Gemcitabine elaidate and ONC201 combination therapy for inhibiting pancreatic cancer in a KRAS mutated syngeneic mouse model

Approximately 90% of pancreatic cancer (PC) contain KRAS mutations. Mutated KRAS activates the downstream oncogenic PI3K/AKT and MEK signaling pathways and induces drug resistance. However, targeting both pathways with different drugs can also lead to excessive toxicity. ONC201 is a dual PI3K/AKT and MEK pathway inhibitor with an excellent safety profile that targets death receptor 5 (DR5) to induce apoptosis. Gemcitabine (GEM) is a first-line chemotherapy in PC, but it is metabolically unstable and can be stabilized by a prodrug approach. In this study, phospho-Akt, phospho-mTOR, and phospho-ERK protein expressions were evaluated in patient PDAC-tissues (n = 10). We used lipid-gemcitabine (L_GEM) conjugate, which is more stable and enters the cells by passive diffusion. Further, we evaluated the efficacy of L_GEM and ONC201 in PC cells and "KrasLSL-G12D; p53LoxP; Pdx1-CreER (KPC) triple mutant xenograft tumor-bearing mice. PDAC patient tissues showed significantly higher levels of p-AKT (Ser473), p-ERK (T202/T204), and p-mTOR compared to surrounding non-cancerous tissues. ONC201 in combination with L_GEM, showed a superior inhibitory effect on the growth of MIA PaCa-2 cells. In our in-vivo study, we found that ONC201 and L_GEM combination prevented neoplastic proliferation via AKT/ERK blockade to overcome chemoresistance and increased T-cell tumor surveillance. Simultaneous inhibition of the PI3K/AKT and MEK pathways with ONC201 is an attractive approach to potentiate the effect of GEM. Our findings provide insight into rational-directed precision chemo and immunotherapy therapy in PDAC.

Recent advances in drug delivery and targeting for the treatment of pancreatic cancer

Despite significant treatment efforts, pancreatic ductal adenocarcinoma (PDAC), the deadliest solid tumor, is still incurable in the preclinical stages due to multifacet stroma, dense desmoplasia, and immune regression. Additionally, tumor heterogeneity and metabolic changes are linked to low grade clinical translational outcomes, which has prompted the investigation of the mechanisms underlying chemoresistance and the creation of effective treatment approaches by selectively targeting genetic pathways. Since targeting upstream molecules in first-line oncogenic signaling pathways typically has little clinical impact, downstream signaling pathways have instead been targeted in both preclinical and clinical studies. In this review, we discuss how the complexity of various tumor microenvironment (TME) components and the oncogenic signaling pathways that they are connected to actively contribute to the development and spread of PDAC, as well as the ways that recent therapeutic approaches have been targeted to restore it. We also illustrate how many endogenous stimuli-responsive linker-based nanocarriers have recently been developed for the specific targeting of distinct oncogenes and their downstream signaling cascades as well as their ongoing clinical trials. We also discuss the present challenges, prospects, and difficulties in the development of first-line oncogene-targeting medicines for the treatment of pancreatic cancer patients.

Natural killer cells for pancreatic cancer immunotherapy: Role of nanoparticles

Advanced pancreatic cancer patients have a dismal prognosis despite advances in integrative therapy. The field of tumor immunology has witnessed significant advancements for cancer treatment. However, immunotherapy for pancreatic cancer is not very effective due to its highly complex tumor microenvironment (TME). Natural killer (NK) cells are lymphocytes that play an important role in the innate immune system. NK cells do not require antigen pre-sensitization, nor are they confined by the major histocompatibility complex (MHC). NK cells have the potential to eliminate cancer cells through CAR-dependent and CAR-independent pathways, demonstrating reduced levels of systemic toxicity in the process. The availability of several potential sources of NK cells is an additional benefit that contributes to meeting the therapeutic criteria. Adding nanotechnology to enhance the functions of effector NK cells is also an appealing strategy. This article primarily discusses various approaches recently been utilized to enhance the NK functions for the treatment of pancreatic cancer. In addition, new advances in boosting NK cell therapeutic efficacy by nanoparticle mediation are presented, with a focus on pancreatic cancer.

Anti-miR-96 and Hh pathway inhibitor MDB5 synergistically ameliorate alcohol-associated liver injury in mice

Alcohol-associated liver disease (ALD) and its complications are significant health problems worldwide. Several pathways in ALD are influenced by alcohol that drives inflammation, fatty acid metabolism, and fibrosis. Although miR-96 has become a key regulator in several liver diseases, its function in ALD remains unclear. In contrast, sonic hedgehog (SHH) signaling has a well-defined role in liver disease through influencing the activation of hepatic stellate cells (HSCs) and the inducement of liver fibrosis. In this study, we investigated the expression patterns of miR-96 and Hh molecules in mouse and human liver samples. We showed that miR-96 and Shh were upregulated in ethanol-fed mice. Furthermore, alcoholic hepatitis (AH) patient specimens also showed upregulated FOXO3a, TGF-β1, SHH, and GLI2 proteins. We then examined the effects of Hh inhibitor MDB5 and anti-miR-96 on inflammatory and extracellular matrix (ECM)-related genes. We identified FOXO3 and SMAD7 as direct target genes of miR-96. Inhibition of miR-96 decreased the expression of these genes in vitro in AML12 cells, HSC-T6 cells, and in vivo in ALD mice. Furthermore, MDB5 decreased HSCs activation and the expression of ECM-related genes, such as Gli1, Tgf-β1, and collagen. Lipid nanoparticles (LNPs) loaded with the combination of MDB5, and anti-miR-96 ameliorated ALD in mice. Our study demonstrated that this combination therapy could serve as a new therapeutic target for ALD.

Targeting BRD4 and PI3K signaling pathways for the treatment of medulloblastoma

Medulloblastoma (MB) is a malignant pediatric brain tumor which shows upregulation of MYC and sonic hedgehog (SHH) signaling. SHH inhibitors face acquired resistance, which is a major cause of relapse. Further, direct MYC oncogene inhibition is challenging, inhibition of MYC upstream insulin-like growth factor/ phosphatidylinositol-4,5-bisphosphate 3-kinase (IGF/PI3K) is a promising alternative. While PI3K inhibition activates resistance mechanisms, simultaneous inhibition of bromodomain-containing protein 4 (BRD4) and PI3K can overcome resistance. We synthesized a new molecule 8-(2,3-dihydrobenzo[b] [1, 4] dioxin-6-yl)-2-morpholino-4H-chromen-4-one (MDP5) that targets both BRD4 and PI3K pathways. We used X-ray crystal structures and a molecular modeling approach to confirm the interactions between MDP5 with bromo domains (BDs) from both BRD2 and BRD4, and molecular modeling for PI3K binding. MDP5 was shown to inhibit target pathways and MB cell growth in vitro and in vivo. MDP5 showed higher potency in DAOY cells (IC50 5.5 μM) compared to SF2523 (IC50 12.6 μM), and its IC50 values in HD-MB03 cells were like SF2523. Treatment of MB cells with MDP5 significantly decreased colony formation, increased apoptosis, and halted cell cycle progression. Further, MDP5 was well tolerated in NSG mice bearing either xenograft or orthotopic MB tumors at the dose of 20 mg/kg, and significantly reduced tumor growth and prolonged animal survival.

pH-sensitive nanomedicine of novel tubulin polymerization inhibitor for lung metastatic melanoma

Microtubule binding agents such as paclitaxel and vincristine have activity in metastatic melanoma. However, even responsive tumors develop resistance, highlighting the need to investigate new drug molecules. Here, we showed that a new compound, CH-2-102, developed by our group, has high anti-tumor efficacy in human and murine melanoma cells. We confirmed that CH-2-102 robustly suppresses the microtubule polymerization process by directly interacting with the colchicine binding site. Our results unveil that CH-2-102 suppresses microtubule polymerization and subsequently induces G2 phase cell arrest as one of the possible mechanisms. Notably, CH-2-102 maintains its efficacy even in the paclitaxel resistance melanoma cells due to different binding sites and a non-Pgp substrate. We developed a pH-responsive drug-polymer Schiff bases linker for high drug loading into nanoparticles (NPs). Our CH-2-102 conjugated NPs induced tumor regression more effectively than Abraxane® (Nab-paclitaxel, N-PTX), free drug, and non-sensitive NPs in B16-F10 cell-derived lung metastasis mouse model. Furthermore, our results suggest that the formulation has a high impact on the in vivo efficacy of the drug and warrants further investigation in other cancers, particularly taxane resistant. In conclusion, the microtubule polymerization inhibitor CH-2-102 conjugated pH-responsive NPs induce tumor regression in lung metastasis melanoma mice, suggesting it may be an effective strategy for treating metastatic melanoma.

