[Show abstract][Hide abstract] ABSTRACT: Aims:
Several anti-tumour properties have been ascribed to the tissue inhibitor of matrix metalloproteinases-3 (TIMP3) gene, including inhibition of neovascularisation in tumour xenografts. Reduced protein expression has been linked to promoter hypermethylation and allelic loss of heterozygosity in various human malignancies. In melanoma-positive lymph nodes from patients, we evaluated the association between TIMP3 expression, vessel density, macrophage infiltration and potential correlations with disease-free survival (DFS) and overall survival (OS).
Patients and methods:
TIMP3 expression was analysed by immunohistochemistry (IHC) in melanoma lymph node biopsies of stage III melanoma patients (n = 43). Blood vessel density and macrophage infiltration were quantitatively assessed and correlation with TIMP3 expression was investigated. Methylation status of the gene promoter was determined using methylation-specific polymerase chain reaction (MSP). Protein expression and promoter methylation status were investigated for associations with DFS and OS.
Reduced expression of TIMP3, as determined by IHC, was observed in 74% of the cases (32 in 43). A significant inverse correlation was observed between TIMP3 expression and vessel density (p = 0.031). Correlation between TIMP3 expression and macrophage infiltration was not statistically significant (p = 0.369). MSP analysis revealed methylation of the gene promoter in 18% (7 in 38) of the analysed cases. No differences in OS and DFS were observed between cases with high and low TIMP3 expression. Gene promoter methylation was significantly associated with both poor 5-year DFS (p = 0.024) and OS (p = 0.034).
Our data indicate that TIMP3 is a dominant negative regulator of angiogenesis in cutaneous melanoma and gene silencing by promoter methylation is associated with poor outcome.
Full-text · Article · Jan 2016 · European journal of cancer (Oxford, England: 1990)
[Show abstract][Hide abstract] ABSTRACT: In numerous studies, thermosensitive liposomes (TSLs) for local heat-triggered delivery of Doxorubicin (Dox) to tumors have been investigated, with TSLs having different lipid formulations, drug loading methodology and testing procedures. To gain more insight in these parameters, we investigated TSLs with four variable DSPC-DPPC lipid ratios (50, 60, 70 or 80% DPPC and 5 mol% of DSPE-PEG2000) using either ammonium sulfate or a citrate buffer for Dox loading. Ammonium sulfate loading of Dox yielded more stable TSLs than citrate loading. At 37 °C, leakage was unnoticeable for all ammonium sulfate TSLs. At 42 °C, complete release occurred within seconds, except for 50% DPPC TSLs, where slow and incomplete release was observed in vitro but also in vivo using a dorsal skinfold window chamber. In contrast to in vitro assays, blood kinetics studies indicated a burst release of Dox upon injection and higher leakage for all TSLs. In therapeutic studies, hyperthermia in combination with TSLs repressed BFS-1 sarcoma growth. Our study shows that prediction of therapeutic efficacy purely based on differences found in vitro is difficult, instead, parameters obtained from pharmacokinetic studies in vivo, and the exact timing of the delivery protocol need to be taken into account.
[Show abstract][Hide abstract] ABSTRACT: Drug delivery through thermosensitive liposomes (TSL) in combination with hyperthermia (HT) has shown great potential. HT can be applied locally forcing TSL to release their content in the heated tumor resulting in high peak concentrations. To perform optimally the drug is ideally released fast (seconds) and taken up rapidly by tumor cells. The aim of this study was to develop a novel thermosensitive liposome formulation of the anthracycline idarubicin (IDA-TSL). The hydrophobicity of idarubicin may improve its release from liposomes and subsequently rapid cellular uptake when combined mild hyperthermia. Here, we investigated a series of parameters to optimize IDA-TSL formulation. The results show that the optimal formulation for IDA-TSL is DPPC/DSPC/DSPE-PEG (6/3.5/0.5mol%), with ammonium EDTA of 6.5 pH as loading buffer and a size of ~85nm. In vitro studies demonstrated minimal leakage of ~20% in FCS at 37°C for 1h, while an ultrafast and complete triggered release of IDA was observed at 42°C. On tumor cells IDA-TSL showed comparable cytotoxicity to free IDA at 42°C, but low cytotoxicity at 37°C. Intravital microscopy imaging demonstrated an efficient in vivo intravascular triggered drug release of IDA-TSL under mild hyperthermia, and a subsequent massive IDA uptake by tumor cells. In animal efficacy studies, IDA-TSL plus mild HT demonstrated prominent tumor growth inhibition and superior survival rate over free IDA with HT or a clinically used Doxil treatment. These results suggest beneficial potential of IDA-TSL combined with local mild HT.
