Immunotherapy of advanced malignancy by direct gene transfer of an interleukin-2 DNA/DMRIE/DOPE lipid complex: phase I/II experience

Revitalizing Cytokine-Based Cancer Immunotherapy through Advanced Delivery Systems

Cytokines can coordinate robust immune responses, holding great promise as therapeutics against infections, autoimmune diseases, and cancers. In cancer treatment, numerous pro-inflammatory cytokines have displayed promising efficacy in preclinical studies. However, their clinical application is hindered by poor pharmacokinetics, significant toxicity and unsatisfactory anticancer efficacy. Thus, while IFN-α and IL-2 are approved for specific cancer treatments, other cytokines still remain subject of intense investigation. To accelerate the application of cytokines as cancer immunotherapeutics, strategies need to be directed to improve their safety and anticancer performance. In this regard, delivery systems could be used to generate innovative therapies by targeting the cytokines or nucleic acids, such as DNA and mRNA, encoding the cytokines to tumor tissues. This review centers on these innovative delivery strategies for cytokines, summarizing key approaches, such as gene delivery and protein delivery, and critically examining their potential and challenges for clinical translation.

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.

Molecular Dynamics Simulation of Transport Mechanism of Graphene Quantum Dots Through Different Cell Membranes

Exploring the mechanisms underlying the permeation of graphene quantum dots (GQDs) through different cell membranes is key for the practical application of GQDs in medicine. Here, the permeation process of GQDs through different lipid membranes was evaluated using molecular dynamics (MD) simulations. Our results showed that GQDs can easily permeate into 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) lipid membranes with low phospholipid molecule densities but cannot permeate into 1-palmitoyl-2-oleoyl phosphatidylethanolamine (POPE) lipid membranes with high phospholipid densities. Free energy calculation showed that a high-energy barrier exists on the surface of the POPE lipid membrane, which prevents GQDs from entering the cell membrane interior. Further analysis of the POPE membrane structure showed that sparsely arranged phospholipid molecules of the low-density lipid membrane facilitated the entry of GQDs into the interior of the membrane, compared to compactly arranged molecules in the high-density lipid membrane. Our simulation study provides new insights into the transmembrane transport of GQDs.

Considering the potential for gene-based therapy in prostate cancer

Therapeutic gene manipulation has been at the forefront of popular scientific discussion and basic and clinical research for decades. Basic and clinical research applications of CRISPR-Cas9-based technologies and ongoing clinical trials in this area have demonstrated the potential of genome editing to cure human disease. Evaluation of research and clinical trials in gene therapy reveals a concentration of activity in prostate cancer research and practice. Multiple aspects of prostate cancer care - including anatomical considerations that enable direct tumour injections and sampling, the availability of preclinical immune-competent models and the delineation of tumour-related antigens that might provide targets for an induced immune system - make gene therapy an appealing treatment option for this common malignancy. Vaccine-based therapies that induce an immune response and new technologies exploiting CRISPR-Cas9-assisted approaches, including chimeric antigen receptor (CAR) T cell therapies, are very promising and are currently under investigation both in the laboratory and in the clinic. Although laboratory and preclinical advances have, thus far, not led to oncologically relevant outcomes in the clinic, future studies offer great promise for gene therapy to become established in prostate cancer care.

A drug delivery perspective on intratumoral-immunotherapy in renal cell carcinoma

In less than 5years immune checkpoint inhibitors (ICI) went from first FDA approval to become first-line options in advanced renal cell carcinoma. Despite that many patients have benefited from ICI, a significant fraction of individuals are refractory to these new immunological treatments. In this review, we discussed using intratumoral (i.t.) route of drug administration as an alternative to systemic therapy to increase the response rates and to circumvent potential drug-induced systemic adverse events. We provided a historic account of i.t. drug treatments in cancer and reviewed the contemporary experience in local drug delivery. We discussed the potential for enhancing the therapeutic impact of ICI by leveraging hydrogels as drug delivery vehicles and presented an outlook for implementing i.t. in renal cell carcinoma.

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.

Immunomodulation of the Tumor Microenvironment: Turn Foe Into Friend

Immunotherapy, where the patient's own immune system is exploited to eliminate tumor cells, has become one of the most prominent new cancer treatment options in the last decade. The main hurdle for classical cancer vaccines is the need to identify tumor- and patient specific antigens to include in the vaccine. Therefore, in situ vaccination represents an alternative and promising approach. This type of immunotherapy involves the direct intratumoral administration of different immunomodulatory agents and uses the tumor itself as the source of antigen. The ultimate aim is to convert an immunodormant tumor microenvironment into an immunostimulatory one, enabling the immune system to eradicate all tumor lesions in the body. In this review we will give an overview of different strategies, which can be exploited for the immunomodulation of the tumor microenvironment and their emerging role in the treatment of cancer patients.

Addressing the Adult Soft Tissue Sarcoma Microenvironment with Intratumoral Immunotherapy

Sarcoma is comprised of a heterogeneous group of tumors originating from the mesenchyme. Sarcoma is also the first tumor that responded to immunotherapeutic agents often termed as “Coley's toxins.” However, immunotherapy is yet to establish its presence in sarcomas. Complex interactions between tumor and immune cells in the tumor microenvironment play a crucial role in response to immunotherapy. There is a dynamic equilibrium created by the immune cells infiltrating the tumor, and this forms the basis of tumor evasion. Manipulating the intratumoral microenvironment will help overcome tumor evasion.

Challenges in CRISPR/CAS9 Delivery: Potential Roles of Nonviral Vectors

CRISPR/Cas9 genome editing platforms are widely applied as powerful tools in basic research and potential therapeutics for genome regulation. The appropriate alternative of delivery system is critical if genome editing systems are to be effectively performed in the targeted cells or organisms. To date, the in vivo delivery of the Cas9 system remains challenging. Both physical methods and viral vectors are adopted in the delivery of the Cas9-based gene editing platform. However, physical methods are more applicable for in vitro delivery, while viral vectors are generally concerned with safety issues, limited packing capacities, and so on. With the robust development of nonviral drug delivery systems, lipid- or polymer-based nanocarriers might be potent vectors for the delivery of CRISPR/Cas9 systems. In this review, we look back at the delivery approaches that have been used for the delivery of the Cas9 system and outline the recent development of nonviral vectors that might be potential carriers for the genome editing platform in the future. The efforts in optimizing cationic nanocarriers with structural modification are described and promising nonviral vectors under clinical investigations are highlighted.

