HDL nanoparticles targeting sonic hedgehog subtype medulloblastoma

State of the art in pediatric nanomedicines

In recent years, the continuous development of innovative nanopharmaceuticals is expanding their biomedical and clinical applications. Nanomedicines are being revolutionized to circumvent the limitations of unbound therapeutic agents as well as overcome barriers posed by biological interfaces at the cellular, organ, system, and microenvironment levels. In many ways, the use of nanoconfigured delivery systems has eased challenges associated with patient differences, and in our opinion, this forms the foundation for their potential usefulness in developing innovative medicines and diagnostics for special patient populations. Here, we present a comprehensive review of nanomedicines specifically designed and evaluated for disease management in the pediatric population. Typically, the pediatric population has distinguishing needs relative to those of adults majorly because of their constantly growing bodies and age-related physiological changes, which often need specialized drug formulation interventions to provide desirable therapeutic effects and outcomes. Besides, child-centric drug carriers have unique delivery routes, dosing flexibility, organoleptic properties (e.g., taste, flavor), and caregiver requirements that are often not met by traditional formulations and can impact adherence to therapy. Engineering pediatric medicines as nanoconfigured structures can potentially resolve these limitations stemming from traditional drug carriers because of their unique capabilities. Consequently, researchers from different specialties relentlessly and creatively investigate the usefulness of nanomedicines for pediatric disease management as extensively captured in this compilation. Some examples of nanomedicines covered include nanoparticles, liposomes, and nanomicelles for cancer; solid lipid and lipid-based nanostructured carriers for hypertension; self-nanoemulsifying lipid-based systems and niosomes for infections; and nanocapsules for asthma pharmacotherapy.

Medulloblastoma targeted therapy: From signaling pathways heterogeneity and current treatment dilemma to the recent advances in development of therapeutic strategies

Medulloblastoma (MB) is a major pediatric malignant brain tumor that arises in the cerebellum. MB tumors exhibit highly heterogeneous driven by diverse genetic alterations and could be divided into four major subgroups based on their different biological drivers and molecular features (Wnt, Sonic hedgehog (Shh), group 3, and group 4 MB). Even though the therapeutic strategies for each MB subtype integrate their pathogenesis and were developed to focus on their specific target sites, the unexpected drug non-selective cytotoxicity, low drug accumulation in the brain, and complexed MB tumor microenvironment still be huge obstacles to achieving satisfied MB therapeutic efficiency. This review discussed the current advances in modern MB therapeutic strategy development. Through the recent advances in knowledge of the origin, molecular pathogenesis of MB subtypes and their current therapeutic barriers, we particularly reviewed the current development in advanced MB therapeutic strategy committed to overcome MB treatment obstacles, focusing on novel signaling pathway targeted therapeutic agents and their combination discovery, advanced drug delivery systems design, and MB immunotherapy strategy development.

Peptide-Functionalized and Drug-Loaded Tomato Bushy Stunt Virus Nanoparticles Counteract Tumor Growth in a Mouse Model of Shh-Dependent Medulloblastoma

Sonic hedgehog medulloblastoma (SHH-MB) accounts for 25-30% of all MBs, and conventional therapy results in severe long-term side effects. New targeted therapeutic approaches are urgently needed, drawing also on the fields of nanoparticles (NPs). Among these, plant viruses are very promising, and we previously demonstrated that tomato bushy stunt virus (TBSV), functionalized on the surface with CooP peptide, specifically targets MB cells. Here, we tested the hypothesis that TBSV-CooP can specifically deliver a conventional chemotherapeutic drug (i.e., doxorubicin, DOX) to MB in vivo. To this aim, a preclinical study was designed to verify, by histological and molecular methods, if multiple doses of DOX-TBSV-CooP were able to inhibit tumor progression of MB pre-neoplastic lesions, and if a single dose was able to modulate pro-apoptotic/anti-proliferative molecular signaling in full-blown MBs. Our results demonstrate that when DOX is encapsulated in TBSV-CooP, its effects on cell proliferation and cell death are similar to those obtained with a five-fold higher dose of non-encapsulated DOX, both in early and late MB stages. In conclusion, these results confirm that CooP-functionalized TBSV NPs are efficient carriers for the targeted delivery of therapeutics to brain tumors.