Recent advances in drug delivery and targeting to the brain

Our body keeps separating the toxic chemicals in the blood from the brain. A significant number of drugs do not enter the central nervous system (CNS) due to the blood-brain barrier (BBB). Certain diseases, such as tumor growth and stroke, are known to increase the permeability of the BBB. However, the heterogeneity of this permeation makes it difficult and unpredictable to transport drugs to the brain. In recent years, research has been directed toward increasing drug penetration inside the brain, and nanomedicine has emerged as a promising approach. Active targeting requires one or more specific ligands on the surface of nanoparticles (NPs), which brain endothelial cells (ECs) recognize, allowing controlled drug delivery compared to conventional targeting strategies. This review highlights the mechanistic insights about different cell types contributing to the development and maintenance of the BBB and summarizes the recent advancement in brain-specific NPs for different pathological conditions. Furthermore, fundamental properties of brain-targeted NPs will be discussed, and the standard lesion features classified by neurological pathology are summarized.

Nanoparticle Delivery of Novel PDE4B Inhibitor for the Treatment of Alcoholic Liver Disease

The incidence of alcoholic liver disease (ALD) is increasing worldwide while no effective treatment has been approved. The progression of ALD has proven to be related to the upregulation of phosphodiesterase 4 (PDE4) expression, and PDE4 inhibitors showed potential to improve ALD. However, the application of PDE4 inhibitors is limited by the gastrointestinal side effects due to PDE4D inhibition. Therefore, we used a novel PDE4B inhibitor KVA-D88 as the therapeutic for ALD treatment. KVA-D88 inhibited inflammatory response, promoted β-oxidation, increased the level of antioxidants in the hepatocytes, and suppressed hepatic stellate cell (HSC) activation in vitro. To improve the solubility and availability in vivo, KVA-D88 was encapsulated into mPEG-b-P(CB-co-LA) nanoparticles (NPs) by solvent evaporation, with a mean particle size of 135 nm and drug loading of 4.2%. We fed the male C57BL/6 mice with a Lieber–DeCarli liquid diet containing 5% (v/v) ethanol for 6 weeks to induce ALD. Systemic administration of KVA-D88 free drug and KVA-D88-loaded NPs at 5 mg/kg significantly improved the ALD in mice. KVA-D88 significantly ameliorated alcohol-induced hepatic injury and inflammation. KVA-D88 also markedly reduced steatosis by promoting fatty acid β-oxidation. Liver fibrosis and reactive oxygen species (ROS)-caused cellular damage was observed to be alleviated by KVA-D88. KVA-D88-loaded NPs proved better efficacy than free drug in the animal study. In conclusion, the novel PDE4B inhibitor KVA-D88-loaded NPs have the potential to treat ALD in mice

Effect of magnesium stearate surface coating method on the aerosol performance and permeability of micronized fluticasone propionate

In this study, we evaluated the aerodynamic performance, dissolution, and permeation behavior of micronized fluticasone propionate (FP) and magnesium stearate (MgSt) binary mixtures. Micronized FP was dry mixed with 2% w/w MgSt using a tumble mixer and a resonant acoustic mixer (RAM) with and without heating. The mixing efficacy was determined by X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) analysis. Additional techniques were used to determine powder properties such as the dynamic vapor sorption (DVS), particle size distribution (PSD) by laser diffraction light scattering, and particle surface properties by scanning electron microscope (SEM). The aerodynamic performance was studied by the next-generation impactor (NGI) using drug-loaded capsules in a PlastiApi® device. Physiochemical properties such as porosity, particle size distribution, and surface area of the formulations were studied with adsorption and desorption curves fitted to several well-known models including Brunauer-Emmett-Teller (BET), Barret Joyner Halenda (BJH), and the density functional theory (DFT). The dissolution behavior of the formulations collected on the transwell inserts incorporated into stages 3, 5, and 7 of the NGI with a membrane providing an air interface was evaluated. Drug permeability of formulations was assessed by directly depositing particles on Calu-3 cells at the air-liquid interface (ALI). Drug concentration was determined by LC-MS/MS. A better MgSt mixing on micronized FP particles was achieved by mixing with a RAM with and without heating than with a tumble mixer. A significant concomitant increase in the % of emitted dose and powder aerosol performance was observed after MgSt mixing. Formulation 4 (RAM mixing at room temperature) showed the highest rate of permeability and correlation with dissolution profile. The results show that the surface enrichment of hydrophobic MgSt improved aerosolization properties and the dissolution and permeability rate of micronized FP by reducing powder agglomerations. A simple low-shear acoustic dry powder mixing method was found to be efficient and substantially improved the powder aerosolization properties and enhanced dissolution and permeability rate.

Polymeric nanomedicine for overcoming resistance mechanisms in hedgehog and Myc-amplified medulloblastoma

Chemoresistance and inadequate therapeutics transport across the blood brain barrier (BBB) remain the major barriers to treating medulloblastoma (MB). Hedgehog (Hh) and IGF/PI3K pathways regulate tumor cell proliferation and resistance in MB. Current Hh inhibitors are effective initially to treat SHH-MB but acquire resistance. Herein, we showed that Hh inhibitor MDB5 and BRD4/PI3K dual inhibitor SF2523 synergistically inhibited the proliferation of DAOY and HD-MB03 cells when used in combination. Treatment of these MB cells with the combination of MDB5 and SF2523 significantly decreased colony formation and expression of MYCN, p-AKT, and cyclin D1 but significantly increased in Bax expression, compared to individual drugs. We used our previously reported copolymer mPEG-b-PCC-g-DC copolymer, which showed 8.7 ± 1.0 and 6.5 ± 0.1% loading for MDB5 and SF2523 when formulated into nanoparticles (NPs). There was sustained drug release from NPs, wherein 100% of MDB5 was released in 50 h, but only 60% of SF2523 was released in 80 h. Targeted NPs prepared by mixing 30:70 ratio of COG-133-PEG-b-PBC and mPEG-b-PCC-g-DC copolymer delivered a significantly higher drug concentration in the cerebellum at 6 and 24h after intravenous injection into orthotopic SHH-MB tumor-bearing NSG mice. Moreover, systemic administration of COG-133-NPs loaded with MDB5 and SF2523 resulted in decreased tumor burden compared to non-targeted drug-loaded NPs, without any hepatic toxicity. In conclusion, our nanomedicine of MDB5 and SF2523 offers a novel therapeutic strategy to treat chemoresistant MB.

Therapeutic targets, novel drugs, and delivery systems for diabetes associated NAFLD and liver fibrosis

Type 2 diabetes mellitus (T2DM) associated non-alcoholic fatty liver disease (NAFLD) is the fourth-leading cause of death. Hyperglycemia induces various complications, including nephropathy, cirrhosis and eventually hepatocellular carcinoma (HCC). There are several etiological factors leading to liver disease development, which involve insulin resistance and oxidative stress. Free fatty acid (FFA) accumulation in the liver exerts oxidative and endoplasmic reticulum (ER) stresses. Hepatocyte injury induces release of inflammatory cytokines from Kupffer cells (KCs), which are responsible for activating hepatic stellate cells (HSCs). In this review, we will discuss various molecular targets for treating chronic liver diseases, including homeostasis of FFA, lipid metabolism, and decrease in hepatocyte apoptosis, role of growth factors, and regulation of epithelial-to-mesenchymal transition (EMT) and HSC activation. This review will also critically assess different strategies to enhance drug delivery to different cell types. Targeting nanocarriers to specific liver cell types have the potential to increase efficacy and suppress off-target effects.

