Norcantharidin inhibits proliferation and promotes apoptosis via c-Met/Akt/mTOR pathway in human osteosarcoma cells

Solute carrier family 35 member A2 regulates mitophagy through the PI3K/AKT/mTOR axis, promoting the proliferation, migration, and invasion of osteosarcoma cells

The treatment of osteosarcoma patients exhibits individual variability, underscoring the critical importance of targeted therapy. Although (Solute carrier family 35 member A2) SLC35A2's role in the progression of various cancers has been extensively investigated, its specific implications in osteosarcoma remain unexplored. Leveraging data from the (The Cancer Genome Atlas) TCGA and (Genotype-Tissue Expression) GTEx databases, we have discerned that SLC35A2 is notably upregulated in osteosarcoma and correlates with the prognosis of osteosarcoma patients. Consequently, it becomes imperative to delve into the role of SLC35A2 in the context of osteosarcoma. Our research substantiates that SLC35A2 exerts a notable influence on mitochondrial autophagy in osteosarcoma, thereby exerting cascading effects on the proliferation, migration, invasion, and apoptosis of osteosarcoma cells. Mechanistically, SLC35A2 orchestrates mitochondrial autophagy via the PI3K/AKT/mTOR signaling pathway. Moreover, we have conducted rigorous animal experiments to further corroborate the repercussions of SLC35A2 on osteosarcoma growth. In summation, our study elucidates that SLC35A2's modulation of mitochondrial autophagy through the PI3K/AKT/mTOR signaling pathway constitutes a pivotal factor in the malignant progression of osteosarcoma, unveiling promising therapeutic targets for patients grappling with this condition.

Soy isoflavones induces mitophagy to inhibit the progression of osteosarcoma by blocking the AKT/mTOR signaling pathway

BACKGROUND

Soy isoflavones (SI) is a natural bioactive substance exhibiting beneficial effects on human health. This study aims to elucidate the therapeutic potential of SI in the treatment of osteosarcoma (OS) and to investigate the underlying mechanisms, particularly focusing on mitophagy.

METHODS

The effects of SI on the proliferation, apoptosis, migration, and invasion of U2OS cells were analyzed. Mitophagy was assessed through multiple parameters: mitochondrial autophagosomes, mitochondrial membrane potential, autophagy-related proteins, reactive oxygen species (ROS), and oxygen consumption rate (OCR). Protein levels related to apoptosis, autophagy, and the AKT/mTOR pathway were analyzed using western blot. The therapeutic efficacy of SI was further identified using a mouse tumor xenograft model. Cell apoptosis and proliferation in tumor xenografts were detected by TUNEL staining and immunohistochemistry (IHC), respectively.

RESULTS

SI dose-dependently suppressed the viability, colony formation, migration, and invasion of U2OS cells, and enhanced the apoptosis. SI also dose-dependently induced mitophagy in OS cells, evidenced by an increase in autophagosomes and ROS levels, a decrease in mitochondrial membrane potential and OCR, and concomitant changes in autophagy-related proteins. Mdivi-1, an inhibitor of mitophagy, reversed the anti-tumor effects of SI on U2OS cells. In addition, SI blocked the AKT/mTOR pathway in U2OS cells. SC-79, an AKT agonist, reversed the effect of SI on inducing mitophagy. Moreover, SI also promoted cell apoptosis and mitophagy in tumor xenografts in vivo.

CONCLUSIONS

SI induces mitophagy in OS cells by blocking the AKT/mTOR pathway, contributing to the inhibition of OS.

Intratumoral injection of norcantharidin liposome emulsion hybrid delivery system amplifies the cancer-fighting effects of oral sorafenib against hepatocellular carcinoma

Interventional therapies are increasingly used in clinical trials for hepatocellular carcinoma (HCC). Sorafenib is the front-line remedy for HCC, however, chemoresistance occurs immutably and affects the effectiveness of treatment. In a previous study, a norcantharidin liposome emulsion hybrid (NLEH) delivery system for HCC was developed. This study aims to examine the therapeutic effects of the combination of intratumoral injection of NLEH and sorafenib in treating HCC. Sorafenib combined with NLEH activated the apoptosis pathway by synergistically upregulating caspase-9, promoting cytotoxicity, apoptosis (64.57%), and G2/M cell cycle arrest (48.96%). Norcantharidin could alleviate sorafenib resistance by counteracting sorafenib-induced phosphorylation of Akt. Additionally, intratumoral injection of NLEH exhibited a sustained accumulation in the tumor within 24 h and didn't distribute to other major organs. Intratumoral injection of NLEH in combination with oral sorafenib displayed the most potent tumor growth inhibitory effect (77.91%) in vivo. H&E staining results and the indicators of the renal and liver function tests demonstrated the safety of this combination therapy. Overall, these results showed that intratumoral injection of NLEH in combination with oral sorafenib treatment represented a rational potential therapeutic option for HCC.

