An Evaluation of the Anticancer Properties of SYA014, a Homopiperazine-Oxime Analog of Haloperidol in Triple Negative Breast Cancer Cells.

Triple negative breast cancer (TNBC) is a type of breast cancer associated with early metastasis, poor prognosis, high relapse rates, and mortality. Previously, we demonstrated that SYA013, a selective σ2RL, could inhibit cell proliferation, suppress migration, reduce invasion, and induce mitochondria-mediated apoptosis in MDA-MB-231 cell lines, although we were unable to demonstrate the direct involvement of sigma receptors. This study aimed to determine the anticancer properties and mechanisms of action of SYA014, [4-(4-(4-chlorophenyl)-1,4-diazepan-1-yl)-1-(4-fluorophenyl)butan-1-one oxime], an oxime analogue of SYA013, the contribution of its sigma-2 receptor (σ2R) binding, and its possible synergistic use with cisplatin to improve anticancer properties in two TNBC cell lines, MDA-MB-231 (Caucasian) and MDA-MB-468 (Black). In the present investigation, we have shown that SYA014 displays anticancer properties against cell proliferation, survival, metastasis and apoptosis in the two TNBC cell lines. Furthermore, a mechanistic investigation was conducted to identify the apoptotic pathway by which SYA014 induces cell death in MDA-MB-231 cells. Since SYA014 has a higher binding affinity for σ2R compared to σ1R, we tested the role of σ2R on the antiproliferative property of SYA014 with a σ2R blockade. We also attempted to evaluate the combination effect of SYA014 with cisplatin in TNBC cells.

A Mechanistic Investigation on the Anticancer Properties of SYA013, a Homopiperazine Analogue of Haloperidol with Activity against Triple Negative Breast Cancer Cells.

Triple-negative breast cancer (TNBC) is one of the most malignant cancers associated with early metastasis, poor clinical prognosis, and high recurrence rate. TNBC is a distinct subtype of breast cancer that lacks estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor 2 receptors (HER2). Development of effective TNBC therapies has been limited partially due to the lack of specific molecular targets and chemotherapy involving different cytotoxic drugs suffers from significant side effects and drug-resistance development. Therefore, there is an unmet need for the development of novel and efficient therapeutic drugs with reduced side effects to treat TNBC. We have previously reported that certain analogues of haloperidol (a typical antipsychotic drug used for treating mental/mood disorders such as schizophrenia and bipolar disorder) suppress the viability of a variety of solid tumor cell lines, and we have identified 4-(4-(4-chlorophenyl)-1,4-diazepan-1-yl)-1-(4-fluoro-phenyl)butan-1-one (SYA013) with such antiproliferative properties. Interestingly, unlike haloperidol, SYA013 shows moderate selectivity toward σ2 receptors. In this study, we explored the potential of SYA013 in modulating the important biological events associated with cell survival and progression as well as the mechanistic aspects of apoptosis in a representative TNBC cell line (MDA-MB-231). Our results indicate that SYA013 inhibits the proliferation of MDA-MB-231 cells in a concentration-dependent manner and suppresses cell migration and invasion. Apoptotic studies were also conducted in MDA-MB-468 cells (cells derived from a 51-year old Black female with metastatic adenocarcinoma of the breast.). In addition, we have demonstrated that SYA013 induces MDA-MB-231 cell death through the intrinsic apoptotic pathway and may suppress tumor progression and metastasis. Taken together, our study presents a mechanistic pathway of the anticancer properties of SYA013 against TNBC cell lines and suggests a potential for exploring SYA013 as a lead agent for development against TNBC.

Protease Inhibitors for the Treatment of HIV/AIDS: Recent Advances and Future Challenges.

Acquired Immunodeficiency Syndrome (AIDS) is a chronic disease characterized by multiple life-threatening illnesses caused by a retro-virus, Human Immunodeficiency Virus (HIV). HIV infection slowly destroys the immune system and increases the risk of various other infections and diseases. Although, there is no immediate cure for HIV infection/AIDS, several drugs targeting various cruxes of HIV infection are used to slow down the progress of the disease and to boost the immune system. One of the key therapeutic strategies is Highly Active Antiretroviral Therapy (HAART) or ' AIDS cocktail' in a general sense, which is a customized combination of anti-retroviral drugs designed to combat the HIV infection. Since HAART's inception in 1995, this treatment was found to be effective in improving the life expectancy of HIV patients over two decades. Among various classes of HAART treatment regimen, Protease Inhibitors (PIs) are known to be widely used as a major component and found to be effective in treating HIV infection/AIDS. For the past several years, a variety of protease inhibitors have been reported. This review outlines the drug design strategies of PIs, chemical and pharmacological characteristics of some mechanism-based inhibitors, summarizes the recent developments in small molecule based drug discovery with HIV protease as a drug target. Further discussed are the pharmacology, PI drug resistance on HIV PR, adverse effects of HIV PIs and challenges/impediments in the successful application of HIV PIs as an important class of drugs in HAART regimen for the effective treatment of AIDS.

