Enhancement of electroporation facilitated immunogene therapy via T-reg depletion

Basement membranes in lung metastasis growth and progression

The lung is a highly vascularized tissue that often harbors metastases from various extrathoracic malignancies. Lung parenchyma consists of a complex network of alveolar epithelial cells and microvessels, structured within an architecture defined by basement membranes. Consequently, understanding the role of the extracellular matrix (ECM) in the growth of lung metastases is essential to uncover the biology of this pathology and developing targeted therapies. These basement membranes play a critical role in the progression of lung metastases, influencing multiple stages of the metastatic cascade, from the acquisition of an aggressive phenotype to intravasation, extravasation and colonization of secondary sites. This review examines the biological composition of basement membranes, focusing on their core components-collagens, fibronectin, and laminin-and their specific roles in cancer progression. Additionally, we discuss the function of integrins as primary mediators of cell adhesion and signaling between tumor cells, basement membranes and the extracellular matrix, as well as their implications for metastatic growth in the lung. We also explore vascular co-option (VCO) as a form of tumor growth resistance linked to basement membranes and tumor vasculature. Finally, the review covers current clinical therapies targeting tumor adhesion, extracellular matrix remodeling, and vascular development, aiming to improve the precision and effectiveness of treatments against lung metastases.

Acute Effects of Intratumor DNA Electrotransfer

Intratumor therapeutic DNA electroporation or electrotransfer is in clinical trials in the United States and is under development in many other countries. Acute changes in endogenous gene expression in response to DNA or to pulse application may significantly modulate the therapeutic efficacy of the expressed proteins. Oligonucleotide arrays were used in this study to quantify changes in mRNA expression in B16-F10 mouse melanoma tumors four hours after DNA electrotransfer. The data were subjected to the DAVID v6.8 web server for functional annotation to reveal regulated genes and genetic pathways. Gene ontology analysis revealed several molecular functions related to cytoskeletal remodeling and inflammatory signaling. In B16-F10 cells, F-actin remodeling was confirmed by phalloidin staining in cells that received pulse application alone or in the presence of DNA. Chemokine secretion was confirmed in cells receiving DNA electrotransfer. These results indicate that pulse application alone or in the presence of DNA may modulate the therapeutic efficacy of therapeutic DNA electrotransfer.

Inhibition of constructed SEC3-ES lentiviral vector to proliferation, migration of Hela cells

AIM

To construct a lentiviral vector with endostatin (ES) and staphylococcal enterotoxin C₃(SEC3) gene, and investigate its capacities of inhibition on proliferation and migration of Hela cells.

METHODS

By inserting ES and SEC3 gene into the plasmid and then transfect 293 T cell, the co-expressed (SEC3-ES) vector were constructed. A series of experiments in vitro were carried out to detect its anti-tumor capacity.

RESULTS

SEC3 expression of the vector is about 3 times of GV365-SEC3 vector, and ES expression is over 22.5-fold compared with GV365-ES vector. Moreover, OD490 value of CO group (1.212 ± 0.003) was notably lower than NC (negative control) group (1.124 ± 0.01) (P < 0.05) in MTT assay. Cell cycle analysis showed it could block Hela cells in S phase. Meanwhile, in wound healing assay, cells of CO group migrated at a slower rate (0.59 ± 0.02) compared with NC group (0.65 ± 0.02)(P < 0.01).

CONCLUSION

The successful construction of co-expressed vector lays the foundation for further studies in vivo. These promising results suggest a new strategy to treating cervical cancer.

Platelets modulate the immune response following trauma by interaction with CD4+ T regulatory cells in a mouse model

CD4+ T regulatory cells (Tregs) play a pivotal role in the anti-inflammatory immune response following trauma. The mechanisms of CD4+ Treg activation are mostly unknown. Here, we hypothesize that platelets regulate CD4+ Treg activation following trauma. In a murine burn injury model (male C57Bl/6N mice), depletion of platelets or CD4+ Tregs was conducted. Draining lymph nodes, blood and spleen were harvested 2 h and 7 days after trauma. CD4+ Treg activation was measured using phospho- and conventional flow cytometry. Platelet activation was analyzed using thromboelastometry and flow cytometry. Trauma differentially activates CD4+ T cells, early after trauma only CD4+ Tregs are activated. Following burn injury, platelets augment the activation of CD4+ Tregs. This effect could only be seen early after trauma. While CD4+ Tregs influence hemostasis early following trauma, platelet activation markers were unchanged. Beyond their role in hemostasis, platelets are able to modulate the immunologic host response to trauma-induced injury by augmenting the activation of CD4+ Tregs. CD4+ Treg activation following trauma is considered protective. In addition, CD4+ Tregs are capable of modulating the hemostatic function of platelets. For the first time, we could show reciprocal activation of platelets and CD4+ Tregs as part of the protective immune response following trauma.

