Enhancing PDT efficacy in NMIBC: Efflux inhibitor mediated improvement of PpIX levels and efficacy of the combination of PpIX-PDT and SO-cleavable prodrugs.

Protoporphyrin IX (PpIX)-based photodynamic therapy (PDT) has shown limited efficacy in nonmuscle-invasive bladder cancer (NMIBC). To improve PDT efficacy, we developed singlet oxygen-cleavable prodrugs. These prodrugs, when combined with PpIX-PDT, induce cancer cell death through both PDT and drug release mechanisms. Inhibition of PpIX efflux was reported to be an effective strategy to improve PpIX-PDT in certain cancer cells. Our main goal was to investigate whether adding an efflux inhibitor to the combination of PpIX and prodrugs can improve the PpIX levels in bladder cancer cells and the release of active drugs, thus improving the overall efficacy of the treatment. We treated bladder cancer cell lines with lapatinib and evaluated intracellular PpIX fluorescence, finding significantly increased accumulation. Combining lapatinib with prodrugs led to significantly reduced cell viability compared to prodrugs or PpIX-PDT alone. The effect of lapatinib depended on the expression level of the efflux pump in bladder cancer cells. Interestingly, lapatinib increased paclitaxel (PTX) prodrug uptake by threefold compared to prodrug alone. Adding an efflux inhibitor (e.g., lapatinib) into bladder instillation solutions could be a straightforward and effective strategy for NMIBC treatment, particularly in tumors expressing efflux pumps, with the potential for clinical translation.

Mitochondrial targeting improves the selectivity of singlet-oxygen cleavable prodrugs in NMIBC treatment.

Mitochondria play an essential role in cancer treatment by providing apoptotic signals. Hexyl aminolevulinate, an FDA-approved diagnosis for non-muscle invasive bladder cancer, induces the production of protoporphyrin IX (PpIX) preferentially by mitochondria in cancer cells. Photosensitizer PpIX upon illumination can release active chemotherapy drugs from singlet oxygen-activatable prodrugs. Prodrugs placed close enough to PpIX formed in mitochondria can improve the antitumor efficiency of PpIX-PDT. The preferred uptake of prodrugs by cancer cells and tumors can further enhance the selective damage of cancer cells over non-cancer cells and surrounding normal tissues. Mitochondriotropic prodrugs of anticancer drugs, such as paclitaxel and SN-38, were synthesized using rhodamine, a mitochondrial-targeting moiety. In vitro, the mitochondrial targeting helped achieve preferential cellular uptake in cancer cells. In RT112 cells (human bladder cancer cells), intracellular prodrug concentrations were 2-3 times higher than the intracellular prodrug concentrations in BdEC cells (human bladder epithelial cells), after 2 h incubation. In an orthotopic rat bladder tumor model, mitochondria-targeted prodrugs achieved as much as 34 times higher prodrug diffusion in the tumor area compared to the nontumor bladder area. Overall, mitochondria targeting made prodrugs more effective in targeting cancer cells and tumors over non-tumor areas, thereby reducing nonspecific toxicity.

Comparison of red and green light for treating non-muscle invasive bladder cancer in rats using singlet oxygen-cleavable prodrugs with PPIX-PDT.

It has been 30 years since Photofrin-PDT was approved for the treatment of bladder cancer in Canada. However, Photofrin-PDT failed to gain popularity due to bladder complications. The PDT with red light and IV-administered Photofrin could permanently damage the bladder muscle. We have been developing a new combination strategy of PpIX-PDT with singlet oxygen-cleavable prodrugs for NMIBC with minimal side effects, avoiding damage to the bladder muscle layer. PpIX can be excited by either green (532 nm) or red (635 nm) light. Red light could be more efficacious in vivo due to its deeper tissue penetration than green light. Since HAL preferentially produces PpIX in tumors, we hypothesized that illuminating PpIX with red light might spare the muscle layer. PpIX-PDT was used to compare green and red laser efficacy in vitro and in vivo. The IC50 of in vitro PpIX-PDT was 18 mW/cm2 with the red laser and 22 mW/cm2 with the green laser. The in vivo efficacy of the red laser with 50, 75, and 100 mW total dose was similar to the same dose of green laser in reducing tumor volume. Combining PpIX-PDT with prodrugs methyl-linked mitomycin C (Mt-L-MMC) and rhodamine-linked SN-38 (Rh-L-SN-38) significantly improved efficacy (tumor volume comparison). PpIX-PDT or PpIX-PDT + prodrug combination did not cause muscle damage in histological analysis. Overall, a combination of PpIX-PDT and prodrug with 635 nm laser is promising for non-muscle invasive bladder cancer treatment.

