MicroRNA-221 induces cell survival and cisplatin resistance through PI3K/Akt pathway in human osteosarcoma

'Investigation of miRNAs That Affect the PI3K/AKT/mTOR Signaling Pathway in Endometrial Cancer'

Endometrial cancer is a prevalent type of cancer among women worldwide. The irregularity of the PI3K/AKT/mTOR signaling pathway plays a role in the pathogenesis of many cancer types. MicroRNAs are small noncoding RNAs that play crucial roles in the pathogenesis of different cancer types. MicroRNAs target many key components of the PI3K/AKT/mTOR pathway in human tumors. In this study the PI3K/AKT/mTOR pathway was affected in endometrial cancer, and the expression levels of miR-7, miR-17, miR-145, miR-155, miR-206, miR-221, miR-222 were determined. In addition, in silico analyses were examine the molecular interactions between miRNAs and target genes. Identifying dysregulated miRNA expression in endometrial cancer is important for developing miRNA-based therapeutic strategies. In our study, Grade 1 (n = 16), Grade 2 (n = 16), Grade 3 (n = 16), tissues diagnosed with endometrioid adeno carcinoma, control 1 (n = 16) secretory phase and control 2 (n = 16) proliferative phase healthy endometrial tissues without endometrial cancer were included. miRNA expression analysis was performed using the real-time PCR. In our study, the expression of miR-7-5p, miR-145-5p, and miR-206 decreased, whereas the expression of miR-17-5p, miR-221-3p, and miR-222-3p increased in endometrial cancer (p < 0,05). Statistically significant results were not obtained to for the expression levels of miR-21-5p and miR-155-5p. miR-7-5p targets PIK3CD, PIK3R3, PIK3CB and AKT3, miR-17-5p targets PIK3R1 and AKT3, miR-21-5p target PIK3R1, miR-145-5p target AKT3, miR-155-5p targets PIK3CA and PIK3R1, miR-206 target PIK3C2A, miR-221-3p and miR-222-3p target PIK3R1 as identified via in silico analysis. These results can shed light on the development of molecular-targeted therapy strategies. Treatment strategies can be developed by designing ASOs, LNAs, miRNA antagomirs, or miRNA sponges for upregulated miR-17-5p, miR-221-3p, and miR-222-3p, and miRNA mimics for downregulated miR-7-5p, miR-145-5p, and miR-206.

Interaction of ncRNAs and the PI3K/AKT/mTOR pathway: Implications for osteosarcoma

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents, and is characterized by high heterogeneity, high malignancy, easy metastasis, and poor prognosis. Recurrence, metastasis, and multidrug resistance are the main problems that limit the therapeutic effect and prognosis of OS. PI3K/AKT/mTOR signaling pathway is often abnormally activated in OS tissues and cells, which promotes the rapid development, metastasis, and drug sensitivity of OS. Emerging evidence has revealed new insights into tumorigenesis through the interaction between the PI3K/AKT/mTOR pathway and non-coding RNAs (ncRNAs). Therefore, we reviewed the interactions between the PI3K/AKT/mTOR pathway and ncRNAs and their implication in OS. These interactions have the potential to serve as cancer biomarkers and therapeutic targets in clinical applications.

Targeting pediatric solid tumors in the new era of RNA therapeutics

Despite substantial progress in pediatric cancer treatment, poor prognosis remained for patients with recurrent or metastatic disease, given the limitations of approved targeted treatments and immunotherapies. RNA therapeutics offer significant potential for addressing a broad spectrum of diseases, including cancer. Advances in manufacturing and delivery systems are paving the way for the rapid development of therapeutic RNAs for clinical applications. This review summarizes therapeutic RNA classifications and the mechanisms of action, highlighting their potential in manipulating major cancer-related pathways and biological effects. We also focus on the pre-clinical investigation of RNA molecules with efficient delivery systems for their therapeutic potential targeting pediatric solid tumors.

Mechanistic and therapeutic perspectives of miRNA-PTEN signaling axis in cancer therapy resistance

Cancer, being one of the most lethal illnesses, presents an escalating clinical dilemma on a global scale. Despite significant efforts and advancements in cancer treatment over recent decades, the persistent challenge of resistance to traditional chemotherapeutic agents and/or emerging targeted drugs remains a prominent issue in the field of cancer therapies. Among the frequently inactivated tumor suppressor genes in cancer, phosphatase and Tensin Homolog (PTEN) stands out, and its decreased expression may contribute to the emergence of therapeutic resistance. MicroRNAs (miRNAs), characterized by their short length of 22 nucleotides, exert regulatory control over target mRNA expression by binding to complementary sequences. Recent findings indicate that microRNAs play varied regulatory roles, encompassing promotion, suppression, and dual functions on PTEN, and their aberration is implicated in heightened resistance to anticancer therapies. Significantly, recent research has revealed that competitive endogenous RNAs (ceRNAs) play a pivotal role in influencing PTEN expression, and the regulatory network involving circRNA/lncRNA-miRNA-PTEN is intricately linked to resistance in various cancer types to anticancer therapies. Finally, our findings showcase that diverse approaches, such as herbal medicine, small molecule inhibitors, low-intensity ultrasound, and engineered exosomes, can effectively overcome drug resistance in cancer by modulating the miRNA-PTEN axis.

Research progress on the role of lncRNA, circular RNA, and microRNA networks in regulating ferroptosis in osteosarcoma

Noncoding RNAs (ncRNAs) do not participate in protein-coding. Ferroptosis is a newly discovered form of cell death mediated by reactive oxygen species and lipid peroxidation. Recent studies have shown that ncRNAs such as microRNAs, long noncoding RNAs, circular RNAs, and ferroptosis are involved in the occurrence and development of osteosarcoma (OS). Studies have confirmed that ncRNAs participate in the development of OS by regulating the ferroptosis. However, systematic summary on this topic are still lacking. This review summarises the potential role of ncRNAs in the diagnosis, treatment, drug resistance, and prognosis of OS and the basis for diagnosing, preventing, and treating clinical OS and developing effective drugs. This review summarises the latest research progress on ncRNAs that regulate ferroptosis in OS, attempts to clarify the molecular mechanisms by which ncRNAs regulate ferroptosis in the pathogenesis of OS, and elaborates on the involvement of ferroptosis in OS from the perspective of ncRNAs.

Deciphering chemoresistance in osteosarcoma: Unveiling regulatory mechanisms and function through the lens of noncoding RNA

Osteosarcoma (OS) is a primary malignant bone tumor and is prevalent in children, adolescents, and elderly individuals. It has the characteristics of high invasion and metastasis. Neoadjuvant chemotherapy combined with surgical resection is the most commonly used treatment for OS. However, the efficacy of OS is considerably diminished by chemotherapy resistance. In recent years, noncoding RNAs (ncRNAs), including microRNAs, long noncoding RNAs, and circular RNAs, are hot topics in the field of chemotherapy resistance research. Several studies have demonstrated that ncRNAs are substantially associated with chemoresistance in OS. Thus, the present study overviews the abnormally expressed ncRNAs in OS and the molecular mechanisms involved in chemoresistance, with an emphasis on their function in promoting or inhibiting chemoresistance. ncRNAs are expected to become potential therapeutic targets for overcoming drug resistance and predictive biomarkers in OS, which are of great significance for enhancing the therapeutic effect and improving the prognosis.

