Glycol chitosan incorporated retinoic acid chlorochalcone (RACC) nanoparticles in the treatment of Osteosarcoma

Modification and Functionalization of Polymers for Targeting to Bone Cancer and Bone Regeneration

Bone is one of the most complex, inaccessible body structures, responsible for calcium storage and haematopoiesis. The second highest cause of death across the world is cancer. Amongst all the types of cancers, bone cancer treatment modalities are limited due to the structural complexity and inaccessibility of bones. The worldwide incidence of bone diseases and bone defects due to cancer, infection, trauma, age-related bone degeneration is increasing. Currently different conventional therapies are available for bone cancer such as chemotherapy, surgery and radiotherapy, but they have several disadvantages associated with them. Nanomedicine is being extensively researched as viable therapeutics to mitigate drug resistance in cancer therapy and promote bone regeneration. Several natural polymers such as chitosan, dextran, alginate, hyaluronic acid, and synthetic polymers like polyglycolic acid, poly(lactic-co-glycolic acid), polycaprolactone are investigated for their application in nanomedicine for bone cancer treatment and bone regeneration. Nanocarriers have shown promising results in preclinical experimental studies. However, they still face a major drawback of inadequate targetability. The paper summarizes the status of research and the progress made so far in modifications and functionalization of natural polymers for improving their site specificity and targeting for effective treatment of bone cancer and enhancing bone regeneration.

Advances of smart nano-drug delivery systems in osteosarcoma treatment

Nanotechnology has recently become popular due to its potential for biomedical applications, especially for cancer treatment. Nanotechnology, featuring responsiveness to stimuli and stable drug release, has been widely used for the delivery of chemotherapeutic drugs, which are commonly used in the treatment of osteosarcoma. Smart stimuli-responsive nanotechnology is expected to improve the treatment of osteosarcoma. Herein, we focus on the latest research on nanomaterials in treating osteosarcoma that respond to internal and external stimuli. We also discuss nanocarriers with targeting ligands and the use of smart nanotechnology to partially reverse the multidrug resistance of osteosarcoma.

Chitosan applications in studying and managing osteosarcoma

Osteosarcoma has a high prevalence among children and adolescents. Common treatments of this disease are not promising enough. Molecular processes involved in the pathogenesis of osteosarcoma are not fully understood. Besides, the remnants of tumor cells after surgery can cause bone destruction and recurrence of the disease. Thus, there is a need to develop novel drugs or enhancing the currently-used drugs as well as identifying bone-repairing methods. Chitosan is a natural compound produced by the deacetylation of chitin. Research has shown that chitosan can be used in various fields due to its beneficial effects, such as biodegradability and biocompatibility. Regarding cancer, chitosan exerts several anti-tumor activities. Moreover, it can be used in diagnostic techniques, drug delivery systems, and cell culture methods. Herein, we aim to discuss the potential roles of chitosan in studying and treating osteosarcoma. We review the literature on chitosan's applications as a drug delivery system and how it can be combined with other substances to improve its ability of local drug delivery. We take a look into the studies concerning the possible benefits of chitosan in the field of bone tissue engineering and 3D culturing. Furthermore, anti-cancer activities of different compounds of chitosan are reviewed.

Retraction Note: Glycol chitosan incorporated retinoic acid chlorochalcone (RACC) nanoparticles in the treatment of Osteosarcoma

This article has been retracted. Please see the Retraction Notice for more detail: https://doi.org/10.1186/s12944-020-01416-2.

Effects of chitosan and oligochitosans on the phosphatidylinositol 3-kinase-AKT pathway in cancer therapy

Phosphatidylinositol 3-kinase (PI3K)-AKT pathway is one of the most important kinase signaling networks in the context of cancer development and treatment. Aberrant activation of AKT, the central mediator of this pathway, has been implicated in numerous malignancies including endometrial, hepatocellular, breast, colorectal, prostate, and, cervical cancer. Thus regulation and blockage of this kinase and its key target nodes is an attractive approach in cancer therapy and diverse efforts have been done to achieve this aim. Chitosan is a carbohydrate with multiple interesting applications in cancer diagnosis and treatment strategies. This bioactive polymer and its derivative oligomers commonly used in drug/DNA delivery methods due to their functional properties which improve efficiency of delivery systems. Further, these compounds exert anti-tumor roles through the stimulation of apoptosis, immune enhancing potency, anti-oxidative features and anti-angiogenic roles. Due to the importance of PI3K-AKT signaling in cancer targeting and treatment resistance, this review discusses the involvement of chitosan, oligochitosaccharides and carriers based on these chemicals in the regulation of this pathway in different tumors.

Anticancer Effects of Zinc Oxide Nanoparticles Through Altering the Methylation Status of Histone on Bladder Cancer Cells

Purpose

Zinc oxide nanoparticles (nZnO) have been widely used in the medicine field. Numerous mechanistic studies for nZnO’s anticancer effects are merely performed under high concentration exposure. However, possible anticancer mechanisms of epigenetic dysregulation induced by low doses of nZnO are unclear.

Methods

nZnO were characterized and bladder cancer T24 cells were treated with nZnO for 48 hrs at different exposure concentrations. Cell cycle, apoptosis, cell migration and invasion were determined. We performed qRT-PCR, Western blot and chromatin immunoprecipitation to detect the mRNA and protein levels of signaling pathway cascades for histone modification.

Results

In this study, we investigated the potential anticancer effects and mechanisms of nZnO on histone modifications in bladder cancer T24 cells upon low-dose exposure. Our findings showed that low concentrations of nZnO resulted in cell cycle arrest at S phase, facilitated cellular late apoptosis, repressed cell invasion and migration after 48 hrs exposure. These anticancer effects could be attributed to increased RUNX3 levels resulting from reduced H3K27me³ occupancy on the RUNX3 promoter, as well as decreased contents of histone methyltransferase EZH2 and the trimethylation of histone H3K27. Our findings reveal that nZnO are able to enter into the cytoplasm and nucleus of T24 cells. Additionally, both particles and ions from nZnO may jointly contribute to the alteration of histone methylation. Moreover, sublethal nZnO-conducted anticancer effects and epigenetic mechanisms were not associated with oxidative stress or DNA damage.

Conclusion

We reveal a novel epigenetic mechanism for anticancer effects of nZnO in bladder cancer cells under low-dose exposure. This study will provide experimental basis for the toxicology and cancer therapy of nanomaterials.