Evaluation of anti-cancer effects of carnosine and melittin-loaded niosomes in MCF-7 and MDA-MB-231 breast cancer cells

Background: We investigated the anti-cancer effect of carnosine-loaded niosomes (Car-NIO) and melittin-loaded niosomes (Mel-NIO) with olaparib in breast cancer cell lines (MCF-7 and MDA-MB-231). Methods: The thin film method was used for preparing the niosomes and characterized in terms of morphology, size, and polydispersity index (PDI). We further evaluated the impact of these peptides on breast cancer cells viability, RT-qPCR assays, malondialdehyde (MDA) activity, and cell cycle progression, to determine if these are linked to carnosine and melittin's anti-proliferative properties. Results: Car-NIO and Mel-NIO in vitro study inhibited cancer cell viability. They have also upregulated the expression of protein 53 (P53), BCL2-Associated X Protein (Bax), caspase-9, caspase-3, programmed cell death 4 (PDCD4), and Forkhead box O3 (FOXO3), while downregulated the expression of B-cell lymphoma 2 (Bcl2), poly (ADP-ribose) polymerase (PARP 1), and MicroRNA-183 (miRNA-183). The MCF-7 cells were arrested at the G2/M phase in Car-NIO, on the other hand, the MDA-MB-231 cells were arrested at the S phase. While the Mel-NIO and olaparib arrested the MCF-7 and MDA-MB-231 cells at the G0/1 phase. Conclusion: Our study successfully declared that Mel-NIO had more anti-cancer effects than Car-NIO in both MCF-7 and MDA-MB-231 breast cancer cells.

Functional anti-bone tumor biomaterial scaffold: construction and application

Bone tumors, including primary bone tumors and bone metastases, have been plagued by poor prognosis for decades. Although most tumor tissue is removed, clinicians are still confronted with the dilemma of eliminating residual cancer cells and regenerating defective bone tissue after surgery. Therefore, functional biomaterial scaffolds are considered to be the ideal candidates to bridge defective tissues and restrain cancer recurrence. Through functionalized structural modifications or coupled therapeutic agents, they provide sufficient mechanical strength and osteoinductive effects while eliminating cancer cells. Numerous novel approaches such as photodynamic, photothermal, drug-conjugated, and immune adjuvant-assisted therapies have exhibited remarkable efficacy against tumors while exhibiting low immunogenicity. This review summarizes the progress of research on biomaterial scaffolds based on different functionalization strategies in bone tumors. We also discuss the feasibility and advantages of the combined application of multiple functionalization strategies. Finally, potential obstacles to the clinical translation of anti-tumor bone bioscaffolds are highlighted. This review will provide valuable references for future advanced biomaterial scaffold design and clinical bone tumor therapy.

Norcantharidin Nanoemulsion Development, Characterization, and In Vitro Antiproliferation Effect on B16F1 Melanoma Cells

Melanoma is a highly lethal type of cancer that has had an increase in incidence in the last decades. Nevertheless, current therapies lack effectiveness and have highly disabling side effects, which calls for new therapeutic strategies. Norcantharidin (NCTD) is an acid derivative with potential antitumor activity isolated from natural blister beetles. However, its solubility limitations restrict its use. To address this issue, we developed an oil-in-water nanoemulsion using commonly available cosmetic ingredients, which increased NCTD solubility 10-fold compared to water. The developed nanoemulsion showed a good droplet size and homogeneity, with adequate pH and viscosity for skin application. In vitro drug release studies showed a sustained release profile, ideal for prolonged therapeutic effects. Accelerated stability studies proved that the formulation was reasonably stable under stress conditions, with particle separation fingerprints, instability index, particle size, and sedimentation velocity analyses being conducted. To assess the therapeutic potential of the developed formulation, in vitro studies were conducted on melanoma B16F1 cells; results showed an IC50 of 1.026 +/− 0.370 mg/kg, and the cells’ metabolic activity decreased after exposure to the NCTD nanoemulsion. Hence, a new “easy-to-make” nanoformulation with therapeutic potential on melanoma cells was developed, as a possible adjuvant for future melanoma treatment.

