Anti-metastatic effects of liposomal gemcitabine in a human orthotopic LNCaP prostate cancer xenograft model

Cancer metastasis to the bone: Mechanisms and animal models (Review)

The majority of cancer-related deaths result from tumor metastasis, with bone metastasis occurring in almost all types of malignant tumors. Understanding the mechanism by which tumors metastasize to bone is critical for the identification of novel therapeutic targets. A large amount of research has been carried out using animal models, and these models have been crucial in advancing the fundamental understanding of cancer. However, current models are limited; although they can mimic specific stages of the metastatic process, they are not able to replicate the entire process from tumorigenesis to bone metastasis. The present review describes the molecular changes that occur in the intraosseous microenvironment of bone metastases, including osteolytic and osteoblastic types, and summarizes advancements in animal models of bone metastasis.

Mapping global research landscape and trend of nano-drug delivery system for urological cancers: a bibliometric analysis

Aim: We conducted a bibliometric analysis to quantitatively study the development pathway, research hotspots and evolutionary trends of nano-drug delivery systems (NDDS) in treating urological tumors.Materials & methods: We used the Web of Science Core Collection to retrieve the literature related to NDDS in the urological tumors up to November 1, 2023. Bibliometric analysis and visualization were conducted using CiteSpace, VOSviewer and R-Bibliometrix. The major aspects of analysis included contributions from different countries/regions, authors' contributions, keywords identification, citation frequencies and overall research trends.Results: We included 3,220 articles. The analysis of annual publication trends revealed significant growth in this field since 2010, which has continued to the present day. The United States and China have far exceeded other countries/regions in the publication volume of papers in this field. The progression of the shell structure of NDDS in the urinary system has gradually transitioned from non-biological materials to biocompatible materials and ultimately to completely biocompatible materials. Mucoadhesive NDDS for intravesical drug delivery is a hotspot and a potential research material for bladder cancer.Conclusion: The field of NDDS in urological tumors has emerged as a research hotspot. Future research should focus on synergistic effects of NDDS with other treatment modalities.

Discovery of , a First-in-Class and Orally Bioavailable PROTAC Degrader of the Androgen Receptor Targeting N-Terminal Domain for the Treatment of Prostate Cancer

We report small molecular PROTAC compounds targeting the androgen receptor N-terminal domain (AR-NTD), which were obtained by tethering AR-NTD antagonists and different classes of E3 ligase ligands through chemical linkers. A representative compound, BWA-522, effectively induces degradation of both AR-FL and AR-V7 and is more potent than the corresponding antagonist against prostate cancer (PC) cells in vitro. We have shown that the degradation of AR-FL and AR-V7 proteins by BWA-522 can suppress the expression of AR downstream proteins and induce PC cell apoptosis. BWA-522 achieves 40.5% oral bioavailability in mice and 69.3% in beagle dogs. In a LNCaP xenograft model study, BWA-522 was also proved to be an efficacious PROTAC degrader, resulting in 76% tumor growth inhibition after oral administration of a dose of 60 mg/kg. This study indicates that BWA-522 is a promising AR-NTD PROTAC for the treatment of AR-FL- and AR-V7-dependent tumors.

Nanotherapeutic Approach to Delivery of Chemo- and Gene Therapy for Organ-Confined and Advanced Castration-Resistant Prostate Cancer

Treatments for late-stage prostate cancer (CaP) have not been very successful. Frequently, advanced CaP progresses to castration-resistant prostate cancer (CRPC), with 50#37;-70% of patients developing bone metastases. CaP with bone metastasis-associated clinical complications and treatment resistance presents major clinical challenges. Recent advances in the formulation of clinically applicable nanoparticles (NPs) have attracted attention in the fields of medicine and pharmacology with applications to cancer and infectious and neurological diseases. NPs have been rendered biocompatible, pose little to no toxicity to healthy cells and tissues, and are engineered to carry large therapeutic payloads, including chemo- and genetic therapies. Additionally, if required, targeting specificity can be achieved by chemically coupling aptamers, unique peptide ligands, or monoclonal antibodies to the surface of NPs. Encapsulating toxic drugs within NPs and delivering them specifically to their cellular targets overcomes the problem of systemic toxicity. Encapsulating highly labile genetic therapeutics such as RNA within NPs provides a protective environment for the payload during parenteral administration. The loading efficiencies of NPs have been maximized while the controlled their therapeutic cargos has been released. Theranostic ("treat and see") NPs have developed combining therapy with imaging capabilities to provide real-time, image-guided monitoring of the delivery of their therapeutic payloads. All of these NP accomplishments have been applied to the nanotherapy of late-stage CaP, offering a new opportunity for a previously dismal prognosis. This article gives an update on current developments in the use of nanotechnology for treating late-stage, castration-resistant CaP.