In situ vaccination: Cancer immunotherapy both personalized and off-the-shelf

As cancer immunotherapy continues to benefit from novel approaches which cut immune 'brake pedals' (e.g. anti-PD1 and anti-CTLA4 antibodies) and push immune cell gas pedals (e.g. IL2, and IFNα) there will be increasing need to develop immune 'steering wheels' such as vaccines to guide the immune system specifically toward tumor associated antigens. Two primary hurdles in cancer vaccines have been: identification of universal antigens to be used in 'off-the-shelf' vaccines for common cancers, and 2) logistical hurdles of ex vivo production of individualized whole tumor cell vaccines. Here we summarize approaches using 'in situ vaccination' in which intratumoral administration of off-the-shelf immunomodulators have been developed to specifically induce (or amplify) T cell responses to each patient's individual tumor. Clinical studies have confirmed the induction of systemic immune and clinical responses to such approaches and preclinical models have suggested ways to further potentiate the translation of in situ vaccine trials for our patients.

High serum miR-183 level is associated with poor responsiveness of renal cancer to natural killer cells

Renal cell carcinoma (RCC) is among the most common subtype of kidney cancers, and the current therapeutic strategies are not efficient. Natural killer (NK) cells are biological agents that can induce apoptosis in a wide range of cancer cells. However, most of RCC patients exhibit resistance against the action of NK cells due to unknown mechanisms. This study is aimed to identify a biomarker that can predict the response of RCC cells to NK cell treatment. We collected 82 RCC patients and 19 healthy volunteers to detect the expression of miR-183 in blood by qPCR assays. The results revealed that serum miR-183 is significantly higher in RCC patients than in healthy controls, and its level is positively associated with the grading of RCC. Furthermore, (51)Cr release assays indicated that the primary RCC cells with low serum miR-183 expression are more sensitive to the cytotoxicity of NK cells. Collectively, we demonstrated that serum miR-183 can be used to predict the response of RCC cells to the cytotoxicity induced by NK cells.

Trial watch: DNA vaccines for cancer therapy

The foundation of modern vaccinology dates back to the 1790s, when the English physician Edward Jenner uncovered the tremendous medical potential of prophylactic vaccination. Jenner’s work ignited a wave of nationwide vaccination campaigns abating the incidence of multiple life-threatening infectious diseases and culminating with the eradication of natural smallpox virus, which was definitively certified by the WHO in 1980. The possibility of using vaccines against cancer was first proposed at the end of the 19th century by Paul Ehrlich and William Coley. However, it was not until the 1990s that such a hypothesis began to be intensively investigated, following the realization that the immune system is not completely unresponsive to tumors and that neoplastic cells express immunogenic tumor-associated antigens (TAAs). Nowadays, anticancer vaccines are rapidly moving from the bench to the bedside, and a few prophylactic and therapeutic preparations have already been approved by FDA for use in humans. In this setting, one interesting approach is constituted by DNA vaccines, i.e., TAA-encoding circularized DNA constructs, often of bacterial origin, that are delivered to patients as such or by means of specific vectors, including (but not limited to) liposomal preparations, nanoparticles, bacteria and viruses. The administration of DNA vaccines is most often performed via the intramuscular or subcutaneous route and is expected to cause (1) the endogenous synthesis of the TAA by myocytes and/or resident antigen-presenting cells; (2) the presentation of TAA-derived peptides on the cell surface, in association with MHC class I molecules; and (3) the activation of potentially therapeutic tumor-specific immune responses. In this Trial Watch, we will summarize the results of recent clinical trials that have evaluated/are evaluating DNA vaccines as therapeutic interventions against cancer.

Selective expression of tumor necrosis factor-related apoptosis-inducing ligand mediated by microRNA suppresses renal carcinoma growth

Renal cell carcinoma (RCC) is the most common types among kidney cancers. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) strongly induces apoptosis in RCC. However, TRAIL therapy also leads to hepatotoxicity. To improve the biosafety, we inserted miRNA response elements (MREs) of miR-138, miR-199, and miR-122 into an adenoviral vector, Ad-TRAIL-3MREs, to restrict TRAIL expression within RCC cells. Luciferase assays showed that MREs can regulate the expression of exogenous gene in RCC cells. Ad-TRAIL-3MREs selectively expressed TRAIL and induce apoptosis in RCC cells, but not in normal cells. MTT assays revealed that Ad-TRAIL-3MREs reduced viability of RCC cells without cytotoxicity to normal cells. Ad-TRAIL-3MREs suppressed the growth of ACHN tumors and exerted no hepatotoxicity in vivo. Collectively, we generated a TRAIL-expressing adenoviral vector under the regulation of MREs. This miRNA-based gene therapy may be a promising strategy for RCC treatment.

Trial Watch: DNA vaccines for cancer therapy

During the past 2 decades, the possibility that preparations capable of eliciting tumor-specific immune responses would mediate robust therapeutic effects in cancer patients has received renovated interest. In this context, several approaches to vaccinate cancer patients against their own malignancies have been conceived, including the administration of DNA constructs coding for one or more tumor-associated antigens (TAAs). Such DNA-based vaccines conceptually differ from other types of gene therapy in that they are not devised to directly kill cancer cells or sensitize them to the cytotoxic activity of a drug, but rather to elicit a tumor-specific immune response. In spite of an intense wave of preclinical development, the introduction of this immunotherapeutic paradigm into the clinical practice is facing difficulties. Indeed, while most DNA-based anticancer vaccines are well tolerated by cancer patients, they often fail to generate therapeutically relevant clinical responses. In this Trial Watch, we discuss the latest advances on the use of DNA-based vaccines in cancer therapy, discussing the literature that has been produced around this topic during the last 13 months as well as clinical studies that have been launched in the same time frame to assess the actual therapeutic potential of this intervention.

