Studies in molecular modeling, in-vitro CDK2 inhibition and antimetastatic activity of some synthetic flavones.

Naturally occurring flavonoids have been shown to possess anticancer activity. We have previously shown that certain synthetic flavonoids also exert significant antiproliferative potential in MOLT-4, MCF-7, and HepG2 cell lines. To this end, we evaluated eight synthetic flavones for their CDK2 binding by molecular docking. Most flavones showed interaction with Leu 83. Based on docking and antiproliferative activity, we chose 3'-nitroflavone and 3', 5'-dimethoxyflavone for the molecular dynamics (MD) simulation and CDK2 inhibition studies. MD simulation studies confirmed interactions with CDK2 (as observed in docking). Furthermore, the inhibitory activities of CDK2/cyclin A2 enzyme for 3'-nitroflavone and 3', 5'-dimethoxyflavone were found to be 6.17 and 7.19 �M, respectively. 3'-nitroflavone and 3', 5'-dimethoxyflavone displayed moderate activity in colony formation assay, wound-scratch assay, and Leighton tube studies. Based on these data, the synthesized flavones might have clinical potential as potential inhibitors of CDK2.

Thermosensitive PLA based nanodispersion for targeting brain tumor via intranasal route.

Delivery of drugs to the brain via nasal route has been studied by many researchers. However, low residence time, mucociliary clearance and enzymatically active environment of nasal cavity pose many challenges to successful nasal delivery of drugs. We aim to deliver methotrexate by designing thermosensitive nanodispersion exhibiting enhanced residence time in nasal cavity and bypassing the blood brain barrier (BBB). PLA nanoparticles were developed using solvent evaporation technique. The developed nanoparticles were further dispersed in prepared thermosensitive vehicle of poloxamer 188 and Carbopol 934 to impart the property of increased residence time. The formulated nanoparticles demonstrated no interaction with the simulated nasal fluids (SNF), mucin, serum proteins and erythrocytes which demonstrate the safety of developed formulation for nasal administration. The penetration property of nanoparticles though the nasal mucosa was higher than the pure drug due to low mucociliary clearance. The developed nanoparticles diffused though the membrane pores and rapidly distributed into the brain portions compared to the pure drug. There was detectable and quantifiable amount of drug seen in the brain as demonstrated by in vivo brain distribution studies with considerably low amount of drug deposition in the lungs. The pharmacokinetic parameters demonstrated the enhancement in circulation half life, area under curve (AUC) and Cmax of the drug when administered intranasal in encapsulated form. Thus, the thermosensitive nanodispersions are surely promising delivery systems for delivering anticancer agents though the nasal route for potential treatment of brain tumors.

Docetaxel in cationic lipid nanocapsules for enhanced in vivo activity.

The usefulness of Docetaxel (DT) as an anti-cancer agent is limited to parenteral route owing to its very poor oral bioavailability. Thus, to improve its oral efficacy, DT was loaded in novel cationic lipid nanocapsules (DT CLNC). The DT CLNC possessed size of 130-150 nm, zeta potential of +72mV, adequate DT loading and over 95% encapsulation efficiency. TEM revealed capsular structure of DT CLNC. Lipolysis study indicated improved solubilization of DT by nanocapsules in comparison to DT solution. DT CLNC exhibited significantly higher release of DT in comparison to DT solution during in vitro permeation studies employing non-reverted rat-intestinal sac. Superior uptake of DT in zebra fishes exposed to DT CLNC resulted in greater apoptosis-based cell death as compared to those exposed to DT solution. This correlated well with the significantly superior (p < 0.05) anti-angiogenic activity of DT CLNC system over DT solution, in zebra fish model. DT CLNC also inhibited tumor growth in melanoma cell line induced tumors in C57BL/6 mice significantly, as compared to DT solution (p < 0.05). The DT CLNC system demonstrated adequate stability, with tremendous potential to improve oral efficacy of DT and can serve as an alternative to existing DT formulations available commercially for parenteral use.

Endogenous galectin-3 expression levels modulate immune responses in galectin-3 transgenic mice.