Ligand Installation to Polymeric Micelles for Pediatric Brain Tumor Targeting

Medulloblastoma is a life-threatening disease with poor therapeutic outcomes. In chemotherapy, low drug accumulation has been a cause of these outcomes. Such inadequate response to treatments has been associated with low drug accumulation, particularly with a limited cellular uptake of drugs. Recently, the conjugation of drugs to ligand molecules with high affinity to tumor cells has attracted much attention for enhancing drug internalization into target cells. Moreover, combining tumor-targeting ligands with nano-scaled drug carriers can potentially improve drug loading capacity and the versatility of the delivery. Herein, we focused on the possibility of targeting CD276/B7-H3, which is highly expressed on the medulloblastoma cell membrane, as a strategy for enhancing the cellular uptake of ligand-installed nanocarriers. Thus, anti-CD276 antibodies were conjugated on the surface of model nanocarriers based on polyion complex micelles (PIC/m) via click chemistry. The results showed that the anti-CD276 antibody-installed PIC/m improved intracellular delivery into CD276-expressing medulloblastoma cells in a CD276-dependent manner. Moreover, increasing the number of antibodies on the surface of micelles improved the cellular uptake efficiency. These observations indicate the potential of anti-CD276 antibody-installed nanocarriers for promoting drug delivery in medulloblastoma.

Nanoparticles for Drug and Gene Delivery in Pediatric Brain Tumors' Cancer Stem Cells: Current Knowledge and Future Perspectives

Primary malignant brain tumors are the most common solid neoplasm in childhood. Despite recent advances, many children affected by aggressive or metastatic brain tumors still present poor prognosis, therefore the development of more effective therapies is urgent. Cancer stem cells (CSCs) have been discovered and isolated in both pediatric and adult patients with brain tumors (e.g., medulloblastoma, gliomas and ependymoma). CSCs are a small clonal population of cancer cells responsible for brain tumor initiation, maintenance and progression, displaying resistance to conventional anticancer therapies. CSCs are characterized by a specific repertoire of surface markers and intracellular specific pathways. These unique features of CSCs biology offer the opportunity to build therapeutic approaches to specifically target these cells in the complex tumor bulk. Treatment of pediatric brain tumors with classical chemotherapeutic regimen poses challenges both for tumor location and for the presence of the blood-brain barrier (BBB). Lastly, the application of chemotherapy to a developing brain is followed by long-term sequelae, especially on cognitive abilities. Novel avenues are emerging in the therapeutic panorama taking advantage of nanomedicine. In this review we will summarize nanoparticle-based approaches and the efficacy that NPs have intrinsically demonstrated and how they are also decorated by biomolecules. Furthermore, we propose novel cargoes together with recent advances in nanoparticle design/synthesis with the final aim to specifically target the insidious CSCs population in the tumor bulk.

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

Simple Summary

Ewing Sarcoma treatment is traditionally based on chemotherapy, surgery, and radiotherapy. Although these standard of care regimens are efficient at early disease stages, many patients fail to respond appropriately, which has prompted the search for more efficacious and specific treatments. A deeper understanding of the basic molecular mechanisms underlying the biology of both tumor cells and the tumor microenvironment, as well as advances in drug delivery, has led to the development of different approaches to improve the treatment in Ewing Sarcoma patients. Thus, epigenetic, and immunotherapy-based drugs, along with nanotechnology delivery strategies, represent novel preclinical and clinical studies in the treatment of Ewing Sarcoma. In this review, we provide a comprehensive overview of these emerging therapeutic strategies and summarize the potential of the latest preclinical and clinical trials in Ewing Sarcoma research. Finally, we underline the value and future directions of these new treatments.

Abstract

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.