The Landscape of microRNAs in Bone Tumor: A Comprehensive Review in Recent Studies

Cancer, the second greatest cause of mortality worldwide, frequently causes bone metastases in patients with advanced-stage carcinomas such as prostate, breast, and lung cancer. The existence of these metastases contributes to the occurrence of skeletal-related events (SREs), which are defined by excessive pain, pathological fractures, hypercalcemia, and spinal cord compression. These injurious incidents leave uncomfortably in each of the cancer patient's life quality. Primary bone cancers, including osteosarcoma (OS), chondrosarcoma (CS), and Ewing's sarcoma (ES), have unclear origins. MicroRNA (miRNA) expression patterns have been changed in primary bone cancers such as OS, CS, and ES, indicating a role in tumor development, invasion, metastasis, and treatment response. These miRNAs are persistent in circulation and exhibit distinct patterns in many forms of bone tumors, making them potential biomarkers for early detection and treatment of such diseases. Given their crucial regulatory functions in various biological processes and conditions, including cancer, this study aims to look at miRNAs' activities and possible contributions to bone malignancies, focusing on OS, CS, and ES. In conclusion, miRNAs are valuable tools for diagnosing, monitoring, and predicting OS, CS, and ES outcomes. Further research is required to fully comprehend the intricate involvement of miRNAs in these bone cancers and to develop effective miRNA-based treatments.

New emerging targets in osteosarcoma therapy: PTEN and PI3K/Akt crosstalk in carcinogenesis

Osteosarcoma (OS) is a malignant bone carcinoma that affects people in childhood and adulthood. The heterogeneous nature and chromosomal instability represent certain characteristics of OS cells. These cancer cells grow and migrate abnormally, making the prognosis undesirable for patients. Conventional and current treatments fail to completely eradicate tumor cells, so new therapeutics targeting genes may be considered. PI3K/Akt is a regulator of events such as growth, cell death, migration, and differentiation, and its expression changes during cancer progression. PTEN reduces PI3K/Akt expression, and its mutations and depletions have been reported in various tumors. Experimental evidence shows that there is upregulation of PI3K/Akt and downregulation of PTEN in OS. Increasing PTEN expression may suppress PI3K/Akt to minimize tumorigenesis. In addition, PI3K/Akt shows a positive association with growth, metastasis, EMT and metabolism of OS cells and inhibits apoptosis. Importantly, overexpression of PI3K/Akt causes drug resistance and radio-resistance and its level can be modulated by miRNAs, lncRNAs and circRNAs. Silencing PI3K/Akt by compounds and drugs can suppress OS. Here, we review in detail the function of the PTEN/PI3K/Akt in OS, revealing its biological function, function in tumor progression, resistance to therapy, and pharmacological significance.

The predictive value of MiR-221 in cancer chemoresistance: a systematic review and meta-analysis

BACKGROUND

Many studies have reported that microRNA-221 (miR-221) is abnormally expressed in various cancers, and there has not been a study to systematically analyze the association between miR-221 and chemoresistance in different cancers.

METHODS

We systematically searched PubMed, Web of Science, Ovid, and Cochrane for relevant studies. The pooled odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs) were used to estimate.

RESULTS

A total of 30 studies with 1670 patients were enrolled in our study. Thirteen cancer types have been studied, and traditional chemotherapy, targeted drugs, endocrine therapy, chemoradiotherapy, and other treatments were used. High miR-221 expression was associated with poor chemotherapy response in most studies, and the meta-analysis confirmed this result (OR = 3.64, 95%CI: 1.73-7.62, p = 0.001). Besides, the higher level of miR-221 was related to shorter overall survival (OS) (HR = 2.16, 95%CI: 1.47-3.16, p < 0.001) and progression-free survival (PFS) (HR = 1.81, 95%CI: 1.51-2.16, p < 0.001) in patients after chemotherapy.

CONCLUSION

Our results highlight that high miR-221 expression has possible associations with chemoresistance and poor prognosis in multiple cancers. Further studies are needed to discover the molecular mechanisms underlying these associations to provide a solid evidence base for it being used as biomarkers of response to chemotherapeutic interventions in cancer.

MicroRNAs involved in human skin burns, wound healing and scarring

MicroRNAs are small, non-coding RNAs that regulate gene expression, and consequently protein synthesis. Downregulation and upregulation of miRNAs and their corresponding genes can alter cell apoptosis, proliferation, migration and fibroproliferative responses following a thermal injury. This review summarises the evidence for altered human miRNA expression post-burn, and during wound healing and scarring. In addition, the most relevant miRNA targets and their roles in potential pathways are described. Previous studies using molecular techniques have identified 197 miRNAs associated with human wound healing, burn wound healing and scarring. Five miRNAs alter the expression of fibroproliferative markers, proliferation and migration of fibroblasts and keratinocytes post-burn: hsa-miR-21 and hsa-miR-31 are increased after wounding, and hsa-miR-23b, hsa-miR-200b and hsa-let-7c are decreased. Four of these five miRNAs are associated with the TGF-β pathway. In the future, large scale, in vivo, longitudinal human studies utilising a range of cell types, ethnicity and clinical healing outcomes are fundamental to identify burn wound healing and scarring specific markers. A comprehensive understanding of the underlying pathways will facilitate the development of clinical diagnostic or prognostic tools for better scar management and the identification of novel treatment targets for improved healing outcomes in burn patients.

Functional role of MicroRNA/PI3K/AKT axis in osteosarcoma

Osteosarcoma (OS) is a primary malignant bone tumor that occurs in children and adolescents, and the PI3K/AKT pathway is overactivated in most OS patients. MicroRNAs (miRNAs) are highly conserved endogenous non-protein-coding RNAs that can regulate gene expression by repressing mRNA translation or degrading mRNA. MiRNAs are enriched in the PI3K/AKT pathway, and aberrant PI3K/AKT pathway activation is involved in the development of osteosarcoma. There is increasing evidence that miRNAs can regulate the biological functions of cells by regulating the PI3K/AKT pathway. MiRNA/PI3K/AKT axis can regulate the expression of osteosarcoma-related genes and then regulate cancer progression. MiRNA expression associated with PI3K/AKT pathway is also clearly associated with many clinical features. In addition, PI3K/AKT pathway-associated miRNAs are potential biomarkers for osteosarcoma diagnosis, treatment and prognostic assessment. This article reviews recent research advances on the role and clinical application of PI3K/AKT pathway and miRNA/PI3K/AKT axis in the development of osteosarcoma.

Endothelial plasticity across PTEN and Hippo pathways: A complex hormetic rheostat modulated by extracellular vesicles

Vascularization is a multifactorial and spatiotemporally regulated process, essential for cell and tissue survival. Vascular alterations have repercussions on the development and progression of diseases such as cancer, cardiovascular diseases, and diabetes, which are the leading causes of death worldwide. Additionally, vascularization continues to be a challenge for tissue engineering and regenerative medicine. Hence, vascularization is the center of interest for physiology, pathophysiology, and therapeutic processes. Within vascularization, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and Hippo signaling have pivotal roles in the development and homeostasis of the vascular system. Their suppression is related to several pathologies, including developmental defects and cancer. Non-coding RNAs (ncRNAs) are among the regulators of PTEN and/or Hippo pathways during development and disease. The purpose of this paper is to review and discuss the mechanisms by which exosome-derived ncRNAs modulate endothelial cell plasticity during physiological and pathological angiogenesis, through the regulation of PTEN and Hippo pathways, aiming to establish new perspectives on cellular communication during tumoral and regenerative vascularization.

