Gemcitabine-loaded PEGylated unilamellar liposomes vs GEMZAR®: Biodistribution, pharmacokinetic features and in vivo antitumor activity

High-Load Gemcitabine Inorganic-Organic Hybrid Nanoparticles as an Image-Guided Tumor-Selective Drug-Delivery System to Treat Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) has a devastating prognosis without effective treatment options. Thus, there is an urgent need for more effective and safe therapies. Here, inorganic-organic hybrid nanoparticles (GMP-IOH-NPs) are presented as a novel drug-delivery system for the selective delivery of extraordinarily high concentrations of gemcitabine monophosphate (GMP), not only to the primary tumor but also to metastatic sites. GMP-IOH-NPs have a composition of [ZrO]2+ [GMP]2 - with GMP as drug anion (76% of total IOH-NP mass). Multiscale fluorescence imaging confirms an efficient uptake in tumor cells, independent of the activity of the human-equilibrative-nucleoside transporter (hENT1), being responsible for gemcitabine (GEM) transport into cells and a key factor for GEM resistance. Delivering already phosphorylated GMP via GMP-IOH-NPs into tumor cells also allows the cellular resistance induced by the downregulation of deoxycytidine kinase to be overcome. GMP-IOH-NPs show high accumulation in tumor lesions and only minor liver trapping when given intraperitoneally. GMP-IOH-NPs result in a higher antitumor efficacy compared to free GEM, which is further enhanced applying cetuximab-functionalized GMP-CTX-IOH-NPs. By maximizing the therapeutic benefits with high drug load, tumor-specific delivery, minimizing undesired side effects, overcoming mechanisms of chemoresistance, and preventing systemic GEM inactivation, GMP-IOH-NPs are anticipated to have a high chance to significantly improve current PDAC-patient outcome.

Nanoparticle biodistribution coefficients: A quantitative approach for understanding the tissue distribution of nanoparticles

The objective of this manuscript is to provide quantitative insights into the tissue distribution of nanoparticles. Published pharmacokinetics of nanoparticles in plasma, tumor and 13 different tissues of mice were collected from literature. A total of 2018 datasets were analyzed and biodistribution of graphene oxide, lipid, polymeric, silica, iron oxide and gold nanoparticles in different tissues was quantitatively characterized using Nanoparticle Biodistribution Coefficients (NBC). It was observed that typically after intravenous administration most of the nanoparticles are accumulated in the liver (NBC = 17.56 %ID/g) and spleen (NBC = 12.1 %ID/g), while other tissues received less than 5 %ID/g. NBC values for kidney, lungs, heart, bones, brain, stomach, intestine, pancreas, skin, muscle and tumor were found to be 3.1 %ID/g, 2.8 %ID/g, 1.8 %ID/g, 0.9 %ID/g, 0.3 %ID/g, 1.2 %ID/g, 1.8 %ID/g, 1.2 %ID/g, 1.0 %ID/g, 0.6 %ID/g and 3.4 %ID/g, respectively. Significant variability in nanoparticle distribution was observed in certain organs such as liver, spleen and lungs. A large fraction of this variability could be explained by accounting for the differences in nanoparticle physicochemical properties such as size and material. A critical overview of published nanoparticle physiologically-based pharmacokinetic (PBPK) models is provided, and limitations in our current knowledge about in vitro and in vivo pharmacokinetics of nanoparticles that restrict the development of robust PBPK models is also discussed. It is hypothesized that robust quantitative assessment of whole-body pharmacokinetics of nanoparticles and development of mathematical models that can predict their disposition can improve the probability of successful clinical translation of these modalities.

Optimal Physicochemical Properties of Antibody-Nanoparticle Conjugates for Improved Tumor Targeting

Tumor-targeted antibody (mAb)/fragment-conjugated nanoparticles (NPs) represent an innovative strategy for improving the local delivery of small molecules. However, the physicochemical properties of full mAb-NPs and fragment-NPs-that is, NP material, size, charge, as well as the targeting antibody moiety, and the linker conjugation strategies-remain to be optimized to achieve an efficient tumor targeting. A meta-analysis of 161 peer-reviewed studies is presented, which describes the use of tumor-targeted mAb-NPs and fragment-NPs from 2009 to 2021. The use of these targeted NPs is confirmed to result in significantly greater tumor uptake of NPs than that of naked NPs (7.9 ± 1.9% ID g^-1 versus 3.2 ± 0.6% ID g^-1 , respectively). The study further demonstrates that for lipidic NPs, fragment-NPs provide a significantly higher tumor uptake than full mAb-NPs. In parallel, for both polymeric and organic/inorganic NPs, full mAb-NPs yield a significant higher tumor uptake than fragment-NPs. In addition, for both lipidic and polymeric NPs, the tumor uptake is improved with the smallest sizes of the conjugates. Finally, the pharmacokinetics of the conjugates are demonstrated to be driven by the NPs and not by the antibody moieties, independently of using full mAb-NPs or fragment-NPs, confirming the importance of optimizing the NP design to improve the tumor uptake.

Liposomes: structure, composition, types, and clinical applications

Liposomes are now considered the most commonly used nanocarriers for various potentially active hydrophobic and hydrophilic molecules due to their high biocompatibility, biodegradability, and low immunogenicity. Liposomes also proved to enhance drug solubility and controlled distribution, as well as their capacity for surface modifications for targeted, prolonged, and sustained release. Based on the composition, liposomes can be considered to have evolved from conventional, long-circulating, targeted, and immune-liposomes to stimuli-responsive and actively targeted liposomes. Many liposomal-based drug delivery systems are currently clinically approved to treat several diseases, such as cancer, fungal and viral infections; more liposomes have reached advanced phases in clinical trials. This review describes liposomes structure, composition, preparation methods, and clinical applications.

