Investigation of Intracellular Delivery of NuBCP-9 by Conjugation with Oligoarginines Peptides in MDA-MB-231 Cells

Emerging concepts in designing next-generation multifunctional nanomedicine for cancer treatment

Nanotherapy has emerged as an improved anticancer therapeutic strategy to circumvent the harmful side effects of chemotherapy. It has been proven to be beneficial to offer multiple advantages, including their capacity to carry different therapeutic agents, longer circulation time and increased therapeutic index with reduced toxicity. Over time, nanotherapy evolved in terms of their designing strategies like geometry, size, composition or chemistry to circumvent the biological barriers. Multifunctional nanoscale materials are widely used as molecular transporter for delivering therapeutics and imaging agents. Nanomedicine involving multi-component chemotherapeutic drug-based combination therapy has been found to be an improved promising approach to increase the efficacy of cancer treatment. Next-generation nanomedicine has also utilized and combined immunotherapy to increase its therapeutic efficacy. It helps in targeting tumor immune response sparing the healthy systemic immune function. In this review, we have summarized the progress of nanotechnology in terms of nanoparticle designing and targeting cancer. We have also discussed its further applications in combination therapy and cancer immunotherapy. Integrating patient-specific proteomics and biomarker based information and harnessing clinically safe nanotechnology, the development of precision nanomedicine could revolutionize the effective cancer therapy.

Amphiphilic Cell-Penetrating Peptides Containing Natural and Unnatural Amino Acids as Drug Delivery Agents

A series of cyclic peptides, [(DipR)(WR)₄], [(DipR)₂(WR)₃], [(DipR)₃(WR)₂], [(DipR)₄(WR)], and [DipR]₅, and their linear counterparts containing arginine (R) as positively charged residues and tryptophan (W) or diphenylalanine (Dip) as hydrophobic residues, were synthesized and evaluated for their molecular transporter efficiency. The in vitro cytotoxicity of the synthesized peptides was determined in human epithelial ovary adenocarcinoma cells (SK-OV-3), human lymphoblast peripheral blood cells (CCRF-CEM), human embryonic epithelial kidney healthy cells (HEK-293), human epithelial mammary gland adenocarcinoma cells (MDA-MB-468), pig epithelial kidney normal cells (LLC-PK1), and human epithelial fibroblast uterine sarcoma cells (MES-SA). A concentration of 5–10 µM and 3 h incubation were selected in uptake studies. The cellular uptake of a fluorescent-labeled phosphopeptide, stavudine, lamivudine, emtricitabine, and siRNA was determined in the presence of peptides via flow cytometry. Among the peptides, [DipR]₅ (10 µM) was found to be the most efficient transporter and significantly improved the uptake of F’-GpYEEI, i.e., by approximately 130-fold after 3 h incubation in CCRF-CEM cells. Confocal microscopy further confirmed the improved delivery of fluorescent-labeled [DipR]₅ (F’-[K(DipR)₅]) alone and F’-GpYEEI in the presence of [DipR]₅ in MDA-MB-231 cells. The uptake of fluorescent-labeled siRNA (F’-siRNA) in the presence of [DipR]₅ with N/P ratios of 10 and 20 was found to be 30- and 50-fold higher, respectively, compared with the cells exposed to F’-siRNA alone. The presence of endocytosis inhibitors, i.e., nystatin, chlorpromazine, chloroquine, and methyl β-cyclodextrin, did not completely inhibit the cellular uptake of F’-[K(DipR)₅] alone or F’-GpYEEI in the presence of [DipR]₅, suggesting that a combination of mechanisms contributes to uptake. Circular dichroism was utilized to determine the secondary structure, while transmission electron microscopy was used to evaluate the particle sizes and morphology of the peptides. The data suggest the remarkable membrane transporter property of [DipR]₅ for improving the delivery of various small molecules and cell-impermeable negatively charged molecules (e.g., siRNA and phosphopeptide).

Targeting TOR signaling for enhanced lipid productivity in algae

Microalgae can produce large quantities of triacylglycerols (TAGs) and other neutral lipids that are suitable for making biofuels and as feedstocks for green chemistry. However, TAGs accumulate under stress conditions that also stop growth, leading to a trade-off between biomass production and TAG yield. Recently, in the model marine diatom Phaeodactylum tricornutum it was shown that inhibition of the target of rapamycin (TOR) kinase boosts lipid productivity by promoting TAG production without stopping growth. We believe that basic knowledge in this emerging field is required to develop innovative strategies to improve neutral lipid accumulation in oleaginous microalgae. In this minireview, we discuss current research on the TOR signaling pathway with a focus on its control on lipid homeostasis. We first provide an overview of the well characterized roles of TOR in mammalian lipogenesis, adipogenesis and lipolysis. We then present evidence of a role for TOR in controlling TAG accumulation in microalgae, and draw parallels between the situation in animals, plants and microalgae to propose a model of TOR signaling for TAG accumulation in microalgae.