Apoptosis In MG-63 Cells Research Articles

Aucubin Induces Apoptotic Cell Death Through Caspase-dependent Pathways in Human Osteosarcoma MG-63 Cells

Background Osteosarcomas (OSs) are predominantly generated by mesenchymal cells, which commonly develop in the distal and upper regions of the bones. OS has high mortality rates and treatment failures, mostly due to the presence of lung metastases. Purpose The present work aimed to scrutinize the anticancer potentials of aucubin against OS human osteosarcoma (MG-63) cells. Methods The proliferation of the control and aucubin-treated MG-63 cells was studied by an XTT assay. Various fluorescent staining assays were done to assess the endogenous reactive oxygen species (ROS) accumulation and apoptosis in the aucubin-treated MG-63 cells. The caspase-3, -8, and -9 activities were investigated using the assay kits. Results The XTT assay results confirmed that the aucubin treatment considerably reduced the MG-63 cells. The findings of the various fluorescent staining assays evidenced that the aucubin treatment remarkably promoted endogenous ROS accumulation and apoptosis in the OS cells. The caspase activities were also improved in the OS cells after the aucubin treatment. Conclusion The results of this work show that aucubin treatments inhibit cell proliferation and trigger apoptosis in MG-63 cells, suggesting its potential as a promising anticancer agent. These findings will facilitate the future development of aucubin as a talented anticancer agent to treat OS.

LncRNA-PVT1 Inhibits Ferroptosis through Activating STAT3/GPX4 Axis to Promote Osteosarcoma Progression.

Osteosarcoma (OS) is a primary malignant bone tumor in the pediatric and adolescent populations. Long non-coding RNAs (LncRNAs), such as plasma-cytoma variant translocation 1 (PVT1), have emerged as significant regulators of OS metastasis. Recent studies have indicated that activation of signal transducer and activator of transcription 3 (STAT3) signaling, which might be controlled by PVT1, inhibits ferroptosis to promote the malignant progression of cancer. Therefore, the present study aimed to determine the role of PVT1 in OS pathogenesis and investigate whether PVT1 affects OS progression by regulating STAT3/GPX4 pathway-mediated ferroptosis. The human OS cell line MG63 were transfected with sh-PVT1 plasmid to inhibit PVT1 expression, with or without co-transfection with a STAT3 overexpression plasmid. The expression of PVT1 was determined by real-time quantitative polymerase chain reaction (RT-qPCR). The proliferation, migration, invasion, and apoptosis of MG63 cells were determined using the cell counting kit-8 (CCK8), Transwell assay, and flow cytometry. The levels of malondialdehyde (MDA), Fe2+, and glutathione (GSH) were determined by ELISA kits, whereas reactive oxygen species (ROS) level was determined by immunofluorescence. The protein expression levels of STAT3, p-STAT3, and glutathione peroxidase 4 (GPX4) were detected by western blot (WB). PVT1 expression was significantly increased in MG63 cells. When knocking down PVT1 with sh-PVT1 plasmid, the proliferation, migration, and invasion of MG63 cells were markedly inhibited, while the rate of apoptosis was upregulated. Further investigation revealed that MG63 cells with PVT1 knockdown exhibited elevated levels of MDA, Fe2+, and ROS. In addition, the inhibition of PVT1 expression resulted in decreased levels of GSH and inhibited expression of p-STAT3 and GPX4. When sh-PVT1 was co-transfected with STAT3 overexpression plasmid in MG63 cells, the increased levels of MDA, Fe2+, and ROS were downregulated, and the decreased expressions of GSH, p-STAT3, and GPX4 were upregulated. PVT1 promotes OS metastasis by activating the STAT3/GPX4 pathway to inhibit ferroptosis. Targeting PVT1 might be a novel therapeutic strategy for OS treatment.

