A strategy for combating melanoma with oncogenic c-Myc inhibitors and targeted nanotherapy

Follow-up Comparisons of Two Plasma Biomarkers of Alzheimer's Disease, Neurofilament Light Chain, and Oligomeric Aβ: A Pilot Study

BACKGROUND AND OBJECTIVE

Recent evidence suggests that blood-based biomarkers might be useful for Alzheimer's disease (AD). Among them, we intend to investigate whether neurofilament light (NfL) and multimer detection system-oligomeric Aβ (MDS-OAβ) values can be useful in screening, predicting, and monitoring disease progression and how the relationship between NfL and MDS-OAβ values changes.

METHODS

Eighty participants with probable AD dementia, 50 with mild cognitive impairment (MCI), and 19 with subjective cognitive decline (SCD) underwent baseline and follow-up evaluations of the Mini-Mental Status Examination (MMSE) and both plasma biomarkers.

RESULTS

Baseline MDS-OAß (p = 0.016) and NfL (p = 0.002) plasma concentrations differed significantly among groups, but only NfL correlated with baseline MMSE scores (r = -0.278, p = 0.001). In follow-up, neither correlated with MMSE changes overall. However, in SCD and MCI participants (n = 32), baseline MDS-OAß correlated with follow-up MMSE scores (r = 0.532, p = 0.041). Linear regression revealed a relationship between baseline MDS-OAβ and follow-up MMSE scores. In SCD and MCI participants, plasma NfL changes correlated with MMSE changes (r = 0.564, p = 0.028).

CONCLUSION

This study shows that only in participants with SCD and MCI, not including AD dementia, can MDS-OAß predict the longitudinal cognitive decline measured by follow-up MMSE. Changes of NfL, not MDS-OAß, parallel the changes of MMSE. Further studies with larger samples and longer durations could strengthen these results..

An Osimertinib-Perfluorocarbon Nanoemulsion with Excellent Targeted Therapeutic Efficacy in Non-small Cell Lung Cancer: Achieving Intratracheal and Intravenous Administration

Low accumulation of anticancer drugs in tumors and serious systemic toxicity remain the main challenges to the clinical efficiency of pharmaceuticals. Pulmonary delivery of nanoscale-based drug delivery systems offered a strategy to increase antitumor activity with minimal adverse exposure. Herein, we report an osimertinib-loaded perfluoro-15-crown-5-ether (AZD9291-PFCE) nanoemulsion, through intratracheal and intravenous delivery, synergizes with ¹⁹F magnetic resonance imaging (¹⁹F MRI)-guided low-intensity focused ultrasound (LIFU) for lung cancer therapy. Pulmonary delivery of AZD9291-PFCE nanoemulsion in orthotopic lung carcinoma models achieves quick distribution of the nanoemulsion in lung tissues and tumors without short-term and long-term toxic effects. Furthermore, LIFU can trigger drug release from the AZD9291-PFCE nanoemulsion and specifically increases tumor vascular and tumor tissue permeability. ¹⁹F MRI was applied to quantify nanoemulsion accumulation in tumors in real time after LIFU irradiation. We validate the treatment effect of AZD9291-PFCE nanoemulsion in resected human lung cancer tissues, proving the translational potential to enhance clinical outcomes of lung cancer therapy. Thus, this work presents a promising pulmonary nanoemulsion delivery system of osimertinib (AZD9291) for targeted therapy of lung cancer without severe side effects.

The Amyloid-β Pathway in Alzheimer's Disease

Breakthroughs in molecular medicine have positioned the amyloid-β (Aβ) pathway at the center of Alzheimer's disease (AD) pathophysiology. While the detailed molecular mechanisms of the pathway and the spatial-temporal dynamics leading to synaptic failure, neurodegeneration, and clinical onset are still under intense investigation, the established biochemical alterations of the Aβ cycle remain the core biological hallmark of AD and are promising targets for the development of disease-modifying therapies. Here, we systematically review and update the vast state-of-the-art literature of Aβ science with evidence from basic research studies to human genetic and multi-modal biomarker investigations, which supports a crucial role of Aβ pathway dyshomeostasis in AD pathophysiological dynamics. We discuss the evidence highlighting a differentiated interaction of distinct Aβ species with other AD-related biological mechanisms, such as tau-mediated, neuroimmune and inflammatory changes, as well as a neurochemical imbalance. Through the lens of the latest development of multimodal in vivo biomarkers of AD, this cross-disciplinary review examines the compelling hypothesis- and data-driven rationale for Aβ-targeting therapeutic strategies in development for the early treatment of AD.