Exploring membrane permeability of Tomatidine to enhance lipid mediated nucleic acid transfections.

Intracellular delivery of nucleic acids is one of the critical steps in the transfections. Prior findings demonstrated various strategies including membrane fusion, endosomal escape for the efficient cytoplasmic delivery. In our continuing efforts to improve the nucleic acids transfections, we harnessed cell permeable properties of Tomatidine (T), a steroidal alkaloid abundantly found in green tomatoes for maximizing intracellular delivery of lipoplexes. We doped Tomatidine into liposomes of cationic lipid with amide linker (A) from our lipid library. Six liposomal formulations (AT) of Lipid A (1 mM) with varying concentrations of Tomatidine (0-1 mM) were prepared and evaluated for their transfection efficacies. Owing to its signature characteristic of cell membrane permeability, Tomatidine modulated endocytosis process, enhanced the intracellular delivery of the lipoplexes, and in turn increased the transfection efficacy of cationic liposomes. Our findings provide 'proof of concept' for enhancing transfections in gene delivery applications with Tomatidine in cationic liposomal formulations. These findings can be further applied in lipid mediated gene therapy and drug delivery applications.

l-Dopa and dopamine conjugated naphthalenediimides modulate amyloid ß toxicity.

The process of protein misfolding and aggregation to form neurotoxic species is strongly implicated in most of the neurodegenerative disorders. In particular, amyloid beta (Aß) misfolding and aggregation is central to pathophysiological processes of Alzheimer's disease. The development of aggregation modulators has enormous implications in the discovery of effective therapeutic agents for Alzheimer's disease. Herein, we report the design and synthesis of a series of natural amino acid, l-dopa and dopamine appended derivatives of naphthalenediimide (NDI) to identify efficient aggregation modulators. Furthermore, the molecular docking studies revealed the possible binding sites and binding mode of NDI-conjugates to Aß aggregates. Among the designed NDI-conjugates, l-dopa and dopamine derivatives (NLD and NDP, respectively) showed excellent aggregation modulation efficiency (inhibition and dissolution), as shown by the thioflavin T (ThT) binding assays, dot blot analysis and in cellulo studies. The docking results from in silico studies are in good agreement with the experimental data. In addition to their significant modulation efficiency towards Aß aggregation, NLD and NDP possess antioxidant activity conducive to the development of disease-modifying therapeutic agents for the treatment of Alzheimer's disease.

Enhanced Spacer Length between Mannose Mimicking Shikimoyl and Quinoyl Headgroups and Hydrophobic Region of Cationic Amphiphile Increases Efficiency of Dendritic Cell Based DNA Vaccination: A Structure-Activity Investigation.

In the field of dendritic cell based genetic immunization, previously we showed that liposomes of cationic amphiphiles containing mannose-mimicking shikimoyl headgroup are promising DNA vaccine carriers for dendritic cell (DC) transfection. The present structure-activity study reports on the influence of spacer length (between mannose-mimicking headgroups and quaternary nitrogen centers) in modulating the DC-transfection efficiencies. Further, we report on the anti-melanoma immune response inducing properties of the promising cationic amphiphiles in syngeneic C57BL/6J mice under prophylactic settings.

An anti-oxidant, α-lipoic acid conjugated oleoyl-sn-phosphatidylcholineas a helper lipid in cationic liposomal formulations.

