Natural products based nanoformulations for cancer treatment: Current evolution in Indian research

The use of medicinal plants is as ancient as human civilization. The development of phytochemistry and pharmacology facilitates the identification of natural bioactive compounds and their mechanisms of action, including against cancer. The efficacy and the safety of a bioactive compound depend on its optimal delivery to the target site. Most natural bioactive compounds (phenols, flavonoids, tannins, etc.) are unable to reach their target sites due to their low water solubility, less cellular absorption, and high molecular weight, leading to their failure into clinical translation. Therefore, many scientific studies are going on to overcome the drawbacks of natural products for clinical applications. Several studies in India, as well as worldwide, have proposed the development of natural products-based nanoformulations to increase their efficacy and safety profile for cancer therapy by improving the delivery of natural bioactive compounds to their target site. Therefore, we are trying to discuss the development of natural products-based nanoformulations in India to improve the efficacy and safety of natural bioactive compounds against cancer.

Efficient uptake and retention of iron oxide-based nanoparticles in HeLa cells leads to an effective intracellular delivery of doxorubicin

The purpose of this study was to construct and characterize iron oxide nanoparticles (IONP_CO) for intracellular delivery of the anthracycline doxorubicin (DOX; IONP_DOX) in order to induce tumor cell inactivation. More than 80% of the loaded drug was released from IONP_DOX within 24 h (100% at 70 h). Efficient internalization of IONP_DOX and IONP_CO in HeLa cells occurred through pino- and endocytosis, with both IONP accumulating in a perinuclear pattern. IONP_CO were biocompatible with maximum 27.9% ± 6.1% reduction in proliferation 96 h after treatment with up to 200 µg/mL IONP_CO. Treatment with IONP_DOX resulted in a concentration- and time-dependent decrease in cell proliferation (IC₅₀ = 27.5 ± 12.0 μg/mL after 96 h) and a reduced clonogenic survival (surviving fraction, SF = 0.56 ± 0.14; versus IONP_CO (SF = 1.07 ± 0.38)). Both IONP constructs were efficiently internalized and retained in the cells, and IONP_DOX efficiently delivered DOX resulting in increased cell death vs IONP_CO.

Tannic acid inhibits lipid metabolism and induce ROS in prostate cancer cells

Prostate cancer (PCa) cells exploit the aberrant lipid signaling and metabolism as their survival advantage. Also, intracellular storage lipids act as fuel for the PCa proliferation. However, few studies were available that addressed the topic of targeting lipid metabolism in PCa. Here, we assessed the tannic acid (TA) lipid-targeting ability and its capability to induce endoplasmic reticulum (ER) stress by reactive oxygen species (ROS) in PCa cells. TA exhibited dual effects by inhibiting lipogenic signaling and suppression of lipid metabolic pathways. The expression of proteins responsible for lipogenesis was down regulated. The membrane permeability and functionality of PCa were severely affected and caused nuclear disorganization during drug exposure. Finally, these consolidated events shifted the cell's survival balance towards apoptosis. These results suggest that TA distinctly interferes with the lipid signaling and metabolism of PCa cells.

Folic acid-conjugated magnetic mesoporous silica nanoparticles loaded with quercetin: a theranostic approach for cancer management

The development of drug carriers based on nanomaterials that can selectively carry chemotherapeutic agents to cancer cells has become a major focus in biomedical research. A novel pH-sensitive multifunctional envelope-type mesoporous silica nanoparticle (SBA-15) was fabricated for targeted drug delivery to human colorectal carcinoma cells (HCT-116). SBA-15 was functionalized with folic acid (FA), and the material was loaded with the water-insoluble flavonoid, quercetin (QN). Additionally, acid-labile magnetite Fe₃O₄ nanoparticles were embedded over the FA-functionalized QN-loaded monodisperse SBA-15 to prepare the highly orchestrated material FA-FE-SBA15QN. The in vitro and in vivo anti-carcinogenic efficacy of FA-FE-SBA15QN was carried out to explore the pH-sensitive QN release with putative mechanistic aspects. FA-FE-SBA15QN caused a marked tumor suppression, and triggered mitochondrial-dependent apoptosis through a redox-regulated cellular signaling system. Furthermore, FA-IO-SBA-15-QN initiated the c-Jun N-terminal Kinase (JNK)-guided H2AX phosphorylation, which relayed the downstream apoptotic signal to the phosphorylate tumor suppressor protein, p53. On the other hand, the selective inhibition of heat shock protein-27 (HSP-27) by FA-FE-SBA15QN augmented the apoptotic fate through JNK/H2AX/p53 axis. The in vitro and in vivo magnetic resonance imaging (MRI) studies have indicated the theranostic perspective of the composite. Thus, the result suggested that the newly synthesized FA-FE-SBA15QN could be used as a promising chemo theranostic material for the management of carcinoma.

pH-Sensitive quercetin/Fe₃O₄ NPs loaded functionalized mesoporous SBA-15 fabricated for targeted drug delivery to colorectal carcinoma cells with high anti-carcinogenic efficacy.

On-Chip Preparation of Amphiphilic Nanomicelles-in-Sodium Alginate Spheroids as a Novel Platform Against Triple-Negative Human Breast Cancer Cells: Fabrication, Study of Microfluidics Flow Hydrodynamics and Proof of Concept for Anticancer and Drug Delivery Applications

Spheroidal microparticles versatility as a drug carrier makes it a real workhorse in drug delivery applications. Despite of their long history, few research publications emphasize on how to improve their potential targeting ability, production rate, and dissolution characteristics. The current research presents an example of the combined state of the art of nano- and microparticles development technologies. Here in a novel on-chip, microfluidics approach is developed for encapsulating amphiphilic nanomicelles-in-sodium alginate spheroid. The designed nano-in-micro drug delivery system revealed a superior cytotoxicity against triple-negative human breast cancer cell line (MDA-MB-231), besides, a more sustained release of the drug. Hydrodynamics of the designed microchip was also investigated as a function of different flow rates with an insight on the dimensionless numbers; capillary number and Weber number throughout the microchannels. Our study confirmed the efficient encapsulation of nanomicelles within the alginate shell. The current microfluidics approach can be efficiently applied for uniform production of nano-in-microparticles with potential anticancer capability.