Ameliorative anticancer effect of dendrimeric peptide modified liposomes of letrozole: In vitro and in vivo performance evaluations.

Letrozole (LTZ) loaded dendrimeric nano-liposomes were prepared for targeted delivery to breast cancer cells. Surface modification with cationic peptide dendrimers (PDs) and a cancer specific ligand, transferrin (Tf), was attempted. Arginine-terminated PD (D-1) and Arginine-terminated, lipidated PD (D-2) were synthesized using Solid Phase Peptide Synthesis, purified by preparative HPLC and characterized using 1HNMR, MS and DSC analyses. Surface modification of drug loaded liposomes with Tf and/or PD was carried out. Formulations were characterized using FTIR, DSC, 1HNMR, XRD and TEM. Tf-conjugated LTZ liposomes (LTf) and Tf/D-2-conjugated LTZ liposomes (LTfD-2) showed greater cytotoxic potential (IC50 = 95.03 µg/mL and 23.75 µg/mL respectively) with enhanced cellular uptake in MCF7 cells compared to plain LTZ. Blocking studies of Tf (Tf-receptor mediated internalization) revealed decreased uptake of LTf and LTfD-2 confirming the role of Tf in uptake of Tf-conjugated liposomes. Intravenous treatment with LTfD-2 caused highest reduction in tumor volumes of female BALB/c-nude mice (145 mm3) compared to plain LTZ (605 mm3) and unconjugated LTZ liposomes (LP) (300 mm3). In vivo biodistribution studies revealed higher fluorescence in tumor tissue and liver of LTfD-2 treated mice than LTf or LP treatment. Immunohistochemical studies revealed greater apoptotic potential of LTfD-2 as indicated by TUNEL assay and ROS detection assay. The study reveals the superior therapeutic efficacy of the developed LTZ liposomal nanocarriers using PDs to enhance the transfection efficiency in addition to modifying the surface characteristics by attaching a targeting ligand for active drug targeting to breast cancer cells.

Overcoming drug resistance with a docetaxel and disulfiram loaded pH-sensitive nanoparticle.

Previous studies have demonstrated that breast cancer cells deploy a myriad array of strategies to thwart the activity of anticancer drugs like docetaxel (DTX), including acquired drug resistance due to overexpression of drug-efflux pumps like P-glycoprotein (P-gp) and innate drug resistance by cancer stem cells (CSCs). As disulfiram (DSF) can inhibit both P-gp and CSCs, we hypothesized that co-treatment of DTX and DSF could sensitize the drug-resistant breast cancer cells. To deliver a fixed dose ratio of DTX and DSF targeted to the tumor, a tumor extracellular pH-responsive nanoparticle (NP) was developed using a histidine-conjugated star-shaped PLGA with TPGS surface decoration ([DD]NpH-T). By releasing the encapsulated drugs in the tumor microenvironment, pH-sensitive NPs can overcome the tumor stroma-based resistance against nanomedicines. In in-vitro studies, [DD]NpH-T exhibited increased drug release at pH 6.8, improved penetration in a 3D tumor spheroid, reduced serum protein adsorption, and enhanced cytotoxic efficacy against both innate and acquired DTX-resistant breast cancer cells. In in-vivo studies, a significant increase in plasma AUC and tumor drug delivery was observed with [DD]NpH-T, which resulted in an enhanced in-vivo anti-tumor efficacy against a mouse orthotopic breast cancer, with a significantly increased intratumoral ROS and apoptosis, while decreasing P-gp expression and prevention of lung metastasis. Altogether, the current study demonstrated that the DTX and DSF combination could effectively target multiple drug-resistance pathways in-vitro, and the in-vivo delivery of this drug combination using TPGS-decorated pH-sensitive NPs could increase tumor accumulation, resulting in improved anti-tumor efficacy.