Multifunctional rare earth oxide/MBG composite microspheres as a carrier for bone tumor treatment

With the development of advanced composites, biomaterials have brought the field of tissue engineering and regeneration into a new era. Among them, composites of inorganic nonmetallic materials and rare earth oxides have unique structures and biochemical properties and have attracted widespread interest. In this work, rare earth oxides (CeO2)/inorganic nonmetallic materials (mesoporous bioactive glass, MBG) composite microspheres (CeO2/MBGs) were synthesized by a sol-gel method, and the in vitro biological effect of CeO2/MBGs was systematically studied. The filling of CeO2/MBGs in irregular bone tumor defects not only promoted osteogenic mineralization in MG63 cells but also had significant antibacterial effects on E. coli and S. aureus. CeO2 enters the MBG network as a network modifier, while doxorubicin (DOX) is adsorbed into the mesoporous structure through electrostatic interactions, which endows CeO2/MBGs with excellent bioactivity and controlled DOX release behavior. Moreover, the results of in vitro experiments showed that the proper addition of rare earth oxides had no toxic effect on normal cells, and the combination of rare earth oxides with antitumor drugs could slow the release of DOX through the use of an intelligent response design system, thus inducing the apoptosis of MG63 cells. This work suggested that combination chemotherapy and the design of a rare earth oxide/MBG composite microspheres may be potential therapeutic approaches for the postoperative repair of bone tumor defects. The construction of this multifunctional rare earth oxide/inorganic biocomposite provides a way to apply the material to bone tissue.

Mefenamic acid exhibits antitumor activity against osteosarcoma by impeding cell growth and prompting apoptosis in human osteosarcoma cells and xenograft mice model

The study investigates the anticancer activity of mefenamic acid against osteosarcoma, shedding light on its underlying mechanisms and therapeutic potential. Mefenamic acid exhibited robust inhibitory effects on the proliferation of MG-63, HOS, and H2OS osteosarcoma cells in a dose-dependent manner. Moreover, mefenamic acid induced cellular toxicity in MG63 cells, as evidenced by LDH leakage, reflecting its cytotoxic impact. Furthermore, mefenamic acid effectively suppressed the migration and invasion of MG-63 cells. Mechanistically, mefenamic acid induced apoptosis in MG-63 cells through mitochondrial depolarization, activation of caspase-dependent pathways, and modulation of the Bcl-2/Bax axis. Additionally, mefenamic acid promoted autophagy and inhibited the PI3K/Akt/mTOR pathway, further contributing to its antitumor effects. The molecular docking studies provide compelling evidence that mefenamic acid interacts specifically and strongly with key proteins in the PI3K/AKT/mTOR pathway, suggesting a novel mechanism by which mefenamic acid could exert anti-osteosarcoma effects. In vivo studies using a xenograft mouse model demonstrated significant inhibition of MG-63 tumor growth without adverse effects, supporting the translational potential of mefenamic acid as a safe and effective therapeutic agent against osteosarcoma. Immunohistochemistry staining corroborated the in vivo findings, highlighting mefenamic acid's ability to suppress tumor proliferation and inhibit the PI3K/AKT/mTOR pathway within the tumor microenvironment. Collectively, these results underscore the promising therapeutic implications of mefenamic acid in combating osteosarcoma, warranting further investigation for clinical translation and development.

Effects of matrix viscoelasticity on cell-matrix interaction, actin cytoskeleton organization, and apoptosis of osteosarcoma MG-63 cells.

Many recent reports have shown the effects of viscoelasticity of the extracellular matrix on the spreading, migration, proliferation, survival and cell-matrix interaction of mesenchymal stem cells and normal cells. However, the effect of matrix viscoelasticity on the behavior of tumor cells is still in the state of preliminary exploration. To this aim, we prepared a viscoelastic hydrogel matrix with a storage modulus of about 2 kPa and a loss modulus adjustable from 0 to 600 Pa, through adding linear alginate and regulating the compactness of a polyacrylamide covalent network. Overall, the addition of viscous components inhibited the apoptosis of osteosarcoma MG-63 cells, while it promoted their spreading and proliferation and in particular led to a well-developed cytoskeleton organization. However, with the increase of the viscous fraction, this trend was reversed, and the apoptosis of MG-63 cells gradually increased with gradually decreased spreading and proliferation, accompanied by a surprising manner change of the cytoskeleton from fusiform cells dominated by focal adhesion to dendritic cells dominated by pseudopodia. Besides the upregulation of MAPK, Ras, Rap1 and PI3K-Akt pathways commonly involved in mechanotransduction, the upregulation of the Wnt pathway and inhibited endoplasmic reticulum stress-mediated apoptosis were observed for the viscous matrix with a low loss modulus. The high viscosity matrix showed additional involvement of Hippo and NF-kappa B signaling pathways related to the cell-matrix interaction, with downregulation of the endoplasmic reticulum stress pathway and upregulation related to mitochondrial organization. Our study would provide insight into the effect of viscosity on fundamental behaviors of tumor cells and might have important implications in designing antitumor materials.

