MicroRNA-21 Inhibits the Apoptosis of Osteosarcoma Cell Line SAOS-2 via Targeting Caspase 8

Curcumin and its Analogs and Carriers: Potential Therapeutic Strategies for Human Osteosarcoma

Curcumin is a natural polyphenol phytochemical derived from turmeric with antioxidant, anti-inflammatory, and anticancer properties but is concerned about poor solubility in water, absorption, and metabolic stability. Potent metastatic osteosarcoma is the most common primary bone cancer in children, adolescents, and young adults. It is responsible for low survival rates because of its high rate of metastasis to the lungs. To improve poor bioavailability, numerous curcumin analogs were developed to possess anticancer characteristics through a variety of biological pathways involved in cytotoxicity, proliferation, autophagy, sensitizing chemotherapy, and metastases. This review provides an overview of their various pharmacological functions, molecular mechanisms, and therapeutic potential as a remedy for human osteosarcoma. To enhance therapeutic efficacy, several liposomal nanoparticles, nanocarriers, multifunctional micelles, and three-dimensional printed scaffolds have also been developed for the controlled delivery of curcumin targeting human osteosarcoma cells. Consequently, curcumin and several potential analogs and delivery formulations are optimistic candidates to improve the currently available strategy for human osteosarcoma. However, further insight into the mechanism of action of promising curcumin analogs and the development of carriers in clinical trials of osteosarcoma needs to be investigated to improve their overall potency and clinical utility, in particular the anti-metastatic effect.

Lipid Nanoparticles and Liposomes for Bone Diseases Treatment

Because of their outstanding biocompatibility, sufficient capacity to control drug release, and passive targeting capability, lipid nanoparticles are one of the world's most widely utilized drug delivery systems. However, numerous disadvantages limit the use of lipid nanoparticles in clinical settings, especially in bone regeneration, such as challenges in transporting, storing, and maintaining drug concentration in the local area. Scaffolds are frequently employed as implants to provide mechanical support to the damaged area or as diagnostic and imaging tools. On the other hand, unmodified scaffolds have limited powers in fostering tissue regeneration and curing illnesses. Liposomes offer a solid foundation for the long-term development of various commercial solutions for the effective drug delivery-assisted treatment of medical conditions. As drug delivery vehicles in medicine, adjuvants in vaccination, signal enhancers/carriers in medical diagnostics and analytical biochemistry, solubilizers for various ingredients as well as support matrices for various ingredients, and penetration enhancers in cosmetics are just a few of the industrial applications for liposomes. This review introduces and discusses the use of lipid nanoparticles and liposomes and the application of lipid nanoparticles and liposome systems based on different active substances in bone diseases.

Possible Role of lncRNA MEG3-microRNA-21 and Endoplasmic Reticulum (ER) Stress Proteins in the Pathogenesis of Psoriasis Vulgaris

BACKGROUND

Psoriasis is a chronic inflammatory immune mediated disease arising from interaction between genetic risk variants and the environment. Maternally expressed gene3 (MEG3) is a long noncoding RNA (lncRNA) known for gene transcription regulation and inhibiting proliferation. MEG3 competes with microRNA (miRNA-21) influencing cell proliferation and apoptosis balance. Endoplasmic reticulum (ER) stress proteins promote cell survival via unfolded protein response (UPR) influenced by MEG3. We aimed to detect the possible role of MEG3, miRNA-21 and ER stress proteins in pathogenesis of psoriasis vulgaris.

METHODS

Human GRP78, ATF6, caspase3 tissue levels were assayed by Enzyme Linked Immunosorbent Assay (ELISA). Assessment of long non-coding MEG3 and miRNA 21 expressions was done by quantitative real time polymerase chain reaction (qRT-PCR).

RESULTS

Expression of MEG3 was significantly downregulated, while miRNA-21 was remarkably upregulated, ER stress proteins GRP78, ATF6, and caspase 3 all showed low levels in homogenized psoriatic lesions when compared to normal skin. miRNA 21 and MEG3 were identified as possible diagnostic markers for psoriasis vulgaris.

DISCUSSION

MEG3 is barely expressed in psoriatic lesions while miRNA-21 expression is remarkably elevated but when correlated to each other there was unexpected positive correlation. MEG3 and miRNA-21 were identified as possible diagnostic markers for psoriasis. Undifferentiated psoriatic lesions have very weak UPR.