Silymarin (milk thistle extract) as a therapeutic agent in gastrointestinal cancer

Silymarin contains a group of closely-related flavonolignan compounds including silibinin, and is extracted from Silybum marianum species, also called milk thistle. Silymarin has been shown to protect the liver in both experimental models and clinical studies. The chemopreventive activity of silymarin has shown some efficacy against cancer both in vitro and in vivo. Silymarin can modulate apoptosis in vitro and survival in vivo, by interfering with the expression of cell cycle regulators and apoptosis-associated proteins. In addition to its anti-metastatic activity, silymarin has also been reported to exhibit anti-inflammatory activity. The chemoprotective effects of silymarin and silibinin (its major constituent) suggest they could be applied to reduce the side effects and increase the anti-cancer effects of chemotherapy and radiotherapy in various cancer types, especially in gastrointestinal cancers. This review examines the recent studies and summarizes the mechanistic pathways and down-stream targets of silymarin in the therapy of gastrointestinal cancer.

Emerging pro-drug and nano-drug strategies for gemcitabine-based cancer therapy

Gemcitabine has been extensively applied in treating various solid tumors. Nonetheless, the clinical performance of gemcitabine is severely restricted by its unsatisfactory pharmacokinetic parameters and easy deactivation mainly because of its rapid deamination, deficiencies in deoxycytidine kinase (DCK), and alterations in nucleoside transporter. On this account, repeated injections with a high concentration of gemcitabine are adopted, leading to severe systemic toxicity to healthy cells. Accordingly, it is highly crucial to fabricate efficient gemcitabine delivery systems to obtain improved therapeutic efficacy of gemcitabine. A large number of gemcitabine pro-drugs were synthesized by chemical modification of gemcitabine to improve its biostability and bioavailability. Besides, gemcitabine-loaded nano-drugs were prepared to improve the delivery efficiency. In this review article, we introduced different strategies for improving the therapeutic performance of gemcitabine by the fabrication of pro-drugs and nano-drugs. We hope this review will provide new insight into the rational design of gemcitabine-based delivery strategies for enhanced cancer therapy.

A Liposomal Gemcitabine, FF-10832, Improves Plasma Stability, Tumor Targeting, and Antitumor Efficacy of Gemcitabine in Pancreatic Cancer Xenograft Models

Purpose

The clinical application of gemcitabine (GEM) is limited by its pharmacokinetic properties. The aim of this study was to characterize the stability in circulating plasma, tumor targeting, and payload release of liposome-encapsulated GEM, FF-10832.

Methods

Antitumor activity was assessed in xenograft mouse models of human pancreatic cancer. The pharmacokinetics of GEM and its active metabolite dFdCTP were also evaluated.

Results

In mice with Capan-1 tumors, the dose-normalized areas under the curve (AUCs) after FF-10832 administration in plasma and tumor were 672 and 1047 times higher, respectively, than after using unencapsulated GEM. The tumor-to-bone marrow AUC ratio of dFdCTP was approximately eight times higher after FF-10832 administration than after GEM administration. These results indicated that liposomal encapsulation produced long-term stability in circulating plasma and tumor-selective targeting of GEM. In mice with Capan-1, SUIT-2, and BxPC-3 tumors, FF-10832 had better antitumor activity and tolerability than GEM. Internalization of FF-10832 in tumor-associated macrophages (TAMs) was revealed by flow cytometry and confocal laser scanning microscopy, and GEM was efficiently released from isolated macrophages of mice treated with FF-10832. These results suggest that TAMs are one of the potential reservoirs of GEM in tumors.

Conclusion

This study found that FF-10832 had favorable pharmacokinetic properties. The liposomal formulation was more effective and tolerable than unencapsulated GEM in mouse xenograft tumor models. Hence, FF-10832 is a promising candidate for the treatment of pancreatic cancer.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11095-021-03045-5.

Nanotechnology improves the therapeutic efficacy of gemcitabine against a human hepatocellular carcinoma cell line and minimizes its in vivo side effects

Nanotechnology has become a promising approach for addressing cancer therapy limitations because it reduces side effects and increases the efficacy of antineoplastic agents. Therefore, this research was designed to compare the in vitro therapeutic efficacy and in vivo adverse effects of gemcitabine (GEM) and gemcitabine-loaded silver nanoparticles (GEM-AgNPs). GEM molecules were successfully attached to AgNP surfaces with a homogenous and spherical shape. The zeta size of AgNPs and GEM-AgNPs was 79.35 ± 3.2 and 75.1 ± 7 nm, respectively. The anticancer effect of AgNPs and GEM-AgNPs was investigated against a human hepatocellular carcinoma cell line (HepG2), and cytotoxic activity was evaluated by MTT assay. Apoptosis/necrosis and cell cycle arrest were also assessed. The cytotoxic activity was recorded in a concentration-dependent way. The findings have shown that GEM-AgNPs induced a better cytotoxic effect with an IC₅₀ value of 13.63 μg/mL compared to GEM (IC₅₀ value of 24.19 μg/mL) or AgNPs alone (IC₅₀ value of 50.6 μg/mL). GEM-AgNPs induced pre-G1 arrest and apoptotic/necrotic cell death. Our in vivo analysis involved the use of 40 male rats assigned equally into the control rats, and rats injected intraperitoneally with GEM (134 mg/kg), AgNPs (1 mg/kg), and GEM-AgNPs (134 mg/kg). GEM and GEM-AgNPs were administered on the 1st, 7th, and 14th day of the experiment. Intraperitoneal GEM injection induced marked hematological, biochemical, hepatorenal, and histopathological alterations, while the loading of GEM in AgNPs to some extent ameliorated these alterations and significantly improved its therapeutic efficacy against HepG2 cells. These findings indicate the potential use of GEM-AgNPs in the clinical setting for anticancer treatment.

Glypican-1-targeted and gemcitabine-loaded liposomes enhance tumor-suppressing effect on pancreatic cancer

Liposomes (LPs) as promising drug delivery systems are widely applied in cancer therapy. This study aimed to investigate the effect of glypican-1 (GPC1)-targeted and gemcitabine (GEM)-loaded LP [GPC1-LP (GEM)] on cell proliferation and apoptosis in PANC-1s, as well as on orthotopic pancreatic cancer (PDAC) mice. The GPC1-LP (GEM) and LP (GEM) was prepared, and then the size distribution of GPC1-LP (GEM) was analyzed by dynamic light scattering (DLS). In vitro drug release assay of GPC1-LP (GEM) and LP (GEM) was performed, and the expression of GPC1 in PANC1 cells was detected as well. Next, the effects of free GEM, LP (GEM) and GPC1-LP (GEM) on cell viability, clone number, and apoptosis, as well as the expression of proteins associated with apoptosis were measured in 239T and PANC-1 cells. Furthermore, the body weight and tumor size of orthotopic PDAC mice were evaluated following the treatment of free GEM, LP (GEM) or GPC1-LP (GEM). LP (GEM) and GPC1-LP (GEM) were successfully prepared with a successful GEM release within 24 h. In addition, GPC1 was positively expressed in PANC-1 cells but not 293T cells. These findings provided more insights into the anti-tumor potential for the biomedical application of GPC1-LP (GEM) in PDAC.

