor reduced tumor repopulation significantly. Finally, increased nuclear translocation of PKCδ in colorectal tumor specimens was associated with worse patient prognosis. CONCLUSIONS: The caspase-3/PKCδ/Akt/VEGF-A axis is involved in tumor repopulation and could be exploited as a potential target to enhance the efficacy of radiotherapy.

HMGB1 released by irradiated tumor cells promotes living tumor cell proliferation via paracrine effect.

Tumor repopulation during therapy is an important cause of treatment failure. Strategies to overcome repopulation are arising in parallel with advances in the comprehension of underlying biological mechanisms. Here, we reveal a new mechanism by which high mobility group box 1 (HMGB1) released by dying cells during radiotherapy or chemotherapy could stimulate living tumor cell proliferationInhibition or genetic ablation of HMGB1 suppressed tumor cell proliferation. This effect was due to binding of HMGB1with the member receptor for advanced glycation end-products (RAGE), which activated downstream ERK and p38 signaling pathway and promoted cell proliferation. Furthermore, higher HMGB1 expression in tumor tissue correlated with poor overall survival and higher HMGB1 concentration was detected in serum of patients who accepted radiotherapy. Collectively, the results from this study suggested that interaction between dead cells and surviving cells might influence the fate of tumor. HMGB1 could be a novel tumor promoter with therapeutic and prognostic relevance in cancers.

Metformin: a review of its potential indications.

Metformin is the most commonly prescribed drug for type 2 diabetes mellitus. In recent years, in addition to glucose lowering, several studies have presented evidence suggesting some potential role for metformin, such as antitumor effect, antiaging effect, cardiovascular protective effect, neuroprotective effect or an optional treatment for polycystic ovary syndrome. This paper will critically review the role of metformin to provide reference for doctors and researchers.