Targeted MEK inhibition by cobimetinib enhances doxorubicin's efficacy in osteosarcoma models

Targeting nerve growth factor-mediated osteosarcoma metastasis: mechanistic insights and therapeutic opportunities using larotrectinib

Osteosarcoma (OS) therapy presents numerous challenges, due largely to a low survival rate following metastasis onset. Nerve growth factor (NGF) has been implicated in the metastasis and progression of various cancers; however, the mechanism by which NGF promotes metastasis in osteosarcoma has yet to be elucidated. This study investigated the influence of NGF on the migration and metastasis of osteosarcoma patients (88 cases) as well as the underlying molecular mechanisms, based on RNA-sequencing and gene expression data from a public database (TARGET-OS). In osteosarcoma patients, the expression of NGF was significantly higher than that of other growth factors. This observation was confirmed in bone tissue arrays from 91 osteosarcoma patients, in which the expression levels of NGF and matrix metallopeptidase-2 (MMP-2) protein were significantly higher than in normal bone, and strongly correlated with tumor stage. In summary, NGF is positively correlated with MMP-2 in human osteosarcoma tissue and NGF promotes osteosarcoma cell metastasis by upregulating MMP-2 expression. In cellular experiments using human osteosarcoma cells (143B and MG63), NGF upregulated MMP-2 expression and promoted wound healing, cell migration, and cell invasion. Pre-treatment with MEK and ERK inhibitors or siRNA attenuated the effects of NGF on cell migration and invasion. Stimulation with NGF was shown to promote phosphorylation along the MEK/ERK signaling pathway and decrease the expression of microRNA-92a-1-5p (miR-92a-1-5p). In in vivo experiments involving an orthotopic mouse model, the overexpression of NGF enhanced the effects of NGF on lung metastasis. Note that larotrectinib (a tropomyosin kinase receptor) strongly inhibited the effect of NGF on lung metastasis. In conclusion, it appears that NGF promotes MMP-2-dependent cell migration by inhibiting the effects of miR-92a-1-5p via the MEK/ERK signaling cascade. Larotrectinib emerged as a potential drug for the treatment of NGF-mediated metastasis in osteosarcoma.

Potential drug-drug interactions with mitogen-activated protein kinase (MEK) inhibitors used to treat melanoma

INTRODUCTION

The management of patients with BRAF-mutated advanced melanoma who are undergoing targeted therapy with MEK inhibitors can be complicated by the co-administration of multiple medications, which can give rise to drug-drug interactions of clinical significance.

COVERED AREAS

Our review presents a comprehensive analysis of the pharmacokinetic and pharmacodynamic interactions of the three approved for advanced melanoma MEK inhibitor drugs - binimetinib, cobimetinib, and trametinib. MEDLINE (PubMed) was utilized for the literature search, comprising clinical studies, observational studies, and preclinical research. The review discusses the impact of these interactions on efficacy and safety of the treatments and differentiates between interactions supported by pharmacokinetic or pharmacodynamic mechanisms, those encountered in clinical practice, and those observed in preclinical studies.

EXPERT OPINION

Physicians should be aware about potential benefits, but also increased toxicity caused by drug interactions between MEK inhibitors and other drugs in the management of patients with metastatic melanoma.

Designing of kinase hinge binders: A medicinal chemistry perspective

Protein kinases are key regulators of cellular signaling and play a critical role in oncogenesis. Inhibitors of protein kinases are pursued by both industry and academia as a promising target for cancer therapy. Within the protein kinases, the ATP site has produced more than 40 FDA-approved drugs. The ATP site is broadly composed of a hinge region, gatekeeper residues, DFG-loop, ribose pocket, and other hydrophobic regions. The hinge region in the ATP site can be used for designing potent inhibitors. In this review, we discuss some representative studies that will highlight the interactions of heterocyclic compounds with hinge regions of different kinases like BRAF kinase, EGRF kinase, MAP kinase, and Mps1 kinase.