2,2-Bis(hydroxymethyl) propionic acid based cyclic carbonate monomers and their (co)polymers as advanced materials for biomedical applications

Designing grafted biodegradable polymers with tailored multi-functional properties is one of the most researched fields with extensive biomedical applications. Among many biodegradable polymers, polycarbonates have gained much attention due to their ease of synthesis, high drug loading, and excellent biocompatibility profiles. Among various monomers, 2,2-bis(hydroxymethyl) propionic acid (bis-MPA) derived cyclic carbonate monomers have been extensively explored in terms of their synthesis as well as their polymerization. Since the late 90s, significant advancements have been made in the design of bis-MPA derived cyclic carbonate monomers as well as in their reaction schemes. Currently, bis-MPA derived polycarbonates have taken a form of an entire platform with a multitude of applications, the latest being in the field of nanotechnology, targeted drug, and nucleic acid delivery. The present review outlines an up to date developments that have taken place in the last two decades in the design, synthesis, and biomedical applications of bis-MPA derived cyclic carbonates and their (co)polymers.

Lipid based nanocarriers for effective drug delivery and treatment of diabetes associated liver fibrosis

Non-alcoholic fatty liver disease (NAFLD) is a cluster of several liver diseases like hepatic steatosis, non-alcoholic steatohepatitis (NASH), non-alcoholic fatty liver (NAFL), liver fibrosis, and cirrhosis which may eventually progress to liver carcinoma. One of the primary key factors associated with the development and pathogenesis of NAFLD is diabetes mellitus. The present review emphasizes on diabetes-associated development of liver fibrosis and its treatment using different lipid nanoparticles such as stable nucleic acid lipid nanoparticles, liposomes, solid lipid nanoparticles, nanostructured lipid carriers, self-nanoemulsifying drug delivery systems, and conjugates including phospholipid, fatty acid and steroid-based. We have comprehensively described the various pathological and molecular events linking effects of elevated free fatty acid levels, insulin resistance, and diabetes with the pathogenesis of liver fibrosis. Various passive and active targeting strategies explored for targeting hepatic stellate cells, a key target in liver fibrosis, have also been discussed in detail in this review.

Effect of geriatric assessment (GA) and genetic profiling on overall survival (OS) of older adults with acute myeloid leukemia (AML)

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Background: GA can predict the risk of toxicities of chemotherapy in older adults. Genetic risk categories correlate with OS in AML. We previously reported a reduction in early mortality in a pre-planned interim analysis of a phase II trial with the use of GA and genetic profiling to personalize therapy selection (NCT03226418) (Blood 2019; 134(s1):120). Here, we present the results of a propensity score matched analysis demonstrating an improvement in OS over a historical control. Methods: Patients ≥60 years with a new diagnosis of AML underwent GA. Patients were considered fit for intensive chemotherapy if they had robust physical function [normal activities of daily living (ADL) and instrumental ADL, and short physical performance battery score of ≥10 out of 12], normal cognitive function (Montreal Cognitive Assessment score of ≥26 out of 30), and hematopoietic cell transplantation comorbidity index (HCT CI) of 0-2 (except for treatment related AML, where a score of 0-2 in addition to the prior history of malignancy was acceptable). Genetic profiling for therapy selection relied on karyotyping and followed the 2017 ELN criteria. Fit patients with good or intermediate-risk AML received intensive chemotherapy. Patients with high-risk AML received low-intensity chemotherapy, or CPX 351 if they were fit and met the FDA-approved indications. Pragmatic aspects of the trial included broad eligibility criteria (e.g. patients on treatment for other malignancy were enrolled) and co-management of patients with community oncologists. Mortality was compared with a historical control treated during the years 2004-2016 (after approval of HMA) and matched on gender, age, Karnofsky Performance Status (KPS), HCT CI and ELN risk category. Results: Treatment group (n = 27) vs. historical controls (n = 32) were matched in terms of age (median age, 70 vs. 68.5 years), ELN risk category (adverse risk 59% vs. 53%), HCT CI (median score of 2), KPS (median 80 vs. 85), and gender (male 44% vs. 50%). In the treatment group, 3 patients received intensive chemotherapy: CPX 351 (n = 2) or 7+3+ gemtuzumab (n = 1). Other patients received HMA alone (n = 16), decitabine and midostaurin (n = 3), or azacitidine and venetoclax after the approval of venetoclax (n = 5). Treatment in the historical control included intensive chemotherapy (n = 20) such as 7+3, or mostly HMA based low intensity chemotherapy (n = 12). OS was significantly higher in the treatment group over historical control with 1-year OS of 66% (95% CI 60-87%) vs. 16% (95% CI 7-35%). Conclusions: Our model to personalize AML therapy selection represents an innovative approach to precision medicine that incorporates both GA for patient profiling and genetic profiling of leukemia cells. Our results appear promising with superior OS (an absolute difference of 50% in 1-year OS) compared to a matched historical control. Clinical trial information: NCT03226418.

Activation of dsRNA-Dependent Protein Kinase R by miR-378 Sustains Metabolic Inflammation in Hepatic Insulin Resistance

MicroRNAs (miRNAs) are noncoding small RNAs that regulate various pathophysiological cellular processes. Here, we report that expression of the miR-378 family was significantly induced by metabolic inflammatory inducers, a high-fructose diet, and inflammatory cytokine tumor necrosis factor-α. Hepatic miRNA profiling revealed that expression of miR-378a was highly upregulated, which, in turn, targeted the 3'-untranslated region of PPARα mRNA, impaired mitochondrial fatty acid β-oxidation, and induced mitochondrial and endoplasmic reticulum stress. More importantly, the upregulated miR-378a can directly bind to and activate the double-strand RNA (dsRNA)-dependent protein kinase R (PKR) to sustain the metabolic stress. In vivo, genetic depletion of miR-378a prevented PKR activation and ameliorated inflammatory stress and insulin resistance. Counterbalancing the upregulated miR-378a using nanoparticles encapsulated with an anti-miR-378a oligonucleotide restored PPARα activity, inhibited PKR activation and ER stress, and improved insulin sensitivity in fructose-fed mice. Our study delineated a novel mechanism of miR-378a in the pathogenesis of metabolic inflammation and insulin resistance through targeting metabolic signaling at both mRNA (e.g., PPARα) and protein (e.g., PKR) molecules. This novel finding of functional interaction between miRNAs (e.g., miR-378a) and cellular RNA binding proteins (e.g., PKR) is biologically significant because it greatly broadens the potential targets of miRNAs in cellular pathophysiological processes.

Nanoformulation design and therapeutic potential of a novel tubulin inhibitor in pancreatic cancer

Successful treatment of pancreatic cancer remains a challenge due to desmoplasia, development of chemoresistance, and systemic toxicity. Herein, we synthesized (6-(3-hydroxy-4-methoxylphenyl)pyridin-2-yl) (3,4,5-trimethoxyphenyl)methanone (CH-3-8), a novel microtubule polymerization inhibitor with little susceptible to transporter-mediated chemoresistance. CH-3-8 binding to the colchicine-binding site in tubulin protein was confirmed by tubulin polymerization assay and molecular modeling. CH-3-8 disrupted microtubule dynamics at the nanomolar concentration in MIA PaCa-2 and PANC-1 pancreatic cancer cell lines. CH-3-8 significantly inhibited the proliferation of these cells, induced G2/M cell cycle arrest, and led to apoptosis. CH-3-8 is hydrophobic with an aqueous solubility of 0.97 ± 0.16 μg/mL at pH 7.4. We further conjugated it with dodecanol through diglycolate linker to increase hydrophobicity and thus loading in lipid-based delivery systems. Hence, we encapsulated CH-3-8 lipid conjugate (LDC) into methoxy poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate-graft-dodecanol) (mPEG-b-PCC-g-DC) polymeric nanoparticles (NPs) by solvent evaporation, resulting in a mean particle size of 125.6 ± 2.3 nm and drug loading of 10 ± 1.0% (w/w) while the same polymer could only load 1.6 ± 0.4 (w/w) CH-3-8 using the same method. Systemic administration of 6 doses of CH-3-8 and LDC loaded NPs at the dose of 20 mg/kg into orthotopic pancreatic tumor-bearing NSG mice every alternate day resulted in significant tumor regression. Systemic toxicity was negligible, as evidenced by histological evaluations. In conclusion, CH-3-8 LDC loaded NPs have the potential to improve outcomes of pancreatic cancer by overcoming transporter-mediated chemoresistance and reducing systemic toxicity.