Abalone shell-derived Mg-doped mesoporous hydroxyapatite microsphere drug delivery system loaded with icariin for inducing apoptosis of osteosarcoma cells.

Hydroxyapatite (HAP) porous microspheres with very high specific surface area and drug loading capacity, as well as excellent biocompatibility, have been widely used in tumour therapy. Mg2+ is considered to be a key factor in bone regeneration, acting as an active agent to stimulate bone and cartilage formation, and is effective in accelerating cell migration and promoting angiogenesis, which is essential for bone tissue repair, anti-cancer, and anti-infection. In this study, abalone shells from a variety of sources were used as raw materials, and Mg2+-doped abalone shell-derived mesoporous HAP microspheres (Mg-HAP) were prepared by hydrothermal synthesis as Mg2+/ icariin smart dual delivery system (ICA-Mg-HAP, IMHA). With increasing of Mg2+ doping, the surface morphology of HAP microspheres varied from collapsed macroporous to mesoporous to smooth and non-porous, which may be due to Mg2+ substitution or coordination in the HAP lattice. At 30% Mg2+ doping, the Mg-HAP microspheres showed a more homogeneous mesoporous morphology with a high specific surface area (186.06 m2/g). The IMHA microspheres showed high drug loading (7.69%) and encapsulation rate (83.29%), sustained Mg2+ release for more than 27 days, sustained and stable release of icariin for 60 hours, and good responsiveness to pH (pH 6.4 > pH 5.6). In addition, the IMHA delivery system stimulated the rapid proliferation of bone marrow mesenchymal stem cells and induced apoptosis in MG63 cells by blocking the G2 phase cycle of osteosarcoma cells and stimulating the high expression of apoptotic genes (Bcl-2, caspase-3, -8, -9). This suggests that the abalone shell-based IMHA may have potential applications in drug delivery and tumour therapy.

Assessment of anticancer properties of cumin seed (Cuminum cyminum) against bone cancer.

Early-life osteosarcoma is associated with severe morbidity and mortality, particularly affecting young children and adults. The present cancer treatment regimen is exceedingly costly, and medications like ifosfamide, doxorubicin, and cisplatin have unneeded negative effects on the body. With the introduction of hyphenated technology to create medications based on plant molecules, the application of ayurvedic medicine as a new dimension (formulation, active ingredients, and nanoparticles) in the modern period is rapidly growing. The primary source of lead compounds for the development of medications for avariety of ailments is plants and their products. Traditionally, Cuminum cyminum (cumin) has been used as medication to treat a variety of illnesses and conditions. The cumin seed was successfully extracted with solvents Hexane, Chloroform, Methanol, Ethanol and Acetone. Following the solvent extraction, the extract residue was assayed in MG63 cells for their anti-proliferative properties. First, we used the [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] (MTT) assay to test the extracted residue's cytotoxicity. The results show that hexane extract Half-maximal inhibitory concentration (IC50 86 µG/mL) effciently inhibits cells by causing programmed cell death. Furthermore, using the Acridine orange/ethidium bromide (AO/EB) staining method, the lactate dehydrogenase assay, and the reactive oxygen species assay using the Dichloro-dihydro-fluorescein diacetate (DCHFDA) staining method, we have demonstrated that the hexane extract causes apoptosis in MG63 cells. Furthermore, flow cytometry research revealed that the hexane extract stops the cell cycle in the S phase. In addition, the hexane extract limits colony formation and the migration potential as shown by the scratch wound healing assay. Furthermore, the extract from cumin seeds exhibits remarkable bactericidal properties against infections that are resistant to drugs. Gas chromatography analysis was used to quantitatively determine the hexane and methanolic extract based on the experimental data. The primary chemical components of the extract are revealed by the study, and these help the malignant cells heal. The present study finds that there is scientific validity in using cumin seeds as a novel method of anticancer therapy after undergoing both intrinsic and extrinsic research.

