ABSTRACT
Mitochondrion has emerged as one of the unconventional targets in next-generation cancer therapy. Hence, small molecules targeting mitochondria in cancer cells have immense potential in the next-generation anticancer therapeutics. In this report, we have synthesized a library of hydrazide-hydrazone-based small molecules and identified a novel compound that induces mitochondrial outer membrane permeabilization by inhibiting antiapoptotic B-cell CLL/lymphoma 2 (Bcl-2) family proteins followed by sequestration of proapoptotic cytochrome c. The new small molecule triggered programmed cell death (early and late apoptosis) through cell cycle arrest in the G2/M phase and caspase-9/3 cleavage in HCT-116 colon cancer cells, confirmed by an array of fluorescence confocal microscopy, cell sorting, and immunoblotting analysis. Furthermore, cell viability studies have verified that the small molecule rendered toxicity to a panel of colon cancer cells (HCT-116, DLD-1, and SW-620), keeping healthy L929 fibroblast cells unharmed. The novel small molecule has the potential to form a new understudied class of mitochondria targeting anticancer agent.
ABSTRACT
RAS-RAF-MEK-ERK cascade in mitogen activated protein kinase (MAPK) signaling has been hijacked in colon cancer. However, the selective targeting of MAPK signaling components in colon cancer cells has remained a surmountable challenge. To address this, we have engineered hyaluronic acid cloaked 154 nm diameter oleic acid nanoparticles (HA-OA-NPs) comprising both an ERK inhibitor (AZD6244) and a DNA damaging drug (cisplatin). Dual drugs were slowly released from the HA-OA-NPs at an acidic pH (pH = 5.5) over 72 h. HCT-116 colon cancer cells engulfed these HA-OA-NPs by a CD44 receptor and clathrin-dependent endocytosis pathways followed by an accumulation into lysosomes over 6 h. These HA-OA-NPs inhibited the phosphorylation of extracellular signal-regulated kinases (ERK1 and ERK2) and damaged sub-cellular DNA to induce remarkable colon cancer cell (HCT-116 and DLD-1) death in contrast to a free drug cocktail at 24 h post incubation. Due to the biocompatibility and biodegradability of the nanoparticle components, the HA-OA-NPs could be brought into clinics as a platform for the synchronized inhibition of multiple targets for improved therapeutic efficacy in colon cancer patients.
ABSTRACT
Colon cancer has emerged as one of the most devastating diseases in the whole world. Mitogen-activated protein kinase (MAPK)-phosphatidylinsitol-3-kinase (PI3K) signaling hub has gained lots of attention due to its deregulation in colon cancer cells. However, selective targeting of oncogenic MAPK-PI3K hub in colon cancer has remained highly challenging, hence it has mostly been unexplored. To address this, we have engineered a hyaluronic acid layered lipid-based chimeric nanoparticle (HA-CNP) consisting of AZD6244 (MAPK inhibitor), PI103 (PI3K inhibitor), and cisplatin (DNA impairing drug) ratiometrically in a single particle. Electron microscopy (field emission scanning electron microscopy and atomic force microscopy) and dynamic light scattering were utilized to characterize the size, shape, morphology, and surface charge of the HA-CNPs. Fluorescent confocal laser scanning microscopy and flow cytometry analysis confirmed that HA-CNPs were taken up by HCT-116 colon cancer cells by merging of clathrin and CD44 receptor-mediated endocytosis along with macropinocytosis to home into acidic organelles (lysosomes) within 1 h. A gel electrophoresis study evidently established that HA-CNPs simultaneously inhibited MAPK-PI3K signaling hub with DNA damage in HCT-116 cells. These HA-CNPs stalled the cell cycle into G0/G1 phase, leading to induction of apoptosis (early and late) in colon cancer cells. Finally, these HA-CNPs exerted remarkable cytotoxicity in HCT-116 colon cancer cells at 24 h compared to that of the free triple drug cocktail as well as HA-coated dual drug-loaded nanoparticles without showing any cell death in healthy L929 fibroblast cells. These HA-coated CNPs have potential to be translated into clinics as a novel platform to perturb various oncogenic signaling hubs concomitantly toward next-generation targeted colon cancer therapy.