Activation of dsRNA-Dependent Protein Kinase R by MicroRNA-378 Sustains Metabolic Inflammation in Hepatic Insulin Resistance

MicroRNAs (miRNAs) are noncoding small RNAs that regulate various pathophysiological cellular processes. Here we reported that expression of the miR-378 family was significantly induced by metabolic inflammatory inducers, a high-fructose diet, and inflammatory cytokine TNFα. Hepatic miRNA profiling revealed that expression of miR-378a was highly upregulated which, in turn, targeted the 3'-UTR of PPARα mRNA, impaired mitochondrial fatty acid β-oxidation and induced mitochondrial and ER stress. More importantly, the upregulated miR-378a can directly bind to and activate the dsRNA-dependent protein kinase R (PKR) to sustain the metabolic stress. In vivo, genetic depletion of miR-378a prevented PKR activation, ameliorated inflammatory stress and insulin resistance. Counterbalancing the upregulated miR-378a using nanoparticles encapsulated with an anti-miR-378a oligonucleotide restored PPARα activity, inhibited PKR activation and ER stress, and improved insulin sensitivity in the fructose-fed mice. Conclusion: Our study delineated a novel mechanism of miRNA-378a in the pathogenesis of metabolic inflammation and insulin resistance through targeting metabolic signaling at both mRNA (e.g., PPARα) and protein (e.g., PKR) molecules. This novel finding of functional interaction between miRNAs (e.g., miR-378a) and cellular RNA binding protein(s) (e.g., PKR) is biologically significant as it greatly broadens the potential targets of miRNAs in cellular pathophysiological processes.

Redox-responsive nanoplatform for codelivery of miR-519c and gemcitabine for pancreatic cancer therapy

Desmoplastic and hypoxic pancreatic cancer microenvironment induces aberrant expression of miRNAs and hypoxia-inducible factor-1α (HIF-1α) responsible for gemcitabine (GEM) resistance. We demonstrated that miR-519c was down-regulated in pancreatic cancer and transfection of miR-519c in GEM-resistant pancreatic cancer cells inhibited HIF-1α level under hypoxia. We synthesized redox-sensitive mPEG-co-P(Asp)-g-DC-g-S-S-GEM polymer, with GEM payload of 14% (w/w) and 90% GEM release upon incubation with l-glutathione. We synthesized mPEG-co-P(Asp)-g-TEPA-g-DC for complex formation with miRNA. Chemical modification of miR-519c with 2'-O-methyl phosphorothioate (OMe-PS) at 3' end enhanced its stability and activity without being immunogenic. Epidermal growth factor receptor targeting peptide GE11 decoration increased tumor accumulation of micelles after systemic administration and significantly inhibited orthotopic desmoplastic pancreatic cancer growth in NSG mice by down-regulating HIF-1α and genes responsible for glucose uptake and cancer cell metabolism. Our multifunctional nanomedicine of GEM and OMe-PS-miR-519c offers a novel therapeutic strategy to treat desmoplasia and hypoxia-induced chemoresistance in pancreatic cancer.

Functional similarity of modified cascade impactor to deposit drug particles on cells

Pulmonary drug delivery is a non-invasive and effective route for local or systemic drug administration. Despite several products in the market, the mechanism of drug absorption from the lungs is not well understood. An in vitro model for aerosol deposition and transport across epithelia that uses particle deposition may be a good predictor of and help understand in vivo drug disposition. The objective of this study was to examine the uptake of HFA fluticasone (Flovent HFA) particles at various stages of the Next Generation Impactor (NGI) by human Calu-3 cell line derived from human bronchial respiratory epithelial cell monolayer. Particles were directly deposited on Calu-3 cells incorporated onto stages 3, 5, and 7 of the NGI at the air-liquid interface (ALI). We modified the NGI apparatus to allow particle deposition directly on cells and determined the in vitro deposition characteristics using modified NGI. Particles of different size ranges showed different in vitro epithelial transport rates. This study highlights the need to develop in vitro test systems to determine the deposition of aerosol particles on cell monolayers by simultaneously considering aerodynamic properties.

The use of micelles to deliver potential hedgehog pathway inhibitor for the treatment of liver fibrosis

Rationale: Hedgehog (Hh) pathway plays an essential role in liver fibrosis by promoting the proliferation of hepatic stellate cells (HSCs) by enhancing their metabolism via yes-associated protein 1 (YAP1). Despite the presence of several inhibitors, Hh signaling cannot be controlled exclusively due to their poor efficacy and the lack of a suitable delivery system to the injury site. Therefore, it is rationale to develop new potent Hh inhibitors and suitable delivery carriers.

Methods: Based on the structure and activity of Hh inhibitor GDC-0449, we replaced its sulfonamide group with two methylpyridine-2yl at amide nitrogen to synthesize MDB5. We compared the Hh pathway inhibition and anti-fibrotic effect of MDB5 with GDC-0449 in vitro. Next, we developed MDB5 loaded micelles using our methoxy poly(ethylene glycol)-blockpoly(2-methyl-2-carboxyl-propylene carbonate-graft-dodecanol (PEG-PCC-g-DC) copolymer and characterized for physicochemical properties. We evaluated the therapeutic efficacy of MDB5 loaded micelles in common bile duct ligation (CBDL) induced liver fibrosis, mouse model. We also determined the intrahepatic distribution of fluorescently labeled micelles after MDB5 treatment.

Results: Our results show that MDB5 was more potent in inhibiting Hh pathway components and HSC proliferation in vitro. We successfully developed MDB5 loaded micelles with particle size of 40 ± 10 nm and drug loading up to 10% w/w. MDB5 loaded micelles at the dose of 10 mg/kg were well tolerated by mice, without visible sign of toxicity. The serum enzyme activities elevated by CBDL was significantly decreased by MDB5 loaded micelles compared to GDC-0449 loaded micelles. MDB5 loaded micelles further decreased collagen deposition, HSC activation, and Hh activity and its target genes in the liver. MDB5 loaded micelles also prevented liver sinusoidal endothelial capillarization (LSEC) and therefore restored perfusion between blood and liver cells.

Conclusions: Our study provides evidence that MDB5 was more potent in inhibiting Hh pathway in HSC-T6 cells and showed better hepatoprotection in CBDL mice compared to GDC-0449.