Development of safe non-viral carrier systems for efficient intra-cellular delivery of drugs and genes hold promise in the area of translational research. Liposome based delivery systems have emerged as one of the attractive strategies for efficient delivery of drugs and nucleic acids. To this end, number of investigations was carried on liposomal formulations using lipids for achieving higher efficiency in transfection with lower cytotoxicities. In our efforts to develop safer and efficient liposomal delivery systems, we synthesized a novel anti-oxidant lipid, α-lipoyl, oleyl-sn-phosphatidylcholine (LOPC) and used as a helper lipid in combination with a cationic amphiphile, Di-Stearyl Dihydroxy Ethyl Ammonium Chloride (DSDEAC) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) at varying concentrations of LOPC. DNA binding properties of the liposomal formulations (DS, DS LA1, DS LA2 and DS LA3) revealed that increasing the percentage of single aliphatic chain lipid LOPC, did not affect the DNA binding properties. But, transfection profiles of these liposomal formulations in 3 different cell lines (HeLa, HEK 293 and MCF7) showed difference in their efficacies. Results showed that optimal percentage of LOPC i.e. 25% in DSDEAC and DOPC at 1:1 molar ratio (DS LA1) enhanced transfection as compared to DSDEAC:DOPC alone. The endosomal escape studies with NBD labelled lysotracker and Rhodamine labelled liposomal formulations revealed that DS LA1 and DS LA2 facilitated the release of genetic cargo with a better efficiency than their counter parts. Reactive Oxygen Species (ROS), a key modulator of necroptosis were lowered with the treatment of DS LA1 than other liposomal formulations. Here in, we present a novel liposomal formulation using DSDEAC and DOPC at 1:1 molar ratio doped with 25-50% (mole ratio) LOPC as an efficient delivery system for enhanced transfection with quenching of ROS levels compared to formulations without LOPC.

Green Transfection: Cationic Lipid Nanocarrier System Derivatized from Vegetable Fat, Palmstearin Enhances Nucleic Acid Transfections.

Cationic lipid-guided nucleic acid delivery holds great promise in gene therapy and genome-editing applications for treating genetic diseases. However, the major challenge lies in achieving therapeutically relevant efficiencies. Prior findings, including our own, demonstrated that asymmetry in the hydrophobic core of cationic lipids imparted superior transfection efficiencies. To this end, we have developed a lipid nanocarrier system with an asymmetric hydrophobic core (PS-Lips) derived from a mixture of fatty acids of food-grade palmstearin and compared its efficiency with symmetric palmitic acid-based nanocarrier system (P-Lip). PS-Lips exhibited superior transfection efficiencies with both plasmid DNA (pDNA) and mRNA in multiple cultured cells than the control P-Lip. More importantly, PS-Lips exhibited 2-fold superior transfections with linear nucleic acid, green fluorescent protein (GFP) mRNA in hematopoietic cells, when compared with the commercial control lipofectamine RNAiMAX. PS-Lips was also found to be effective in delivering genome-editing tools (CRISPR/Cas9, sgRNA encoded pDNA with a reporter GFP construct) than P-Lip in HEK-293 cells. In the present study, we report that cationic liposomes derivatized from natural food-grade fat palmstearin with a natural hydrophobic core asymmetry are efficient in delivering both linear and circular nucleic acids. In particular, PS-Lips is efficient in delivering mRNA to hematopoietic cells. These findings can be further exploited in the genome-editing approach for treating ß-globinopathies.

Synthesis and characterization of brain penetrant prodrug of neuroprotective D-264: Potential therapeutic application in the treatment of Parkinson's disease.

Parkinson's disease (PD) is one of the major debilitating neurodegenerative disorders affecting millions of people worldwide. Progressive loss of dopamine neurons resulting in development of motor dysfunction and other related non-motor symptoms is the hallmark of PD. Previously, we have reported on the neuroprotective property of a potent D3 preferring agonist D-264. In our goal to increase the bioavailability of D-264 in the brain, we have synthesized a modified cysteine based prodrug of D-264 and evaluated its potential in crossing the blood-brain barrier. Herein, we report the synthesis of a novel modified cysteine conjugated prodrug of potent neuroprotective D3 preferring agonist D-264 and systematic evaluation of the hydrolysis pattern of the prodrug to yield D-264 at different time intervals in rat plasma and brain homogenates using HPLC analysis. Furthermore, we have also performed in vivo experiments with the prodrug to evaluate its enhanced brain penetration ability.

Assessment of Protective Role of Multifunctional Dopamine Agonist D-512 Against Oxidative Stress Produced by Depletion of Glutathione in PC12 Cells: Implication in Neuroprotective Therapy for Parkinson's Disease.