Magnetically Guided Self-Assembled Protein Micelles for Enhanced Delivery of Dasatinib to Human Triple-Negative Breast Cancer Cells

Magnetic nanocarriers are useful in targeted cancer therapy. Dasatinib (DAS)-loaded magnetic micelles were prepared for magnetically guided drug delivery. The magnetic nanoplatform is composed of hydrophobic oleic acid-coated magnetite (Fe₃O₄) core along with DAS encapsulated in amphiphilic zein-lactoferrin self-assembled polymeric micelles. Transmission electron microscope analysis manifested formation of these magnetic micelles with a mean diameter of about 100 nm. In addition, drug-loaded magnetic micelles displayed a saturation magnetization of about 10.01 emu.g^-1 with a superparamagnetic property. They also showed good in vitro serum stability and hemocompatibility accompanied with a sustained release of DAS in acidic pH. More importantly, they exhibited 1.35-fold increase in their in vitro cytotoxicity against triple-negative human breast cancer cell line (MDA-MB-231) using an external magnetic field compared to drug-loaded magnetic micelles in the absence of a magnetic field. Enhanced inhibition of p-c-Src protein expression level and in vitro cellular migration under the effect of magnetic field was noted owing to the dual-targeting strategy offered by the presence of a magnetic sensitive core, as well as the active targeting property of lactoferrin corona. Taken all together, these results suggest that DAS-loaded magnetic micelles possess a great potential for targeted therapy of breast cancer.

Targeting of EGFR, VEGFR2, and Akt by Engineered Dual Drug Encapsulated Mesoporous Silica-Gold Nanoclusters Sensitizes Tamoxifen-Resistant Breast Cancer

Tamoxifen administration enhanced overall disease-free survival and diminished mortality rates in cancer patients. However, patients with breast cancer often fail to respond for tamoxifen therapy due to the development of a drug-resistant phenotype. Functional analysis and molecular studies suggest that protein mutation and dysregulation of survival signaling molecules such as epidermal growth factor receptor, vascular endothelial growth factor receptor 2, and Akt contribute to tamoxifen resistance. Various strategies, including combinatorial therapies, show chemosensitize tamoxifen-resistant cancers. Based on chemotoxicity issues, researchers are actively investigating alternative therapeutic strategies. In the current study, we fabricate a mesoporous silica gold cluster nanodrug delivery system that displays exceptional tumor-targeting capability, thus promoting accretion of drug indices at the tumor site. We employ dual drugs, ZD6474, and epigallocatechin gallate (EGCG) that inhibit EGFR2, VEGFR2, and Akt signaling pathways since changes in these signaling pathways confer tamoxifen resistance in MCF 7 and T-47D cells. Mesoporous silica gold cluster nanodrug delivery of ZD6474 and EGCG sensitize tamoxifen-resistant cells to apoptosis. Western and immune-histochemical analyses confirmed the apoptotic inducing properties of the nanoformulation. Overall, results with these silica gold nanoclusters suggest that they may be a potent nanoformulation against chemoresistant cancers.

Micellear Gold Nanoparticles as Delivery Vehicles for Dual Tyrosine Kinase Inhibitor ZD6474 for Metastatic Breast Cancer Treatment

The therapeutic index of poorly water-soluble drugs is often hampered due to poor pharmacokinetics, reduced blood retention, and lack of effective drug concentrations in the tumor region. In order to overcome these issues, drugs are often delivered by use of delivery vehicles to provide an enhanced therapeutic index. Gold nanoparticles synthesized in micellar networks of amphiphilic block copolymer (AuNM) provide an efficient nanocarrier for tissue- and site-specific drug delivery owing to their low cytotoxicity and immunogenicity. AuNM is formed by exploiting the properties of both inorganic Au material and an amphiphilic polymer of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG). We further functionalized AuNM with the FDA-approved dual tyrosine kinase inhibitor ZD6474 and studied the physicochemical properties of the conjugate ZD6474-AuNM. Both AuNM and ZD6474-AuNM, with a diameter of ∼70 nm, were very stable at physiological pH. Conversely, at an acidic pH of 5.2, a slow sustained-release profile of ZD6474 was evident from AuNM, which could provide a method of facilitating release of the drug in an acidic tumor environment. In vitro, in triple-negative breast cancer cells, ZD6474-AuNM inhibited tumor cell proliferation, migration, and invasion and induced apoptosis. There was no detectable lysis of red blood cells observed when they were treated with AuNM and ZD6474-AuNM, confirming hemocompatibility. To reinforce the possibility of AuNM serving as a delivery vehicle, AuNM was conjugated with the IR680 dye for tracking, and this conjugate was systemically delivered in female nude mice bearing MDA-MB-231 human breast cancer xenografts. Fluorescence signal was retained in the tumor region in a temporal manner as compared to other organs, indicating passive retention of AuNM in the tumor locale. Moreover, delivery of ZD6474-AuNM in nude mice bearing MDA-MB-231 xenografts led to decreased tumor size as compared to the control group. The promising safety, targeting, and therapeutic results of systemic delivery of ZD6474 by AuNM provide an attractive alternative method for treating patients with metastatic breast cancer.