2-Hydroxy-3-methylanthraquinone inhibits homologous recombination repair in osteosarcoma through the MYC-CHK1-RAD51 axis.

BACKGROUND: Osteosarcoma is a malignant bone tumor that usually affects adolescents aged 15-19 y. The DNA damage response (DDR) is significantly enhanced in osteosarcoma, impairing the effect of systemic chemotherapy. Targeting the DDR process was considered a feasible strategy benefitting osteosarcoma patients. However, the clinical application of DDR inhibitors is not impressive because of their side effects. Chinese herbal medicines with high anti-tumor effects and low toxicity in the human body have gradually gained attention. 2-Hydroxy-3-methylanthraquinone (HMA), a Chinese medicine monomer found in the extract of Oldenlandia diffusa, exerts significant inhibitory effects on various tumors. However, its anti-osteosarcoma effects and defined molecular mechanisms have not been reported. METHODS: After HMA treatment, the proliferation and metastasis capacity of osteosarcoma cells was detected by CCK-8, colony formation, transwell assays and Annexin V-fluorescein isothiocyanate/propidium iodide staining. RNA-sequence, plasmid infection, RNA interference, Western blotting and immunofluorescence assay were used to investigate the molecular mechanism and effects of HMA inhibiting osteosarcoma. Rescue assay and CHIP assay was used to further verified the relationship between MYC, CHK1 and RAD51. RESULTS: HMA regulate MYC to inhibit osteosarcoma proliferation and DNA damage repair through PI3K/AKT signaling pathway. The results of RNA-seq, IHC, Western boltting etc. showed relationship between MYC, CHK1 and RAD51. Rescue assay and CHIP assay further verified HMA can impair homologous recombination repair through the MYC-CHK1-RAD51 pathway. CONCLUSION: HMA significantly inhibits osteosarcoma proliferation and homologous recombination repair through the MYC-CHK1-RAD51 pathway, which is mediated by the PI3K-AKT signaling pathway. This study investigated the exact mechanism of the anti-osteosarcoma effect of HMA and provided a potential feasible strategy for the clinical treatment of human osteosarcoma.

Ferroptosis as a novel form of regulated cell death: Implications in the pathogenesis, oncometabolism and treatment of human cancer.

The treatment of cancer mainly involves surgical excision supplemented by radiotherapy and chemotherapy. Chemotherapy drugs act by interfering with tumor growth and inducing the death of cancer cells. Anti-tumor drugs were developed to induce apoptosis, but some patient's show apoptosis escape and chemotherapy resistance. Therefore, other forms of cell death that can overcome the resistance of tumor cells are important in the context of cancer treatment. Ferroptosis is a newly discovered iron-dependent, non-apoptotic type of cell death that is highly negatively correlated with cancer development. Ferroptosis is mainly caused by the abnormal increase in iron-dependent lipid reactive oxygen species and the imbalance of redox homeostasis. This review summarizes the progression and regulatory mechanism of ferroptosis in cancer and discusses its possible clinical applications in cancer diagnosis and treatment.

Proper animal experimental designs for preclinical research of biomaterials for intervertebral disc regeneration.

Low back pain is a vital musculoskeletal disease that impairs life quality, leads to disability and imposes heavy economic burden on the society, while it is greatly attributed to intervertebral disc degeneration (IDD). However, the existing treatments, such as medicines, chiropractic adjustments and surgery, cannot achieve ideal disc regeneration. Therefore, advanced bioactive therapies are implemented, including stem cells delivery, bioreagents administration, and implantation of biomaterials etc. Among these researches, few reported unsatisfying regenerative outcomes. However, these advanced therapies have barely achieved successful clinical translation. The main reason for the inconsistency between satisfying preclinical results and poor clinical translation may largely rely on the animal models that cannot actually simulate the human disc degeneration. The inappropriate animal model also leads to difficulties in comparing the efficacies among biomaterials in different reaches. Therefore, animal models that better simulate the clinical charateristics of human IDD should be acknowledged. In addition, in vivo regenerative outcomes should be carefully evaluated to obtain robust results. Nevertheless, many researches neglect certain critical characteristics, such as adhesive properties for biomaterials blocking annulus fibrosus defects and hyperalgesia that is closely related to the clinical manifestations, e.g., low back pain. Herein, in this review, we summarized the animal models established for IDD, and highlighted the proper models and parameters that may result in acknowledged IDD models. Then, we discussed the existing biomaterials for disc regeneration and the characteristics that should be considered for regenerating different parts of discs. Finally, well-established assays and parameters for in vivo disc regeneration are explored.