No preview · Article · Nov 2015 · Journal of Controlled Release
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To evaluate pharmacokinetic profile, biodistribution and therapeutic effect of cationic thermosensitive liposomes (CTSL) encapsulating doxorubicin (Dox) upon mild hyperthermia (HT).
Non-targeted thermosensitive liposomes (TSL) and CTSL were developed, loaded with Dox and characterized. Blood kinetics and biodistribution of Dox-TSL and Dox-CTSL were followed in B16BL6 tumor bearing mice upon normothermia (NT) or initial hyperthermia conditions. Efficacy study in B16BL6 tumor bearing mice was followed with Dox-TSL or Dox-CTSL upon NT or HT. Efficacy study in LLC tumor bearing mice was performed upon two HT conditions. Intravital microscopy was performed on B16BL6 tumors implanted in dorsal-skin fold window-bearing mice.
Targeting did not cause faster blood clearance of CTSL compared to TSL. Highest uptake of liposomes was observed in spleen, kidneys and liver. Applying HT prior to CTSL administration increased drug delivery to the tumor and CTSL delivered ~1.7 fold higher Dox concentration compared to TSL. Efficacy in B16BL6 murine melanoma showed that HT had a significant effect on CTSL in tumor suppression and prolonged survival. Efficacy in LLC Lewis lung carcinoma tumor model demonstrates that two HT treatments hold promises for a successful treatment option.
CTSL have potency to increase drug efficacy in tumors due to their targeted and drug release functions.
Preview · Article · Oct 2015 · Pharmaceutical Research
[Show abstract][Hide abstract] ABSTRACT: Liposomes containing cytotoxic agents and targeted with Arg-Gly-Asp based peptides have frequently been used against αvβ3 integrin on tumor neovasculature. However, like many other ligand modified liposomes these preparations suffered from enhanced uptake by the reticulo endothelial system (RES) and off-targeted interaction with integrin receptors vastly expressed in normal organs causing poor biodistribution and toxic effects. Here we mainly focus on development of a RGD-modified liposomal delivery system to enhance both targeting selectivity and tumor uptake. First, sterically stabilized liposomal doxorubicin (SSLD) prepared and decorated with cRGDfK and RGDyC peptides differ in their physical properties. Stability assessments as well as in vitro and in vivo studies revealed that increasing the peptide hydrophobicity promotes the therapeutic efficacy of RGD-SSLD in a C-26 tumor model due to decreased recognition by RES and opsonization and limited off-targeted interactions. Then a novel N-methylated RGD peptide was designed and its capability in targeting integrin presenting cells was comprehensively assessed both in vitro and in vivo. RGDf[N-methyl]C promotes the liposome internalization by HUVEC via integrin mediated endocytosis. Intravital microscopy in window chamber bearing mice illustrated the capability of RGDf[N-methyl]C-liposomes in targeting both tumor vasculature and tumor cells in murine B16F0 and human BLM tumor models. Quantitative biodistribution in mice bearing B16F0 tumor revealed its high affinity to tumor with no considerable affinity to normal organs. Treatment by high dose of RGDf[N-methyl]C-SSLD was found more effective than non-targeted SSLD and no toxic side effect was observed. In conclusion, the RGDf[N-methyl]C-liposome was found promising in targeting tumor vasculature as well as other cells inside the tumor.