Polymeric Micellar Delivery of Novel Microtubule Destabilizer and Hedgehog Signaling Inhibitor for Treating Chemoresistant Prostate Cancer

Castration-resistant prostate cancer that has become resistant to docetaxel (DTX) represents one of the greatest clinical challenges in the management of this malignancy. There is an urgent need to develop novel therapeutic agents to overcome chemoresistance and improve the overall survival of patients. We have designed a novel microtubule destabilizer (2-(4-hydroxy-1H-indol-3-yl)-1H-imidazol-4-yl)(3,4,5-trimethoxyphenyl)methanone (QW-296) and combined it with a newly synthesized hedgehog (Hh) signaling pathway inhibitor 2-chloro-N 1-[4-chloro-3-(2-pyridinyl)phenyl]-N 4,N 4- bis(2-pyridinylmethyl)-1,4-benzenedicarboxamide (MDB5) to treat taxane-resistant (TXR) prostate cancer. The combination of QW-296 and MDB5 exhibited stronger anticancer activity toward DU145-TXR and PC3-TXR cells and suppressed tumor colony formation when compared with single-drug treatment. Because these drugs are hydrophobic, we synthesized the mPEG-p(TMC-MBC) [methoxy-poly(ethylene glycol)-block-poly(trimethylene carbonate-co-2-methyl-2-benzoxycarbonyl-propylene carbonate)] copolymer, which could self-assemble into micelles with loading capacities of 8.13% ± 0.75% and 9.12% ± 0.69% for QW-296 and MDB5, respectively. Further, these micelles provided controlled the respective drug release of 58% and 42% release of QW-296 and MDB5 within 24 hours when dialyzed against PBS (pH 7.4). We established an orthotopic prostate tumor in nude mice using stably luciferase expressing PC3-TXR cells. There was maximum tumor growth inhibition in the group treated with the combination therapy of QW-296 and MDB5 in micelles compared with their monotherapies or combination therapy formulated in cosolvent. The overall findings suggest that combination therapy with QW-296 and MDB5 has great clinical potential to treat TXR prostate cancer, and copolymer mPEG-p(TMC-MBC) could serve as an effective delivery vehicle to boost therapeutic efficacy in vivo.

Nanoparticulate delivery of potent microtubule inhibitor for metastatic melanoma treatment

Melanoma is the most aggressive type of skin cancer, which readily metastasizes through lymph nodes to the lungs, liver, and brain. Since the repeated administration of most chemotherapeutic drugs develops chemoresistance and severe systemic toxicities, herein we synthesized 2-(4-hydroxy-1H-indol-3-yl)-1H-imidazol-4-yl)(3,4,5-trimethoxyphenyl) methanone (abbreviated as QW-296), a novel tubulin destabilizing agent with little susceptible to transporter-mediated drug resistance. QW-296 disturbed the microtubule dynamics at the nanomolar concentration in A375 and B16F10 melanoma cells. QW-296 binding to colchicine-binding site on tubulin protein was confirmed by molecular modeling and tubulin polymerization assay. QW-296 significantly inhibited A375 and B16F10 cell proliferation, induced G2/M cell cycle arrest and led to apoptosis and cell death. To improve its aqueous solubility, QW-296 was encapsulated into methoxy poly(ethyleneglycol)-b-poly(carbonate-co-lactide) [mPEG-b-P(CB-co-LA)] polymeric nanoparticles by solvent evaporation, with the mean particle size of 122.0 ± 2.28 nm and drug loading of 3.70% (w/w). Systemic administration of QW-296 loaded nanoparticles into C57/BL6 albino mice bearing lung metastatic melanoma at the dose of 20 mg/kg 4 times a week for 1.5 weeks resulted in significant tumor regression and prolonged mouse median survival without significant change in mouse body weight. In conclusion, QW-296 loaded nanoparticles have the potential to treat metastatic melanoma.

ROS-Responsive Polymeric Micelles for Triggered Simultaneous Delivery of PLK1 Inhibitor/miR-34a and Effective Synergistic Therapy in Pancreatic Cancer

Ineffective drug delivery and poor prognosis are two major challenges in the treatment of pancreatic ductal adenocarcinoma (PDAC). While there is significant downregulation of tumor suppressor microRNA-34a (miR-34a), which targets many oncogenes related to proliferation, apoptosis, and invasion, high expression level of Polo-like kinase 1 (PLK1) is closely associated with short survival rates of pancreatic cancer patients. Therefore, the objective is to codeliver miR-34a mimic and small molecule PLK1 inhibitor volasertib (BI6727) using poly(ethylene glycol)-poly[aspartamidoethyl( p-boronobenzyl)diethylammonium bromide] (PEG-B-PAEBEA). This polymer could self-assemble into micelles of ∼100 nm with 10% drug loading of volasertib and form a complex with miR-34a at the N/P ratio of 18 and higher. Combination treatment of volasertib and miR-34a displayed the synergistic effect and superior antiproliferative activity along with an enhanced G2/M phase arrest and suppression of colony formation, leading to cell death due to potential c-myc targeting therapeutics. Orthotopic pancreatic tumor bearing NSG mice were scanned for fluorescence by IVIS after systemic administration of micelles encapsulating volasertib and miR-34a at doses of 5 and 1 mg/kg, respectively. Cy5.5 concentration in plasma and major organs was determined by measuring fluorescence intensity. There was significant reduction in tumor volume, and histological examination of major organs suggested negligible systemic toxicity. In conclusion, PEG-B-PAEBEA micelles carrying volasertib and miR-34a mimic have the potential to treat pancreatic cancer.

Design of Hedgehog pathway inhibitors for cancer treatment

Hedgehog (Hh) signaling is involved in the initiation and progression of various cancers and is essential for embryonic and postnatal development. This pathway remains in the quiescent state in adult tissues but gets activated upon inflammation and injuries. Inhibition of Hh signaling pathway using natural and synthetic compounds has provided an attractive approach for treating cancer and inflammatory diseases. While the majority of Hh pathway inhibitors target the transmembrane protein Smoothened (SMO), some small molecules that target the signaling cascade downstream of SMO are of particular interest. Substantial efforts are being made to develop new molecules targeting various components of the Hh signaling pathway. Here, we have discussed the discovery of small molecules as Hh inhibitors from the diverse chemical background. Also, some of the recently identified natural products have been included as a separate section. Extensive structure-activity relationship (SAR) of each chemical class is the focus of this review. Also, clinically advanced molecules are discussed from the last 5 to 7 years. Nanomedicine-based delivery approaches for Hh pathway inhibitors are also discussed concisely.

Dual responsive micelles capable of modulating miRNA-34a to combat taxane resistance in prostate cancer

There is a direct correlation between increase in the number of cancer stem cells CSCs and chemoresistance that impedes successful chemotherapy. Synergistic therapy by targeting both bulk tumor cells and CSCs has shown promise in reversing chemoresistance and treating resistant prostate cancer. Herein, we demonstrated the fabrication of a pH and glutathione (GSH) sensitive nanocarrier for co-delivery of docetaxel (DTX) and rubone (RUB), a miR-34 activator for targeting CSCs, for the treatment of taxane resistant (TXR) prostate cancer. DTX loaded P-RUB (DTX/P-RUB) micelles were prepared by encapsulating DTX into pH responsive diisopropylaminoethanol (DIPAE) and GSH responsive RUB prodrug conjugated polycarbonate based micelles. The self-assembled DTX/P-RUB micelles displayed good stability in vitro and could efficiently target to tumors by enhanced permeability and retention (EPR) effect. After endocytosis by tumor cells, the micelles underwent expansion and disassembly due to the protonation of DIPAE and GSH induced cleavage of disulfide bond in acidic endocytic vesicles, resulting in fast release of DTX and RUB. The released RUB then upregulated the intracellular miR-34a, which then affected the expression of proteins involved in chemoresistance, thus sensitizing the tumor cells towards DTX and further leading to significant inhibition of TXR tumor progression. Thus, DTX/P-RUB micelles have the potential to treat TXR prostate cancer. By taking advantage of this dual responsive strategy, the successful delivery of many other hydrophobic drugs can be achieved for cancer treatment.

Roles of microRNAs in T cell immunity: Implications for strategy development against infectious diseases

T cell immunity plays a vital role in pathogen infections. MicroRNA (miRNAs) are small, single-stranded noncoding RNAs that regulate T cell immunity by targeting key transcriptional factors, signaling proteins, and cytokines associated with T cell activation, differentiation, and function. The dysregulation of miRNA expression in T cells may lead to specific immune responses and can provide new therapeutic opportunities against various infectious diseases. Here, we summarize recent studies that focus on the roles of miRNAs in T cell immunity and highlight miRNA functions in prevalent infectious diseases. Additionally, we also provide insights into the functions of extracellular vesicle miRNAs and attempt to delineate the mechanism of miRNA sorting into extracellular vesicles and their immunomodulatory functions. Moreover, methodologies and strategies for miRNA delivery against infectious diseases are summarized. Finally, potential strategies for miRNA-based therapies are proposed.

