An Optogenetic Controllable T Cell System for Hepatocellular Carcinoma Immunotherapy

Ultrasound-mediated spatial and temporal control of engineered cells in vivo

Remote regulation of cells in deep tissue remains a significant challenge. Low-intensity pulsed ultrasound offers promise for in vivo therapies due to its non-invasive nature and precise control. This study uses pulsed ultrasound to control calcium influx in mammalian cells and engineers a therapeutic cellular device responsive to acoustic stimulation in deep tissue without overexpressing calcium channels or gas vesicles. Pulsed ultrasound parameters are established to induce calcium influx in HEK293 cells. Additionally, cells are engineered to express a designed calcium-responsive transcription factor controlling the expression of a selected therapeutic gene, constituting a therapeutic cellular device. The engineered sonogenetic system's functionality is demonstrated in vivo in mice, where an implanted anti-inflammatory cytokine-producing cellular device effectively alleviates acute colitis, as shown by improved colonic morphology and histopathology. This approach provides a powerful tool for precise, localized control of engineered cells in deep tissue, showcasing its potential for targeted therapeutic delivery.

Reshaping tumor microenvironment by regulating local cytokines expression with a portable smart blue-light controlled device

Cytokines have attracted sustained attention due to their multi-functional cellular response in immunotherapy. However, their application was limited to their short half-time, narrow therapeutic window, and undesired side effects. To address this issue, we developed a portable smart blue-light controlled (PSLC) device based on optogenetic technology. By combining this PSLC device with blue-light controlled gene modules, we successfully achieved the targeted regulation of cytokine expression within the tumor microenvironment. To alter the tumor microenvironment of solid tumors, pro-inflammatory cytokines were selected as blue-light controlled molecules. The results show that blue-light effectively regulates the expression of pro-inflammatory cytokines both in vitro and in vivo. This strategy leads to enhanced and activated tumor-infiltrating immune cells, which facilitated to overcome the immunosuppressive microenvironment, resulting in significant tumor shrinkage in tumor-bearing mice. Hence, our study offers a unique strategy for cytokine therapy and a convenient device for animal studies in optogenetic immunotherapy.

Development of an optogenetics tool, Opto-RANK, for control of osteoclast differentiation using blue light

Optogenetics enables precise regulation of intracellular signaling in target cells. However, the application of optogenetics to induce the differentiation of precursor cells and generate mature cells with specific functions has not yet been fully explored. Here, we focused on osteoclasts, which play an important role in bone remodeling, to develop a novel optogenetics tool, Opto-RANK, which can manipulate intracellular signals involved in osteoclast differentiation and maturation using blue light. We engineered Opto-RANK variants, Opto-RANKc and Opto-RANKm, and generated stable cell lines through retroviral transduction. Differentiation was induced by blue light, and various assays were conducted for functional analysis. Osteoclast precursor cells expressing Opto-RANK differentiated into multinucleated giant cells on light exposure and displayed upregulation of genes normally induced in differentiated osteoclasts. Furthermore, the differentiated cells exhibited bone-resorbing activities, with the possibility of spatial control of the resorption by targeted light illumination. These results suggested that Opto-RANK cells differentiated by light possess the features of osteoclasts, both morphological and functional. Thus, Opto-RANK should be useful for detailed spatiotemporal analysis of intracellular signaling during osteoclast differentiation and the development of new therapies for various bone diseases.

Optical sensing and control of T cell signaling pathways

T cells regulate adaptive immune responses through complex signaling pathways mediated by T cell receptor (TCR). The functional domains of the TCR are combined with specific antibodies for the development of chimeric antigen receptor (CAR) T cell therapy. In this review, we first overview current understanding on the T cell signaling pathways as well as traditional methods that have been widely used for the T cell study. These methods, however, are still limited to investigating dynamic molecular events with spatiotemporal resolutions. Therefore, genetically encoded biosensors and optogenetic tools have been developed to study dynamic T cell signaling pathways in live cells. We review these cutting-edge technologies that revealed dynamic and complex molecular mechanisms at each stage of T cell signaling pathways. They have been primarily applied to the study of dynamic molecular events in TCR signaling, and they will further aid in understanding the mechanisms of CAR activation and function. Therefore, genetically encoded biosensors and optogenetic tools offer powerful tools for enhancing our understanding of signaling mechanisms in T cells and CAR-T cells.