Galectin-3 (Gal-3), a ß-galactoside-binding mammalian lectin, is involved in cancer progression and metastasis. However, there is an unmet need to identify the underlying mechanisms of cancer metastasis mediated by endogenous host galectin-3. Galectin-3 is also known to be an important regulator of immune responses. The present study was aimed at analysing how expression of endogenous galectin-3 regulates host immunity and lung metastasis in B16F10 murine melanoma model. Transgenic Gal-3(+/-) (hemizygous) and Gal-3(-/-) (null) mice exhibited decreased levels of Natural Killer (NK) cells and lower NK mediated cytotoxicity against YAC-1 tumor targets, compared to Gal-3(+/+) (wild-type) mice. On stimulation, Gal-3(+/-) and Gal-3(-/-) mice splenocytes showed increased T cell proliferation than Gal-3(+/+) mice. Intracellular calcium flux was found to be lower in activated T cells of Gal-3(-/-) mice as compared to T cells from Gal-3(+/+) and Gal-3(+/-) mice. In Gal-3(-/-) mice, serum Th1, Th2 and Th17 cytokine levels were found to be lowest, exhibiting dysregulation of pro-inflammatory and anti-inflammatory cytokines balance. Marked decrease in serum IFN-γ levels and splenic IFN-γR1 (IFN-γ Receptor 1) expressing T and NK cell percentages were observed in Gal-3(-/-) mice. On recombinant IFN-γ treatment of splenocytes in vitro, Suppressor of Cytokine Signaling (SOCS) 1 and SOCS3 protein expression was higher in Gal-3(-/-) mice compared to that in Gal-3(+/+) and Gal-3(+/-) mice; suggesting possible attenuation of Signal Transducer and Activator of Transcription (STAT) 1 mediated IFN-γ signaling in Gal-3(-/-) mice. The ability of B16F10 melanoma cells to form metastatic colonies in the lungs of Gal-3(+/+) and Gal-3(-/-) mice remained comparable, whereas it was found to be reduced in Gal-3(+/-) mice. Our data indicates that complete absence of endogenous host galectin-3 facilitates lung metastasis of B16F10 cells in mice, which may be contributed by dysregulated immune responses resulting from decreased NK cytotoxicity, disturbed serum Th1, Th2, Th17 cytokine milieu, reduced serum IFN-γ levels and attenuation of splenic STAT1 mediated IFN-γ signalling in Gal-3(-/-) mice.

LeciPlex, invasomes, and liposomes: A skin penetration study.

The present study compares three vesicular systems, cationic LeciPlex, invasomes, and conventional liposomes for their ability to deliver drugs deep into the skin. Skin penetration ability of the three vesicular systems was studied for two drugs namely idebenone (antioxidant/anticancer) and azelaic acid (antiacne). All systems showed sizes in nanometer range with small polydispersity indices. Vesicular systems were characterized by CryoTEM studies to understand the differences in morphology of the vesicular systems. Ex vivo human skin penetration studies suggested a pattern in penetration of drugs in different layers of the skin: LeciPlex showed higher penetration for idebenone whereas invasomes showed higher penetration of azelaic acid. Ex vivo study using a fluorescent dye (DiI) was performed to understand the differences in the penetration behavior of the three vesicular systems on excised human skin. In vitro cytotoxicity studies on B16F10 melanoma cell lines revealed, when loaded with idebenone, LeciPlex formulations had the superior activity followed by invasomes and liposomes. In vitro antimicrobial study of azelaic acid loaded systems on Propionibacterium acne revealed high antimicrobial activity for DDAB leciplex followed by almost equal activity for invasomes and CTAB LeciPlex followed by liposomes. Whereas antiacne efficacy study in rats for azelaic acid loaded systems, invasomes exhibited the best antiacne efficacy followed by liposomes and LeciPlex.

Role of tumor cell surface lysosome-associated membrane protein-1 (LAMP1) and its associated carbohydrates in lung metastasis.