No preview · Article · Oct 2015 · Journal of Controlled Release
[Show abstract][Hide abstract] ABSTRACT: To develop RGD-targeted thermosensitive liposomes with increased tumor retention, improving drug release efficiency upon mild hyperthermia (HT) in both tumor and angiogenic endothelial cells.
Standard termosensitive liposomes (TSL) and TSL containing a cyclic Arg-Gly-Asp (cRGD) pentapeptide with the sequence Arg-Cys-D-Phe-Asp-Gly (RGDf[N-Met]C) were synthetized, loaded with Dox and characterized. Temperature- and time-dependent drug release profiles were assessed by fluorometry. Intracellular Dox delivery was studied by flow cytometry and confocal microscopy. Cytotoxic effect of TSL and RGD-TSL was studied on B16Bl6 melanoma, B16F10 melanoma and HUVEC. Intravital microscopy was performed on B16Bl6 tumors implanted in dorsal-skin fold window-bearing mice. Pharmacokinetic and biodistribution of Dox-TSL and Dox-RGD-TSL were followed in B16Bl6 tumor bearing mice upon normothermia or initial hyperthermia conditions.
DLS and cryo-TEM revealed particle homogeneity and size of around 85 nm. Doxorubicin loading efficiency was >95%as assessed by spectrofluorometry. Flow cytometry and confocal microscopy showed a specific uptake of RGD-TSL by melanoma and endothelial cells when compared to TSL and an increased doxorubicin delivery. High resolution intravital microscopy demonstrated specific accumulation of RGD-TSL to the tumor vasculature. Moreover, application of hyperthermia resulted in massive drug release from RGD-TSL. Biodistribution studies showed that initial hyperthermia increases Dox uptake in tumors from TSL and RGD-TSL.
RGD-TSL have potency to increase drug efficacy due to higher uptake by tumor and angiogenic endothelial cells in combination with heat-triggered drug release.
Preview · Article · Jul 2015 · Pharmaceutical Research
[Show abstract][Hide abstract] ABSTRACT: Cell migration is a key feature of virtually every biological process, and it can be studied in a variety of ways. Here we outline a protocol for the in vitro study of cell migration using a ring barrier-based assay. A 'barrier' is inserted in the culture chamber, which prevents cells from entering a defined area. Cells of interest are seeded around this barrier, and after the formation of a peripheral monolayer the barrier is removed and migration into the cell-free area is monitored. This assay is highly reproducible and convenient to perform, and it allows the deduction of several parameters of migration, including total and effective migration, velocity and cell polarization. An advantage of this assay over the conventional scratch assay is that the cells move over an unaltered and virgin surface, and thus the effect of matrix components on cell migration can be studied. In addition, the cells are not harmed at the onset of the assay. Through computer automation, four individual barrier assays can be monitored at the same time. The procedure can be used in a 12-well standard plate allowing higher throughput, or it can be modified to perform invasion assays. The basic procedure takes 2-3 d to complete.
[Show abstract][Hide abstract] ABSTRACT: Phosphatases have long been regarded as tumor suppressors, however there is emerging evidence for a tumor initiating role for some phosphatases in several forms of cancer. Low Molecular Weight Protein Tyrosine Phosphatase (LMWPTP; acid phosphatase 1 [ACP1]) is an 18 kDa enzyme that influences the phosphorylation of signaling pathway mediators involved in cancer and is thus postulated to be a tumor-promoting enzyme, but neither unequivocal clinical evidence nor convincing mechanistic actions for a role of LMWPTP have been identified. In the present study, we show that LMWPTP expression is not only significantly increased in colorectal cancer (CRC), but also follows a step-wise increase in different levels of dysplasia. Chemical inhibition of LMWPTP significantly reduces CRC growth. Furthermore, downregulation of LMWPTP in CRC leads to a reduced migration ability in both 2D- and 3D-migration assays, and sensitizes tumor cells to the chemotherapeutic agent 5-FU. In conclusion, this study shows that LMWPTP is not only overexpressed in colorectal cancer, but it is correlated with the malignant potential of this cancer, suggesting that this phosphatase may act as a predictive biomaker of CRC stage and represents a rational novel target in the treatment of this disease.