Supramolecular self-assembled AIE molecules are used in the search for target proteins in norcantharidin

Norcantharidin (NCTD), a demethylated derivative of cantharidin, is an anticancer active component in traditional Chinese medicine. At present, the main methods for finding its target proteins are pharmacological methods and biophysical screening, which cannot achieve the purpose of efficient and accurate screening. Here we established a new analytical method for specific fishing and assisted imaging for norcantharidin target proteins. For the AIE supramolecule probe, the benzophenone azide (BPA) fluorescent nanoparticles with strong AIE properties were encapsulated in biocompatible DSPE-PEG that covalently coupled with NCTD (named BPA@NCTD NPs). The target proteins of NCTD can be captured by BPA@NCTD NPs, and then be detected to investigate the potential signaling pathways. The screened differential proteins were analysed through the protein and signaling pathway database, and multiple signaling pathways were obtained and verified. The mechanism of norcantharidin in inhibiting the migration and invasion of A549 cells through the P53 signaling pathway was confirmed by Western blot experiments. Our research showed that AIE supramolecule probe BPA@NCTD NPs has the dual functions of specific screening of A549 cells target proteins and biological imaging, which not only offers a good anti-fluorescence quenching ability for the dynamic imaging process of NCTD, but also provides a novel and efficient specific method for efficient analysis of target proteins and signal pathways.

Norcantharidin toxicity profile: an in vivo murine study

Norcantharidin (NCTD) is the demethylated analog of cantharidin, with allegedly reduced toxicity. However, there is still limited information regarding its posology and potential risk in its use in cancer treatment. Healthy BDF1 mice were intraperitoneally administered with norcantharidin (0, 3, 6, 12, and 25 mg/kg) every 24 h for 6 days. Survivor mice were euthanized, and the brain, lungs, kidneys, spleen, and liver were procured for enzymatic and histopathological analysis in the liver and kidney. DL₅₀ were 8.86 mg/kg for females and 11.77 mg/kg for males. The treatments with 3.0 mg/kg and 6.0 mg/kg significantly modified the phosphorylase, alanine transaminase, and γ-glutamyl transferase activities; however, an organ-specific response was detected. A significant dose-dependent decrease was observed in the kidney for ROS, while the liver had the opposite effect. Histopathological analysis revealed a significant elevation in hepatocytes' nuclei average size and total area (3 mg/kg), as well as centrilobular vein and adjacent sinusoidal capillaries showed a significant difference. The portal triad presented a significant difference in veins and capillarity count in 6 mg/kg. Renal samples showed cortex convoluted tubules' average size significantly augmented in both doses' groups, and tubule count was found augmented in 6 mg/kg. These physiological effects of NCTD can be exploited as treatment strategies if able to operate in an established posology and proper testing.

Norcantharidin down-regulates iron contents in the liver and spleen of lipopolysaccharide-treated mice

Objective

The inhibiting effect of Norcantharidin (NCTD) on IL-6 (interleukin-6) and STAT3 and the involvement of the IL-6/STAT3 pathway in hepcidin expression prompted us to speculate that NCTD could affect iron metabolism.

Methods

We examined the effects of NCTD on serum iron (SI) and transferrin (Tf) saturation, iron and ferritin light chain (FTL), transferrin receptor 1 (TfR1), divalent metal transporter 1 (DMT1), ferroportin 1 (Fpn1), iron regulatory protein 1 (IRP1) and hepcidin, as well as IL-6 and STAT3 in the liver, spleen and duodenum of mice treated with lipopolysaccharide (LPS) in vivo, using RT-PCR, Western blotting and immunofluorescence analysis.

Results

NCTD could increase SI and Tf saturation and reduce tissue iron and FTL content by affecting expression of cell-iron transport proteins TfR1, DMT1 and Fpn1. The impact of NCTD on TfR1, DMT1 and Fpn1 expression is mediated by up-regulating IRP1 and down-regulating hepcidin expression, while NCTD-induced down-regulation of hepcidin is mediated by the IL-6/STAT3 signalling pathway in LPS-treated mice.

Conclusions

NCTD affects iron metabolism by modifying the expression of IL-6/JAK2/STAT3/hepcidin and IRP1 and suggest that the ability of NCTD to reduce tissue iron contents may be a novel mechanism associated with the anti-cancer effects of NCTD.

Mitophagy—A New Target of Bone Disease

Bone diseases are usually caused by abnormal metabolism and death of cells in bones, including osteoblasts, osteoclasts, osteocytes, chondrocytes, and bone marrow mesenchymal stem cells. Mitochondrial dysfunction, as an important cause of abnormal cell metabolism, is widely involved in the occurrence and progression of multiple bone diseases, including osteoarthritis, intervertebral disc degeneration, osteoporosis, and osteosarcoma. As selective mitochondrial autophagy for damaged or dysfunctional mitochondria, mitophagy is closely related to mitochondrial quality control and homeostasis. Accumulating evidence suggests that mitophagy plays an important regulatory role in bone disease, indicating that regulating the level of mitophagy may be a new strategy for bone-related diseases. Therefore, by reviewing the relevant literature in recent years, this paper reviews the potential mechanism of mitophagy in bone-related diseases, including osteoarthritis, intervertebral disc degeneration, osteoporosis, and osteosarcoma, to provide a theoretical basis for the related research of mitophagy in bone diseases.

