Mineral Nanomedicine to Enhance the Efficacy of Adjuvant Radiotherapy for Treating Osteosarcoma

It is vital to remove residual tumor cells after resection to avoid the recurrence and metastasis of osteosarcoma. In this study, a mineral nanomedicine, europium-doped calcium fluoride (CaF₂:Eu) nanoparticles (NPs), is developed to enhance the efficacy of adjuvant radiotherapy (i.e., surgical resection followed by radiotherapy) for tumor cell growth and metastasis of osteosarcoma. In vitro studies show that CaF₂:Eu NPs (200 μg/mL) exert osteosarcoma cell (143B)-selective toxicity and migration-inhibiting effects at a Eu dopant amount of 2.95 atomic weight percentage. These effects are further enhanced under X-ray irradiation (6 MeV, 4 Gy). Furthermore, in vivo tests show that intraosseous injection of CaF₂:Eu NPs and X-ray irradiation have satisfactory therapeutic efficacy in controlling primary tumor size and inhibiting primary tumor metastasis. Overall, our results suggest that CaF₂:Eu NPs with their osteosarcoma cell (143B)-selective toxicity and migration-inhibiting effects combined with radiotherapy might be nanomedicines for treating osteosarcoma after tumor resection.

PI3K p110α Blockade Enhances Anti-Tumor Efficacy of Abemaciclib in Human Colorectal Cancer Cells

Simple Summary

Colorectal cancer (CRC) is the third most common cancer and the second highest cause of cancer related mortality worldwide. Especially, the survival of advanced CRC patients who were failed to achieve durable remission after the anti-angiogenic and anti-epithelial growth factor receptor agents are still poor. The aim of our study was to investigate the anti-tumor activity of the CDK4/6 inhibitor, abemaciclib, as a single agent and to identify an optimal combination agent with abemaciclib in CRC cell lines. We confirmed that abemaciclib monotherapy showed anti-tumor activity and combination therapy with abemaciclib and BYL719 demonstrated synergistic effects in CRC cell lines. Moreover, our study suggested that PIK3CA mutation could be a predictive marker for efficacy of abemaciclib and BYL719 combination therapy. These findings provide novel insight into a possible therapeutic strategy for patients with relapsed and refractory CRC.

Abstract

Targeting cell cycle regulation in colorectal cancer has not been fully evaluated. We investigated the efficacy of the CDK4/6 inhibitor, abemaciclib, and confirmed a synergistic interaction for PI3K p110α and CDK dual inhibition in colorectal cancer cell lines. Caco-2 and SNU-C4 cell lines were selected to explore the mechanism of action for and resistance to abemaciclib. In vitro and in vivo models were used to validate the anti-tumor activity of abemaciclib monotherapy and BYL719 combination therapy. Abemaciclib monotherapy inhibited cell cycle progression and proliferation in Caco-2 and SNU-C4 cells. CDK2-mediated Rb phosphorylation and AKT phosphorylation appeared to be potential resistance mechanisms to abemaciclib monotherapy. Abemaciclib/BYL719 combination therapy demonstrated synergistic effects regardless of PIK3CA mutation status but showed greater efficacy in the PIK3CA mutated SNU-C4 cell line. Growth inhibition, cell cycle arrest, and migration inhibition were confirmed as mechanisms of action for this combination. In an SNU-C4 mouse xenograft model, abemaciclib/BYL719 combination resulted in tumor growth inhibition and apoptosis with tolerable toxicity. Dual blockade of PI3K p110α and CDK4/6 showed synergistic anti-tumor effects in vivo and in vitro in human colorectal cancer cell lines. This combination could be a promising candidate for the treatment of patients with advanced colorectal cancer.

Peptide-enabled receptor-binding-quantum dots for enhanced detection and migration inhibition of cancer cells

We report the efforts to construct active targeting quantum dots using receptor-binding peptide for enhanced detection and migration inhibition of cancer cells. Peptide E5 has specific binding with chemokine receptor 4 (CXCR4), which is a transmembrane G-coupled receptor involved in the metastasis of various types of cancers. E5 was introduced to the surface of CdSe/ZnS quantum dots via biotin-streptavidin interactions. The constructed CXCR4-targeting quantum dots (E5@QDs) was observed to display improved detection sensitivity and significantly enhanced binding affinity for CXCR4 over-expressed cancer cells, and the ability to inhibit cancer cells migration induced by CXCL12.

Co-Delivery of Eugenol and Dacarbazine by Hyaluronic Acid-Coated Liposomes for Targeted Inhibition of Survivin in Treatment of Resistant Metastatic Melanoma

While melanoma remains a challenge for oncologists, possibilities are being continuously explored to fight resistant metastatic melanoma more effectively. Eugenol is reported to inhibit survivin protein in breast cancer cells. Survivin is also overexpressed by melanoma cells, and is known to impart resistance to them against chemotherapy-induced apoptosis. To be able to fight resistant melanoma, we formulated hyaluronic acid (HA)-coated liposomes loaded with an effective combination of anti-melanoma agents (Dacarbazine and Eugenol), using a solvent injection method. Quality-by-Design (QbD) was applied to optimize and obtain a final formulation with the desired quality attributes, and within an acceptable size range. The optimized formulation was then subjected to performance analysis in cell lines. Coated-Dacarbazine Eugenol Liposomes were found to possess 95.08% cytotoxicity at a dacarbazine concentration of 0.5 µg/mL, while Dacarbazine Solution showed only 10.20% cytotoxicity at the same concentration. The number of late apoptotic cells was also found to be much higher (45.16% vs. 8.43%). Furthermore, migration assay and proliferation study also revealed significantly higher inhibition of cell migration and proliferation by Coated-Dacarbazine Eugenol Liposomes, signifying its potential against metastasis. Thus, surface-functionalized dacarbazine- and eugenol-loaded liposomes hold great promise against resistant and aggressive metastatic melanoma, with much less unwanted cytotoxicity and reduced doses of the chemotherapeutic agent.

Discovery of [1,2,3]Triazolo[4,5-d]pyrimidine Derivatives as Novel LSD1 Inhibitors

Lysine specific demethylase 1 (LSD1) plays a pivotal role in regulating the lysine methylation. The aberrant overexpression of LSD1 has been reported to be involved in the progression of certain human malignant tumors. Abrogation of LSD1 with RNAi or small molecule inhibitors may lead to the inhibition of cancer proliferation and migration. Herein, a series of [1,2,3]triazolo[4,5-d]pyrimidine derivatives were synthesized and evaluated for their LSD1 inhibitory effects. The structure-activity relationship studies (SARs) were conducted by exploring three regions of this scaffold, leading to the discovery of compound 27 as potent LSD1 inhibitor (IC₅₀ = 0.564 μM). Compound 27 was identified as a reversible LSD1 inhibitor and showed certain selectivity to LSD1 over monoamine oxidase A/B (MAO-A/B). When MGC-803 cells were treated with compound 27, the activity of LSD1 can be significantly inhibited, and the cell migration ability was also suppressed. Docking studies indicated that the hydrogen interaction between the nitrogen atom in the pyridine ring and Met332 could be responsible for the improved activity of 2-thiopyridine series. The [1,2,3]triazolo[4,5-d]pyrimidine scaffold can be used as the template for designing new LSD1 inhibitors.