TG1042 (Adenovirus-interferon-γ) in primary cutaneous B-cell lymphomas: a phase II clinical trial

Rational

While a variety of registered therapies exist for Cutaneous T Cell Lymphoma, no such therapy is available for Cutaneous B Cell Therapy. In this context we performed a phase II, open label, multicenter, non-comparative study to evaluate the efficacy and safety of repeated intra-lesional administrations of TG1042 (adenovirus-interferon-γ) in patients with relapsing primary cutaneous B-cell lymphomas (CBCL).

Method

Thirteen patients have been enrolled and received intralesional injections of TG1042 containing 5×10¹⁰ viral particles into up to six lesions simultaneously. Injections were performed on days 1, 8 and 15 of each of four consecutive 28 day cycles.

Results

Eleven (85%) out of 13 enrolled patients showed an objective response after injections of TG1042. Seven patients (54%) exhibited complete and four (31%) displayed partial response. The median time to disease progression in the study population was 23.5 months (range 6.25 to 26+). Most commonly observed adverse events were minor to moderate flu-like symptoms, fatigue and injection site reactions.

Conclusions

Our study showed that treatment with TG1042 was associated with a clinical benefit in the majority of the patients with relapsing CBCL, including tumor regression, a clinically meaningful duration of response and a good treatment tolerance.

Trial Registration

www.clinicaltrials.govNCT00394693

Antitumor activity of tumor-targeted RNA replicase-based plasmid that expresses interleukin-2 in a murine melanoma model

Double-stranded RNA (dsRNA) has multiple antitumor mechanisms that may be used to control tumor growth. Previously we have shown that treatment of solid tumors with a plasmid that encodes Sindbis viral RNA replicase complex, pSIN-β, significantly inhibited the growth of tumors in mice. In the present study, we evaluated the feasibility of further improving the antitumor activity of the pSIN-β plasmid by incorporating interleukin-2 (IL2) gene into the plasmid. The resultant pSIN-IL2 plasmid was delivered to mouse melanoma cells that overexpress the sigma receptor. Here we report that the pSIN-IL2 plasmid was more effective at controlling the growth of B16 melanoma in mice when complexed with sigma receptor-targeted liposomes than with the untargeted liposomes. Importantly, the pSIN-IL2 plasmid was more effective than pSIN-β plasmid at controlling the growth of B16 melanoma in mice, and B16 tumor-bearing mice that were treated with pSIN-IL2 had an elevated number of activated CD4(+), CD8(+), and natural killer cells, as compared to those treated with pSIN-β. The RNA replicase-based, IL2-expressing plasmid may have applications in melanoma gene therapy.

Toxicological effects of cationic nanobubbles on the liver and kidneys: biomarkers for predicting the risk

Nanobubbles with acoustical activity are used as both diagnostic and therapeutic carriers for detecting and treating diseases. We aimed to prepare nanobubbles and assess toxic responses to them in the liver and kidneys. The cytotoxicity of nanobubbles was determined by examining the viability of liver (HepG2) and kidney (293T) cell lines after a 24-h treatment at various concentrations (0.01-2%). Toxic effects of different formulations were compared by determining functional markers such as γ-glutamyl transferase (γ-GT) and blood urea nitrogen (BUN) after intravenous administration of nanobubbles. Cationic nanobubbles caused concentration-dependent cytotoxicity against cultured cells with a more significant effect in the liver than in the kidneys. A significant reduction of viability was revealed at a concentration as low as 0.1%. Cational systems with soyaethyl morpholinium ethosulfate (SME) exhibited the greatest γ-GT level at 6-fold higher than the control. Immunohistochemistry detected liver fibrosis and inflammation with nanobubbles treatment, especially SME-containing ones at higher doses. According to plasma proteomic profiles, gelsolin and fetuin-B were significantly downregulated 3-fold in the high-dose SME-treated group. Transthyretin decreased by 6-fold in this group. The fibrinogen gamma chain expression was highly elevated. The results suggest that these protein biomarkers are sensitive for assessing the risk of nanobubble exposure. This study is the first to systematically evaluate the possible toxicity of nanobubbles in the liver and kidneys.

Phase II Trial of Dolastatin-10, a Novel Anti-Tubulin Agent, in Metastatic Soft Tissue Sarcomas

PATIENTS

Soft tissue sarcomas are uncommon malignancies with few therapeutic options for recurrent or metastatic disease. Dolastatin-10 (Dol-10) is a pentapeptide anti-microtubule agent that binds to tubulin sites distinct from vinca alkaloids. Based on the novel mechanism of action, limited activity of other anti-microtubular agents, and anti-neoplastic activity in pre-clinical screening of Dol-10, this multi-institutional phase II study was conducted to determine the objective response rate of Dol-10 in recurrent or metastatic soft tissue sarcomas that had not been treated with chemotherapy outside of the adjuvant setting.

METHODS

Dol-10 was given intravenously at a dose of 400 mug/m(2) and repeated every 21 days. Toxicities were assessed using the Common Toxicity Criteria (version 2.0). Radiographic studies and tumor measurements were repeated every two cycles to assess response [Miller AB, et al. Cancer 1981; 47(1): 207].

RESULTS

Dol-10 was associated with hematological toxicity and with some vascular toxicities. There was no significant gastrointestinal, hepatic or renal toxicity. There was one death on study due to respiratory failure. There were no objective responses in 12 patients treated with Dol-10.

DISCUSSION

Based on this phase II trial, further study of Dol-10 on this schedule is not recommended in advanced or metastatic soft tissue sarcomas.