A rat model of vascular dementia for evaluating Chinese medicine prescriptions.

OBJECTIVE: To develop a new model of vascular dementia for evaluating Chinese medicine prescriptions. METHODS: Eighty-eight male Wistar rats were randomly divided into 4 groups. At d00, d42, d70, d98 (ni=20, 20, 24, 24) during fatty-feeding, rats in each group were further divided into 10 or 12 subgroups (ni=2), respectively. Lacunar stroke were replicated with the injection of thrombi which coagulated artificially from itself blood. The median lethal doses (LD50) were regressed from accumulative mortality in each geometric thrombus doses (k=0.75, 0.5, 0.85, 0.85), respectively. The degree of vascular dementia was evaluated as exploratory, learning and memorizing abilities. The median effective dose of thrombus for replicating rat model was regressed from dementia scores which were derived from the abilities. The linear correlation was regressed between the values of LD50 or effective dose (ED50) and the durations (days) of hypercholesterolemia. This model of vascular dementia was pathologically confirmed as the neural injuries from lacunar stroke in rats. RESULTS: The hypercholesterolemia was indicated as elevated total cholesterol, triglyeerides low-density lipoprotein cholesterol, and decreased high-density lipoprotein cholesterol. The values of LD50 with its 95% confidence intervals (CI) were 1525.0 (1361.0-1709.0), 584.3 (490.1-696.6), 168.7 (163.7-173.8), or 62.4 (59.5-65.4) mg/mL, at d00, d42, d70, and d98, respectively. There is a linear regression between the values of LD50 and the durations of hypercholesterolemia (y=-15.33x+1390.0, r=0.963, P<0.05). The values of ED50 with its 95% CI were 528.8 (340.5-821.4), 217.0 (20.84-2259.0), 96.3 (23.4-402.6), or 47.0 (43.7-50.6) mg/mL from dementia score, at d00, d42, d70, and d98, respectively. There is a linear regression between the values of ED50 and the durations of hypercholesterolemia (y=-4.992x+484.2, r=0.965, P<0.05). The neural injuries were demonstrated as neural degeneration and necrosis. CONCLUSIONS: For evaluating Chinese medicine, a model of vascular dementia in rats is set up with the lacunar stroke from self-thrombosis during hypercholesterolemia. This model from lacunar stroke is useful to investigate the pathogenesis and treatment of vascular dementia.

The synergistic anticancer effect of cisplatin combined with Oldenlandia diffusa in osteosarcoma MG-63 cell line in vitro.

BACKGROUND: Oldenlandia diffusa (OD) is a well-known traditional Chinese medicine, which is used to prevent and treat many disorders, especially cancers. However, its role in osteosarcoma has not been well understood. Here, we used OD and cisplatin individually and combined in osteosarcoma MG-63 cell to explore whether OD could induce cellular apoptosis and suppress the ability of proliferation and invasion of osteosarcoma MG-63 cell. METHODS: The changes of cellular shape were analyzed by optical microscopy. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay was used to analyze cell survival rate in vitro. Flow cytometry was performed to detect cell cycle and cell death. Scratch migration assay was used to evaluate cell migration and invasion. Western blot was performed to determine the expression levels of pro-apoptotic and anti-apoptotic protein. RESULTS: In this study, we found that the survival rate reduced significantly in the combined group compared with the individual group and control group. The apoptosis-inducing effect of combined application was much more significant than that of individual application. The invasion ability of combined application was significantly lower than that of the individual application. In the combined group, there were high expression levels of pro-apoptotic protein and low expression of anti-apoptotic protein. Cell-cycle analysis showed a change in the cell-cycle distribution and arrested cells in G2-M phase. CONCLUSION: In this study, we found that OD inhibited proliferation and induced apoptosis in the human osteosarcoma MG-63 cell line in a time-dependent and dose-dependent manner. In addition, OD displayed inhibitory activity on MG-63 cell proliferation and invasion and the study also showed that OD activity might be mediated by caspase activation. These data suggest that OD might represent a novel, efficient candidate agent for further experimentation in osteosarcoma treatment.