Establishment of an orthotopic prostate cancer xenograft mouse model using microscope-guided orthotopic injection of LNCaP cells into the dorsal lobe of the mouse prostate

Background

Orthotopic LNCaP xenograft mouse models closely mimic the progression of androgen-dependent prostate cancer in humans; however, orthotopic injection of LNCaP cells into the mouse prostate remains a challenge.

Methods

Under the guidance of a stereoscopic microscope, the anatomy of the individual prostate lobes in male Balb/c athymic nude mice was investigated, and LNCaP cells were inoculated into the mouse dorsal prostate (DP) to generate orthotopic tumors that mimicked the pathophysiological process of prostate cancer in humans. Real-time ultrasound imaging was used to monitor orthotopic prostate tumorigenesis, contrast-enhanced ultrasonography (CEUS) was used to characterize tumor angiogenesis, and macroscopic and microscopic characteristics of tumors were described.

Results

The DP had a trigonal bipyramid-shape and were located at the base of the seminal vesicles. After orthotopic inoculation, gray scale ultrasound imaging showed progressive changes in tumor echotexture, shape and location, and tumors tended to protrude into the bladder. After 8 weeks, the tumor take rate was 65% (n = 13/20 mice). On CEUS, signal intensity increased rapidly, peaked, and decreased gradually. Observations of gross specimens showed orthotopic prostate tumors were well circumscribed, round, dark brown, and soft, with a smooth outer surface and a glossy appearance. Microscopically, tumor cells were arranged in acini encircled by fibrous septa with variably thickened walls, mimicking human adenocarcinoma.

Conclusions

This study describes a successful approach to establishing an orthotopic LNCaP xenograft Balb/c athymic nude mouse model. The model requires a thorough understanding of mouse prostate anatomy and proper technique. The model represents a valuable tool for the in vivo study of the biological processes involved in angiogenesis in prostate cancer and preclinical evaluations of novel anti-angiogenic therapies.

Autophagy provides a conceptual therapeutic framework for bone metastasis from prostate cancer

Prostate cancer is a common malignant tumor, which can spread to multiple organs in the body. Metastatic disease is the dominant reason of death for patients with prostate cancer. Prostate cancer usually transfers to bone. Bone metastases are related to pathologic fracture, pain, and reduced survival. There are many known targets for prostate cancer treatment, including androgen receptor (AR) axis, but drug resistance and metastasis eventually develop in advanced disease, suggesting the necessity to better understand the resistance mechanisms and consider multi-target medical treatment. Because of the limitations of approved treatments, further research into other potential targets is necessary. Metastasis is an important marker of cancer development, involving numerous factors, such as AKT, EMT, ECM, tumor angiogenesis, the development of inflammatory tumor microenvironment, and defect in programmed cell death. In tumor metastasis, programmed cell death (autophagy, apoptosis, and necroptosis) plays a key role. Malignant cancer cells have to overcome the different forms of cell death to transfer. The article sums up the recent studies on the mechanism of bone metastasis involving key regulatory factors such as macrophages and AKT and further discusses as to how regulating autophagy is crucial in relieving prostate cancer bone metastasis.

Nanovectorization of Prostate Cancer Treatment Strategies: A New Approach to Improved Outcomes

Prostate cancer (PC) is the most frequent male cancer in the Western world. Progression to Castration Resistant Prostate Cancer (CRPC) is a known consequence of androgen withdrawal therapy, making CRPC an end-stage disease. Combination of cytotoxic drugs and hormonal therapy/or genotherapy is a recognized modality for the treatment of advanced PC. However, this strategy is limited by poor bio-accessibility of the chemotherapy to tumor sites, resulting in an increased rate of collateral toxicity and incidence of multidrug resistance (MDR). Nanovectorization of these strategies has evolved to an effective approach to efficacious therapeutic outcomes. It offers the possibility to consolidate their antitumor activity through enhanced specific and less toxic active or passive targeting mechanisms, as well as enabling diagnostic imaging through theranostics. While studies on nanomedicine are common in other cancer types, only a few have focused on prostate cancer. This review provides an in-depth knowledge of the principles of nanotherapeutics and nanotheranostics, and how the application of this rapidly evolving technology can clinically impact CRPC treatment. With particular reference to respective nanovectors, we draw clinical and preclinical evidence, demonstrating the potentials and prospects of homing nanovectorization into CRPC treatment strategies.

