Preclinical evaluation of mRNA trimannosylated lipopolyplexes as therapeutic cancer vaccines targeting dendritic cells.

Clinical trials with direct administration of synthetic mRNAs encoding tumor antigens demonstrated safety and induction of tumor-specific immune responses. Their proper delivery to dendritic cells (DCs) requires their protection against RNase degradation and more specificity for dose reduction. Lipid-Polymer-RNA lipopolyplexes (LPR) are attractive mRNA delivery systems and their equipment with mannose containing glycolipid, specific of endocytic receptors present on the membrane of DCs is a valuable strategy. In this present work, we evaluated the capacity of LPR functionalized with a tri-antenna of α-d-mannopyranoside (triMN-LPR) concerning (i) their binding to CD209/DC-SIGN and CD207/Langerin expressing cell lines, human and mouse DCs and other hematopoietic cell populations, (ii) the nature of induced immune response after in vivo immunization and (iii) their therapeutic anti-cancer vaccine efficiency. We demonstrated that triMN-LPR provided high induction of a local inflammatory response two days after intradermal injection to C57BL/6 mice, followed by the recruitment and activation of DCs in the corresponding draining lymph nodes. This was associated with skin production of CCR7 and CXCR4 at vaccination sites driving DC migration. High number of E7-specific T cells was detected after E7-encoded mRNA triMN-LPR vaccination. When evaluated in three therapeutic pre-clinical murine tumor models such as E7-expressing TC1 cells, OVA-expressing EG7 cells and MART-1-expressing B16F0 cells, triMN-LPR carrying mRNA encoding the respective antigens significantly exert curative responses in mice vaccinated seven days after initial tumor inoculation. These results provide evidence that triMN-LPR give rise to an efficient stimulatory immune response allowing for therapeutic anti-cancer vaccination in mice. This mRNA formulation should be considered for anti-cancer vaccination in Humans.

Evaluation of the transfection efficacies of quaternary ammonium salts prepared from sophorolipids.

Five quaternary ammonium amphiphilic compounds were synthesized from sophorolipid 1. These compounds were formulated in aqueous media and some of them (5 and 6) produced well-defined supramolecular aggregates which were characterized by DLS and zeta measurements. Their capacity to transfect four different eukaryotic cell lines in vitro was assessed. To evaluate the influence of the carbohydrate head group from the sophorolipids on the transfection efficacies, their deglycosylated analogues were also synthesized and tested for gene delivery. For all the compounds, the use of DOPE as a helper lipid in a 1 : 1 molar ratio with the ammonium-based lipids was required to obtain homogeneous formulations. The transfection results indicate that quaternary ammonium-based sophorolipids proved to be more efficient pDNA carriers than their deglycosylated counterparts. Moreover, the presence of the carbohydrate head group clearly contributed to the good biocompatibility of these cationic lipids. These cationic sophorolipid derivatives thus offer good potential for the development of new vectors for gene delivery based on renewable resources.

La1-xLnxH(O3PCH3)2 (Ln = Tb, Eu; 0 < x ≤ 1): an organic-inorganic hybrid with lanthanide chains and tunable luminescence properties.

The organic/inorganic La1-xLnxH(O3PCH3)2 (Ln = Eu, Tb) hybrids have been synthesized by hydrothermal synthesis. The crystal structure of LaH(O3PCH3)2 consists of chains of edge-sharing LaO8 polyhedra linked through PO3C tetrahedra. Photoluminescence of Eu(3+), Tb(3+) and Eu(3+)/Tb(3+) co-doped materials have been investigated. The Eu and Tb hybrids show no concentration quenching versus doping rate suggesting energy migration through a percolation model. The Eu hybrids exhibit a red emission while the Tb ones exhibit, with the Tb rate increasing, a blue to green emission under a 378 nm excitation wavelength and a cyan to green emission under a 262 nm excitation wavelength. The doping rate dependent red shift results from a cross relaxation phenomenon between closed Tb(3+) ions. The blue to cyan shift observed for the slightly doped materials, when excitation wavelength shifts from 378 nm to 262 nm, is due to different relaxation phenomena, from the (5)D3 level for a 378 nm excitation wavelength and from the (5)D4 level via the 4f5d level for a 262 nm excitation wavelength. Under a 378 nm wavelength, the co-doped La0.93Eu0.03Tb0.04H(O3PCH3)2 hybrid exhibits a white/cyan emission with CIE coordinates equal to x = 0.29, y = 0.37.