Anti-c-myc RNAi-Based Onconanotherapeutics

Overexpression of the c-myc proto-oncogene features prominently in most human cancers. Early studies established that inhibiting the expression of oncogenic c-myc, produced potent anti-cancer effects. This gave rise to the notion that an appropriate c-myc silencing agent might provide a broadly applicable and more effective form of cancer treatment than is currently available. The endogenous mechanism of RNA interference (RNAi), through which small RNA molecules induce gene silencing by binding to complementary mRNA transcripts, represents an attractive avenue for c-myc inhibition. However, the development of a clinically viable, anti-c-myc RNAi-based platform is largely dependent upon the design of an appropriate carrier of the effector nucleic acids. To date, organic and inorganic nanoparticles were assessed both in vitro and in vivo, as carriers of small interfering RNA (siRNA), DICER-substrate siRNA (DsiRNA), and short hairpin RNA (shRNA) expression plasmids, directed against the c-myc oncogene. We review here the various anti-c-myc RNAi-based nanosystems that have come to the fore, especially between 2005 and 2020.

Nanotherapy delivery of c-myc inhibitor targets Protumor Macrophages and preserves Antitumor Macrophages in Breast Cancer

Tumor-associated macrophages (TAMs) enhance tumor growth in mice and are correlated with a worse prognosis for breast cancer patients. While early therapies sought to deplete all macrophages, current therapeutics aim to reprogram pro-tumor macrophages (M2) and preserve those necessary for anti-tumor immune responses (M1). Recent studies have shown that c-MYC (MYC) is induced in M2 macrophages in vitro and in vivo where it regulates the expression of tumor-promoting genes. In a myeloid lineage MYC KO mouse model, MYC had important roles in macrophage maturation and function leading to reduced tumor growth. We therefore hypothesized that targeted delivery of a MYC inhibitor to established M2 TAMs could reduce polarization toward an M2 phenotype in breast cancer models.

Methods: In this study, we developed a MYC inhibitor prodrug (MI3-PD) for encapsulation within perfluorocarbon nanoparticles, which can deliver drugs directly to the cytosol of the target cell through a phagocytosis independent mechanism. We have previously shown that M2-like TAMs express significant levels of the vitronectin receptor, integrin β3, and in vivo targeting and therapeutic potential was evaluated using αvβ3 integrin targeted rhodamine-labeled nanoparticles (NP) or integrin αvβ3-MI3-PD nanoparticles.

Results: We observed that rhodamine, delivered by αvβ3-rhodamine NP, was incorporated into M2 tumor promoting macrophages through both phagocytosis-independent and dependent mechanisms, while NP uptake in tumor suppressing M1 macrophages was almost exclusively through phagocytosis. In a mouse model of breast cancer (4T1-GFP-FL), M2-like TAMs were significantly reduced with αvβ3-MI3-PD NP treatment. To validate this effect was independent of drug delivery to tumor cells and was specific to the MYC inhibitor, mice with integrin β3 knock out tumors (PyMT-Bo1 β3KO) were treated with αvβ3-NP or αvβ3-MI3-PD NP. M2 macrophages were significantly reduced with αvβ3-MI3-PD nanoparticle therapy but not αvβ3-NP treatment.

Conclusion: These data suggest αvβ3-NP-mediated drug delivery of a c-MYC inhibitor can reduce protumor M2-like macrophages while preserving antitumor M1-like macrophages in breast cancer.

Blood amyloid-β oligomerization associated with neurodegeneration of Alzheimer's disease

Introduction

Oligomeric amyloid-ß is a major toxic species associated with Alzheimer’s disease pathogenesis. Methods used to measure oligomeric amyloid-β in the blood have increased in number in recent years. The Multimer Detection System-Oligomeric Amyloid-β (MDS-OAβ) is a specific method to measure oligomerization tendencies in the blood. The objective of this study was to determine the association between amyloid-ß oligomerization in the plasma and structural changes of the brain.

