Low-dose eribulin reduces lung metastasis of osteosarcoma in vitro and in vivo

Eribulin inhibits growth of cutaneous squamous cell carcinoma cell lines and a novel patient-derived xenograft

Advanced cutaneous squamous cell carcinoma (cSCC) is treated with chemotherapy and/or radiotherapy, but these typically fail to achieve satisfactory clinical outcomes. There have been no preclinical studies to evaluate the effectiveness of eribulin against cSCC. Here, we examine the effects of eribulin using cSCC cell lines and a novel cSCC patient-derived xenograft (PDX) model. In the cSCC cell lines (A431 and DJM-1 cells), eribulin was found to inhibit tumor cell proliferation in vitro as assessed by cell ATP levels. DNA content analysis by fluorescence-activated cell sorting (FACS) showed that eribulin induced G2/M cell cycle arrest and apoptosis. In xenograft models of cSCC cell lines, the administration of eribulin suppressed tumor growth in vivo. We also developed a cSCC patient-derived xenograft (PDX) which reproduces the histological and genetic characteristics of a primary tumor. Pathogenic mutations in TP53 and ARID2 were detected in the patient's metastatic tumor and in the PDX tumor. The cSCC-PDX responded well to the administration of eribulin and cisplatin. In conclusion, the present study shows the promising antineoplastic effects of eribulin in cSCC. Also, we established a novel cSCC-PDX model that preserves the patient's tumor. This PDX could assist researchers who are exploring innovative therapies for cSCC.

The emerging role of microtubules in invasion plasticity

The ability of cells to switch between different invasive modes during metastasis, also known as invasion plasticity, is an important characteristic of tumor cells that makes them able to resist treatment targeted to a particular invasion mode. Due to the rapid changes in cell morphology during the transition between mesenchymal and amoeboid invasion, it is evident that this process requires remodeling of the cytoskeleton. Although the role of the actin cytoskeleton in cell invasion and plasticity is already quite well described, the contribution of microtubules is not yet fully clarified. It is not easy to infer whether destabilization of microtubules leads to higher invasiveness or the opposite since the complex microtubular network acts differently in diverse invasive modes. While mesenchymal migration typically requires microtubules at the leading edge of migrating cells to stabilize protrusions and form adhesive structures, amoeboid invasion is possible even in the absence of long, stable microtubules, albeit there are also cases of amoeboid cells where microtubules contribute to effective migration. Moreover, complex crosstalk of microtubules with other cytoskeletal networks participates in invasion regulation. Altogether, microtubules play an important role in tumor cell plasticity and can be therefore targeted to affect not only cell proliferation but also invasive properties of migrating cells.

Recent and Ongoing Research into Metastatic Osteosarcoma Treatments

The survival rate for metastatic osteosarcoma has not improved for several decades, since the introduction and refinement of chemotherapy as a treatment in addition to surgery. Over two thirds of metastatic osteosarcoma patients, many of whom are children or adolescents, fail to exhibit durable responses and succumb to their disease. Concerted efforts have been made to increase survival rates through identification of candidate therapies via animal studies and early phase trials of novel treatments, but unfortunately, this work has produced negligible improvements to the survival rate for metastatic osteosarcoma patients. This review summarizes data from clinical trials of metastatic osteosarcoma therapies as well as pre-clinical studies that report efficacy of novel drugs against metastatic osteosarcoma in vivo. Considerations regarding the design of animal studies and clinical trials to improve survival outcomes for metastatic osteosarcoma patients are also discussed.

Eribulin activity in soft tissue sarcoma monolayer and three-dimensional cell line models: could the combination with other drugs improve its antitumoral effect?

BACKGROUND

Eribulin has shown antitumour activity in some soft tissue sarcomas (STSs), but it has only been approved for advanced liposarcoma (LPS).

METHODS

In this study, we evaluated the effect of eribulin on proliferation, migration and invasion capabilities in LPS, leiomyosarcoma (LMS) and fibrosarcoma (FS) models, using both monolayer (2D) and three-dimensional (3D) spheroid cell cultures. Additionally, we explored combinations of eribulin with other drugs commonly used in the treatment of STS with the aim of increasing its antitumour activity.

RESULTS

Eribulin showed activity inhibiting proliferation, 2D and 3D migration and invasion in most of the cell line models. Furthermore, we provide data that suggest, for the first time, a synergistic effect with ifosfamide in all models, and with pazopanib in LMS as well as in myxoid and pleomorphic LPS.

CONCLUSIONS

Our results support the effect of eribulin on LPS, LMS and FS cell line models. The combination of eribulin with ifosfamide or pazopanib has shown in vitro synergy, which warrants further clinical research.

