Combination Treatment With Sorafenib and Everolimus Regresses a Doxorubicin-resistant Osteosarcoma in a PDOX Mouse Model

Efficacy and safety of sorafenib in adult metastatic osteosarcoma patients

BACKGROUND

There are limited data on the efficacy of targeted therapy in metastatic osteosarcoma. The goal of this study was to assess the effectiveness of sorafenib in adult patients with heavily pretreated metastatic osteosarcoma.

METHOD

Patients with metastatic osteosarcoma aged more than 18 years were assessed retrospectively. The patients' clinical, pathological, and therapeutic data were collected. For survival analysis, Kaplan-Meier models were used.

RESULTS

The research involved 15 patients. The ratio of male and female patients was 2/1, with a median age of 25 years (range: 19-64 years). The most common primary tumor localization was the extremities (66.6%). Fourteen (93.3%) patients had previously received palliative chemotherapy and six (40%) patients had palliative radiotherapy. The median progression-free survival was found as 5.5 months (95% confidence interval, 1.3-9.7). A stable response was observed in seven (46.6%) patients and progressive disease in eight (53.4%) patients. Grade 1-2 toxicities were detected in 50% of the patients, while grade 3-4 toxicities were observed in 14.3% of the patients.

CONCLUSIONS

We demonstrated real-life results of sorafenib for disease management in pretreated adult patients with metastatic osteosarcoma in the study. Sorafenib was effective for disease control and well tolerated in the patients. Sorafenib may be a treatment option for disease control after the disease progresses with chemotherapy in patients with metastatic osteosarcoma.

Targeting signaling pathways in osteosarcoma: Mechanisms and clinical studies

Osteosarcoma (OS) is a highly prevalent bone malignancy among adolescents, accounting for 40% of all primary malignant bone tumors. Neoadjuvant chemotherapy combined with limb-preserving surgery has effectively reduced patient disability and mortality, but pulmonary metastases and OS cells' resistance to chemotherapeutic agents are pressing challenges in the clinical management of OS. There has been an urgent need to identify new biomarkers for OS to develop specific targeted therapies. Recently, the continued advancements in genomic analysis have contributed to the identification of clinically significant molecular biomarkers for diagnosing OS, acting as therapeutic targets, and predicting prognosis. Additionally, the contemporary molecular classifications have revealed that the signaling pathways, including Wnt/β-catenin, PI3K/AKT/mTOR, JAK/STAT3, Hippo, Notch, PD-1/PD-L1, MAPK, and NF-κB, have an integral role in OS onset, progression, metastasis, and treatment response. These molecular classifications and biological markers have created new avenues for more accurate OS diagnosis and relevant treatment. We herein present a review of the recent findings for the modulatory role of signaling pathways as possible biological markers and treatment targets for OS. This review also discusses current OS therapeutic approaches, including signaling pathway-based therapies developed over the past decade. Additionally, the review covers the signaling targets involved in the curative effects of traditional Chinese medicines in the context of expression regulation of relevant genes and proteins through the signaling pathways to inhibit OS cell growth. These findings are expected to provide directions for integrating genomic, molecular, and clinical profiles to enhance OS diagnosis and treatment.

Ursonic acid inhibits migration and invasion of human osteosarcoma cells through the suppression of mitogen-activated protein kinases and matrix metalloproteinases

INTRODUCTION

Osteosarcoma (OS) is the most common form of bone malignancy. Although contemporary chemotherapy and surgery have improved the prognosis of those with OS, developing new OS therapies has proven difficult for some time. The activation of the matrix metalloproteinase (MMP) and mitogen-activated protein kinase (MAPK) signaling pathways can induce metastasis, which is an obstacle to OS treatment. Ursonic acid (UNA) is a phytochemical with the potential to cure a variety of human ailments, including cancer.

METHODS AND RESULTS

In this study, we investigated the anti-tumor properties of UNA in MG63 cells. We conducted colony formation assay, wound healing assay, and Boyden chamber assays to investigate the anti-OS effects of UNA. UNA was found to significantly inhibit the proliferative, migratory, and invasive abilities of MG63 cells. This bioactivity of UNA was mediated by the inhibition of extracellular signal-regulated kinase (ERK) and p38 and reduction of MMP-2 transcriptional expression as observed in western blot analysis, gelatin zymography and RT-PCR. Anti-OS activities of UNA were also observed in Saos2 and U2OS cells, indicating that its anti-cancer properties are not specific to cell types.

CONCLUSION

Our findings suggest that UNA has the potential for use in anti-metastatic drugs in the treatment of OS.