Norcantharidin induces ferroptosis via the suppression of NRF2/HO‑1 signaling in ovarian cancer cells

Increasing evidence has indicated a crucial role of ferroptosis in ovarian cancer (OC). Norcantharidin (NCTD), a normethyl compound of cantharidin, is extensively used in clinical practice as an optional anticancer drug. However, whether NCTD leads to ferroptosis in OC has not been previously explored, at least to the best of our knowledge. In the present study, the effect of NCTD on SKOV3 and OVCAR-3 cells was evaluated. The experimental data of the present study revealed that NCTD significantly suppressed SKOV3 and OVCAR-3 cell viability in a concentration- and time-dependent manner. The results of Cell Counting Kit-8 assay revealed that NCTD treatment decreased SKOV3 and OVCAR-3 cell viability. In comparison, pre-incubation with ferrostatin-1 (Fer-1) significantly reversed the NCTD-induced reduction in SKOV3 and OVCAR-3 cell viability; however, no changes in cell viability were observed when the SKOV3 and OVCAR-3 cells were treated with NCTD, in combination with the apoptosis inhibitor, Z-VAD-FMK, the ferroptosis inhibitor, necrostatin-1, and the autophagy inhibitor, 3-methyladenine. Additionally, it was observed that NCTD markedly enhanced reactive oxygen species production and malondialdehyde and ferrous ion levels in the SKOV3 and OVCAR-3 cells; however, pre-incubation with Fer-1 abolished these effects. Flow cytometry also demonstrated a significant increase in cell death following treatment of the SKOV3 and OVCAR-3 cells with NCTD; however, pre-incubation with Fer-1 also reversed these effects. In vivo experiments demonstrated that NCTD significantly reduced tumor volume and weight. More importantly, it was revealed that nuclear factor erythroid 2-related factor 2 (NRF2), heme oxygenase 1 (HO-1), glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (xCT) expression levels were significantly decreased following NCTD treatment. Collectively, NCTD may represent a potent anticancer agent in OC cells, and NCTD-induced ferroptotic cell death may be achieved by inhibiting the NRF2/HO-1/GPX4/xCT axis.

Norcantharidin ameliorates the development of murine lupus via inhibiting the generation of IL-17 producing cells

Systemic lupus erythematosus (SLE) is a devastating autoimmune disorder associated with severe organ damage. The abnormality of T cell apoptosis is considered as an important pathogenetic mechanism of SLE. Norcantharidin (NCTD), a derivative of Cantharidin, is an efficacious anti-cancer drug by inhibiting cell proliferation and inducing cell apoptosis. Besides, NCTD has also been proved to protect the function of kidneys, while damaged renal function is the most important predictor of morbidity and mortality in SLE. All these suggest the potential effects of NCTD in SLE treatment. In this study we investigated whether NCTD exerted therapeutic effects in a mouse SLE model. Lupus prone female MRL/lpr mice were treated with NCTD (1, 2 mg·kg^-1·d^-1, ip) for 8 weeks. We showed that NCTD administration significantly decreased mortality rate, diminished the expression of anti-dsDNA IgG antibody, a diagnostic marker for SLE, as well as restored renal structure and function in MRL/lpr mice. Moreover, NCTD administration dose-dependently inhibited lymphoproliferation and T cell accumulation in the spleens of MRL/lpr mice. We further revealed that NCTD specifically inhibited DN T cell proliferation and Th17 cell differentiation both via blocking activation of signal transducer and activator of transcription 3 (STAT3) signaling pathway. On the other hand, NCTD did not affect T cell apoptosis in MRL/lpr mice. Taken together, our data suggest that NCTD may be as a promising therapeutic drug through targeting T cells for the treatment of SLE.

Norcantharidin Induces Immunogenic Cell Death of Bladder Cancer Cells through Promoting Autophagy in Acidic Culture

The acidic tumor microenvironment stands as a major obstacle to the efficient elimination of tumor cells. Norcantharidin (NCTD) is a powerful antitumor agent with multiple bioactivities. However, the effect of NCTD under acidic conditions is still unclear. Here, we report that NCTD can efficiently kill bladder cancer (BC) cells in acidic culture, and more intriguingly, NCTD can induce immunogenic cell death (ICD), thereby promoting antitumor immunity. In NCTD-treated BC cells, the surface-exposed calreticulin (ecto-CALR) was significantly increased. Consistently, co-culture with these cells promoted dendritic cell (DC) maturation. The NCTD-induced ICD is autophagy dependent, as autophagy inhibition completely blocked the NCTD-induced ecto-CALR and DC maturation. In addition, the DC showed a distinct maturation phenotype (CD80^high CD86^low) in acidic culture, as compared to that in physiological pH (CD⁸⁰ high CD86^high). Finally, the NCTD-induced ICD was validated in a mouse model. NCTD treatment significantly increased the tumor-infiltrating T lymphocytes in MB49 bladder cancer mice. Immunizing mice with NCTD-treated MB49 cells significantly increased tumor-free survival as compared to control. These findings demonstrate that NCTD could induce ICD in an acidic environment and suggest the feasibility to combine NCTD with anticancer immunotherapy to treat BC.

