Photoactivatable oncolytic adenovirus for optogenetic cancer therapy

Optogenetic approaches for neural tissue regeneration: A review of basic optogenetic principles and target cells for therapy

Optogenetics has revolutionized the field of neuroscience by enabling precise control of neural activity through light-sensitive proteins known as opsins. This review article discusses the fundamental principles of optogenetics, including the activation of both excitatory and inhibitory opsins, as well as the development of optogenetic models that utilize recombinant viral vectors. A considerable portion of the article addresses the limitations of optogenetic tools and explores strategies to overcome these challenges. These strategies include the use of adeno-associated viruses, cell-specific promoters, modified opsins, and methodologies such as bioluminescent optogenetics. The application of viral recombinant vectors, particularly adeno-associated viruses, is emerging as a promising avenue for clinical use in delivering opsins to target cells. This trend indicates the potential for creating tools that offer greater flexibility and accuracy in opsin delivery. The adaptations of these viral vectors provide advantages in optogenetic studies by allowing for the restricted expression of opsins through cell-specific promoters and various viral serotypes. The article also examines different cellular targets for optogenetics, including neurons, astrocytes, microglia, and Schwann cells. Utilizing specific promoters for opsin expression in these cells is essential for achieving precise and efficient stimulation. Research has demonstrated that optogenetic stimulation of both neurons and glial cells-particularly the distinct phenotypes of microglia, astrocytes, and Schwann cells-can have therapeutic effects in neurological diseases. Glial cells are increasingly recognized as important targets for the treatment of these disorders. Furthermore, the article emphasizes the emerging field of bioluminescent optogenetics, which combines optogenetic principles with bioluminescent proteins to visualize and manipulate neural activity in real time. By integrating molecular genetics techniques with bioluminescence, researchers have developed methods to monitor neuronal activity efficiently and less invasively, enhancing our understanding of central nervous system function and the mechanisms of plasticity in neurological disorders beyond traditional neurobiological methods. Evidence has shown that optogenetic modulation can enhance motor axon regeneration, achieve complete sensory reinnervation, and accelerate the recovery of neuromuscular function. This approach also induces complex patterns of coordinated motor neuron activity and promotes neural reorganization. Optogenetic approaches hold immense potential for therapeutic interventions in the central nervous system. They enable precise control of neural circuits and may offer new treatments for neurological disorders, particularly spinal cord injuries, peripheral nerve injuries, and other neurodegenerative diseases.

Effect of blue light on the cell viability of A549 lung cancer cells and investigations into its possible mechanism

Blue light has attracted extensive attention as a new potential cancer therapy. Recent studies have indicated that blue light has a significant inhibition effect on A459 cells. However, the effect of light parameters on the treatment of A549 cells and the mechanism of how blue light made the effect was still unclear. This study aimed to investigate A549 cells responses to blue light with varying irradiance and dose-dense, and tried to find out the mechanism of the effects blue light made. The results suggested that the responses of A549 cells to blue light with different irradiance and dose-dense were different and the decrease of cell viability reached saturation when the irradiance reached 3 mW/cm2 and the dose-dense reached 3.6 J/cm2 . It was assumed that blue light suppressed PI3K/AKT pathway and promoted the expression of JNK and p53 to affect the proliferation of A549 cells.

Optogenetic technologies in translational cancer research

Gene and cell therapies are widely recognized as future cancer therapeutics but poor controllability limits their clinical applications. Optogenetics, the use of light-controlled proteins to precisely spatiotemporally regulate the activity of genes and cells, opens up new possibilities for cancer treatment. Light of specific wavelength can activate the immune response, oncolytic activity and modulate cell signaling in tumor cells non-invasively, in dosed manner, with tissue confined action and without side effects of conventional therapies. Here, we review optogenetic approaches in cancer research, their clinical potential and challenges of incorporating optogenetics in cancer therapy. We critically discuss beneficial combinations of optogenetic technologies with therapeutic nanobodies, T-cell activation and CAR-T cell approaches, genome editors and oncolytic viruses. We consider viral vectors and nanoparticles for delivering optogenetic payloads and activating light to tumors. Finally, we highlight herein the prospects for integrating optogenetics into immunotherapy as a novel, fast, reversible and safe approach to cancer treatment.

