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The standard treatment for Glioblastoma multiforme (GBM) is surgical resection and subsequent radiotherapy and chemotherapy. Surgical resection of GBM is typically restricted because of its invasive growth, which results in residual tumor cells including glioma stem cells (GSCs) and differentiated cells. Recurrence has been previously thought to occur as a result of these GSCs, and hypoxic microenvironment maintains the GSCs stemness also plays an important role. Summarizing traditional studies and we find many researchers ignored the influence of hypoxia on differentiated cells. We hypothesized that the residual differentiated cells may be dedifferentiated to GSC-like cells under hypoxia and play a crucial role in the rapid, high-frequency recurrence of GBM. Therefore, isolated CD133–CD15–NESTIN– cells were prepared as single-cell culture and treated with hypoxia. More than 95% of the surviving single differentiated CD133–CD15–NESTIN– cell dedifferentiated into tumorigenic CD133+CD15+NESTIN+ GSCs, and this process was regulated by hypoxia inducible factor-1α. Moreover, the serum also played an important role in this dedifferentiation. These findings challenge the traditional glioma cell heterogeneity model, cell division model and glioma malignancy development model. Our study also highlights the mechanism of GBM recurrence and the importance of anti-hypoxia therapy. In addition to GSCs, residual differentiated tumor cells also substantially contribute to treatment resistance and the rapid, high recurrence of GBM.

Chemotherapy plays a significant role in glioma treatment; however, it has limited effectiveness in extending the life expectancies of glioma patients. Traditional studies have attributed this lack of efficacy to glioma stem cells (GSCs) and their high resistance to chemotherapy, and hypoxia worsens this issue. In contrast, hyperoxia effectively alleviates hypoxia in glioma and sensitizes glioma cells to chemotherapy. In a summary of traditional studies, the majority of researchers overlooked the influence of hypoxia on differentiated cells because they only focused on the maintenance of GSCs stemness, which thus resulted in chemoresistance. Because of this background, we hypothesized that GSCs may be induced through dedifferentiation under hypoxic conditions, and hypoxia maintains GSCs stemness, which thus leads to resistance to chemotherapy. In contrast, hyperoxia inhibits the dedifferentiation process and promotes GSCs differentiation, which increases the sensitization of glioma cells to chemotherapy. Hypoxia-inducible factor-1α (HIF1α) contributes substantially to the stemness maintenance of GSCs and resistance of glioma to chemotherapy; thus, we investigated whether HIF1α regulates the resistance or sensitization of glioma cells to chemotherapy in different oxygen levels. It highlights a novel viewpoint on glioma chemosensitivity from the transformation between dedifferentiation and differentiation in different oxygen levels.

Background: Biological pacemakers derived from pluripotent stem cell (PSC) have been considered as a potential therapeutic surrogate for sick sinus syndrome. So it is essential to develop highly efficient strategies for enrichment of sinoatrial node-like cells (SANLCs) as seed cells for biological pacemakers. It has been reported that BMP, FGF, and RA signaling pathways are involved in specification of different cardiomyocyte subtypes, pacemaker, ventricular, and atrial cells. We aimed to investigate whether combined modulation of BMP, FGF, and RA signaling pathways could enrich the differentiation of SANLC from human pluripotent stem cell (hiPSC). Methods: During the differentiation process from human induced pluripotent stem cell to cardiomyocyte through small molecule-based temporal modulation of the Wnt signaling pathway, signaling of BMP, FGF, and RA was manipulated at cardiac mesoderm stage. qRT-PCR, immunofluorescence, flow cytometry, and whole cell patch clamp were used to identify the SANLC.