Cancer-Derived Extracellular Vesicles: Their Role in Sarcoma

Soft tissue sarcomas (STS) are rare malignancies with limited responses to anticancer therapy. Extracellular vesicles (EVs) are a heterogeneous group of bi-lipid layer sacs secreted by cells into extracellular space. Investigations of tumor-derived EVs have revealed their functional capabilities, including cell-to-cell communication and their impact on tumorigenesis, progression, and metastasis; however information on the roles of EVs in sarcoma is currently limited. In this review we investigate the role of various EV cargos in sarcoma and the mechanisms by which those cargos can affect the recipient cell phenotype and the aggressivity of the tumor itself. The study of EVs in sarcoma may help establish novel therapeutic approaches that target specific sarcoma subtypes or biologies, thereby improving sarcoma therapeutics in the future.

Research Progress of Exosome-Loaded miRNA in Osteosarcoma

Currently, although the improvement of surgical techniques and the development of chemotherapy drugs have brought a certain degree of development to the treatment of osteosarcoma, the treatment of osteosarcoma has many shortcomings, and its treatment is limited. MiRNAs and exosomes can be used as diagnostic tools, and they play an important role in the occurrence and chemotherapy resistance of osteosarcoma. Therefore, providing a new method for the treatment of osteosarcoma is the key to solving this problem. To systematically summarize the research status of exoskeleton drug-loaded miRNA in osteosarcoma, we identified and evaluated 208 studies and found that exosome-carrying miRNA can be used as an index for the diagnosis and prognosis of osteosarcoma and share a certain relationship with chemosensitivity. In addition, exosomes can also be used as a carrier of genetic drugs able to regulate the progression of osteosarcoma. Based on the above findings, we propose suggestions for the future development of this field, aiming to bring new ideas for the early diagnosis and treatment of osteosarcoma.

miRNAs Flowing Up and Down: The Concerto of Psoriasis

Psoriasis is a chronic immune-mediated skin disease, whose hallmarks include keratinocyte hyperproliferation and CD4⁺ T cell subsets imbalance. Dysregulated microRNAs (miRNAs) identified in psoriasis have been shown to affect keratinocyte and T cell functions, with studies on the molecular mechanisms and intrinsic relationships of the miRNAs on the way. Here, we focus on the dysregulated miRNAs that contribute to the two hallmarks of psoriasis with the miRNA target genes confirmed. We review a network, in which, upregulated miR-31/miR-203/miR-155/miR-21 and downregulated miR-99a/miR-125b facilitate the excessive proliferation and abnormal differentiation of psoriatic keratinocytes; upregulated miR-210 and downregulated miR-138 work in concert to distort CD4⁺ T cell subsets balance in psoriasis. The miRNAs exert their functions through regulating key psoriasis-associated transcription factors including NF-κB and STAT3. Whether flowing up or down, these miRNAs collaborate to promote the development and maintenance of psoriasis.

Role of exosomal miR‑21 in the tumor microenvironment and osteosarcoma tumorigenesis and progression (Review)

Osteosarcoma is the most common bone tumor affecting both adolescents and children. Early detection is critical for the effective treatment of the disease. Derived from cancer cells, miR‑21 contained within exosomes in the tumor microenvironment may act on both cancer cells and the surrounding tumor microenvironment (TME), including immune cells, endothelial cells and fibroblasts. In human serum and plasm, the level of exosomal miR‑21 between osteosarcoma patients and healthy controls differs, supporting the role of miR‑21 as a biomarker for osteosarcoma. The involvement of a number of miR‑21 target genes in tumor progression suggests that miR‑21 may significantly affect the plasticity of cancer cells, leading to tumor progression, metastasis, angiogenesis and immune escape in osteosarcoma. Understanding the biogenesis and functions of exosomal miR‑21 is of great value for the diagnosis and therapy of cancer, including osteosarcoma. The present review discusses the role of miR‑21 in the tumor microenvironment, and in the development and progression of osteosarcoma, with an aim to summarize the functions of this miRNA in cancer.

Therapeutic Potential of Circular RNAs in Osteosarcoma

Osteosarcoma is the most common malignant bone tumor in children and adolescents. Multiagent chemotherapy, together with surgical removal of all detectable lesions, has improved the long-term survival rate to 65-70% in patients with localized osteosarcoma and to 25-30% in patients with metastatic osteosarcoma since the 1970s. However, the conventional strategy has not improved in recent decades. With accumulating knowledge of the natural circular RNA (circRNA) pathogenesis of osteosarcoma, the diagnostic and therapeutic potential of some circRNAs has been explored. Meanwhile, artificial circular RNAs have been designed as onco-microRNA inhibitors to exert antitumor functions. Therefore, natural and artificial circular RNAs, like other RNA counterparts, are attractive new classes of therapeutic molecules for the treatment of osteosarcoma. This review summarizes the latest progress in the relationship between circRNAs and the malignant phenotype of osteosarcoma and sheds light on the therapeutic potential of the two types of circular RNA in the clinic.

