Tumor-targeting nanocomplex delivery of novel tumor suppressor RB94 chemosensitizes bladder carcinoma cells in vitro and in vivo

Nanomedicine in cancer therapy

Cancer remains a highly lethal disease in the world. Currently, either conventional cancer therapies or modern immunotherapies are non-tumor-targeted therapeutic approaches that cannot accurately distinguish malignant cells from healthy ones, giving rise to multiple undesired side effects. Recent advances in nanotechnology, accompanied by our growing understanding of cancer biology and nano-bio interactions, have led to the development of a series of nanocarriers, which aim to improve the therapeutic efficacy while reducing off-target toxicity of the encapsulated anticancer agents through tumor tissue-, cell-, or organelle-specific targeting. However, the vast majority of nanocarriers do not possess hierarchical targeting capability, and their therapeutic indices are often compromised by either poor tumor accumulation, inefficient cellular internalization, or inaccurate subcellular localization. This Review outlines current and prospective strategies in the design of tumor tissue-, cell-, and organelle-targeted cancer nanomedicines, and highlights the latest progress in hierarchical targeting technologies that can dynamically integrate these three different stages of static tumor targeting to maximize therapeutic outcomes. Finally, we briefly discuss the current challenges and future opportunities for the clinical translation of cancer nanomedicines.

MiR-126-Loaded Immunoliposomes against Vascular Endothelial Inflammation In Vitro and Vivo Evaluation

Due to the accompaniment of vascular endothelial inflammation during the occurrence and development of cardiovascular diseases (CVD), treatment modalities against vascular endothelial inflammation have been intensively investigated for CVD prevention and/or treatment. Vascular cell adhesion molecule-1 (VCAM-1) is a typical transmembrane inflammatory protein specifically expressed by inflammatory vascular endothelial. By inhibiting VCAM-1 expression through the miR-126 mediated pathway, vascular endothelial inflammation can be efficiently relieved. Inspired by this, we developed a miR-126-loaded immunoliposome with VCAM-1 monoclonal antibody (VCAM_ab) decorated at its surface. This immunoliposome can be directly targeted to VCAM-1 at the inflammatory vascular endothelial membrane surface and achieve highly efficient treatment against inflammation response. The cellular experiment results showed the immunoliposome had a higher uptake rate towards inflammatory human vein endothelial cells (HUVECs) and can significantly downregulate the VCAM-1 expression level of inflammatory HUVECs. In vivo investigation further demonstrated that this immunoliposome displayed a higher accumulation rate at vascular inflammatory dysfunction sites than its non-VCAM_ab-modified counterpart. These results suggest that this novel nanoplatform can effectively deliver miR-126 to vascular inflammatory endothelium, opening a new avenue for the safe and effective delivery of miRNA for potential clinical application.

Lipid-based nucleic acid therapeutics with in vivo efficacy

Synthetic vectors for therapeutic nucleic acid delivery are currently competing significantly with their viral counter parts due to their reduced immunogenicity, large payload capacity, and ease of manufacture under GMP-compliant norms. The approval of Onpattro, a lipid-based siRNA therapeutic, and the proven clinical success of two lipid-based COVID-19 vaccines from Pfizer-BioNTech, and Moderna heralded the specific advantages of lipid-based systems among all other synthetic nucleic acid carriers. Lipid-based systems with diverse payloads-plasmid DNA (pDNA), antisense oligonucleotide (ASO), small interfering RNA (siRNA), microRNA (miRNA), small activating RNA (saRNA), and messenger RNA (mRNA)-are now becoming a mature technology, with growing impact in the clinic. Research over four decades identified the key factors determining the therapeutic success of these multi-component systems. Here, we discuss the main nucleic acid-based technologies, presenting their mechanism of action, delivery barriers facing them, the structural properties of the payload as well as the component lipids that regulate physicochemical properties, pharmacokinetics and biodistribution, efficacy, and toxicity of the resultant nanoparticles. We further detail on the formulation parameters, evolution of the manufacturing techniques that generate reproducible and scalable outputs, and key manufacturing aspects that enable control over physicochemical properties of the resultant particles. Preclinical applications of some of these formulations that were successfully translated from in vitro studies to animal models are subsequently discussed. Finally, clinical success and failure of these systems starting from 1993 to present are highlighted, in a holistic literature review focused on lipid-based nucleic acid delivery systems. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials.

Nanomedicine-Based Gene Delivery for a Truncated Tumor Suppressor RB94 Promotes Lung Cancer Immunity

Because lung cancer remains the most common and lethal of cancers, novel therapeutic approaches are urgently needed. RB94 is a truncated form of retinoblastoma tumor suppressor protein with elevated anti-tumor efficacy. Our investigational nanomedicine (termed scL-RB94) is a tumor-targeted liposomal formulation of a plasmid containing the gene encoding RB94. In this research, we studied anti-tumor and immune modulation activities of scL-RB94 nanocomplex in preclinical models of human non-small cell lung cancer (NSCLC). Systemic treatment with scL-RB94 of mice bearing human NSCLC tumors significantly inhibited tumor growth by lowering proliferation and increasing apoptosis of tumor cells in vivo. scL-RB94 treatment also boosted anti-tumor immune responses by upregulating immune recognition molecules and recruiting innate immune cells such as natural killer (NK) cells. Antibody-mediated depletion of NK cells blunted the anti-tumor activity of scL-RB94, suggesting that NK cells were crucial for the observed anti-tumor activity in these xenograft models. Treatment with scL-RB94 also altered the polarization of tumor-associated macrophages by reducing immune-suppressive M2 macrophages to lower immune suppression in the tumor microenvironment. Collectively, our data suggest that the efficacy of scL-RB94 against NSCLC is due to an induction of tumor cell death as well as enhancement of innate anti-tumor immunity.