PURPOSE: Expression of lysosome-associated membrane protein-1 (LAMP1) on the surface correlates with metastatic potential of B16 melanoma cells. Downregulation of their expression in high metastatic (B16F10) cells reduced their surface expression and metastatic potential. Present investigations explore if overexpression of LAMP1 on the surface of low metastatic (B16F1) cells augment their metastatic ability, and if so, how? METHODS: B16F1 cells were transduced with lentiviral vector carrying mutant-LAMP1 (Y386A) (mutLAMP1). Surface expression of LAMP1 and carbohydrates was analyzed by flow cytometry, immunofluorescence and/or immunoprecipitation and Western blotting. Cell spreading and motility were assessed on components of extracellular matrix (ECM) (fibronectin) and basement membrane (BM) (matrigel), and galectin-3-coated coverslips/plates. Metastatic potential was assessed using experimental metastasis assay. RESULTS: Pre-incubation with anti-LAMP1 antibodies significantly reduced lung metastasis of B16F10 cells. Overexpression of mutLAMP1 significantly increased its surface expression on B16F1 cells, resulting in increased cellular spreading and motility on fibronectin and matrigel. LAMP1 is the major carrier of poly-N-acetyllactosamine (polyLacNAc) on B16F10 cells. However, significantly higher expression of mutLAMP1 had no effect on galectin-3 binding on cell surface or on spreading or motility of cells on galectin-3-coated coverslips/plates. These cells also failed to show any gain in metastatic ability. This could be because LAMP1 from these cells carried significantly lower levels of polyLacNAc in comparison with B16F10 cells. CONCLUSIONS: PolyLacNAc on B16F10 cells and galectin-3 on lungs are the major participants in melanoma metastasis. Although surface LAMP1 promotes interactions with organ ECM and BM, carbohydrates on LAMP1 play a decisive role in dictating lung metastasis.

Liposomes for targeting hepatocellular carcinoma: use of conjugated arabinogalactan as targeting ligand.

Present study investigates the potential of chemically modified (Shah et al., 2013) palmitoylated arabinogalactan (PAG) in guiding liposomal delivery system and targeting asialoglycoprotein receptors (ASGPR) which are expressed in hepatocellular carcinoma (HCC). PAG was incorporated in liposomes during preparation and doxorubicin hydrochloride was actively loaded in preformed liposomes with and without PAG. The liposomal systems with or without PAG were evaluated for in vitro release, in vitro cytotoxicity, in vitro cell uptake on ASGPR(+) cells, in vivo pharmacokinetic study, in vivo biodistribution study, and in vivo efficacy study in immunocompromised mice. The particle size for all the liposomal systems was below 200 nm with a negative zeta potential. Doxorubicin loaded PAG liposomes released significantly higher amount of doxorubicin at pH 5.5 as compared to pH 7.4, providing advantage for targeted tumor therapy. Doxorubicin in PAG liposomes showed superior cytotoxicity on ASGPR(+) HepG2 cells as compared to ASGPR(-), MCF7, A549, and HT29 cells. Superior uptake of doxorubicin loaded PAG liposomes as compared to doxorubicin loaded conventional liposomes was evident in confocal microscopy studies. Higher AUC in pharmacokinetic study and higher deposition in liver was observed for PAG liposomes compared to conventional liposomes. Significantly higher tumor suppression was noted in immunocompromised mice for mice treated with PAG liposomes as compared to the conventional liposomes. Targeting ability and superior activity of PAG liposomes is established pre-clinically suggesting potential of targeted delivery system for improved treatment of HCC.

Apoptosis induction and anti-cancer activity of LeciPlex formulations.

PURPOSE: Cationic agents have been reported to possess anti-neoplastic properties against various cancer cell types. However, their complexes with lipids appear to interact differently with different cancer cells. The purpose of this study was to (i) design and generate novel cationic lecithin nanoparticles, (ii) assess and understand the mechanism underlying their putative cytotoxicity and (iii) test their effect on cell cycle progression in various cancer-derived cell lines. In addition, we aimed to evaluate the in vivo potential of these newly developed nanoparticles in oral anti-cancer delivery. METHODS: Cationic lecithin nanoparticles were generated using a single step nanoprecipitation method and they were characterized for particle size, zeta potential, stability and in vitro release. Their cytotoxic potential was assessed using a sulforhodamine B assay, and their effect on cell cycle progression was evaluated using flow cytometry. The nanoparticle systems were also tested in vivo for their anti-tumorigenic potential. RESULTS: In contrast to cationic agents alone, the newly developed nanoformulations showed a specific toxicity against cancer cells. The mechanism of toxic cell death included apoptosis, S and G2/M cell cycle phase arrest, depending on the type of cationic agent and the cancer-derived cell line used. Both blank and drug-loaded systems exhibited significant anti-cancer activity, suggesting a synergistic anti-tumorigenic effect of the drug and its delivery system. CONCLUSIONS: Both in vitro and in vivo data indicate that cationic agents themselves exhibit broad anti-neoplastic activities. Complex formation of the cationic agents with phospholipids was found to provide specificity to the anti-cancer activity. These formulations thus possess potential for the design of effective anti-cancer delivery systems.