Norcantharidin combined with paclitaxel induces endoplasmic reticulum stress mediated apoptotic effect in prostate cancer cells by targeting SIRT7 expression

Prostate cancer (PCa), an extremely common malignancy in males, is the most prevalent disease in several countries. Norcantharidin (NCTD) has antiproliferation, antimetastasis, apoptosis, and autophagy effects in various tumor cells. Nevertheless, the antitumor effect of NCTD combined with paclitaxel (PTX), a chemotherapeutic drug, in PCa remains unknown. The cell growth, proliferative rate, cell cycle distribution, and cell death were determined by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide, colony formation assay, PI staining, and Annexin V/PI staining by flow cytomertry, whereas the mitochondrial membrane potential (MMP) and endoplasmic reticulum (ER) stress was evaluated using the MitoPotential assay and ER-ID red assay. We also evaluated the protein and mRNA expression of SIRTs by Western blotting and qRTPCR assay. Overexpression effectivity was measured by DNA transfection assay. Our study showed that cell viability and proliferative PC3 and DU145 rates were effectively inhibited after NCTD-PTX combination. We also found that NCTD-PTX combination treatment significantly enhance G2/M phase arrest, induction of cell death and ER stress, loss of MMP, and ER- or apoptotic-related protein expression. Furthermore, NCTD-PTX combination treatment was significantly decreasing the protein and mRNA expression of SIRT7 in PCa cells. Combination therapy effectively reduced cell viability, ER stress-mediated apoptosis and p-eIF2α/ATF4/CHOP/cleaved-PARP expression inhibition in SIRT7 overexpression of PCa cells. These results indicate that NCTD combined with PTX induces ER stress-mediated apoptosis of PCa cells by regulating the SIRT7 expression axis. Moreover, combination therapy may become a potential therapeutic strategy against human PCa.

Establishment of an Autophagy-Related Clinical Prognosis Model for Predicting the Overall Survival of Osteosarcoma

Purpose

Osteosarcoma is the most common primary and highly invasive bone tumor in children and adolescents. The purpose of this study is to construct a multi-gene expression feature related to autophagy, which can be used to predict the prognosis of patients with osteosarcoma. Materials and methods. The clinical and gene expression data of patients with osteosarcoma were obtained from the target database. Enrichment analysis of autophagy-related genes related to overall survival (OS-related ARGs) screened by univariate Cox regression was used to determine OS-related ARGs function and signal pathway. In addition, the selected OS-related ARGs were incorporated into multivariate Cox regression to construct prognostic signature for the overall survival (OS) of osteosarcoma. Use the dataset obtained from the GEO database to verify the signature. Besides, gene set enrichment analysis (GSEA) were applied to further elucidate the molecular mechanisms. Finally, the nomogram is established by combining the risk signature with the clinical characteristics.

Results

Our study eventually included 85 patients. Survival analysis showed that patients with low riskScore had better OS. In addition, 16 genes were included in OS-related ARGs. We also generate a prognosis signature based on two OS-related ARGs. The signature can significantly divide patients into low-risk groups and high-risk groups, and has been verified in the data set of GEO. Subsequently, the riskScore, primary tumor site and metastasis status were identified as independent prognostic factors for OS and a nomogram were generated. The C-index of nomogram is 0.789 (95% CI: 0.703~0.875), ROC curve and calibration chart shows that nomogram has a good consistency between prediction and observation of patients.

Conclusions

ARGs was related to the prognosis of osteosarcoma and can be used as a biomarker of prognosis in patients with osteosarcoma. Nomogram can be used to predict OS of patients and improve treatment strategies.

Norcantharidin-blocked ANXA2P2 inhibits fibroblast proliferation by increasing UBAP2L mRNA stability through LIN28B

AIMS

Norcantharidin (NCTD) exhibits antitumor, anti-inflammatory, and anti-fibrosis properties, which makes NCTD an attractive candidate for the treatment of pathological scars. This study was designed to investigate the potential effects of NCTD on fibroblast proliferation and explore the underlying mechanisms.