The Influence of Salinomycin on the Expression Profile of mRNAs Encoding Selected Caspases and MiRNAs Regulating their Expression in Endometrial Cancer Cell Line

BACKGROUND

Apoptosis could take place in the pathway dependent on death receptors or pathways dependent on mitochondria. In both, a key role is played by enzymes with protease activity, known as caspases.

AIM

The aim of this study was to assess the variances in the expression pattern of caspase-dependent signaling pathways in the endometrial cancer cell line when treated with salinomycin. Additionally, the changes in the level of miRNA that potentially regulate these mRNAs were evaluated.

MATERIALS AND METHODS

Endometrial cancer cells were treated with 1 μM of salinomycin for 12, 24 and 48 hours. Untreated cells made up the control culture. The molecular analysis consisted of screening mRNA and miRNA microarray expression profiles of caspases, and the evaluation of the expression of caspases 3,8 and 9 by RTqPCR, also on the protein level.

RESULTS AND DISCUSSION

It was observed that 5 of the 14 differentiating mRNAs were commonly found for all incubation times of the cells and they corresponded with CASP3, CASP8, and CASP9 genes. The highest impact probability was determined between CASP3(up-regulated) and hsa- miR- 30d (FC -2.01), CASP8 (down-regulated) and hsa-miR-21 (FC +1.39) and between CASP9 (upregulated) and hsa-miR-1271 (FC +1.71).

CONCLUSION

Salinomycin induces the apoptosis of endometrial cancer cells. The largest increase in activity was noted for caspases 3 and 9, while the expression of caspase 8 was decreased. Salinomycin causes a regulatory effect on the transcriptomes of mRNA and miRNA in in vitro endometrial cancer cells.

miRNA signatures in childhood sarcomas and their clinical implications

Progresses in multimodal treatments have significantly improved the outcomes for childhood cancer. Nonetheless, for about one-third of patients with Ewing sarcoma, rhabdomyosarcoma, or osteosarcoma steady remission has remained intangible. Thus, new biomarkers to improve early diagnosis and the development of precision-targeted medicine remain imperative. Over the last decade, remarkable progress has been made in the basic understanding of miRNAs function and in interpreting the contribution of their dysregulation to cancer development and progression. On this basis, this review focuses on what has been learned about the pivotal roles of miRNAs in the regulation of key genes implicated in childhood sarcomas.

LncRNA MEG3 influences the proliferation and apoptosis of psoriasis epidermal cells by targeting miR-21/caspase-8

Background

It was reported that microRNA-21(miR-21) was differentially expressed in the keratinocytes of psoriasis patients, and it may influence the apoptosis and proliferation of cells. The role of lncRNA maternally expressed gene3 (MEG3), a competing endogenous RNAs of miR-21, in the progression of psoriasis remains unclear. We aimed to unfold the influence of MEG3 and miR-21 on the proliferation and apoptosis of psoriasis epidermal cells.

Methods

50μg/L TNF-α was used to treat HaCaTs and NHEKs cells for 24 h, and then different experiments were conducted. qRT-PCR were applied for measuring the mRNA level of MEG3, miR-2, and caspase-8, and the protein expression of caspase-8 was measured with western blotting. Flow cytometry was used for assessing apoptosis. Cell proliferation was detected using MTT and colony formation assays. Dual luciferase reporter assay was applied for confirming the binding site between MEG3 and miR-21, miR-21 and Caspase-8.

Results

A cell model for in vitro studying the role of MEG3 in psoriasis pathophysiology was established using HaCaT and HHEKs. MEG3 was significantly down-regulated in HaCaT, HHEKs, and psoriatic skin samples. MEG3 inhibits proliferation and promotes apoptosis of Activated-HaCaT (Act-HaCaT) and Activated-HHEKs (Act- HHEK) by regulating miR-21, and the binding site between MEG3 and miR-21 was identified. We also found that miR-21 could inhibit the level of caspase-8 and identified the binding site between caspase-8 and miR-21. Some down-stream proteins of caspase-8, Cleaved caspase-8, cytc, and apaf-1 were regulated by miR-21 and MEG3.

Conclusion

MEG3/miR-21 axis may regulate the expression of caspase-8, and further influence the proliferation and apoptosis of psoriasis keratinocyte, Act-HaCaT and Act- HHEK. Therefore, our findings may provide a new thought for the study of pathogenesis and treatment of psoriasis.