Diagnostic and therapeutic evaluation of folate-targeted paclitaxel and vinorelbine encapsulating theranostic liposomes for non-small cell lung cancer

NSCLC is the most common type of lung cancer. However, non-specific contrast agents, radiopharmaceuticals, and treatment methods are insufficient in early diagnosis and eradication of all tumor tissue. Therefore, the formulation of a novel, targeted, specific theranostic agents possess critical importance. In our previous study, paclitaxel and vinorelbine encapsulating, Tc-99m radiolabeled, folate targeted, nanosized liposomes were formulated and found promising due to characterization properties, high cellular uptake, and cytotoxicity. In this study, in vivo therapeutic and diagnostic efficacy of liposomal formulations were tested by biodistribution study, evaluation of tumor growth inhibition, and histopathologic examination after in vitro assays on LLC1 cells. Both actively and passively targeted liposomal formulations exhibited high cellular uptake, and co-drug encapsulating liposomes showed a greater cytotoxicity profiles than free drug combination in LLC1 cells. By the results of biodistribution studies performed in NSCLC tumor-bearing C57BL/6 mice, the uptake of radiolabeled, actively folate targeted, co-drug encapsulating liposomal formulation was found to be higher in tumor tissue when compared to non-actively targeted one. Also, more effective treatment was achieved by using folate-targeted, co-drug encapsulating liposomal formulation when compared to free drugs combination according to changes in tumor size of mice. Furthermore, liposomal formulations showed lower toxicity compared to free drug combinations in the toxicity study considering body weight. Moreover, according to the histopathological study, folate targeted, co-drug encapsulating liposomes not only inhibited the tumor growth effectively but also restricted the lung metastasis entirely.

Liposomal Delivery of Mycophenolic Acid With Quercetin for Improved Breast Cancer Therapy in SD Rats

The present study explores the influence of mycophenolic acid (MPA) in combination therapy with quercetin (QC) (impeding MPA metabolic rate) delivered using the liposomal nanoparticles (LNPs). Mycophenolic acid liposome nanoparticles (MPA-LNPs) and quercetin liposome nanoparticles (QC-LNPs) were individually prepared and comprehensively characterized. The size of prepared MPA-LNPs and QC-LNPs were found to be 183 ± 13 and 157 ± 09.8, respectively. The in vitro studies revealed the higher cellular uptake and cytotoxicity of combined therapy (MPA-LNPs + QC-LNPs) compared to individual ones. Moreover pharmacokinetics studies in female SD-rat shown higher T 1 / 2 value (1.94 fold) of combined therapy compared to MPA. Furthermore, in vivo anticancer activity in combination of MPA-LNPs and QC-LNPs was also significantly higher related to other treatments groups. The combination therapy of liposomes revealed the new therapeutic approach for the treatment of breast cancer.

Overcoming Nanoparticle-Mediated Complement Activation by Surface PEG Pairing

Many PEGylated nanoparticles activate the complement system, which is an integral component of innate immunity. This is of concern as uncontrolled complement activation is potentially detrimental and contributes to disease pathogenesis. Here, it is demonstrated that, in contrast to carboxyPEG₂₀₀₀-stabilized poly(lactic-co-glycolic acid) nanoparticles, surface camouflaging with appropriate combinations and proportions of carboxyPEG₂₀₀₀ and methoxyPEG₅₅₀ can largely suppress nanoparticle-mediated complement activation through the lectin pathway. This is attributed to the ability of the short, rigid methoxyPEG₅₅₀ chains to laterally compress carboxyPEG₂₀₀₀ molecules to become more stretched and assume an extended, random coil configuration. As supported by coarse-grained molecular dynamics simulations, these conformational attributes minimize statistical protein binding/intercalation, thereby affecting sequential dynamic processes in complement convertase assembly. Furthermore, PEG pairing has no additional effect on nanoparticle longevity in the blood and macrophage uptake. PEG pairing significantly overcomes nanoparticle-mediated complement activation without the need for surface functionalization with complement inhibitors.

Antitumor activity of gemcitabine hydrochloride loaded lipid polymer hybrid nanoparticles (LPHNs): In vitro and in vivo

The present study demonstrated the application of gemcitabine hydrochloride (GEM) loaded lipid polymer hybrid nanoparticles (LPHNs) for the enhancement the chemotherapeutic response. GEM, which is an anti-tumor drug, is frequently utilized for the treatment of non-small cell lung cancer, breast cancer and pancreatic cancer. GEM loaded LPHNs were formed and examined for pharmacokinetic profile and in vivo anticancer activity. Modified double emulsion solvent evaporation method was employed in the preparation of the LPHNs. Cytotoxicities of the GEM loaded LPHNs formulation were evaluated on MCF-7 and MDA-MB-231 cells by MTT assays. Pharmacokinetics and in vivo anticancer efficacy studies were conducted following intraperitoneal administration in female Sprague-Dawley rats. In vivo pharmacokinetic studies in rats exhibited the advantage of the GEM loaded LPHNs over commercial product Gemko® and the GEM loaded LPHNs had longer circulation time. The half-life of GEM in LPHNs formulation was notable advanced (4.2 folds) comparing to commercial product of GEM (native). These findings indicated that GEM loaded LPHNs can be used for enhancing antitumor efficacy for breast cancer treatment.