A spotlight on the interplay of signaling pathways and the role of miRNAs in osteosarcoma pathogenesis and therapeutic resistance

Osteosarcoma (OS) is one of the most common bone cancers that constantly affects children, teenagers, and young adults. Numerous epigenetic elements, such as miRNAs, have been shown to influence OS features like progression, initiation, angiogenesis, and treatment resistance. The expression of numerous genes implicated in OS pathogenesis might be regulated by miRNAs. This effect is ascribed to miRNAs' roles in the invasion, angiogenesis, metastasis, proliferation, cell cycle, and apoptosis. Important OS-related mechanistic networks like the WNT/b-catenin signaling, PTEN/AKT/mTOR axis, and KRAS mutations are also affected by miRNAs. In addition to pathophysiology, miRNAs may influence how the OS reacts to therapies like radiotherapy and chemotherapy. With a focus on how miRNAs affect OS signaling pathways, this review seeks to show how miRNAs and OS are related.

Mechanisms of microRNA action in rectal cancer radiotherapy

ABSTRACT

Preoperative neoadjuvant chemoradiotherapy, combined with total mesorectal excision, has become the standard treatment for advanced localized rectal cancer (RC). However, the biological complexity and heterogeneity of tumors may contribute to cancer recurrence and metastasis in patients with radiotherapy-resistant RC. The identification of factors leading to radioresistance and markers of radiosensitivity is critical to identify responsive patients and improve radiotherapy outcomes. MicroRNAs (miRNAs) are small, endogenous, and noncoding RNAs that affect various cellular and molecular targets. miRNAs have been shown to play important roles in multiple biological processes associated with RC. In this review, we summarized the signaling pathways of miRNAs, including apoptosis, autophagy, the cell cycle, DNA damage repair, proliferation, and metastasis during radiotherapy in patients with RC. Also, we evaluated the potential role of miRNAs as radiotherapeutic biomarkers for RC.

No Effect on Tumorigenesis in MG63 Cells Induced by Co-Cultured Mesenchymal Stem Cells

Osteosarcoma is a kind of bone tumor with an extremely high malignant degree and often occurs in adolescents. Mesenchymal stem cells are believed to play an important role in the microenvironment of osteosarcoma, but whether they promote or inhibit the development of osteosarcoma is controversial. In this study, the coexpression of mesenchymal stem cells (MSCs) with osteosarcoma cell MG63 was used to explore the effect of MSCs on MG63. We found that co-culture of MSCs with MG63 did not affect the proliferation, invasion, and migration of MG63 cells, nor did it significantly affect the epithelial- and glial-mesenchymal transformation of MG63 cells. Therefore, in this study, we obtained a new concept that MSCs neither promote nor inhibit the occurrence and development of osteosarcoma.

Exosomal MiRNAs in Osteosarcoma: Biogenesis and Biological Functions

MiRNAs are a group of non-coding RNA molecules that function in mRNA translational inhibition via base-pairing with complementary sequences in target mRNA. In oncology, miRNAs have raised great attention due to their aberrant expression and pivotal roles in the pathogenesis of multiple malignancies including osteosarcoma. MiRNAs can be transported by exosome, the nano-extracellular vesicle with a diameter of 30–150 nm. Recently, a growing number of studies have demonstrated that exosomal miRNAs play a critical role in tumor initiation and progression, by exerting multiple biological functions including metastasis, angiogenesis, drug resistance and immunosuppression. In this review, we aim to depict the biogenesis of exosomal miRNAs and summarize the potential diagnostic and therapeutic functions of exosomal miRNAs in osteosarcoma.

MicroRNAs and osteosarcoma: Potential targets for inhibiting metastasis and increasing chemosensitivity

Osteosarcoma (OS) is the third most common cancer in young adults after lymphoma and brain cancer. Metastasis, like other cellular events, is dependent on signaling pathways; a series of changes in some proteins and signaling pathways pave the way for OS cells to invade and migrate. Ezrin, TGF-β, Notch, RUNX2, matrix metalloproteinases (MMPs), Wnt/β-catenin, and phosphoinositide 3-kinase (PI3K)/AKT are among the most important of these proteins and signaling pathways. Despite the improvements in treating OS, the overall survival of patients suffering from the metastatic disease has not experienced any significant change after surgical treatments and chemotherapy and 5-years overall survival in patients with metastatic OS is about 20%. Studies have shown that overexpression or inhibition of some microRNAs (miRNAs) has significant effects in limiting the invasion and migration of OS cells. The results of these studies highlight the potential of the clinical application of some miRNA mimics and miRNA inhibitors (antagomiRs) to inhibit OS metastasis in the future. In addition, some studies have shown that miRNAs are associated with the most important drug resistance mechanisms in OS, and some miRNAs are highly effective targets to increase chemosensitivity. The results of these studies suggest that miRNA mimics and antagomiRs may be helpful to increase the efficacy of conventional chemotherapy drugs in the treatment of metastatic OS. In this article, we discussed the role of various signaling pathways and the involved miRNAs in the metastasis of OS, attempting to provide a comprehensive review of the literature on OS metastasis and chemosensitivity.

Molecular signaling pathways as potential therapeutic targets in osteosarcoma

Among primary bone malignancies, osteosarcoma (OS) is the most common form causing morbidity and mortality in both adults and children. The interesting point about this malignancy is that nearly 10-20% of its newly diagnosed cases have developed metastasis. This adds up to the fact that the survival rate of both metastatic and non-metastatic patients of osteosarcoma hasn't changed in the past 30 years and suggests that we need to revise our therapeutic options for OS. In recent years, diverse signaling pathways have drawn the attention of the scientific community since they can be great candidates for treating complicated diseases such as cancer. In this review, we have tried to explain the pathophysiology of osteosarcoma by the help of different signaling pathways taking part in its initiation/progression and investigate how this pathway can be targeted for providing more efficient methods.

Cancer drug resistance related microRNAs: recent advances in detection methods

MiRNAs are related to cancer drug resistance through various mechanisms. The advanced detection methods for the miRNAs are reviewed.

Preparation of polycation with hydroxyls for enhanced delivery of miRNA in osteosarcoma therapy

Osteosarcoma, a malignant bone tumor usually occurs in children and adolescents, has a high rate of death and disability which bringing great pains to society and families. Improving treatment approaches...

Crosstalk between miRNA and PI3K/AKT/mTOR signaling pathway in cancer

Phosphoinositide-3 kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway is one of the most important proliferative signaling pathways with critical undeniable function in various aspects of cancer initiation/progression, including proliferation, apoptosis, metastasis, angiogenesis, and drug resistance. On the other hand, numerous genetic alterations in the key genes involved in the PI3K/AKT/mTOR signaling pathway have been identified in multiple solid and hematological tumors. In addition, accumulating recent evidences have demonstrated a reciprocal interaction between this signaling pathway and microRNAs, a large group of small non-coding RNAs. Therefore, in this review, it was attempted to discuss about the interaction between key components of PI3K/AKT/mTOR signaling pathway with various miRNAs and their importance in cancer biology.

Overexpression of FGF2 delays the progression of osteonecrosis of the femoral head activating the PI3K/Akt signaling pathway

BACKGROUND

The purpose of the current study was to explore the role and underlying mechanism of FGF-2 in dexamethasone (DEX)-induced apoptosis in MC3T3-E1 cells.