Nanocarriers: A Reliable Tool for the Delivery of Anticancer Drugs

Nanomedicines have gained popularity due to their potential therapeutic applications, especially cancer treatment. Targeted nanoparticles can deliver drugs directly to cancer cells and enable prolonged drug release, reducing off-target toxicity and increasing therapeutic efficacy. However, translating nanomedicines from preclinical to clinical settings has been difficult. Rapid advancements in nanotechnology promise to enhance cancer therapies. Nanomedicine offers advanced targeting and multifunctionality. Nanoparticles (NPs) have several uses nowadays. They have been studied as drug transporters, tumor gene delivery agents, and imaging contrast agents. Nanomaterials based on organic, inorganic, lipid, or glycan substances and synthetic polymers have been used to enhance cancer therapies. This review focuses on polymeric nanoparticle delivery strategies for anticancer nanomedicines.

Nanoparticles for vaccine and gene therapy: Overcoming the barriers to nucleic acid delivery

Nucleic acid therapeutics can be used to control virtually every aspect of cell behavior and therefore have significant potential to treat genetic disorders, infectious diseases, and cancer. However, while clinically approved to treat a small number of diseases, the full potential of nucleic acid therapeutics is hampered by inefficient delivery. Nucleic acids are large, highly charged biomolecules that are sensitive to degradation and so the approaches to deliver these molecules differ significantly from traditional small molecule drugs. Current studies suggest less than 1% of the injected nucleic acid dose is delivered to the target cell in an active form. This inefficient delivery increases costs and limits their use to applications where a small amount of nucleic acid is sufficient. In this review, we focus on two of the major barriers to efficient nucleic acid delivery: (1) delivery to the target cell and (2) transport to the subcellular compartment where the nucleic acids are therapeutically active. We explore how nanoparticles can be modified with targeting ligands to increase accumulation in specific cells, and how the composition of the nanoparticle can be engineered to manipulate or disrupt cellular membranes and facilitate delivery to the optimal subcellular compartments. Finally, we highlight how with intelligent material design, nanoparticle delivery systems have been developed to deliver nucleic acids that silence aberrant genes, correct genetic mutations, and act as both therapeutic and prophylactic vaccines. This article is categorized under: Nanotechnology Approaches to Biology > Cells at the Nanoscale Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Biology-Inspired Nanomaterials > Lipid-Based Structures.

Application of nanotechnology in the diagnosis and treatment of bladder cancer

Bladder cancer (BC) is a common malignancy in the genitourinary system and the current theranostic approaches are unsatisfactory. Sensitivity and specificity of current diagnosis methods are not ideal and high recurrence and progression rates after initial treatment indicate the urgent need for management improvements in clinic. Nanotechnology has been proposed as an effective method to improve theranosis efficiency for both non-muscle invasive bladder cancer (NMIBC) and muscle invasive bladder cancer (MIBC). For example, gold nanoparticles (AuNPs) have been developed for simple, fast and sensitive urinary sample test for bladder cancer diagnosis. Nanoparticles targeting bladder cancers can facilitate to distinguish the normal and abnormal bladder tissues during cystoscopy and thus help with the complete removal of malignant lesions. Both intravenous and intravesical agents can be modified by nanotechnology for targeted delivery, high anti-tumor efficiency and excellent tolerability, exhibiting encouraging potential in bladder cancer treatment. Photosensitizers and biological agents can also be delivered by nanotechnology, intermediating phototherapy and targeted therapy. The management of bladder cancer remained almost unchanged for decades with unsatisfactory effect. However, it is likely to change with the fast-developed nanotechnology. Herein we summarized the current utility of nanotechnology in bladder cancer diagnosis and treatment, providing insights for the future designing and discovering novel nanoparticles for bladder cancer management.

A selective drug delivery system based on phospholipid-type nanobubbles for lung cancer therapy

Aim: To develop a micelle-type nanobubble decorated with fluorescein-5-isothiocyanate-conjugated transferrin, with encapsulation of paclitaxel (PTX@FT-NB) for lung cancer treatment. Materials & methods: PTX@FT-NBs were characterized to determine their physicochemical properties, structural stability and cytotoxicity. Lung cancer cell and mouse xenograft tumor models were used to evaluate the therapeutic effectiveness of PTX@FT-NB. Results: The PTX@FT-NBs not only showed selective targeting to lung cancer cells but also inhibited tumor growth significantly via paclitaxel release. Furthermore, paclitaxel-induced microtubule stabilization demonstrated the release of the drug from PTX@FT-NB in the targeted tumor cell both in vitro and in vivo. Conclusion: PTX@FT-NB has the potential as an anticancer nanocarrier against lung cancer cells because of its specific targeting and better drug delivery capacity.