Pterostilbene-Isothiocyanate Inhibits Proliferation of Human MG-63 Osteosarcoma Cells via Abrogating β-Catenin/TCF-4 Interaction-A Mechanistic Insight.

Osteosarcoma, a highly metastasizing bone neoplasm, is a leading cause of death and disability in children and adolescents worldwide. Osteosarcoma is only suboptimally responsive to surgery and radio- and chemotherapy, that too with adverse side effects. Hence, there is a necessary need for safer alternative therapeutic approaches. This study evaluated the anticancer effects of the semi-synthetic compound, pterostilbene-isothiocyanate (PTER-ITC), on human osteosarcoma MG-63 cells through cytotoxicity, wound-healing, and transwell-migration assays. Results showed that PTER-ITC specifically inhibited the survival, proliferation, and migration of osteosarcoma cells. PTER-ITC induced apoptosis in MG-63 cells by disrupting mitochondrial membrane potential, as evident from the outcomes of different cytological staining. The antimetastatic potential of PTER-ITC was evaluated through immunostaining, RT-qPCR, and immunoblotting. In silico (molecular docking and dynamic simulation) and, subsequently, biochemical [co-immunoprecipitation (Co-IP) and luciferase reporter] assays deciphered the underlying mode-of-action of this compound. PTER-ITC increased E-cadherin and reduced N-cadherin levels, thereby facilitating the reversal of epithelial-mesenchymal transition (EMT). It also modulated the expressions of proliferative cell nuclear antigen (PCNA), caspase-3, poly [ADP-ribose] polymerase (PARP-1) and matrix metalloproteinase-2/9 (MMPs-2/9) at transcriptional and translational levels. PTER-ITC interfered with the β-catenin/transcription factor-4 (TCF-4) interaction in silico by occupying the β-catenin binding site on TCF-4, confirmed by their reduced physical interactions (Co-IP assay). This inhibited transcriptional activation of TCF-4 by β-catenin (as shown by luciferase reporter assay). In conclusion, PTER-ITC exhibited potent anticancer effects in vitro against human osteosarcoma cells by abrogating the β-catenin/TCF-4 interaction. Altogether, this study suggests that PTER-ITC may be regarded as a new approach for osteosarcoma treatment.

Matrix Stiffness Regulated Endoplasmic Reticulum Stress-mediated Apoptosis of Osteosarcoma Cell through Ras Signal Cascades.

The modulating effects of matrix stiffness on spreading and apoptosis of tumor cells have been well recognized. Nevertheless, the detail road map leading to the apoptosis and the underlying mechanisms governing the cell apoptosis have remained to be elucidated. To this aim, we provided a tunable elastic hydrogel matrix that promoted cell adhesion by modifying the surface of polyacrylamide with polydopamine, with stiffness value of 1, 10, 30, and 250 kPa, respectively. While the cell spreading increased and the apoptosis decreased with the matrix stiffness, such modulating effect of matrix on cell spreading exhibited different time evolvement behaviors as a function of stiffness, which likely led to surprisingly similar apoptosis rates for the 30 kPa and 250 kPa samples. Matrix stiffness mediated the spreading and apoptosis of MG-63 cells by regulating cell adhesion to matrix and in particular cytoskeletal organization, which was dependent on Ras, Rap1 and PI3K-Akt signaling pathways and finally led to the apoptosis of cancer cells dominated by endoplasmic reticulum stress pathway. Our results provided an insight into the regulation of tumor cell fate by the mechanical clues of ECM, which would have implication for future cancer research and the design of novel anticancer materials.

Paradox: Curcumin, a Natural Antioxidant, Suppresses Osteosarcoma Cells via Excessive Reactive Oxygen Species.

Osteosarcoma (OS) is an aggressive tumor with a rare incidence. Extended surgical resections are the prevalent treatment for OS, which may cause critical-size bone defects. These bone defects lead to dysfunction, weakening the post-surgical quality of patients' life. Hence, an ideal therapeutic agent for OS should simultaneously possess anti-cancer and bone repair capacities. Curcumin (CUR) has been reported in OS therapy and bone regeneration. However, it is not clear how CUR suppresses OS development. Conventionally, CUR is considered a natural antioxidant in line with its capacity to promote the nuclear translocation of a nuclear transcription factor, nuclear factor erythroid 2 (NRF2). After nuclear translocation, NRF2 can activate the transcription of some antioxidases, thereby circumventing excess reactive oxygen species (ROS) that are deleterious to cells. Intriguingly, this research demonstrated that, in vitro, 10 and 20 μM CUR increased the intracellular ROS in MG-63 cells, damaged cells' DNA, and finally caused apoptosis of MG-63 cells, although increased NRF2 protein level and the expression of NRF2-regulated antioxidase genes were identified in those two groups.

