Self-Assembling Imageable Silk Hydrogels for the Focal Treatment of Osteosarcoma

Advances in Osteosarcoma

PURPOSE OF REVIEW

This article gives a brief overview of the most recent developments in osteosarcoma treatment, including targeting of signaling pathways, immune checkpoint inhibitors, drug delivery strategies as single or combined approaches, and the identification of new therapeutic targets to face this highly heterogeneous disease.

RECENT FINDINGS

Osteosarcoma is one of the most common primary malignant bone tumors in children and young adults, with a high risk of bone and lung metastases and a 5-year survival rate around 70% in the absence of metastases and 30% if metastases are detected at the time of diagnosis. Despite the novel advances in neoadjuvant chemotherapy, the effective treatment for osteosarcoma has not improved in the last 4 decades. The emergence of immunotherapy has transformed the paradigm of treatment, focusing therapeutic strategies on the potential of immune checkpoint inhibitors. However, the most recent clinical trials show a slight improvement over the conventional polychemotherapy scheme. The tumor microenvironment plays a crucial role in the pathogenesis of osteosarcoma by controlling the tumor growth, the metastatic process and the drug resistance and paved the way of new therapeutic options that must be validated by accurate pre-clinical studies and clinical trials.

Sericultural By-Products: The Potential for Alternative Therapy in Cancer Drug Design

Major progress has been made in cancer research; however, cancer remains one of the most important health-related burdens. Sericulture importance is no longer limited to the textile industry, but its by-products, such as silk fibroin or mulberry, exhibit great impact in the cancer research area. Fibroin, the pivotal compound that is found in silk, owns superior biocompatibility and biodegradability, representing one of the most important biomaterials. Numerous studies have reported its successful use as a drug delivery system, and it is currently used to develop three-dimensional tumor models that lead to a better understanding of cancer biology and play a great role in the development of novel antitumoral strategies. Moreover, sericin's cytotoxic effect on various tumoral cell lines has been reported, but also, it has been used as a nanocarrier for target therapeutic agents. On the other hand, mulberry compounds include various bioactive elements that are well known for their antitumoral activities, such as polyphenols or anthocyanins. In this review, the latest progress of using sericultural by-products in cancer therapy is discussed by highlighting their notable impact in developing novel effective drug strategies.

Recent advances in hydrogels-based osteosarcoma therapy

Osteosarcoma (OS), as a typical kind of bone tumors, has a high incidence among adolescents. Traditional tumor eradication avenues for OS such as chemotherapy, surgical therapy and radiation therapy usually have their own drawbacks including recurrence and metastasis. In addition, another serious issue in the treatment of OS is bone repair because the bone after tumor invasion usually has difficulty in repairing itself. Hydrogels, as a synthetic or natural platform with a porous three-dimensional structure, can be applied as desirable platforms for OS treatment. They can not only be used as carriers for tumor therapeutic drugs but mimic the extracellular matrix for the growth and differentiation of mesenchymal stem cells (MSCs), thus providing tumor treatment and enhancing bone regeneration at the same time. This review focuses the application of hydrogels in OS suppression and bone regeneration, and give some suggests on future development.

Fluoride Exposure Suppresses Proliferation and Enhances Endoplasmic Reticulum Stress and Apoptosis Pathways in Hepatocytes by Downregulating Sirtuin-1

Objective

To explore the function and mechanism of Sirt-1 in fluorine-induced liver injury.

Method

Fluorosis rats were first established. The fluorine content, pathological structure, collagen fibers, and fibrosis in liver tissues were tested through the fluoride ion selective electrode method, H&E, Masson, and Sirius red staining; alanine aminotransferase (ALT), aspartate aminotransferase (AST), interleukin 18 (IL-18), and tumor necrosis factor-α (TNF-α) levels in rat serum were also analyzed using ELISA kits. Then, the fluorosis cell model was built, which was also alleviated with NaF, Sirt-1 siRNAs, or endoplasmic reticulum stress (ERS) alleviator (4-PBA). CCK-8 also assessed cell proliferation; RT-qPCR or Western blots detect sirtuin-1 (Sirt-1), protein kinase R- (PKR-) like endoplasmic reticulum kinase (PERK), and endoplasmic reticulum stress (ERS) and apoptosis-related protein levels in liver tissue.

Results

Our results uncovered that fluorine exposure could aggravate the pathological damage and fibrosis of rat liver tissues and increase indicators related to liver injury. And fluoride exposure also could downregulate Sirt-1 and upregulate ERS-related proteins (PERK, 78-kD glucose-regulated protein (GRP-78), and activating transcription factor 6 (ATF6)) and apoptosis-related protein (caspase-3 and C/EBP-homologous protein (CHOP)) in rat liver tissues. Besides, we proved that fluoride exposure could suppress proliferation and enhances ERS and apoptotic pathways in AML12 cells by downregulating Sirt-1. Moreover, we revealed that ERS alleviator (4-PBA) could induce proliferation and prevent ERS and apoptosis in fluorine-exposed AML12 cells.

Conclusions

We suggested that fluorine exposure can induce hepatocyte ERS and apoptosis through downregulation of Sirt-1.