Emerging optogenetics technologies in biomedical applications

Optogenetics is a cutting-edge technology that merges light control and genetics to achieve targeted control of tissue cells. Compared to traditional methods, optogenetics offers several advantages in terms of time and space precision, accuracy, and reduced damage to the research object. Currently, optogenetics is primarily used in pathway research, drug screening, gene expression regulation, and the stimulation of molecule release to treat various diseases. The selection of light-sensitive proteins is the most crucial aspect of optogenetic technology; structural changes occur or downstream channels are activated to achieve signal transmission or factor release, allowing efficient and controllable disease treatment. In this review, we examine the extensive research conducted in the field of biomedicine concerning optogenetics, including the selection of light-sensitive proteins, the study of carriers and delivery devices, and the application of disease treatment. Additionally, we offer critical insights and future implications of optogenetics in the realm of clinical medicine.

Light-inducible T cell engagers trigger, tune, and shape the activation of primary T cells

To mount appropriate responses, T cells integrate complex sequences of receptor stimuli perceived during transient interactions with antigen-presenting cells. Although it has been hypothesized that the dynamics of these interactions influence the outcome of T cell activation, methodological limitations have hindered its formal demonstration. Here, we have engineered the Light-inducible T cell engager (LiTE) system, a recombinant optogenetics-based molecular tool targeting the T cell receptor (TCR). The LiTE system constitutes a reversible molecular switch displaying exquisite reactivity. As proof of concept, we dissect how specific temporal patterns of TCR stimulation shape T cell activation. We established that CD4+ T cells respond to intermittent TCR stimulation more efficiently than their CD8+ T cells counterparts and provide evidence that distinct sequences of TCR stimulation encode different cytokine programs. Finally, we show that the LiTE system could be exploited to create light-activated bispecific T cell engagers and manipulate tumor cell killing. Overall, the LiTE system provides opportunities to understand how T cells integrate TCR stimulations and to trigger T cell cytotoxicity with high spatiotemporal control.

Synthesizing a Smarter CAR T Cell: Advanced Engineering of T-cell Immunotherapies

The immune system includes an array of specialized cells that keep us healthy by responding to pathogenic cues. Investigations into the mechanisms behind immune cell behavior have led to the development of powerful immunotherapies, including chimeric-antigen receptor (CAR) T cells. Although CAR T cells have demonstrated efficacy in treating blood cancers, issues regarding their safety and potency have hindered the use of immunotherapies in a wider spectrum of diseases. Efforts to integrate developments in synthetic biology into immunotherapy have led to several advancements with the potential to expand the range of treatable diseases, fine-tune the desired immune response, and improve therapeutic cell potency. Here, we examine current synthetic biology advances that aim to improve on existing technologies and discuss the promise of the next generation of engineered immune cell therapies.