High density lipoprotein nanoparticle as delivery system for radio-sensitising miRNA: An investigation in 2D/3D head and neck cancer models

Radiotherapy is one of the main treatment options for head and neck cancer patients. However, its clinical efficacy is hindered by both radiation induced side effects and radio-resistance. Radio-sensitising approaches with acceptable toxicity are being actively investigated. Among these, RNA therapeutics have great potentials as radio-sensitisers owing to their ability to target pathways specific to radio-resistance. However, their clinical translation is challenging due to delivery issues. Herein, we report the application of high-density lipoprotein nanoparticle (HDL NPs) as a biocompatible delivery system for a well-established radio-sensitising RNA, miR-34a. A simple/fast microfluidic based technique was used to prepare miR-34a-HDL NPs. Profiling of the radiation response in the UM-SCC-1 head and neck cancer cell line confirmed reduced metabolic activity and increased radiation induced apoptosis upon treatment with miR-34a-HDL NPs. The radio-sensitising properties of miR-34a-HDL NPs were further confirmed in a more biologically relevant co-culture spheroid model of head and neck cancer. Increased apoptotic activity and disrupted cell cycle were induced by miR-34a delivered by HDL NPs. The enhanced radio-biologic effects observed in both 2D and 3D models confirmed the utility of HDL NPs as an efficient delivery system for radio-sensitising RNA.

Nanoparticles for Diagnosis and Target Therapy in Pediatric Brain Cancers

Pediatric brain tumors represent the most common types of childhood cancer and novel diagnostic and therapeutic solutions are urgently needed. The gold standard treatment option for brain cancers in children, as in adults, is tumor resection followed by radio- and chemotherapy, but with discouraging therapeutic results. In particular, the last two treatments are often associated to significant neurotoxicity in the developing brain of a child, with resulting disabilities such as cognitive problems, neuroendocrine, and neurosensory dysfunctions/deficits. Nanoparticles have been increasingly and thoroughly investigated as they show great promises as diagnostic tools and vectors for gene/drug therapy for pediatric brain cancer due to their ability to cross the blood–brain barrier. In this review we will discuss the developments of nanoparticle-based strategies as novel precision nanomedicine tools for diagnosis and therapy in pediatric brain cancers, with a particular focus on targeting strategies to overcome the main physiological obstacles that are represented by blood–brain barrier.

Biological protein mediated ferroptotic tumor nanotherapeutics

Ferroptosis, a cell death pathway involving iron-related generation of lipid hydroperoxides for achieving incredible tumor suppression, has reignited the hope of chemotherapy in tumor treatment in the past decade. With extensive research studies, various bioactive proteins and cellular pathways have been demonstrated to regulate the occurrence and development of ferroptosis. The gradually established ferroptotic regulatory network is conducive to find effective proteins from a holistic perspective and guides better designs for future ferroptotic tumor therapies. The first section of this review summarizes the recent advances in ferroptotic regulatory mechanisms of proteins and attempts to clarify their latent function in the ferroptotic regulatory network. Second, the existing protein-mediated ferroptotic tumor nanotherapeutic strategies were reviewed, including the protein-mediated iron supplement, cell membrane transporter inhibition, glutathione peroxidase 4 interference, glutathione depletion, bioenzyme-mediated reactive oxygen species generation, heat shock protein inhibition, and tumor-overexpressed protein-triggered drug release for ferroptotic therapy. Finally, the future expectations and challenges of ferroptotic tumor nanotherapeutics for clinical cancer therapy are highlighted.

Tomato Bushy Stunt Virus Nanoparticles as a Platform for Drug Delivery to Shh-Dependent Medulloblastoma

Medulloblastoma (MB) is a primary central nervous system tumor affecting mainly young children. New strategies of drug delivery are urgent to treat MB and, in particular, the SHH-dependent subtype-the most common in infants-in whom radiotherapy is precluded due to the severe neurological side effects. Plant virus nanoparticles (NPs) represent an innovative solution for this challenge. Tomato bushy stunt virus (TBSV) was functionally characterized as a carrier for drug targeted delivery to a murine model of Shh-MB. The TBSV NPs surface was genetically engineered with peptides for brain cancer cell targeting, and the modified particles were produced on a large scale using Nicotiana benthamiana plants. Tests on primary cultures of Shh-MB cells allowed us to define the most efficient peptides able to induce specific uptake of TBSV. Immunofluorescence and molecular dynamics simulations supported the hypothesis that the specific targeting of the NPs was mediated by the interaction of the peptides with their natural partners and reinforced by the presentation in association with the virus. In vitro experiments demonstrated that the delivery of Doxorubicin through the chimeric TBSV allowed reducing the dose of the chemotherapeutic agent necessary to induce a significant decrease in tumor cells viability. Moreover, the systemic administration of TBSV NPs in MB symptomatic mice, independently of sex, confirmed the ability of the virus to reach the tumor in a specific manner. A significant advantage in the recognition of the target appeared when TBSV NPs were functionalized with the CooP peptide. Overall, these results open new perspectives for the use of TBSV as a vehicle for the targeted delivery of chemotherapeutics to MB in order to reduce early and late toxicity.