METHODS

GSE21727 was downloaded from the Gene Expression Omnibus (GEO) database to identify the differentially expressed genes (DEGs) by the limma/R package. MC3T3-E1 cells were exposed to DEX at different concentrations (0, 10^-8, 10^-7, 10^-6, 10^-5 and 10^-4 mol/L), and cell viability, flow cytometry and TUNEL assay were used to detect cell proliferation and apoptosis. An FGF-2-pcDNA3 plasmid (oe-FGF-2) was used to overexpress FGF-2, and western blotting was conducted to detect protein expression.

RESULTS

We found that FGF-2 was downregulated in the DEX-treated group. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses indicated that DEGs were associated with PI3K/Akt signaling pathway. DEX downregulated FGF-2 gene and protein expression, inhibited viability and induced MC3T3-E1 cell apoptosis. Overexpression of FGF-2 reversed DEX-induced apoptosis in MC3T3-E1 cells. FGF-2-mediated anti-apoptosis was impaired by inactivating the PI3K/AKT pathway with LY294002. Moreover, overexpression of FGF2 delayed the progression of DEX-induced osteonecrosis of the femoral head (ONFH) animal model by regulation PI3K/Akt signaling pathway.

CONCLUSION

In conclusion, FGF-2 is effective at inhibiting DEX-induced MC3T3-E1 cell apoptosis through regulating PI3K/Akt signaling pathway.

The role of microRNAs in the osteogenic and chondrogenic differentiation of mesenchymal stem cells and bone pathologies

Mesenchymal stem cells (MSCs) have been identified in many adult tissues. MSCs can regenerate through cell division or differentiate into adipocytes, osteoblasts and chondrocytes. As a result, MSCs have become an important source of cells in tissue engineering and regenerative medicine for bone tissue and cartilage. Several epigenetic factors are believed to play a role in MSCs differentiation. Among these, microRNA (miRNA) regulation is involved in the fine modulation of gene expression during osteogenic/chondrogenic differentiation. It has been reported that miRNAs are involved in bone homeostasis by modulating osteoblast gene expression. In addition, countless evidence has demonstrated that miRNAs dysregulation is involved in the development of osteoporosis and bone fractures. The deregulation of miRNAs expression has also been associated with several malignancies including bone cancer. In this context, bone-associated circulating miRNAs may be useful biomarkers for determining the predisposition, onset and development of osteoporosis, as well as in clinical applications to improve the diagnosis, follow-up and treatment of cancer and metastases. Overall, this review will provide an overview of how miRNAs activities participate in osteogenic/chondrogenic differentiation, while addressing the role of miRNA regulatory effects on target genes. Finally, the role of miRNAs in pathologies and therapies will be presented.

PharmaNet: Pharmaceutical discovery with deep recurrent neural networks

The discovery and development of novel pharmaceuticals is an area of active research mainly due to the large investments required and long payback times. As of 2016, the development of a novel drug candidate required up to $ USD 2.6 billion in investment for only 10% rate of approval by the FDA. To help decreasing the costs associated with the process, a number of in silico approaches have been developed with relatively low success due to limited predicting performance. Here, we introduced a machine learning-based algorithm as an alternative for a more accurate search of new pharmacological candidates, which takes advantage of Recurrent Neural Networks (RNN) for active molecule prediction within large databases. Our approach, termed PharmaNet was implemented here to search for ligands against specific cell receptors within 102 targets of the DUD-E database, which contains 22886 active molecules. PharmaNet comprises three main phases. First, a SMILES representation of the molecule is converted into a raw molecular image. Second, a convolutional encoder processes the data to obtain a fingerprint molecular image that is finally analyzed by a Recurrent Neural Network (RNN). This approach enables precise predictions of the molecules' target on the basis of the feature extraction, the sequence analysis and the relevant information filtered out throughout the process. Molecule Target prediction is a highly unbalanced detection problem and therefore, we propose that an adequate evaluation metric of performance is the area under the Normalized Average Precision (NAP) curve. PharmaNet largely surpasses the previous state-of-the-art method with 97.7% in the Receiver Operating Characteristic curve (ROC-AUC) and 65.5% in the NAP curve. We obtained a perfect performance for human farnesyl pyrophosphate synthase (FPPS), which is a potential target for antimicrobial and anticancer treatments. We decided to test PharmaNet for activity prediction against FPPS by searching in the CHEMBL data set. We obtained three (3) potential inhibitors that were further validated through both molecular docking and in silico toxicity prediction. Most importantly, one of this candidates, CHEMBL2007613, was predicted as a potential antiviral due to its involvement on the PCDH17 pathway, which has been reported to be related to viral infections.

Up-regulation of LINC00619 promotes apoptosis and inhibits proliferation, migration and invasion while promoting apoptosis of osteosarcoma cells through inactivation of the HGF-mediated PI3K-Akt signalling pathway

This study is performed to evaluate the role of long noncoding RNA (lncRNA) LINC00619 in osteosarcoma through the PI3K-Akt signalling pathway by binding to HGF. Osteosarcoma and osteochondroma tissues from patients were collected. The relationship between lncRNA LINC00619 and HGF was proved by the dual-luciferase reporter gene assay. The expression patterns of lncRNA LINC00619 as well as the levels of proliferating cell nuclear antigen (PCNA), hepatocyte growth factor (HGF), phosphoinositide 3-kinase (PI3K), protein kinase B (Akt), Bax, Bcl-2, alkaline phosphatase (ALP), and osteopontin (OPN) were detected by RT-qPCR and Western blot analysis. In addition, MTT assay, flow cytometry, scratch test, and Transwell assay were performed to assess the cell proliferation, cell cycle distribution, apoptosis, cell migration, and invasion in each group, respectively. Osteosarcoma tissues presented with elevated positive expression rate of HGF, up-regulated expression levels of PCNA, HGF, PI3K, Akt, Bcl-2, ALP and OPN, and down-regulated expressions of Bax and LINC00619. HGF was verified as a target gene of lncRNA LINC00619. LINC00619 was found to down-regulate the expressions of PCNA, HGF, PI3K, Akt, Bcl-2, ALP, and OPN in osteosarcoma cells. Up-regulation of lncRNA LINC00619 decreased cell growth, migration intensity, and invasion ability, but enhanced the apoptosis rate of osteosarcoma cells. Our findings suggest that lncRNA LINC00619 inhibits proliferation, migration and invasion and improves apoptosis of osteosarcoma cells through the inhibition of the activation of the HGF-dependent PI3K-Akt signalling pathway.

DNA damage response and repair in osteosarcoma: Defects, regulation and therapeutic implications

Osteosarcoma (OS) is the most common primary bone malignancy in children and adolescents which has the survival rate of 20% in its advanced stages. Osteosarcomas are mostly resistance to our common treatments. DNA damage response (DDR) is a specialized multistep process containing abundant proteins which are necessary for the survival of any cell and organism. DDR machinery detects a diversity of DNA lesions and inhibits the cell cycle progression if these lesions are not repairable. DDR is involved in aging, age-related diseases, and cancer. In recent years, DDR inhibitors have gained the attention of researches due to their potentials in offering novel therapeutic targets and improving the response of many cancers to either chemo- or radio-therapy. In this regard, we tried to gather a great body of evidence about the role of DDR ingredients in osteosarcoma's initiation/progression, prognosis, and treatment.