Mouse-Derived Isograft (MDI) In Vivo Tumor Models I. Spontaneous sMDI Models: Characterization and Cancer Therapeutic Approaches

Syngeneic in vivo tumor models are valuable for the development and investigation of immune-modulating anti-cancer drugs. In the present study, we established a novel syngeneic in vivo model type named mouse-derived isografts (MDIs). Spontaneous MDIs (sMDIs) were obtained during a long-term observation period (more than one to two years) of naïve and untreated animals of various mouse strains (C3H/HeJ, CBA/J, DBA/2N, BALB/c, and C57BL/6N). Primary tumors or suspicious tissues were assessed macroscopically and re-transplanted in a PDX-like manner as small tumor pieces into sex-matched syngeneic animals. Nine outgrowing primary tumors were histologically characterized either as adenocarcinomas, histiocytic carcinomas, or lymphomas. Growth of the tumor pieces after re-transplantation displayed model heterogeneity. The adenocarcinoma sMDI model JA-0009 was further characterized by flow cytometry, RNA-sequencing, and efficacy studies. M2 macrophages were found to be the main tumor infiltrating leukocyte population, whereas only a few T cells were observed. JA-0009 showed limited sensitivity when treated with antibodies against inhibitory checkpoint molecules (anti-mPD-1 and anti-mCTLA-4), but high sensitivity to gemcitabine treatment. The generated sMDI are spontaneously occurring tumors of low passage number, propagated as tissue pieces in mice without any tissue culturing, and thus conserving the original tumor characteristics and intratumoral immune cell populations.

Preclinical imaging and translational animal models of cancer for accelerated clinical implementation of nanotechnologies and macromolecular agents

The majority of animal models of cancer have performed poorly in terms of predicting clinical performance of new therapeutics, which are most often first evaluated in patients with advanced, metastatic disease. The development and use of metastatic models of cancer may enhance clinical translatability of preclinical studies focused on the development of nanotechnology-based drug delivery systems and macromolecular therapeutics, potentially accelerating their clinical implementation. It is recognized that the development and use of such models are not without challenge. Preclinical imaging tools offer a solution by allowing temporal and spatial characterization of metastatic lesions. This paper provides a review of imaging methods applicable for evaluation of novel therapeutics in clinically relevant models of advanced cancer. An overview of currently utilized models of oncology in small animals is followed by image-based development and characterization of visceral metastatic cancer models. Examples of imaging tools employed for metastatic lesion detection, evaluation of anti-tumor and anti-metastatic potential and biodistribution of novel therapies, as well as the co-development and/or use of imageable surrogates of response, are also discussed. While the focus is on development of macromolecular and nanotechnology-based therapeutics, examples with small molecules are included in some cases to illustrate concepts and approaches that can be applied in the assessment of nanotechnologies or macromolecules.

Liposomal delivery of dexamethasone attenuates prostate cancer bone metastatic tumor growth in vivo

BACKGROUND

The inflammatory tumor microenvironment, and more specifically the tumor-associated macrophages, plays an essential role in the development and progression of prostate cancer towards metastatic bone disease. Tumors are often characterized by a leaky vasculature, which - combined with the prolonged circulation kinetics of liposomes - leads to efficient tumor localization of these drug carriers, via the so-called enhanced permeability and retention (EPR) -effect. In this study, we evaluated the utility of targeted, liposomal drug delivery of the glucocorticoid dexamethasone in a model of prostate cancer bone metastases.

METHODS

Tumor-bearing Balb-c nu/nu mice were treated intravenously with 0.2-1.0-5.0 mg/kg/week free- and liposomal DEX for 3-4 weeks and tumor growth was monitored by bioluminescent imaging.

RESULTS

Intravenously administered liposomes localize efficiently to bone metastases in vivo and treatment of established bone metastases with (liposomal) dexamethasone resulted in a significant inhibition of tumor growth up to 26 days after initiation of treatment. Furthermore, 1.0 mg/kg liposomal dexamethasone significantly outperformed 1.0 mg/kg free dexamethasone, and was found to be well-tolerated at clinically-relevant dosages that display potent anti-tumor efficacy.