Effective melanoma immunotherapy with interleukin-2 delivered by a novel polymeric nanoparticle

Interleukin-2 (IL-2) has been shown to possess antitumor activity in numerous preclinical and clinical studies. However, the short half-life of recombinant IL-2 protein in serum requires repeated high-dose injections, resulting in severe side effects. Although adenovirus-mediated IL-2 gene therapy has shown antitumor efficacy, the host antibody response to adenoviral particles and potential biosafety concerns still obstruct its clinical applications. Here we report a novel nanopolymer for IL-2 delivery, consisting of low molecular weight polyethylenimine (600 Da) linked by β-cyclodextrin and conjugated with folate (named H1). H1 was mixed with IL-2 plasmid to form H1/pIL-2 polyplexes of around 100 nm in diameter. Peritumoral injection of these polyplexes suppressed the tumor growth and prolonged the survival of C57/BL6 mice bearing B16-F1 melanoma grafts. Importantly, the antitumor effects of H1/pIL-2 (50 μg DNA) were similar to those of recombinant adenoviruses expressing IL-2 (rAdv-IL-2; 2 × 10(8) pfu). Furthermore, we showed that H1/pIL-2 stimulated the activation and proliferation of CD8+, CD4+ T cell, and natural killer cells in peripheral blood and increased the infiltration of CD8+, CD4+ Tcells, and natural killer cells into the tumor environment. In conclusion, these results show that H1/pIL-2 is an effective and safe melanoma therapeutic with an efficacy comparable to that of rAdv-IL-2. This treatment represents an alternative gene therapy strategy for melanoma.

Synthetic vehicles for DNA vaccination

DNA vaccination is an attractive immunization method able to induce robust cellular immune responses in pre-clinical models. However, clinical DNA vaccination trials performed thus far have resulted in marginal responses. Consequently, strategies are currently under development to improve the efficacy of DNA vaccines. A promising strategy is the use of synthetic particle formulations as carrier systems for DNA vaccines. This review discusses commonly used synthetic carriers for DNA vaccination and provides an overview of in vivo studies that use this strategy. Future recommendations on particle characteristics, target cell types and evaluation models are suggested for the potential improvement of current and novel particle delivery systems. Finally, hurdles which need to be tackled for clinical evaluation of these systems are discussed.

Phase I trial of interleukin-12 plasmid electroporation in patients with metastatic melanoma

PURPOSE

Gene-based immunotherapy for cancer is limited by the lack of safe, efficient, reproducible, and titratable delivery methods. Direct injection of DNA into tissue, although safer than viral vectors, suffers from low gene transfer efficiency. In vivo electroporation, in preclinical models, significantly enhances gene transfer efficiency while retaining the safety advantages of plasmid DNA.

PATIENTS AND METHODS

A phase I dose escalation trial of plasmid interleukin (IL)-12 electroporation was carried out in patients with metastatic melanoma. Patients received electroporation on days 1, 5, and 8 during a single 39-day cycle, into metastatic melanoma lesions with six 100-mus pulses at a 1,300-V/cm electric field through a penetrating six-electrode array immediately after DNA injection. Pre- and post-treatment biopsies were obtained at defined time points for detailed histologic evaluation and determination of IL-12 protein levels.

RESULTS

Twenty-four patients were treated at seven dose levels, with minimal systemic toxicity. Transient pain after electroporation was the major adverse effect. Post-treatment biopsies showed plasmid dose proportional increases in IL-12 protein levels as well as marked tumor necrosis and lymphocytic infiltrate. Two (10%) of 19 patients with nonelectroporated distant lesions and no other systemic therapy showed complete regression of all metastases, whereas eight additional patients (42%) showed disease stabilization or partial response.

CONCLUSION

This report describes the first human trial, to our knowledge, of gene transfer utilizing in vivo DNA electroporation. The results indicated this modality to be safe, effective, reproducible, and titratable.

[Development of nucleic acid transfection technology to the kidney]

The kidney is one of the most important organs that play a crucial role in homeostasis and, therefore, congenital or acquired renal dysfunction causes refractory diseases, i.e., Alport's syndrome, Fabry's disease, diabetic nephropathy, IgA nephropathy, kidney cancer, transplant glomerulopathy. Nucleic acid transfection technology to the kidney is indispensable for the progress of biomedical research and the realization of gene therapy and nucleic acid drug for renal diseases. Control of renal nucleic acid transfection was difficult because of the structural complexity; however, the study of recombinant virus, synthetic carrier and physical force-mediated nucleic acid transfection to the kidney has advanced. Recombinant virus and synthetic carrier-mediated methods require long-term block of the blood or urinary flow for efficient transfection of nucleic acid because of the rich blood flow of the kidney. In contrast, physical force-mediated methods that transfect with nucleic acid via transient membrane permeability do not apprehend ischemia-reperfusion injury and, therefore, may be beneficial for nucleic acid transfection to the kidney. In this article, we collect the information of therapeutic gene, target molecule of the nucleic acid drug and target cells for renal diseases and structural property of the kidney from the point of view of nucleic acid transfection. Additively, current status of nucleic acid transfection technology to the kidney is reviewed.

Vaxfectin™ enhances immunogenicity and protective efficacy of P. yoelii circumsporozoite DNA vaccines

We evaluated the capacity of the cationic lipid based formulation, Vaxfectin, to enhance the immunogenicity and protective efficacy of DNA-based vaccine regimens in the Plasmodium yoelii murine malaria model. We immunized Balb/c mice with varying doses (0.4-50 microg) of plasmid DNA (pDNA) encoding the P. yoelii circumsporozoite protein (PyCSP), either in a homologous DNA/DNA regimen (D-D) or a heterologous prime-boost DNA-poxvirus regimen (D-V). At the lowest pDNA doses, Vaxfectin substantially enhanced IFA titers, ELISPOT frequencies, and protective efficacy. Clinical trials of pDNA vaccines have often used low pDNA doses based on a per kilogram weight basis. Formulation of pDNA vaccines in Vaxfectin may improve their potency in human clinical trials.

