Discovery and Validation of a Compound to Target Ewing's Sarcoma

Participation of the TBP-associated factors (TAFs) in cell differentiation

The understanding of the mechanisms that regulate gene expression to establish differentiation programs and determine cell lineages, is one of the major challenges in Developmental Biology. Besides the participation of tissue-specific transcription factors and epigenetic processes, the role of general transcription factors has been ignored. Only in recent years, there have been scarce studies that address this issue. Here, we review the studies on the biological activity of some TATA-box binding protein (TBP)-associated factors (TAFs) during the proliferation of stem/progenitor cells and their involvement in cell differentiation. Particularly, the accumulated evidence suggests that TAF4, TAF4b, TAF7L, TAF8, TAF9, and TAF10, among others, participate in nervous system development, adipogenesis, myogenesis, and epidermal differentiation; while TAF1, TAF7, TAF15 may be involved in the regulation of stem cell proliferative abilities and cell cycle progression. On the other hand, evidence suggests that TBP variants such as TBPL1 and TBPL2 might be regulating some developmental processes such as germ cell maturation and differentiation, myogenesis, or ventral specification during development. Our analysis shows that it is necessary to study in greater depth the biological function of these factors and its participation in the assembly of specific transcription complexes that contribute to the differential gene expression that gives rise to the great diversity of cell types existing in an organism. The understanding of TAFs' regulation might lead to the development of new therapies for patients which suffer from mutations, alterations, and dysregulation of these essential elements of the transcriptional machinery.

Novel Nanoparticle-Based Treatment and Imaging Modalities

Over the last twenty years, nanomaterials have been widely used in cancer research [...].

Ewing Sarcoma Meets Epigenetics, Immunology and Nanomedicine: Moving Forward into Novel Therapeutic Strategies

Ewing Sarcoma (EWS) is an aggressive bone and soft tissue tumor that mainly affects children, adolescents, and young adults. The standard therapy, including chemotherapy, surgery, and radiotherapy, has substantially improved the survival of EWS patients with localized disease. Unfortunately, this multimodal treatment remains elusive in clinics for those patients with recurrent or metastatic disease who have an unfavorable prognosis. Consistently, there is an urgent need to find new strategies for patients that fail to respond to standard therapies. In this regard, in the last decade, treatments targeting epigenetic dependencies in tumor cells and the immune system have emerged into the clinical scenario. Additionally, recent advances in nanomedicine provide novel delivery drug systems, which may address challenges such as side effects and toxicity. Therefore, therapeutic strategies stemming from epigenetics, immunology, and nanomedicine yield promising alternatives for treating these patients. In this review, we highlight the most relevant EWS preclinical and clinical studies in epigenetics, immunotherapy, and nanotherapy conducted in the last five years.

Targeted Nanoparticles with High Heating Efficiency for the Treatment of Endometriosis with Systemically Delivered Magnetic Hyperthermia

Endometriosis is a devastating disease in which endometrial-like tissue forms lesions outside the uterus. It causes infertility and severe pelvic pain in ≈176 million women worldwide, and there is currently no cure for this disease. Magnetic hyperthermia could potentially eliminate widespread endometriotic lesions but has not previously been considered for treatment because conventional magnetic nanoparticles have relatively low heating efficiency and can only provide ablation temperatures (>46 °C) following direct intralesional injection. This study is the first to describe nanoparticles that enable systemically delivered magnetic hyperthermia for endometriosis treatment. When subjected to an alternating magnetic field (AMF), these hexagonal iron-oxide nanoparticles exhibit extraordinary heating efficiency that is 6.4× greater than their spherical counterparts. Modifying nanoparticles with a peptide targeted to vascular endothelial growth factor receptor 2 (VEGFR-2) enhances their endometriosis specificity. Studies in mice bearing transplants of macaque endometriotic tissue reveal that, following intravenous injection at a low dose (3 mg per kg), these nanoparticles efficiently accumulate in endometriotic lesions, selectively elevate intralesional temperature above 50 °C upon exposure to external AMF, and completely eradicate them with a single treatment. These nanoparticles also demonstrate promising potential as magnetic resonance imaging (MRI) contrast agents for precise detection of endometriotic tissue before AMF application.

Enhanced tumor accumulation and therapeutic efficacy of liposomal drugs through over-threshold dosing

Background

Most intravenously administered drug-loaded nanoparticles are taken up by liver Kupffer cells, and only a small portion can accumulate at the tumor, resulting in an unsatisfactory therapeutic efficacy and side effects for chemotherapeutic agents. Tumor-targeted drug delivery proves to be the best way to solve this problem; however, the complex synthesis, or surface modification process, together with the astonishing high cost make its clinical translation nearly impossible.

Methods

Referring to Ouyang’s work and over-threshold dosing theory in general, blank PEGylated liposomes (PEG-Lipo) were prepared and used as tumor delivery enhancers to determine whether they could significantly enhance the tumor accumulation and in vivo antitumor efficacy of co-injected liposomal ACGs (PEG-ACGs-Lipo), a naturally resourced chemotherapeutic. Here, the phospholipid dose was used as an indicator of the number of liposomes particles with similar particle sizes, and the liposomes was labelled with DiR, a near-red fluorescent probe, to trace their in vivo biodistribution. Two mouse models, 4T1-bearing and U87-bearing, were employed for in vivo examination.

Results

PEG-Lipo and PEG-ACGs-Lipo had similar diameters. At a low-threshold dose (12 mg/kg equivalent phospholipids), PEG-Lipo was mainly distributed in the liver rather than in the tumor, with the relative tumor targeting index (RTTI) being ~ 0.38 at 72 h after administration. When over-threshold was administered (50 mg/kg or 80 mg/kg of equivalent phospholipids), a much higher and quicker drug accumulation in tumors and a much lower drug accumulation in the liver were observed, with the RTTI increasing to ~ 0.9. The in vivo antitumor study in 4T1 tumor-bearing mice showed that, compared to PEG-ACGs-Lipo alone (2.25 mg/kg phospholipids), the co-injection of a large dose of blank PEG-Lipo (50 mg/kg of phospholipids) significantly reduced the tumor volume of the mice by 22.6% (P < 0.05) and enhanced the RTTI from 0.41 to 1.34. The intravenous injection of a low drug loading content (LDLC) of liposomal ACGs (the same dose of ACGs at 50 mg/kg of equivalent phospholipids) achieved a similar tumor inhibition rate (TIR) to that of co-injection. In the U87 MG tumor-bearing mouse model, co-injection of the enhancer also significantly promoted the TIR (83.32% vs. 66.80%, P < 0.05) and survival time of PEG-ACGs-Lipo.

Conclusion

An over-threshold dosing strategy proved to be a simple and feasible way to enhance the tumor delivery and antitumor efficacy of nanomedicines and was benefited to benefit their clinical result, especially for liposomal drugs.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01349-1.