CONCLUSIONS

Liposomal delivery of the glucocorticoid dexamethasone inhibits the growth of malignant bone lesions. We believe that liposomal encapsulation of dexamethasone offers a promising new treatment option for advanced, metastatic prostate cancer which supports further clinical evaluation.

Trimethoxy-resveratrol and piceatannol administered orally suppress and inhibit tumor formation and growth in prostate cancer xenografts

BACKGROUND

Resveratrol (Res) is recognized as a promising cancer chemoprevention dietary polyphenol with antioxidative, anti-inflammatory, and anticancer properties. However, the role of its analogues in prostate cancer (PCa) chemoprevention is unknown.

METHODS

We synthesized several natural and synthetic analogues of Res and characterized their effects on PCa cells in vitro using a cell proliferation assay. A colony formation assay and in vitro validation of luciferase (Luc) activity was done for LNCaP-Luc cells that were consequently used for in vivo studies. The efficacy of Res, trimethoxy-resveratrol (3M-Res) and piceatannol (PIC) was studied in a subcutaneous (s.c.) model of PCa using oral gavage. Tumor progression was monitored by traditional caliper and bioluminescent imaging. The levels of cytokines in serum were examined by ELISA, and the levels of compounds in serum and tumor tissues were determined by gas chromatography-mass spectrometry.

RESULTS

We examined the anti-proliferative activities of Res/analogues in three PCa cell lines. We further compared the chemopreventive effects of oral Res, 3M-Res, and PIC in LNCaP-Luc-xenografts. We found that 2 weeks pretreatment with the compounds diminished cell colonization, reduced tumor volume, and decreased tumor growth in the xenografts. Both 3M-Res and PIC demonstrated higher potency in inhibiting tumor progression compared to Res. Notably, 3M-Res was the most active in inhibiting cell proliferation and suppressing colony formation, and its accumulation in both serum and tumor tissues was the highest.

CONCLUSIONS

Our findings offer strong pre-clinical evidence for the utilization of dietary stilbenes, particularly 3M-Res, as novel, potent, effective chemopreventive agents in PCa.

Hyaluronic acid-coated liposomes for active targeting of gemcitabine

The aim of this work was the preparation, characterization, and preliminary evaluation of the targeting ability toward pancreatic adenocarcinoma cells of liposomes containing the gemcitabine lipophilic prodrug [4-(N)-lauroyl-gemcitabine, C12GEM]. Hyaluronic acid (HA) was selected as targeting agent since it is biodegradable, biocompatible, and can be chemically modified and its cell surface receptor CD44 is overexpressed on various tumors. For this purpose, conjugates between a phospholipid, the 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), and HA of two different low molecular weights 4800 Da (12 disaccharidic units) and 12,000 Da (32 disaccharidic units), were prepared, characterized, and introduced in the liposomes during the preparation. Different liposomal formulations were prepared and their characteristics were analyzed: size, Z potential, and TEM analyses underline a difference in the HA-liposomes from the non-HA ones. In order to better understand the HA-liposome cellular localization and to evaluate their interaction with CD44 receptor, confocal microscopy studies were performed. The results demonstrate that HA facilitates the recognition of liposomes by MiaPaCa2 cells (CD44(+)) and that the uptake increases with increase in the polymer molecular weight. Finally, the cytotoxicity of the different preparations was evaluated and data show that incorporation of C12GEM increases their cytotoxic activity and that HA-liposomes inhibit cell growth more than plain liposomes. Altogether, the results demonstrate the specificity of C12GEM targeting toward CD44-overexpressing pancreatic adenocarcinoma cell line using HA as a ligand.

Gemcitabine-loaded liposomes: rationale, potentialities and future perspectives

This review describes the strategies used in recent years to improve the biopharmaceutical properties of gemcitabine, a nucleoside analog deoxycytidine antimetabolite characterized by activity against many kinds of tumors, by means of liposomal devices. The main limitation of using this active compound is the rapid inactivation of deoxycytidine deaminase following administration in vivo. Consequently, different strategies based on its encapsulation/complexation in innovative vesicular colloidal carriers have been investigated, with interesting results in terms of increased pharmacological activity, plasma half-life, and tumor localization, in addition to decreased side effects. This review focuses on the specific approaches used, based on the encapsulation of gemcitabine in liposomes, with particular attention to the results obtained during the last 5 years. These approaches represent a valid starting point in the attempt to obtain a novel, commercializable drug formulation as already achieved for liposomal doxorubicin (Doxil^®, Caelyx^®).

