*3.2.1 Modified NPs: HA, FA, HER2 antibody for specific targeting*

Adding a ligand to the surface of NPs enhances drug delivery effectiveness to OC cells. Hyaluronic acid (HA) that is linked to CD44 which is a cell-surface glycoprotein and expresses specifically in tumor cells improves target delivery [30]. In the following, we mention an example that NPs modified by HA. Cisplatin-loaded polyarginine-HA NPs (CIS-pARG-HA NPs) were produced in this study, to overcome peritoneal carcinomatosis which generally diagnosis in the late stage of OC patients. In vitro studies on SKOV-3 cells showed reduced cell viability, by cooperation CD44 in cancer cells and an increase in cellular uptake. Also, the effectiveness of CIS-pARG-HA NPs improved, when these NPs were administered by pressurized intraperitoneal aerosol chemotherapy (PIPAC) due to the penetration into the peritoneal tumor [31].

Folate receptor α (FRα) is another marker that overexpresses in OC cells, so modifying NPs surface by folic acid (FA) is another mechanism in specific target delivery. Using FA due to low immunogenic, inexpensive and stable properties, is more welcomed. Below we gather two examples in the level of in vitro and in vivo, to evaluating target delivery by FA ligand which binds to NPs [30].

PTX loaded PLGA NPs modified by FA for oncotherapy. For comparison, modified NPs with non-modified NPs, were used to treat SKOV3 cells. FA improved the effect of NPs and rise up the cytotoxicity by increasing cellular uptake, and disrupt in cell division and apoptosis process [32]. In another study, Nanoemulsion (NE) as a delivery system was used to loaded docetaxel (DTX) and FA for treating OC. Cell treatment by this nanocarrier enhanced cytotoxicity due to the DTX, while treatment transgenic mouse model of ovarian carcinoma induced inhibition in tumor growth and volume [33].

The overexpression of the HER2 receptor is another specific marker that contributes to OC. CIS and trastuzumab and HER2-targeted antibody conjugated with poly(lactic-co-glycolic) NPs target HER2 receptor. CIS via impressing on DNA conformational and by a dose-dependent manner cause cytotoxicity and apoptosis in SKOV3 cells. The effectiveness of this delivery system after modifying by trastuzumab and chitosan increased in both in vitro and in vivo experiments [34]. Cell viability in HER-2-overexpressing cell line can also decrement by treating them with poly(butylene adipate-co-butylene terephthalate) (Ecoflex®) NPs by adding an aptamer engineer to improving the efficacy and reducing the side effects of DTX. For evaluating antitumor activity and biodistribution, tumor-bearing B6 athymic mice received NPs intravenously and significant results were obtained [35].

### *3.2.2 Control drug released from NPs: pH and GSH sensitive NPs*

pH-sensitive NPs are widely utilized for drug delivery. Drugs released from NPs are controlled by various factors like pH. A2780 as a CIS sensitive and A2780DDP as a CIS resistant OC cells treated by pH-sensitive Fe3O4 NPs encapsulating CIS for reducing its side effect and drug resistance. NPs@CIS cause more internalization and in the following more drug accumulation in OC cells. In both cell lines, cytotoxicity and apoptosis increased because of the drug entry into the cell nucleus. The existence of an external magnetic field for in vivo experiments enhanced the antitumor efficacy and inhibition toxicity in normal tissues [36].

In another study, Tariquidar (TQR) and DOX loaded a pH-sensitive liposome formulation (pHSL) (pHSL/TQR/DOX) was prepared to overcome multidrug

*Ovarian Cancer - Updates in Tumour Biology and Therapeutics*

pre-clinical application of NPs for OC oncotherapy.

**3.2 Drug delivery**

targeted NPs to OC cells.

usual results that have been obtained.