[Show abstract][Hide abstract] ABSTRACT: Further understanding of the molecular biology and pathogenesis of hepatocellular carcinoma (HCC) is crucial for future therapeutic development. SMAD4, recognized as an important tumor suppressor, is a central mediator of transforming growth factor beta (TGFB) and bone morphogenetic protein (BMP) signaling. This study investigated the role of SMAD4 in HCC. Nuclear localization of SMAD4 was observed in a cohort of 140 HCC patients using tissue microarray. HCC cell lines were used for functional assay in vitro and in immune-deficient mice. Nuclear SMAD4 levels were significantly increased in patient HCC tumors as compared with adjacent tissues. Knockdown of SMAD4 significantly reduced the efficiency of colony formation and migratory capacity of HCC cells in vitro and was incompatible with HCC tumor initiation and growth in mice. Knockdown of SMAD4 partially conferred resistance to the anti-growth effects of BMP ligand in HCC cells. Importantly, simultaneous elevation of SMAD4 and phosphorylated SMAD2/3 is significantly associated with poor patient outcome after surgery. Although high levels of SMAD4 can also mediate an antitumor function by coupling with phosphorylated SMAD1/5/8, this signaling, however, is absent in majority of our HCC patients. In conclusion, this study revealed a highly non-canonical tumor-promoting function of SMAD4 in HCC. The drastic elevation of nuclear SMAD4 in sub-population of HCC tumors highlights its potential as an outcome predictor for patient stratification and a target for personalized therapeutic development.Oncogene advance online publication, 22 December 2014; doi:10.1038/onc.2014.425.
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To improve therapeutic activity of mitoxantrone (MTO)-based chemotherapy by reducing toxicity through encapsulation in nanoliposomes and enhancing intracellular drug delivery using short-chain sphingolipid (SCS) mediated tumor cell membrane permeabilization.
Standard (MTOL) and nanoliposomes enriched with the SCS, C8-Glucosylceramide or C8-Galactosylceramide (SCS-MTOL) were loaded by a transmembrane ammonium sulphate gradient and characterized by DLS and cryo-TEM. Intracellular MTO delivery was measured by flow cytometry and imaged by fluorescence microscopy. In vitro cytotoxicity was studied in breast carcinoma cell lines. Additionally, live cell confocal microscopy addressed the drug delivery mechanism by following the intracellular fate of the nanoliposomes, the SCS and MTO. Intratumoral MTO localization in relation to CD31-positive tumor vessels and CD11b positive cells was studied in an orthotopic MCF-7 breast cancer xenograft.
Stable SCS-MTOL were developed increasing MTO delivery and cytotoxicity to tumor cells compared to standard MTOL. This effect was much less pronounced in normal cells. The drug delivery mechanism involved a transfer of SCS to the cell membrane, independently of drug transfer and not involving nanoliposome internalization. MTO was detected intratumorally upon MTOL and SCS-MTOL treatment, but not after free MTO, suggesting an important improvement in tumor drug delivery by nanoliposomal formulation. Nanoliposomal MTO delivery and cellular uptake was heterogeneous throughout the tumor and clearly correlated with CD31-positive tumor vessels. Yet, MTO uptake by CD11b positive cells in tumor stroma was minor.
Nanoliposomal encapsulation improves intratumoral MTO delivery over free drug. Liposome bilayer-incorporated SCS preferentially permeabilize tumor cell membranes enhancing intracellular MTO delivery.
