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

Exploring the World of Curcumin: Photophysics, Photochemistry, and Applications in Nanoscience and Biology

Curcumin is a bright yellow naturally occurring polyphenol which is the principal component of turmeric. It is used as herbal supplement, cosmetics ingredient, and food coloring agent. Over the years, the therapeutic properties of the natural product curcumin have gone unexploited but not unnoticed. Curcumin cannot be employed as a drug due to limitations such as low aqueous solubility and limited bioavailability. Many attempts have been made to overcome these limitations by confining the drug in various confined media to enhance its bioavailability. The biomolecule is emissive and undergoes fundamental excited state processes such as solvation dynamics and excited state intramolecular proton transfer (ESIPT). Curcumin based biomaterials and nanomaterials are also a fast advancing field where curcumin is an intrinsic component necessary for formation of these materials and no longer added as an external free drug. In this review, we will summarize the recent research on the photophysical and photochemical properties of curcumin and its excited state dynamics in various bio-mimicking systems. At the same time we wish to also incorporate the various applications of curcumin, especially in biology. Lastly due to the growing importance of materials science, we will briefly discuss some recent advances on curcumin based biomaterials and nanomaterials. We believe such a compilation of recent research surrounding curcumin will provide an overall understanding of its potentialities in different areas.

Design and fabrication of functionalized curdlan-curcumin delivery system to facilitate the therapeutic effects of curcumin on breast cancer

We developed a facile method for the fabrication of a biodegradable delivery system composed of two blocks: curdlan and curcumin. This was achieved by chemical functionalization of curdlan through tosylation, amination followed by complexation with curcumin. A comprehensive evaluation of structural characterization and component stability showed that cur-cum complex exhibited better anticancer properties with enhanced thermal properties. The cur-cum complex shows pH sensitive sustained release behaviour with higher release at acidic pH and kinetic data of drug release follows the Korsmeyer-Peppas model. The cur-cum complex has ability to block the proliferation of the MCF-7 cell line as revealed by MTT assay which showed increased toxicity of cur-cum complex against these cell lines. The results obtained from western blot analysis demonstrated that the co-administration of cur and cum effectively induced apoptosis in MCF-7 cells. This effect was observed by a considerable upregulation of the Bcl-2/Bax ratio, a decline in mRNA expression of LDHA, level of lactate and LDH activity. The results clearly depict the role of functionalized curdlan as efficient carrier for curcumin delivery with prolonged, sustained release and enhanced bioavailability, thereby improving the overall anticancer activity.

Hybrid Lipid Nanocapsules: A Robust Platform for mRNA Delivery

The success of the mRNA vaccine against COVID-19 has garnered significant interest in the development of mRNA therapeutics against other diseases, but there remains a strong need for a stable and versatile delivery platform for these therapeutics. In this study, we report on a family of robust hybrid lipid nanocapsules (hLNCs) for the delivery of mRNA. The hLNCs are composed of kolliphore HS15, labrafac lipophile WL1349, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), and a conjugate of oleic acid (OA) and polyethylenimines of varying size (PEI─0.8, 1.8, and 25 kDa). They are prepared by a solvent-free, temperature-phase inversion method, yielding an average size of ∼40 nm and a particle distribution index (PDI) < 0.2. We demonstrate that the PDI remains <0.2 over a wide pH range and in a wide range of medium. We further show that the PDI and the functionality of mRNA condensed on the particles are robust to drying in a sugar glass and subsequent rehydration. Finally, we demonstrate that mRNA-loaded hLNCs yield reasonable transfection in vitro and in vivo settings.