Previous studies have suggested that hypoxic responses are regulated by hypoxia-inducible factors (HIFs), which in turn promote the malignant progression of glioblastoma (GBM) by inhibiting apoptosis and increasing proliferation; these events lead to a poor prognosis of GBM patients. However, there are still no HIF-targeted therapies for the treatment of GBM. We have conducted series of experiments and discovered that GBM cells exhibit features indicative of malignant progression and are present in a hypoxic environment. Knocking out HIF1α or HIF2α alone resulted in no significant change in cell proliferation and cell cycle progression in response to acute hypoxia, but cells showed inhibition of stemness expression and chemosensitization to temozolomide (TMZ) treatment. However, simultaneously knocking out HIF1α and HIF2α inhibited cell cycle arrest and promoted proliferation with decreased stemness, making GBM cells more sensitive to chemotherapy, which could improve patient prognosis. Thus, HIF1α and HIF2α regulate each other with negative feedback. In addition, HIF1α and HIF2α are upstream regulators of epidermal growth factor (EGF), which controls the malignant development of GBM through the EGFR–PI3K/AKT–mTOR–HIF1α signalling pathway. In brief, the HIF1α/HIF2α–EGF/EGFR–PI3K/AKT–mTOR–HIF1α signalling axis contributes to the growth of GBM through a positive feedback mechanism. Finally, HIF1α and HIF2α regulate Sox2 and Klf4, contributing to stemness expression and inducing cell cycle arrest, thus increasing malignancy in GBM. In summary, HIF1α and HIF2α regulate glioblastoma malignant progression through the EGFR–PI3K/AKT pathway via a positive feedback mechanism under the effects of Sox2 and Klf4, which provides a new tumour development model and strategy for glioblastoma treatment.

Hypoxia-inducible factor 1α (HIF1α) promotes the malignant progression of glioblastoma under hypoxic conditions, leading to a poor prognosis for patients with glioblastoma; however, none of the therapies targeting HIF1α in glioblastoma have successfully eradicated the tumour. Therefore, we focused on the reason and found that treatments targeting HIF1α and HIF2α simultaneously increased tumour volume, but the combination of HIF1α/HIF2α-targeted therapies with temozolomide (TMZ) reduced tumourigenesis and significantly improved chemosensitization. Moreover, miR-210-3p induced HIF1α expression but inhibited HIF2α expression, suggesting that miR-210-3p regulates HIF1α/HIF2α expression. Epidermal growth factor (EGF) has been shown to upregulate HIF1α expression under hypoxic conditions. However, in the present study, in addition to the signalling pathways mentioned above, the upstream proteins HIF1α and HIF2α have been shown to induce EGF expression by binding to the sequences AGGCGTGG and GGGCGTGG. Briefly, in a hypoxic microenvironment the HIF1α/HIF2α-miR210-3p network promotes the malignant progression of glioblastoma through a positive feedback loop with EGF. Additionally, differentiated glioblastoma cells underwent dedifferentiation to produce glioma stem cells under hypoxic conditions, and simultaneous knockout of HIF1α and HIF2α inhibited cell cycle arrest but promoted proliferation with decreased stemness, promoting glioblastoma cell chemosensitization. In summary, both HIF1α and HIF2α regulate glioblastoma cell proliferation, dedifferentiation and chemoresistance through a specific pathway, which is important for glioblastoma treatments.

Chronic bacterial prostatitis (CBP) is an intractable disease. Although bone marrow mesenchymal stem cells (BMMSCs) are able to regulate inflammation in CBP, the effect of microbubble-mediated ultrasound- induced accumulation of BMMSCs on CBP remains unclear. To address this gap, a model of CBP was established in SD rats, which were then treated with BMMSCs alone (BMMSC group), BMMSCs with ultrasound (ultrasound group), BMMSCs with microbubble-mediated ultrasound (MMUS group) and compared with a healthy control group. A therapeutic-ultrasound apparatus was used to treat the prostate in the presence of circulating microbubbles and BMMSCs. The BMMSC distribution was assessed with in vivo imaging, and the prostate structure with light microscopy. Real-time quantitative RT-PCR, ELISA, and immunohistochemistry were used to assess the expressions of TNF-α and IL-1β. More BMMSCs were found in the prostate in the MMUS group than in the CBP, ultrasound, and BMMSC groups. Inflammatory cell infiltration, fibrous tissue hyperplasia, and tumor-like epithelial proliferation were significantly reduced in the MMUS group, as were the mRNA and protein expressions of TNF-α and IL-1β. Microbubble-mediated ultrasound-induced accumulation of BMMSCs can inhibit inflammation and decrease TNF-α and IL-1β expressions in the prostate of CBP rats, suggesting that this method may be therapeutic for CPB.

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