Dissecting the functional role of microRNA 21 in osteosarcoma

Osteosarcoma (OS) is considered to be a malignant bone tumour that mainly affects the long bones, but it is also involved in other bones of the body. Currently, surgery and chemotherapy have achieved some response to patients with OS, but they are not increasing the survival rate as well as treatment options. Researchers made lot of drug options for OS, but yet, no treatment is existing in sight for the disease and needs a new insight into the molecular and signaling pathways for the disease. Now, it is necessary to develop a novel and alternative strategy for the prognosis, diagnosis and treatment options for OS. MicroRNAs (miRNAs) are a small non-coding RNA, and their size ranges from 18 to 22 nt in length. In the nucleus, miRNAs originate and transcribe into primary transcripts and later cleaved to produce stem loop-structured precursor nucleotides. microRNA 21 (miR-21) is considered to be a trivial marker for many diseases and has been upregulated in many cancers. Moreover, it plays a main role in proliferation, migration, invasion and apoptosis. miR-21 and its associated pathways are very important and play a critical role in the pathogenesis of OS and are considered to be a biomarker and a therapeutic target for OS. To our knowledge, there is no paper that demonstrates the responsibility and the role of miR-21 in OS and the number of studies related to miR-21 in OS is spare. Therefore, the main aim of this paper is to give an outline of the recent clinical investigation and importance of miR-21 in OS. It has been suggested that the up- and downregulation of miRNAs plays a crucial role in the pathogenesis and progression of OS. Normally, miR-21 was found to be upregulated in OS; however, we summarize the clinical relevance and the recent research findings associated with miR-21 in OS.

The mechanism study of lentiviral vector carrying methioninase enhances the sensitivity of drug-resistant gastric cancer cells to Cisplatin

Background

To investigate the mechanism of lentiviral vector carrying methioninase enhances the sensitivity of drug-resistant gastric cancer cells to Cisplatin.

Methods

Death receptors, anti-apoptotic protein, NF-κB, and TRAIL pathway-related factors were detected. The influence of LV-METase transfection on cell viability and pathway-related proteins were assessed by MTT method and western blot, respectively. Different treatments (NF-κB or caspase-3 inhibitor induction, TRAIL supplement, etc.) were performed in gastric cancer cells and the above parameters were analysed. Moreover, the connection between miR-21 and NF-κB or caspase-8 was determined by Chip and luciferase assay, respectively. LV-METase transfection drug-resistant gastric cancer cells were injected subcutaneously into mice.

Results

The expression of free MET, miR-21-5p, MDR1, P-gp, and DR5 was significantly increased in drug-resistant gastric cancer cell lines. When cells were transfected with LV-METase, intracellular TRAIL signalling was activated while NF-κB pathway was inhibited. Besides, enhanced TRAIL signalling or repressed NF-κB pathway can promote the sensitivity of drug-resistant strains to Cisplatin, and the combination shows more sensitive to sensitisation. LV-METase promoted TRAIL expression by reducing NF-κB, thereby contributing to the downregulation of P-gp and enhancing the susceptibility of drug-resistant gastric cancer cells to Cisplatin. Furthermore, miR-21 regulated by NF-κB mediated the expression of P-gp protein via inhibiting caspase-8, thus regulating Cisplatin-induced cell death.

Conclusions

Our results suggest that LV-METase has potential as a therapeutic agent for gastric cancer treatment.

Honokiol suppresses proliferation and induces apoptosis via regulation of the miR‑21/PTEN/PI3K/AKT signaling pathway in human osteosarcoma cells

Honokiol (HNK) is a small biphenolic compound, which exerts antineoplastic effects in various types of cancer. However, the mechanism underlying the antitumor effects of HNK in osteosarcoma (OS) cells is not yet fully understood. Emerging evidence has indicated that microRNAs (miRNAs/miRs) serve key roles in numerous pathological processes, including cancer. It has previously been reported that Chinese medicinal herbs harbor anticancer properties via modulating miRNA expression. Therefore, the present study aimed to determine whether HNK could suppress OS cell growth by regulating miRNA expression. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometric analysis were used to evaluate the cell proliferation and apoptosis in human OS cells after treatment with HNK, respectively. The results demonstrated that HNK inhibits proliferation and induces apoptosis of human OS cells in a dose-dependent manner. Furthermore, HNK-induced apoptosis was characterized by upregulation of proapoptotic proteins, including cleaved-caspase-3, cleaved-poly (ADP-ribose) polymerase and B-cell lymphoma 2 (Bcl-2)-associated X protein, and downregulation of the anti-apoptotic protein Bcl-2. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) verified that HNK was able to induce aberrant expression of miRNAs in human OS cells, and miR-21 was one of the miRNAs that was most significantly downregulated. To further investigate miR-21 function, the present study validated that HNK reduces miR-21 levels in a dose-dependent manner. In addition, restoration of miR-21 expression abrogated the suppressive effects of HNK on OS cells. Luciferase assay and western blot analysis identified that miR-21 inhibits the expression of phosphatase and tensin homolog (PTEN) by directly targeting its 3′-UTR. Notably, HNK was able to suppress the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway; however, it was reactivated by miR-21 overexpression. Taken together, these data indicated that HNK may inhibit proliferation and induce apoptosis of human OS cells by modulating the miR-21/PTEN/PI3K/AKT signaling pathway. Therefore, miR-21 may be considered a potential therapeutic target for the treatment of osteosarcoma with HNK.