Adult soft tissue sarcomas: Conventional therapies and molecularly targeted approaches

The therapeutic approach to soft tissue sarcomas (STS) has evolved over the past two decades based on the results from randomized controlled trials, which are guiding physicians in the treatment decision-making process. Despite significant improvements in the control of local disease, a significant number of patients ultimately die of recurrent/metastatic disease following radical surgery due to a lack of effective adjuvant treatments. In addition, the characteristic chemoresistance of STS has compromised the therapeutic value of conventional antineoplastic agents in cases of unresectable advanced/metastatic disease. Therefore, novel therapeutic strategies are urgently needed to improve the prognosis of patients with STS. Recent advances in STS biology are paving the way to the development of molecularly targeted therapeutic strategies, the efficacy of which relies not only on the knowledge of the molecular mechanisms underlying cancer development/progression but also on the personalization of the therapeutic regimen according to the molecular features of individual tumours. In this work, we review the state-of-the-art of conventional treatments for STS and summarize the most promising findings in the development of molecularly targeted therapeutic approaches.

The evolving role of gene-based treatment in surgery

Background

The completion of the sequencing of the human genome in 2003 marked the dawn of a new era of human biology and medicine. Although these remarkable scientific advances improve the understanding of human biology, the question remains how this rapidly expanding knowledge of functional genomics affects the role of surgeons. This article reviews the potential therapeutic application of gene therapy for various surgical conditions.

Methods

The core of this review was derived from a Medline database literature search.

Results and conclusion

The currently available vectors in the field of gene therapy and their limitations for clinical applications were analysed. The achievements of gene therapy in clinical trials and the future ramifications for surgery were also explored. Whether gene therapy takes a major role in surgical practice will depend greatly on the success of future vector development. Advances in viral vector technology to reduce the inflammatory effect, and improvements in the efficiency of gene delivery using non-viral vector technology, would allow this form of therapy to become more clinically applicable.

Cationic lipids with increased DNA binding affinity for nonviral gene transfer in dividing and nondividing cells

Effect of headgroup structure on catonic lipid-mediated transfection was investigated with either a (i) tertiary amine, (ii) quaternary amine with a hydroxyl, or (iii) quaternary amine with mesylate as headgroups. Liposomes were formulated using cholesterol or dioleoyl phosphatidyl ethanolamine (DOPE) as colipids, and transfection efficiencies were determined in rapidly dividing colon carcinoma (CT 26) and rat aortic smooth muscle (RASM) cells as well as in nondividing human pancreatic islets using luciferase and green fluorescent protein expression plasmids, pcDNA3-Luc and pCMS-EGFP, respectively. Liposome/pDNA complexes were evaluated for DNA conformational state by circular dichroism (CD), DNA condensation by electrophoretic mobility shift assay (EMSA), particle size and zeta potential by laser diffraction technique, and surface morphology by transmission electron microscopy (TEM). Encouraging transfection results were obtained with the mesylate headgroup based lipid in liposome formulations with DOPE as a colipid, which were higher than the commercially available Lipofectamine formulation. We hypothesize that the additional hydrogen bonding or covalent interactions of the headgroup with the plasmid DNA, leading to higher binding affinity of the cationic lipids to pDNA, results in higher transfection. This hypothesis is supported by TEM observations where elongated complexes were observed and more lipid was seen associated with the DNA.

Phase I-II trial of ONYX-015 in combination with MAP chemotherapy in patients with advanced sarcomas

ONYX-015 is a provisionally replication competent adenovirus with oncolytic activity in cells with malfunctioning p53. Sarcomas represent a rational target for this approach given the high frequency of p53 mutations (40-75%) and MDM-2 amplification (10-30%). We, therefore, undertook a phase I/II study of ONYX-015, days 1-5 every month administered intratumorally under radiographic guidance, in combination with MAP (mitomycin-C, doxorubicin, cisplatin) chemotherapy in patients with advanced sarcoma. Six patients were treated. Injected lesions included liver metastases in four patients and chest wall metastases in two patients. Sarcoma histologies were gastrointestinal stromal tumors (GIST, two patients), leiomyosarcoma (two patients), liposarcoma (one patient), and malignant peripheral nerve sheath tumor (1 patient). Dose escalation was performed from 10(9) plaque forming units (PFU)/dose (total dose of 5 x 10(9) PFU/cycle) to 10(10) PFU/dose (total dose of 5 x 10(10) PFU/cycle) without dose-limiting toxicity being encountered. Immunohistochemistry of the metastatic lesions prior to treatment showed that five out of six patients were positive for p53, while two patients also had mdm-2 overexpression. Adenoviral replication was detected in two out of six patient biopsies on day 5 of the first cycle, by in situ hybridization (ISH). Both patients were treated at the highest dose level. ONYX-015 viral DNA was detected by quantitative PCR in the plasma of 5/6 patients on day 5 of the first cycle, and up to day 12 (7 days after the last viral dose) in one patient who had extended sampling for viral kinetics performed, suggesting viral replication in sarcoma tissue. One patient with p53 mutation and MDM-2 amplification achieved a partial response to treatment that lasted 11 months. In conclusion, intratumoral administration of ONYX-015 in combination with MAP chemotherapy is well tolerated with no significant toxicity due to ONYX-015 being encountered. Detection of viral DNA in post treatment tumor specimens by ISH and detection of the ONYX-015 genome in the peripheral blood by quantitative PCR, up to 7 days after the last viral dose provide evidence for adenoviral replication. There was evidence of antitumor activity in one out of six patients. Further investigation of this approach in patients with recurrent sarcomas is warranted.

Gene therapy for head and neck cancer

The prognosis of patients with advanced head and neck cancer has not changed significantly in the last twenty years, despite concerted efforts to optimize treatment using conventional modalities such as surgery, radiotherapy and chemotherapy. Novel therapeutic approaches based on our increasing understanding of the molecular changes that underlie the development of cancer have the potential to alter this situation. Gene therapy involves the delivery of genetic sequences in to tumour or normal cells for a therapeutic purpose. A number of viral and non-viral vectors have been developed that have the ability to deliver therapeutic genes specifically to tumours. These therapeutic genes can exert their effects by correcting existing genetic abnormalities, by killing cells directly or indirectly through recruitment of the immune system. In this review, the various gene therapy strategies that are under development are presented with particular reference to the treatment of head and neck cancer.