Full-text · Article · Oct 2014 · Pharmaceutical Research
[Show abstract][Hide abstract] ABSTRACT: Liposomal nanoparticles can circumvent toxicity of encapsulated chemotherapeutic drugs, but fall short in tumor-specific and efficient intracellular drug delivery. To overcome these shortcomings, we designed a multifunctional dual targeted, heat-responsive nanocarrier encapsulating doxorubicin (Dox) as a chemotherapeutic content. Dox-loaded cationic thermosensitive liposomes (Dox-CTSL) carry targeting functions addressing tumor cells and tumor vasculature and have a heat-responsive lipid bilayer. Targeted Dox-CTSL demonstrated superior uptake by and toxicity to different tumor cell lines and endothelial cells compared to non-targeted TSL. Heat triggered intracellular Dox release in acidic cell compartments was visualized as fluorescent Dox nanobursts by live cell confocal microscopy. In vivo, using high resolution intravital microscopy, we demonstrated that Dox-CTSL upon an external heat-trigger delivered 3-fold higher Dox quantity to tumors than TSL. Dox-CTSL bound specifically to tumor vasculature, which in combination with the heat-triggered drug release caused significant tumor vessel damage, which was not observed when non-targeted TSL were administered. Therefore, Dox-CTSL have strong potency to increase drug efficacy due to targeted delivery and heat-triggered drug release in tumors.
Full-text · Article · Aug 2014 · Journal of Controlled Release
[Show abstract][Hide abstract] ABSTRACT: Photodynamic therapy (PDT) is an established treatment modality, used mainly for anticancer therapy that relies on the interaction of photosensitizer, light and oxygen. For the treatment of pathologies in certain anatomical sites, improved targeting of the photosensitizer is necessary to prevent damage to healthy tissue. We report on a novel dual approach of targeted PDT (vascular and cellular targeting) utilizing the expression of neuropeptide somatostatin receptor (sst2) on tumor and neovascular-endothelial cells. We synthesized two conjugates containing the somatostatin analogue [Tyr3]-octreotate and Chlorin e6 (Ce6): Ce6-K3-[Tyr3]-octreotate (1) and Ce6-[Tyr3]-octreotate-K3-[Tyr3]-octreotate (2). Investigation of the uptake and photodynamic activity of conjugates in-vitro in human erythroleukemic K562 cells showed that conjugation of [Tyr3]-octreotate with Ce6 in conjugate 1 enhances uptake (by a factor 2) in cells over-expressing sst2 compared to wild-type cells. Co-treatment with excess free Octreotide abrogated the phototoxicity of conjugate 1 indicative of a specific sst2-mediated effect. In contrast conjugate 2 showed no receptor-mediated effect due to its high hydrophobicity. When compared with un-conjugated Ce6, the PDT activity of conjugate 1 was lower. However, it showed higher photostability which may compensate for its lower phototoxicity. Intra-vital fluorescence pharmacokinetic studies of conjugate 1 in rat skin-fold observation chambers transplanted with sst2+ AR42J acinar pancreas tumors showed significantly different uptake profiles compared to free Ce6. Co-treatment with free Octreotide significantly reduced conjugate uptake in tumor tissue (by a factor 4) as well as in the chamber neo-vasculature. These results show that conjugate 1 might have potential as an in-vivo sst2 targeting photosensitizer conjugate.
[Show abstract][Hide abstract] ABSTRACT: Aims:
With the aim to improve peptide receptor radionuclide therapy effects in patients with gastroenteropancreatic neuroendocrine tumor (GEPNET) liver metastases we explored the effect of intra-arterial (IA) administration of [(111)In-DTPA]octreotide ((111)In-DTPAOC) on tumor uptake in an animal model and in a patient study.
Preclinical study: After administering (111)In-DTPAOC intra-venously (IV) or IA, biodistribution studies were performed in rats with a hepatic somatostatin receptor subtype 2 (sst2)-positive tumor. Clinical study: 3 patients with neuroendocrine liver metastases were injected twice with (111)In-DTPAOC. The first injection was given IV, and 2 weeks later, the second was injected IA (hepatic artery). Planar images of the abdomen were made up to 72 hours after injection. Blood samples were taken and urine was collected. Pharmacokinetic modeling was performed on the IV and IA data of the same patient. Based on this model, additional (177)Lu dosimetry calculations for IV and IA administrations were performed.
The preclinical study showed a two-fold higher (111)In-DTPAOC tumor uptake after IA administration than after IV injection. Patient data showed a large variability in radioactivity increment in liver metastases after IA administration compared with IV administration. Renal radioactivity was not significantly lower after IA administration; (177)Lu dosimetry simulations in 1 patient using a maximum kidney radiation dose of 23 Gy showed IA administration resulted in a mean increase in tumor radiation dose of 2.9-fold.
