Preclinical Efficacy of Cabazitaxel Loaded Poly(2-alkyl cyanoacrylate) Nanoparticle Variants.

Background: Biodegradable poly(alkyl cyanoacrylate) (PACA) nanoparticles (NPs) are receiving increasing attention in anti-cancer nanomedicine development not only for targeted cancer chemotherapy, but also for modulation of the tumor microenvironment. We previously reported promising results with cabazitaxel (CBZ) loaded poly(2-ethylbutyl cyanoacrylate) NPs (PEBCA-CBZ NPs) in a patient derived xenograft (PDX) model of triple-negative breast cancer, and this was associated with a decrease in M2 macrophages. The present study aims at comparing two endotoxin-free PACA NP variants (PEBCA and poly(2-ethylhexyl cyanoacrylate); PEHCA), loaded with CBZ and test whether conjugation with folate would improve their effect. Methods: Cytotoxicity assays and cellular uptake of NPs by flow cytometry were performed in different breast cancer cells. Biodistribution and efficacy studies were performed in PDX models of breast cancer. Tumor associated immune cells were analyzed by multiparametric flow cytometry. Results: In vitro studies showed similar NP-induced cytotoxicity patterns despite difference in early NP internalization. On intravenous injection, the liver cleared the majority of NPs. Efficacy studies in the HBCx39 PDX model demonstrated an enhanced effect of drug-loaded PEBCA variants compared with free drug and PEHCA NPs. Furthermore, the folate conjugated PEBCA variant did not show any enhanced effects compared with the unconjugated counterpart which might be due to unfavorable orientation of folate on the NPs. Finally, analyses of the immune cell populations in tumors revealed that treatment with drug loaded PEBCA variants affected the myeloid cells, especially macrophages, contributing to an inflammatory, immune activated tumor microenvironment. Conclusion: We report for the first time, comparative efficacy of PEBCA and PEHCA NP variants in triple negative breast cancer models and show that CBZ-loaded PEBCA NPs exhibit a combined effect on tumor cells and on the tumor associated myeloid compartment, which may boost the anti-tumor response.

Mechanism of cellular uptake and cytotoxicity of paclitaxel loaded lipid nanocapsules in breast cancer cells.

Lipid nanocapsules (LNCs) have proven their efficacy in delivering different drugs to various cancers, but no studies have yet described their uptake mechanisms, paclitaxel (PTX) delivery or resulting cytotoxicity towards breast cancer cells. Herein, we report results concerning cellular uptake of LNCs and cytotoxicity studies of PTX-loaded LNCs (LNCs-PTX) on the three breast cancer cell lines MCF-7, MDA-MB-231 and MDA-MB-468. LNCs-PTX of sizes 50 ± 2 nm, 90 ± 3 nm and 120 ± 4 nm were developed by the phase inversion method. Fluorescence microscopy and flow cytometry were used to observe the uptake of fluorescently labeled LNCs and cellular uptake of LNCs-PTX was measured using HPLC analyses of cell samples. These studies revealed a higher uptake of LNCs-PTX in MDA-MB-468 cells than in the other two cell lines. Moreover, free PTX and LNCs-PTX exhibited a similar pattern of toxicity towards each cell line, but MDA-MB-468 cells appeared to be more sensitive than the other two cell lines, as evaluated by the MTT cytotoxicity assay and a cell proliferation assay based upon [3H]thymidine incorporation. Studies with inhibitors of endocytosis indicate that the cellular uptake is mainly via the Cdc42/GRAF-dependent endocytosis as well as by macropinocytosis, whereas dynamin-dependent processes are not required. Furthermore, our results indicate that endocytosis of LNCs-PTX is important for the toxic effect on cells. Western blot analysis revealed that LNCs-PTX induce cytotoxicity by means of apoptosis in all the three cell lines. Altogether, the results demonstrate that LNCs-PTX exploit different mechanisms of endocytosis in a cell-type dependent manner, and subsequently induce apoptotic cell death in the breast cancer cells here studied. The article also describes biodistribution studies following intravenous injection of fluorescently labeled LNCs in mice.

Curcumin-Loaded Nanostructure Hybrid Lipid Capsules for Co-eradication of Breast Cancer and Cancer Stem Cells with Enhanced Anticancer Efficacy.

Co-eradication of cancer stem cells (CSCs) along with cancer cells have emerged as an immediate necessity to combat the rapid progression, therapeutic resistance, and relapse of cancer. Curcumin (CMN) has been well established for anticancer activity against a variety of cancers with an ability to eliminate CSCs. In spite of its extensive therapeutic potential, clinical applicability is impeded due to its highly hydrophobic nature. In this study, we developed CMN-loaded nanostructure hybrid lipid capsules (CMN-nHLCs) of three sizes (25, 75, and 150 nm) with 4% (w/w) loading capacity using our low-temperature (LT) method. Molecular interaction between different ingredients using fourier transform infrared (FTIR) analysis shows self-arrangement of ingredients into CMN-loaded nHLCs without any chemical bonding. CMN-nHLCs show a controlled release of CMN from nHLCs at 37 °C and long-term storage stability at 4 °C. CMN-nHLCs show ∼2.5-fold enhanced anticancer efficacy compared to free CMN in breast cancer cells (non-bCSCs) and breast cancer stem-like cells (bCSCs). CMN-nHLCs are effectively internalized into MCF-7 cells (non-bCSCs and bCSCs) and cause significant reduction in their mammosphere size/number and stemness. nHLCs provide improved physicochemical properties of CMN and superior anticancer efficacy by co-eradiating both non-bCSCs and bCSCs, suggesting a promising candidature of CMN-nHLCs for breast cancer treatment.

Epithelial Mesenchymal Transition in Cancer Progression: Prev entive Phytochemicals.

BACKGROUND: Epithelial-Mesenchymal Transition (EMT) is the conversion of epithelial cells into mesenchymal phenotype generally observed during embryogenesis and wound healing as well as in malignant transformation. Several signaling pathways and transcription factors associated with EMT have been explored. Dietary phytochemicals that are multi-targeted agents which interfere with these pathways, assume preventive potential against pathologic EMT. OBJECTIVE: The present review aims to provide a detailed description of the nature and characteristics of EMT in physiological and pathophysiological conditions and the scope of phytochemicals in its prevention. METHOD: Details regarding the initiation, progression as well as prevention of pathologic EMT and metastasis and recent patents on preventive phytochemicals were obtained from PubMed literatures and patent databases. RESULTS: The phenotypic changes during EMT are regulated by transcription factors like Snail, Slug, Twist and Zeb, which are activated through diverse signaling pathways of TGF-ß, NF-kB, Wnt and Notch. s phytocompounds that are potent enough to interfere with these signaling pathways, which in turn prevent pathological implications of EMT. Present review also discusses 28 recent patents on those phytocompounds. CONCLUSION: EMT is a significant pharmacological target for developing preventive agents to combat pathological conditions like malignancy. Many of the phytochemicals cited in this review are being enrolled for different phases of clinical trials for their efficacy. In spite of the major limitations regarding bioavailability, sensitivity and tolerance of these compounds, their synthetic analogs, formulations and efficient drug delivery systems are also being attempted which will hopefully generate productive and promising results in near future.