delivery of therapeutics in patients(29, 30), is usually challenging in preclinical designs and have been successful only for sub-cutaneous or intraperitoneal delivery of drugs in mice(31, 32)

delivery of therapeutics in patients(29, 30), is usually challenging in preclinical designs and have been successful only for sub-cutaneous or intraperitoneal delivery of drugs in mice(31, 32). of tumor cells within 12 hours after intraperitoneal (IP) injection of CMV GFP c-CPE-NP in mice harboring chemotherapy-resistant ovarian cancer xenografts. Finally, multiple IP injections of p16 DT-A c-CPE-NP resulted in a substantial inhibition of tumor development compared Rabbit Polyclonal to CSTL1 to control NP in chemotherapy-resistant tumor-bearing mice (p=0. 041). p16 DT-A c-CPE-NP may signify a story dual-targeting restorative approach pertaining to the selective delivery of gene therapy to chemotherapy-resistant ovarian malignancy cells. Keywords: Ovarian Malignancy, Clostridium Perfringens Enterotoxin(CPE), PLGA nanoparticles, Claudin-3 and -4, Chemotherapy resistance, Gene therapy == Advantages == Ovarian cancer continues to be the most lethal gynecologic malignancy in the USA(1). Despite the preliminary positive medical response to surgical G-479 procedure and chemotherapy, the majority of ovarian cancer individuals eventually becomes resistant to chemotherapy and develop recurrent disease that is lethal in most cases(2, 3). Hence, there is an extreme need to develop more effective restorative strategies to focus on chemotherapy-resistant ovarian cancer. The usage of targeted treatments represents a perfect approach to improve antitumor efficacy while minimizing treatment-related toxicity(4). With the aim of identifying ovarian cancer-specific objectives, our group as well as G-479 others have evaluated the genetic alterations found in ovarian tumors(57). Data have got consistently identified that the genes encoding pertaining to claudin-3 and claudin-4 are highly differentially indicated in ovarian cancer cells compared to typical ovarian cells. More importantly, we showed higher expression of claudin-4 in chemotherapy-resistant compared to matched chemotherapy-nave tumors and in the sub-population of CD44-positive ovarian malignancy stem cells compared to CD44-negative counterparts(8, 9). Claudin-3/-4 would be the high affinity receptors forClostridium PerfringensEnterotoxin (CPE), a polypeptide of 319 amino acids associated with C. perfringenstype-A food poisoning(10). Interestingly, although the full-length CPE is highly toxic when injected intravenously in animals, the carboxi-terminal fragment (i. e., the C-terminal 30aa) of CPE, is devoid of any toxicity while sufficient intended for binding to its receptors(11). Accordingly, several strategies have been developed that used the c-CPE as a tumor-specific carrier for diagnostic and therapeutic agents(12, 13). Importantly, recent data from our research group showed that c-CPE conjugated to the NearInfraRed-Dye CW800 is highly effective in identifying microscopic/metastatic ovarian tumor in the abdomen of G-479 mice harboring ovarian cancer xenografts(12, 14). Taken together theses evidences suggest that therapeutic systems that funnel the focusing on specificity of c-CPE may potentially be highly effective for the treatment of this disease. Gene therapy represents a good alternative treatment modality in the management of ovarian cancer. Consistent with this view, a recent work by Huang et al. demonstrated that biodegradable poly(-amino-ester) polymers may efficiently deliver transcriptionally targetedDiphteria Toxinsubunit A DNA (i. e., the catalytic domain name of the full lengthDiphteria Toxin: DT-A) to ovarian cancer cellsin-vivo, resulting in strong inhibition of tumor growth(15). This study demonstrated that ovarian cancer cells are sensitive to DT-A exposure and that a DT-A-based gene therapy is an approach which should be considered intended for the treatment of this disease. Poly-(D. L-lactic-co-glycolic)-acid-(PLGA)-nanoparticles-(NP) are well characterized, non-toxic and effective systems intended for the delivery of DNA to cancer cells(16). A recent study by our group evaluated the DNA delivery properties of a novel non-viral nanoparticle system containing a blend of G-479 PLGA and poly-(beta-amino)-ester (PBAE)(17). Data showed that the addition of PBAE to PLGA generated cationic nanoparticles that were efficient in transfecting tumor cellsin-vitro. More importantly, results exposed increased plasmid loading capacity and increased transfection efficiency after conjugation of nanoparticles with cell-penetrating peptides (i. e., mTAT, bPrPp and MPG) via a PEGylated phospholipid linker (DSPE-PEG2000)(17). Here we synthesized and characterized PLGA/PBAE NPs conjugated to the c-CPE peptide and tested their efficiency in delivering suicide gene therapy to chemotherapy-resistant ovarian cancer cells bothin-vitroandin-vivo. As a therapeutic payload we encapsulated a plasmid into the NPs which encodes intended for the DT-A under the transcriptional control of the p16 promoter. The cyclin-dependent kinase inhibitor p16 is encoded by theCDKN2Agene. P16 plays a pivotal role in the regulation of the transit through the G1 phase from the cell cycle by inhibiting the activity of CDK4 and CDK6. The binding of p16 to CDK4/6 prevents their relationship with cyclin D and the subsequent phosphorylation of substrates that are essential for the G1-S transition(18). Because of its function, p16 is considered a tumor suppressor gene. Deletions and mutations of p16 are commonly detected in many neoplasms, including.