Research Progress of MicroRNA in Chemotherapy Resistance of Osteosarcoma

Osteosarcoma (OS) is a malignant tumor prevalent in adolescents; however, a clinically effective treatment for this malignancy is lacking. The lack of effective treatment methods and factors, such as recurrence and drug resistance, further dampen the prospect of clinically treating OS. In recent years, small molecule microRNAs (miRNAs) with a length of approximately 20-24 nucleotides have gradually attracted the attention of the medical community. Studies have found that miRNAs can regulate the cell cycle, apoptosis, cell proliferation, and cell proliferation. The metabolic response of cancer cells, invasion and metastasis of cancer cells, and angiogenesis play an important role in the process of tumorigenesis. miRNAs regulate gene expression by regulating mRNA expression after transcription. A large amount of data from many studies indicate that they have diagnostic and prognostic biomarker effects in OS and are involved in regulating the metabolism of cancer cells and resistance or sensitivity to chemotherapy drugs. Chemotherapy resistance is one of the most critical problems in clinically treating OS. A large number of basic studies and systematic summaries are required to provide a theoretical basis for elucidating the mechanism and drug development of chemotherapeutic agents. Therefore, this article discusses the role of miRNAs in OS resistance. Herein, the related research progress of the studies is reviewed to provide more useful information for the development of effective therapy.

Recent Insights into Therapy Resistance in Osteosarcoma

Osteosarcoma, the most common bone malignancy of childhood, has been a challenge to treat and cure. Standard chemotherapy regimens work well for many patients, but there remain minimal options for patients with progressive or resistant disease, as clinical trials over recent decades have failed to significantly improve survival. A better understanding of therapy resistance is necessary to improve current treatments and design new strategies for future treatment options. In this review, we discuss known mechanisms and recent scientific advancements regarding osteosarcoma and its patterns of resistance against chemotherapy, radiation, and other newly-introduced therapeutics.

An update on the roles of circular RNAs in osteosarcoma

Osteosarcoma is the most common primary bone malignancy and is a neoplasm thought to be derived from the bone‐forming mesenchymal stem cells. Aberrant activation of oncogenes and inactivation of tumour suppressor genes by somatic mutations and epigenetic mechanisms play a pivotal pathogenic role in osteosarcoma. Aside from alterations in these protein‐coding genes, it has now been realized that dysregulation of non‐coding RNAs (ncRNAs), including microRNAs (miRNAs), long non‐coding RNAs (lncRNAs) and the recently discovered circular RNAs (circRNAs), is crucial to the initiation and progression of osteosarcoma. CircRNAs are single‐stranded RNAs that form covalently closed loops and function as an important regulatory element of the genome through multiple machineries. Recently, an increasing number of studies suggested that circRNAs also played critical roles in osteosarcoma. This review summarizes recent development and progression in circRNA transcriptome analysis and their functions in the modulation of osteosarcoma progression.

Overcoming cisplatin resistance in osteosarcoma through the miR-199a-modulated inhibition of HIF-1α

Dysregulation of miRNAs has been shown to contribute to multiple tumorigenic processes, as well as to correlate with tumour progression and prognosis. miR-199a has been shown to be dysregulated in multiple tumour types. However, the association between miR-199a and the chemoresistance features of osteosarcoma are not well understood, the target genes for miR-199a and the regulatory mechanisms are also unknown. In the present study, we demonstrated that miR-199a is expressed at low levels in osteosarcoma cells and patient samples. By the selection and establishment of cisplatin resistant osteosarcoma cell line, we observed a correlation between miR-199a and cisplatin resistance in osteosarcoma cells: resistant cells exhibit attenuated miR-199a expressions and exogenous overexpression of miR-199a sensitizes osteosarcoma cells to cisplatin. Moreover, we identified HIF-1α as a direct target for miR-199a. Intriguingly, cisplatin resistant osteosarcoma cells display significantly elevated HIF-1α expression under hypoxia. We report here overexpression of miR-199a resensitizes cisplatin resistant cells to cisplatin through inhibition of HIF-1α in vitro and in vivo. Finally, by analysing the clinical osteosarcoma patient samples, we demonstrate a reverse correlation between miR-199a and HIF-1α mRNAs. Our study will provide mechanisms for the miRNA-mediated anticancer therapy and miR-199a may be considered a promising therapeutic agent for osteosarcoma patients who fail to respond to conventional chemotherapy.

Bone Microenvironment and Osteosarcoma Metastasis

The bone microenvironment is an ideal fertile soil for both primary and secondary tumors to seed. The occurrence and development of osteosarcoma, as a primary bone tumor, is closely related to the bone microenvironment. Especially, the metastasis of osteosarcoma is the remaining challenge of therapy and poor prognosis. Increasing evidence focuses on the relationship between the bone microenvironment and osteosarcoma metastasis. Many elements exist in the bone microenvironment, such as acids, hypoxia, and chemokines, which have been verified to affect the progression and malignance of osteosarcoma through various signaling pathways. We thoroughly summarized all these regulators in the bone microenvironment and the transmission cascades, accordingly, attempting to furnish hints for inhibiting osteosarcoma metastasis via the amelioration of the bone microenvironment. In addition, analysis of the cross-talk between the bone microenvironment and osteosarcoma will help us to deeply understand the development of osteosarcoma. The cellular and molecular protagonists presented in the bone microenvironment promoting osteosarcoma metastasis will accelerate the exploration of novel therapeutic strategies towards osteosarcoma.

miRNA-216 knockdown has effects to suppress osteosarcoma via stimulating PTEN

The aim of this study is to explain the effects and mechanism of miRNA-216 in osteosarcoma. We firstly evaluated the PTEN expression in 30 pairs of tumor and adjacent tissues which were from the 30 osteosarcoma patients. In the following cell experiments, we measured the cell proliferation, cell cycle, cell invasion, and migration abilities of NC (normal control) group, BL (blank) group, siRNA (miRNA-216 inhibitor) group, and siRNA+PTEN inhibitor group. Furthermore, we measured the relative protein expression of difference groups by WB to explain the mechanism of miRNA-216 in osteosarcoma. The PTEN was confirmed the target gene of miRNA-216 by double luciferase target test. In conclusion, miRNA-216 was an oncogene in osteosarcoma. miRNA-216 knockdown had effects to suppress cancer cell proliferation, invasion and migration and improve cell apoptosis by keeping in G1 phase via PTEN.

MicroRNA‑22 regulates autophagy and apoptosis in cisplatin resistance of osteosarcoma

Osteosarcoma (OS) is a primary malignant tumor of bone tissue. Effective chemotherapy may improve the survival of patients with OS. MicroRNAs (miRs) serve significant roles in the regulatory function of tumorigenesis and chemosensitivity of different types of cancer. miR‑22 has been revealed to inhibit the proliferation and migration of OS cells, as well as increasing their sensitivity to cisplatin (CDDP). The mechanisms of action behind the functions of miR‑22 in OS drug resistance require investigation. Therefore, in the present study, the human OS cell lines (MG‑63, U2OS, Saos2 and OS9901) and a drug‑resistant cell line (MG‑63/CDDP) were cultured. Cell proliferation, apoptosis and autophagy assays were performed to investigate the proliferation, apoptosis and autophagy of cell lines transfected with miR‑22 mimic. Reverse transcription‑quantitative polymerase chain reaction and western blot analysis were performed to investigate the expression levels of associated genes. The results revealed that miR‑22 inhibited the proliferation of MG‑63 cells and MG‑63/CDDP cells, and enhanced the anti‑proliferative ability of CDDP. miR‑22 induced apoptosis and inhibited autophagy of MG‑63 cells and MG‑63/CDDP cells. Apoptosis‑related genes, including caspase‑3 and Bcl‑2‑associated X protein were upregulated, while B‑cell lymphoma‑2 was downregulated in both cell lines transfected with the miR‑22 mimic. Autophagy protein 5, beclin1 and microtubules‑associated protein 1 light chain 3 were downregulated in both cell lines transfected with miR‑22 mimic. Furthermore, the in vitro and in vivo expression levels of metadherin (MTDH) in the OS/OS‑CDDP‑resistant models were downregulated following transfection with the miR‑22 mimic. Therefore, the results of the present study suggested that miR‑22 promoted CDDP sensitivity by inhibiting autophagy and inducing apoptosis in OS cells, while MTDH may serve a positive role in inducing CDDP resistance of OS cells.

