Antitumor and antimetastatic effects of pemetrexed-loaded targeted nanoparticles in B16 bearing mice

EGFR-targeted pemetrexed therapy of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare malignancy with poor prognosis, for which chemotherapy with pemetrexed (PEM) is among the few clinical treatments. PEM suffers, however, fast clearance, moderate drug exposure, and dose-limiting toxicities. Here, we report on epidermal growth factor receptor (EGFR)-targeted disulfide-crosslinked biodegradable chimaeric polymersomes (EGFR-CPs) to firmly load PEM and boost chemotherapy of MPM. EGFR-CPs encapsulating 8.7-16.4 wt.% PEM (EGFR-CPs-PEM) showed diameters of 62-65 nm and reduction-responsive drug release property. EGFR-CPs-PEM was more efficiently taken up by EGFR-overexpressed MSTO-211H cells, inducing about 4.7-fold enhanced anticancer activity compared with non-targeted CPs-PEM control. Intriguingly, the in vivo experiments in MSTO-211H xenograft mouse model revealed that EGFR-CPs-PEM brought about superior tumor deposition and penetration to CPs-PEM, and significantly more potent tumor repression than CPs-PEM and free PEM. This polymersome-enabled EGFR-targeted delivery of PEM offers an appealing therapeutic strategy for MPM.

Development of a Pemetrexed/Folic Acid Nanoformulation: Synthesis, Characterization, and Efficacy in a Murine Colorectal Cancer Model

The folate analogue pemetrexed (PEM) is an approved therapeutic for non-small cell lung cancer and malignant pleural mesothelioma with the potential for broader application in combination therapies. Here, we report the development of a nanoformulation of PEM and its efficacy against the CT26 murine colorectal cancer cell line in vitro and in vivo. Utilizing layer-by-layer deposition, we integrate PEM, along with folic acid (FA), onto a fluorescent polystyrene nanoparticle (NP) substrate. The final nanoformulation (PEM/FA-NP) has a size of ∼40 nm and a zeta potential of approximately -20 mV. Cell uptake studies indicated increased uptake in vitro for the PEM/FA-NP compared to the uncoated NP, likely due to the presence of PEM and FA. Viability studies were performed to determine the potency of the PEM/FA-NP formulation against CT26 cells. Syngeneic CT26 tumors in BALB/c mice showed reduced growth when treated once daily (2.1 mg/kg PEM) for 3 days with PEM/FA-NP versus the vehicle (uncoated) control, with no observable signs of systemic toxicity associated with the nanoformulation. Although the current study size is limited (n = 4 animals for each group), the overall performance and biocompatibility of the PEM/FA-NP observed suggest that further optimization and larger-scale studies may be warranted for this novel formulation.

Development of dual-drug-loaded stealth nanocarriers for targeted and synergistic anti-lung cancer efficacy

Combination chemotherapy is widely exploited for suppressing drug resistance and achieving synergistic anticancer efficacy in the clinic. In this paper, the nanostructured targeting methotrexate (MTX) plus pemetrexed (PMX) chitosan nanoparticles (CNPs) were developed by modifying methoxy polye (thylene glycol) (mPEG), in which PEGylation CNPs was used as stealth nanocarriers (PCNPs) and MTX was employed as a targeting ligand and chemotherapeutic agent as well. Studies were undertaken on human lung adenocarcinoma epithelial (A549) and Lewis lung carcinoma (LLC) cell lines, revealing the anti-tumor efficacy of nanoparticle drug delivery system. The co-delivery nanoparticles (MTX-PMX-PCNPs) had well-dispersed with sustained release behavior. Cell counting kit-8 (CCK8) has been used to measure A549 cell viability and the research showed that MTX-PMX-PCNPs were much more effective than free drugs when it came to the inhibition of growth and proliferation. Cell cycle assay by flow cytometry manifested that the MTX-PMX-PCNPs exhibited stronger intracellular taken up ability than free drugs at the same concentration. In vivo anticancer effect results indicated that MTX-PMX-PCNPs exhibited a significantly prolong blood circulation, more tumoral location accumulation, and resulted in a robust synergistic anticancer efficacy in lung cancer in mice. The results clearly demonstrated that such unique synergistic anticancer efficacy of co-delivery of MTX and PMX via stealth nanocarriers, providing a prospective strategy for lung cancer treatment.