Emerging Trends in Nano-Driven Immunotherapy for Treatment of Cancer

Despite advancements in the development of anticancer medications and therapies, cancer still has the greatest fatality rate due to a dismal prognosis. Traditional cancer therapies include chemotherapy, radiotherapy, and targeted therapy. The conventional treatments have a number of shortcomings, such as a lack of selectivity, non-specific cytotoxicity, suboptimal drug delivery to tumour locations, and multi-drug resistance, which results in a less potent/ineffective therapeutic outcome. Cancer immunotherapy is an emerging and promising strategy to elicit a pronounced immune response against cancer. Immunotherapy stimulates the immune system with cancer-specific antigens or immune checkpoint inhibitors to overcome the immune suppressive tumour microenvironment and kill the cancer cells. However, delivery of the antigen or immune checkpoint inhibitors and activation of the immune response need to circumvent the issues pertaining to short lifetimes and effect times, as well as adverse effects associated with off-targeting, suboptimal, or hyperactivation of the immune system. Additional challenges posed by the tumour suppressive microenvironment are less tumour immunogenicity and the inhibition of effector T cells. The evolution of nanotechnology in recent years has paved the way for improving treatment efficacy by facilitating site-specific and sustained delivery of the therapeutic moiety to elicit a robust immune response. The amenability of nanoparticles towards surface functionalization and tuneable physicochemical properties, size, shape, and surfaces charge have been successfully harnessed for immunotherapy, as well as combination therapy, against cancer. In this review, we have summarized the recent advancements made in choosing different nanomaterial combinations and their modifications made to enable their interaction with different molecular and cellular targets for efficient immunotherapy. This review also highlights recent trends in immunotherapy strategies to be used independently, as well as in combination, for the destruction of cancer cells, as well as prevent metastasis and recurrence.

Recent progress of gene circuit designs in immune cell therapies

The success of chimeric antigen receptor (CAR) T cell therapy against hematological cancers has convincingly demonstrated the potential of using genetically engineered cells as therapeutic agents. Although much progress has been achieved in cell therapy, more beneficial capabilities have yet to be fully explored. One of the unique advantages afforded by cell therapies is the possibility to implement genetic control circuits, which enables diverse signal sensing and logical processing for optimal response in the complex tumor microenvironment. In this perspective, we will first outline design considerations for cell therapy control circuits that address clinical demands. We will compare and contrast key design features in some of the latest control circuits developments and conclude by discussing potential future directions.

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.

Engineering of optogenetic devices for biomedical applications in mammalian synthetic biology

Gene- and cell-based therapies are the next frontiers in the field of medicine. Both are transformative and innovative therapies; however, a lack of safety data limits the translation of such promising technologies to the clinic. Improving the safety and promoting the clinical translation of these therapies can be achieved by tightly regulating the release and delivery of therapeutic outputs. In recent years, the rapid development of optogenetic technology has provided opportunities to develop precision-controlled gene- and cell-based therapies, in which light is introduced to precisely and spatiotemporally manipulate the behaviour of genes and cells. This review focuses on the development of optogenetic tools and their applications in biomedicine, including photoactivated genome engineering and phototherapy for diabetes and tumours. The prospects and challenges of optogenetic tools for future clinical applications are also discussed.

Special Chimeric Antigen Receptor (CAR) Modifications of T Cells: A Review

Chimeric antigen receptor (CAR) -T cell therapy has become one of the hot topics in tumor immunity research in recent years. Although CAR-T cell therapy is highly effective in treating hematological malignancies, there are numerous obstacles that prevent CAR-T cells from having anti-tumor effects. Traditional CARs, from the first to the fourth generation, are incapable of completely overcoming these challenges. Therefore, identifying ways to boost the efficacy of CAR-T cells by utilizing the limited tumor surface antigens has become an urgent area of research. Certain special CARs that have special structures, special systems, or are greatly improved on the basis of traditional CARs, such as tandem CAR, dual-signaling CARs, AND-gate CARs, inhibitory CAR, AND-NOT CARs, CARs with three scFvs, ON/OFF-switch CARs, and universal CARs have been introduced. This study aims to use these special CARs to improve the anti-tumor ability, accuracy, and safety of CAR-T cells. In addition to summarizing various special CARs of T cells, this paper also expounds some of our own conjectures, aiming to provide reference and inspiration for CARs researchers.