Methods

We studied 162 subjects composed of 92 community-based normal healthy subjects, 17 with subjective cognitive decline, 14 with mild cognitive impairment and 39 with Alzheimer’s disease dementia. All subjects underwent MDS-OAβ and three-dimensional T1 magnetic resonance imaging. To determine the structural changes of the brain that are statistically correlated with MDS-OAβ level, we used voxel-based morphometry with corrections for age and total intracranial volume covariates.

Results

We found brain volume reduction in the bilateral temporal, amygdala, parahippocampal and lower parietal lobe and left cingulate and precuneus regions (family-wise error, p < 0.05). Reduction was also found in white matter in proximity to the left temporal and bilateral lower parietal lobes and posterior corpus callosum (family-wise error, p < 0.05). Brain volume increment was not observed in any regions within grey or white matter.

Discussion

Findings suggest that substantial correlation exists between amyloid ß oligomerization in the blood and brain volume reduction in the form of Alzheimer’s disease despite of uncertainty in the casual relationship.

Electronic supplementary material

The online version of this article (10.1186/s13195-019-0499-7) contains supplementary material, which is available to authorized users.

Metabolomic identification of diagnostic serum-based biomarkers for advanced stage melanoma

INTRODUCTION

Melanoma is a highly aggressive malignancy and is currently one of the fastest growing cancers worldwide. While early stage (I and II) disease is highly curable with excellent prognosis, mortality rates rise dramatically after distant spread. We sought to identify differences in the metabolome of melanoma patients to further elucidate the pathophysiology of melanoma and identify potential biomarkers to aid in earlier detection of recurrence.

METHODS

Using ¹H NMR and DI-LC-MS/MS, we profiled serum samples from 26 patients with stage III (nodal metastasis) or stage IV (distant metastasis) melanoma and compared their biochemical profiles with 46 age- and gender-matched controls.

RESULTS

We accurately quantified 181 metabolites in serum using a combination of ¹H NMR and DI-LC-MS/MS. We observed significant separation between cases and controls in the PLS-DA scores plot (permutation test p-value = 0.002). Using the concentrations of PC-aa-C40:3, DL-carnitine, octanoyl-L-carnitine, ethanol, and methylmalonyl-L-carnitine we developed a diagnostic algorithm with an AUC (95% CI) = 0.822 (0.665-0.979) with sensitivity and specificity of 100 and 56%, respectively. Furthermore, we identified arginine, proline, tryptophan, glutamine, glutamate, glutathione and ornithine metabolism to be significantly perturbed due to disease (p < 0.05).

CONCLUSION

Targeted metabolomic analysis demonstrated significant differences in metabolic profiles of advanced stage (III and IV) melanoma patients as compared to controls. These differences may represent a potential avenue for the development of multi-marker serum-based assays for earlier detection of recurrences, allow for newer, more effective targeted therapy when tumor burden is less, and further elucidate the pathophysiologic changes that occur in melanoma.

Plasma Oligomeric Beta Amyloid in Alzheimer's Disease with History of Agent Orange Exposure

BACKGROUND AND PURPOSE

During the Vietnam War, many Korean soldiers were exposed to Agent Orange. Until now, there existed only limited evidence of association between exposure to Agent Orange and Alzheimer's disease (AD). The main pathological feature of AD is brain amyloidosis. To explore the pathophysiological characteristic of AD with Agent Orange exposure, we compared newly developed amyloid beta (Aβ) oligomer levels in plasma between AD with Agent Orange exposure and without exposure.

METHODS

We recruited 48 AD patients with Agent Orange exposure and 66 AD patients without Agent Orange. Using the Multimer Detection System technique, which was based on an enzyme-linked immunosorbent assay, we measured Aβ oligomers in the plasma of study subjects.

RESULTS

Compared to normal control patients, plasma Aβ oligomer levels were higher in AD patients regardless of history of Agent Orange exposure. However, AD patients with Agent Orange exposure showed higher plasma Aβ oligomer levels than AD patients without Agent Orange.

DISCUSSION

This study showed higher plasma Aβ oligomer levels in AD patients with Agent Orange exposure compared to AD patients without Agent Orange. This finding suggests the possibility of a different pathophysiology of AD patients with Agent Orange exposure from AD patients without Agent Orange.