Improving the therapeutic efficiency of noncoding RNAs in cancers using targeted drug delivery systems

The delivery of noncoding (nc)RNA to target cancer stem cells and metastatic tumors has shown many positive outcomes, resulting in improved and more efficient treatment strategies. The success of therapeutic RNA depends solely on passing cellular barriers to reach the target site, where it binds to the mRNA of the interest. By 2018, 20 clinical trials had been initiated, most focusing on cancer and diabetes, with some progressing to Phase II clinical trials testing the safety and efficacy of small interfering (si)RNA. Many challenges limit RNA interference (RNAi) and miRNA usage in vivo; therefore, various approaches have been developed to promote ncRNA efficiency and stability. In this review, we focus on targeting the tumor microenvironment (TME) via the modification of delivery systems utilizing nanotechnology-based delivery approaches.

Laminin-derived peptides: Applications in drug delivery systems for targeting

Recently, the development of drug delivery systems (DDSs) for clinical application of anticancer drugs and gene therapy has rapidly progressed. In particular, DDS carriers used for chemotherapy and gene therapy are required to selectively deliver drugs and genes to cancer cells. Both the carrier and the molecule must in combination be highly selective in most cases. Possible candidate targeting molecules are the laminins, major basement membrane proteins that interact with various cells through their multiple constituent active peptide sequences. Laminin-derived peptides bind to various cellular receptors and have been used for DDSs as a targeting moiety. Here, we review the progress in laminin-derived peptide-conjugated DDSs. Drug and gene carriers as well as ultrasound diagnostic contrast agents utilizing laminin-derived peptides for selective targeting are useful components of DDSs and play important roles in cancer and in the neovasculature.

Lipid-Based DNA Therapeutics: Hallmarks of Non-Viral Gene Delivery

Gene therapy is a promising strategy for the treatment of monogenic disorders. Non-viral gene delivery systems including lipid-based DNA therapeutics offer the opportunity to deliver an encoding gene sequence specifically to the target tissue and thus enable the expression of therapeutic proteins in diseased cells. Currently, available gene delivery approaches based on DNA are inefficient and require improvements to achieve clinical utility. In this Review, we discuss state-of-the-art lipid-based DNA delivery systems that have been investigated in a preclinical setting. We emphasize factors influencing the delivery and subsequent gene expression in vitro, ex vivo, and in vivo. In addition, we cover aspects of nanoparticle engineering and optimization for DNA therapeutics. Finally, we highlight achievements of lipid-based DNA therapies in clinical trials.

Targeting Non-coding RNA in Vascular Biology and Disease

Only recently have we begun to appreciate the importance and complexity of the non-coding genome, owing in some part to truly significant advances in genomic technology such as RNA sequencing and genome-wide profiling studies. Previously thought to be non-functional transcriptional “noise,” non-coding RNAs (ncRNAs) are now known to play important roles in many diverse biological pathways, not least in vascular disease. While microRNAs (miRNA) are known to regulate protein-coding gene expression principally through mRNA degradation, long non-coding RNAs (lncRNAs) can activate and repress genes by a variety of mechanisms at both transcriptional and translational levels. These versatile molecules, with complex secondary structures, may interact with chromatin, proteins, and other RNA to form complexes with an array of functional consequences. A body of emerging evidence indicates that both classes of ncRNAs regulate multiple physiological and pathological processes in vascular physiology and disease. While dozens of miRNAs are now implicated and described in relative mechanistic depth, relatively fewer lncRNAs are well described. However, notable examples include ANRIL, SMILR, and SENCR in vascular smooth muscle cells; MALAT1 and GATA-6S in endothelial cells; and mitochondrial lncRNA LIPCAR as a powerful biomarker. Due to such ubiquitous involvement in pathology and well-known biogenesis and functional genetics, novel miRNA-based therapies and delivery methods are now in development, including some early stage clinical trials. Although lncRNAs may hold similar potential, much more needs to be understood about their relatively complex molecular behaviours before realistic translation into novel therapies. Here, we review the current understanding of the mechanism and function of ncRNA, focusing on miRNAs and lncRNAs in vascular disease and atherosclerosis. We discuss existing therapies and current delivery methods, emphasising the importance of miRNAs and lncRNAs as effectors and biomarkers in vascular pathology.

Small cell carcinoma of the urinary bladder: a clinicopathological and immunohistochemical analysis of 81 cases

Small cell carcinoma (SmCC) of the bladder is a rare disease. We retrospectively studied a large series of bladder SmCC from a single institution. The patients included 69 men and 12 women with a mean age of 68 years. Most bladder SmCCs were presented at advanced stage, with tumors invading the muscularis propria and beyond (n = 77). SmCC was pure in 27 cases and mixed with other histologic types in 54 cases, including urothelial carcinoma (UC) (n = 32), UC in situ (n = 26), glandular (n = 14), micropapillary (n = 4), sarcomatoid (n = 4), squamous (n = 3), and plasmacytoid (n = 1) features. Most SmCCs expressed neuroendocrine markers synaptophysin (41/56), chromogranin (26/55), and CD56 (39/41); however, they did not express UC luminal markers CK20 (0/17), GATA3 (1/30), and uroplakin II (1/22). Some SmCCs showed focal expression of CK5/6 (9/25), a marker for the basal molecular subtype. Furthermore, expression of the retinoblastoma 1 (RB1) gene protein was lost in most of the bladder SmCCs (2/23). The patients' survival was significantly associated with cancer stage but did not show a significant difference between mixed and pure SmCCs. Compared with conventional UC at similar stages, SmCC had a worse prognosis only when patients developed metastatic diseases. In conclusion, bladder SmCC is an aggressive disease that is frequently present at an advanced stage. A fraction of SmCCs show a basal molecular subtype, which may underlie its good response to chemotherapy. Inactivation of the RB1 gene may be implicated in the oncogenesis of bladder SmCC.