In gen delivery NPs carrying nucleic acids containing microRNA (miRNA), short hairpin RNA (shRNA), antisense oligonucleotides (AONS) and small interfering RNA (siRNA), with the silencing or downregulation purpose of genes or proteins which related to drug-resistant, angiogenesis or metastasis are used for improving oncotherapy and resolve the conventional therapy limitation [28]. We summarize nanotechnology based therapeutics in **Figure 2**. Here, we review the

In this section, we gathered some experiments that used different types of NPs for drug delivery to overcome the common problem in the treatment of OC as a lethal gynecological cancer worldwide, which almost diagnosis in late stages with the high rate of drug resistance for diagnosis and treatment. The advantages encourage researchers to utilized NPs consist of: NPs are used for drug delivery that lead to more effective in OC treatment. Also, reduce side effects due to specificity

SKOV3 and A2780 are the most usable cells for in vitro experiments that are treated by different kinds of drug loaded NPs. NPs are modified by several ligands such as hyaluronic acid, folic acid and HER2-targeted ligand for enhancing target delivery. GSH (Glutathione)-sensitive and pH-sensitive are other properties of these NPs that improve their effectiveness. As results showed the stability and biodistribution of these NPs that encapsulate drugs are very impressive. Increasing cellular uptake and cytotoxicity by inducing apoptosis or necrosis for in vitro experiments, and tumor growth and volume inhibition in the level of in vivo are the

The most barrier to entrance NPs into the cells through endosomes is an endosomal escape. Transferrin (Tf) and octaarginine (R8) play role in endosomal scape and specific delivery respectively. IAR-CPP R8 and Tf linked to the surface of PEGylated liposomes, which encapsulated doxorubicin (DOX) (DOXIL®) for

*Drugs or RNA interference (miRNA/siRNA/shRNA) loaded to lipid-based or polymeric nanoparticle as common nanocarriers are designed for delivery to OC cells in order to oncotherapy. Surface of these nanoparticles modified by different ligands such as hyaluronic acid (HA), folic acid (FA), Polyethylene glycol* 

*(PEG) and Polyethylenimine (PEI) for enhancing efficiency.*

**178**

**Figure 2.**

resistance. pHSL made from CHEMS (cholesteryl hemisuccinate), DOPE (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine) and PEGylated lipid which DOX and TQR placed in the water and lipid phases respectively and this nano vehicle prolong circulation. Cytotoxicity was investigated by treatment OVCAR8/ADR cells with pHSL/TQR/DOX (**Figure 3**) [37].

Combination of FA ligand for specific target delivery and pH-sensitive NPs proposed phenomenal nanocarrier for ovarian oncotherapy. Magnetic NPs (MNPs) and MTX through carboxylic acid groups and amino groups of chitosan linked to chitosan copolymer and prepared thermos and pH-sensitive MTX-CSC@MNPs that conjugate with erlotinib (ETB) for target delivery. Since MTX and FA are similar structurally this nano vehicle absorbed with folate receptor on OVCAR-3 cells and prompt cytotoxicity and apoptosis induced by ETB [38]. Moreover, pH-sensitive Glucose/gluconic acid-coated magnetic NPs that linked to FA in the surface, enclosed DOX. External magnetic fields improve drug release in tumor tissue. For evaluating cell viability A2780, OVCAR3 and SKOV3 cells treated by these NPs and results demonstrated an increase in internalization and cytotoxicity. Analyzing the tissues of the SKOV3-Luc cell-xenografted nude mouse model showed accumulation of the drug in tumor cells more than other parts of the body that it causes to block the tumor growth [39].

Drug released is also controlled by intracellular GSH concentration. GSH sensitive polymersomal DOX nano vehicle that modified by GE11 peptide (GE11- PS-Dox) is one of these NPs produced for treatment SKOV3 cells with a high level of epidermal growth factor receptor (EGFR). After drug delivery to tumor tissue and cancer cells, DOX enters the cell nucleus and inhibits tumor progress and increases cytotoxicity. The efficiency of this treatment is more than Lipo-Dox or Dox alone (**Figure 4**) [40].
