Etoposide Loaded SPION‐PNIPAM Nanoparticles Improve the in vitro Therapeutic Outcome on Metastatic Prostate Cancer Cells via Enhanced Apoptosis

Abstract

Prostate cancer is among the leading causes of death worldwide because its metastatic form is a deadly disease. Therefore, the development of new chemotherapeutics is of immense importance. Nanoparticle technology seems to provide diverse options in this regard. Therefore, poly(N-isopropylacrylamide) (PNIPAM) coated superparamagnetic iron oxide nanoparticles (SPION) loaded with Etoposide were prepared in small sizes (57 nm) and with 3.5 % drug content to improve the efficiency of Etoposide in prostate cancer therapy. Sustained release of the drug was achieved, which found to be sensitive to low pH and high temperature. The anti-growth activity of SPION-PNIPAM-Etoposide formulation against metastatic prostate cancer cells (PC-3, LNCaP) were investigated by SRB assay, then, confirmed by ATP assay. Mode of cell death was evaluated by using flow cytometry analyses. A significant improvement of nanoformulated drug was observed at 5-10 μg/ml doses of the drug in both cell lines. More importantly, this formulation enhanced the cytotoxic effect of Etoposide on PC-3 cells, which is considered more resistant to Etoposide than LNCaP and reduced the IC 50 value by 55 % reaching to 4.5 μg drug/ml, which is a very significant improvement in the literature. It was clearly shown that nanoformulated drug provided about 3-fold increases in caspase-dependent early apoptotic cells in PC-3 cells. The novel formulation seems to successfully cause cell death of especially PC-3 metastatic prostate cancer cells. It should therefore be taken into consideration for further animal studies as a novel potent anticancer agent.

Combinatory Delivery of Etoposide and siCD47 in a Lipid Polymer Hybrid Delays Lung Tumor Growth in an Experimental Melanoma Lung Metastatic Model

“…The improvement of potential Eto cytotoxicity after encapsulation in nanoparticles was previously reported in different types of nanocarriers as liposomes, [ 52 ] PLGA nanoparticles, [ 53 ] albumin nanoparticles, [ 54 ] and poly ( N ‐isopropylacrylamide) coated superparamagnetic iron oxide nanoparticles. [ 55 ] The ability of nanoparticles to improve cytotoxicity is not exclusive for Eto but was also reported for several other anticancer drugs as paclitaxel, [ 56 ] cisplatin, [ 57 ] Epirubicin, [ 58 ] and doxorubicin. [ 59 ] This could be attributed to the fact that about 50 % of the anticancer drugs, including etoposide, are substrates to P glycoprotein (P‐gp) mediated efflux.…”

Poly(N-isopropylacrylamide)-Based Hydrogels for Biomedical Applications: A Review of the State-of-the-Art

“…Accordingly, systems such as, PNIPAM@ magnetic NPs (Fe 3 O 4 )/5-fluorouracil (5FU) and oxaliplatin (OXA)- acrylic acid (AA), 3-butenoic acid (3BA) or allylamine (AL) (pNIPAM@ Fe 3 O 4 /5FU/OXA-AA, 3BA, AL) [ 181 ], doxorubicin(DOX)-gold nanorods (GNRs)-PNIPAM@poly (d, l-lactide)-poly (ethylene glycol) (PLA-PEG) (DAPP)micelles (DOX-GNRs-PNIPAM@PEG-PLA,DAPP) [ 182 ], vancomycin (VANCO)/SF-Na Alg NPs/PNIPAM@epidermal growth factor (EGF) (VANCO/SF-Na Alg NPs/PNIPAM@EGF) [ 183 ], PNIPAM- superparamagnetic iron oxide nanoparticles (SPION)- etoposide (SPION-PNIPAM-Etoposide) [ 184 ], NaALG-g-P(NIPAM 80 - co -NtBAM 20 )/Dulbecco’s modified Eagle’s medium (DMEM) (NaALG-g-P(NIPAM 80 - co -NtBAM 20 )/DMEM) [ 185 ] and many more have been designed by researchers in order to intensify the use of PNIPAM polymer in the field of drug delivery [ 186 , 187 ]. Table 1 depicts the latest investigations of PNIPAM-based hydrogels in drug delivery.…”

The improved killing of both androgen-dependent and independent prostate cancer cells by etoposide loaded SPIONs coupled with NIR irradiation

“…The PNIPAM-SPION/Eto combination improved the cytotoxicity of free Eto on LNCaP only at high doses, but less-sensitive PC-3 cells were well treated with the SPION/Eto, which reduced the IC 50 value from >10 µg Eto per mL (for free drug) to 4.5 µg Eto per mL. 11 So, the delivery of Eto with nanoparticles seems to improve Eto-therapy on androgen-independent prostate cancers as well. 11,14 There are examples of Eto loaded polymeric nanoparticles as well.…”

“…10 Alternatively, several groups exploited the possibility of loading Eto to nanoparticles. [11][12][13] Ali et al encapsulated Eto into gold/polyvinylalcohol/hydroxypropyl methyl cellulose nanoparticles and reported reduced cytotoxicity on healthy cell lines (BEAS-2 versus NHI-H69). 8 Saroj et al loaded Eto to folic acid (FA) functionalized mesoporous silica nanoparticles (MSNs) and observed slower plasma elimination as compared to free Eto and improved apoptotic cell death of both androgen-independent PC-3 and androgendependent LNCaP cells.…”

“…11 So, the delivery of Eto with nanoparticles seems to improve Eto-therapy on androgen-independent prostate cancers as well. 11,14 There are examples of Eto loaded polymeric nanoparticles as well. 12,15 Recently, Alfei et al loaded Eto to a biodegradable polyester dendrimer for the sustained release of the drug and in turn, achieved 30% more toxicity on human neuroblastoma (NB) cells than free Eto.…”