Meta-Analysis of Nanoparticle Delivery to Tumors Using a Physiologically Based Pharmacokinetic Modeling and Simulation Approach

Numerous studies have engineered nanoparticles with different physicochemical properties to enhance the delivery efficiency to solid tumors, yet the mean and median delivery efficiencies are only 1.48% and 0.70% of the injected dose (%ID), respectively, according to a study using a nonphysiologically based modeling approach based on published data from 2005 to 2015. In this study, we used physiologically based pharmacokinetic (PBPK) models to analyze 376 data sets covering a wide range of nanomedicines published from 2005 to 2018 and found mean and median delivery efficiencies at the last sampling time point of 2.23% and 0.76%ID, respectively. Also, the mean and median delivery efficiencies were 2.24% and 0.76%ID at 24 h and were decreased to 1.23% and 0.35%ID at 168 h, respectively, after intravenous administration. While these delivery efficiencies appear to be higher than previous findings, they are still quite low and represent a critical barrier in the clinical translation of nanomedicines. We explored the potential causes of this poor delivery efficiency using the more mechanistic PBPK perspective applied to a subset of gold nanoparticles and found that low delivery efficiency was associated with low distribution and permeability coefficients at the tumor site (P < 0.01). We also demonstrate how PBPK modeling and simulation can be used as an effective tool to investigate tumor delivery efficiency of nanomedicines.

Novel drug combination nanoparticles exhibit enhanced plasma exposure and dose-responsive effects on eliminating breast cancer lung metastasis

Early diagnosis along with new drugs targeted to cancer receptors and immunocheckpoints have improved breast cancer survival. However, full remission remains elusive for metastatic breast cancer due to dose-limiting toxicities of heavily used, highly potent drug combinations such as gemcitabine and paclitaxel. Therefore, novel strategies that lower the effective dose and improve safety margins could enhance the effect of these drug combinations. To this end, we developed and evaluated a novel drug combination of gemcitabine and paclitaxel (GT). Leveraging a simple and scalable drug-combination nanoparticle platform (DcNP), we successfully prepared an injectable GT combination in DcNP (GT DcNP). Compared to a Cremophor EL/ethanol assisted drug suspension in buffer (CrEL), GT DcNP exhibits about 56-fold and 8.6-fold increases in plasma drug exposure (area under the curve, AUC) and apparent half-life of gemcitabine respectively, and a 2.9-fold increase of AUC for paclitaxel. Using 4T1 as a syngeneic model for breast cancer metastasis, we found that a single GT (20/2 mg/kg) dose in DcNP nearly eliminated colonization in the lungs. This effect was not achievable by a CrEL drug combination at a 5-fold higher dose (i.e., 100/10 mg/kg GT). A dose-response study indicates that GT DcNP provided a therapeutic index of ~15.8. Collectively, these data suggest that GT DcNP could be effective against advancing metastatic breast cancer with a margin of safety. As the DcNP formulation is intentionally designed to be simple, scalable, and long-acting, it may be suitable for clinical development to find effective treatment against metastatic breast cancer.

Local release of gemcitabine via in situ UV-crosslinked lipid-strengthened hydrogel for inhibiting osteosarcoma

Osteosarcoma is among the most common malignant bone tumors in human skeletal system. The conventional treatment of osteosarcoma mainly consists of combining neoadjuvant chemotherapy with surgical approach. However, it is crucial to design an artificial implant that possesses excellent biomechanical properties and is capable of sustaining local release of chemotherapeutics. In this study, we envision that the highly efficient combination of gemcitabine (GEM) hydrochloride loaded liposomes with gelatin methacryloyl (GelMA) of in situ photocrosslinkable hydrogel will lead to a multifunctional implant with unique antitumor, mechanical, and biodegradable properties. A sustained controlled release was observed; more specifically, the release of GEM in vitro lasted for 4 days long. Furthermore, its capability in killing MG63 cells was further explored by using the lixivium of GEM-Lip@Gel and GEM-GelMA hydrogel in vitro (composite hydrogel by GEM loaded liposomes blending with GelMA, short for GEM-Lip@Gel), which agreed with the drug release outcome. In addition, these hydrogel showed excellent ability in inhibiting osteosarcoma in vivo by Balb/c mice bearing MG63 cells. Therefore, GEM-loaded lipo-hydrogel certainly has presented itself as a promising strategy for the development of implant in the field of osteosarcoma treatment.

Gemcitabine-loaded Folic Acid Tagged Liposomes: Improved Pharmacokinetic and Biodistribution Profile

BACKGROUND

Gemcitabine (GEM) is found effective in the treatment of many solid tumors. However, its use is restricted due to its small circulation half-life, fast metabolism and low capacity for selective tumor uptake. Folate receptors (FRs) have been recognized as cellular surface markers, which can be used for cancer targeting. PEGylated liposomes decorated with folic acid have been investigated for several anticancer agents not only to extend plasma half-life but also for tumor targeting via folic acid receptors which overexpressed on tumor cell surface.

OBJECTIVE

Therefore, the objective of the present study was to prepare GEM-loaded folic acid tagged liposomes to improve the pharmacokinetics and tumor distribution of GEM.

METHODS

The blank folate-targeted liposomes composed of HSPC/DSPE-mPEG2000/DSPE-mPEG-Folic acid were prepared first by thin film hydration technique. GEM was then loaded into liposomes by remote loading technique. The optimized liposomal formulations were evaluated in vitro for GEM release using dialysis technique, HeLa cell uptake using FACS technique, and cytotoxicity using MTT dye reduction assay. The comparative in vivo pharmacokinetic and biodistribution characteristics of radiolabeled (99mTc-labeled) plain GEM solution, and all liposomal formulations (conventional:CLs; stealth: SLs; folate targeted: FTLs) were evaluated in mice model.

RESULTS

GEM-loaded FTLs showed sustained release profile, efficient uptake by HeLa cells and greater cytotoxicity. Further, FTLs displayed significantly improved pharmacokinetics, and biodistribution profile of loaded GEM.

CONCLUSION

In conclusion, the developed GEM-loaded folic acid receptor-targeted liposomal formulation could be a promising and potential alternative formulation for further development.

Attempts to strengthen and simplify the tumor vascular normalization strategy using tumor vessel normalization promoting nanomedicines

Tumor vascular normalization theory opened the door for the rational use of antiangiogenic agents and chemotherapeutics.