PTEN in osteosarcoma: Recent advances and the therapeutic potential

Osteosarcoma is the most common primary malignant bone tumor, predominantly occurring in children and adolescents. Despite treated with surgery and neoadjuvant chemotherapy, osteosarcoma has a high potential of local recurrence and lung metastasis. Overall survival rates for osteosarcoma have plateaued in the past four decades, therefore, identification of novel targets and development of more effective treatment strategies are urgent. Phosphatase and tensin homolog (PTEN) is a tumor suppressor gene that negatively regulates the phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway. Over half of clinical osteosarcoma samples presented loss or low expression of PTEN, which usually indicated an advanced stage of tumor and a poor prognosis. The expression of PTEN is regulated by epigenetic silence, transcription regulation, post-translational modifications, and protein interactions in osteosarcoma. Therefore, explicating regulations to restore the anti-tumor function of PTEN might provide novel targeted therapies for osteosarcoma. Preclinical evidence suggested directly targeting the altered PTEN in osteosarcoma was promising. Current clinical application of PTEN related therapies in osteosarcoma are PI3K/mTOR inhibitors, and these drugs have shown the favorable efficacy in patients with advanced osteosarcoma.

Down-regulation of PDGFRβ suppresses invasion and migration in osteosarcoma cells by influencing epithelial-mesenchymal transition

Osteosarcoma (OS) is the most common malignant bone tumor primarily influencing children and adults. Approximately one‐fifth of patients have micrometastasis in the lungs when OS is diagnosed. Platelet‐derived growth factor receptor (PDGFR) beta (PDGFRβ) is a subtype of PDGFR. PDGFRβ has been noted to be highly expressed in OS cell lines and patient specimens, and is associated with metastasis and poor prognosis of OS. However, mechanistic insights into the exact role of PDGFRβ in OS pathogenesis and development are still lacking. Here we assessed the effects of PDGFRβ on invasive and migratory abilities, such as the epithelial–mesenchymal transition and phosphatidylinositol 3‐kinase (PI3K), Akt and mammalian target of rapamycin (mTOR) pathways in HOS cells. Depleting PDGFRβ resulted in reduced migration of HOS cells in the small interfering RNA duplexes specific for the PDGFRβ group compared with the mock and scramble‐treated groups in Transwell invasion assays. Using wound‐healing assays, we demonstrate the rate of wound healing in the PDGF‐BB‐stimulated group was higher compared with the mock‐treated group. Western blot showed that down‐regulation of PDGFRβ decreased the expression of stromal phenotype markers and phosphorylation pathway proteins (PI3K, AKT and mTOR), but the epithelial phenotype marker was increased in HOS cells. Treating HOS cells with PDGF‐BB revealed a treatment time‐dependent increase of phosphorylated, but not total, PI3K, AKT and mTOR. Taken together, we suggest that PDGFRβ plays an important role in OS invasion, migration and epithelial–mesenchymal transition by influencing the PI3K, Akt and mTOR pathways, hence highlighting PDGFRβ as a potential therapeutic target for OS.

Deep Sequencing of Small RNAs from Neurosurgical Extracellular Vesicles Substantiates miR-486-3p as a Circulating Biomarker that Distinguishes Glioblastoma from Lower-Grade Astrocytoma Patients

Extracellular vesicles (EVs) play key roles in glioblastoma (GBM; astrocytoma grade IV) biology and are novel sources of biomarkers. EVs released from GBM tumors can cross the blood-brain-barrier into the periphery carrying GBM molecules, including small non-coding RNA (sncRNA). Biomarkers cargoed in circulating EVs have shown great promise for assessing the molecular state of brain tumors in situ. Neurosurgical aspirate fluids captured during tumor resections are a rich source of GBM-EVs isolated directly from tumor microenvironments. Using density gradient ultracentrifugation, EVs were purified from cavitron ultrasonic surgical aspirate (CUSA) washings from GBM (n = 12) and astrocytoma II-III (GII-III, n = 5) surgeries. The sncRNA contents of surgically captured EVs were profiled using the Illumina^® NextSeq^TM 500 NGS System. Differential expression analysis identified 27 miRNA and 10 piRNA species in GBM relative to GII-III CUSA-EVs. Resolved CUSA-EV sncRNAs could discriminate serum-EV sncRNA profiles from GBM and GII-III patients and healthy controls and 14 miRNAs (including miR-486-3p and miR-106b-3p) and cancer-associated piRNAs (piR_016658, _016659, _020829 and _204090) were also significantly expressed in serum-EVs. Circulating EV markers that correlate with histological, neuroradiographic and clinical parameters will provide objective measures of tumor activity and improve the accuracy of GBM tumor surveillance.

MicroRNAs signatures, bioinformatics analysis of miRNAs, miRNA mimics and antagonists, and miRNA therapeutics in osteosarcoma

MicroRNAs (miRNAs) involved in key signaling pathways and aggressive phenotypes of osteosarcoma (OS) was discussed, including PI3K/AKT/MTOR, MTOR AND RAF-1 signaling, tumor suppressor P53- linked miRNAs, NOTCH- related miRNAs, miRNA -15/16 cluster, apoptosis related miRNAs, invasion-metastasis-related miRNAs, and 14Q32-associated miRNAs cluster. Herrin, we discussed insights into the targeted therapies including miRNAs (i.e., tumor-suppressive miRNAs and oncomiRNAs). Using bioinformatics tools, the interaction network of all OS-associated miRNAs and their targets was also depicted.

miR‑10a increases the cisplatin resistance of lung adenocarcinoma circulating tumor cells via targeting PIK3CA in the PI3K/Akt pathway

Circulating tumor cells (CTCs) that are shed from the primary tumor invade the blood stream or surrounding parenchyma to form new tumors. The present study aimed to explore the underlying mechanism of cisplatin resistance in lung adenocarcinoma CTCs and provide clinical treatment guidance for lung cancer treatment. CTCs from the blood samples of 6 lung adenocarcinoma patients were treated with different concentrations of cisplatin along with A549 and H1299 cells. The sensitivity of CTCs to cisplatin was explored by detecting the inhibitory rate via CCK‑8 assay. The related molecular mechanism was investigated by western blot analysis. miR‑10a expression was detected using quantitative real‑time PCR (RT‑qPCR). The relationship between miR‑10a and phosphatidylinositol‑4,5‑bisphosphate 3‑kinase catalytic subunit α (PIK3CA) was verified and further confirmed by luciferase reporter assay, western blotting and RT‑qPCR assay. The results revealed that CTCs exhibited lower cisplatin sensitivity than A549 and H1299 cells. Moreover, CTCs treated with cisplatin demonstrated higher miR‑10a expression and lower PIK3CA expression than that in A549 and H1299 cells (P<0.01). Expression of phosphoinositide 3‑kinase (PI3K) and protein kinase B (Akt) phosphorylation were also decreased in A549 and H1299 cells compared with CTCs after cisplatin treatment. PIK3CA is a target of miR‑10a, and both miR‑10a overexpression and PIK3CA knockdown obviously decreased the sensitivity of A549 and H1299 cells to cisplatin as well as the expression of PI3K and phosphorylation of Akt. PIK3CA overexpression attenuated the cisplatin resistance of A549 and H1299 cells induced by miR‑10a. In conclusion, miR‑10a suppressed the PI3K/Akt pathway to strengthen the resistance of CTCs to cisplatin via targeting PIK3CA, providing a new therapeutic target for lung cancer treatment.