Galectin-3 expressed on different lung compartments promotes organ specific metastasis by facilitating arrest, extravasation and organ colonization via high affinity ligands on melanoma cells.

Interactions between molecules on the surface of tumor cells and those on the target organ endothelium play an important role in their arrest in an organ. Galectin-3 on the lung endothelium and high affinity ligands poly-N-acetyllactosamine (polyLacNAc) on N-oligosaccharides on melanoma cells facilitate such interactions. However, to extravasate and colonize an organ the cells must stabilize these interactions by spreading to retract endothelium, degrade exposed basement membrane (BM) and move into parenchyma and proliferate. Here, we show that galectin-3 is expressed on all the major compartments of the lungs and participates in not just promoting adhesion but also in spreading. We for the first time demonstrate that both soluble and immobilized galectin-3 induce secretion of MMP-9 required to breach vascular BM. Further, we show that immobilized galectin-3 is used as traction for the movement of cells. Downregulation of galactosyltransferases-I and -V resulted in significant loss in expression of polyLacNAc and thus reduced binding of galectin-3. This was accompanied with a loss in adhesion, spreading, MMP-9 secretion and motility of the cells on galectin-3 and thus their metastasis to lungs. Metastasis could also be inhibited by blocking surface polyLacNAc by pre-incubating cells with truncated galectin-3 (which lacked oligomerization domain) or by feeding mice with modified citrus pectin in drinking water. Overall, these results unequivocally show that polyLacNAc on melanoma cells and galectin-3 on the lungs play a critical role in arrest and extravasation of cells in the lungs and strategies that target these interactions inhibit lung metastasis.

Regulation of melanoma metastasis to lungs by cell surface Lysosome Associated Membrane Protein-1 (LAMP1) via galectin-3.

Lysosome Associated Membrane Protein-1 (LAMP1), which lines the lysosomes, is often found to be expressed on surface of metastatic cells. We previously demonstrated that its surface expression on B16 melanoma variants correlates with metastatic potential. To establish the role of cell surface LAMP1 in metastasis and to understand the possible mechanism by which it facilitates lung colonization, LAMP1 was downregulated in high metastatic B16F10 cells using shRNAs cloned in a doxycycline inducible vector. This also resulted in significantly decreased LAMP1 on the cell surface. Being a major carrier of poly-N-acetyllactosamine (polyLacNAc) substituted ß1,6 branched N-oligosaccharides, the high affinity ligands for galectin-3, LAMP1 down regulation also resulted in appreciably decreased binding of galectin-3 to the cell surface. LAMP1 has been shown to bind to Extracellular Matrix (ECM), Basement Membrane (BM) components and also to galectin-3 (via carbohydrates) which is known to get incorporated into the ECM and BM. Although, LAMP1 downregulation had a marginal effect on cellular spreading and motility on fibronectin and matrigel, it significantly altered the same on galectin-3, and ultimately leading to notably reduced lung metastasis. The results thus for the first time provide direct evidence that cell surface LAMP1 facilitates lung metastasis by providing ligands for galectin-3 which has been shown to be expressed in highest amounts on lungs and constitutively on its vascular endothelium.

Tamoxifen guided liposomes for targeting encapsulated anticancer agent to estrogen receptor positive breast cancer cells: in vitro and in vivo evaluation.