Plasmacytoid Urothelial Carcinoma of the Urinary Bladder: A Clinicopathologic and Immunohistochemical Analysis of 49 Cases

OBJECTIVES

Plasmacytoid urothelial carcinoma (PUC) of the bladder is a rare histologic variant. We retrospectively analyzed a large series of bladder PUC from a single institution.

METHODS

The patients consisted of 44 men and five women with a mean age of 62 years (range, 45-86 years).

RESULTS

PUC was pure in 23 cases and mixed with other histologic types in 26 cases. All PUCs diffusely invaded the bladder wall. Most PUCs lacked immunoreactivity for the retinoblastoma (RB) gene protein (12/32) and E-cadherin (8/30). Of the 44 patients with follow-up information, 25 died of PUC at a mean of 23 months, whereas 19 patients were alive at a mean of 22 months.

CONCLUSIONS

Our findings support that bladder PUC is a highly aggressive disease. The lack of E-cadherin expression in PUCs may underlie the distinct discohesive histologic appearance, and abnormal function of the RB gene may be implicated in the development of PUC.

Targeting noncoding RNAs in disease

Many RNA species have been identified as important players in the development of chronic diseases, including cancer. Over the past decade, numerous studies have highlighted how regulatory RNAs such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) play crucial roles in the development of a disease state. It is clear that the aberrant expression of miRNAs promotes tumor initiation and progression, is linked with cardiac dysfunction, allows for the improper physiological response in maintaining glucose and insulin levels, and can prevent the appropriate integration of neuronal networks, resulting in neurodegenerative disorders. Because of this, there has been a major effort to therapeutically target these noncoding RNAs. In just the past 5 years, over 100 antisense oligonucleotide-based therapies have been tested in phase I clinical trials, a quarter of which have reached phase II/III. Most notable are fomivirsen and mipomersen, which have received FDA approval to treat cytomegalovirus retinitis and high blood cholesterol, respectively. The continued improvement of innovative RNA modifications and delivery entities, such as nanoparticles, will aid in the development of future RNA-based therapeutics for a broader range of chronic diseases. Here we summarize the latest promises and challenges of targeting noncoding RNAs in disease.

Improved Targeting of Cancers with Nanotherapeutics

Targeted cancer nanotherapeutics offers numerous opportunities for the selective uptake of toxic chemotherapies within tumors and cancer cells. The unique properties of nanoparticles, such as their small size, large surface-to-volume ratios, and the ability to achieve multivalency of targeting ligands on their surface, provide superior advantages for nanoparticle-based drug delivery to a variety of cancers. This review highlights various key concepts in the design of targeted nanotherapeutics for cancer therapy, and discusses physicochemical parameters affecting nanoparticle targeting, along with recent developments for cancer-targeted nanomedicines.

Tumor-targeted nanomedicines for cancer theranostics

Chemotherapeutic drugs have multiple drawbacks, including severe side effects and suboptimal therapeutic efficacy. Nanomedicines assist in improving the biodistribution and target accumulation of chemotherapeutic drugs, and are therefore able to enhance the balance between efficacy and toxicity. Multiple types of nanomedicines have been evaluated over the years, including liposomes, polymer-drug conjugates and polymeric micelles, which rely on strategies such as passive targeting, active targeting and triggered release for improved tumor-directed drug delivery. Based on the notion that tumors and metastases are highly heterogeneous, it is important to integrate imaging properties in nanomedicine formulations in order to enable non-invasive and quantitative assessment of targeting efficiency. By allowing for patient pre-selection, such next generation nanotheranostics are useful for facilitating clinical translation and personalizing nanomedicine treatments.

A Phase l Study of a Tumor-targeted Systemic Nanodelivery System, SGT-94, in Genitourinary Cancers

Gene therapy development has been limited by our inability to target multifocal cancer with systemic delivery. We developed a systemically administered, tumor-targeted liposomal nanodelivery complex (SGT-94) carrying a plasmid encoding RB94, a truncated form of the RB gene. In preclinical studies, RB94 showed marked cytotoxicity against tumor but not normal cells. SGT-94 was administered intravenously in a first-in-man study in metastatic genitourinary cancer. Minimal side effects were observed; dose-limiting toxicity (DLT) has not been reached in 11 evaluable patients. There was evidence of clinical activity at the 2.4 mg dose with one complete remission (CR) and one partial remission (PR). The patient in CR was retreated upon progression and had a second PR. Furthermore, there was tumor-specific targeting of the SGT-94 complex. One patient had wedge resections of two lung metastases which demonstrated RB94 expression at the DNA level by polymerase chain reaction (PCR) and at the protein level by Western blotting, with no RB94 present in normal contiguous lung. In conclusion, systemically delivered SGT-94 showed evidence of selective tumor targeting and was well tolerated with evidence of clinical activity. Additional studies are warranted to explore the activity of this drug as a single agent and in combination therapy.

