MiR-506 exerts antineoplastic effects on osteosarcoma cells via inhibition of the Skp2 oncoprotein

LncRNA HOXA-AS3 promotes cell proliferation and invasion via targeting miR-218-5p/FOXP1 axis in osteosarcoma

Osteosarcoma is an aggressive form of bone cancer and affects the health in children and adolescents. Although conventional treatment improves the osteosarcoma survival, some patients have metastasis and drug resistance, leading to a worse prognosis. Therefore, it is necessary to explore the molecular mechanism of osteosarcoma occurrence and progression, which could discover the novel treatment for osteosarcoma. Long noncoding RNAs (lncRNAs) have been reported to regulate osteosarcoma occurrence and malignant progression. LncRNA HOXA-AS3 facilitates the tumorigenesis and progression in a variety of human cancers. However, the underlying mechanism of lncRNA HOXA-AS3-induced oncogenesis is poorly determined in osteosarcoma. To address this point, we utilized several cellular biological strategies and molecular approaches to explore the biological functions and mechanisms of lncRNA HOXA-AS3 in osteosarcoma cells. We found that lncRNA HOXA-AS3 facilitates cell proliferation and invasion via targeting miR-218-5p/FOXP1 axis in osteosarcoma. In conclusion, lncRNA HOXA-AS3 could be a promising target for osteosarcoma treatment.

Targeting the untargetable: RB1-deficient tumours are vulnerable to Skp2 ubiquitin ligase inhibition

Proteins that regulate the cell cycle are accumulated and degraded in a coordinated manner during the transition from one cell cycle phase to the next. The rapid loss of a critical protein, for example, to allow the cell to move from G1/G0 to S phase, is often regulated by its ubiquitination and subsequent proteasomal degradation. Protein ubiquitination is mediated by a series of three ligases, of which the E3 ligases provide the specificity for a particular protein substrate. One such E3 ligase is SCF^Skp1/Cks1, which has a substrate recruiting subunit called S-phase kinase-associated protein 2 (Skp2). Skp2 regulates cell proliferation, apoptosis, and differentiation, can act as an oncogene, and is overexpressed in human cancer. A primary target of Skp2 is the cyclin-dependent kinase inhibitor p27 (CDKN1b) that regulates the cell cycle at several points. The RB1 tumour suppressor gene regulates Skp2 activity by two mechanisms: by controlling its mRNA expression, and by an effect on Skp2's enzymatic activity. For the latter, the RB1 protein (pRb) directly binds to the substrate-binding site on Skp2, preventing protein substrates from being ubiquitinated and degraded. Inactivating mutations in RB1 are common in human cancer, becoming more frequent in aggressive, metastatic, and drug-resistant tumours. Hence, RB1 mutation leads to the loss of pRb, an unrestrained increase in Skp2 activity, the unregulated decrease in p27, and the loss of cell cycle control. Because RB1 mutations lead to the loss of a functional protein, its direct targeting is not possible. This perspective will discuss evidence validating Skp2 as a therapeutic target in RB1-deficient cancer.

Efficacy of ifosfamide combined with liposome doxorubicin on osteosarcoma and its effects on serum IL-10, TNF-α, and IFN-γ in patients with osteosarcoma

OBJECTIVE

To evaluate the effects of ifosfamide combined with liposome doxorubicin on osteosarcoma (OS) and its effects on serum IL-10, TNF-α, and IFN-γ in patients with OS.

METHODS

A total of 86 patients with OS who received chemotherapy in Honghui Hospital, Xi'an Jiaotong University from Jan. 2017 to Dec. 2019 were enrolled. Patients treated by conventional doxorubicin + ifosfamide were assigned to the regular group (n=40). Others treated by liposome doxorubicin + ifosfamide were assigned to the research group (n=46). The clinical efficacy, 2-year survival rate, and adverse reactions of the two groups were evaluated and compared. ELISA was adopted for quantification of tumor specific growth factor (TSGF), vascular endothelial growth factor (VEGF), erb-b2 receptor tyrosine kinase 3 (ERBB3), tumor necrosis factor-α (TNF-α), interferon-gamma-γ (IFN-γ), and interleukin-10 (IL-10). The EORTC Quality of Life Questionnaire (QLQ-C30) was adopted to evaluate a patient's life quality.

RESULTS

The research group showed a higher total effective rate and a higher 2-year survival rate than the regular group, but lower incidences of liver and kidney function injury, thrombocytopenia, and cardiotoxicity than the regular group. After therapy, lower levels of serum TSGF, VEGF, ERBB3, and TNF-α were found in the research group than those in the regular group. Higher levels of IFN-γ and IL-10 were found in the former than those in the latter. The research group got higher scores of QLQ-C30 than the regular group.

CONCLUSION

Liposome doxorubicin + ifosfamide can improve the clinical efficacy on patients with OS and improve their recovery and life quality.

SKP2 regulates ZEB1 expression and stimulates eutopic endometrial stromal cell invasion and proliferation of adenomyosis

Though endometriosis is benign, however, it shares certain characteristics with cancers, such as the ability to invade and metastasize. Previous studies have demonstrated that S-phase kinase associated protein2 (SKP2) promotes invasion, tumorigenesis, and metastasis. However, its correlation with adenomyosis is unclear. Herein, we aimed to look into SKP2 expression patterns and regulatory effects on endometrial stromal cell (ESC) proliferation and invasion, and its internal mechanism in adenomyosis. Western blot, qRT-PCR, and immunochemistry were carried out for detecting SKP2 and ZEB1 expression in ESC of adenomyosis and adenomyosis endometrial tissue. The primary ESCs were identified using immunofluorescence. SKP2 knockdown was accomplished in vitro by transfecting a particular lentivirus vector. The colony formation and CCK-8 assays were carried out for assessing cell proliferation, while cell invasion potential was assessed using the transwell assay. Both SKP2 and ZEB1 were found to be significantly upregulated in adenomyosis endometrial tissue. Knockdown of SKP2 inhibited adenomyotic ESC invasion and proliferation. Further experiments showed that knocking out SKP2 reduced ZEB1 expression in adenomyotic ESCs. Our results showed that SKP2 could regulate ZEB1 expression, and increased SKP2 may play a role in the pathogenesis of adenomyosis and stimulating ESC proliferation and invasion.