MATERIALS AND METHODS

First, cell viability and cell apoptosis were evaluated to determine the effects of NCTD on human skin fibroblasts, at 10, 50, and 100 μM. To explore the mechanism, bioinformatics analyses, chromatin immunoprecipitation, RNA immunoprecipitation, and RNA pulldown assays, and luciferase reporter assays were performed to verify the relationships among NCTD, signal transducer and activator of transcription 3 (STAT3), annexin A2 pseudogene 2 (ANXA2P2), and ubiquitin-associated protein 2-like (UBAP2L) mRNA in fibroblasts. Loss-of-function experiments were performed to investigate the roles played by STAT3, ANXA2P2, and UBAP2L in the proliferation and apoptosis of fibroblasts.

KEY FINDINGS

We found that NCTD administration induced fibroblast apoptosis and inhibited fibroblast proliferation in a dose-dependent manner. Mechanistically, NCTD inhibited ANXA2P2 transcription through the inhibition of STAT3 phosphorylation. Subsequently, ANXA2P2 was found to enhance the physical interaction between UBAP2L mRNA and lin-28 homolog B (LIN28B), which increased the stability and levels of UBAP2L mRNA. Loss-of-function assays demonstrated that ANXA2P2 and UBAP2L knockdown induced fibroblast apoptosis and suppressed fibroblast proliferation.

SIGNIFICANCE

In conclusion, we confirmed that NCTD inhibits fibroblast proliferation by inhibiting the STAT3/ANXA2P2/UBAP2L axis, which suggested that NCTD could represent a new candidate for the treatment of pathological scars.

Compound TDB (Tricyclic decyl benzoxazole) induces autophagy-dependent apoptosis in the gastric cancer cell line MGC-803 by regulating PI3K/AKT/mTOR

OBJECTIVE

Gastric cancer is a potential malignant tumor. Extensive research has shown that apoptosis and autophagy are important mechanisms of cancer pathogenesis. This study aimed to explore the role and mechanism of TDB in apoptosis and autophagy in MGC-803 cells.

METHODS

In cell experiments, the proliferation, apoptosis and autophagy of MGC-803 cells were evaluated by the MTT assay, TUNEL, flow cytometry, MDC, and TEM. Through molecular experiments, the TDB-induced apoptosis and autophagy effects were evaluated by examining the levels of Cleaved-PARP/PARP, Cleaved-caspase3/procaspase3, Beclin-1, p62 and the ratio of LC3-II/LC3-I. At the animal level, the anti-tumor effect of TDB in vivo was evaluated by assessing tumor volume and bioluminescence value.

RESULTS

Regarding mechanism, TDB induces apoptosis and autophagy through PI3K/AKT/mTOR. At the same time, more importantly, TDB promotes 3-methyladenine or autophagy activator rapamycin-mediated. The induced proliferation inhibition and pro-apoptosis effect, which inhibit autophagy and induce an increase in apoptosis.

CONCLUSION

TDB may up-regulate PARP, Cleaved Caspase-3, Beclin1 and LC3B and down-regulate the expression of P62 and other apoptosis and autophagy genes through the activation of PI3K/AKT/mTOR pathway signalling proteins, leading to autophagy-dependent apoptosis. At the animal level, TDB has good anti-tumor efficacy in vivo. In summary, TDB has potential anti-tumor efficacy in vivo and in vitro.

Antitumor potential of the protein phosphatase inhibitor, cantharidin, and selected derivatives

Cantharidin is a potent natural protein phosphatase monoterpene anhydride inhibitor secreted by several species of blister beetle, with its demethylated anhydride analogue, (S)-palasonin, occurring as a constituent of the higher plant Butea frondosa. Cantharidin shows both potent protein phosphatase inhibitory and cancer cell cytotoxic activities, but possible preclinical development of this anhydride has been limited thus far by its toxicity. Thus, several synthetic derivatives of cantharidin have been prepared, of which some compounds exhibit improved antitumor potential and may have use as lead compounds. In the present review, the potential antitumor activity, structure-activity relationships, and development of cantharidin-based anticancer drug conjugates are summarized, with protein phosphatase-related and other types of mechanisms of action discussed. Protein phosphatases play a key role in the tumor microenvironment, and thus described herein is also the potential for developing new tumor microenvironment-targeted cancer chemotherapeutic agents, based on cantharidin and its naturally occurring analogues and synthetic derivatives.

Norcantharidin protects against renal interstitial fibrosis by suppressing TWEAK-mediated Smad3 phosphorylation

AIMS

This study investigated the role and mechanism of action of tumor necrosis factor-like weak inducer of apoptosis (TWEAK) in the pathogenesis of renal interstitial fibrosis (RIF), and its involvement in the anti-RIF effect of norcantharidin (NCTD).