Pharmacokinetics and biodistribution of polymeric micelles containing miRNA and small-molecule drug in orthotopic pancreatic tumor-bearing mice

Rationale: Successful treatment of pancreatic cancer remains a challenge due to desmoplasia and prevalence of KRAS mutation. While hedgehog (Hh) ligand levels are upregulated in pancreatic cancer cells and contribute to desmoplasia, there is significant downregulation of tumor suppressor let-7b, which targets mutant KRAS, C-MYC and several other genes involved in pancreatic cancer progression, invasion, and metastasis. We recently explored combination therapy of GDC-0449 (Hh inhibitor) and let-7b mimic using poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate-graft-dodecanol-graft-tetraethylenepentamine) (PEG-b-PCC-g-DC-g-TEPA) micelles in pancreatic tumor mouse model. Here, our objective was to determine the biodistribution (BD), pharmacokinetics (PK), therapeutic efficacy and toxicity of this micellar formulation. Methods: We determined the PK of micelles encapsulating Cy5.5-let-7b and GDC-0449 following intravenous injection in orthotopic pancreatic tumor-bearing NSG mice at doses of 2 mg/kg and 10 mg/kg, respectively. Mice were scanned for fluorescence by IVIS to determine the biodistribution of Cy5.5-let-7b at the whole-body level, and its concentration in plasma and major organs was determined by measuring fluorescence using a fluorimeter and by real-time RT-PCR. GDC-0449 concentration was determined by LC/MS/MS. Therapeutic efficacy and toxicity of the micellar formulation of let-7b and GDC-0449 was also determined after two weeks of treatment. Results: The use of a micellar formulation markedly prolonged the elimination half-life (t_{1/2, e}) of Cy5.5-let-7b in plasma from 0.49 ± 0.19 h to 2.65 ± 0.46 h and increased the area-under-the-curve (AUC _0-∞ ) by 7-fold, while t_1/2,e and AUC _0-∞ of GDC-0449 were increased by 1.78-fold and 3.2-fold, respectively. The micelles significantly decreased the clearance of both encapsulated let-7b mimic and GDC-0449 compared to the emulsion formulation. Compared to the emulsion counterpart, the micellar formulation elevated the delivery of Cy5.5-let-7b and GDC-0449 to the orthotopic pancreatic tumor tissue by 7.8- and 4.2-fold, respectively. Furthermore, there was a significant reduction in tumor volume and negligible systemic toxicity as evident by hematological parameters and histological evaluation. Conclusion: PEG-b-PCC-g-DC-g-TEPA micelles carrying GDC-0449 and let-7b mimic have great potential to improve drug delivery for pancreatic cancer treatment.

Cholesterol and Morpholine Grafted Cationic Amphiphilic Copolymers for miRNA-34a Delivery

miR-34a is a master tumor suppressor playing a key role in the several signaling mechanisms involved in cancer. However, its delivery to the cancer cells is the bottleneck in its clinical translation. Herein we report cationic amphiphilic copolymers grafted with cholesterol (chol), N, N-dimethyldipropylenetriamine (cation chain) and 4-(2-aminoethyl)morpholine (morph) for miR-34a delivery. The copolymer interacts with miR-34a at low N/P ratios (∼2/1) to form nanoplexes of size ∼108 nm and a zeta potential ∼ +39 mV. In vitro studies in 4T1 and MCF-7 cells indicated efficient transfection efficiency. The intracellular colocalization suggested that the copolymer effectively transported the FAM labeled siRNA into the cytoplasm within 2 h and escaped from the endo-/lysosomal environment. The developed miR-34a nanoplexes inhibited the breast cancer cell growth as confirmed by MTT assay wherein 28% and 34% cancer cell viability was observed in 4T1 and MCF-7 cells, respectively. Further, miR-34a nanoplexes possess immense potential to induce apoptosis in both cell lines.

MicroRNAs in the pathogenesis and treatment of progressive liver injury in NAFLD and liver fibrosis

Non-alcoholic fatty liver disease (NAFLD) increases the risk of various liver injuries, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis, and ultimately hepatocellular carcinoma (HCC). Ample evidence has suggested that aberrant expression of microRNAs (miRNAs) is functionally involved in the activation of cellular stress, inflammation and fibrogenesis in hepatic cells, including hepatocytes, Kupffer and hepatic stellate cells (HSCs), at different pathological stages of NAFLD and liver fibrosis. Here, we overview recent findings on the potential role of miRNAs in the pathogenesis of NAFLD, including lipotoxicity, oxidative stress, metabolic inflammation and fibrogenesis. We critically assess the literatures on both human subjects and animal models of NAFLD and liver fibrosis with miRNA dysregulation and their mechanisms of actions in liver damage. We further highlight the potential use of miRNA mimics or antimiRNAs as therapeutic approaches for the prevention and treatment of NAFLD and liver fibrosis.

Lipid-polymer hybrid nanocarriers for delivering cancer therapeutics

Cancer remained a major cause of death providing diversified challenges in terms of treatment including non-specific toxicity, chemoresistance and relapse. Nanotechnology- based delivery systems grabbed tremendous attention for delivering cancer therapeutics as they provide benefits including controlled drug release, improved biological half-life, reduced toxicity and targeted delivery. Majority of the nanocarriers consists of either a polymer or a lipid component along with other excipients to stabilize the colloidal system. Lipid-based systems provide advantages like better entrapment efficiency, scalability and low- cost raw materials, however, suffer from limitations including instability, a burst release of the drug, and limited surface functionalization. On the other hand, polymeric systems provide an excellent diversity of chemical modifications, stability, controlled release, however limited drug loading capacities and scale up limit their use. Hybrid nanocarriers consisting of lipid and polymer were able to overcome some of these disadvantages while retaining the advantages of both the systems. Designing a stable lipid-polymer hybrid system requires a thorough understanding of the material properties and their behavior in in vitro and in vivo environments. This review highlights the current status and future prospects of lipid-polymer hybrid systems with a particular focus on cancer nanotherapeutics.

Challenges and Recent Advances in Medulloblastoma Therapy

Medulloblastoma (MB) is the most common childhood brain tumor, which occurs in the posterior fossa. MB tumors are highly heterogeneous and have diverse genetic make-ups, with differential microRNA (miRNA) expression profiles and variable prognoses. MB can be classified into four subgroups, each with different origins, pathogenesis, and potential therapeutic targets. miRNA and small-molecule targeted therapies have emerged as a potential new therapeutic paradigm in MB treatment. However, the development of chemoresistance due to surviving cancer stem cells and dysregulation of miRNAs remains a challenge. Combination therapies using multiple drugs and miRNAs could be effective approaches. In this review we discuss various MB subtypes, barriers, and novel therapeutic options which may be less toxic than current standard treatments.

EGFR-Targeted Cationic Polymeric Mixed Micelles for Codelivery of Gemcitabine and miR-205 for Treating Advanced Pancreatic Cancer

Gemcitabine (GEM), a first-line chemotherapy for pancreatic cancer undergoes rapid metabolism and develops chemoresistance after repeated administration. We previously demonstrated that the combination of GEM and miR-205 provides an effective therapeutic strategy to sensitize GEM-resistant pancreatic cancer cells. Since epidermal growth factor receptor (EGFR) is overexpressed in pancreatic cancer cells, in this study, we aimed to deliver mixed micelles containing GEM and miR-205 decorated with EGFR-targeting cetuximab (C225) monoclonal antibody for targeted therapy. Cetuximab C225 was conjugated to malemido-poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate-graft-dodecanol (C225-PEG-PCD) to prepare mixed micelles with mPEG-b-PCC-g-GEM-g-DC-g-TEPA for targeted codelivery of GEM and miR-205. This mixed micelle formulation showed a significant enhancement in EGFR-mediated cellular uptake in GEM-resistant MIA PaCa-2^R cells. Further, an enhanced tumor accumulation of C225-micelles conjugated with near-infrared fluorescent Cy7.5 dye and Dy677-labeled miR-205 in orthotopic pancreatic tumor bearing NSG mice was evident after systemic administration. In addition, inhibition of tumor growth was also observed with increased apoptosis and reduced EMT after treatment with C225-micelles containing GEM and miR-205. Therefore, we believe that the targeted delivery of GEM and miR-205 in combination could be a novel strategy for treating advanced pancreatic cancer.