MK2206 Enhances Cisplatin-Induced Cytotoxicity and Apoptosis in Testicular Cancer Through Akt Signaling Pathway Inhibition

OBJECTIVE

To improve conventional chemotherapeutic efficacy, it is significant to identify novel molecular markers for chemosensitivity as well as possible molecules accelerating cell-killing mechanisms. In this study, we attempted to elucidate how MK2206, an allosteric Akt inhibitor, enhances the cisplatin (CDDP)-induced cytotoxicity and apoptosis in testicular cancer.

MATERIALS AND METHODS

We checked three testicular cancer cell lines for the expression of phospho(p)-Akt and its downstream molecules targets by Western blot. The potential antitumor effects were analyzed by MTT assay in vitro and by subcutaneous xenograft models in vivo. The cell invasion was analyzed by transwell invasion assay, and the activities of Akt signaling pathway and expression of apoptosis-related proteins were measured by Western blot.

RESULTS

Our results indicated that there was overactivation of p-Akt and its downstream molecules in testicular cancer cell lines compared with normal testis epithelium cells. MK2206 (600 nM) inhibited cell invasion in TCAM-2 and P19 cell lines and significantly increased the susceptibility of testicular cancer to CDDP. Combined with CDDP, MK2206 potentiated CDDP-induced cytotoxicity and apoptosis, with repressed expression of p-Akt and its downstream targets. The subcutaneous xenograft models also showed that a combined CDDP/MK2206 therapy completely suppressed tumor growth without any side effects.

CONCLUSION

These results suggested that the concomitant use of MK2206 could enhance the CDDP-induced cytotoxicity and apoptosis in testicular cancer with the suppressed expression of Akt pathway.

Effect of simulated microgravity and ionizing radiation on expression profiles of miRNA, lncRNA, and mRNA in human lymphoblastoid cells

In space, multiple unique environmental factors, particularly microgravity and space radiation, pose a constant threat to astronaut health. MicroRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are functional RNAs that play critical roles in regulating multiple cellular processes. To gain insight into the role of non-coding RNAs in response to radiation and microgravity, we analyzed RNA expression profiles in human lymphoblastoid TK6 cells incubated for 24 h under static or rotating conditions to stimulate microgravity in space, after 2-Gy γ-ray irradiation. The expression of 14 lncRNAs and 17 mRNAs (differentially-expressed genes, DEGs) was found to be significantly downregulated under simulated microgravity conditions. In contrast, irradiation upregulated 55 lncRNAs and 56 DEGs, whereas only one lncRNA, but no DEGs, was downregulated. Furthermore, two miRNAs, 70 lncRNAs, and 87 DEGs showed significantly altered expression in response to simulated microgravity after irradiation, and these changes were independently induced by irradiation and simulated microgravity. GO enrichment and KEGG pathway analyses indicated that the associated target genes showed similar patterns to the noncoding RNAs and were suggested to be involved in the immune/inflammatory response including LPS/TLR, TNF, and NF-κB signaling pathways. However, synergistic effects on RNA expression and cellular responses were also observed with a combination of simulated microgravity and irradiation based on microarray and RT-PCR analysis. Together, our results indicate that simulated microgravity and irradiation additively alter expression patterns but synergistically modulate the expression levels of RNAs and their target genes in human lymphoblastoid 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.

Oroxin B Induces Apoptosis by Down-Regulating MicroRNA-221 Resulting in the Inactivation of the PTEN/PI3K/AKT Pathway in Liver Cancer

This study aims to investigate the anticancer effect of Oroxin B (OB) both in vitro and in vivo, and the molecular mechanism involved in microRNA-221 and the PI3K/Akt/PTEN pathway through modulation of apoptosis in Hepatocellular carcinoma (HCC). DEN-induced rats and HepG2 cells based on the microfluidic chip were employed, while the mRNA and protein expression of microRNA-221, PI3K, p-Akt and PTEN were evaluated by RT-PCR and Western blot analysis. Based on Microfluidic Chip and DEN-induced rat model, OB effectively exerts anti-liver cancer effect both in vitro and in vivo, and the expression of miR-221 in OB treated groups was significantly lower than that in the control group (** p < 0.01). The RT-PCR and Western blot results suggested the PI3K mRNA and protein in OB treated groups were both lower than those in control group and indicated the overexpression of PTEN. Therefore, OB effectively exerts anticancer effects by positively regulating the PTEN gene and then inactivating the PI3K/Akt signaling pathway through down-regulating the expression of the microRNA-221, thereby inducing apoptosis of liver cancer cells. This study offers a theoretical evidence for further development and clinical guidance of OB as an anti-tumor agent.

K-RasG12V/Y40C-PI3K/AKT pathway regulates H1.4S35ph through PKA to promote the occurrence and development of osteosarcoma cancer

Background: Osteosarcoma is prevalent in children and adolescents. H1.4 modification is involved in various types of cancers. Ras pathway is often activated in human cancers. Herein, we explored the effects of Ras pathway through H1.4^S35ph. Methods: Osteosarcoma cancer cell line MG-63 was transfected with Ras gene with G12V and Y40C site mutation. The phosphorylation of H1.4^S35 and AKT was detected by Western blot. Cell viability, cell colonies and migration were analyzed by MTT assay, soft-agar colony formation assay and Transwell assay, respectively. The expression of Ras pathway downstream factors and PKA was detected by qRT-PCR. The relationship between Ras and downstream factors was detected by ChIP. The cell cycle progression was measured by flow cytometry. Results: Transfection with Ras^G12V/Y40C decreased H1.4^S35ph expression while switched on p-AKT^Ser473. Ras^G12V/Y40C increased cell viability, colony numbers and migration while H1.4^S35E (H1.4^S35ph overexpression) led to the opposite results. The regulation of Ras^G12V/Y40C and H1.4^S35E on Ras downstream factors was contrary to each other. Results demonstrated a positive relationship between PKA with H1.4^S35ph with Ras^G12V/Y40C down-regulated both. However, PKA and MDM2 revealed negative regulation with Ras^G12V/Y40C transfection up-regulated MDM2. Conclusion: Ras^G12V/Y40C-PI3K/AKT signal pathway decreased H1.4^S35ph through down-regulation of PKA while up-regulation of MDM2 in MG-63 cells. Highlights H1.4^S35ph is regulated by K-Ras^G12V/Y40-PI3K/AKT in MG-63 cells; Overexpression of H1.4^S35ph regulates MG-63 cell growth; H1.4^S35ph regulates Ras downstream factors; K-Ras^G12V/Y40C-PI3K/AKT activity induces PKA degradation to down-regulate H1.4^S35ph; K-Ras^G12V/Y40C-PI3K/AKT activity involves in PKA degradation via MDM2.