Nanotherapeutic approach to tackle chemotherapeutic resistance of cancer stem cells

Estimates indicate that cancer will become the leading cause of mortality worldwide in the future. Tumorigenesis is a complex process that involves self-sufficiency in signs of growth, insensitivity to anti-growth signals, prevention of apoptosis, unlimited replication, sustained angiogenesis, tissue invasion, and metastasis. Cancer stem cells (CSCs) have an important role in tumor development and resistance. Here we will approach phenotypic plasticity capacity, highly efficient DNA repair systems, anti-apoptotic machinery, sustained stemness features, interaction with the tumor microenvironment, and Notch, Wnt, and Hedgehog signaling pathways. The researches about CSCs as a target in cancer treatment has been growing. Many different options have pointed beneficial results, such as pathways and CSC-surface markers targeting. Besides its limitations, nanotherapeutics have emerged as a potential strategy in this context since they aim to improve pharmacokinetics, biodistribution, and reduce the side effects observed in traditional treatments. Nanoparticles have been studied in this field, mostly for drug delivery and a multitherapy approach. Another widely researched approaches in this area are related to heat therapy, such as photothermal therapy, photodynamic therapy and magnetic hyperthermia, besides molecular targeting. This review will contemplate the most relevant studies that have shown the effects of nanotherapeutics. In conclusion, although the studies analyzed are mostly preclinical, we believe that there is strong evidence that nanoparticles can increase the chances of a better prognosis to cancer in the future. It is also essential to transpose these findings to the clinic to confirm and better understand the role of nanotherapeutics in this context.

Drug Delivery Systems for Hedgehog Inhibitors in the Treatment of SHH-Medulloblastoma

Medulloblastoma (MB) is a highly aggressive pediatric tumor of the cerebellum. Hyperactivation of the Hedgehog (HH) pathway is observed in about 30% of all MB diagnoses, thereby bringing out its pharmacological blockade as a promising therapeutic strategy for the clinical management of this malignancy. Two main classes of HH inhibitors have been developed: upstream antagonists of Smoothened (SMO) receptor and downstream inhibitors of GLI transcription factors. Unfortunately, the poor pharmacological properties of many of these molecules have limited their investigation in clinical trials for MB. In this minireview, we focus on the drug delivery systems engineered for SMO and GLI inhibitors as a valuable approach to improve their bioavailability and efficiency to cross the blood-brain barrier (BBB), one of the main challenges in the treatment of MB.

Recent Developments in Nanomedicine for Pediatric Cancer

Cancer is the second biggest cause of death in children in the US. With the development of chemotherapy, there has been a substantial increase in the overall survival rate in the last 30 years. However, the overall mortality rate in children with cancer remains 25%, and many survivors experience a decline in overall quality of life and long-term adverse effects caused by treatments. Although cancer cells share common characteristics, pediatric cancers are different from adult cancers in their prevalence, mutation load, and drug response. Therefore, there is an urgent unmet need to develop therapeutic approaches specifically designed for children with cancer. Nanotechnology can potentially overcome the deficiencies of conventional methods of administering chemotherapy and ultimately improve clinical outcomes. The nanoparticle-based drug delivery systems can decrease the toxicity of therapy, provide a sustained or controlled drug release, improve the pharmacokinetic properties of loading contents, and achieve a targeted drug delivery with achievable modifications. Furthermore, therapeutic approaches based on combining nanoformulated drugs with novel immunotherapeutic agents are emerging. In this review, we discussed the recently developed nanotechnology-based strategies for treating blood and solid pediatric cancers.

