DEVELOPMENT AND PRECLINICAL ASSESSMENT OF NANOMATERIALS STABILIZED WITH AUTOLOGOUS SERUM PROTEINS FOR BREAST TUMOR MANAGEMENT

Abstract

Breast cancer has emerged as one of the most prevalent forms of cancer in 2020 according to world health organization report. Among four subtypes of breast cancer, triple negative breast cancer (TNBC) is the most challenging owing to loss of estrogen, progesterone and human epidermal growth factor receptors. These features limit the treatment modalities especially hormonal therapy and make the condition irresponsive to conventional therapy. Nanotechnology interventions have the potential to open new prospects for such challenging disease. In this thesis, we have assessed host specific nanomedicines which include drug nanocrystals and gold nanodendrites for monotherapy followed by their combinations towards management of breast tumor. First, we set to assess the safety and efficacy of drug nanocrystals based on the phytochemical curcumin (Cur-NanoSera) stabilized with host-specific serum proteins. Cur-NanoSera with high loading (∼63% w/w) showed superior in vitro anticancer efficiency compared to free drug with substantial hemocompatibility. The pre-adsorbed protein coating impeded further protein corona formation, even with repeated serum exposures. Acute and subacute toxicity evaluations post single and dual injections of C57BL/6 mice indicated that Cur-NanoSera showed no prominent inflammatory response or organ damage in the in-bred mice. Passive accumulation of Cur-NanoSera in tumor tissue significantly suppressed its growth in a syngeneic breast tumor model in addition to controlling tumor burden associated splenomegaly Next, we applied the host specific nanomaterial synthesis strategy to fabricate gold nanodendrites involving autologous serum proteins as both a template and stabilizer. The nanodendrites, also termed as ‘Plasmonic NanoSera’ (PNS), with size ∼150 nm, possess anisotropic dense branches with a broad extinction cross section across the visible-near Page | 1 infrared (I & II) regions. The PNS with a photothermal conversion efficiency of ∼58% under 808 nm laser irradiation demonstrated significant phototoxicity in cancer cells associated with elevated intracellular reactive oxygen species. The PNS did not cause acute toxicity with intravenous administration at 20 mg kg−1 dosage. Intra-tumoral injection of autologous mouse serum protein-derived PNS followed by 808 nm Laser irradiation generated a ∼78% higher localized temperature rise compared to a saline control in the 4T1 breast tumor model, thereby suppressing both the tumor growth and tumor burden-associated splenomegaly. This proof-of-concept study validates the preclinical safety and host-specific photothermal efficacy of PNS. Local recurrence post-surgery in early stage TNBC is a major challenge. In the final chapter, to control regrowth of residual tumor we have developed an autologous therapeutic hybrid fibrin glue. We incorporated drug nano/microcrystals and PNS into fibrin glue for intra-operative implantation in the tumor bed. We have optimized high drug loaded lapatinib-NanoSera (Lap-NS; ~ 66 % L.C) and Imiquimod-MicroSera (IMQ-MS; ~ 92 % L.C) and PNS with ~ 67 % photothermal conversion efficiency under 980 nm laser irradiation. The synthesis process used to fabricate this Nano-Micro-Sera (NMS) is sustainable and requires minimal resources devoid of synthetic surfactants, strong reducing agents and multi-step processes for their fabrication. While localized monotherapy with Lap-NS and PNS reduced tumor regrowth rate, their combination with IMQ amplified the effect of immunogenic cell death with high level of tumor infiltration by immune cells at the surgical site.