Multikinase-Inhibitor Screening in Drug-resistant Osteosarcoma Patient-derived Orthotopic Xenograft Mouse Models Identifies the Clinical Potential of Regorafenib

BACKGROUND/AIM

Osteosarcoma is a recalcitrant heterogenous malignancy. The aim of the present study was to compare a series of multikinase inhibitors (MKIs) for efficacy on two drug-resistant osteosarcoma patient-derived orthotopic xenograft (PDOX) models in order to identify a clinical candidate.

MATERIALS AND METHODS

The two osteosarcoma PDOX models were tested for response to the following MKIs: pazopanib, sunitinib, sorafenib, crizotinib, and regorafenib, in comparison to first-line treatment with cisplatinum and an untreated control.

RESULTS

Regorafenib led to regression of osteosarcoma in both PDOXs. Total necrosis was observed pathologically in the regorafenib-treated tumors. Sorafenib arrested growth, without inducing regression, in one osteosarcoma model but not the other, and the other MKIs only slowed tumor growth.

CONCLUSION

The present study demonstrated that regorafenib is much more effective than the other MKIs tested and has clinical potential against recalcitrant osteosarcoma.

The First Mouse Model of Primary Osteosarcoma of the Breast

BACKGROUND/AIM

Sarcomas of the breast are extremely rare malignant tumors and comprise only 5% of all sarcomas and fewer than 1% of breast cancers. Primary osteosarcoma of the breast is histologically indistinguishable from osteosarcoma of the bone. Effective therapies of this recalcitrant disease have not yet been developed.

MATERIALS AND METHODS

A patient-derived xenograft (PDX) mouse model of primary osteosarcoma of the breast was established by subcutaneous implantation of the surgical specimen, along with surrounding normal tissue. Hematoxylin and eosin (H&E) staining was performed on paraffin-embedded histological sections of the original tumor resected from the patient and from implanted tumors that grew in nude mice.

RESULTS

Tumors grew in 46 of 51 mice implanted with the original surgical specimen. The H&E-stained slides of the mouse-grown tumor and the original patient tumor matched, both showing large areas of spindle-shaped cells, characteristic of osteosarcoma.

CONCLUSION

The first PDX mouse model of primary breast osteosarcoma was established which will enable testing of novel therapeutics as well as basic research of osteosarcoma of the breast.

A Novel Procedure for Orthotopic Tibia Implantation for Establishment of a More Clinical Osteosarcoma PDOX Mouse Model

BACKGROUND/AIM

Osteosarcoma is a rare type of malignancy that affects mostly children and adolescents. A new procedure was designed to create an improved patient-derived orthotopic xenograft (PDOX) mouse model of osteosarcoma that more closely mimics osteosarcoma in clinical settings. Previous osteosarcoma PDOX models involved implanting a tumor fragment near the femur of nude mice in a space created by separating muscle.

MATERIALS AND METHODS

A hole was created in the tibia of nude mice and an osteosarcoma tumor fragment was implanted directly into the bone.

RESULTS

This procedure resulted in tumor growth in the bone similar to osteosarcoma tumors found in clinical patients.

CONCLUSION

The establishment ratio for this procedure is 80% making it a practical and clinically-relevant model for screening effective therapies for osteosarcoma patients.

EPHA2 Promotes the Invasion and Migration of Human Tongue Squamous Cell Carcinoma Cal-27 Cells by Enhancing AKT/mTOR Signaling Pathway

EPHA2 is a member of the ephrin receptor tyrosine kinase family and is closely related to the malignant tumor progression. The effect of EPHA2 on OSCC is not clear. This study explored the role of EPHA2 and AKT/mTOR signaling pathways in Cal-27 cell invasion and migration. The expression of EPHA2 and EPHA4 in human OSCC and normal oral tissue was detected by immunohistochemistry. EPHA2-overexpressing and EPHA2-knockdown Cal-27 cells were established, and the cells were treated with an AKT inhibitor (MK2206) and mTOR inhibitor (RAD001). The expression of EPHA2 was detected by qRT-PCR, cell proliferation was evaluated by MTT assay, cell migration and invasion were examined by scratch and Transwell assay, and cell morphology and apoptosis were assessed by Hoechst 33258 staining. Western blot was performed to detect the expression of proteins related to AKT/mTOR signaling, cell cycle, and pseudopod invasion. EPHA2 and EPHA4 were highly expressed in clinical human OSCC. Overexpression of EPHA2 promoted the proliferation, migration, and invasion of Cal-27 cells, inhibited cell cycle blockage and apoptosis, and enhanced the activity of the AKT/mTOR signaling pathway. MK2206 (AKT inhibitor) and RAD001 (mTOR inhibitor) reversed the effect of EPHA2 overexpression on the biological behavior of Cal-27 cells. EPHA2 promotes the invasion and migration of Cal-27 human OSCC cells by enhancing the AKT/mTOR signaling pathway.