Schisandrin B Inhibits Osteosarcoma Cell Proliferation and Promotes Apoptosis Through PI3K/AKT/mTOR Pathway Mediated Autophagy

Osteosarcoma is the most common primary malignant bone tumor; the main treatment method is surgery and adjuvant chemotherapy, with a 5-year survival rate of less than 20% for metastatic patients. Schisandrin B is the most abundant and active ingredient found in the fruit of Schisandra chinensis (Turcz.) Baill., Schisandraceae, which has document properties such as liver protection, antioxidant, anti-inflammatory, antiaging, and antitumor. The present investigation explored the therapeutic effect of schisandrin B on osteosarcoma (MG63 cells). Cell proliferation and viability, scratch assay, and transwell migration analysis were used to detect the effects of schisandrin B on the growth activity, migration, and invasion of MG63 cells. The effects of schisandrin B on MG63 cell apoptosis were detected by flow cytometry and tunel staining. Western blot was used to detect the expression levels of autophagy and apoptosis related proteins. Immunofluorescence staining was used to detect schisandrin B effects of autophagy and apoptosis on MG63 cells. Schisandrin B inhibited the growth activity, migration ability, and invasion ability of osteosarcoma cells. In addition, schisandrin B induced apoptosis of MG63 cells through autophagy mediated by PI3K/AKT/mTOR signaling pathway.Graphical

Cell migration induces apoptosis in osteosarcoma cell via inhibition of Wnt-β-catenin signaling pathway

The current design scheme on anti-cancer materials is mainly through tuning the mechanical properties of the materials to induce apoptosis in cancer cells, with the involvement of Rho/ROCK signaling pathway. We hypothesize that tuning the motility is another potential important approach to modifying the tumor microenvironment and inducing tumor apoptosis. To this aim, we have prepared RGD-modified substrates to regulate cell motility through modification of RGD with different concentrations, and systematically examined the effect of motility on the apoptosis of tumor cells, and the potential involvement of Wnt signaling pathway. Our studies indicated that RGD modification could be readily used to tune the motility of cancer cells. High RGD concentration significantly suppressed the migration of cancer cells, leading to significantly increased apoptosis rate, about three times of that of the unmodified samples. Western-blot analysis also showed that cell with low motility expressed more caspase-3 and PARP proteins. Further RNA sequence study strongly suggested that low motility inhibited the canonical Wnt signaling pathway, which in turn led to the activation of the mitochondria-associated caspase signaling pathway, and ultimately to the apoptosis of osteosarcoma cells. Activation of the Wnt-β-catenin pathway through HLY78 significantly suppressed the apoptosis of MG-63 cells, further suggesting the critical role of Wnt pathway in motility-regulated-apoptosis of tumor cells. Our findings shed insights to understand the underlying mechanisms that induced the tumor cell apoptosis, and might provide new strategy for designing the novel anti-tumor materials.

Xianling Gubao attenuates high glucose-induced bone metabolism disorder in MG63 osteoblast-like cells.