Tamoxifen (TMX), an estrogen receptor (ER) antagonist, incorporated at surface of liposomes loaded with Doxorubicin (DOX), was hypothesized to serve as ligand for targeting overexpressed ERs on surface and cytosol of breast cancer cells, in addition to its synergism with DOX in killing MCF-7 cells. The TMX-DOX liposomes demonstrated mean size of 188.8±2.2nm and positive potential of+47mV, both suitable for better cellular interaction. TMX-DOX liposomes sustained DOX release in vitro (25.9%) in pH 7.4 at 48h, in comparison with 64.5% DOX release at pH 5.5. In vitro cell line studies demonstrated that TMX-DOX liposomes were more cytotoxic to ER+ve MCF-7 cells as compared to DOX liposomes, DOX solution and TMX-DOX solution (P<0.05). However, there was no statistical difference in cyto-toxicity of TMX-DOX liposomes and DOX liposomes towards ER-ve MDA-MB-231 cells. Flow cytometry and confocal studies in MCF-7 cells revealed greater cell and nuclear uptake of DOX, with TMX guided liposomes as compared to DOX liposomes and DOX solution. TMX-DOX liposomes demonstrated significantly increased inhibition of MCF-7 cell based tumor growth in nude mice (P<0.05) in comparison to DOX solution and DOX liposomes, indicative of target specificity and higher DOX accumulation at tumor site.

Anti-neuropilin 1 antibody Fab' fragment conjugated liposomal docetaxel for active targeting of tumours.

Neuropilin-1, a transmembrane receptor entailed in wide range of human tumour cell lines and diverse neoplasms, mediates the effects of VEGF and Semaphorins during the processes of cellular proliferation, survival and migration. In view of this, we had developed and evaluated in vitro and in vivo efficacy of anti-neuropilin-1 immunoliposomes against neuropilin-1 receptor expressing tumours. The PEGylated liposomes loaded with docetaxel were prepared using thin film hydration method. Functionalised PEGylated liposomes were prepared using post-insertion technique. Anti-neuropilin-1 immunoliposomes were prepared by covalently conjugating Fab' fragments of neuropilin-1 antibody to functionalised PEGylated liposomes via thioether linkage. In vivo evaluation of Taxotere and liposomal formulations was performed using intradermal tumour model to demonstrate anti-angiogenic and tumour regression ability. The modified Fab' fragments and immunoliposomes were found to be immunoreactive against A549 cells. Further, docetaxel loaded PEGylated liposomes and PEGylated immunoliposomes demonstrated higher in vitro cytotoxicity than Taxotere formulation at the same drug concentration and exposure time. The live imaging showed distinctive cellular uptake of functional immunoliposomes. Further, significant decrease in micro-blood vessel density and tumour volumes was observed using bio-engineered liposomes. The results clearly highlight the need to seek neuropilin-1 as one of the prime targets in developing an anti-angiogenic therapy.

Etoposide loaded solid lipid nanoparticles for curtailing B16F10 melanoma colonization in lung.

Poor solubility of etoposide and associated poor bioavailability of the drug was circumvented by developing solid lipid nanocarrier system. The objective of the research work was to prepare etoposide loaded solid lipid nanoparticles (SLN) for improved efficacy and therapy of metastasized cancers. Entrapment of drug into nanoparticulate system modifies the pharmacokinetic and biodistribution profile of the drug with improved therapeutic efficacy. Solid lipid nanoparticles of various triglycerides were prepared using hot homogenization technique. Further, the process and formulation parameters viz. homogenization cycle and pressure, type of lipid were optimized. Developed nanoparticles were characterised for particle size, in vitro dissolution studies, DSC thermogram, surface morphology and cytotoxicity assay. Pharmacokinetic and biodistribution study were performed to assess the distribution of the drug in vivo. Modulation of the therapeutic activity of the drug was studied by performing antimetastatic activity on a B16F10 melanoma mouse model. The obtained results exhibited suitability of trimysristin for fabrication of nanoparticles. Characterisation of nanoparticles depicted formation of homogenous, spherical particles entrapping approximately 50% of the drug. The results for the performed MTT assay suggested that the developed nanoparticles exhibited cytotoxicity in a time- and concentration-dependent fashion. These findings concord with the results of the in vitro dissolution profile. Pharmacokinetic parameters demonstrated increase in area under curve (AUC), t1/2 and mean residence time (MRT) for drug in plasma. Further there is enhancement in the ratio of the drug that reaches to the highly perfused organs (upon encapsulation into solid lipid nanoparticles). Generally, cancer cells metastasized through the blood or lymphatic system. Accumulation of the drug in the highly perfused organ suggests suitability of the developed nanoparticles for targeting metastasized tumors. This was proved by the findings of the in vivo B16F10 mouse melanoma model. Improvement in the tumoricidal activity and survival rate of the animals substantiates the application of nanoparticles for improved therapeutic activity of etoposide.