A Novel Anionic-phosphate-platinum Complex Effectively Targets a Cisplatinum-resistant Osteosarcoma in a Patient-derived Orthotopic Xenograft Mouse Model

BACKGROUND/AIM

We have previously developed a novel bone-targeting platinum compound, 3Pt, and showed that it has strong inhibitory activity against osteosarcoma cells and orthotopic cell-line xenograft mouse models. In the present report, we compared the efficacy of 3Pt to cisplatinum (CDDP) in a CDDP-resistant relapsed osteosarcoma patient-derived orthotopic xenograft (PDOX) mouse model.

PATIENTS AND METHODS

The tumor of a patient with osteosarcoma of the distal femur was treated with CDDP-based chemotherapy followed by surgery. The surgical specimen was used to establish a PDOX model. An osteosarcoma cell line was also established from the original patient tumor. Osteosarcoma cell viability was assessed with the WST-8 assay and the IC50 values were calculated. The PDOX models were randomized into three groups: untreated control, CDDP-treated group, and 3Pt-treated group. Tumor size and body weight were measured twice a week.

RESULTS

3Pt had a strong concentration-dependent cytocidal effect in vitro. The IC₅₀ value of 3Pt was significantly lower than that of CDDP. On day 14 of the treatment, 3Pt caused a significantly greater tumor growth inhibition compared to the untreated control and CDDP-treated mice.

CONCLUSION

3Pt is a promising clinical candidate for the treatment of recalcitrant osteosarcoma.

microRNA-216b enhances cisplatin-induced apoptosis in osteosarcoma MG63 and SaOS-2 cells by binding to JMJD2C and regulating the HIF1α/HES1 signaling axis

Background

Although cisplatin-based chemotherapy represents the standard regimen for osteosarcoma (OS), OS patients often exhibit treatment failure and poor prognosis due to chemoresistance to cisplatin. Emerging research has highlighted the tumor suppressive properties of microRNAs (miRNAs or miRs) in various human cancers via the inhibition of the histone demethylase jumonji domain containing protein 2C (JMJD2C). As a coactivator for hypoxia-inducible factor 1α (HIF1α), JMJD2C targets hairy and enhancer of split-1 (HES1) gene. Hence, the current study aimed to elucidate the role of miR-216b in OS cell cisplatin resistance to identify the underlying mechanism of miR-216b regulating the JMJD2C//HIF1α/HES1 signaling.

Methods

Tumor and paracancerous tissues were collected from OS patients to determine the expression patterns of miR-216b and JMJD2C. After ectopic expression and knockdown experiments in the OS cells, CCK-8 assay and flow cytometry were employed to determine cell viability and apoptosis. The interaction of miR-216b, JMJD2C, HIF1α and HES1 was subsequently determined by dual luciferase reporter, co-immunoprecipitation (IP) and ChIP-qPCR assays. In vivo experiments were conducted to further verify the role of the miR-216b in the resistance of OS cells to cisplatin.

Results

miR-216b expression was reduced in the OS tissues, as well as the MG63 and SaOS-2 cells. Heightened miR-216b expression was found to be positively correlated with patient survival, and miR-216b further enhanced cisplatin-induced apoptosis of MG63 and SaOS-2 cells. Mechanistically, miR-216b inhibited JMJD2C expression by binding to its 3’UTR. Through interaction with HIF1α, JMJD2C removed the H3K9 methylation modification at the HES1 promoter region, leading to upregulation of HES1 in vitro. Furthermore, miR-216b was observed to increase the tumor growth in nude mice in the presence of cisplatin treatment. HES1 overexpression weakened the effects of miR-216b in MG63 and SaOS-2 cells and in nude mouse xenografts.

Conclusion

Overall, miR-216b enhanced the sensitivity of OS cells to cisplatin via downregulation of the JMJD2C/HIF1α/HES1 signaling axis, highlighting the capacity of miR-216b as an adjunct to cisplatin chemotherapy in the treatment of OS.

PPARγ Agonist Pioglitazone in Combination With Cisplatinum Arrests a Chemotherapy-resistant Osteosarcoma PDOX Model

BACKGROUND/AIM

Cisplatinum (CDDP) is a first-line drug in osteosarcoma treatment and the acquisition of resistance to CDDP is associated with a poor prognosis. Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear hormone receptor that plays important roles in cell proliferation, differentiation, development, metabolism and cell death. Recently, PPARγ was reported to enhance the efficacy, overcome resistance, and decrease the toxicity of CDDP in various human cancers. In this study we tested whether pioglitazone (PIO), a PPARγ agonist, could overcome CDDP resistance in osteosarcoma.