Lung cancer specific and reduction-responsive chimaeric polymersomes for highly efficient loading of pemetrexed and targeted suppression of lung tumor in vivo

Lung cancer is one of the worldwide leading and fast-growing malignancies. Pemetrexed disodium (PEM, Alimta®), a small hydrophilic drug, is currently used for treating lung cancer patients. However, PEM suffers from issues like fast elimination, low bioavailability, poor tumor cell selectivity and penetration. Here, we report on lung cancer specific CSNIDARAC (CC₉) peptide-functionalized reduction-responsive chimaeric polymersomes (CC₉-RCPs) for efficient encapsulation and targeted delivery of PEM to H460 human lung cancer cells in vitro and in vivo. PEM-loaded CC₉-RCPs (PEM-CC₉-RCPs) was obtained from co-self-assembly of poly(ethylene glycol)-b-poly(trimethylene carbonate-co-dithiolane trimethylene carbonate)-b-polyethylenimine (PEG-P(TMC-DTC)-PEI) and CC₉-functionalized PEG-P(TMC-DTC) in the presence of PEM followed by self-crosslinking. PEM-CC₉-RCPs displayed an optimal CC₉ density of 9.0% in targeting H460 cells, a high PEM loading content of 14.2 wt%, a small hydrodynamic size of ca. 60 nm and glutathione-triggered PEM release. MTT assays showed that PEM-CC₉-RCPs was 2.6- and 10- fold more potent to H460 cells than the non-targeting PEM-RCPs and free PEM controls, respectively. Interestingly, PEM-CC₉-RCPs exhibited 22-fold longer circulation time and 9.1-fold higher accumulation in H460 tumor than clinical formulation Alimta®. Moreover, CC₉-RCPs showed obviously better tumor penetration than RCPs. Remarkably, PEM-CC₉-RCPs at 12.5 mg PEM equiv./kg effectively suppressed growth of H460 xenografts and significantly prolonged mouse survival time as compared to PEM-RCPs and Alimta® controls. These lung cancer specific and reduction-responsive chimaeric polymersomes provide a unique pemetrexed nanoformulation for targeted lung cancer therapy.

STATEMENT OF SIGNIFICANCE

Multitargeted antifolate agent pemetrexed (PEM, Alimta®) is currently used for treating lung cancer patients and has low side-effects. However, PEM suffers from issues like fast elimination, low bioavailability, poor tumor cell selectivity and penetration. Scarce work on targeted delivery of PEM has been reported, partly because most conventional nanocarriers show a low and instable loading for hydrophilic, negatively charged drugs like PEM. Herewith, we report on lung cancer specific CSNIDARAC (CC₉) peptide-functionalized reduction-responsive chimaeric polymersomes (CC₉-RCPs) which showed efficient PEM encapsulation (14.2 wt%, 60 nm) and targeted delivery of PEM to H460 human lung cancer cells, leading to effective suppression of H460 tumor xenografts and significantly prolonged survival rates of mice than Alimta®. To the best of our knowledge, this represents a first report on targeted nanosystems that are capable of efficient loading and targeted delivery of PEM to lung tumors.

A novel gene expression-based prognostic scoring system to predict survival in gastric cancer

Analysis of gene expression patterns in gastric cancer (GC) can help to identify a comprehensive panel of gene biomarkers for predicting clinical outcomes and to discover potential new therapeutic targets. Here, a multi-step bioinformatics analytic approach was developed to establish a novel prognostic scoring system for GC. We first identified 276 genes that were robustly differentially expressed between normal and GC tissues, of which, 249 were found to be significantly associated with overall survival (OS) by univariate Cox regression analysis. The biological functions of 249 genes are related to cell cycle, RNA/ncRNA process, acetylation and extracellular matrix organization. A network was generated for view of the gene expression architecture of 249 genes in 265 GCs. Finally, we applied a canonical discriminant analysis approach to identify a 53-gene signature and a prognostic scoring system was established based on a canonical discriminant function of 53 genes. The prognostic scores strongly predicted patients with GC to have either a poor or good OS. Our study raises the prospect that the practicality of GC patient prognosis can be assessed by this prognostic scoring system.