A new therapeutic combination for osteosarcoma: Gemcitabine and Clofazimine co-loaded liposomal formulation

Osteosarcoma is the most common cancer in bone. Drug resistance is a challenge of current treatments that needs to be improved with novel treatment strategies. In this research, a new dual drug delivery system was developed with Gemcitabine (GEM) and Clofazimine (CLF) co-loaded liposome formulations. GEM is a well-known anticancer agent and CLF is a leprostatic and anti-inflammatory drug recently recognized as effective on cancer. GEM and CLF co-loaded liposomal formulation was achieved with compartmentalization as hydrophilic GEM being in core and lipophilic CLF sequestering in lipid-bilayer. Liposomes had high encapsulation efficiency (above 90%, GEM and above 80%, CLF). CLF release was enhanced while GEM release was slowed down in co-loaded liposomes compared to single cases. GEM/CLF co-loaded liposomes significantly enhanced cytotoxicity than GEM or CLF loaded liposomes on osteosarcoma cell line. CLF and GEM had synergistic effect (CI < 1). Results of flow cytometry showed higher apoptotic cell ratio, caspase-3 activity, mitochondrial membrane depolarized cells' ratio for GEM/CLF co-loaded liposome treatments than other liposomes. Cytotoxicity of CLF on bone cancer cells and also its synergistic effect with GEM on osteosarcoma is reported for the first time with this study. CLF's loading with GEM into liposome was also a new approach for enhancement of anticancer effect on Saos-2 cells. Therefore, GEM/CLF co-loaded liposomal delivery system is proposed as a novel approach for treatment of osteosarcoma.

Hyaluronic acid conjugated multi-walled carbon nanotubes for colon cancer targeting

Purpose of the present research was to evaluate in vitro and in vivo potential of gemcitabine (GEM) loaded hyaluronic acid (HA) conjugated PEGylated multi-walled carbon nanotubes (GEM/HA-PEG-MWCNTs) for effective colon cancer targeting. HA was conjugated onto the surface of aminated or PEGylated MWCNTs which were evaluated for size, surface morphology, entrapment efficiency (~90%), in vitro drug release, in vitro cytotoxicity and in vivo performance in Sprague Dawley rats. In vitro release showed that the release rate of GEM in acidic conditions (pH 5.3) was faster than physiological conditions (PBS, pH 7.4) followed by a sustained release pattern. The developed GEM/HA-PEG-MWCNTs indicated significantly less hemolytic toxicity (7.73 ± 0.4%) paralleled to free GEM (18.71 ± 0.44%) and showed higher cytotoxicity against HT-29 colon cancer cell line. The antitumor study assured that GEM/HA-PEG-MWCNTs significantly reduced tumor volume as compared to free GEM and increased survival rate without noticeable loss in body weight. In vivo studies showed an improvement in pharmacokinetics in terms of remarkable escalation in mean residence time, half-life, AUC, AUMC, median survival time in tumor bearing rats treated with GEM/HA-MWCNTs and GEM/HA-PEG-MWCNTs as compared to free GEM (p ˂ 0.001). These outcomes proved engineered MWCNTs as a safe and effective nanomedicine in colon cancer targeting.

Development and characterization of gemcitabine hydrochloride loaded lipid polymer hybrid nanoparticles (LPHNs) using central composite design

Lipid polymer hybrid nanoparticles (LPHNs) combine the characteristics and beneficial properties of both polymeric nanoparticles and liposomes. The objective of this study was to design and optimize gemcitabine hydrochloride loaded LPHNs based on the central composite design approach. PLGA 50:50/PLGA 65:35 mass ratio (w/w), soya phosphatidylcholine (SPC)/polymer mass ratio (%, w/w) and amount of DSPE-PEG were chosen as the investigated independent variables. The LPHNs were prepared with modified double emulsion solvent evaporation method and characterized by testing their particle size, encapsulation efficiency, and cumulative release. The composition of optimal formulation was determined as 1,5 (w/w) PLGA 50:50/PLGA 65:35 mass ratio, 30% (w/w) SPC/polymer mass ratio and 15 mg DSPE-PEG. The results showed that the optimal formulation gemcitabine hydrochloride loaded LPHNs had encapsulation efficiency of 45,2%, particle size of 237 nm and cumulative release of 62,3% at the end of 24 h. The morphology of LPHNs was found to be spherical by transmission electron microscopy (TEM) observation. Stability studies showed that LPHNs were physically stable until 12 months at 4 °C and 9 months at 25 °C/60% RH. The results suggest that the LPHNs can be an effective drug delivery system for hydrophilic active pharmaceutical ingredient.

Using Atomic Force Microscopy to Predict Tumor Specificity of ICAM1 Antibody-Directed Nanomedicines

Atomic force microscopy (AFM) is a powerful tool to detect in vitro antibody-antigen interactions. To date, however, AFM-measured antibody-antigen interactions have yet to be exploited to predict in vivo tumor specificity of antibody-directed nanomedicines. In this study, we have utilized AFM to directly measure the biomechanical interaction between live triple negative breast cancer (TNBC) cells and an antibody against ICAM1, a recently identified TNBC target. For the first time, we provide proof-of-principle evidence that in vitro TNBC cell-ICAM1 antibody binding force measured by AFM on live cells more precisely correlates with in vivo tumor accumulation and therapeutic efficacy of ICAM1 antibody-directed liposomes than ICAM1 gene and surface protein overexpression levels. These studies demonstrate that live cell-antibody binding force measurements may be used as a novel in vitro metric for predicting the in vivo tumor recognition of antibody-directed nanomedicines.

Effects of Silymarin-Loaded Nanoparticles on HT-29 Human Colon Cancer Cells

Background and objective: Previous studies have demonstrated the anti-cancer effects of silymarin (SLM). However, the low bioavailability of SLM has restricted its use. This study investigated the toxic effect of nanostructured SLM encapsulated in micelles (Nano-SLM) on the growth of the HT-29 human colon cancer cell line. Materials and methods: HT-29 cells were treated with 25 μM/mL of SLM or Nano-SLM for 48 h. MTT and colony formation assays were used to assess the cytotoxicity and proliferation of HT-29 cells, respectively. The cells were stained with annexin V/PI for assessment of apoptosis. Results: MTT assays revealed that Nano-SLM treatment was able to exert a more pronounced toxic effect on the HT-29 cells as compared to free SLM treatment (p < 0.01). In the Nano-SLM-treated cells, colony numbers were significantly reduced in comparison to the free SLM-treated cells (p < 0.01). Apoptotic and necrotic indexes of Nano-SLM-treated HT-29 cells were also significantly increased in comparison to those of the free SLM-treated cells (p < 0.01). The viability, proliferation and apoptosis of healthy cells (NIH-3T3 cells) were not changed in response to Nano-SLM or SLM. Conclusions: Our results indicate that Nano-SLM enhances the anti-cancer effects of SLM against human colon cancer cells.