Bladder tumor-targeted delivery of pro-apoptotic peptide for cancer therapy

The overall prognosis of conventional chemotherapy for the treatment of bladder cancer is poor and reduction of its systemic side effects remains an unsolved issue. Targeted therapy for bladder cancer could improve therapeutic efficacy and reduce side effects. This study investigated a hybrid peptide (named Bld-1-KLA) composed of the CSNRDARRC peptide (Bld-1), which binds to bladder tumor cells, and the d-KLAKLAKKLAKLAK (KLA) peptide, which disrupts mitochondrial membrane and induces apoptotic cell death, as a bladder cancer-targeted therapeutic agent. Bld-1-KLA selectively bound to HT1376 bladder tumor cells and efficiently internalized into the cells but not to other types of tumor and normal cell lines. Bld-1-KLA exerted cytotoxic effects selectively to HT1376 cells (LC50=41.5μM), but not to other types of cells. Pretreatment of cells with Bld-1 inhibited the binding and cytotoxicity by Bld-1-KLA in HT1376 cells. It induced apoptosis of bladder tumor cells, while Bld-1 or KLA alone showed much lesser effect on apoptosis, and was co-localized in mitochondria. Bld-1-KLA was stable up to 24h in serum. In vivo fluorescence imaging showed that homing of Bld-1-KLA in the tumor in HT1376 tumor-bearing nude mice was greater than that of the control peptide-KLA after intravenous injection. Treatment of tumor-bearing mice with Bld-1-KLA, compared to the control peptide-KLA, induced apoptosis of tumor cells and inhibited tumor growth more efficiently. No significant side effects on body weight and the liver and myeloid function were observed in mice treated with Bld-1-KLA. These results suggest that Bld-1-KLA is a promising therapeutic agent for targeted therapy of bladder cancer.

Glycoengineered mesenchymal stem cells as an enabling platform for two-step targeting of solid tumors

Current tumor targeted drug and diagnostic delivery systems suffer from a lack of selectivity for tumor cells. Here, we propose a two-step tumor targeting strategy based on mesenchymal stem cells (MSCs), which actively traffic to tumors. We developed glycoengineering protocols to induce expression of non-natural azide groups on the surface of MSCs without affecting their viability or tumor homing properties. Glycoengineered MSCs demonstrated active tumor homing in subcutaneous and orthotopic lung and ovarian tumor models. Subsequent systemic administration of dibenzyl cyclooctyne (DBCO)-labeled fluorophores or nanoparticles to MSC pretreated mice resulted in enhanced tumor accumulation of these agents through bio-orthogonal copper-free click chemistry. Further, administration of glycoengineered MSCs along with paclitaxel-loaded DBCO-functionalized nanoparticles resulted in significant (p < 0.05) inhibition of tumor growth and improved survival (p < 0.0001) in an orthotopic metastatic ovarian tumor model. These results provide evidence for the potential of MSC-based two-step targeting strategy to improve the tumor specificity of diagnostic agents and drugs, and thus potentially improve the treatment outcomes for patients diagnosed with cancer.

Encapsulation of temozolomide in a tumor-targeting nanocomplex enhances anti-cancer efficacy and reduces toxicity in a mouse model of glioblastoma

Although temozolomide (TMZ) is the current first-line chemotherapy for glioblastoma multiforme (GBM), most patients either do not respond or ultimately fail TMZ treatment. Both intrinsic tumor resistance and limited access of TMZ to brain tumors as a result of the blood-brain barrier (BBB) contribute to poor response and ultimately to poor prognosis for GBM patients. We have developed a "dual-targeting" nanomedicine that both actively crosses the BBB and actively targets cancer cells once in the brain parenchyma. This nanomedicine (termed scL-TMZ) is sized ~40 nm and comprised of a cationic liposome (DOTAP:DOPE) encapsulating TMZ. The surface of liposome is decorated with anti-transferrin receptor single-chain antibody fragments to facilitate the crossing of the BBB by the scL-TMZ in addition to targeting GBM in the brain. This novel formulation was found to be markedly more effective than standard TMZ in both TMZ-resistant and TMZ-sensitive GBM. Encapsulation of TMZ also markedly enhanced its efficacy in killing a variety of non-GBM tumor cells. The scL-TMZ nanocomplex was shown to target cancer stem cells, which have been linked to both drug resistance and recurrence in GBM. Most significantly, systemically administered scL-TMZ significantly prolonged survival in mice bearing intracranial GBM tumors. The improved efficacy of scL-TMZ compared to standard TMZ was accompanied by reduced toxicity, so we conclude that the scL-TMZ nanomedicine holds great promise as a more effective therapy for GBM and other tumor types.

Nanotechnology in bladder cancer: current state of development and clinical practice

Nanotechnology is being developed for the diagnosis and treatment of both nonmyoinvasive bladder cancer (NMIBC) and invasive bladder cancer. The diagnostic applications of nanotechnology in NMIBC mainly focus on tumor identification during endoscopy to increase complete resection of bladder cancer while nanotechnology to capture malignant cells or their components continues to be developed. The therapeutic applications of nanotechnology in NMIBC are to reformulate biological and cytotoxic agents for intravesical instillation, combine both diagnostic and therapeutic application in one nanoformulation. In invasive and advanced bladder cancer, magnetic resonance imaging with supraparamagnetic iron oxide nanoparticles can improve the sensitivity and specificity in detecting small metastasis to lymph nodes. Nanoformulation of cytotoxic agents can potentially decrease the toxicity while increasing efficacy.