Bystander Effect Induced by Electroporation is Possibly Mediated by Microvesicles and Dependent on Pulse Amplitude, Repetition Frequency and Cell Type

Bystander effect, a known phenomenon in radiation biology, where irradiated cells release signals which cause damage to nearby, unirradiated cells, has not been explored in electroporated cells yet. Therefore, our aim was to determine whether bystander effect is present in electroporated melanoma cells in vitro, by determining viability of non-electroporated cells exposed to medium from electroporated cells and by the release of microvesicles as potential indicators of the bystander effect. Here, we demonstrated that electroporation of cells induces bystander effect: Cells exposed to electric pulses mediated their damage to the non-electroporated cells, thus decreasing cell viability. We have shown that shedding microvesicles may be one of the ways used by the cells to mediate the death signals to the neighboring cells. The murine melanoma B16F1 cell line was found to be more electrosensitive and thus more prone to bystander effect than the canine melanoma CMeC-1 cell line. In B16F1 cell line, bystander effect was present above the level of electropermeabilization of the cells, with the threshold at 800 V/cm. Furthermore, with increasing electric field intensities and the number of pulses, the bystander effect also increased. In conclusion, electroporation can induce bystander effect which may be mediated by microvesicles, and depends on pulse amplitude, repetition frequency and cell type.

Cytosolic DNA Sensor Upregulation Accompanies DNA Electrotransfer in B16.F10 Melanoma Cells

In several preclinical tumor models, antitumor effects occur after intratumoral electroporation, also known as electrotransfer, of plasmid DNA devoid of a therapeutic gene. In mouse melanomas, these effects are preceded by significant elevation of several proinflammatory cytokines. These observations implicate the binding and activation of intracellular DNA-specific pattern recognition receptors or DNA sensors in response to DNA electrotransfer. In tumors, IFNβ mRNA and protein levels significantly increased. The mRNAs of several DNA sensors were detected, and DAI, DDX60, and p204 tended to be upregulated. These effects were accompanied with reduced tumor growth and increased tumor necrosis. In B16.F10 cells in culture, IFNβ mRNA and protein levels were significantly upregulated. The mRNAs for several DNA sensors were present in these cells; DNA-dependent activator of interferon regulatory factor (DAI), DEAD (Asp-Glu-Ala-Asp) box polypeptide 60 (DDX60), and p204 were significantly upregulated while DDX60 protein levels were coordinately upregulated. Upregulation of DNA sensors in tumors could be masked by the lower transfection efficiency compared to in vitro or to dilution by other tumor cell types. Mirroring the observation of tumor necrosis, cells underwent a significant DNA concentration-dependent decrease in proliferation and survival. Taken together, these results indicate that DNA electrotransfer may cause the upregulation of several intracellular DNA sensors in B16.F10 cells, inducing effects in vitro and potentially in vivo.

The Effect of Millisecond Pulsed Electric Fields (msPEF) on Intracellular Drug Transport with Negatively Charged Large Nanocarriers Made of Solid Lipid Nanoparticles (SLN): In Vitro Study