Gemcitabine versus Modified Gemcitabine: a review of several promising chemical modifications

Gemcitabine, an anticancer agent which acts against a wide range of solid tumors, is known to be rapidly deaminated in blood to the inactive metabolite 2',2'-difluorodeoxyuridine and to be rapidly excreted by the urine. Moreover, many cancers develop resistance against this drug, such as loss of transporters and kinases responsible for the first phosphorylation step. To increase its therapeutic levels, gemcitabine is administered at high doses (1000 mg/m(2)) causing side effects (neutropenia, nausea, and so forth). To improve its metabolic stability and cytotoxic activity and to limit the phenomena of resistance many alternatives have emerged, such as the synthesis of prodrugs. Modifying an anticancer agent is not new; paclitaxel or ara-C has been subjected to such changes. This review summarizes the various chemical modifications that can be found in the 4-(N)- and 5'-positions of gemcitabine. They can provide (i) a protection against deamination, (ii) a better storage and (iii) a prolonged release in the cell, (iv) a possible use in the case of deoxycytidine kinase deficiency, and (v) transporter deficiency. These new gemcitabine-based sysems have the potential to improve the clinical outcome of a chemotherapy strategy.

Gemcitabine reactivates epigenetically silenced genes and functions as a DNA methyltransferase inhibitor

Gemcitabine is indicated in combination with cisplatin as first-line therapy for solid tumours including non-small cell lung cancer (NSCLC), bladder cancer and mesothelioma. Gemcitabine is an analogue of pyrimidine cytosine and functions as an anti-metabolite. Structurally, however, gemcitabine has similarities to 5-aza-2-deoxycytidine (decitabine/Dacogen®), a DNA methyltransferase inhibitor (DNMTi). NSCLC, mesothelioma and prostate cancer cell lines were treated with decitabine and gemcitabine. Reactivation of epigenetically silenced genes was examined by RT-PCR/qPCR. DNA methyltransferase activity in nuclear extracts and recombinant proteins was measured using a DNA methyl-transferase assay, and alterations in DNA methylation status were examined using methylation-specific PCR (MS-PCR) and pyrosequencing. We observe a reactivation of several epigenetically silenced genes including GSTP1, IGFBP3 and RASSF1A. Gemcitabine functionally inhibited DNA methyltransferase activity in both nuclear extracts and recombinant proteins. Gemcitabine dramatically destabilised DNMT1 protein. However, DNA CpG methylation was for the most part unaffected by gemcitabine. In conclusion, gemcitabine both inhibits and destabilises DNA methyltransferases and reactivates epigenetically silenced genes having activity equivalent to decitabine at concentrations significantly lower than those achieved in the treatment of patients with solid tumours. This property may contribute to the anticancer activity of gemcitabine.

EGFR-targeted stearoyl gemcitabine nanoparticles show enhanced anti-tumor activity

Previously, it was shown that a novel 4-(N)-stearoyl gemcitabine nanoparticle formulation was more effective than gemcitabine hydrochloride in controlling the growth of model mouse or human tumors pre-established in mice. In the present study, the feasibility of targeting the stearoyl gemcitabine nanoparticles (GemC18-NPs) into tumor cells that over-express epidermal growth factor receptor (EGFR) to more effectively control tumor growth was evaluated. EGFR is over-expressed in a variety of tumor cells, and EGF is a known natural ligand of EGFR. Recombinant murine EGF was conjugated onto the GemC18-NPs. The ability of the EGF to target the GemC18-NPs to human breast adenocarcinoma cells that expressed different levels of EGFR was evaluated in vitro and in vivo. In culture, the extent to which the EGF-conjugated GemC18-NPs were taken up by tumor cells was correlated to the EGFR density on the tumor cells, whereas the uptake of untargeted GemC18-NPs exhibited no difference among those same cell lines. The relative cytotoxicity of the EGF-conjugated GemC18-NPs to tumor cells in culture was correlated to EGFR expression as well. In vivo, EGFR-over-expressing MDA-MB-468 tumors in mice treated with the EGF-conjugated GemC18-NPs grew significantly slower than in mice treated with untargeted GemC18-NPs, likely due to that the EGF-GemC18-NPs were more anti-proliferative, anti-angiogenic, and pro-apoptotic. Fluorescence intensity data from ex vivo imaging showed that the EGF on the nanoparticles helped increase the accumulation of the GemC18-NPs into MDA-MB-468 tumors pre-established in mice by more than 2-fold as compared to the un-targeted GemC18-NPs. In conclusion, active targeting of the GemC18-NPs into EGFR-over-expressed tumors can further enhance their anti-tumor activity.