Nanomedicine in cancer therapy: challenges, opportunities, and clinical applications

Cancer is a leading cause of death worldwide. Currently available therapies are inadequate and spur demand for improved technologies. Rapid growth in nanotechnology towards the development of nanomedicine products holds great promise to improve therapeutic strategies against cancer. Nanomedicine products represent an opportunity to achieve sophisticated targeting strategies and multi-functionality. They can improve the pharmacokinetic and pharmacodynamic profiles of conventional therapeutics and may thus optimize the efficacy of existing anti-cancer compounds. In this review, we discuss state-of-the-art nanoparticles and targeted systems that have been investigated in clinical studies. We emphasize the challenges faced in using nanomedicine products and translating them from a preclinical level to the clinical setting. Additionally, we cover aspects of nanocarrier engineering that may open up new opportunities for nanomedicine products in the clinic.

A tumor-targeting p53 nanodelivery system limits chemoresistance to temozolomide prolonging survival in a mouse model of glioblastoma multiforme

Development of temozolomide (TMZ) resistance contributes to the poor prognosis for glioblastoma multiforme (GBM) patients. It was previously demonstrated that delivery of exogenous wild-type tumor suppressor gene p53 via a tumor-targeted nanocomplex (SGT-53) which crosses the blood-brain barrier could sensitize highly TMZ-resistant GBM tumors to TMZ. Here we assessed whether SGT-53 could inhibit development of TMZ resistance. SGT-53 significantly chemosensitized TMZ-sensitive human GBM cell lines (U87 and U251), in vitro and in vivo. Furthermore, in an intracranial GBM tumor model, two cycles of concurrent treatment with systemically administered SGT-53 and TMZ inhibited tumor growth, increased apoptosis and most importantly, significantly prolonged median survival. In contrast TMZ alone had no significant effect on median survival compared to a single cycle of TMZ. These results suggest that combining SGT-53 with TMZ appears to limit development of TMZ resistance, prolonging its anti-tumor effect and could be a more effective therapy for GBM.

FROM THE CLINICAL EDITOR

Using human glioblastoma multiforma cell lines, this research team demonstrated that the delivery of exogenous wild-type tumor suppressor gene p53 via a tumor-targeted nanocomplex limited the development of temozolomide resistance and prolonged its anti-tumor effect, which may enable future human application of this or similar techniques.

A nanoparticle carrying the p53 gene targets tumors including cancer stem cells, sensitizes glioblastoma to chemotherapy and improves survival

Temozolomide (TMZ)-resistance in glioblastoma multiforme (GBM) has been linked to upregulation of O(6)-methylguanine-DNA methyltransferase (MGMT). Wild-type (wt) p53 was previously shown to down-modulate MGMT. However, p53 therapy for GBM is limited by lack of efficient delivery across the blood brain barrier (BBB). We have developed a systemic nanodelivery platform (scL) for tumor-specific targeting (primary and metastatic), which is currently in multiple clinical trials. This self-assembling nanocomplex is formed by simple mixing of the components in a defined order and a specific ratio. Here, we demonstrate that scL crosses the BBB and efficiently targets GBM, as well as cancer stem cells (CSCs), which have been implicated in recurrence and treatment resistance in many human cancers. Moreover, systemic delivery of scL-p53 down-modulates MGMT and induces apoptosis in intracranial GBM xenografts. The combination of scL-p53 and TMZ increased the antitumor efficacy of TMZ with enhanced survival benefit in a mouse model of highly TMZ-resistant GBM. scL-p53 also sensitized both CSCs and bulk tumor cells to TMZ, increasing apoptosis. These results suggest that combining scL-p53 with standard TMZ treatment could be a more effective therapy for GBM.

Targeted delivery system of nanobiomaterials in anticancer therapy: from cells to clinics

Targeted delivery systems of nanobiomaterials are necessary to be developed for the diagnosis and treatment of cancer. Nanobiomaterials can be engineered to recognize cancer-specific receptors at the cellular levels and to deliver anticancer drugs into the diseased sites. In particular, nanobiomaterial-based nanocarriers, so-called nanoplatforms, are the design of the targeted delivery systems such as liposomes, polymeric nanoparticles/micelles, nanoconjugates, norganic materials, carbon-based nanobiomaterials, and bioinspired phage system, which are based on the nanosize of 1-100 nm in diameter. In this review, the design and the application of these nanoplatforms are discussed at the cellular levels as well as in the clinics. We believe that this review can offer recent advances in the targeted delivery systems of nanobiomaterials regarding in vitro and in vivo applications and the translation of nanobiomaterials to nanomedicine in anticancer therapy.

The clinical potential of targeted nanomedicine: delivering to cancer stem-like cells

Cancer stem-like cells (CSCs) have been implicated in recurrence and treatment resistance in many human cancers. Thus, a CSC-targeted drug delivery strategy to eliminate CSCs is a desirable approach for developing a more effective anticancer therapy. We have developed a tumor-targeting nanodelivery platform (scL) for systemic administration of molecular medicines. Following treatment with the scL nanocomplex carrying various payloads, we have observed exquisite tumor-targeting specificity and significant antitumor response with long-term survival benefit in numerous animal models. We hypothesized that this observed efficacy might be attributed, at least in part, to elimination of CSCs. Here, we demonstrate the ability of scL to target both CSCs and differentiated nonstem cancer cells (non-CSCs) in various mouse models including subcutaneous and intracranial xenografts, syngeneic, and chemically induced tumors. We also show that systemic administration of scL carrying the wtp53 gene was able to induce tumor growth inhibition and the death of both CSCs and non-CSCs in subcutaneous colorectal cancer xenografts suggesting that this could be an effective method to reduce cancer recurrence and treatment resistance. This scL nanocomplex is being evaluated in a number of clinical trials where it has been shown to be well tolerated with indications of anticancer activity.