Drug delivery technology is still a dynamically developing field of medicine. The main direction in nanotechnology research (nanocarriers, nanovehicles, etc.) is efficient drug delivery to target cells with simultaneous drug reduction concentration. However, nanotechnology trends in reducing the carrier sizes to several nanometers limit the volume of the loaded substance and may pose a danger of uncontrolled access into the cells. On the other hand, nanoparticles larger than 200 nm in diameter have difficulties to undergo rapid diffusional transport through cell membranes. The main advantage of large nanoparticles is higher drug encapsulation efficiency and the ability to deliver a wider array of drugs. Our present study contributes a new approach with large Tween 80 solid lipid nanoparticles SLN (i.e., hydrodynamic GM-SLN-glycerol monostearate, GM, as the lipid and ATO5-SLNs-glyceryl palmitostearate, ATO5, as the lipid) with diameters DH of 379.4 nm and 547 nm, respectively. They are used as drug carriers alone and in combination with electroporation (EP) induced by millisecond pulsed electric fields. We evaluate if EP can support the transport of large nanocarriers into cells. The study was performed with two cell lines: human colon adenocarcinoma LoVo and hamster ovarian fibroblastoid CHO-K1 with coumarin 6 (C6) as a fluorescent marker for encapsulation. The biological safety of the potential treatment procedure was evaluated with cell viability after their exposure to nanoparticles and EP. The EP efficacy was evaluated by FACS method. The impact on intracellular structure organization of cytoskeleton was visualized by CLSM method with alpha-actin and beta-tubulin. The obtained results indicate low cytotoxicity of both carrier types, free and loaded with C6. The evaluation of cytoskeleton proteins indicated no intracellular structure damage. The intracellular uptake and accumulation show that SLNs do not support transport of C6 coumarin. Only application of electroporation improved the transport of encapsulated and free C6 into both treated cell lines.

Regulatory T cells in the immunotherapy of melanoma

Patients with melanoma are supposed to develop spontaneous immune responses against specific tumor antigens. However, several mechanisms contribute to the failure of tumor antigen-specific T cell responses, inducing immune escape. Importantly, immunosuppression mediated by regulatory T cells (Tregs) in tumor lesions is a dominant mechanism of tumor immune evasion. Based on this information, several therapies targeting Tregs such as cyclophosphamide, IL-2-based therapies, and antibodies against the surface molecular of Tregs have been developed. However, only some of these strategies showed clinical efficacy in patients with melanoma in spite of their success in shifting immune systems to antitumor responses in animal models. In the future, strategies specifically depleting local Tregs, inhibiting Treg migration to the tumor lesion, and Treg depletion in combination with other chemotherapies or immune modulation will hopefully bring benefits to melanoma patients.

Electrochemotherapy of tumors as in situ vaccination boosted by immunogene electrotransfer

Electroporation is a platform technology for drug and gene delivery. When applied to cell in vitro or tissues in vivo, it leads to an increase in membrane permeability for molecules which otherwise cannot enter the cell (e.g., siRNA, plasmid DNA, and some chemotherapeutic drugs). The therapeutic effectiveness of delivered chemotherapeutics or nucleic acids depends greatly on their successful and efficient delivery to the target tissue. Therefore, the understanding of different principles of drug and gene delivery is necessary and needs to be taken into account according to the specificity of their delivery to tumors and/or normal tissues. Based on the current knowledge, electrochemotherapy (a combination of drug and electric pulses) is used for tumor treatment and has shown great potential. Its local effectiveness is up to 80 % of local tumor control, however, without noticeable effect on metastases. In an attempt to increase systemic antitumor effectiveness of electrochemotherapy, electrotransfer of genes with immunomodulatory effect (immunogene electrotransfer) could be used as adjuvant treatment. Since electrochemotherapy can induce immunogenic cell death, adjuvant immunogene electrotransfer to peritumoral tissue could lead to locoregional effect as well as the abscopal effect on distant untreated metastases. Therefore, we propose a combination of electrochemotherapy with peritumoral IL-12 electrotransfer, as a proof of principle, using electrochemotherapy boosted with immunogene electrotransfer as in situ vaccination for successful tumor treatment.

Dendritic cell cancer vaccines: from the bench to the bedside

The recognition that the development of cancer is associated with acquired immunodeficiency, mostly against cancer cells themselves, and understanding pathways inducing this immunosuppression, has led to a tremendous development of new immunological approaches, both vaccines and drugs, which overcome this inhibition. Both "passive" (e.g. strategies relying on the administration of specific T cells) and "active" vaccines (e.g. peptide-directed or whole-cell vaccines) have become attractive immunological approaches, inducing cell death by targeting tumor-associated antigens. Whereas peptide-targeted vaccines are usually directed against a single antigen, whole-cell vaccines (e.g. dendritic cell vaccines) are aimed to induce robust responsiveness by targeting several tumor-related antigens simultaneously. The combination of vaccines with new immuno-stimulating agents which target "immunosuppressive checkpoints" (anti-CTLA-4, PD-1, etc.) is likely to improve and maintain immune response induced by vaccination.