Overcoming multidrug resistance by reversan and exterminating glioblastoma and glioblastoma stem cells by delivering drug-loaded nanostructure hybrid lipid capsules (nHLCs)

Glioblastoma multiforme (GBM) is regarded as a highly aggressive brain cancer with a poor prognosis. There is an increase in the expression of P-glycoprotein (P-gp), responsible for multidrug resistance (MDR), making it a potential target for improving drug responses. Additionally, glioblastoma stem cells (GSCs) increase resistance to chemo- and radiotherapy and play a major role in cancer relapse. In this study, we targeted P-gp using a small molecule inhibitor, reversan (RV), to inhibit MDR that prolonged the retention of drugs in the cytosolic milieu. To eliminate GBM and GSCs, we have used two well-established anti-cancer drugs, regorafenib (RF) and curcumin (CMN). To improve the pharmacokinetics and decrease systemic delivery of drugs, we developed nanostructure hybrid lipid capsules (nHLCs), where hydrophobic drugs can be loaded in the core, and their physicochemical properties were determined by dynamic light scattering (DLS) and cryo-scanning electron microscopy (SEM). Inhibition of MDR by RV has also shown enhanced retention of nHLC in GBM cells. Co-delivery of drug-loaded nHLCs, pre-treated with RV, exhibited superior cytotoxicity in both GBM and GSCs than their individual doses and effectively reduced the size and stemness of tumor spheres and accelerated the rate of apoptosis, suggesting a promising treatment for glioblastoma.

Reversal of Multidrug Resistance by the Synergistic Effect of Reversan and Hyperthermia to Potentiate the Chemotherapeutic Response of Doxorubicin in Glioblastoma and Glioblastoma Stem Cells

The glioblastoma stem cell (GSC) population in glioblastoma multiforme (GBM) poses major complication in clinical oncology owing to increased resistance to chemotherapeutic drugs, thereby limiting treatment in patients with recurring glioblastoma. To completely eradicate glioblastoma, a single therapy module is not enough; therefore, there is a need to develop a multimodal approach to eliminate bulk tumors along with the CSC population. With an aim to target transporters associated with multidrug resistance (MDR), such as P-glycoprotein (P-gp), a small-molecule inhibitor, reversan (RV) was used along with multifunctional magnetic nanoparticles (MNPs) for hyperthermia (HT) therapy and targeted drug delivery. Higher efflux of free doxorubicin (Dox) from the cells was stabilized by encapsulation in PPS-MnFe nanoparticles, whose physicochemical properties were determined by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Treatment with RV also enhanced the cellular uptake of PPS-MnFe-Dox, whereas RV and magnetic hyperthermia (MHT) together showed prolonged retention of fluorescence dye, Rhodamine123 (R123), in glioblastoma cells compared with individual treatment. Overall, in this work, we demonstrated the synergistic action of RV and HT to combat MDR in GBM and GSCs, and chemo-hyperthermia therapy enhanced the cytotoxic effect of the chemotherapeutic drug Dox (with lower effective concentration) and induced a higher degree of apoptosis compared to single-drug dosage.

Therapeutic vulnerabilities of cancer stem cells and effects of natural products

Covering: 1995 to 2022Tumors possess both genetic and phenotypic heterogeneity leading to the survival of subpopulations post-treatment. The term cancer stem cells (CSCs) describes a subpopulation that is resistant to many types of chemotherapy and which also possess enhanced migratory and anchorage-independent growth capabilities. These cells are enriched in residual tumor material post-treatment and can serve as the seed for future tumor re-growth, at both primary and metastatic sites. Elimination of CSCs is a key goal in enhancing cancer treatment and may be aided by application of natural products in conjunction with conventional treatments. In this review, we highlight molecular features of CSCs and discuss synthesis, structure-activity relationships, derivatization, and effects of six natural products with anti-CSC activity.