Plasmid vaccines and therapeutics: from design to applications

In the late 1980s, Vical and collaborators discovered that the injection into tissues of unformulated plasmid encoding various proteins resulted in the uptake of the plasmid by cells and expression of the encoded proteins. After this discovery, a period of technological improvements in plasmid delivery and expression and in pharmaceutical and manufacturing development was quickly followed by a plethora of human clinical trials testing the ability of injected plasmid to provide therapeutic benefits. In this chapter, we summarize in detail the technologies used in the most recent company-sponsored clinical trials and discuss the potential for future improvements in plasmid design, manufacturing, delivery, formulation and administration. A generic path for the clinical development of plasmid-based products is outlined and then exemplified using a case study on the development of a plasmid vaccine from concept to clinical trial.

Intratumoral administration of a 1,2-dimyristyloxypropyl-3- dimethylhydroxyethyl ammonium bromide/dioleoylphosphatidylethanolamine formulation of the human interleukin-2 gene in the treatment of metastatic renal cell carcinoma

BACKGROUND

Leuvectin (Vical Inc., San Diego, CA) is a gene transfer product in which a plasmid encoding the human interleukin-2 (IL-2) gene is complexed with the cationic lipid 1,2-dimyristyloxypropyl-3-dimethylhydroxyethyl ammonium bromide/dioleoylphosphatidylethanolamine (DMRIE/DOPE). In the current study, the authors investigated the safety and efficacy of in situ vaccination with Leuvectin in patients with metastatic renal cell carcinoma.

METHODS

Thirty-one patients with metastatic renal cell carcinoma were treated with intratumorally administered Leuvectin at doses ranging from 0.75 to 4 mg. These patients subsequently were evaluated for response and for treatment-related toxicity.

RESULTS

Treatment was well tolerated: no Grade 3 or 4 toxicities were observed in association with the study agent. Documented side effects included Grade 1 pain at the injection site (20%); mild (i.e., Grade 1 or 2) constitutional symptoms, including malaise/myalgia, low-grade fever, and chills (74%); Grade 1 fatigue (19%); Grade 1 or 2 nausea (10%); and Grade 2 allergy (1 occurrence). Two patients experienced partial responses, which endured for 32 months and 6 years, respectively, and 1 patient currently is experiencing a pathologic complete response, which, to date, has persisted for 50 months; thus, the overall response rate was 10%. In addition, 7 patients (23%) experienced disease stabilization for a median of 8 months (range, 4-48 months). The median duration of survival from the start of Leuvectin treatment was 11 months (range, 2-72 months), with a 1-year survival rate of 48% and a 3-year survival rate of 19%. Laboratory analysis of tumor samples revealed the presence of IL-2 plasmid DNA in six of eight patients posttreatment, increased IL-2 expression in tumor cells in four of eight patients posttreatment, and increased tumor infiltration by CD8-positive lymphocytes in five of eight patients posttreatment.

CONCLUSIONS

Immunotherapy with intratumorally administered Leuvectin is safe and can lead to durable objective responses in patients with metastatic renal cell carcinoma.

Metastatic renal cell carcinoma: CT-guided immunotherapy as a technically feasible and safe approach to delivery of gene therapy for treatment

PURPOSE

To assess the technical feasibility and safety of weekly outpatient percutaneous computed tomographic (CT)-guided intratumoral injections of interleukin-2 (IL-2) plasmid DNA in a wide variety of superficial and deep tumor sites.

MATERIALS AND METHODS

Twenty-nine patients with metastatic renal cell carcinoma and a total of 30 lesions measuring 1.0 cm(2) or greater in accessible thoracic (n = 15) or abdominal (n = 15) locations underwent up to three cycles of six weekly intratumoral IL-2 plasmid DNA injections. CT was used to guide needle placement and injection. After injection cycle 1, patients whose tumors demonstrated stable (< or =25% increase and < or =50% decrease in product of lesion diameters) or decreased size (>50% decrease in product of lesion diameters) advanced to injection cycle 2. Patients whose lesions decreased in size by more than 50% over the course of injection cycle 2 were eligible to begin injection cycle 3. An acceptable safety and technical feasibility profile for this technique was deemed to be (a) a safety and feasibility profile similar to that of single-needle biopsy and (b) an absence of serious adverse events (as defined in Title 21 of the Code of Federal Regulations) and/or unacceptable toxicities (as graded according to the National Cancer Institute Common Toxicity Criteria).

RESULTS

A total of 284 intratumoral injections were performed, with a mean of 9.8 injections (range, 6-18 injections) received by each patient. Technical success (needle placement and injection of gene therapy agent) was achieved in all cases. Complications were experienced after 42 (14.8%) of the 284 injections. The most common complication was pneumothorax (at 32 [28.6%] of 112 intrathoracic injections), for which only one patient required catheter drainage. Complications occurred randomly throughout injection cycles and did not appear to increase as patients received more injections (P =.532). No patient experienced serious adverse events or unacceptable toxicities.

CONCLUSION

Percutaneous CT-guided intratumoral immunotherapy injections are technically feasible and can be safely performed.

Endocrine aspects of cancer gene therapy

The field of cancer gene therapy is in continuous expansion, and technology is quickly moving ahead as far as gene targeting and regulation of gene expression are concerned. This review focuses on the endocrine aspects of gene therapy, including the possibility to exploit hormone and hormone receptor functions for regulating therapeutic gene expression, the use of endocrine-specific genes as new therapeutic tools, the effects of viral vector delivery and transgene expression on the endocrine system, and the endocrine response to viral vector delivery. Present ethical concerns of gene therapy and the risk of germ cell transduction are also discussed, along with potential lines of innovation to improve cell and gene targeting.