Cell Membrane-Based Nanoreactor To Mimic the Bio-Compartmentalization Strategy of a Cell

Organelles of eukaryotic cells are structures made up of membranes, which carry out a majority of functions necessary for the surviving of the cell itself. Organelles also differentiate the prokaryotic and eukaryotic cells, and are arranged to form different compartments guaranteeing the activities for which eukaryotic cells are programmed. Cell membranes, containing organelles, are isolated from cancer cells and erythrocytes and used to form biocompatible and long-circulating ghost nanoparticles delivering payloads or catalyzing enzymatic reactions as nanoreactors. In this attempt, red blood cell membranes were isolated from erythrocytes, and engineered to form nanoerythrosomes (NERs) of 150 nm. The horseradish peroxidase, used as an enzyme model, was loaded inside the aqueous compartment of NERs, and its catalytic reaction with Resorufin was monitored. The resulting nanoreactor protected the enzyme from proteolytic degradation, and potentiated the enzymatic reaction in situ as demonstrated by maximal velocity (V_max) and Michaelis constant (K_m), thus suggesting the high catalytic activity of nanoreactors compared to the pure enzymes.

Development of Optimized, Inhalable, Gemcitabine-Loaded Gelatin Nanocarriers for Lung Cancer

BACKGROUND

Aerosol delivery of chemotherapeutic nanocarriers represents a promising alternative for lung cancer therapy. This study optimized gemcitabine (Gem)-loaded gelatin nanocarriers (GNCs) cross-linked with genipin (Gem-GNCs) to evaluate their potential for nebulized lung cancer treatment.

METHODS

Gem-GNCs were prepared by two-step desolvation and optimized through Taguchi design and characterized for physicochemical properties. Particle size and morphology were confirmed by scanning and transmission electron microscopy. In vitro release of Gem from Gem-GNCs performed in Dulbecco's phosphate-buffered saline and simulated lung fluid was evaluated to determine release mechanisms. Particle size stability was assessed under varying pH. Differential scanning calorimetry and powder X-ray diffraction were used to determine the presence and stability of Gem-GNC components and amorphization of Gem, respectively. Gem-GNC efficacy within A549 and H460 cells was evaluated using MTT assays. Mucus rheology upon treatment with Gem-GNCs, lactose, and normal saline control was measured. Andersen cascade impaction identified the aerodynamic particle size distribution of the nebulized formulation.

RESULTS

Gem-GNCs had particle size, zeta potential, entrapment efficiency, and loading efficiency of 178 ± 7.1 nm, -18.9 mV, 92.5%, and 9.1%, respectively. The Gem and formulation excipients where molecularly dispersed and configured amorphously. Gem-GNCs were stable at pH 5.4-7.4 for 72 hours. Gem release from Gem-GNCs was governed by non-Fickian controlled release due to diffusion/erosion from a matrix-based nanocarrier. Gem-GNCs elicited a 40% reduction of the complex viscosity η*(1 Hz) of human bronchial epithelial cell mucus containing 3 wt% solids to mimic mild airway disease. The nebulized Gem-GNCs had a mass median aerodynamic diameter (MMAD) of 2.0 ± 0.16 μm, geometric standard deviation (GSD) of 2.7 ± 0.16, and fine particle fraction (FPF) of 75.2% ± 2.4%. The Gem-GNC formulation did not outperform the Gem solution in A549 cells. However, in H460, Gem-GNCs outperformed the Gem IC50 reduction by ∼5-fold at 48 and 10-fold 72 hours.

CONCLUSION

Stable, effective, and sustained-release Gem-GNCs were developed. The nebulized Gem-GNCs had satisfactory MMAD, GSD, and FPF and the formulation reduced the dynamic complex viscosity of mucus consistent with increased mobility of nanoparticles.

Smart thermosensitive liposomes for effective solid tumor therapy and in vivo imaging

In numerous studies, liposomes have been used to deliver anticancer drugs such as doxorubicin to local heat-triggered tumor. Here, we investigate: (i) the ability of thermosensitive liposomal nanoparticle (TSLnp) as a delivery system to deliver poorly membrane-permeable anticancer drug, gemcitabine (Gem) to solid pancreatic tumor with the aid of local mild hyperthermia and, (ii) the possibility of using gadolinium (Magnevist®) loaded-TSLnps (Gd-TSLnps) to increase magnetic resonance imaging (MRI) contrast in solid tumor. In this study, we developed and tested gemcitabine-loaded thermosensitive liposomal nanoparticles (Gem-TSLnps) and gadolinium-loaded thermosensitive liposomal nanoparticles (Gd-TSLnps) both in in-vitro and in-vivo. The TSLnps exhibited temperature-dependent release of Gem, at 40-42°C, 65% of Gem was released within 10 min, whereas < 23% Gem leakage occurred at 37°C after a period of 2 h. The pharmacokinetic parameters and tissue distribution of both Gem-TSLnps and Gd-TSLnps were significantly greater compared with free Gem and Gd, while Gem-TSLnps plasma clearance was reduced by 17-fold and that of Gd-TSLpns was decreased by 2-fold. Area under the plasma concentration time curve (AUC) of Gem-TSLnps (35.17± 0.04 μghr/mL) was significantly higher than that of free Gem (2.09 ± 0.01 μghr/mL) whereas, AUC of Gd-TSLnps was higher than free Gd by 3.9 fold high. TSLnps showed significant Gem accumulation in heated tumor relative to free Gem. Similar trend of increased Gd-TSLnps accumulation was observed in non-heated tumor compared to that of free Gd; however, no significant difference in MRI contrast enhancement between free Gd and Gd-TSLnps ex-vivo tumor images was observed. Despite Gem-TSLnps dose being half of free Gem dose, antitumor efficacy of Gem-TSLnps was comparable to that of free Gem(Gem-TSLnps 10 mg Gem/kg compared with free Gem 20 mg/kg). Overall, the findings suggest that TSLnps may be used to improve Gem delivery and enhance its antitumor activity. However, the formulation of Gd-TSLnp needs to be fully optimized to significantly enhance MRI contrast in tumor.