Unraveling the cytotoxic potential of Temozolomide loaded into PLGA nanoparticles.

BACKGROUND: Nanotechnology has received great attention since a decade for the treatment of different varieties of cancer. However, there is a limited data available on the cytotoxic potential of Temozolomide (TMZ) formulations. In the current research work, an attempt has been made to understand the anti-metastatic effect of the drug after loading into PLGA nanoparticles against C6 glioma cells.Nanoparticles were prepared using solvent diffusion method and were characterized for size and morphology. Diffusion of the drug from the nanoparticles was studied by dialysis method. The designed nanoparticles were also assessed for cellular uptake using confocal microscopy and flow cytometry. RESULTS: PLGA nanoparticles caused a sustained release of the drug and showed a higher cellular uptake. The drug formulations also affected the cellular proliferation and motility. CONCLUSION: PLGA coated nanoparticles prolong the activity of the loaded drug while retaining the anti-metastatic activity.

Delineating the anti-metastatic potential of pentoxifylline in combination with liposomal doxorubicin against breast cancer cells.

Breast cancer remains the second most prevalent cancer worldwide. Several anticancer drugs are being currently used in the treatment of breast cancer. However, owing to high cytotoxicity, induced resistance and cost ineffectiveness, there is an urgent need to develop newer therapeutic regimens that limit the current problems. One of the approaches in this regard is the formulation of combination therapies whereby multiple drugs are being delivered at relatively lesser dose that surely confines the aforesaid problems. In this purview, we had evaluated the effects of pentoxifylline, a methylxanthine derivative and liposomal doxorubicin (Lipodox), an anthracycline in combination to evaluate their anti-metastatic activities both in vitro and in vivo against breast cancer cells. The combination regime exhibited synergistic activity and inhibited cellular proliferation to a greater extent with regard to each drug used alone.

Pentoxifylline regulates the cellular adhesion and its allied receptors to extracellular matrix components in breast cancer cells.

Pentoxifylline (PTX) is a methylxanthine derivative that improves blood flow by decreasing its viscosity. Being an inhibitor of platelet aggregation, it can thus reduce the adhesiveness of cancer cells prolonging their circulation time. This delay in forming secondary tumours makes them more prone to immunological surveillance. Recently, we have evaluated its anti-metastatic efficacy against breast cancer, using MDA-MB-231 model system. In view of this, we had ascertained the effect of PTX on adhesion of MDA-MB-231 cells to extracellular matrix components (ECM) and its allied receptors such as the integrins. PTX affected adhesion of breast cancer cells to matrigel, collagen type IV, fibronectin and laminin in a dose dependent manner. Further, PTX showed a differential effect on integrin expression profile. The experimental metastasis model using NOD-SCID mice showed lesser tumour island formation when treated with PTX compared to the control. These findings further substantiate the anti-adhesive potential of PTX in breast cancer and warrant further insights into the functional regulation.

Role of STAT3 in cancer metastasis and translational advances.

Signal transducer and activator of transcription 3 (STAT3) is a latent cytoplasmic transcription factor, originally discovered as a transducer of signal from cell surface receptors to the nucleus. It is activated by tyrosine phosphorylation at position 705 leading to its dimerization, nuclear translocation, DNA binding, and activation of gene transcription. Under normal physiological conditions, STAT3 activation is tightly regulated. However, compelling evidence suggests that STAT3 is constitutively activated in many cancers and plays a pivotal role in tumor growth and metastasis. It regulates cellular proliferation, invasion, migration, and angiogenesis that are critical for cancer metastasis. In this paper, we first describe the mechanism of STAT3 regulation followed by how STAT3 is involved in cancer metastasis, then we summarize the various small molecule inhibitors that inhibit STAT3 signaling.

Lipid colloidal carriers for improvement of anticancer activity of orally delivered quercetin: formulation, characterization and establishing in vitro-in vivo advantage.