Ligand-targeted particulate nanomedicines undergoing clinical evaluation: current status

Since the introduction of Doxil® on the market nearly 20years ago, a number of nanomedicines have become part of treatment regimens in the clinic. With the exception of antibody-drug conjugates, these nanomedicines are all devoid of targeting ligands and rely solely on their physicochemical properties and the (patho)physiological processes in the body for their biodistribution and targeting capability. At the same time, many preclinical studies have reported on nanomedicines exposing targeting ligands, or ligand-targeted nanomedicines, yet none of these have been approved at this moment. In the present review, we provide a concise overview of 13 ligand-targeted particulate nanomedicines (ligand-targeted PNMs) that have progressed into clinical trials. The progress of each ligand-targeted PNM is discussed based on available (pre)clinical data. Main conclusions of these analyses are that (a) ligand-targeted PNMs have proven to be safe and efficacious in preclinical models; (b) the vast majority of ligand-targeted PNMs is generated for the treatment of cancer; (c) contribution of targeting ligands to the PNM efficacy is not unambiguously proven; and (d) targeting ligands do not cause localization of the PNM within the target tissue, but rather provide benefits in terms of target cell internalization and target tissue retention once the PNM has arrived at the target site. Increased understanding of the in vivo fate and interactions of the ligand-targeted PNMs with proteins and cells in the human body is mandatory to rationally advance the clinical translation of ligand-targeted PNMs. Future perspectives for ligand-targeted PNM approaches include the delivery of drugs that are unable or inefficient in passing cellular membranes, treatment of drug resistant tumors, targeting of the tumor blood supply, the generation of targeted vaccines and nanomedicines that are able to cross the blood-brain barrier.

Transferrin receptor targeting nanomedicine delivering wild-type p53 gene sensitizes pancreatic cancer to gemcitabine therapy

To overcome gene therapy barriers such as low transfection efficiency and nonspecific delivery, liposomal nanoparticles targeted by a single-chain antibody fragment to the transferrin receptor (TfRscFv) delivering wild-type (wt) human p53 (SGT-53) were developed for tumor-specific targeting. We hypothesize that SGT-53 in combination with gemcitabine will demonstrate enhanced therapeutic benefit in an in vivo metastatic pancreatic cancer model. Intrasplenic injection of 1 × 10(6) Panc02 murine pancreatic cancer cells was used to generate in vivo hepatic metastatic tumors. Nanoparticle localization was assessed by tail vein injection of TfRscFv with fluorescently labeled oligonucleotides (6-carboxyfluorescein phosphoramidite (6FAM) ODN) imaged by Xenogen IVIS 200 scan. SGT-53 (equivalent to 30 μg of p53 intravenously) and gemcitabine (20 mg/kg intraperitoneally) alone and in combination were administered biweekly and compared with untreated mice. Survival was determined by blinded daily assessment of morbidity. Human wtp53 expression and transferrin levels in the tumors were assessed by western blot analysis. Tumor burden was quantified by liver weight. Xenogen imaging demonstrated tumor-specific uptake of TfRscFv-6FAM ODN. Exogenous human wtp53 protein was detected in the SGT-53-treated tumors compared with control. Compared with untreated mice with metastatic tumors demonstrating median survival of 20 days, SGT-53, gemcitabine and the combination demonstrated improved median survival of 29, 30 and 37 days, respectively. The combination treatment prolonged median survival when compared with single drug treatment and decreased tumor burden. The tumor targeting liposomal-based SGT-53 nanoparticle is capable of sensitizing pancreatic cancer to conventional chemotherapy in pancreatic cancer models. This approach has the potential to be translated into a new, more effective therapy for pancreatic cancer. Further optimization is ongoing, moving towards a Phase 1B/2 clinical trial.

Experimental research of RB94 gene transfection into retinoblastoma cells using ultrasound-targeted microbubble destruction

The purpose of this study was to explore the transfection of the recombinant expression plasmid pEGFP-C1/RB94 into human retinoblastoma cells (HXO-Rb44) using ultrasound-targeted microbubble destruction (UTMD). pEGFP-C1/RB94 was transfected into HXO-Rb44 in vitro by UTMD, with liposome as the positive control. After 24 to 72 h, the expression of the reporter gene enhanced green fluorescent protein (EGFP) was observed using fluorescent microscopy and flow cytometry. The cell viability of HXO-Rb44 was measured by a MTT assay. The mRNA and proteins of RB94, caspase-3 and Bax were analyzed by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Moreover, the apoptosis rate and cell cycle progression of the cells were detected by flow cytometry. This study demonstrated that UTMD can enhance the transfection efficiency of RB94, which has an obvious impact on the inhibition of the growth process of retinoblastoma cells, suggesting that the combination of UTMD and RB94 compounds might be a useful tool for use in the gene therapy of retinoblastoma.

Time to stratify? The retinoblastoma protein in castrate-resistant prostate cancer

It is generally held that the retinoblastoma (RB) tumor suppressor functions in multiple tissues to protect against tumor development. However, preclinical studies and analysis of tumor samples of early disease did not support an important role of RB loss in the origin of prostate cancer. By contrast, recent observations in the clinical setting and subsequent modeling of RB function indicate that the tumor suppressor has specialized roles in controlling androgen receptor expression in prostate cancer, and primarily functions to prevent progression to the castration-resistant stage of disease. Furthermore, preclinical models have now shown that loss of RB expression or functional activity decreases the effectiveness of hormone therapy, yet seems to increase sensitivity to a subset of chemotherapeutic agents. Here, the current state of knowledge regarding the implications of RB loss for prostate cancer progression will be reviewed, and potential opportunities for developing RB as a metric to predict therapeutic response will be considered.