The roles of glycolysis in osteosarcoma

Metabolic reprogramming is of great significance in the progression of various cancers and is critical for cancer progression, diagnosis, and treatment. Cellular metabolic pathways mainly include glycolysis, fat metabolism, glutamine decomposition, and oxidative phosphorylation. In cancer cells, reprogramming metabolic pathways is used to meet the massive energy requirement for tumorigenesis and development. Metabolisms are also altered in malignant osteosarcoma (OS) cells. Among reprogrammed metabolisms, alterations in aerobic glycolysis are key to the massive biosynthesis and energy demands of OS cells to sustain their growth and metastasis. Numerous studies have demonstrated that compared to normal cells, glycolysis in OS cells under aerobic conditions is substantially enhanced to promote malignant behaviors such as proliferation, invasion, metastasis, and drug resistance of OS. Glycolysis in OS is closely related to various oncogenes and tumor suppressor genes, and numerous signaling pathways have been reported to be involved in the regulation of glycolysis. In recent years, a vast number of inhibitors and natural products have been discovered to inhibit OS progression by targeting glycolysis-related proteins. These potential inhibitors and natural products may be ideal candidates for the treatment of osteosarcoma following hundreds of preclinical and clinical trials. In this article, we explore key pathways, glycolysis enzymes, non-coding RNAs, inhibitors, and natural products regulating aerobic glycolysis in OS cells to gain a deeper understanding of the relationship between glycolysis and the progression of OS and discover novel therapeutic approaches targeting glycolytic metabolism in OS.

Cobimetinib Sensitizes Cervical Cancer to Paclitaxel via Suppressing Paclitaxel-Induced ERK Activation

<b><i>Introduction:</i></b> Chemoresistance remains the main cause of treatment failure in cervical cancer and novel therapeutic strategies are required. Cobimetinib, a potent yet selective inhibitor of MEK1 and 2, is currently used to treat melanoma clinically. In this work, we identified cobimetinib as a promising candidate for treating cervical cancer. <b><i>Methods:</i></b> The in vitro and in vivo efficacies of cobimetinib were examined using cervical cancer cell cultures and xenograft mouse model. Its combination with paclitaxel was analyzed using the combination index. Immunoblotting was performed on MAPK and ERK pathways. <b><i>Results:</i></b> Cobimetinib displays a potent anti-cervical cancer activity in a panel of cell lines regardless of cellular origin and HPV presence, and its combination with paclitaxel is synergistic in inhibiting cervical cancer cells. This is achieved by the growth inhibition and caspase-dependent apoptosis induction, through inhibiting MAPK/ERK activation. In addition, paclitaxel activates ERK in cervical cancer cells, and this can be reversed by cobimetinib. We finally confirm the efficacy of cobimetinib alone and its combination with paclitaxel in the cervical cancer xenograft mouse model. <b><i>Discussion/Conclusion:</i></b> Our preclinical findings will accelerate the initialization of clinical trials to use combination of cobimetinib and paclitaxel for treating cervical cancer. Our work also emphasizes the therapeutic value of targeting MAPK/ERK to overcome chemoresistance in cervical cancer.

Biglycan Interacts with Type I Insulin-like Receptor (IGF-IR) Signaling Pathway to Regulate Osteosarcoma Cell Growth and Response to Chemotherapy

Simple Summary

Osteosarcoma (OS) is an aggressive, primary bone cancer. OS cells produce altered osteoid whose components participate in signaling correlated to the development of this cancer. Biglycan (BGN), a proteoglycan, is correlated to aggressive OS type and resistance to chemotherapy. A constitutive signaling of insulin-like growth factor receptor I (IGF-IR) signaling in sarcoma progression was established. We showed that biglycan binds IGF-IR resulting in prolonged IGF-IR activation, nuclear translocation, and growth response of the poorly-differentiated MG63 cells correlated to increased aggressiveness markers expression and enhanced chemoresistance. This mechanism is not valid in moderately and well-differentiated, biglycan non-expressing U-2OS and Saos-2 OS cells.