Novel lipid nanocarriers, GeluPearl (GP) comprising of Precirol ATO 5 lipid nanoparticles with (GPNLC) or without oil (GPSLN), loaded with Quercetin (QR), were successfully fabricated to improve therapeutic efficacy. QR loaded GP nanoparticles were optimized to yield adequate colloidal stability, mean particle size in range of 350-380 nm and entrapment efficiency of more than 90%. GPSLN and GPNLC were characterized for morphological evaluation by virtue of cryo-TEM, surface charge, protection offered to QR against alkali mediated degradation and fluorescence studies to evaluate QR-lipid interaction. DSC analysis was performed to get insight into physical state of QR loaded in nanosystems. The in vitro release studies demonstrated sustained drug release potential of QR loaded GP. In vitro lipolysis studies confirmed that lipidic nanocarriers can improve QR solubilization. QR loaded GP nanosystems significantly (P < 0.05) reduced flank tumor volumes in C57BL/6 mice over a 22 day study period compared to QR suspension. GPSLN significantly reduced lung colonization and enhanced antimetastatic activity (P < 0.05) of drug against B16F10 melanoma cells in C57BL/6 mice as compared to QR suspension. QR loaded GPSLN and GPNLC could be effectively lyophilized without much change in particle size and drug content using 15% w/v mannitol as cryoprotectant.

Curbing the focal adhesion kinase and its associated signaling events by pentoxifylline in MDA-MB-231 human breast cancer cells.

Pentoxifylline (PTX) is a methylxanthine derivative currently being used in the treatment of peripheral vascular diseases. Recently, we had evaluated its action in human MDA-MB-231 breast cancer cells. PTX exhibited anti-metastatic activity by affecting key processes such as proliferation, adhesion, migration, invasion and apoptosis. In light of the preliminary findings, the present work accounts for the possible mechanistic insights of the pathways affected by PTX. Aberrant Focal Adhesion Kinase (FAK) signaling forms a key determinant in breast cancer and in view of this fact we had investigated downstream processes regulated by FAK. PTX at sub-toxic doses lowers the level of activated FAK, Extracellular Regulated Kinase or Mitogen Activated Protein Kinase (ERK/MAPK), Protein Kinase B (PKB/Akt) affecting cellular proliferation and survival. It blocks G1/S phase of cell cycle by inhibiting the expression of Cyclin D1/Cdk6. Further, it modulates the activities of RhoGTPases and alters actin organization resulting in decreased motility. PTX also delays tumor growth and inhibited blood vessel formation in vivo. In purview of these findings, PTX surely qualifies as a suitable prospect in the intervention of breast cancer.

Is an alternative drug delivery system needed for docetaxel? The role of controlling epimerization in formulations and beyond.

PURPOSE: The presence of 7-epidocetaxel in docetaxel injection and in vivo epimerisation has been reported to be the cause for development of tumor resistance to chemotherapy including docetaxel by inducing tumor cell protein cytochrome P450 1B1. The objective of this study was to determine systemic toxicity of Taxotere® containing 10% 7-epidocetaxel and to develop PEGylated liposomal injection that could resist epimerization in vivo. Another need for PEGylated liposomal delivery of docetaxel is to avoid reported hypersensitivity reactions of marketed products like Taxotere® and Duopafei® containing high concentration of tween-80. METHODS: The PEGylated liposomes loaded with docetaxel were prepared using thin film hydration method. The in vivo toxicity of Taxotere® containing 10% 7-epimer was studied in B16F10 experimental metastasis model. RESULTS: B16F10 experimental metastasis model using C57BL/6 mice injected with Taxotere® containing 10% 7-epimer showed higher weight loss as compared to Taxotere® containing no epimer at single dose of 40 mg/kg indicating higher systemic toxicity. Incubation of PEGylated liposomes with phosphate buffer saline (pH 7.4) containing 0.1% w/v Tween-80 for 48 h showed better resistance to docetaxel degradation when compared with Taxotere® injection indicating better in vivo stability of liposomal docetaxel. In addition, PEGylated liposomes showed enhanced in vitro cytotoxicity, against A549 and B16F10 cells, than Taxotere®. CONCLUSION: We can therefore expect less in vivo conversion of liposomal loaded docetaxel into 7-epimer, more passive targeting to tumor tissues, decreased 7-epimer induced systemic toxicity and tumor resistance to chemotherapy compared to Taxotere®. Further in vivo studies are needed to ascertain these facts.