Perfluorooctylbromide nanoparticles for ultrasound imaging and drug delivery

Perfluorooctylbromide nanoparticles (PFOB NPs) are a type of multifunctional nanotechnology that has been studied for various medical applications. Commercial ultrasound contrast agents (UCAs) suffer from the following limitations: short half-lives in vivo, high background signal and restricted distribution in the vascular circulation due to their micrometer dimensions. PFOB NPs are new potential UCAs that persist for long periods in the circulatory system, possess a relatively stable echogenic response without increasing the background signal and exhibit lower acoustic attenuation than commercial UCAs. Furthermore, PFOB NPs may also serve as drug delivery vehicles in which drugs are dissolved in the outer lipid or polymer layer for subsequent delivery to target sites in site-targeted therapy. The use of PFOB NPs as carriers has the potential advantage of selectively delivering payloads to the target site while improving visualization of the site using ultrasound (US) imaging. Unfortunately, the application of PFOB NPs to the field of ultrasonography has been limited because of the low intensity of US reflection. Numerous researchers have realized the potential use of PFOB NPs as UCAs and thus have developed alternative approaches to apply PFOB NPs in ultrasonography. In this article, we review the latest approaches for using PFOB NPs to enhance US imaging in vivo. In addition, this article emphasizes the application of PFOB NPs as promising drug delivery carriers for cancer and atherosclerosis treatments, as PFOB NPs can transport different drug payloads for various applications with good efficacy. We also note the challenges and future study directions for the application of PFOB NPs as both a delivery system for therapeutic agents and a diagnostic agent for ultrasonography.

Nano-Assembly of Pamitoyl-Bioconjugated Coenzyme-A for Combinatorial Chemo-Biologics in Transcriptional Therapy

Pathogenesis, the biological mechanism that leads to the diseased state, of many cancers is driven by interruptions to the role of Myc oncoprotein, a regulator protein that codes for a transcription factor. One of the most significant biological interruptions to Myc protein is noted as its dimerization with Max protein, another important factor of family of transcription factors. Binding of this heterodimer to E-Boxes, enhancer boxes as DNA response element found in some eukaryotes that act as a protein-binding site and have been found to regulate gene expression, are interrupted to regulate cancer pathogenesis. The systemic effectiveness of potent small molecule inhibitors of Myc-Max dimerization has been limited by poor bioavailability, rapid metabolism, and inadequate target site penetration. The potential of gene therapy for targeting Myc can be fully realized by successful synthesis of a smart cargo. We developed a "nuclein" type nanoparticle "siNozyme" (45 ± 5 nm) from nanoassembly of pamitoyl-bioconjugated acetyl coenzyme-A for stable incorporation of chemotherapeutics and biologics to achieve remarkable growth inhibition of human melanoma. Results indicated that targeting transcriptional gene cMyc with siRNA with codelivery of a topoisomerase inhibitor, amonafide caused ∼90% growth inhibition and 95% protein inhibition.

Radionuclides transform chemotherapeutics into phototherapeutics for precise treatment of disseminated cancer

Most cancer patients succumb to disseminated disease because conventional systemic therapies lack spatiotemporal control of their toxic effects in vivo, particularly in a complicated milieu such as bone marrow where progenitor stem cells reside. Here, we demonstrate the treatment of disseminated cancer by photoactivatable drugs using radiopharmaceuticals. An orthogonal-targeting strategy and a contact-facilitated nanomicelle technology enabled highly selective delivery and co-localization of titanocene and radiolabelled fluorodeoxyglucose in disseminated multiple myeloma cells. Selective ablation of the cancer cells was achieved without significant off-target toxicity to the resident stem cells. Genomic, proteomic and multimodal imaging analyses revealed that the downregulation of CD49d, one of the dimeric protein targets of the nanomicelles, caused therapy resistance in small clusters of cancer cells. Similar treatment of a highly metastatic breast cancer model using human serum albumin-titanocene formulation significantly inhibited cancer growth. This strategy expands the use of phototherapy for treating previously inaccessible metastatic disease.