Targeted reduction of cholesterol uptake in cholesterol-addicted lymphoma cells blocks turnover of oxidized lipids to cause ferroptosis

Normal human cells can either synthesize cholesterol or take it up from lipoproteins to meet their metabolic requirements. In some malignant cells, de novo cholesterol synthesis genes are transcriptionally silent or mutated, meaning that cholesterol uptake from lipoproteins is required for survival. Recent data suggest that lymphoma cells dependent upon lipoprotein-mediated cholesterol uptake are also subject to ferroptosis, an oxygen- and iron-dependent cell death mechanism triggered by accumulation of oxidized lipids in cell membranes unless the lipid hydroperoxidase, glutathione peroxidase 4 (GPX4), reduces these toxic lipid species. To study mechanisms linking cholesterol uptake with ferroptosis and determine the potential role of the high-density lipoprotein (HDL) receptor as a target for cholesterol depleting therapy, we treated lymphoma cell lines known to be sensitive to the reduction of cholesterol uptake with HDL-like nanoparticles (HDL NPs). HDL NPs are a cholesterol-poor ligand that binds to the receptor for cholesterol-rich HDLs, scavenger receptor type B1 (SCARB1). Our data reveal that HDL NP treatment activates a compensatory metabolic response in treated cells toward increased de novo cholesterol synthesis, which is accompanied by nearly complete reduction in expression of GPX4. As a result, oxidized membrane lipids accumulate, leading to cell death through a mechanism consistent with ferroptosis. We obtained similar results in vivo after systemic administration of HDL NPs in mouse lymphoma xenografts and in primary samples obtained from patients with lymphoma. In summary, targeting SCARB1 with HDL NPs in cholesterol uptake-addicted lymphoma cells abolishes GPX4, resulting in cancer cell death by a mechanism consistent with ferroptosis.

Drug repurposing towards targeting cancer stem cells in pediatric brain tumors

In the pediatric population, brain tumors represent the most commonly diagnosed solid neoplasms and the leading cause of cancer-related deaths globally. They include low-grade gliomas (LGGs), medulloblastomas (MBs), and other embryonal, ependymal, and neuroectodermal tumors. The mainstay of treatment for most brain tumors includes surgical intervention, radiation therapy, and chemotherapy. However, resistance to conventional therapy is widespread, which contributes to the high mortality rates reported and lack of improvement in patient survival despite advancement in therapeutic research. This has been attributed to the presence of a subpopulation of cells, known as cancer stem cells (CSCs), which reside within the tumor bulk and maintain self-renewal and recurrence potential of the tumor. An emerging promising approach that enables identifying novel therapeutic strategies to target CSCs and overcome therapy resistance is drug repurposing or repositioning. This is based on using previously approved drugs with known pharmacokinetic and pharmacodynamic characteristics for indications other than their traditional ones, like cancer. In this review, we provide a synopsis of the drug repurposing methodologies that have been used in pediatric brain tumors, and we argue how this selective compilation of approaches, with a focus on CSC targeting, could elevate drug repurposing to the next level.

HDL and cancer - causality still needs to be confirmed? Update 2020

An inverse correlation between high-density lipoprotein cholesterol (HDL-C) and cancer risk has been shown by several epidemiological studies. Some studies have even suggested that HDL-C can be used as a prognostic marker in patients with certain types of cancer. However, whether reduced HDL-C level is a consequential or causal factor in the development and progression of cancer remains a controversial issue. In this review, we update and summarize recent advances that highlight the role of HDL and some of its components in prognosis, diagnosis and treatment of cancer.

Engineered biomimetic nanoparticle for dual targeting of the cancer stem-like cell population in sonic hedgehog medulloblastoma

The sonic hedgehog subtype of medulloblastoma (SHH MB) is associated with treatment failure and poor outcome. Current strategies utilizing whole brain radiation therapy result in deleterious off-target effects on the normal developing childhood brain. Most conventional chemotherapies remain limited by ineffective blood-brain barrier (BBB) penetrance. These challenges signify an unmet need for drug carriers that can cross the BBB and deliver drugs to targeted sites with high drug-loading efficiency and long-term stability. We herein leverage the enhanced stability and targeting ability of engineered high-density lipoprotein-mimetic nanoparticles (eHNPs) to cross the BBB and deliver a SHH inhibitor effectively to the cancer stem-like cell population in SHH MB. Our microfluidic technology enabled highly reproducible production of multicomponent eHNPs incorporated with apolipoprotein A1, anti-CD15, and a SHH inhibitor (LDE225). We demonstrate the dual-targeted delivery and enhanced therapeutic effect of eHNP-A1-CD15-LDE225 via scavenger receptor class B type 1 (SR-B1) and CD15 on brain SHH MB cells in vitro, ex vivo, and in vivo. Moreover, we show that eHNP-A1 not only serves as a stable drug carrier, but also has a therapeutic effect itself through SR-B1-mediated intracellular cholesterol depletion in SHH MB cells. Through the facilitated and targeted cellular uptake of drugs and direct therapeutic role of this engineered biomimetic nanocarrier in SHH MB, our multifunctional nanoparticle provides intriguing therapeutic promise as an effective and potent nanomedicine for the treatment of SHH MB.