Improved metabolic stability and therapeutic efficacy of a novel molecular gemcitabine phospholipid complex

The aim of the present research is to increase lipid solubility, metabolic stability and therapeutic efficacy of water soluble gemcitabine (GEM) via phospholipid complex (PC) formation. A novel phospholipid complex of GEM was successfully prepared and optimized. Physical interaction of GEM with phospholipid was evaluated by DSC, FT-IR, ¹H NMR, ³¹P-NMR and P-XRD. SEM images of GEM-PC showed rough structure and TEM images of diluted aqueous dispersion of GEM-PC showed micellar structure. In silico study also revealed the significant interaction between drug and phospholipid. GEM-PC demonstrated sustained drug release pattern and high plasma stability (∼2.2 fold) in vitro as compared to GEM. Increased in vitro cytotoxicity and apoptosis were observed with GEM-PC, when incubated with human pancreas adenocarcinoma cell lines. In vivo pharmacokinetics showed the almost 2 fold increase in AUC_0-∞ (area under curve) with phospholipid complex (8983.26ngh/ml) as compared with GEM (4371.18ngh/ml) and GEMITA (4689.29ngh/ml). Toxicity studies signify the safety of GEM-PC over GEMITA. Pharmacodynamics studies in pancreatic tumor model further revealed higher efficacy of GEM-PC than GEMITA. These findings suggested the higher potential of phospholipid based technology for the enhancement of metabolic stability and therapeutic efficacy of GEM.

Encapsulating a Hydrophilic Chemotherapeutic into Rod-like Nanoparticles of a Genetically Encoded Asymmetric Triblock Polypeptide Improves its Efficacy

Encapsulating hydrophilic chemotherapeutics into the core of polymeric nanoparticles can improve their therapeutic efficacy by increasing their plasma half-life, tumor accumulation and intracellular uptake, and by protecting them from premature degradation. To achieve these goals, we designed a recombinant asymmetric triblock polypeptide (ATBP) that self-assembles into rod-shaped nanoparticles, and which can be used to conjugate diverse hydrophilic molecules, including chemotherapeutics, into their core. These ATBPs consist of three segments: a biodegradable elastin-like polypeptide, a hydrophobic Tyrosine-rich segment, and a short Cysteine-rich segment, that spontaneously self-assemble into rod-shaped micelles. Covalent conjugation of a structurally diverse set of hydrophilic small molecules, including a hydrophilic chemotherapeutic -gemcitabine- to the Cysteine residues also leads to formation of nanoparticles over a range of ATBP concentrations. Gemcitabine-loaded ATBP nanoparticles have significantly better tumor regression compared to free drug in a murine cancer model. This simple strategy of encapsulation of hydrophilic small molecules by conjugation to an ATBP can be used to effectively deliver a range of water-soluble drugs and imaging agents in vivo.

Plasmonic nanocarrier grid-enhanced Raman sensor for studies of anticancer drug delivery

Targeted drug delivery systems using nanoparticle nanocarriers offer remarkable promise for cancer therapy by discriminating against devastating cytotoxicity of chemotherapeutic drugs to healthy cells. To aid in the development of new drug nanocarriers, we propose a novel plasmonic nanocarrier grid-enhanced Raman sensor which can be applied for studies and testing of drug loading onto the nanocarriers, attachment of targeting ligands, dynamics of drug release, assessment of nanocarrier stability in biological environment, and general capabilities of the nanocarrier. The plasmonic nanogrid sensor offers strong Raman enhancement due to the overlapping plasmonic fields emanating from the nearest-neighbor gold nanoparticle nanocarriers and creating the enhancement "hot spots". The sensor has been tested for immobilization of an anticancer drug gemcitabine (2',2'-difluoro-2'-deoxycytidine, GEM) which is used in treatment of pancreatic tumors. The drawbacks of currently applied treatment include high systemic toxicity, rapid drug decay, and low efficacy (ca. 20%). Therefore, the development of a targeted GEM delivery system is highly desired. We have demonstrated that the proposed nanocarrier SERS sensor can be utilized to investigate attachment of targeting ligands to nanocarriers (attachment of folic acid ligand recognized by folate receptors of cancer cells is described). Further testing of the nanocarrier SERS sensor involved drug release induced by lowering pH and increasing GSH levels, both occurring in cancer cells. The proposed sensor can be utilized for a variety of drugs and targeting ligands, including those which are Raman inactive, since the linkers can act as the Raman markers, as illustrated with mercaptobenzoic acid and para-aminothiophenol.

Biodistribution of Self-Assembling Polymer-Gemcitabine Conjugate after Systemic Administration into Orthotopic Pancreatic Tumor Bearing Mice

Therapeutic efficacy of gemcitabine (GEM) is severely limited due to its rapid metabolism by enzymatic deamination in vivo. We recently determined its therapeutic efficacy before (F-GEM) and after conjugation to poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate) (mPEG-b-PCC-g-GEM-g-DC, abbreviated as P-GEM) in subcutaneous and orthotopic pancreatic tumor bearing mice. In this study, pharmacokinetic (PK) parameters and biodistribution profiles of F-GEM and P-GEM were determined after intravenous injection into orthotopic pancreatic tumor bearing NSG mice. To assess the short-term toxicity, the levels of hematological, hepatic, and renal injury markers were measured after 24 h postadministration into these mice. P-GEM was distributed to all the major organs, with higher accumulation in the liver, spleen, and tumor compared to F-GEM. Area under the curve (AUC), elimination half-life (t_1/2), and mean residence time (MRT) of P-GEM treated group were significantly higher compared to those of F-GEM treated group: 246,425 ± 1605 vs 83,591 ± 1844 ng/mL × h as AUC, 5.77 ± 2.02 vs 1.99 ± 0.09 h as t_1/2, and 4.45 ± 0.15 vs 1.12 ± 0.13 h as MRT. Further, P-GEM exhibited negligible systemic toxicity as evidenced by almost similar alanine aminotransferase (ALT) and aspartate aminotransferase (AST) values for both P-GEM and F-GEM. These results suggest that P-GEM protects GEM from degradation and provides sustained drug release, resulting in enhanced GEM delivery to the tumor by more than 2.5-fold compared to F-GEM. Hence, P-GEM is a promising gemcitabine conjugated polymeric micelle for treating pancreatic cancer.