Charting a path for prioritization of novel agents for clinical trials in osteosarcoma: A report from the Children's Oncology Group New Agents for Osteosarcoma Task Force

Osteosarcoma is the most common bone tumor in children and young adults. Metastatic and relapsed disease confer poor prognosis, and there have been no improvements in outcomes for several decades. The disease's biological complexity, lack of drugs developed specifically for osteosarcoma, imperfect preclinical models, and limits of existing clinical trial designs have contributed to lack of progress. The Children's Oncology Group Bone Tumor Committee established the New Agents for Osteosarcoma Task Force to identify and prioritize agents for inclusion in clinical trials. The group identified multitargeted tyrosine kinase inhibitors, immunotherapies targeting B7-H3, CD47-SIRPα inhibitors, telaglenastat, and epigenetic modifiers as the top agents of interest. Only multitargeted tyrosine kinase inhibitors met all criteria for frontline evaluation and have already been incorporated into an upcoming phase III study concept. The task force will continue to reassess identified agents of interest as new data become available and evaluate novel agents using this method.

Identification of Kinesin Family Member 2A (KIF2A) as a Promising Therapeutic Target for Osteosarcoma

Background

Osteosarcoma is known as a type of common human bone malignancy, and more therapeutic targets are still required to combat this disease. In recent years, the involvement of KIF2A in cancer progression has been widely revealed; however, its potential effect on osteosarcoma development remains unknown. This study is to assess the KIF2A expression levels in human osteosarcoma tissues and explore its potential role in osteosarcoma development.

Methods

Immunohistochemical (IHC) assays were conducted to evaluate the expression levels of KIF2A in a total of 74 samples of osteosarcoma tissues and adjacent nontumor tissues. According to the staining intensity in tumor tissues, patients were divided into highly expressed and low expression KIF2A groups. The possible links between the KIF2A expression and the clinical pathological features were explored and analyzed, and the effects of KIF2A on osteosarcoma cell proliferation, migration, and invasion were detected through colony formation assay, MTT assay, wound closure assay, and transwell assay, respectively. The effects of KIF2A on tumor growth and metastasis were detected by the use of animal models.

Results

KIF2A was highly expressed in human osteosarcoma tissues. Meanwhile, KIF2A was obviously correlated to the tumor size (P = 0.001^∗) and clinical stage (P = 0.014^∗) of osteosarcoma patients. Our results also revealed that the ablation of KIF2A dramatically blocked the proliferation, migration, and invasion capacity of osteosarcoma cells in vitro and blocked tumor growth and metastasis in mice.

Conclusions

We investigated the involvement of KIF2A in the development and metastasis of osteosarcoma and therefore thought KIF2A as a promising therapeutic target for osteosarcoma treatment.

Molecular evidence of IGFBP-3 dependent and independent VD3 action and its nonlinear response on IGFBP-3 induction in prostate cancer cells

Background

Clinical trials have been conducted to clarify the beneficial effects of VD3 (1α,25-dihydroxy vitamin D3, also known as calcitriol) treatment in prostate cancer. However, the molecular mechanisms underlying these effects are not fully understood. Recent studies on IGFBP-3 have indicated its intracellular functions in cell growth and apoptosis. The aim of this study was to confirm the benefits of low-dose VD3 treatment and clarify the molecular mechanisms underlying these beneficial effects in prostate cancer cells.

Methods

The molecular effects of simultaneous treatment of LNCaP cells and their genetically modified cell lines with low concentration of docetaxel and VD3 were biologically and biochemically analyzed. To further determine the effects of VD3 treatment on IGFBP-3 induction system, cells were temporarily treated with VD3 in combination with a transcriptional inhibitor or protein synthesis inhibitor. Bcl-2 protein and its mRNA behavior were also observed in Igfbp-3 expression-modified LNCaP cells to determine the involvement of IGFBP-3 in the suppression of Bcl-2 by VD3 treatment.

Results

Changes in IGFBP-3 expression levels in LNCaP cells indicated that it mediated the inhibition of cell growth induced by VD3 treatment. IGFBP-3 was also found to be a mediator of the enhanced cytotoxicity of prostate cancer cells to VD3 in combination with the anti-cancer drug. We further identified the distinct property of the IGFBP-3 induction system, wherein temporal VD3 stimulation-induced prolonged IGFBP-3 expression and VD3 treatment-induced increase in IGFBP-3 expression were optimized based on the protein concentration rather than the mRNA concentration. Meanwhile, Bcl-2 expression was down-regulated by VD3 treatment in an IGFBP-3-independent manner.

Conclusion

These findings indicate the molecular mechanisms of IGFBP-3 induction stimulated by VD3 and IGFBP-3 independent Bcl-2 suppression by VD3 treatment in prostate cancer cells. The results could prompt a re-evaluation of VD3 usage in therapy for patients with prostate cancer.