miR-216a inhibits osteosarcoma cell proliferation, invasion and metastasis by targeting CDK14

Osteosarcoma (OS) has emerged as the most common primary musculoskeletal malignant tumour affecting children and young adults. Cyclin-dependent kinases (CDKs) are closely associated with gene regulation in tumour biology. Accumulating evidence indicates that the aberrant function of CDK14 is involved in a broad spectrum of diseases and is associated with clinical outcomes. MicroRNAs (miRNAs) are crucial epigenetic regulators in the development of OS. However, the essential role of CDK14 and the molecular mechanisms by which miRNAs regulate CDK14 in the oncogenesis and progression of OS have not been fully elucidated. Here we found that CDK14 expression was closely associated with poor prognosis and overall survival of OS patients. Using dual-luciferase reporter assays, we also found that miR-216a inhibits CDK14 expression by binding to the 3′-untranslated region of CDK14. Overexpression of miR-216a significantly suppressed cell proliferation, migration and invasion in vivo and in vitro by inhibiting CDK14 production. Overexpression of CDK14 in the miR-216a-transfected OS cells effectively rescued the suppression of cell proliferation, migration and invasion caused by miR-216a. In addition, Kaplan–Meier analysis indicated that miR-216a expression predicted favourable clinical outcomes for OS patients. Moreover, miR-216a expression was downregulated in OS patients and was negatively associated with CDK14 expression. Overall, these data highlight the role of the miR-216a/CDK14 axis as a novel pleiotropic modulator and demonstrate the associated molecular mechanisms, thus suggesting the intriguing possibility that miR-216a activation and CDK14 inhibition may be novel and attractive therapeutic strategies for treating OS patients.

Long non-coding RNA XIST regulates PDCD4 expression by interacting with miR-21-5p and inhibits osteosarcoma cell growth and metastasis

lncRNA-X-inactive specific transcript (lncRNA XIST) has been demonstrated to be a tumor suppressor involved in the pathogenesis and development of various cancers. However, the function of XIST and its working mechanism in osteosarcoma (OS) remain enigmatic. Firstly, we determined the expression of XIST in OS tissues and cell lines by quantitative reverse transcription-PCR (qRT-PCR) and explored whether aberrant XIST expression was associated with recurrence and short overall survival. Furthermore, the effects of XIST on osteosarcoma cells were studied by lentivirus mediated overexpression approach in vitro and in vivo. Detection of a set of epithelial-mesenchymal transition (EMT) markers was performed to explore whether XIST is involved in EMT. Finally, we investigated the regulatory mechanism of XIST acting as a competitive endogenous RNA (ceRNA) of miR-21-5p in OS progression and metastasis. lncRNA XIST was significantly downregulated in osteosarcoma tissues and osteosarcoma cells, and associated with recurrence and short overall survival in OS patients. XIST overexpression remarkably inhibited the proliferation of OS cells as well as the xenograft tumor formation in vivo. Both cell invasion and migration were inhibited by XIST overexpression via suppressing the EMT process. These results indicated that XIST functioned as a tumor suppressor in OS. Moreover, we found that miR-21-5p interacted with XIST by directly targeting the miRNA-binding site in the XIST sequence, and qRT-PCR results showed XIST and miR-21-5p could affect each other's expression, respectively. The following assays verified that the tumor suppressor, PDCD4 was a functional target of miR-21-5p in OS cells. Finally, we affirmed that XIST regulated PDCD4 expression by competitively binding to miR-21-5p. XIST inhibited cell proliferation and cell mobility by competitively binding to miR-21-5p and upregulating PDCD4 in OS. Our study demonstrated that lncRNA-XIST, which acts as a miRNA sponge, impedes miR-21-5p to maintain the expression of PDCD4, which contributes to the progression of OS. Our findings suggest that the newly identified XIST/miR-21-5p/PDCD4 axis could be a potential biomarker or therapeutic target for OS.