MAIN METHODS

Mice with unilateral ureteral obstruction and BUMPT mouse proximal tubular cells exposed to transforming growth factor (TGF)-β1 were used as in vivo and in vitro models of RIF, respectively. NCTD was administered to mice by intraperitoneal injection (0.075 mg kg^-1·day^-1). Hematoxylin-eosin and Masson's trichrome staining were performed to assess pathologic changes in the kidney. Immunohistochemistry, western blotting, and real-time PCR were performed to evaluate the expression of TWEAK and the fibrotic factors fibronectin (FN) and collagen type I (Col-I). The role of TWEAK in RIF and in the anti-RIF effect of NCTD was evaluated by TWEAK overexpression and neutralization with a specific antibody, and specific inhibitor of Mothers against decapentaplegic homolog (Smad)3 (SIS3) was used to examine the involvement of TGF-β1/Smad3 signaling.

KEY FINDINGS

TWEAK was mainly expressed in renal tubules in mice; the level was markedly elevated in both in vivo and in vitro RIF models. TWEAK overexpression in BUMPT cells increased the levels of phosphorylated Smad3, FN, and Col-I, which were reduced by treatment with SIS3. NCTD suppressed FN and Col-I expression by blocking TWEAK-mediated Smad3 phosphorylation.

SIGNIFICANCE

Upregulation of TWEAK contributes to RIF by promoting Smad3 phosphorylation, while NCTD inhibits this process.

Norcantharidin: research advances in pharmaceutical activities and derivatives in recent years

Cantharidin (CTD) is the main bioactive component of Cantharides, which is called Banmao in Traditional Chinese Medicine (TCM). Norcantharidin (NCTD) is a structural modifier of CTD. To compare with CTD, NCTD has lighter side effects and stronger bioactivity in anti-cancer through inhibiting cell proliferation, causing apoptosis and autophagy, overwhelming migration and metastasis, affecting immunity as well as lymphangiogenesis. Examples of these effects include suppressing Protein Phosphatase 2A and modulating Wnt/beta catenin signal, with Caspase family proteins, AMPK pathway and c-Met/EGFR pathway involving respectively. Moreover, NCTD has the effects of immune enhancement, anti-platelet aggregation and inhibition of renal interstitial fibrosis with distinct signaling pathways. The immunological effects induced by NCTD are related to the regulation of macrophage polarization and LPS-mediated immune response. The antiplatelet activity that NCTD induced is relevant to the inhibition of platelet signaling and the downregulation of α2 integrin. Furthermore, some of novel derivatives designed and synthesized artificially show stronger biological activities (e.g., anticancer effect, enzyme inhibition effect, antioxidant effect) and lower toxicity than NCTD itself. Plenty of literatures have reported various pharmacological effects of NCTD, particularly the anticancer effect, which has been widely concerned in clinical application and laboratory research. In this review, the pharmaceutical activities and derivatives of NCTD are discussed, which can be reference for further study.

Insight into norcantharidin, a small-molecule synthetic compound with potential multi-target anticancer activities

Norcantharidin (NCTD) is a demethylated derivative of cantharidin, which is an anticancer active ingredient of traditional Chinese medicine, and is currently used clinically as a routine anti-cancer drug in China. Clarifying the anticancer effect and molecular mechanism of NCTD is critical for its clinical application. Here, we summarized the physiological, chemical, pharmacokinetic characteristics and clinical applications of NCTD. Besides, we mainly focus on its potential multi-target anticancer activities and underlying mechanisms, and discuss the problems existing in clinical application and scientific research of NCTD, so as to provide a potential anticancer therapeutic agent for human malignant tumors.

Knockdown of KRT17 decreases osteosarcoma cell proliferation and the Warburg effect via the AKT/mTOR/HIF1α pathway

Keratins are fibrous structural proteins that serve essential roles in forming the stratum corneum and protect the cells in this layer of skin from damage. Keratin 17 (KRT17) is a key member of the keratins, and dysregulated expression of KRT17 has been reported in various types of cancer, such as lung and gastric cancer. The present study aimed to identify the role of KRT17 in osteosarcoma and the underlying molecular mechanism. The expression of KRT17 in osteosarcoma tissues and cell lines was detected using reverse transcription‑quantitative PCR (RT‑qPCR) and western blotting. The effects of KRT17 on osteosarcoma cell proliferation and the Warburg effect in vitro were detected using CCK‑8 and colony formation assays, cell cycle distribution analysis and metabolic measures. The effects of KRT17 on osteosarcoma cell proliferation in vivo were detected using a subcutaneous tumorigenesis model. The association between KRT17 and the AKT/mTOR/hypoxia‑inducible factor 1α (HIF1α) pathway was detected using RT‑qPCR and western blotting. The results demonstrated that KRT17 was highly expressed in osteosarcoma tissues and cell lines. Knockdown of KRT17 decreased osteosarcoma cell proliferation and colony formation, induced G1 phase arrest and inhibited glycolysis in vitro. Similarly, the suppression of KRT17 decreased osteosarcoma tumor growth in vivo. Knockdown of KRT17 decreased the expression of phosphorylated (p)‑AKT, p‑mTOR, HIF1α and the target gene of HIF1α glucose transporter 1. Restoring the expression of p‑AKT, p‑mTOR or HIF1α reversed the effect of KRT17 inhibition on cell proliferation and glycolysis. These results indicated that knockdown of KRT17 may be an effective method for treating osteosarcoma through inhibiting osteosarcoma cell proliferation and the Warburg effect by suppressing the AKT/mTOR/HIF1α pathway.