Diabetes mellitus (DM) patients are prone to osteoporosis, and high glucose (HG) can affect bone metabolism. In the present study, we investigated the protective effects of traditional Chinese herbal formulation Xianling Gubao (XLGB) on HG-treated MG63 osteoblast-like cells. MG63 cells were incubated with control (mannitol), HG (20 mM glucose) or HG + XLGB (20 mM glucose+200 mg/L XLGB) mediums. Cell proliferation, apoptosis, migration and invasion were examined using CCK8, colony-formation, flow cytometry, Hoechst/PI staining, wound-healing and transwell assays, respectively. ELISA, RT-PCR and western blot analysis were used to detect the levels of osteogenesis differentiation-associated markers such as ALP, OCN, OPN, RUNX2, OPG, and OPGL in MG63 cells. The levels of the PI3K/Akt signaling pathway related proteins, cell cycle-related proteins, and mitochondrial apoptosis-related proteins were detected using western blot analysis. In HG-treated MG63 cells, XLGB significantly attenuated the suppression on the proliferation, migration and invasion of MG63 cells caused by HG. HG downregulated the activation of the PI3K/Akt signaling pathway and the expressions of cell cycle-related proteins, while XLGB reversed the inhibition of HG on MG63 cells. Moreover, XLGB significantly reduced the promotion on the apoptosis of MG63 cells induced by HG, the expressions of mitochondrial apoptosis-related proteins were suppressed by XLGB treatment. In addition, the expressions of osteogenesis differentiation-associated proteins were also rescued by XLGB in HG-treated MG63 cells. Our data suggest that XLGB rescues the MG63 osteoblasts against the effect of HG. The potential therapeutic mechanism of XLGB partially attributes to inhibiting the osteoblast apoptosis and promoting the bone formation of osteoblasts.

Caffeic Acid Induces Apoptosis in MG-63 Osteosarcoma Cells via Protein Kinase C Delta (PKCδ) Translocation and Mitochondrial Membrane Potential Reduction

BACKGROUND: Caffeic acid has been reported to activate caspases in MG-63 osteosarcoma cells, which can lead to apoptosis via both extrinsic and intrinsic apoptotic pathways. Translocation of protein kinase C delta (PKCδ), which reduces mitochondrial membrane potential (ΔΨm), is involved in apoptosis. The role of PKCδ translocation and ΔΨm alteration in caffeic acid-induced MG-63 cell apoptosis are largely unknown. Present study investigated the effect of caffeic acid on PKCδ translocation and ΔΨm in MG-63 cells.METHODS: MG-63 cells were cultured and starved, followed by pretreatment with or without Z-VAD-FMK and treatment with or without 10 μg/mL caffeic acid. MG-63 cells were collected, lysed, and processed to obtain cytosolic and mitochondrial fractions. Each fraction was subjected to immunoblotting analysis by using anti-PKCδ antibody. Mitochondrial membrane potential (ΔΨm) was measured using flow cytometry.RESULTS: Cytosolic PKCδ levels were higher than mitochondrial PKCδ levels in untreated and 1 h caffeic acid treatment groups. Inversely, cytosolic PKCδ levels were lower than the mitochondrial PKCδ levels after 6 and 12 h caffeic acid treatment. By Z-VAD-FMK pretreatment, cytosolic PKCδ levels were higher than mitochondrial PKCδ after 6 and 12 h caffeic acid treatment. After 6 h treatment with caffeic acid, ΔΨm was slightly shifted. More shifting occurred in MG-63 cells treated with caffeic acid for 12 h. The ΔΨm shifting was inhibited by Z-VAD-FMK pretreatment.CONCLUSION: Caffeic acid could trigger apoptosis of MG-63 osteosarcoma cells by inducing PKCδ translocation to mitochondria and reducing ΔΨm, which might cause MMP.KEYWORDS: caffeic acid, MG-63, osteosarcoma, PKCδ, mitochondrial membrane potential, mitochondrial membrane permeabilization, Z-VAD-FMK

Investigating the Role of Quercetin in Increasing the Rate of Cisplatin-Induced Apoptosis Via the NF-κB Pathway in MG-63 Cancer Cells.

Numerous studies suggest that the co-treatment of chemotherapeutic agents with flavonoids such as Quercetin (Que) may enhance tumor cells' susceptibility to these agents. Hence, in the current study, we investigated Que's role in combination with Cisplatin to promote cell apoptosis by focusing on the NF-κB signaling pathway in the osteosarcoma cell lines. The Que, Cisplatin, and their combination's general cytotoxicity effects were evaluated using an MTT assay for 72 hrs. The protein expression levels of NF-κB were detected by an enzyme-linked immunosorbent assay (ELISA) Kit. Flow cytometry was used to evaluate cell apoptosis. Que considerably elevated the cytotoxicity of Cisplatin (P<0.05). Que also dramatically down-regulated the expression levels of NF-κB in MG-63 cells compared to mono-treatment (P<0.05). Besides, Que promotes cisplatin-induced apoptosis in MG-63 cells. Our study's findings provide an exact point in the field of adjuvant therapy in osteosarcoma. In other words, this study could provide new insights into a better understanding of the role of Que in elevating cisplatin-induced apoptosis with NF-κB down-regulation.

