Design and biological activity of novel stealth polymeric lipid nanoparticles for enhanced delivery of hydrophobic photodynamic therapy drugs.

Advances in in vivo stability and preferential tumor uptake of cancer nanomedicine are warranted for effective chemotherapy. Here, we describe a novel nanoformulation using an unconventional polymeric tubule-forming phospholipid, DC8,9PC. We report that DC8,9PC transitions to stable vesicles (LNPs) in the presence of PEGylated lipid (DSPE-PEG2000); the resulting DC8,9PC:DSPE-PEG2000 LNPs efficiently included a hydrophobic PDT drug, HPPH. Remarkably, these LNPs incorporated unusually high DSPE-PEG2000 concentrations; LNP10-HPPH and LNP20-HPPH (10 & 20 mol% PEGylated lipid, respectively) exhibited >90% serum stability at 37 °C. Increased PEGylation in the LNPs correlated with enhanced tumor accumulation in intravenously injected HT29 tumor mouse xenographs. Colon-26 bearing BALB/c mice, intravenously injected with LNP20-HPPH showed superior PDT efficacy and animal survival (no tumor recurrence up to 100 days) as compared to a formulation currently used in clinical trials. Taken together, we present a simple stealth binary lipid nanosystem with enhanced efficiency of tumor accumulation and superior therapeutic efficacy.

Targeted Nanoparticles for Fluorescence Imaging of Folate Receptor Positive Tumors.

This report presents the synthesis and folate receptor target-specificity of amino-functionalized polyacrylamide nanoparticles (AFPAA NPs) for near-infrared (NIR) fluorescence imaging of cancer. For the synthesis of desired nano-constructs, the AFPAA NPs (hereafter referred to as NPs) were reacted with a NIR cyanine dye (CD) bearing carboxylic acid functionality by following our previously reported approach, and the resulting conjugate (NP-CD) on further reaction with folic acid (FA) resulted in a new nano-construct, FA-NP-CD, which demonstrated significantly higher uptake in folate receptor-positive breast cancer cells (KB+) and in folate receptor over-expressed tumors in vivo. The target-specificity of these nanoparticles was further confirmed by inhibition assay in folate receptor-positive (KB+) and -negative (HT-1080) cell lines. To show the advantages of polyacrylamide (PAA)-based NPs in folate receptor target-specificity, the CD used in preparing the FA-NP-CD construct was also reacted with folic acid alone and the synthetic conjugate (CD-FA) was also investigated for its target-specificity. Interestingly, in contrast to NPs (FA-NP-CD), the CD-FA conjugate did not show any significant in vitro or in vivo specificity toward folate receptors, showing the advantages of PAA-based nanotechnology in delivering the desired agent to tumor cells.

Highlights on the imaging (nuclear/fluorescence) and phototherapeutic potential of a tri-functional chlorophyll-a analog with no significant toxicity in mice and rats.

Herein we report the positron emission tomography (PET) imaging potential of a 124I-labeled radiopharmaceutical (PET-ONCO). In tumored mice, it shows high uptake in a variety of tumors: brain (GL261, U87), Colon (Colon26), lung (Lewis lung), breast (4 T1), bladder (UMUC3), pancreas (PANC-1) implanted in mice. This agent also shows promise for imaging associated metastatic disease (breast to lung, to bone). Interestingly, the iodinated compound derived from chlorophyll-a, in combination with the corresponding 124I-analog, can serve as a dual imaging agent (PET/fluorescence, complimentary to each other), with an option of photodynamic therapy (PDT). In contrast to Fluorine-18 (half-life 110 min), the Iodine-124 radionuclide has a physical half-life of roughly 4 days. Thus, unlike 18F-FDG, PET-ONCO can be transported longer distances. While the time for optimal tumor-uptake was observed at 24 h, improved tumor contrasts of both primary and metastasis were obtained at 48 and 72 h post- injection (i. v.) of PET-ONCO. In both mice and rats at a single dose study, PET-ONCO did not show any organ toxicity.

A Pyropheophorbide Analogue Containing a Fused Methoxy Cyclohexenone Ring System Shows Promising Cancer-Imaging Ability.