MATERIALS AND METHODS

In this study, we used a human osteosarcoma cell line and a patient-derived orthotopic xenograft (PDOX) models of osteosarcoma. We measured cell viability of 143B human osteosarcoma cells when treated with CDDP and PIO. We randomized PDOX models of osteosarcoma into four treatment groups: Group 1, Untreated control; Group 2, PIO alone; Group 3, CDDP alone; Group 4, a combination of CDDP and PIO. Each group comprised six mice. Mice were treated for 14 days and tumor size and body weight were measured.

RESULTS

Cell viability of 143B human osteosarcoma cells was significantly reduced when PIO (50 μmol/l) was combined with CDDP compared to CDDP alone. PDOX osteosarcoma tumors treated with the CDDP-PIO combination showed the strongest tumor growth inhibition compared to other treatment groups. PDOX osteosarcoma tumors treated with the CDDP-PIO combination had the least cancer cells and the most necrosis in histological section.

CONCLUSION

These results suggest that combining PIO along with CDDP could be an effective treatment strategy for osteosarcoma and has important clinical potential for patients.

ABCA1/ABCB1 Ratio Determines Chemo- and Immune-Sensitivity in Human Osteosarcoma

The ATP Binding Cassette transporter B1 (ABCB1) induces chemoresistance in osteosarcoma, because it effluxes doxorubicin, reducing the intracellular accumulation, toxicity, and immunogenic cell death induced by the drug. The ATP Binding Cassette transporter A1 (ABCA1) effluxes isopentenyl pyrophosphate (IPP), a strong activator of anti-tumor Vγ9Vδ2 T-cells. Recruiting this population may represent an alternative strategy to rescue doxorubicin efficacy in ABCB1-expressing osteosarcoma. In this work, we analyzed how ABCA1 and ABCB1 are regulated in osteosarcoma, and if increasing the ABCA1-dependent activation of Vγ9Vδ2 T-cells could be an effective strategy against ABCB1-expressing osteosarcoma. We used 2D-cultured doxorubicin-sensitive human U-2OS and Saos-2 cells, their doxorubicin-resistant sublines (U-2OS/DX580 and Saos-2/DX580), and 3D cultures of U-2OS and Saos-2 cells. DX580-sublines and 3D cultures had higher levels of ABCB1 and higher resistance to doxorubicin than parental cells. Surprisingly, they had reduced ABCA1 levels, IPP efflux, and Vγ9Vδ2 T-cell-induced killing. In these chemo-immune-resistant cells, the Ras/Akt/mTOR axis inhibits the ABCA1-transcription induced by Liver X Receptor α (LXRα); Ras/ERK1/2/HIF-1α axis up-regulates ABCB1. Targeting the farnesylation of Ras with self-assembling nanoparticles encapsulating zoledronic acid (NZ) simultaneously inhibited both axes. In humanized mice, NZ reduced the growth of chemo-immune-resistant osteosarcomas, increased intratumor necro-apoptosis, and ABCA1/ABCB1 ratio and Vγ9Vδ2 T-cell infiltration. We suggest that the ABCB1^highABCA1^low phenotype is indicative of chemo-immune-resistance. We propose aminobisphosphonates as new chemo-immune-sensitizing tools against drug-resistant osteosarcomas.

Surface engineering of nanoparticles with ligands for targeted delivery to osteosarcoma

Osteosarcoma is one of the most common malignant bone tumors which affect adolescents. Neoadjuvant chemotherapy followed by operation has become recommended for osteosarcoma treatment. Whereas, the effects of conventional chemotherapy are unsatisfactory because of multidrug resistance, fast clearance rate, nontargeted delivery, side effects and so on. Accordingly, Nanoparticle-mediated targeted drug delivery system (NTDDS) is recommended to be a novel treatment strategy for osteosarcoma. NTDDS can overcome the above obstacles by enhanced permeability and retention effect and active targeting. The active targeting of the delivery system is mainly based on ligands. In this study, we investigate and summarize the most common ligands used in the latest NTDDS for osteosarcoma. It might provide new insights into nanomedicine for osteosarcoma treatment.

Receptor Tyrosine Kinases in Osteosarcoma: 2019 Update

The primary conclusions of our 2014 contribution to this series were as follows: Multiple receptor tyrosine kinases (RTKs) likely contribute to aggressive phenotypes in osteosarcoma and, therefore, inhibition of multiple RTKs is likely necessary for successful clinical outcomes. Inhibition of multiple RTKs may also be useful to overcome resistance to inhibitors of individual RTKs as well as resistance to conventional chemotherapies. Different combinations of RTKs are likely important in individual patients. AXL, EPHB2, FGFR2, IGF1R, and RET were identified as promising therapeutic targets by our in vitro phosphoproteomic/siRNA screen of 42 RTKs in the highly metastatic LM7 and 143B human osteosarcoma cell lines. This chapter is intended to provide an update on these topics as well as the large number of osteosarcoma clinical studies of inhibitors of multiple tyrosine kinases (multi-TKIs) that were recently published.