Polydopamine-modified ZIF-8 nanoparticles as a drug carrier for combined chemo-photothermal osteosarcoma therapy

Single chemotherapy often causes severe adverse effects and chemoresistance which limits therapeutic efficacy. Recently, combination of chemotherapy with photothermal therapy (PTT) have received broad attention for synergistic treatment of osteosarcoma, ultimately resulting in the enhancement of therapeutic efficacy of anticancer drugs. In this study, we have developed a novel drug delivery system based on polydopamine (pDA)-modified ZIF-8 nanoparticles loaded with methotrexate (MTX) (pDA/MTX@ZIF-8 NPs). Herein, pDA modification avoided the explosive release of the drug, and improved the biocompatibility and near-infrared (NIR) light absorbance performance of nanoparticles. The as-prepared pDA/MTX@ZIF-8 NPs could be used as drug targeting delivery system and simultaneously displayed excellent photothermal effects under NIR irradiation. Biology assays in vitro indicated that the pDA/MTX@ZIF-8 NPs were able to efficiently induce MG63 cell apoptosis through reducing mitochondrial membrane potentials (MMPs), and the introduction of photothermal agents enhanced the antitumor effect and decreased the dose of chemotherapeutic drugs. Moreover, the optimized pDA/MTX@ZIF-8 NPs (40 μg/mL) exhibited better photothermal conversion performance and facilitated tumor cells death. These results triumphantly exhibit that the pDA/MTX@ZIF-8 NPs have a synergistic effect of chemo-photothermal therapy (combination index CI = 0.346) and excellent biocompatibility, which has unexceptionable prospects for the therapy of osteosarcoma.

Construction of tellurium-doped mesoporous bioactive glass nanoparticles for bone cancer therapy by promoting ROS-mediated apoptosis and antibacterial activity

The commonly used treatment methods for bone cancer include chemotherapy, surgery and radiotherapy, but there are disadvantages such as nonspecific distribution, high toxicity of chemotherapy drugs, implantable infections and low monitoring. Nanoparticles are the new development direction of nanomedicine in cancer treatment. Structural characteristics of nanoparticles make it an excellent model for targeting and penetrating cancer-induced abnormal cell growth. In this study, a kind of novel and interesting tellurium ion doped mesoporous bioactive glasses (Te-MBG) nanoparticles were successfully synthesized by a simple sol–gel method, which had uniform spherical morphology (≈ 500 nm), high surface area (> 300 m2/g) and mesopore volume (> 0.30 cm3/g). Results found that Te doping does not affect the mineralization and degradation of the MBG nanoparticles. Meanwhile, compared to the undoped MBG, Te doped MBG not merely had the ability to promote MG63 cell apoptosis to inhibit bone cancer growth by ROS-mediated, but also had significant antibacterial activity. This all depends on the concentration of Te doping. It can be seen that Te-MBG nanoparticles can not only potentially fill bone defects caused by bone cancer removal, but also induce cancer cell apoptosis by tellurium release inducing reactive oxygen species (ROS) excessive production to inhibit bone cancer formation. This study provides a feasible strategy for the development of Te-MBG nanoparticles as well as their evaluation and basic research for bone cancer therapy.