Preclinical and clinical data both indicate that IA administration of radiolabeled somatostatin analogs via the hepatic artery can significantly increase radionuclide uptake in GEPNET, sst2-positive, liver metastases up to 72 hours postinjection, although the effect of IA administration can differ between patients.
No preview · Article · May 2014 · Cancer Biotherapy & Radiopharmaceuticals
[Show abstract][Hide abstract] ABSTRACT: The use of monoclonal antibodies (mAbs) as therapeutic tools has increased dramatically in the last decade and is now one of the mainstream strategies to treat cancer. Nonetheless, it is still not completely understood how mAbs mediate tumor cell elimination or the effector cells that are involved. Using intravital microscopy, we found that antibody-dependent phagocytosis (ADPh) by macrophages is a prominent mechanism for removal of tumor cells from the circulation in a murine tumor cell opsonization model. Tumor cells were rapidly recognized and arrested by liver macrophages (Kupffer cells). In the absence of mAbs, Kupffer cells sampled tumor cells; however, this sampling was not sufficient for elimination. By contrast, antitumor mAb treatment resulted in rapid phagocytosis of tumor cells by Kupffer cells that was dependent on the high-affinity IgG-binding Fc receptor (FcγRI) and the low-affinity IgG-binding Fc receptor (FcγRIV). Uptake and intracellular degradation were independent of reactive oxygen or nitrogen species production. Importantly, ADPh prevented the development of liver metastases. Tumor cell capture and therapeutic efficacy were lost after Kupffer cell depletion. Our data indicate that macrophages play a prominent role in mAb-mediated eradication of tumor cells. These findings may help to optimize mAb therapeutic strategies for patients with cancer by helping us to aim to enhance macrophage recruitment and activity.
Full-text · Article · Jan 2014 · The Journal of clinical investigation
[Show abstract][Hide abstract] ABSTRACT: Liposomal chemotherapy brings the advantage of minimizing systemic toxicity towards healthy organs and tissues, while has the drawbacks of limited nanoparticle accumulation and low drug bioavailability at targeted tumors. The aim of our study is to apply a clinically available mild hyperthermia (HT) treatment with thermosensitive liposomes (TSL) to tackle both issues A two-step HT approach was combined with systemic administration of doxorubicin (Dox) TSL, in a first step to maximize nanoparticle accumulation in tumors and second step to actively trigger Dox release. The therapeutic activity of the two-step approach was compared to a one-step HT triggering intravascular Dox release from circulating TSL. Whereas the intravascular drug release approach requires fast releasing Dox-TSL (Dox-fTSL), the TSL formulation used in the two-step approach is fine-tuned to prolong Dox retention at physiological temperature in circulation, while releasing their drug content at mild HT at a slower rate (Dox-sTSL). Cytotoxicity assays show that a first-step HT at 41°C for 1hour causes no drug resistance on murine BFS-1 sarcoma, human BLM melanoma cell lines and Human Umbilical Vein Endothelial Cells (HUVEC) towards subsequent exposure to Dox. However, HT sensitizes HUVEC towards Dox at higher concentrations (10-100μM). After 2hours of intratumoral Dox-TSL accumulation, HT at 42°C for 1hour was applied to trigger Dox release from Dox-sTSL. Quantification of intratumoral Dox accumulation revealed that the two-step HT approach increased TSL accumulation and Dox bioavailability reaching levels comparable to the intravascular release approach. The two-step HT in combination with Dox-sTSL delayed tumor growth for 12days compared to PBS group, however, was less effective compared to intravascular Dox release from Dox-fTSL using one-step HT. The two-step approach focuses on interstitial drug release upon mild HT, instead of intravascular drug release. This novel two-step approach represents an attractive alternative for the treatment of large and deep seated tumors, which are difficult to heat precisely and require loco-regional HT of the tumor area and accumulated Dox-sTSL therein to obtain a precise intratumoral drug delivery.
No preview · Article · Nov 2013 · Journal of Controlled Release