Abstract

Osteosarcoma (OS) is a mesenchymally derived, aggressive bone cancer. OS cells produce an aberrant nonmineralized or partly mineralized extracellular matrix (ECM) whose components participate in signaling pathways connected to specific pathogenic phenotypes of this bone cancer. The expression of biglycan (BGN), a secreted small leucine-rich proteoglycan (SLRP), is correlated to aggressive OS phenotype and resistance to chemotherapy. A constitutive signaling of IGF-IR signaling input in sarcoma progression has been established. Here, we show that biglycan activates the IGF-IR signaling pathway to promote MG63 biglycan-secreting OS cell growth by forming a complex with the receptor. Computational models of IGF-IR and biglycan docking suggest that biglycan binds IGF-IR dimer via its concave surface. Our binding free energy calculations indicate the formation of a stable complex. Biglycan binding results in prolonged IGF-IR activation leading to protracted IGF-IR-dependent cell growth response of the poorly-differentiated MG63 cells. Moreover, biglycan facilitates the internalization (p ≤ 0.01, p ≤ 0.001) and sumoylation-enhanced nuclear translocation of IGF-IR (p ≤ 0.05) and its DNA binding in MG63 cells (p ≤ 0.001). The tyrosine kinase activity of the receptor mediates this mechanism. Furthermore, biglycan downregulates the expression of the tumor-suppressor gene, PTEN (p ≤ 0.01), and increases the expression of endothelial–mesenchymal transition (EMT) and aggressiveness markers vimentin (p ≤ 0.01) and fibronectin (p ≤ 0.01) in MG63 cells. Interestingly, this mechanism is not valid in moderately and well-differentiated, biglycan non-expressing U-2OS and Saos-2 OS cells. Furthermore, biglycan exhibits protective effects against the chemotherapeutic drug, doxorubicin, in MG63 OS cells (p ≤ 0.01). In conclusion, these data indicate a potential direct and adjunct therapeutical role of biglycan in osteosarcoma.

MALAT-1 is Associated with the Doxorubicin Resistance in U-2OS Osteosarcoma Cells

Purpose

Our study aimed to investigate the relationship between MALAT-1 (metastasis-associated lung adenocarcinoma transcript 1) expression and the chemotherapy drug resistance in osteosarcoma.

Methods

The U-2OS osteosarcoma cell line was selected for the experiment. The cells were treated with methotrexate, doxorubicin, cisplatin, and ifosfamide, respectively. RT-PCR was applied to detect the MALAT-1 expression in cells. The doxorubicin-resistant cell line was constructed. The cells were divided into doxorubicin-sensitivity group (DS/shCtrl), doxorubicin-resistance group (DR/shCtrl) and shMALAT1-doxorubicin-resistance group (DR/shMALAT1). The colony formation assay and 5-ethynyl-2ʹ-deoxyuridine (EdU) assay were used to detect cell proliferation. PI staining was used to detect the cell cycle. Transwell assay and wound healing assay were used to observe the migration and invasion ability. Annexin V-FITC assay was used to detect cell apoptosis. Western blot was used to detect the protein expression and potential mechanism. The impacts of MALAT-1 expression were verified in vivo.

Results

The MALAT-1 was upregulated in the doxorubicin-resistant U-2OS osteosarcoma cells. Downregulating MALAT-1 in the doxorubicin-resistant cells inhibited the proliferation, migration, and invasiveness, increased the ratio of cells in the G0/G1 phase, promoted apoptosis. In the doxorubicin-resistant U-2OS cells, the extracellular regulated protein kinases (ERK) phosphorylation was declined, which could be reversed by downregulating MALAT-1. In vivo assay indicated that the growth of doxorubicin-resistant solid osteosarcoma could be suppressed by downregulating MALAT-1.

Conclusion

Our study provides evidence that doxorubicin may upregulate MALAT-1 in osteosarcoma. Downregulating MALAT-1 in the doxorubicin resistance U-2OS cells could reverse the resistance and may improve chemotherapeutic efficiency. Some conclusions in previous literature may be one-sided.