Herein we report the synthesis, photophysical properties, positron emission tomography (PET) imaging and photodynamic therapy (PDT) efficacy of methyl 3-(1'-m-iodobenzyloxy)ethyl-3-devinyl-verdin 4 (with or without the 124 I isotope). The PET imaging ability and ex vivo biodistribution of [124 I]4 were compared with the well-studied methyl [3-(124 1'-m-iodobenzyloxy)ethyl]-3-devinyl-pyropheophorbide-a methyl ester (PET-ONCO or [124 I]2) and [18 F]fluorodeoxyglucose ([18 F]FDG) in BALB/c mice bearing colon-26 tumors. Whole-body PET images of [124 I]4 containing a fused methoxy cyclohexenone ring system showed excellent tumor contrast with time (72>48>24 h post-injection). Ex vivo biodistribution results indicate that relative to the current clinical standard [18 F]FDG and [124 I]2 in 2 % ethanol formulation, [124 I]4, at the same radioactive dose (25 µCi per mouse), showed higher tumor uptake at 24 h post-injection and longer tumor retention. In biological environments, compound 4 showed lower fluorescence and lower singlet oxygen yield than 2, which is possibly due to higher aggregation caused by the presence of a fused cyclohexenone ring system, resulting in limited in vitro/in vivo PDT efficacy. Therefore, the chlorophyll-a analogue [124 I]4 provides easy access to a novel PET imaging agent (with no skin phototoxicity) to image cancer types-brain, renal carcinomas, pancreas-in which [18 F]FDG shows limitations.

BDNF variation and mood disorders: a novel functional promoter polymorphism and Val66Met are associated with anxiety but have opposing effects.

The brain-derived neurotrophic factor (BDNF) gene is critical for neuronal function and survival, and is likely to be important in psychiatric disorders. In this study, we used single-nucleotide polymorphism (SNP) discovery, functional analyses, and genetic association studies to better understand the potential role of BDNF sequence variation in behavior. Screening 480 unrelated individuals for SNPs and genotyping was performed in US Caucasian, American Indian, and African American populations. Lifetime DSM-III-R psychiatric diagnoses were assigned and the Tridimensional Personality Questionnaire (TPQ) was administered to measure anxious temperament (harm avoidance (HA)) and novelty seeking (NS). A novel SNP (-281 C>A) in promoter 1 was discovered that had decreased DNA binding in vitro and decreased basal reporter gene activity in transfected rat hippocampal neurons. The frequency of the -281 A allele was 0.03 in a Caucasian sample, but was virtually absent in other populations. Association analyses in a community-based sample showed that individuals with the -281 A allele (13 heterozygotes) had lower TPQ HA (F=4.8, p<0.05). In contrast, the Met 66 allele was associated with increased HA (F=4.1, p=0.02) and was most abundant in individuals with both anxiety disorders and major depression (p<0.05). Among the Val66Val homozygotes, individuals who were -281 CA heterozygotes had significantly lower HA than the -281 CC homozygotes (p<0.01). Our results suggest that in this population, the low activity -281 A allele may be protective against anxiety and psychiatric morbidity, whereas Met 66 may be a risk allele.

Induction of glucose metabolism in stimulated T lymphocytes is regulated by mitogen-activated protein kinase signaling.

T lymphocytes play a critical role in cell-mediated immune responses. During activation, extracellular and intracellular signals alter T cell metabolism in order to meet the energetic and biosynthetic needs of a proliferating, active cell, but control of these phenomena is not well defined. Previous studies have demonstrated that signaling from the costimulatory receptor CD28 enhances glucose utilization via the phosphatidylinositol-3-kinase (PI3K) pathway. However, since CD28 ligation alone does not induce glucose metabolism in resting T cells, contributions from T cell receptor-initiated signaling pathways must also be important. We therefore investigated the role of mitogen-activated protein kinase (MAPK) signaling in the regulation of mouse T cell glucose metabolism. T cell stimulation strongly induces glucose uptake and glycolysis, both of which are severely impaired by inhibition of extracellular signal-regulated kinase (ERK), whereas p38 inhibition had a much smaller effect. Activation also induced hexokinase activity and expression in T cells, and both were similarly dependent on ERK signaling. Thus, the ERK signaling pathway cooperates with PI3K to induce glucose utilization in activated T cells, with hexokinase serving as a potential point for coordinated regulation.