Viruses as tools in gene therapy, vaccine development, and cancer treatment

Using viruses to our advantage has been a huge leap for humanity. Their ability to mediate horizontal gene transfer has made them useful tools for gene therapy, vaccine development, and cancer treatment. Adenoviruses, adeno-associated viruses, retroviruses, lentiviruses, alphaviruses, and herpesviruses are a few of the most common candidates for use as therapeutic agents or efficient gene delivery systems. Efforts are being made to improve and perfect viral-vector-based therapies to overcome potential or reported drawbacks. Some preclinical trials of viral vector vaccines have yielded positive results, indicating their potential as prophylactic or therapeutic vaccine candidates. Utilization of the oncolytic activity of viruses is the future of cancer therapy, as patients will then be free from the harmful effects of chemo- or radiotherapy. This review discusses in vitro and in vivo studies showing the brilliant therapeutic potential of viruses.

The Combined Use of Orf Virus and PAK4 Inhibitor Exerts Anti-tumor Effect in Breast Cancer

The parapoxvirus Orf virus (ORFV) has long been recognized as one of the valuable vectors in researches of oncolytic virus. In order to develop a potential therapeutic strategy for breast cancer based on the oncolytic virotherapy via ORFV, firstly we explore the oncolytic effects of ORFV. Our research showed that ORFV exerts anti-tumor effects in vitro by inducing breast cancer cell G2/M phase arrest and cell apoptosis. In vivo experiments were carried out, in which we treated 4T1 tumor-bearing BALB/C mice via intratumoral injection of ORFV. ORFV can exert anti-tumor activity by regulating tumor microenvironment (TME) and inducing a host immune response plus directly oncolytic effect. The CRISPR-Cas9 knockout library targeting 507 kinases was used to screen out PAK4, which is beneficial to the anti-tumor effect of ORFV on breast cancer cells. PF-3758309 is a potent PAK4-targeted inhibitor. Co-using of ORFV and PF-3758309 as a combination treatment produces its anti-tumor effects through inhibition of cell viability, induction of apoptosis and suppression of cell migration and invasion in vitro. The results of in vivo experiments showed that the tumor growth of mice in the combination treatment group was significantly inhibited, which proved that the combination treatment exerts an effective anti-tumor effect in vivo. In summary, we have clarified the oncolytic effect of ORFV on breast cancer, and found that the combination of ORFV and PAK4 inhibitor can effectively improve the oncolytic effect of ORFV. We hope our research could provide a new idea for the development of new treatment strategies for breast cancer.

Femtosecond-laser stimulation induces senescence of tumor cells in vitro and in vivo

Tumor cells present anti-apoptosis and abnormal proliferation during development. Senescence and stemness of tumor cells play key roles in tumor development and malignancy. In this study, we show the transient stimulation by a single-time scanning of tightly focused femtosecond laser to tumor cells can modulate the stemness and senescence in vitro and in vivo. The laser-induced cellular senescence and stemness present distinct transitions in vitro and in vivo. The cells 1.2 mm deep in tumor tissue are found with significant senescence induced by the transient photostimulations in 100-200 µm shallow layer in vivo, which suppresses the growth of whole tumor in living mice.

The Disassociation of the A20/HSP90 Complex via Downregulation of HSP90 Restores the Effect of A20 Enhancing the Sensitivity of Hepatocellular Carcinoma Cells to Molecular Targeted Agents

NF-κB (nuclear factor κB) is a regulator of hepatocellular cancer (HCC)-related inflammation and enhances HCC cells' resistance to antitumor therapies by promoting cell survival and anti-apoptosis processes. In the present work, we demonstrate that A20, a dominant-negative regulator of NF-κB, forms a complex with HSP90 (heat-shock protein 90) and causes the disassociation of the A20/HSP90 complex via downregulation of HSP90. This process restores the antitumor activation of A20. In clinical specimens, the expression level of A20 did not relate with the outcome in patients receiving sorafenib; however, high levels of HSP90 were associated with poor outcomes in these patients. A20 interacted with and formed complexes with HSP90. Knockdown of HSP90 and treatment with an HSP90 inhibitor disassociated the A20/HSP90 complex. Overexpression of A20 alone did not affect HCC cells. Downregulation of HSP90 combined with A20 overexpression restored the effect of A20. Overexpression of A20 repressed the expression of pro-survival and anti-apoptosis-related factors and enhanced HCC cells' sensitivity to sorafenib. These results suggest that interactions with HSP90 could be potential mechanisms of A20 inactivation and disassociation of the A20/HSP90 complex and could serve as a novel strategy for HCC treatment.