COX‑2 promotes epithelial‑mesenchymal transition and migration in osteosarcoma MG‑63 cells via PI3K/AKT/NF‑κB signaling

The present study aimed to investigate the mechanism by which cyclooxygenase-2 (COX-2) promotes the metastasis of MG-63 osteosarcoma cells through the PI3K/AKT/NF-κB pathway. To achieve this, a recombinant lentivirus containing the COX-2 gene was constructed in order to overexpress COX-2; a recombinant lentivirus containing a control sequence was also constructed. A Transwell chamber migration assay was performed to quantify the migration of the COX-2-transduced cells, and of cells treated with a COX-2 inhibitor (NS398) or a PI3K inhibitor (LY294002). Immunofluorescence assays were performed to determine changes in E-cadherin, vimentin and NF-κB expression levels. ELISAs were performed to quantify the levels of matrix metallopeptidase (MMP)-2, MMP-9 and vascular endothelial growth factor (VEGF) in the culture medium. Western blot analysis was conducted to measure the protein expression levels of MMP-2, MMP-9, PI3K, phosphorylated (p-) PI3K, AKT, p-AKT, inhibitor of NF-κΒ kinase (IKK) and p-IKK. The results demonstrated that the migration ability of the COX-2-overexpressing MG-63 cells was significantly increased compared with the control cells. The migration ability of cells treated with NS398 or LY294002 was significantly decreased. Compared with the control cells, E-cadherin expression was significantly decreased in COX-2-overexpressing cells, while the expression levels of vimentin, MMP-2, MMP-9, VEGF, p-PI3K, p-AKT and p-IKK were significantly increased. Compared with the control cells, E-cadherin expression was significantly increased in cells treated with NS398 or LY294002, while the expression levels of vimentin, MMP-2, MMP-9, VEGF, p-PI3K, p-AKT, and p-IKK were significantly decreased. The total protein levels of PI3K, AKT and IKK were not changed among the treatment groups. In summary, COX-2 overexpression decreased the expression levels of the epithelial protein E-cadherin and increased the expression levels of the mesenchymal proteins vimentin, MMP-2 and MMP-9, as well as promoted cell migration, by activating the PI3K/AKT/NF-κB signaling pathway.

MicroRNA-221 promotes cisplatin resistance in osteosarcoma cells by targeting PPP2R2A

Osteosarcoma (OS), the most common malignant bone tumor, is the main cause of cancer-related deaths in children and young adults. Despite the combination of surgery and multi-agent chemotherapy, patients with OS who develop resistance to chemotherapy or experience recurrence have a dismal prognosis. MicroRNAs (miRNAs) are a class of small noncoding RNAs that repress their targets by binding to the 3′-UTR and/or coding sequences, leading to the inhibition of gene expression. miR-221 is found to be up-regulated in tumors when compared with their matched normal osteoblast tissues. We also observed significant miR-221 up-regulation in the OS cell lines, MG-63, SaoS-2, and U2OS, when compared with the normal osteoblast cell line, HOb. Overexpression of miR-221 promoted OS cell invasion, migration, proliferation, and cisplatin resistance. MG-63 and SaoS-2 cells transfected with miR-221 mimics were more resistant to cisplatin. The IC₅₀ of MG-63 cells transfected with control mimics was 1.24 μM. However, the IC₅₀ of MG-63 cells overexpressing miR-221 increased to 7.65 μM. Similar results were found in SaoS-2 cells, where the IC₅₀ for cisplatin increased from 3.65 to 8.73 μM. Thus, we report that miR-221 directly targets PP2A subunit B (PPP2R2A) in OS by binding to the 3′-UTR of the PPP2R2A mRNA. Restoration of PPP2R2A in miR-221-overexpressing OS cells recovers the cisplatin sensitivity of OS cells. Therefore, the present study suggests a new therapeutic approach by inhibiting miR-221 for anti-chemoresistance in OS.

Upregulation of microRNA-7 contributes to inhibition of the growth and metastasis of osteosarcoma cells through the inhibition of IGF1R

We aim to uncover the methylation of microRNA-7 (miR-7) promoter in osteosarcoma (OS) and the inner mechanism of miR-7 on the progression of OS cells. Expression and methylation state of miR-7 in OS tissues and cells were detected. With the aim to unearth the ability of miR-7 in OS, the proliferation, cell cycle progression, apoptosis, invasion, migration of OS cells, and the tumor growth in nude mice were determined. Meanwhile, IGF1R expression was detected and the association between miR-7 and IGF1R was confirmed. The proliferating cell nuclear antigen (PCNA) expression was tested by immunohistochemical staining, and the lung metastasis was observed by H&E staining. miR-7 expression was decreased and methylation state of miR-7 was increased in OS tissues and cells. Upregulated miR-7 inhibited proliferation, cell cycle progression, invasion,and migration, while inducing apoptosis of OS cells and the tumor growth as well as PCNA expression in nude mice. Expression of IGF1R was downregulated in OS cells with overexpression of miR-7. Experiments verified the binding site between miR-7 and IGF1R. Our study demonstrates that abnormal methylation of miR-7 contributes to decreased miR-7 in OS. In addition, miR-7 represses the initiation and progression of OS cells through the inhibition of IGF1R.

Velvet Antler compounds targeting major cell signaling pathways in osteosarcoma - a new insight into mediating the process of invasion and metastasis in OS

Velvet antler is the only renewable bone tissue of mammalian animals, which consists of a variety of growth factors, amino acids and polypeptides. But the mechanism of high-speed proliferation without carcinogenesis is still mystifying. The previous study of this work found that the velvet antler peptides (VAP) could not only inhibit the proliferation and migration of osteosarcoma cell lines MG-63 and U2OS, but also induced U2OS apoptosis and inhibited MG-63 epithelial-mesenchymal transition (EMT) through TGF-β and Notch pathways. These results lead us to conclude that VAP has the potential ability to mediate osteosarcoma cells by regulating related signaling pathways and growth factors. Therefore, finding a new appropriate inhibitor for OS is a valuable research direction, which will give patients a better chance to receive proper therapy. From an applied perspective, this review summarized the effects of velvet antler, genes, growth factors and research progress of relative pathways and genes of osteosarcoma, which are poised to help link regenerative molecular biology and regenerative medicine in osteosarcoma pathogenesis.

Drug resistance-related microRNAs in osteosarcoma: Translating basic evidence into therapeutic strategies

Although the application of multiple chemotherapy brought revolutionary changes to improve overall survival of osteosarcoma patients, the existence of multidrug resistance (MDR) has become a great challenge for successful osteosarcoma treatment in recent decades. Substantial studies have revealed various underlying mechanisms of MDR in cancers. As for osteosarcoma, evidence has highlighted that microRNAs (miRNAs) can mediate in the processes of DNA damage response, apoptosis avoidance, autophagy induction, activation of cancer stem cells, and signal transduction. Besides, these drug resistance‐related miRNAs showed much promise for serving as candidates for predictive biomarkers of poor outcomes and shorter survival time, and therapeutic targets to reverse drug resistance and overcome treatment refractoriness. This review aims to demonstrate the potential molecular mechanisms of miRNAs‐regulated drug resistance in osteosarcoma, and provide insight in translating basic evidence into therapeutic strategies.