Cantharidic acid induces apoptosis in human nasopharyngeal carcinoma cells through p38-mediated upregulation of caspase activation

Cantharidic acid (CA) is the hydrolysis product of the acid anhydride cantharidin, which is a natural toxin secreted by several species of blister beetles. Several studies have indicated that as an inhibitor of protein phosphatase 2 (PP2A), CA induces apoptosis in various human cancer cells. However, the effect of CA on human nasopharyngeal carcinoma (NPC) cells and the underlying pathways have not been addressed. In our current study, we tested the hypothesis that CA treatment reduces the viability of human NPC cells (HONE-1, NPC-39, and NPC-BM) by inducing apoptosis. Results indicated that CA markedly reduced cell viability, which was revealed by the upregulation of caspase activation in extrinsic and intrinsic apoptosis pathways as well as the upregulation of extracellular-signal-regulated kinase 1/2 (ERK1/2), p38, and c-Jun N-terminal kinase 1/2 (JNK1/2) pathways. Coadministration of a p38 inhibitor (SB203580) with CA abolished the activation of caspase proteins. These findings indicated that CA treatment leads to apoptosis in human NPC cells through the upregulation of caspase activation, mediated particularly by the p38 pathway. Hence, CA is a promising therapeutic agent for human NPC.

FAM64A Promotes Osteosarcoma Cell Growth and Metastasis and Is Mediated by miR-493

Aberrant expression of FAM64A was correlated with cell proliferation in various cancer types. We examined the expression of FAM64A and the upstream gene miR-493 in OS. The functions of miR-493 were revealed through extensive experiments. We found an increase of FAM64A gene and protein in OS tissues. Overexpression of FAM64A resulted in promoting tumor proliferation, migration, and invasion. The miR-493 targeted and negatively regulated FAM64A. Our data showed that upregulation of FAM64A in OS correlated with poor prognosis.

Strontium/Chitosan/Hydroxyapatite/Norcantharidin Composite That Inhibits Osteosarcoma and Promotes Osteogenesis In Vitro

Hydroxyapatite can deliver drugs, and its composite material is capable of repairing bone defects in tumors. This study was conducted to evaluate the effect of composite materials on tumor growth inhibition and bone growth induction. Composites containing drug delivery compounds were synthesized by coprecipitation and freeze-drying and then characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). In addition, the effect of hydroxyapatite nanoparticles (nano-SHAP) on proliferation of an osteosarcoma cell line (MG-63) and an osteoblast cell line (MC3T3-E1) was evaluated, and its mechanism was studied. The use of nano-SHAP alone did not affect the proliferation of normal cell lines. However, nanoparticles containing different amounts of norcantharidin in the composite materials and had different inhibitory effects on osteosarcoma and different effects on osteoblasts. And, with the increase of the content of norcantharidin, the antitumor performance of the composite has been enhanced. In summary, the nano-SHAP system developed in this study is a drug delivery material that can inhibit the growth of tumors and induce the proliferation of osteoblasts.

Norcantharidin inhibits proliferation and promotes apoptosis via c-Met/Akt/mTOR pathway in human osteosarcoma cells

Osteosarcoma (OS) is the most common malignant bone tumor and frequently affects adolescents. Norcantharidin (NCTD), a demethylated derivative of cantharidin, has been reported to exhibit anticancer activity against various types of tumors but not human OS. The aim of the present study was to evaluate the effects of NCTD on OS cell lines (MG63 and HOS) and to explore the underlying mechanisms. In the present study, the proliferation of OS cells decreased significantly, while the apoptosis was accelerated significantly after exposure to NCTD. Meanwhile, our results also indicated that NCTD could suppress the migration and invasion, decrease the colony‐forming ability and induce S phase cell cycle arrest of OS cells in a dose‐dependent manner. Moreover, our results revealed that the anticancer effects induced by NCTD on OS cells involved autophagy, mitophagy, endoplasmic reticulum stress and c‐Met pathway. Furthermore, the results of animal experiments showed that NCTD inhibited tumor growth in a xenograft model of human OS. These results provide important new insight into the possible molecular mechanisms of NCTD and highlight its potential use as an antitumor drug for human OS.