Perspectives for gene therapy in renal diseases

Somatic cell gene therapy has made considerable progress last five years and has shown clear success in some clinical trials. In the field of nephrology, both the elucidation of pathophysiology of renal diseases and the development of gene transfer technique have become driving force for new therapy of incurable renal diseases, such as Alport syndrome and polycystic kidney disease. Gene therapy of renal cancer, although its application is limited to advanced cancer, is the front-runner of clinical application. Erythropoietin gene therapy has provided encouraging results for the treatment of anemia in uremic rats and recently progressed to the inducible one in response to hypoxia. Gene therapy for glomerulonephritis and renal fibrosis showed prominent impact on experimental models, although the safety must be confirmed for prolonged treatment. Transplant kidney is an ideal material for gene modification and induction of tolerance in the transplant kidney is an attractive challenge. Emerging techniques are becoming available such as stem cell technology and messenger RNA silencing strategies. We believe that the future of gene therapy research is exciting and promising and it holds an enormous potential for clinical application.

Phase II Trial of Dolastatin-10, a Novel Anti-Tubulin Agent, in Metastatic Soft Tissue Sarcomas

PATIENTS

Soft tissue sarcomas are uncommon malignancies with few therapeutic options for recurrent or metastatic disease. Dolastatin-10 (Dol-10) is a pentapeptide anti-microtubule agent that binds to tubulin sites distinct from vinca alkaloids. Based on the novel mechanism of action, limited activity of other anti-microtubular agents, and anti-neoplastic activity in pre-clinical screening of Dol-10, this multi-institutional phase II study was conducted to determine the objective response rate of Dol-10 in recurrent or metastatic soft tissue sarcomas that had not been treated with chemotherapy outside of the adjuvant setting.

METHODS

Dol-10 was given intravenously at a dose of 400 mug/m(2) and repeated every 21 days. Toxicities were assessed using the Common Toxicity Criteria (version 2.0). Radiographic studies and tumor measurements were repeated every two cycles to assess response [Miller AB, et al. Cancer 1981; 47(1): 207].

RESULTS

Dol-10 was associated with hematological toxicity and with some vascular toxicities. There was no significant gastrointestinal, hepatic or renal toxicity. There was one death on study due to respiratory failure. There were no objective responses in 12 patients treated with Dol-10.

DISCUSSION

Based on this phase II trial, further study of Dol-10 on this schedule is not recommended in advanced or metastatic soft tissue sarcomas.

Prospects and RISC score of viral gene therapy for sarcoma

Soft tissue sarcomas are a challenge for medical oncology and gene therapy. Protective and sensitising approaches that target normal and malignant tissue, respectively, both have their role for opening the therapeutic window. Recent data show that an intensive maintenance chemotherapy significantly reduces metastatic spread and improves disease-free survival in selected patient groups. However, delays of treatment due to cytopenia are frequent. Cytostatic drug resistance gene transfer to haematopoietic progenitor cells using retroviral vectors may allow further improvement of therapy results. In recent years, retroviral vector design, transduction techniques and engraftment capability of transduced cells have been optimised. Safety considerations of retroviral gene transfer have attracted public attention and can be addressed by analysis of genomic vector integration sites. A data bank project, 'retroviral insertion estimate of chromosomal integration' (RISC), containing > 200 integration sequences, has been set up by the authors' group to recognise critical genomic regions and genes involved with possible transforming capacity. Monitoring these parameters will allow the selection of the most suitable vectors for clinical application. Sarcoma cells seem to be highly susceptible to a variety of vectors, such as recombinant adeno-associated virus-2 (rAAV-2) vectors, adenoviral vectors or oncolytic herpes simplex viruses. Results from the first clinical trials with adenoviral vectors encoding for cytokines are promising. The other systems await further development towards clinical applications. Perspectives for further research are discussed in this review.

Clinical development of gene therapy for colorectal cancer

Colorectal cancer (CRC) is the second most common type of malignancy in Western nations. Improvements in surgical and radiotherapeutic techniques and the increased availability of new cytotoxic drugs have improved outcome, but 50% of patients still die from recurrent or metastatic disease. Several features of its natural history render CRC a good candidate for gene therapy. Techniques include gene replacement, virus-directed enzyme-prodrug therapy, immune manipulation and virotherapy, all of which have entered clinical trials.

Gene therapy for colorectal cancer

Colorectal cancer is an important public health problem worldwide. Gene therapy has therapeutic potential for patients with advanced or recurrent colorectal cancer, incurable by conventional treatments. To date, many strategies of gene therapy have been explored, including mutant gene correction, prodrug activation, immune stimulation and genetically-modified oncolytic viruses. Although the preclinical results of gene therapy for colorectal cancer have shown promise, gene therapy is still at an early stage of clinical development and has not yet shown a significant therapeutic benefit for patients. The main obstacles for introduction of gene therapy to patients are poor targeting selectivity of the vectors and inefficient gene transfer. As the science supporting tumour-selective vectors evolves, gene therapy may expand rapidly in the clinical practice of colorectal cancer treatment.

[Gene therapy of melanoma: review of published clinical trials]

INTRODUCTION

Melanoma frequency increases. Conventional antitumoral treatments fail. Gene therapy for metastatic melanoma is studied in 17 phase I-II clinical trials. ACTUALITES ET POINTS FORTS: Sixteen use cytokine genes. These studies are heterogenous as far as methodology is concerned. Gene therapy clinical tolerance is acceptable. Security is rarely discuted. In these studies overall response rate is 8%, with histological complete responses.

PERSPECTIVES

Presently, three new studies are opened in United States.