Spatiotemporally confined red light-controlled gene delivery at single-cell resolution using adeno-associated viral vectors

Methodologies for the controlled delivery of genetic information into target cells are of utmost importance for genetic engineering in both fundamental and applied research. However, available methods for efficient gene transfer into user-selected or even single cells suffer from low throughput, the need for complicated equipment, high invasiveness, or side effects by off-target viral uptake. Here, we engineer an adeno-associated viral (AAV) vector system that transfers genetic information into native target cells upon illumination with cell-compatible red light. This OptoAAV system allows adjustable and spatially resolved gene transfer down to single-cell resolution and is compatible with different cell lines and primary cells. Moreover, the sequential application of multiple OptoAAVs enables spatially resolved transduction with different transgenes. The approach presented is likely extendable to other classes of viral vectors and is expected to foster advances in basic and applied genetic research.

Optogenetic Approaches for the Spatiotemporal Control of Signal Transduction Pathways

Biological signals are sensed by their respective receptors and are transduced and processed by a sophisticated intracellular signaling network leading to a signal-specific cellular response. Thereby, the response to the signal depends on the strength, the frequency, and the duration of the stimulus as well as on the subcellular signal progression. Optogenetic tools are based on genetically encoded light-sensing proteins facilitating the precise spatiotemporal control of signal transduction pathways and cell fate decisions in the absence of natural ligands. In this review, we provide an overview of optogenetic approaches connecting light-regulated protein-protein interaction or caging/uncaging events with steering the function of signaling proteins. We briefly discuss the most common optogenetic switches and their mode of action. The main part deals with the engineering and application of optogenetic tools for the control of transmembrane receptors including receptor tyrosine kinases, the T cell receptor and integrins, and their effector proteins. We also address the hallmarks of optogenetics, the spatial and temporal control of signaling events.

Oncolytic Virotherapy in Solid Tumors: The Challenges and Achievements

Oncolytic virotherapy (OVT) is a promising approach in cancer immunotherapy. Oncolytic viruses (OVs) could be applied in cancer immunotherapy without in-depth knowledge of tumor antigens. The capability of genetic modification makes OVs exciting therapeutic tools with a high potential for manipulation. Improving efficacy, employing immunostimulatory elements, changing the immunosuppressive tumor microenvironment (TME) to inflammatory TME, optimizing their delivery system, and increasing the safety are the main areas of OVs manipulations. Recently, the reciprocal interaction of OVs and TME has become a hot topic for investigators to enhance the efficacy of OVT with less off-target adverse events. Current investigations suggest that the main application of OVT is to provoke the antitumor immune response in the TME, which synergize the effects of other immunotherapies such as immune-checkpoint blockers and adoptive cell therapy. In this review, we focused on the effects of OVs on the TME and antitumor immune responses. Furthermore, OVT challenges, including its moderate efficiency, safety concerns, and delivery strategies, along with recent achievements to overcome challenges, are thoroughly discussed.

A Tumor-Targeted Replicating Oncolytic Adenovirus Ad-TD-nsIL12 as a Promising Therapeutic Agent for Human Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most lethal cancers in China and existing therapies have been unable to significantly improve prognosis. Oncolytic adenoviruses (OAds) are novel promising anti-tumor drugs and have been evaluated in several cancers including ESCC. However, the antitumour efficacy of the first generation OAds (H101) as single agent is limited. Therefore, more effective OAds are needed. Our previous studies demonstrated that the novel oncolytic adenovirus Ad-TD-nsIL12 (human adenovirus type 5 with E1ACR2, E1B19K, E3gp19K-triple deletions)harboring human non-secretory IL-12 had significant anti-tumor effect, with no toxicity, in a Syrian hamster pancreatic cancer model. In this study, we evaluated the anti-tumor effect of Ad-TD-nsIL12 in human ESCC. The cytotoxicity of Ad-TD-nsIL12, H101 and cisplatin were investigated in two newly established patient-derived tumor cells (PDCs) and a panel of ESCC cell lines in vitro. A novel adenovirus-permissive, immune-deficient Syrian hamster model of PDCs subcutaneous xenograft was established for in vivo analysis of efficacy. The results showed that Ad-TD-nsIL12 was more cytotixic to and replicated more effectively in human ESCC cell lines than H101. Compared with cisplatin and H101, Ad-TD-nsIL12 could significantly inhibit tumor growth and tumor angiogenesis as well as enhance survival rate of animals with no side effects. These findings suggest that Ad-TD-nsIL12 has superior anti-tumor potency against human ESCC with a good safety profile.