Micellar Delivery of miR-34a Modulator Rubone and Paclitaxel in Resistant Prostate Cancer

Treatment of prostate cancer with paclitaxel often fails due to the development of chemoresistance caused by downregulation of the tumor suppressor gene miR-34a. In this study, we demonstrate that codelivery of paclitaxel and 2'-hydroxy-2,4,4',5,6'-pentamethoxychalcone (termed rubone) drives upregulation of miR-34a and chemosensitizes paclitaxel-resistant prostate cancer cells, killing both cancer stem-like cells (CSC) and bulk tumor cells. Rubone upregulated miR-34a and reversed its downstream target genes in DU145-TXR and PC3-TXR cells. Paclitaxel and rubone combination therapy inhibited tumor cell growth, migration, and CSC population growth. We synthesized poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate-graft-dodecanol; PEG-PCD) to prepare micelles. The drug-loading capacities were 9.70% ± 0.10% and 5.34% ± 0.02% for paclitaxel and rubone, respectively, controlling a drug release of 60.20% ± 2.67% and 60.62% ± 4.35% release of paclitaxel and rubone at 24 hours. Delivery of miR-34a and rubone decreased PC3-TXR cell viability with increasing paclitaxel concentration. Coincubation with a miR-34a inhibitor diminished the effect of rubone. Paclitaxel IC₅₀ in PC3 and PC3-TXR cells was 55.6 and 2,580 nmol/L, respectively, but decreased to 49.8 and 93.2 nmol/L when treated in combination with rubone, demonstrating a reversal of paclitaxel resistance by rubone. Systemic administration of micelles carrying paclitaxel and rubone inhibited orthotopic prostate tumor growth in nude mice, compared with monotherapy, by reversing the expression of miR-34a, SIRT1, cyclin D1, and E-cadherin. In summary, our results showed how rubone acts as an efficient small-molecule modulator of miR-34a to reverse chemoresistance and further enhance the therapeutic efficacy of paclitaxel in paclitaxel-resistant prostate cancer. Cancer Res; 77(12); 3244-54. ©2017 AACR.

Recent advances in hepatocellular carcinoma therapy

Hepatocellular carcinoma (HCC), also called malignant hepatoma, is one of the deadliest cancers due to its complexities, reoccurrence after surgical resection, metastasis and heterogeneity. Incidence and mortality of HCC are increasing in Western countries and are expected to rise as a consequence of the obesity epidemic. Multiple factors trigger the initiation and progression of HCC including chronic alcohol consumption, viral hepatitis B and C infection, metabolic disorders and age. Although Sorafenib is the only FDA approved drug for the treatment of HCC, numerous treatment modalities such as transcatheter arterial chemoembolization/transarterial chemoembolization (TACE), radiotherapy, locoregional therapy and chemotherapy have been tested in the clinics. Polymeric nanoparticles, liposomes, and micelles carrying small molecules, proteins, peptides and nucleic acids have attracted great attention for the treatment of various cancers including HCC. Herein, we discuss the pathogenesis of HCC in relation to its various recent treatment methodologies using nanodelivery of monoclonal antibodies (mAbs), small molecules, miRNAs and peptides. Synopsis of recent clinical trials of mAbs and peptide drugs has been presented with a broad overview of the pathogenesis of the disease and treatment efficacy.

Polymer conjugate of a microtubule destabilizer inhibits lung metastatic melanoma

Melanoma is the most aggressive type of skin cancer. It is highly metastatic, migrating through lymph nodes to distant sites of the body, especially to lungs, liver and brain. Systemic chemotherapy remains the mainstay of treatment; however, the development of multidrug resistance (MDR) restricts the efficacy of current chemotherapeutic drugs. We synthesized a series of microtubule destabilizers, substituted methoxybenzoyl-ary-thiazole (SMART) compounds, which inhibited tubulin polymerization and effectively circumvented MDR. Due to poor water solubility of SMART compounds, co-solvent delivery is required for their systemic administration, which is usually associated with hepatotoxicity, nephrotoxicity and hemolysis. To solve this problem and also to increase circulation time, we synthesized a new SMART analogue, SMART-OH, and its polymer-drug conjugate, methoxy-poly (ethylene glycol)-block-poly (2-methyl-2-carboxyl-propylene carbonate-graft-SMART-graft-dodecanol) (abbreviated as P-SMART), with 14.3±2.8% drug payload of SMART-OH. Similar to its parent drug, P-SMART showed significant anticancer activity against melanoma cells in cytotoxicity, colony formation, and cell invasion studies. In addition, P-SMART treatment led to cell cycle arrest at G2/M phase and cell accumulation in sub-G1 phase. We established a model of metastatic melanoma to the lung in C57/BL6 albino mice to determine in vivo efficacy of P-SMART and SMART-OH at the dose of 20mg/kg. P-SMART treatment resulted in significant inhibition of tumor growth and prolonged mouse median survival. In conclusion, P-SMART, a novel polymer-microtubule destabilizer conjugate, has the potential to treat metastatic melanoma.

Biodistribution of Self-Assembling Polymer-Gemcitabine Conjugate after Systemic Administration into Orthotopic Pancreatic Tumor Bearing Mice

Therapeutic efficacy of gemcitabine (GEM) is severely limited due to its rapid metabolism by enzymatic deamination in vivo. We recently determined its therapeutic efficacy before (F-GEM) and after conjugation to poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate) (mPEG-b-PCC-g-GEM-g-DC, abbreviated as P-GEM) in subcutaneous and orthotopic pancreatic tumor bearing mice. In this study, pharmacokinetic (PK) parameters and biodistribution profiles of F-GEM and P-GEM were determined after intravenous injection into orthotopic pancreatic tumor bearing NSG mice. To assess the short-term toxicity, the levels of hematological, hepatic, and renal injury markers were measured after 24 h postadministration into these mice. P-GEM was distributed to all the major organs, with higher accumulation in the liver, spleen, and tumor compared to F-GEM. Area under the curve (AUC), elimination half-life (t_1/2), and mean residence time (MRT) of P-GEM treated group were significantly higher compared to those of F-GEM treated group: 246,425 ± 1605 vs 83,591 ± 1844 ng/mL × h as AUC, 5.77 ± 2.02 vs 1.99 ± 0.09 h as t_1/2, and 4.45 ± 0.15 vs 1.12 ± 0.13 h as MRT. Further, P-GEM exhibited negligible systemic toxicity as evidenced by almost similar alanine aminotransferase (ALT) and aspartate aminotransferase (AST) values for both P-GEM and F-GEM. These results suggest that P-GEM protects GEM from degradation and provides sustained drug release, resulting in enhanced GEM delivery to the tumor by more than 2.5-fold compared to F-GEM. Hence, P-GEM is a promising gemcitabine conjugated polymeric micelle for treating pancreatic cancer.

Combination therapy of paclitaxel and cyclopamine polymer-drug conjugates to treat advanced prostate cancer

Repeated treatments with chemotherapeutic agent(s) fail due to cancer stem cells (CSCs) and chemoresistance regulated by microRNAs (miRNA) whose expression alters owing to dysfunctional signaling pathways including Hedgehog (Hh) signaling. We previously demonstrated the combination of Hh inhibitor cyclopamine (CYP) and paclitaxel (PTX) effectively inhibit PTX-resistant cells and side population, a cell fraction rich in CSCs. In this study, we synthesized mPEG-b-PCC-g-PTX-g-DC (P-PTX) and mPEG-b-PCC-g-CYP-g-DC (P-CYP) polymer-drug conjugates, which they self-assembled into micelles. The combination of P-PTX and P-CYP alleviated PTX resistance and suppressed tumor colony formation. Further, combination therapy inhibited Hh signaling and up-regulated tumor suppressor miRNAs. We established orthotopic prostate tumor in nude mice and there was significant tumor growth inhibition in the group treated with the combination therapy of P-PTX and P-CYP compared with monotherapy. In conclusion, this combination therapy of P-PTX and P-CYP has the potential to treat chemoresistant prostate cancer.