Co-coating of receptor-targeted drug nanocarriers with anti-phagocytic moieties enhances specific tissue uptake versus non-specific phagocytic clearance

Nanocarriers (NCs) help improve the performance of therapeutics, but their removal by phagocytes in the liver, spleen, tissues, etc. diminishes this potential. Although NC functionalization with polyethylene glycol (PEG) lowers interaction with phagocytes, it also reduces interactions with tissue cells. Coating NCs with CD47, a protein expressed by body cells to avoid phagocytic removal, offers an alternative. Previous studies showed that coating CD47 on non-targeted NCs reduces phagocytosis, but whether this alters binding and endocytosis of actively-targeted NCs remains unknown. To evaluate this, we used polymer NCs targeted to ICAM-1, a receptor overexpressed in many diseases. Co-coating of CD47 on anti-ICAM NCs reduced macrophage phagocytosis by ∼50% for up to 24 h, while increasing endothelial-cell targeting by ∼87% over control anti-ICAM/IgG NCs. Anti-ICAM/CD47 NCs were endocytosed via the CAM-mediated pathway with efficiency similar (0.99-fold) to anti-ICAM/IgG NCs. Comparable outcomes were observed for NCs targeted to PECAM-1 or transferrin receptor, suggesting broad applicability. When injected in mice, anti-ICAM/CD47 NCs reduced liver and spleen uptake by ∼30-50% and increased lung targeting by ∼2-fold (∼10-fold over IgG NCs). Therefore, co-coating NCs with CD47 and targeting moieties reduces macrophage phagocytosis and improves targeted uptake. This strategy may significantly improve the efficacy of targeted drug NCs.

SIRT1 regulates Mxd1 during malignant melanoma progression

In a murine melanoma model, malignant transformation promoted by a sustained stress condition was causally related to increased levels of reactive oxygen species resulting in DNA damage and massive epigenetic alterations. Since the chromatin modifier Sirtuin-1 (SIRT1) is a protein attracted to double-stranded DNA break (DSB) sites and can recruit other components of the epigenetic machinery, we aimed to define the role of SIRT1 in melanomagenesis through our melanoma model. The DNA damage marker, γH2AX was found increased in melanocytes after 24 hours of deadhesion, accompanied by increased SIRT1 expression and decreased levels of its target, H4K16ac. Moreover, SIRT1 started to be associated to DNMT3B during the stress condition, and this complex was maintained along malignant progression. Mxd1 was identified by ChIP-seq among the DNA sequences differentially associated with SIRT1 during deadhesion and was shown to be a common target of both, SIRT1 and DNMT3B. In addition, Mxd1 was found downregulated from pre-malignant melanocytes to metastatic melanoma cells. Treatment with DNMT inhibitor 5AzaCdR reversed the Mxd1 expression. Sirt1 stable silencing increased Mxd1 mRNA expression and led to down-regulation of MYC targets, such as Cdkn1a, Bcl2 and Psen2, whose upregulation is associated with human melanoma aggressiveness and poor prognosis. We demonstrated a novel role of the stress responsive protein SIRT1 in malignant transformation of melanocytes associated with deadhesion. Mxd1 was identified as a new SIRT1 target gene. SIRT1 promoted Mxd1 silencing, which led to increased activity of MYC oncogene contributing to melanoma progression.

Targeted therapy of octreotide-modified oleanolic acid liposomes to somatostatin receptor overexpressing tumor cells

AIM

To prepare and validate the efficacy of a novel targeted drug delivery system - octreotide (Oct)-modified oleanolic acid (OA) liposomes.

MATERIALS & METHODS

OA liposomes (OA-L) were prepared by an ethanol injection method. The Oct-modified OA liposomes (O-OA-L) were synthesized and their properties were evaluated. Cellular uptake and competition inhibition studies were performed.

RESULTS

The OA vesicles presented satisfactory particles size (100-200 nm), stability and drug release characteristics; their ζ potential was -1.42 ± 0.08 mV. The O-OA-L had a higher cell proliferation inhibitory activity and cellular uptake than that of OA-L for somatostatin receptor-positive A549 cells.

CONCLUSION

The O-OA-L, as a promising agent, can target actively the lesion site with safe and high-efficiency pattern.

