Involvement of MMP-2 in adriamycin resistance dependent on ERK1/2 signal pathway in human osteosarcoma MG-63 cells

Matrix Metalloproteinases in Chemoresistance: Regulatory Roles, Molecular Interactions, and Potential Inhibitors

Cancer is one of the major causes of death worldwide. Its treatments usually fail when the tumor has become malignant and metastasized. Metastasis is a key source of cancer recurrence, which often leads to resistance towards chemotherapeutic agents. Hence, most cancer-related deaths are linked to the occurrence of chemoresistance. Although chemoresistance can emerge through a multitude of mechanisms, chemoresistance and metastasis share a similar pathway, which is an epithelial-to-mesenchymal transition (EMT). Matrix metalloproteinases (MMPs), a class of zinc and calcium-chelated enzymes, are found to be key players in driving cancer migration and metastasis through EMT induction. The aim of this review is to discuss the regulatory roles and associated molecular mechanisms of specific MMPs in regulating chemoresistance, particularly EMT initiation and resistance to apoptosis. A brief presentation on their potential diagnostic and prognostic values was also deciphered. It also aimed to describe existing MMP inhibitors and the potential of utilizing other strategies to inhibit MMPs to reduce chemoresistance, such as upstream inhibition of MMP expressions and MMP-responsive nanomaterials to deliver drugs as well as epigenetic regulations. Hence, manipulation of MMP expression can be a powerful tool to aid in treating patients with chemo-resistant cancers. However, much still needs to be done to bring the solution from bench to bedside.

Isoimperatorin Induces Apoptosis of Nasopharyngeal Carcinoma Cells via the MAPK/ERK1/2 Signaling Pathway

Objective

To investigate the effect of isoimperatorin on nasopharyngeal carcinoma CNE2 cell apoptosis and the role of the MAPK/ERK1/2 signaling pathway in inducing apoptosis.

Methods

Real-time cellular analysis technology (RTCA) and MTT were used to detect cell proliferation; Annexin V-FITC/PI dual-fluorescence flow cytometry analysis, Hoechst 33342 staining, and mitochondrial membrane potential detection kit were used to detect cell apoptosis; western blot was used to detect protein expression.

Results

Different concentrations of isoimperatorin (10 μM, 20 μM, 20 μM, 20 μM, 20 μM, 20 μM, 20 μM, 20 

Conclusion

Isoimperatorin can induce nasopharyngeal carcinoma CNE2 cell apoptosis through the MAPK/ERK1/2 signaling pathway.

Baicalein inhibits cell development, metastasis and EMT and induces apoptosis by regulating ERK signaling pathway in osteosarcoma

Background: Osteosarcoma is a highly malignant primary tumor. Baicalein has broad-spectrum anti-tumor effects. This study aimed to study the specific molecular regulatory mechanism of baicalein in anti-osteosarcoma and the possible regulatory signaling network involved.Methods: In vitro experiment, MG-63 cells treated with 0, 50, 75, and 100 μM of baicalein. Cell viability, proliferation, migration, invasion, cycle, apoptosis, and morphology were detected using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazoliumbromide (MTT), clone formation, wound healing, Transwell, flow cytometry, Hoechst staining, wound healing and microscopic observation. In addition, cycle, apoptosis and EMT-related proteins and p-ERK/ERK expression level were analyzed using western blotting. In vivo experiments were performed by BALB/c-nude mice model establishment to detect mice and tumor weight, tumor volume, positive rate and p-ERK/ERK expression when mice treated with 100 μM of baicalein.Results: Firstly, the IC₅₀ of baicalein was 67.57 μM. Then, baicalein decreased cell viability, proliferation, migration, invasion, and the expression of CDK2, Cyclin D1, Cyclin E1, Bcl-2, N-cad, Vimentin, MMP-2, MMP-9, p-ERK/ERK, while increased G1 phase numbers, apoptosis and the expression level of p21, p27, cleaved caspase 3/9, Bax, E-cad, ZO-1 in a dose-dependent manner in MG-63 cells. Also, baicalein reduced the body weight, tumor weight and volume and relative expression level of p-ERK/ERK in vivo.Conclusion: Baicalein inhibits cell development, metastasis, and EMT progress and induces cell cycle arrest and apoptosis by regulating ERK signaling pathway in osteosarcoma, and has a visible anti-osteosarcoma effect in vivo.