Medulloblastoma cancer stem cells: molecular signatures and therapeutic targets

Medulloblastoma (MB) is the most common malignant primary intracranial neoplasm diagnosed in childhood. Although numerous efforts have been made during the past few years to exploit novel targeted therapies for this aggressive neoplasm, there still exist substantial hitches hindering successful management of MB. Lately, progress in cancer biology has shown evidence that a subpopulation of cells within the tumour, namely cancer stem cells (CSCs), are thought to be responsible for the resistance to most chemotherapeutic agents and radiation therapy, accounting for cancer recurrence. Hence, it is crucial to identify the molecular signatures and genetic aberrations that characterise those CSCs and develop therapies that specifically target them. In this review, we aim to give an overview of the main genetic and molecular cues that depict MB-CSCs and provide a synopsis of the novel therapeutic approaches that specifically target this population of cells to attain enhanced antitumorous effects and therefore overcome resistance to therapy.

Nanostructured Systems in Advanced Drug Targeting for the Cancer Treatment: Recent Patents

BACKGROUND

Cancer is one of the leading causes of death in the world and it is necessary to develop new strategies for its treatment because most therapies have limited access to many types of tumors, as well as low therapeutic efficacy and high toxicity.

OBJECTIVE

The present research aims to identify recent patents of drug delivery nanostructured systems that may have application in improving cancer treatment.

METHODS

Recent patents regarding the drug delivery nanostructured systems for cancer treatment were obtained from the patent databases of the six main patent offices of the world: United States Patent and Trademark Office, European Patent Office, World Intellectual Property Organization, Japan Patent Office, State Intellectual Property Office of China and Korean Intellectual Property Office.

RESULTS

A total of 1710 patent documents from 1998 to 2017 including "drug delivery nanostructured systems for cancer treatment" were retrieved. The top five countries in patent share were USA, China, South Korea, Canada and Germany. The universities and enterprises of USA had the highest amount of patents followed by institutions from China.

CONCLUSION

There is a strong tendency for the development of new nanostructured systems for the release of drugs; particularly, in recent years, the development of nanoparticles has focused on nanodiscs, gold nanoparticles and immunoliposomes.

Biomimetic Magnetic Nanostructures: A Theranostic Platform Targeting Lipid Metabolism and Immune Response in Lymphoma

B-cell lymphoma cells depend upon cholesterol to maintain pro-proliferation and pro-survival signaling via the B-cell receptor. Targeted cholesterol depletion of lymphoma cells is an attractive therapeutic strategy. We report here high-density lipoprotein mimicking magnetic nanostructures (HDL-MNSs) that can bind to the high-affinity HDL receptor, scavenger receptor type B1 (SR-B1), and interfere with cholesterol flux mechanisms in SR-B1 receptor positive lymphoma cells, causing cellular cholesterol depletion. In addition, the MNS core can be utilized for its ability to generate heat under an external radio frequency field. The thermal activation of MNS can lead to both innate and adaptive antitumor immune responses by inducing the expression of heat shock proteins that lead to activation of antigen presenting cells and finally lymphocyte trafficking. In the present study, we demonstrate SR-B1 receptor mediated binding and cellular uptake of HDL-MNS and prevention of phagolysosome formation by transmission electron microscopy, fluorescence microscopy, and ICP-MS analysis. The combinational therapeutics of cholesterol depletion and thermal activation significantly improves therapeutic efficacy in SR-B1 expressing lymphoma cells. HDL-MNS reduces the T₂ relaxation time under magnetic resonance imaging (MRI) more effectively compared with a commercially available contrast agent, and the specificity of HDL-MNS toward the SR-B1 receptor leads to differential contrast between SR-B1 positive and negative cells suggesting its utility in diagnostic imaging. Overall, we have demonstrated that HDL-MNSs have cell specific targeting efficiency, can modulate cholesterol efflux, can induce thermal activation mediated antitumor immune response, and possess high contrast under MRI, making it a promising theranostic platform in lymphoma.