Recent advances in drug delivery strategies for improved therapeutic efficacy of gemcitabine

Gemcitabine (2',2'-difluoro-2'-deoxycytidine; dFdC) is an efficacious anticancer agent acting against a wide range of solid tumors, including pancreatic, non-small cell lung, bladder, breast, ovarian, thyroid and multiple myelomas. However, short plasma half-life due to metabolism by cytidine deaminase necessitates administration of high dose, which limits its medical applicability. Further, due to its hydrophilic nature, it cannot traverse cell membranes by passive diffusion and, therefore, enters via nucleoside transporters that may lead to drug resistance. To circumvent these limitations, macromolecular prodrugs and nanocarrier-based formulations of Gemcitabine are gaining wide recognition. The nanoformulations based approaches by virtue of their controlled release and targeted delivery have proved to improve bioavailability, increase therapeutic efficacy and reduce adverse effects of the drug. Furthermore, the combination of Gemcitabine with other anticancer agents as well as siRNAs using nanocarriers has also been investigated in order to enhance its therapeutic potential. This review deals with challenges and recent advances in the delivery of Gemcitabine with particular emphasis on macromolecular prodrugs and nanomedicines.

PDE5 Inhibitors-Loaded Nanovesicles: Physico-Chemical Properties and In Vitro Antiproliferative Activity

Novel therapeutic approaches are required for the less differentiated thyroid cancers which are non-responsive to the current treatment. In this study we tested an innovative formulation of nanoliposomes containing sildenafil citrate or tadalafil, phosphodiesterase-5 inhibitors, on two human thyroid cancer cell lines (TPC-1 and BCPAP). Nanoliposomes were prepared by the thin layer evaporation and extrusion methods, solubilizing the hydrophilic compound sildenafil citrate in the aqueous phase during the hydration step and dissolving the lipophilic tadalafil in the organic phase. Nanoliposomes, made up of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine monohydrate (DPPC), cholesterol, and N-(carbonyl-methoxypolyethylene glycol-2000)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE-mPEG2000) (6:3:1 molar ratio), were characterized by a mean diameter of ~100 nm, a very low polydispersity index (~0.1) and a negative surface charge. The drugs did not influence the physico-chemical properties of the systems and were efficiently retained in the colloidal structure. By using cell count and MTT assay, we found a significant reduction of the viability in both cell lines following 24 h treatment with both nanoliposomal-encapsulated drugs, notably greater than the effect of the free drugs. Our findings demonstrate that nanoliposomes increase the antiproliferative activity of phosphodiesterase-5 inhibitors, providing a useful novel formulation for the treatment of thyroid carcinoma.

Tumor stromal disrupting agent enhances the anticancer efficacy of docetaxel loaded PEGylated liposomes in lung cancer

AIM

Therapeutic efficacy of anticancer nanomedicine is compromised by tumor stromal barriers. The present study deals with the development of docetaxel loaded PEGylated liposomes (DTXPL) and to investigate the effect of tumor stroma disrupting agent, telmisartan, on anticancer efficacy of DTXPL.

METHODS

DTXPL was prepared using proprietary modified hydration method. Effect of oral telmisartan treatment on tumor uptake of coumarin-6 liposomes and anticancer efficacy of DTXPL was evaluated in orthotopic xenograft lung tumor bearing mice.

RESULTS

DTXPL (105.7 ± 3.8 nm) showed very high physical stability, negligible hemolysis, 428% enhancement in bioavailability with significantly higher intratumoral uptake. Marked reduction in collagen-I, MMP2/9 and lung tumor weight were observed in DTXPL+telmisartan group.

CONCLUSION

Combination of DTXPL with telmisartan could significantly enhance clinical outcome in lung cancer.

Emerging strategies for managing differentiated thyroid cancers refractory to radioiodine

Efficient treatment of radio refractory thyroid cancer is still a major challenge. The recent identification of genetic and epigenetic alterations present in almost all differentiated tumors has revealed novel molecular targets, which can hopefully be exploited to create new treatments for these tumors. This review looks briefly at some of the innovative strategies currently being investigated for the treatment the radioiodine-resistant thyroid cancers.

Development of Long-Circulating pH-Sensitive Liposomes to Circumvent Gemcitabine Resistance in Pancreatic Cancer Cells

PURPOSES

To develop pH-sensitive liposomes (PSL) containing a high content of gemcitabine; and to investigate whether drug loading (DL) would alter the in vitro and pharmacokinetic properties.

METHODS

PSL with a high DL were obtained using a modified small-volume incubation method. The DL effects on drug release rate and in vitro cytotoxicity of PSL were evaluated using MIA PaCa-2 pancreatic cancer cells and their pharmacokinetics investigated in rats.

RESULTS

The highest DL of 4.5 ± 0.1% was achieved for gemcitabine in PSL with 145 ± 5 nm diameter. DL did not alter the in vitro release rate from PSL. The IC50 (48 h) of PSL (DL 0.5 and 4.5%) and non pH-sensitive liposomes (NPSL, DL 4.2%) were 1.1 ± 0.1, 0.7 ± 0.1 and 37.0 ± 7.5 μM, respectively. The PSL resulted in a 4.2-fold increase in its elimination half-life (6.2 h) compared to gemcitabine solution (1.4 h) in rats. No significant difference in pharmacokinetic parameters was observed between the two PSL (DL 0.5 and 4.5%).

CONCLUSION

The PSL offered advantages over NPSL in restoring the sensitivity of pancreatic cancer cells to gemcitabine without requiring a high DL. DL in the PSL did not alter release rate, cytotoxicity or their long-circulating properties. Graphical Abstract ᅟ.