Human serum albumin-poly(Lactide)-conjugated self-assembly NPs for targeted docetaxel delivery and improved therapeutic efficacy in oral cancer.

Oral cancer is one of the most prevalent malignancies worldwide. Here, to prepare a biocompatible tumor-targeted nanoformulation capable of efficient loading of the hydrophobic drug, DTX, human serum albumin was conjugated to poly(lactide) at different HSA: PLA ratios (1:1, 2, 3). The HSA-(PLA)1-3 conjugates were physicochemically characterized by UV, IR, NMR, GPC, pyrene incorporation, and surface tension analysis. Next, the DTX-loaded DTX@HSA-(PLA)1-3 NPs were prepared by the desolvation-self-assembly technique, which was further optimized by DOE. The NPs were characterized by DLS, SEM, DSC, XRD, CD spectroscopy, SDS-PAGE, drug entrapment and loading efficiencies, kinetic stability, drug release, and hemolysis assays. Murine and human oral cancer cell lines, MOC2 and FaDu, were used in monolayers/multicellular spheroids to assess cellular uptake, the extent of cell viability, and apoptosis induction following NPs treatment. The DTX@HSA-(PLA)1-3 NPs were ~ 149-212 nm size range, drug entrapment, ~75-96 %, and loading efficiency, ~21-27 %. The selected DTX@HSA-(PLA)2 NPs showed time-dependent improved targetability towards cancer cells than HSA NPs, indicating the benefit of HSA polymerization in NPs internalization. A time-dependent decrease in cell viability was observed for both the cell lines with IC50 values, 7.12 ± 1.84 and 6.38 ± 1.63 µg/mL, for FaDu and MOC2 cell lines, respectively (48 h post-treatment). The DTX@ HSA-(PLA)2 NPs treatment induced higher apoptotic marker expressions, cell-cycle arrest in the G2/M-phase, DNA damage, and mitochondrial depolarization than free DTX and DTX@HSA NPs. Further, DTX@HSA-(PLA)2 NPs (iv) showed significantly reduced plasma clearance (p < 0.05) and volume of distribution (Vd) than DTX and DTX@HSA NPs. Therefore, the developed polyprotein NPs offer superior therapeutic effect due to their stable drug incorporation, improved cell internalization, and long circulation, revealing their potential as an effective nanomedicine for oral cancer treatment.

Oleanolic acid-conjugated human serum albumin nanoparticles encapsulating doxorubicin as synergistic combination chemotherapy in oropharyngeal carcinoma and melanoma.

Combination chemotherapy produces a superior therapeutic response than monotherapy in cancer. Human serum albumin and a naturally occurring cancer prophylactic/anticancer triterpenoid, oleanolic acid, were conjugated to form self-assembled nanoparticles that entrapped doxorubicin. Dox@HSA-OA NPs were physicochemically characterized for particle size, zeta potential, drug loading, entrapment efficiency, stability, release, and hemocompatibility. The Dox@HSA-OA NPs (particle size. âˆ¼ 140 nm) showed commendable loading (14.6 %), entrapment (59.01%) of Dox. The in vitro cell uptake study using human oral squamous carcinoma (FaDu-HTB-43) and murine melanoma (B16F10) cells indicated a higher cellular association of Dox@HSA-OA NPs than free Dox. The lowest IC50 of Dox@HSA-OA NPs than Dox against both the cell lines at various time points proved the Dox/HSA-OA-mediated combination chemotherapeutic effect. Dox@HSA-OA NPs demonstrated higher apoptosis and cell cycle arrest (G2/M phase). The Dox@HSA-OA NPs-mediated Dox penetration, cell death/shrinkage were significant in FaDu-HTB-43 spheroids. Dox@HSA-OA NPs showed a better pharmacokinetic profile with increased t1/2 and Cmax than Dox. The in vivo experiment using B16F10 tumor-bearing mice showed tumor regression, DNA damage, oxidative stress, and apoptosis-induction via the intrinsic pathway to a greater extent following Dox@HSA-OA NPs treatment than Dox. Therefore, the Dox@HSA-OA NPs-mediated combination therapy could be a powerful treatment strategy for solid tumors.