Pharmacological mTOR targeting enhances the antineoplastic effects of selective PI3Kα inhibition in medulloblastoma

Despite recent advances in the treatment of medulloblastoma, patients in high-risk categories still face very poor outcomes. Evidence indicates that a subpopulation of cancer stem cells contributes to therapy resistance and tumour relapse in these patients. To prevent resistance and relapse, the development of treatment strategies tailored to target subgroup specific signalling circuits in high-risk medulloblastomas might be similarly important as targeting the cancer stem cell population. We have previously demonstrated potent antineoplastic effects for the PI3Kα selective inhibitor alpelisib in medulloblastoma. Here, we performed studies aimed to enhance the anti-medulloblastoma effects of alpelisib by simultaneous catalytic targeting of the mTOR kinase. Pharmacological mTOR inhibition potently enhanced the suppressive effects of alpelisib on cancer cell proliferation, colony formation and apoptosis and additionally blocked sphere-forming ability of medulloblastoma stem-like cancer cells in vitro. We identified the HH effector GLI1 as a target for dual PI3Kα and mTOR inhibition in SHH-type medulloblastoma and confirmed these results in HH-driven Ewing sarcoma cells. Importantly, pharmacologic mTOR inhibition greatly enhanced the inhibitory effects of alpelisib on medulloblastoma tumour growth in vivo. In summary, these findings highlight a key role for PI3K/mTOR signalling in GLI1 regulation in HH-driven cancers and suggest that combined PI3Kα/mTOR inhibition may be particularly interesting for the development of effective treatment strategies in high-risk medulloblastomas.

Targeting siRNA in colorectal cancer therapy: Nanotechnology comes into view

Colorectal cancer (CRC) is known as one of the most important causes of death and mortality worldwide. Although several efforts have been made for finding new therapies, no achievements have been made in this area. Multidrug resistance (MDR) mechanisms are one of the key factors that could lead to the failure of chemotherapy. Moreover, it has been shown that various chemotherapy drugs are associated with several side effects. Hence, it seems that finding new drugs or new therapeutic platforms is required. Among different therapeutic approaches, utilization of nanoparticles (NPs) for targeting a variety of molecules such as siRNAs are associated with good results for the treatment of CRC. Targeting siRNA-mediated NPs could turn off the effects of oncogenes and MDR-related genes. In the current study, we summarized various siRNAs targeted by NPs which could be used for the treatment of CRC. Moreover, we highlighted other routes such as liposome for targeting siRNAs in CRC therapy.

Role of cholesterol homeostasis and its efflux pathways in cancer progression

Tumor cells show high avidity for cholesterol in order to support their inherent nature to divide and proliferate. This results in the rewiring of cholesterol homeostatic pathways by influencing not only de novo synthesis but also uptake or efflux pathways of cholesterol. Recent findings have pointed towards the importance of cholesterol efflux in tumor pathogenesis. Cholesterol efflux is the first and foremost step in reverse cholesterol transport and any perturbation in this pathway may lead to the accumulation of intracellular cholesterol, thereby altering the cellular equilibrium. This review addresses the different mechanisms of cholesterol efflux from the cell and highlights their role and regulation in context to tumor development. There are four different routes by which cholesterol can be effluxed from the cell namely, 1) passive diffusion of cholesterol to mature HDL particles, 2) SR-B1 mediated facilitated diffusion, 3) Active efflux to apo A1 via ABCA1 and 4) ABCG1 mediated efflux to mature HDL. These molecular players facilitating cholesterol efflux are engaged in a complex interplay with different signaling pathways. Thus, an understanding of the efflux pathways, their regulation and cross-talk with signaling molecules may provide novel prognostic markers and therapeutic targets to combat the onset of carcinogenesis.