Development and characterization of resveratrol nanoemulsions carrying dual-imaging agents

AIM

Delivery of the natural anti-inflammatory compound resveratrol with nanoemulsions can dramatically improve its tissue targeting, bioavailability and efficacy. Current assessment of resveratrol delivery efficacy is limited to indirect pharmacological measures. Molecular imaging solves this problem. Results/methodology: Nanoemulsions containing two complementary imaging agents, near-infrared dye and perfluoropolyether (PFPE), were developed and evaluated. Nanoemulsion effects on macrophage uptake, toxicity and NO production were also evaluated. The presence of PFPE did not affect nanoemulsion size, zeta potential, colloidal stability, drug loading or drug release.

CONCLUSION

PFPE nanoemulsions can be used in future studies to evaluate nanoemulsion biodistribution without interfering with resveratrol delivery and pharmacological outcomes. Developed nanoemulsions show promise as a versatile treatment strategy for cancer and other inflammatory diseases. [Formula: see text].

Droplet-based magnetic bead immunoassay using microchannel-connected multiwell plates (μCHAMPs) for the detection of amyloid beta oligomers

Multiwell plates are regularly used in analytical research and clinical diagnosis but often require laborious washing steps and large sample or reagent volumes (typically, 100 μL per well). To overcome such drawbacks in the conventional multiwell plate, we present a novel microchannel-connected multiwell plate (μCHAMP) that can be used for automated disease biomarker detection in a small sample volume by performing droplet-based magnetic bead immunoassay inside the plate. In this μCHAMP-based immunoassay platform, small volumes (30-50 μL) of aqueous-phase working droplets are stably confined within each well by the simple microchannel structure (200-300 μm in height and 0.5-1 mm in width), and magnetic beads are exclusively transported into an adjacent droplet through the oil-filled microchannels assisted by a magnet array aligned beneath and controlled by a XY-motorized stage. Using this μCHAMP-based platform, we were able to perform parallel detection of synthetic amyloid beta (Aβ) oligomers as a model analyte for the early diagnosis of Alzheimer's disease (AD). This platform easily simplified the laborious and consumptive immunoassay procedure by achieving automated parallel immunoassay (32 assays per operation in 3-well connected 96-well plate) within 1 hour and at low sample consumption (less than 10 μL per assay) with no cumbersome manual washing step. Moreover, it could detect synthetic Aβ oligomers even below 10 pg mL(-1) concentration with a calculated detection limit of ∼3 pg mL(-1). Therefore, the μCHAMP and droplet-based magnetic bead immunoassay, with the combination of XY-motorized magnet array, would be a useful platform in the diagnosis of human disease, including AD, which requires low consumption of the patient's body fluid sample and automation of the entire immunoassay procedure for high processing capacity.

Time-staggered delivery of docetaxel and H1-S6A,F8A peptide for sequential dual-strike chemotherapy through tumor priming and nuclear targeting

While highly effective for slowing cancer progression in principle, the c-Myc inhibitor peptide H1-S6A,F8A (H1) has not performed well in tumor studies, in part because it does not pass efficiently through the nuclear envelope. Here we describe a dual-strike strategy in which tumor cells were treated first with N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-docetaxel (DTX) conjugates (P-DTX), which arrested cells in the G2/M phase and prolonged the period when the nuclear membrane was disassembled. In the second strike, the cells were then treated with P-H1 conjugates, which entered the nucleus and efficiently inhibited c-Myc. The in vitro studies demonstrated that the combination of P-DTX and P-H1 conjugates was sequence-dependent, and P-DTX followed by P-H1 had synergism, which was significantly more effective than reverse sequential delivery, simultaneous co-delivery or monotherapy with P-DTX or P-H1 alone. The in vivo studies showed that sequential delivery of P-DTX followed by P-H1 remarkably slowed the tumor growth and improved the animal survival. This sequential, dual-strike approach provides new opportunities for nuclear-targeted anticancer drug delivery.