Immunotherapy for renal cell carcinoma

Renal cell carcinoma (RCC) is the most prevalent malignancy within the kidney and the incidence is rising. Due to improved radiological evaluation over 50% of the renal cancers are found incidentally. Despite the fact that these incidentalomas are often confined to the kidney, around 50% of all patients diagnosed with kidney cancer will develop systemic disease. Metastatic RCC has a poor prognosis. Traditional treatment modalities like chemo- and radiotherapy show overall response percentages of 2-6%. In view of the observed spontaneous remissions of advanced renal cancer, immune mechanisms have been suggested to play a role in the natural disease course of RCC. At present, several non-specific cytokine regimens are used in the treatment of mRCC, e.g. interleukin-2 and interferon-alpha, in combination or as monotherapy or in combination with substances like 13-cis-retinoic acid and/or 5-fluorouracil. Collective data of trials evaluating cytokine-based therapies for mRCC show an overall response rate of approximately 15%, with 5% of the patients showing complete responses. More importantly, cytokine treatment clearly translates into a significant survival benefit in a subset of patients. Nevertheless, the toxicity profile of these cytokine regimens is significant. With the enhanced knowledge of tumor-immunology, the identification of immunogenic tumor proteins, and antibodies recognizing tumor-associated antigens, new treatment strategies with increased specificity and fewer side effects are of interest. Here we review the different immunotherapeutical modalities currently used as well as new approaches for the treatment of advanced RCC.

IL-2 gene and antisense TGF-beta1 strategies counteract HSV-2 transformed tumor progression

The H238 tumor cells are Herpes simplex virus type 2-transformed BALB/c mouse fibroblasts that constitutively express transforming growth factor (TGF-beta1). TGF-beta can diminish immune capacity, whereas interleukin 2 (IL-2) is stimulatory to the immune system and can counteract the negative effects of TGF-beta1. The H238-BALB/c system provides a syngeneic model to evaluate new strategies with the potential to ameliorate tumor-induced immune depression. Plasmids expressing either antisense TGF-beta1 or murine Il-2 were constructed and stably transformed cells generated (masH238 and H238-IL2, respectively). In vitro measurements (ELISA and RT-PCR) demonstrated a >70% decrease in TGF-beta1 secretion by the masH238 tumor cells, and significant levels of IL-2 production by the H238-IL2 transfected cells when compared to wild type and control plasmid-transfected H238 cells. BALB/c mice injected subcutaneously with the masH238 cells developed significantly smaller tumors than the controls. Mice injected with H238-IL-2 cells developed tumors that failed to progress relative to control tumor growth. The differences in tumor growth in the mice were associated with enhanced immune reactivity and an increased response to T lymphocyte mitogens. Significant differences were also noted in lymphocyte populations and expression of CD25 and CD71 activation markers in the blood and spleens of mice receiving transfected tumor cells. Collectively, the data demonstrate that strategies employing antisense TGF-beta1 and IL-2 expression by transfected tumor cells can counteract the progression of a TGF-beta1-secreting tumor and enhance immune function involving modulation of T lymphocyte populations.

Non-viral and hybrid vectors in human gene therapy: an update

Non-viral DNA vectors have several advantages over viral vectors. For example, virus production is expensive and there are safety concerns regarding viral manipulations. In addition, the size of the delivered plasmid is limited by the size of the viral capsid, whereas this is not a problem with non-viral vectors. The major disadvantage of using non-viral DNA delivery vectors, compared with their viral counterparts, is the low transfection efficiency. This has resulted in low levels of usage in clinical trials. Consequently, the majority of research into non-viral gene therapy has been focused on developing more efficient vectors.

Gene-based immunotherapy of skin cancers

Skin cancers continue to present a major therapeutic challenge to physicians. Recent advances in molecular genetics and improved understanding of immune responses to tumors have generated an interest in using gene-based immunotherapy for treating these malignancies. Two major forms of gene-based immunotherapy are currently being investigated. One focuses on genetic modification of some target cell populations of the host using immunostimulatory genes such as cytokines, in order to improve tumor immunogenicity and antitumor responses; the other is genetic immunization with the genes coding for melanoma-associated antigens recognized by cytotoxic T cells. This paper reviews these novel strategies and summarizes the most recent data recorded in either experimental studies or clinical trials.

In vivo characteristics of cationic liposomes as delivery vectors for gene therapy

After a decade of clinical trials, gene therapy seems to have found its place between excessive ambitions and feasible aims, with encouraging results obtained in recent years. Intracellular delivery of genetic material is the key step in gene therapy. Optimization of delivery vectors is of major importance for turning gene therapy into a successful therapeutic method. Nonviral gene delivery relies mainly on the complexes formed from cationic liposomes (or cationic polymers) and DNA, i.e., lipoplexes (or polyplexes). Many lipoplex formulations have been studied, but in vivo activity is generally low compared to that of viral systems. This review gives a concise overview of studies on the application of cationic liposomes in vivo in animal models of diseases and in clinical studies. The transfection efficiency, the pharmacokinetic and pharmacodynamic properties of the lipid-DNA complexes, and potentially relevant applications for cationic liposomes are discussed. Furthermore, the toxicity of, and the induction of an inflammatory response in association with the administration of lipoplexes are described. Increasing understanding of lipoplex behavior and gene transfer capacities in vivo offers new possibilities to enhance their efficiency and paves the path to more extensive clinical applications in the future.

Applications of gene transfer to cellular immunotherapy

Adoptive cellular therapy remains a potentially powerful method of eradicating established tumors. T-cells have been particularly potent effector cells, as demonstrated in animal models and clinical studies, and it is apparent that the stimulation of certain subpopulations of T-cells that are reactive to tumor antigens can lead to more therapeutic T-cells. The use of gene transfer techniques has resulted in more effective and specific methods to generate these tumor-specific T-cells. Another area of tremendous interest is in the adoptive transfer of DCs manipulated to present tumor antigen to resting, naive T-cells. Gene transfer techniques may offer more optimal ways to generate therapeutic DCs. Adoptive immunotherapy may ultimately [figure: see text] have its greatest use in patients undergoing cellular rescue after ablative chemotherapy; the infusion of immunocompetent T-cells, genetically modified stem cells, or programmed DCs may offer the opportunity to direct a patient's immune response to eliminate residual microscopic disease.