Oxidative stress has been strongly implicated in the progression of Parkinson's disease (PD). Depletion of cytoplasmic glutathione levels is one of the indications of oxidative stress, which occur in the substantia nigra of PD patients at an early stage of the disease process. It has been shown that glutathione depletion causes the inhibition of mitochondrial complex I, thus affecting mitochondrial function leading to oxidative stress via production of reactive oxygen species. Studies were carried out to investigate the role of D-512, a potent multifunctional neuroprotective D2/D3 receptor agonist, in protecting dopaminergic PC12 cells treated with buthionine sulfoximine (BSO), an inhibitor of key enzyme in glutathione synthesis and 6-hydroxydopamine (6-OHDA), a widely used neurotoxin. D-512 was able to restore level of glutathione against BSO/6-OHDA-mediated glutathione depletion. D-512 also showed significant neuroprotection in PC12 cells against toxicity induced by combined treatment of BSO and 6-OHDA. Furthermore, D-512 was able to restore both phospho-extracellular signal-regulated kinase and phospho-Jun N-terminal kinase levels upon treatment with 6-OHDA providing an evidence on the possible mechanism of action for neuroprotection by modulating mitogen-activated protein kinases. We have further demonstrated the neuroprotective effects of D-512 against oxidative insult produced by BSO and 6-OHDA in PC12 cells.

Multifunctional D2/D3 agonist D-520 with high in vivo efficacy: modulator of toxicity of alpha-synuclein aggregates.

We have developed a series of dihydroxy compounds and related analogues based on our hybrid D2/D3 agonist molecular template to develop multifunctional drugs for symptomatic and neuroprotective treatment for Parkinson's disease (PD). The lead compound (-)-24b (D-520) exhibited high agonist potency at D2/D3 receptors and produced efficacious activity in the animal models for PD. The data from thioflavin T (ThT) assay and from transmission electron microscopy (TEM) analysis demonstrate that D-520 is able to modulate aggregation of alpha-synuclein (αSN). Additionally, coincubation of D-520 with αSN is able to reduce toxicity of preformed aggregates of αSN compared to control αSN alone. Finally, in a neuroprotection study with dopaminergic MN9D cells, D-520 clearly demonstrated the effect of neuroprotection from toxicity of 6-hydroxydopamine. Thus, compound D-520 possesses properties characteristic of multifunctionality conducive to symptomatic and neuroprotective treatment of PD.

The high-affinity D2/D3 agonist D512 protects PC12 cells from 6-OHDA-induced apoptotic cell death and rescues dopaminergic neurons in the MPTP mouse model of Parkinson's disease.

In this study, in vitro and in vivo experiments were carried out with the high-affinity multifunctional D2/D3 agonist D-512 to explore its potential neuroprotective effects in models of Parkinson's disease and the potential mechanism(s) underlying such properties. Pre-treatment with D-512 in vitro was found to rescue rat adrenal Pheochromocytoma PC12 cells from toxicity induced by 6-hydroxydopamine administration in a dose-dependent manner. Neuroprotection was found to coincide with reductions in intracellular reactive oxygen species, lipid peroxidation, and DNA damage. In vivo, pre-treatment with 0.5 mg/kg D-512 was protective against neurodegenerative phenotypes associated with systemic administration of MPTP, including losses in striatal dopamine, reductions in numbers of DAergic neurons in the substantia nigra (SN), and locomotor dysfunction. These observations strongly suggest that the multifunctional drug D-512 may constitute a novel viable therapy for Parkinson's disease.

Topical delivery of anti-TNFα siRNA and capsaicin via novel lipid-polymer hybrid nanoparticles efficiently inhibits skin inflammation in vivo.

The barrier properties of the skin pose a significant but not insurmountable obstacle for development of new effective anti-inflammatory therapies. The objective of this study was to design and evaluate therapeutic efficacy of anti-nociception agent Capsaicin (Cap) and anti-TNFα siRNA (siTNFα) encapsulated cyclic cationic head lipid-polymer hybrid nanocarriers (CyLiPns) against chronic skin inflammatory diseases. Physico-chemical characterizations including hydrodynamic size, surface potential and entrapment efficacies of CyLiPns were found to be 163±9nm, 35.14±8.23mV and 92% for Cap, respectively. In vitro skin distribution studies revealed that CyLiPns could effectively deliver FITC-siRNA up to 360µm skin depth. Further, enhanced (p<0.001) Cap permeation from CyLiPns was observed compared to Capsaicin-Solution and Capzasin-HP. Therapeutic efficacies of CyLiPns were assessed using imiquamod-induced psoriatic plaque like model. CyLiPns carrying both Cap and siTNFα showed significant reduced expression of TNFα, NF-κB, IL-17, IL-23 and Ki-67 genes compared to either drugs alone (p<0.05) and were in close comparison with Topgraf®. Collectively these findings support our notion that novel cationic lipid-polymer hybrid nanoparticles can efficiently carry siTNFα and Cap into deeper dermal milieu and Cap with a combination of siTNFα shows synergism in treating skin inflammation.