Application of tumor-targeting peptide-decorated polypeptide nanoparticles with doxorubicin to treat osteosarcoma

Osteosarcoma is the most common primary malignant bone tumor in childhood and adolescence. Currently, surgery combined with chemotherapy is the main treatment for osteosarcoma. However, the long-term survival of patients with metastatic osteosarcoma is unsatisfactory. Therefore, new treatment methods to improve the prognosis of patients with osteosarcoma are required. The present study aimed to develop nanocarriers with both tumor targeting and reduction responsiveness abilities, and to improve the therapeutic effect and reduce toxicity by loading traditional small molecule antitumor drugs. The tumor targeting peptide-decorated, doxorubicin (DOX)-loaded mPEG-P(Phe-co-Cys) nanoparticles were developed successfully through the ring-opening polymerization of amino acids. The peptide VATANST (STP) can specifically bind with vimentin, which is highly expressed on the osteosarcoma cell surface, resulting in tumor targeting effects. The nanoparticle is core–shell structured to protect the loaded DOX during blood flow. The disulfide bonds within the nanoparticles are sensitive to the osteosarcoma microenvironment, which has high glutathione (GSH) levels. Under the enhanced permeability and retention and active tumor targeting effects, the STP-decorated DOX-loaded nanoparticles accumulated in tumor tissues. High GSH levels can rupture disulfide bonds, resulting in the controlled release of DOX, which will cause necrosis of tumor cells. The characteristics of the synthesized nanoparticles, DOX release profiles in vitro and in vivo, cytotoxicity analysis, animal study, and safety evaluation were performed. The nanoparticles could increase the tumor inhibition efficiency against osteosarcoma and reduce the side effects of DOX to major organs. The STP-decorated mPEG-P(Phe-co-Cys) nanoparticles might be a suitable drug delivery system for DOX to treat osteosarcoma.

Chlorogenic Acid Enhances Doxorubicin-Mediated Cytotoxic Effect in Osteosarcoma Cells

Despite the recurring outbreak of resistance mechanisms and adverse reactions, doxorubicin (Doxo) still remains the standard-of-care for several cancers, including osteosarcoma (OS). As an appealing source of phytochemical compounds, naturally occurring molecules have extensively been reported to overcome Doxo limitations in preclinical models. Unlike other dietary polyphenols, only few studies recognize chlorogenic acid (CGA) as a potential partner in combination therapy, while, conversely, its anticancer evidence is steadily growing, ultimately in OS. On this basis, herein we examine the cooperating effects between CGA and Doxo in U2OS and MG-63 human OS cells. With respect to Doxo alone, the concomitant administration of CGA further decreased cell viability and growth, promoting cell death potentially via apoptosis induction. Furthermore, a longer-lasting reduction in clonogenic potential deeply supported the CGA ability to improve Doxo efficacy in those cells. Remarkably, CGA treatment ameliorated Doxo-induced cytotoxicity in H9c2 rat cardiomyocyte cells instead. Although inactivation of p44/42 MAPK was detected in response to CGA plus Doxo, PD98059-mediated p44/42 MAPK impairment enhanced the combination outcome in OS cells. These findings firstly propose CGA as a promising chemosensitizer and cardioprotective agent in OS therapy, suggesting the p44/42 MAPK pathway as relevantly involved in CGA-mediated Doxo susceptibility.

Preclinical activity of cobimetinib alone or in combination with chemotherapy and targeted therapies in renal cell carcinoma

Background: The poor outcome of advanced renal cell carcinoma (RCC) necessitates new treatments. Cobimetinib is a MEK inhibitor and approved for the treatment of melanoma. This work investigated the efficacy of cobimetinib alone and in combination with anti-RCC drugs. Methods: Proliferation and apoptosis assays were performed, and combination index was analyzed on RCC cell lines (CaKi-2, 786-O, A-704, ACHN and A489) and xenograft models. Immunoblotting analysis was conducted to investigate the MAPK pathway. Results: Cobimetinib was active against RCC cells, with IC₅₀ at 0.006-0.8μM, and acted synergistically with standard-of-care therapy. Cobimetinib at nontoxic doses prevented tumor formation, inhibited tumor growth and enhanced efficacy of 5-fluorouracil, sorafenib and sunitinib via suppressing Raf/MEK/ERK, leading to MAPK pathway inhibition. Conclusion: Our findings demonstrate the potent anti-RCC activity of cobimetinib and its synergism with RCC standard-of-care drugs, and confirm the underlying mechanism of the action of cobimetinib.