Ursolic acid suppresses the biological function of osteosarcoma cells

Osteosarcoma is a highly malignant tumour that occurs in adolescents. Upregulation or the constitutive activation of epidermal growth factor receptor (EGFR) is a hallmark of osteosarcoma. To investigate the effect of ursolic acid on the biological function of osteosarcoma, MTT assay was used to detect the effect of ursolic acid on the proliferation of HOS and MG63 cells, while flow cytometry was used to analyse the effect on the cell cycle and apoptosis. Transwell and Matrigel assays were used to detect the effect of ursolic acid on cell migration and invasion, respectively. Western blot analysis and reverse transcription-quantitative polymerase chain reaction were used to detect the effects of different concentrations of ursolic acid on EGFR signaling pathway-related proteins, cell cycle, apoptosis and cell migration-related proteins. After overexpression or silencing of EGFR, the effects of ursolic acid on EGFR pathway and cell biological function were subsequently detected, using the same methods. The present study identified that ursolic acid had inhibitory effects on the growth and metastatic ability of osteosarcoma cells by suppressing EGFR.

Bispecific antibody suppresses osteosarcoma aggressiveness through regulation of NF-κB signaling pathway

Osteosarcoma is one of the most lethal malignancies, and the prognosis remains dismal due to the paucity of effective therapeutic targets. Bmi-1 and TRIM-14 are associated with the initiation and progression of osteosarcoma, which could promote angiogenesis, invasion, and apoptotic resistance in bone cancer tissue. In this study, we constructed a bispecific antibody of BsAbBmi/TRIM targeting Bmi-1 and TRIM-14 and investigated the therapeutic value in bone carcinoma cells and xenograft mice. Our results showed that Bmi-1 and TRIM-14 expression levels were markedly upregulated correlated with nuclear factor-κB nuclear translocation in bone cancer cells and clinical carcinoma tissues. Results have demonstrated that overexpression of Bmi-1 and TRIM-14 promoted growth, proliferation, aggressiveness, and apoptosis resistance of osteosarcoma cells. BsAbBmi/TRIM administration significantly inhibited nuclear factor-κB expression derived by matrix metalloproteinase-9 promoter. BsAbBmi/TRIM administration inhibited growth of osteosarcoma cells and downregulated Bmi-1 and TRIM-14 expression levels. Data also demonstrated that migration and invasion of osteosarcoma cells were also inhibited by BsAbBmi/TRIM. In addition, results illustrated that BsAbBmi/TRIM inhibited tumor growth and tumorigenicity by blockaded sensor expression in nuclear factor-κB signal pathway. Furthermore, in vivo study showed that BsAbBmi/TRIM treatment markedly inhibited the tumorigenicity and growth of osteosarcoma cells compared to either AbBmi-1 or AbTRIM-14 treatment. Notably, survival of xenograft mice was prolonged by BsAbBmi/TRIM treatment compared to either AbBmi-1 or AbTRIM-14 treatment. In conclusion, these results provided new evidence that BsAbBmi/TRIM inhibited the progression of osteosarcoma, which suggest that BsAbBmi/TRIM may be a novel anti-cancer agent for osteosarcoma therapy.

Establishment and analysis of osteosarcoma cell sublines with different metastatic characteristics

The aim of this study is to establish human osteosarcoma MG-63 cell sublines with different metastatic characteristics and provide good experimental models for mechanism study of osteosarcoma metastasis. Six cell sublines were screened and established by using the in vitro cloning technology. In vitro invasion experiments, cellular electrophoretic mobility determinations, cellular proliferation rate determinations, and soft agar clone formation assays were used to compare, analyze, and identify the metastatic characteristics of various cell sublines. The results indicated that the invasion capacity, cellular electrophoretic mobility, cell proliferation, and soft agar clone formation capacity of A2, A3, and A16 sublines were higher than those of A1, A6, and A20 sublines. There was no significant difference in various values determined among A2, A3, and A16, and among A1, A6, and A20 (P > 0.05), but there were significant differences in various values determined between the former three and the latter three (P < 0.05). In conclusion, MG-63 cell sublines with different metastatic characteristics can be established by combining several technologies and can contribute to further research on the mechanism of osteosarcoma metastasis.