A novel cationic liposome formulation for efficient gene delivery via a pulmonary route

The clinical success of gene therapy for lung cancer is not only dependent on efficient gene carriers but also on a suitable delivery route. A pulmonary delivery route can directly deliver gene vectors to the lung which is more efficient than a systemic delivery route. For gene carriers, cationic liposomes have recently emerged as leading non-viral vectors in worldwide gene therapy clinical trials. However, cytotoxic effects or apoptosis are often observed which is mostly dependent on the cationic lipid used. Therefore, an efficient and safe cationic lipid, 6-lauroxyhexyl lysinate (LHLN), previously synthesized by our group was first used to prepare cationic liposomes. Physicochemical and biological properties of LHLN-liposomes were investigated. LHLN-liposome/DNA complexes showed positive surface charge, spherical morphology, a relatively narrow particle size distribution and strong DNA binding capability. Compared with Lipofectamine2000, the new cationic liposome formulation using LHLN exhibited not only lower cytotoxicity (P < 0.05) but also similar transfection efficiency in A549 and HepG2 lung cancer cells for in vitro tests. When administered by intratracheal instillation into rat lungs for in vivo evaluation, LHLN-liposome/DNA complexes exhibited higher pulmonary gene transfection efficiency than Lipofectamine2000/DNA complexes (P < 0.05). These results suggested that LHLN-liposomes may have great potential for efficient pulmonary gene delivery.

8p22 MTUS1 gene product ATIP3 is a novel anti-mitotic protein underexpressed in invasive breast carcinoma of poor prognosis

BACKGROUND

Breast cancer is a heterogeneous disease that is not totally eradicated by current therapies. The classification of breast tumors into distinct molecular subtypes by gene profiling and immunodetection of surrogate markers has proven useful for tumor prognosis and prediction of effective targeted treatments. The challenge now is to identify molecular biomarkers that may be of functional relevance for personalized therapy of breast tumors with poor outcome that do not respond to available treatments. The Mitochondrial Tumor Suppressor (MTUS1) gene is an interesting candidate whose expression is reduced in colon, pancreas, ovary and oral cancers. The present study investigates the expression and functional effects of MTUS1 gene products in breast cancer.

METHODS AND FINDINGS

By means of gene array analysis, real-time RT-PCR and immunohistochemistry, we show here that MTUS1/ATIP3 is significantly down-regulated in a series of 151 infiltrating breast cancer carcinomas as compared to normal breast tissue. Low levels of ATIP3 correlate with high grade of the tumor and the occurrence of distant metastasis. ATIP3 levels are also significantly reduced in triple negative (ER- PR- HER2-) breast carcinomas, a subgroup of highly proliferative tumors with poor outcome and no available targeted therapy. Functional studies indicate that silencing ATIP3 expression by siRNA increases breast cancer cell proliferation. Conversely, restoring endogenous levels of ATIP3 expression leads to reduced cancer cell proliferation, clonogenicity, anchorage-independent growth, and reduces the incidence and size of xenografts grown in vivo. We provide evidence that ATIP3 associates with the microtubule cytoskeleton and localizes at the centrosomes, mitotic spindle and intercellular bridge during cell division. Accordingly, live cell imaging indicates that ATIP3 expression alters the progression of cell division by promoting prolonged metaphase, thereby leading to a reduced number of cells ungergoing active mitosis.

CONCLUSIONS

Our results identify for the first time ATIP3 as a novel microtubule-associated protein whose expression is significantly reduced in highly proliferative breast carcinomas of poor clinical outcome. ATIP3 re-expression limits tumor cell proliferation in vitro and in vivo, suggesting that this protein may represent a novel useful biomarker and an interesting candidate for future targeted therapies of aggressive breast cancer.

Early RB94-produced cytotoxicity in cancer cells is independent of caspase activation or 50 kb DNA fragmentation

RB94, which lacks the N-terminal 112 amino-acid residues of the full-length retinoblastoma protein (RB110) is a more potent inhibitor of cancer cell growth than RB110, being cytotoxic to all cancer cell lines studied, independent of their genetic abnormalities. Although we initially thought RB94-induced cell death was caspase-dependent, such caspase activation now appears to be a late event. Cells that remained attached 48 h after transduction with Ad-RB94 showed, among other changes, nuclear enlargement, peripheral nuclear chromatin condensation and often micronucleation. In addition, the cells were TdT-mediated dUTP nick end labeling (TUNEL) positive but showed no cleavage of caspase 3 or 9. Only after the cells detached was cleavage of both caspase 3 and 9 observed. These TUNEL-positive cells showed neither cytochrome c mitochondrial translocation usually found in typical apoptotic cells nor DNA laddering indicative of oligonucleosomal DNA fragmentation. In addition, although 50 kb DNA fragmentation was produced in these TUNEL-positive cells, which was dependent on apoptosis-inducing factor (AIF), inhibiting this fragmentation by siAIF did not inhibit TUNEL formation or cytotoxicity. As RB94 will soon be used for gene therapy further understanding the molecular basis of these early changes in killing cancer cells is one of our particularly important present goals.