Contact-facilitated drug delivery with Sn2 lipase labile prodrugs optimize targeted lipid nanoparticle drug delivery

Sn2 lipase labile phospholipid prodrugs in conjunction with contact-facilitated drug delivery offer an important advancement in Nanomedicine. Many drugs incorporated into nanosystems, targeted or not, are substantially lost during circulation to the target. However, favorably altering the pharmacokinetics and volume of distribution of systemic drug delivery can offer greater efficacy with lower toxicity, leading to new prolonged-release nanoexcipients. However, the concept of achieving Paul Erhlich's inspired vision of a 'magic bullet' to treat disease has been largely unrealized due to unstable nanomedicines, nanosystems achieving low drug delivery to target cells, poor intracellular bioavailability of endocytosed nanoparticle payloads, and the substantial biological barriers of extravascular particle penetration into pathological sites. As shown here, Sn2 phospholipid prodrugs in conjunction with contact-facilitated drug delivery prevent premature drug diffusional loss during circulation and increase target cell bioavailability. The Sn2 phospholipid prodrug approach applies equally well for vascular constrained lipid-encapsulated particles and micelles the size of proteins that penetrate through naturally fenestrated endothelium in the bone marrow or thin-walled venules of an inflamed microcirculation. At one time Nanomedicine was considered a 'Grail Quest' by its loyal opposition and even many in the field adsorbing the pains of a long-learning curve about human biology and particles. However, Nanomedicine with innovations like Sn2 phospholipid prodrugs has finally made 'made the turn' toward meaningful translational success.

The overriding of TRAIL resistance by the histone deacetylase inhibitor MS-275 involves c-myc up-regulation in cutaneous, uveal, and mucosal melanoma

Malignant melanoma is a highly aggressive tumor which may occur in the skin, eye, and mucous membranes. The prognosis of melanoma remains poor in spite of therapeutic advances, emphasizing the importance of innovative treatment modalities. Currently, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is showing promising clinical responses, however its use is hampered by intrinsic or acquired melanoma resistance to apoptosis. Recently, we showed that the combination of TRAIL with the class I-specific histone deacetylase inhibitor (HDACi) MS-275 was a privileged way to override TRAIL resistance through down-regulation of cellular Fas-associated death domain (FADD)-like interleukin-1beta-converting enzyme-inhibitory protein (c-FLIP). Here, we elucidated the underlying mechanism and provided evidence that a crucial step in the c-FLIP downregulation triggered by MS-275 implies the up-regulation of c-myc, a transcriptional repressor of c-FLIP. Notably, MS-275 caused H3 histone acetylation at the promoter of c-myc and increased its binding to the c-FLIP promoter, that in turn led to reduced c-FLIP gene transcription. Knockdown of c-myc prevented the MS-275-mediated downregulation of c-FLIP and hindered TRAIL-plus MS-275-induced apoptosis. Findings reported here provide additional knowledge tools for a more aware and effective molecular therapy of melanoma.

Small Molecule MYC Inhibitor Conjugated to Integrin-Targeted Nanoparticles Extends Survival in a Mouse Model of Disseminated Multiple Myeloma

Multiple myeloma pathogenesis is driven by the MYC oncoprotein, its dimerization with MAX, and the binding of this heterodimer to E-Boxes in the vicinity of target genes. The systemic utility of potent small molecule inhibitors of MYC-MAX dimerization was limited by poor bioavailability, rapid metabolism, and inadequate target site penetration. We hypothesized that new lipid-based MYC-MAX dimerization inhibitor prodrugs delivered via integrin-targeted nanoparticles (NP) would overcome prior shortcomings of MYC inhibitor approaches and prolong survival in a mouse model of cancer. An Sn 2 lipase-labile prodrug inhibitor of MYC-MAX dimerization (MI1-PD) was developed which decreased cell proliferation and induced apoptosis in cultured multiple myeloma cell lines alone (P < 0.05) and when incorporated into integrin-targeted lipid-encapsulated NPs (P < 0.05). Binding and efficacy of NPs closely correlated with integrin expression of the target multiple myeloma cells. Using a KaLwRij metastatic multiple myeloma mouse model, VLA-4-targeted NPs (20 nm and 200 nm) incorporating MI1-PD (D) NPs conferred significant survival benefits compared with respective NP controls, targeted (T) no-drug (ND), and untargeted (NT) control NPs (T/D 200: 46 days vs.

NT/ND

28 days, P < 0.05 and T/D 20: 52 days vs.

NT/ND

29 days, P = 0.001). The smaller particles performed better of the two sizes. Neither MI1 nor MI1-PD provided survival benefit when administered systemically as free compounds. These results demonstrate for the first time that a small molecule inhibitor of the MYC transcription factor can be an effective anticancer agent when delivered using a targeted nanotherapy approach.