Severe cellular stress activates apoptosis independently of p53 in osteosarcoma

Apoptosis induced by doxorubicin, bortezomib, or paclitaxel, targeting DNA, 26S proteasome, and microtubules respectively, was assessed in two osteosarcoma cells, p53 wild-type U2OS and p53-null MG63 cells. Doxorubicin-induced apoptosis only occurred in U2OS, not in MG63. In contrast, bortezomib and paclitaxel could drive U2OS or MG63 toward apoptosis effectively, suggesting that apoptosis induced by bortezomib or paclitaxel is p53-independent. The expressions of Bcl2 family members such as Bcl2, Bcl-xl, and Puma could be seen in U2OS and MG63 cells with or without doxorubicin, bortezomib, or paclitaxel treatment. In contrast, another member, Bim, only could be observed in U2OS, not in MG63, under the same conditions. Bim knockdown did not affect the doxorubicin-induced apoptosis in U2OS, suggested that a BH3-only protein other than Bim might participate in apoptosis induced by doxorubicin. Using a BH3-mimetic, ABT-263, to inhibit Bcl2 or Bcl-xl produced a limited apoptotic response in U2OS and MG63 cells, suggesting that this BH3-mimetic cannot activate the Bax/Bak pathway efficiently. Significantly, ABT-263 enhanced doxorubicin- and bortezomib-induced apoptosis synergistically in U2OS and MG63 cells. These results implied that the severe cellular stress caused by doxorubicin or bortezomib might be mediated through a dual process to control apoptosis. Respectively, doxorubicin or bortezomib activates a BH3-only protein in one way and corresponding unknown factors in another way to affect mitochondrial outer membrane permeability, resulting in apoptosis. The combination of doxorubicin with ABT-263 could produce synergistic apoptosis in MG63 cells, which lack p53, suggesting that p53 has no role in doxorubicin-induced apoptosis in osteosarcoma. In addition, ABT-263 enhanced paclitaxel to induce moderate levels of apoptosis.

Enterococcus faecalis OG1RF induces apoptosis in MG63 cells via caspase-3/-8/-9 without activation of caspase-1/GSDMD.

Regulated cell death is key in the pathogenesis of persistent apical periodontitis. Here, we investigated the mechanisms of regulated cell death in osteoblast-like MG63 cells infected with Enterococcus faecalis OG1RF. MG63 cells were infected with live E.faecalis OG1RF at the indicated multiplicity of infection for the indicated infection time. We evaluated the cells by flow cytometry, terminal deoxynucleotidyl transferase dUTP nick end labelling assay and lactate dehydrogenase release analysis; measured the activity of caspase-1/-3/-8/-9 and the release of interleukin-1β; and determined the expression of apoptosis-associated proteins and gasdermin D by apoptosis antibody array and Western blotting. Enterococcus faecalis OG1RF reduced the mitochondrial membrane potential of the infected cells, increased the percentage of apoptotic and terminal deoxynucleotidyl transferase dUTP nick end labelling-positive cells, and enhanced lactate dehydrogenase release. The expression of caspase-3 and survivin and the activity of caspase-3/-8/-9 were upregulated, while the expression of death receptor 6 was downregulated. The activity of caspase-1/gasdermin D and the release of interleukin-1β remained unaltered. Enterococcus faecalis OG1RF induced both intrinsic and extrinsic MG63 cell apoptosis via caspase-3/-8/-9 activation but did not activate the pyroptotic pathway regulated by caspase-1/gasdermin D.

Engineering PDA-coated CM-CS nanoparticles for photothermo-chemotherapy of osteosarcoma and bone regeneration

After an osteosarcoma excision, recurrence and bone defects are significant challenges for clinicians. Combination therapy based on a nanoparticle-based drug delivery system shows great promise in osteosarcoma therapy. In this study, we designed a multifunctional chitosan (CS) nanoparticle, which combined photothermal therapy (PTT) with chemotherapy to synergistically enhance osteosarcoma therapy and bone repair. Curcumin (CM) loaded CS nanoparticles were prepared through ionotropic gelation method and were further functionalized with polydopamine (PDA) coating to form CS-CM-PDA nanoparticles (CCPNPs). The CCPNPs displayed pH- and near-infrared (NIR)- responsive CM release behavior. In vitro anti-cancer results indicated that CCPNPs possessed a long-term stable anti-cancer effect compared to pure CM. The presence of the NIR irradiation combined with CCPNPs resulted in a dramatic decrease in MG-63 osteosarcoma cell viability in 10 min compared with the pure CCPNPs at the concentration of 500 μg/mL. Meanwhile, in vitro study demonstrated that CCPNPs induced MG-63 cell apoptosis via downregulating the expression of Bcl-2 and upregulating the expression levels of Bax and Caspase-3. Besides, CCPNPs could positively induce the proliferation of MC3T3-E1 osteoblast cells in vitro. These results suggested that CCPNPs with bifunctional osteosarcoma therapy and bone repair may be an excellent candidate for local cancer therapy and bone regeneration.