Polypropylene sulphide coating on magnetic nanoparticles as a novel platform for excellent biocompatible, stimuli-responsive smart magnetic nanocarriers for cancer therapeutics

Magnetic nanoparticle (MNP) delivery systems are promising for targeted drug delivery, imaging, and chemo-hyperthermia of cancer; however, their uses remain limited primarily due to their toxicity associated with reactive oxygen species (ROS) generation, targeted delivery, and biodegradation. Attempts employing polymer coatings to minimize the toxicity, along with other challenges, have had limited success. We designed a novel yet generic 'one-for-all' polypropylene sulphide (PPS) coated magnetic nano-delivery system (80 ± 15 nm) as a multi-faceted approach for significant biocompatibility improvement, loading of multiple drugs, ROS-responsive delivery, and combined chemo-hyperthermia therapy for biomedical applications. Three distinct MNP systems (15 ± 1 nm) were fabricated, coated with PPS polymer, and investigated to validate our hypothesis and design. Simultaneous degradation of MNPs and PPS coatings with ROS-scavenging characteristics boosted the biocompatibility of MNPs 2-3 times towards non-cancerous fibroblasts (NIH3T3) and human epithelial cells (HEK293). In an alternating magnetic field, PPS-MNPs (MnFe) had the strongest heating characteristics (SAR value of 240 W g^-1). PPS-MNP drug-loaded NPs were efficiently internalised into cells and released 80% of the drugs under tumor microenvironment-mimicking (pH 5-7, ROS) conditions, and demonstrated effective chemo-hyperthermia (45 °C) application for breast cancer cells with 95% cell death in combined treatment vs. 55% and 30% cell death in only hyperthermia and chemotherapy respectively.

Natural Products-Based Nanoformulations: A New Approach Targeting CSCs to Cancer Therapy

Cancer stem cells (CSCs) lead to the occurrence and progression of cancer due to their strong tumorigenic, self-renewal, and multidirectional differentiation abilities. Existing cancer treatment methods cannot effectively kill or inhibit CSCs but instead enrich them and produce stronger proliferation, invasion, and metastasis capabilities, resulting in cancer recurrence and treatment resistance, which has become a difficult problem in clinical treatment. Therefore, targeting CSCs may be the most promising approach for comprehensive cancer therapy in the future. A variety of natural products (NP) have significant antitumor effects and have been identified to target and inhibit CSCs. However, pharmacokinetic defects and off-target effects have greatly hindered their clinical translation. NP-based nanoformulations (NPNs) have tremendous potential to overcome the disadvantages of NP against CSCs through site-specific delivery and by improving their pharmacokinetic parameters. In this review, we summarize the recent progress of NPNs targeting CSCs in cancer therapy, looking forward to transforming preclinical research results into clinical applications and bringing new prospects for cancer treatment.

Lipid nanocapsules co-encapsulating paclitaxel and salinomycin for eradicating breast cancer and cancer stem cells

Cancer stem cells (CSCs) comprise a diminutive population of the tumor but pose major obstacles in cancer treatment, often their presence being correlated with poor prognosis, therapeutic resistance and relapse. Nanocarriers of combined drugs regimes demonstrate improved pharmacokinetics and decreased systemic toxicity by targeting the bulk tumor cells along with CSCs, holding the key to future successful chemotherapy. Herein, we developed lipid nanocapsules (LNCs) with co-encapsulated paclitaxel (PTX) and salinomycin (SAL) to eliminate breast cancer cells (MCF-7; non-bCSCs) and cancer stem cells (bCSCs) respectively. LNCs loaded with either PTX or SAL alone or in combination were fabricated by the phase inversion temperature (PIT) method. Physicochemical properties such as nano-size (90 ± 5 nm) and spherical morphology of LNCs were confirmed by dynamic light scattering (DLS) and scanning electron microscopy (SEM) respectively. More than 98 % encapsulation efficiency of drug, alone or in combination, and their controlled drug release was obtained. Drug loaded LNCs were efficiently internalized and exhibited cytotoxicity in non-bCSCs and bCSCs, with dual drug loaded LNCs offering superior cytotoxicity and anti-bCSCs property. Drug loaded nanocapsules induced apoptosis in bCSCs, potentiated with the co-delivery of paclitaxel and salinomycin. Synergistic cytotoxic effect on both cells, non-bCSCs and bCSCs and effective reduction of the tumor mammospheres growth by co-encapsulated paclitaxel and salinomycin suggest LNCs to be promising for treatment of breast cancer.

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.