Oncolytic virotherapy is a promising therapeutic strategy that uses replication-competent viruses to selectively destroy malignancies. However, the therapeutic effect of certain oncolytic viruses (OVs) varies among cancer patients. Thus, it is necessary to overcome resistance to OVs through rationally designed combination strategies. Here, through an anticancer drug screening, we show that DNA-dependent protein kinase (DNA-PK) inhibition sensitizes cancer cells to OV M1 and improves therapeutic effects in refractory cancer models in vivo and in patient tumour samples. Infection of M1 virus triggers the transcription of interferons (IFNs) and the activation of the antiviral response, which can be abolished by pretreatment of DNA-PK inhibitor (DNA-PKI), resulting in selectively enhanced replication of OV M1 within malignancies. Furthermore, DNA-PK inhibition promotes the DNA damage response induced by M1 virus, leading to increased tumour cell apoptosis. Together, our study identifies the combination of DNA-PKI and OV M1 as a potential treatment for cancers.

Key points Cardiospheres (CSps) are a promising new form of cardiac stem cells with advantage over other stem cells for myocardial regeneration, but direct implantation of CSps by conventional routes has been limited due to potential embolism.We have implanted CSps into the pericardial cavity and systematically demonstrated its efficacy regarding myocardial infarction.Stem cell potency and cell viability can be optimized in vitro prior to implantation by pre‐conditioning CSps with pericardial fluid and hydrogel packing.Transplantation of optimized CSps into the pericardial cavity improved cardiac function and alleviated myocardial fibrosis, increased myocardial cell survival and promoted angiogenesis.Mechanistically, CSps are able to directly differentiate into cardiomyocytes in vivo and promote regeneration of myocardial cells and blood vessels through a paracrine effect with released growth factors as potential paracrine mediators.These findings establish a new strategy for therapeutic myocardial regeneration to treat myocardial infarction. AbstractCardiospheres (CSps) are a new form of cardiac stem cells with an advantage over other stem cells for myocardial regeneration. However, direct implantation of CSps by conventional routes to treat myocardial infarction has been limited due to potential embolism. We have implanted CSps into the pericardial cavity and systematically assessed its efficacy on myocardial infarction. Preconditioning with pericardial fluid enhanced the activity of CSps and matrix hydrogel prolonged their viability. This shows that pretransplant optimization of stem cell potency and maintenance of cell viability can be achieved with CSps. Transplantation of optimized CSps into the pericardial cavity improved cardiac function and alleviated myocardial fibrosis in the non‐infarcted area, and increased myocardial cell survival and promoted angiogenesis in the infarcted area. Mechanistically, CSps were able to directly differentiate into cardiomyocytes in vivo and promoted regeneration of myocardial cells and blood vessels in the infarcted area through a paracrine effect with released growth factors in pericardial cavity serving as possible paracrine mediators. This is the first demonstration of direct pericardial administration of pre‐optimized CSps, and its effectiveness on myocardial infarction by functional and morphological outcomes with distinct mechanisms. These findings establish a new strategy for therapeutic myocardial regeneration to treat myocardial infarction.

This study provides an efficient method to prepare vascular endothelial growth factor covalent decellularized pericardium scaffold with aspartic acid, and a multilayered bone marrow mesenchymal stem cell (BMSC) sheet is constructed on it using a 3D-dynamic system. The dynamic nutrition supply showed a significant benefit on BMSC bioactivity in vitro, including decreasing cell apoptosis, reducing stem cell differentiation, and improving growth factor secretion. These favorable bioactivity improved BMSC survival, angiogenesis, and cardiac function of the infarcted myocardium. The study highlights the importance of dynamic nutrition supply on maintaining stem cell bioactivity within cell sheet, and it stresses the necessity and significance of setting a standard for assessing cell sheet products before transplantation in the future application.

Accumulating evidence suggests that a subpopulation of stem-cell-like tumor cells in glioma (GSCs) is the major factor accounting for intratumoral heterogeneity and acquired chemotherapeutic resistance. Therefore, understanding intratumoral heterogeneity of GSCs may help develop more effective treatments against this malignancy. However, the study of GSCs’ heterogeneity is highly challenging because tumor stem cells are rare. To overcome the limitation, we employed a microfluidic single-cell culture approach to expand GSCs by taking advantage of the self-renewal property of stem cells. Stemness of the recovered cells was confirmed by immunofluorescence, RT-PCR, RNA-sequencing, and cell function assays. The recovered cells were classified into three groups based on their morphological characteristics, namely, the tight-format (TF), the loose-format (LF), and the limited-size group (LS). The serial passage assay showed that the LS group has a lower sphere-forming rate than the LF and TF group, and the invasion assay showed that the LF and TF cells migrated longer distances in Matrigel. The transcriptomic analysis also revealed differences in gene expression profiling among these GSC subtypes. The abovementioned results suggest that GSCs have transcriptional and functional heterogeneities that correlate with morphological differences. The presented microfluidic single-cell approach links morphology with function and thus can provide an enabling tool for studying tumor heterogeneity.

ClC-3 is a type of chloride channel that has multiple functions in tumorigenesis and tumor growth, and can be blocked by DIDS (4,4'-diisothiocyanostilbene-2,2'-disulfonic acid). In the present study, we found that DIDS inhibited the proliferation of Hep3B hepatocellular carcinoma (HCC) cells in a concentration-dependent manner. More in-depth research demonstrated that DIDS downregulated the protein expression levels of cyclin D1 and cyclin E, which are key proteins of the G1 phase. Additionally, we found that ClC-3 siRNA transfection induced G1 arrest in the Hep3B cells, confirming that ClC-3 is involved in the DIDS-induced inhibition of Hep3B cells. Moreover, the level of α-fetoprotein (AFP), a negative prognostic indicator of HCC, was decreased after treatment with DIDS and ClC-3 siRNA. In conclusion, we demonstrated that ClC-3 can arrest the cell cycle at the G1 phase to inhibit cell proliferation, suggesting that ClC-3 has the potential to be a novel target for HCC therapy and potentially improve the prognosis of HCC patients.