Health effects of dietary phospholipids

Beneficial effects of dietary phospholipids (PLs) have been mentioned since the early 1900's in relation to different illnesses and symptoms, e.g. coronary heart disease, inflammation or cancer. This article gives a summary of the most common therapeutic uses of dietary PLs to provide an overview of their approved and proposed benefits; and to identify further investigational needs.From the majority of the studies it became evident that dietary PLs have a positive impact in several diseases, apparently without severe side effects. Furthermore, they were shown to reduce side effects of some drugs. Both effects can partially be explained by the fact that PL are highly effective in delivering their fatty acid (FA) residues for incorporation into the membranes of cells involved in different diseases, e.g. immune or cancer cells. The altered membrane composition is assumed to have effects on the activity of membrane proteins (e.g. receptors) by affecting the microstructure of membranes and, therefore, the characteristics of the cellular membrane, e.g. of lipid rafts, or by influencing the biosynthesis of FA derived lipid second messengers. However, since the FAs originally bound to the applied PLs are increased in the cellular membrane after their consumption or supplementation, the FA composition of the PL and thus the type of PL is crucial for its effect. Here, we have reviewed the effects of PL from soy, egg yolk, milk and marine sources. Most studies have been performed in vitro or in animals and only limited evidence is available for the benefit of PL supplementation in humans. More research is needed to understand the impact of PL supplementation and confirm its health benefits.

Liposome based delivery systems in pancreatic cancer treatment: from bench to bedside

Despite rapid advances in cancer diagnosis and treatment, pancreatic cancer remains one of the most difficult human malignancies to be treated, with a mortality rate nearly equal to its incidence. Although gemcitabine has been established as the standard first-line treatment for advanced pancreatic cancer, gemcitabine-based combination chemotherapy showed either marginal or no improvement in survival. Developments in liposomal delivery systems have facilitated the targeting of specific agents for cancer treatment. Such systems could be developed as platforms for future multi-functional theranostic nanodevices tailor-made for the combined detection of early cancer and functional drug delivery. We systemically review liposome based drug-delivery systems, which can provide improved pharmacokinetics, reduced side effects and potentially increased tumor uptake, for pancreatic cancer therapy. Novel liposomal formulations allowing for higher tumor targeting efficiencies and used in current clinical trials to treat this challenging disease are emphasized.

Metastasizing, Luciferase Transduced MAT‑Lu Rat Prostate Cancer Models: Follow up of Bolus and Metronomic Therapy with Doxorubicin as Model Drug

The most fatal outcomes of prostate carcinoma (PCa) result from hormone-refractory variants of the tumor, especially from metastatic spread rather than from primary tumor burden. The goal of the study was to establish and apply rat MAT-Lu prostate cancer tumor models for improved non-invasive live follow up of tumor growth and metastasis by in vivo bioluminescence. We established luciferase transduced MAT-Lu rat PCa cells and studied tumor growth and metastatic processes in an ectopic as well as orthotopic setting. An intravenous bolus treatment with doxorubicin was used to demonstrate the basic applicability of in vivo imaging to follow up therapeutic intervention in these models. In vitro analysis of tissue homogenates confirmed major metastatic spread of subcutaneous tumors into the lung. Our sensitive method, however, for the first time detects metastasis also in lymph node (11/24), spleen (3/24), kidney (4/24), liver (5/24), and bone tissue (femur or spinal cord - 5/20 and 12/20, respectively). Preliminary data of orthotopic implantation (three animals) showed metastatic invasion to investigated organs in all animals but with varying preference (e.g., to lymph nodes). Intravenous bolus treatment of MAT-Lu PCa with doxorubicin reduced subcutaneous tumor growth by about 50% and the number of animals affected by metastatic lesions in lymph nodes (0/4), lung (3/6) or lumbar spine (0/2), as determined by in vivo imaging and in vitro analysis. Additionally, the possible applicability of the luciferase transduced MAT-Lu model(s) to study basic principles of metronomic therapies via jugular vein catheter, using newly established active microport pumping systems, is presented.