Mesenchymal stem cell and derived exosome as small RNA carrier and Immunomodulator to improve islet transplantation

Human bone marrow mesenchymal stem cells (hBMSCs) and their exosomes can suppress immune reaction and deliver small RNAs. Thus, they may improve islet transplantation by delivering small RNAs for promoting islet function and inhibiting immune rejection. Here, we proposed an hBMSC and its exosome-based therapy to overcome immune rejection and poor islet function, both of which hinder the success of islet transplantation. We found overexpressed siFas and anti-miR-375 in plasmid encoding shFas and anti-miR-375 transfected hBMSC-derived exosomes, which silenced Fas and miR-375 of human islets and improved their viability and function against inflammatory cytokines. This plasmid transfected hBMSCs downregulated Fas and miR-375 of human islets in a humanized NOD scid gamma (NSG) mouse model, whose immune reaction was inhibited by injecting hBMSC and peripheral blood mononuclear cell (PBMC) co-cultured exosomes. These exosomes suppressed immune reaction by inhibiting PBMC proliferation and enhancing regulatory T cell (Treg) function. Collectively, our studies elucidated the mechanisms of RNA delivery from hBMSCs to human islets and the immunosuppressive effect of hBMSC and peripheral blood mononuclear cell co-cultured exosomes for improving islet transplantation.

Micelle Mixtures for Coadministration of Gemcitabine and GDC-0449 To Treat Pancreatic Cancer

Hedgehog (Hh) signaling plays an important role in the development and metastasis of pancreatic ductal adenocarcinoma (PDAC). Although gemcitabine (GEM) has been used as a first-line therapy for PDAC, its rapid metabolism and short plasma half-life restrict its use as a single chemotherapy. Combination therapy with more than one drug is a promising approach for treating cancer. Herein, we report the use of methoxy poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate)-graft-dodecanol (mPEG-b-PCC-g-DC) copolymer for conjugating GEM and encapsulating a Hh inhibitor, vismodegib (GDC-0449), into its hydrophobic core for treating PDAC. Our objective was to determine whether the micelle mixtures of these two drugs could show better response in inhibiting Hh signaling pathway and restraining the proliferation and metastasis of pancreatic cancer. The in vivo stability of GEM significantly increased after conjugation, which resulted in its increased antitumor efficacy. Almost 80% of encapsulated GDC-0449 and 19% conjugated GEM were released in vitro at pH 5.5 in 48 h in a sustained manner. The invasion, migration, and colony forming features of MIA PaCa-2 cells were significantly inhibited by micelle mixture carrying GEM and GDC-0449. Remarkable increase in PARP cleavage and Bax proved increased apoptosis by this combination formulation compared to individual micelles. This combination therapy efficiently inhibited tumor growth, increased apoptosis, reduced Hh ligands PTCH-1 and Gli-1, and lowered EMT-activator ZEB-1 when injected to athymic nude mice bearing subcutaneous tumor generated using MIA PaCa-2 cells compared to monotherapy as observed from immunohistochemical analysis. In conclusion, micelle mixtures carrying GEM and GDC-0449 have the potential to treat pancreatic cancer.

EGFR-Targeted Polymeric Mixed Micelles Carrying Gemcitabine for Treating Pancreatic Cancer

The objective of this study was to design GE11 peptide (YHWYGYTPQNVI) linked micelles of poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate-graft-gemcitabine-graft-dodecanol (PEG-b-PCC-g-GEM-g-DC) for enhanced stability and target specificity of gemcitabine (GEM) to EGFR-positive pancreatic cancer cells. GE11-PEG-PCD/mPEG-b-PCC-g-GEM-g-DC mixed micelles showed EGFR-dependent enhanced cellular uptake, and cytotoxicity as compared to scrambled peptide HW12-PEG-PCD/mPEG-b-PCC-g-GEM-g-DC mixed micelles and unmodified mPEG-b-PCC-g-GEM-g-DC micelles. Importantly, GE11-linked mixed micelles preferentially accumulated in orthotopic pancreatic tumor and tumor vasculature at 24 h post systemic administration. GE11-linked mixed micelles inhibited orthotopic pancreatic tumor growth compared to HW12-linked mixed micelles, unmodified mPEG-b-PCC-g-GEM-g-DC micelles, and free GEM formulations. Tumor growth inhibition was mediated by apoptosis of tumor cells and endothelial cells as determined by immunohistochemical staining. In summary, GE11-linked mixed micelles is a promising approach to treat EGFR overexpressing cancers.

Synthesis and Characterization of a Novel Mycophenolic Acid-Quinic Acid Conjugate Serving as Immunosuppressant with Decreased Toxicity

Mycophenolic acid (MPA) is one of the most commonly used immunosuppressive drugs for improving the outcome of cell and organ transplantations. However, an undesired adverse effect of MPA impedes its application in the clinics for post-transplant patients. By conjugating MPA to quinic acid (QA) via amide bonds, we synthesized a novel immunosuppressant, N-[2-[[(4E)-6-(1,3-dihydro-4-hydroxy-6-methoxy-7-methyl-3-oxo-5-isobenzofuranyl)-4-methyl-1-oxo-4-hexen-1-yl]amino]ethyl]-(1α,3R,4α,5R)-1,3,4,5-tetrakis(acetyloxy)cyclohexanecarboxamide (abbreviated as MQ4), which exhibits improved stability demonstrated by its incubation in vitro with human plasma, suggesting its better resistance to hydrolytic degradation induced by plasma enzyme. While the immunosuppressive effect of MQ4 on human lymphocyte proliferation was partially compromised as shown by flow cytometry, significant decrease in cytotoxicity of MQ4 to insulin producing β cells could compensate this drawback to some degree. There was a decreased level of apoptotic mediator caspase-3, which may contribute to the decreased toxicity of MQ4 to INS-1E cells. MQ4 could further improve insulin stimulation index and downregulate NFκB expression compared to physical mixing of QA to MPA. Taken together, MQ4 is a promising immunosuppressive agent for preventing and minimizing post-transplanted immune rejection.

Co-delivery of small molecule hedgehog inhibitor and miRNA for treating liver fibrosis

In liver fibrosis, secretion of growth factors and hedgehog (Hh) ligands by hepatic parenchyma upon repeated insults results in transdifferentiation of quiescent hepatic stellate cells (HSCs) into active myofibroblasts which secrete excessive amounts of extracellular matrix (ECM) proteins. An Hh inhibitor GDC-0449 and miR-29b1 can play an important role in treating liver fibrosis by inhibiting several pro-fibrotic genes. Our in-silico analysis indicate that miR-29b1 targets several profibrotic genes like collagen type I & IV, c-MYC, PDGF-β and PI3K/AKT which are upregulated in liver fibrosis. Common bile duct ligation (CBDL) resulted in an increase in Ptch-1, Shh and Gli-1 expression. miR-29b1 and GDC-0449 were co-formulated into micelles using methoxy poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate-graft-dodecanol-graft-tetraethylenepentamine) (mPEG-b-PCC-g-DC-g-TEPA) copolymer, and injected systemically into CBDL mice. High concentrations of GDC-0449 and miR-29b1 were delivered to liver cells as determined by in situ liver perfusion at 30 min post systemic administration of their micelle formulation. There was a significant decrease in collagen deposition in the liver and serum injury markers, leading to improvement in liver morphology. Combination therapy was more effective in providing hepatoprotection, lowering liver injury related serum enzyme levels, reducing fibrotic protein markers such as collagen, α-SMA, FN-1 and p-AKT compared to monotherapy. In conclusion, inhibition of Hh pathway and restoration of miR-29b1 have the potential to act synergistically in treating CBDL-induced liver fibrosis in mice.