Potent Antineoplastic Effects of Combined PI3Kα-MNK Inhibition in Medulloblastoma

Medulloblastoma is a highly malignant pediatric brain tumor associated with poor outcome. Developing treatments that target the cancer stem cell (CSC) population in medulloblastoma are important to prevent tumor relapse and induce long-lasting clinical responses. We utilized medulloblastoma neurospheres that display CSC characteristics and found activation of the PI3K/AKT pathway in sphere-forming cells. Of all class IA PI3Ks, only the PI3Kα isoform was required for sphere formation by medulloblastoma cells. Knockdown of p110α, but not p110β or p110δ, significantly disrupted cancer stem cell frequencies as determined by extreme limiting dilution analysis (ELDA), indicating an essential role for the PI3Kα catalytic isoform in medulloblastoma CSCs. Importantly, pharmacologic inhibition of the MAPK-interacting kinase (MNK) enhanced the antineoplastic effects of targeted PI3Kα inhibition in medulloblastoma. This indicates that MNK signaling promotes survival in medulloblastoma, suggesting dual PI3Kα and MNK inhibition may provide a novel approach to target and eliminate medulloblastoma CSCs. We also observed a significant reduction in tumor formation in subcutaneous and intracranial mouse xenograft models, which further suggests that this combinatorial approach may represent an efficient therapeutic strategy for medulloblastoma. IMPLICATIONS: These findings raise the possibility of a unique therapeutic approach for medulloblastoma, involving MNK targeting to sensitize medulloblastoma CSCs to PI3Kα inhibition.

Precision Oncology in Sarcomas: Divide and Conquer

Sarcomas are a heterogeneous group of rare malignancies that exhibit remarkable heterogeneity, with more than 50 subtypes recognized. Advances in next-generation sequencing technology have resulted in the discovery of genetic events in these mesenchymal tumors, which in addition to enhancing understanding of the biology, have opened up avenues for molecularly targeted therapy and immunotherapy. This review focuses on how incorporation of next-generation sequencing has affected drug development in sarcomas and strategies for optimizing precision oncology for these rare cancers. In a significant percentage of soft tissue sarcomas, which represent up to 40% of all sarcomas, specific driver molecular abnormalities have been identified. The challenge to evaluate these mutations across rare cancer subtypes requires the careful characterization of these genetic alterations to further define compelling drivers with therapeutic implications. Novel models of clinical trial design also are needed. This shift would entail sustained efforts by the sarcoma community to move from one-size-fits-all trials, in which all sarcomas are treated similarly, to divide-and-conquer subtype-specific strategies.

Immunohistochemical Labeling of Low-Density Lipoprotein Receptor and Scavenger Receptor Class B Type 1 Are Increased in Canine Lymphoma

Altered lipid metabolism is a well-documented hallmark of neoplastic transformation and impacts disease progression. Two major lipoprotein receptors, the low-density lipoprotein receptor (LDL-R) and scavenger receptor class B, type 1 (SR-BI) are overexpressed in a number of cancer types in people. These receptors serve to deliver cholesterol to the tumor cells and have been used to target drug therapies. In this study, we performed a retrospective analysis of LDL-R and SR-B1 expression in canine lymphoma using archived formalin-fixed tissue samples. Cases were immunophenotyped and classified according to World Health Organization (WHO) standards prior to immunostaining for the LDL_R and SR-B1. A total of 45 cases were evaluated; 21 high grade B (HGB), 11 low grade B (LGB), 7 high grade T (HGT), and 6 low grade T (LGT) lymphomas. One sided Wilcoxon rank sum tests were used to compare staining intensity between neoplastic and hyperplastic lymphoid tissue. The relationships between histological score and tumor grade and score and stage at presentation were assessed using non-parametric Kruskal-Wallis tests. Neoplastic lymphoid tissue expressed higher levels of both receptors compared to reactive lymph nodes. Median LDL-R score was 85.0 (interquartile range = 101.7), Median SR-B1 score was 209.0 (interquartile range 105.2). No relationship between LDL-R or SR-B1 staining score and tumor grade or phenotype was found. Serum cholesterol concentration was compared between dogs with high and low grade tumors using a two sample T-test, and correlations between cholesterol concentration and histological score, and between the score for the two receptors were determined using a Spearman correlation. The high expression level of these lipoprotein receptors on most of the tumors could underlie the lack of relationship between score and tumor grade. The overexpression of LDL-R and SR-B1 in canine lymphoma holds therapeutic potential particularly in dogs that overexpress one or both of these receptors, and this warrants further investigation.