Targeting SKCa channels in cancer: potential new therapeutic approaches.

Many studies have reported changes in potassium channel expression in many cancers and the involvement of these channels in various stages of cancer progression. By contrast, data concerning SKCa channels (small conductance calcium-activated potassium channels) have only recently become available. This review aims i) to present the structure and physiology of SKCa channels, ii) to provide an overview of published data concerning the SKCa proteins produced in tumor cells, and, whenever possible, the biological function assigned to them and iii) to review previous and novel modulators of SKCa channels. SKCa channels are activated by low concentrations of intracellular calcium and consist of homo- or heteromeric assemblies of α-subunits named SK1, SK2 and SK3. SK2-3 channels are expressed in tumors and have been assigned a biological function in cancer cells: the enhancement of cell proliferation and cell migration by hijacking the functions of SK2 and SK3 channels, respectively. Two major classes of SKCa modulators have been described: toxins (apamin) and small synthetic molecules. Most SKCa blockers are pore blockers, but some modify the calcium sensitivity of SKCa channels without interacting with the apamin binding site. In this review, we present edelfosine and ohmline as atypical anticancer agents and novel SK3 inhibitors. Edelfosine and ohmline are synthetic alkyl-lipids with structures different from all previously described SKCa modulators. They should pave the way for the development of a new class of migration-targeted anticancer agents. We believe that such blockers have potential for use in the prevention or treatment of metastasis.

New alkyl-lipid blockers of SK3 channels reduce cancer cell migration and occurrence of metastasis.

Edelfosine is an inhibitor of SK3 channel mediated cell migration. However, this compound bears adverse in vivo side effects. Using cell SK3 dependent cell-migration assay, patch-clamp, (125)I-apamin binding, and in vivo experiments we tested the ability of 15 lipid derivatives with chemical structures inspired from edelfosine to inhibit SK3 channels. Using a structure-activity relationship approach we identified an edelfosine analog named Ohmline (1-O-hexadecyl- 2-O-methyl-sn-glycero-3-lactose) with potent inhibitory effects on the SK3 channel. Its potency was greater for SK3 channels than for SK1 channels; it did not affect IKCa channels and only slightly but not significantly affected SK2 channels. This is the first SKCa channel blocker that can be used to discriminate between SK2 and SK1/SK3 channels and represents a useful tool to investigate the functional role of SK3 channels in peripheral tissues (that do not express SK1 channels). This compound, which acts with an IC(50) of 300 nM, did not displace apamin from SKCa channels and had no effect on non-specific edelfosine targets such as protein kinase C (PKC), receptors for platelet activating factor (PAF) and lysophosphatidic acid (LPA), as well as non-cancerous cells. This is promising because the pitfalls associated with the use of edelfosine-like compounds have been that their effective and high concentrations are often cytotoxic due to their detergent-like character causing normal cell lysis. Finally, Ohmline reduced metastasis development in a mice model of tumor indicating that this compound could become a lead compound for the first class of lipid-antimetastatic agent.

A one step process for grafting organic pendants on alumina via the reaction of alumina and phosphonate under microwave irradiation.

Phosphonate esters react with gamma-alumina under microwave (MW) irradiation; this reaction is a simple preparative method to graft organic pendant groups onto the surface of alumina; the efficiency of the grafting was readily checked by solid-state NMR techniques (31P and 27Al).