Far-Red Light Triggered Production of Bispecific T Cell Engagers (BiTEs) from Engineered Cells for Antitumor Application

Bispecific T-cell engagers (BiTEs), which have shown potent antitumor activity in humans, are emerging as one of the most promising immunotherapeutic strategies for cancer treatment in recent years. However, the clinical application of BiTEs nowadays has been hampered by their short half-life in the circulatory system due to their low molecular weight and rapid renal clearance. Inevitable continuous infusion of BiTEs has become a routine operation in order to achieve effective treatment, although it is costly, inconvenient, time-consuming, and even painful for patients in some cases. To develop an on-demand, tunable, and reversible approach to overcome these limitations, we assembled a transcription-control device into mammalian cells based on a bacterial far-red light (FRL) responsive signaling pathway to drive the expression of a BiTE against Glypican 3 (GPC3), which is a highly tumor-specific antigen expressed in most hepatocellular carcinomas (HCC). As demonstrated in in vitro experiments, we proved that the FRL sensitive device spatiotemporally responded to the control of FRL illumination and produced a therapeutic level of BiTEs that recruited and activated human T cells to eliminate GPC3 positive tumor cells. By functionally harnessing the power of optogenetics to remotely regulate the production of BiTEs from bioengineered cells and demonstrating its effectiveness in treating tumor cells, this study provides a novel approach to achieve an in vivo supply of BiTEs, which could be potentially applied to other formats of bispecific antibodies and facilitate their clinical applications.

Construction of Durvalumab/carbon nanotube/PEI/aptamer-siRNA chimera for the immunotherapy of hepatocellular carcinoma

Immunotherapy is the most promising treatment for hepatocellular carcinoma (HCC). However, the immunosuppressive microenvironment and necrosis limit its therapeutic effectiveness. Carbon nanotubes (CNTs) have good tissue permeability and can penetrate tumor necrosis area. Here we constructed a Durvalumab/CNT/PEI/ aptamer-siRNA chimera (chimera/Durmab/CNT) nanoparticles for the immunotherapy of HCC. In vivo and in vitro experiments showed that aptamer-siRNA chimeras could specifically bind HCC cells and inhibit the triggering receptor expressed on myeloid cells-2 (Trem2) expression, but had no effect on Trem2 expression in normal liver and lung. Transmission electron microscope (TEM) results showed that the CNT/PEI nanoparticles were 20-30 nm in diameter and 200-350nm in length. Dense PEI attachment can be observed on CNTs. CNT/PEI nanoparticles could control the sustained release of Durvalumab for 48 hours. In vitro experimental results showed that chimera/Durmab/CNT could increase the proportion of T cells and CD8+T cells, and then promote the apoptosis of HepG2 cells, and the therapeutic effect was superior to aptamer/Durmab/CNT and Durmab/CNT. We constructed a tumor-bearing mouse model, and the results showed that chimera/Durmab/CNT significantly inhibited the growth of transplanted tumor, and the volume and proliferation was further reduced in the chimera/Durmab/CNT group compared with the aptamer/Durmab/CNT group. T cells and CD8+T cells infiltration, and HCC cell apoptosis were significantly increased in the chimera/Durmab/CNT group. In conclusion, we constructed a Durvalumab/CNT/PEI/chimera, which can effectively treat HCC by activating anti-tumor immunity.

Optophysiology: Illuminating cell physiology with optogenetics

Optogenetics combines light and genetics to enable precise control of living cells, tissues, and organisms with tailored functions. Optogenetics has the advantages of noninvasiveness, rapid responsiveness, tunable reversibility, and superior spatiotemporal resolution. Following the initial discovery of microbial opsins as light-actuated ion channels, a plethora of naturally occurring or engineered photoreceptors or photosensitive domains that respond to light at varying wavelengths has ushered in the next chapter of optogenetics. Through protein engineering and synthetic biology approaches, genetically-encoded photoswitches can be modularly engineered into protein scaffolds or host cells to control a myriad of biological processes, as well as to enable behavioral control and disease intervention in vivo. Here, we summarize these optogenetic tools on the basis of their fundamental photochemical properties to better inform the chemical basis and design principles. We also highlight exemplary applications of opsin-free optogenetics in dissecting cellular physiology (designated "optophysiology"), and describe the current progress, as well as future trends, in wireless optogenetics, which enables remote interrogation of physiological processes with minimal invasiveness. This review is anticipated to spark novel thoughts on engineering next-generation optogenetic tools and devices that promise to accelerate both basic and translational studies.

Far-red light-activated human islet-like designer cells enable sustained fine-tuned secretion of insulin for glucose control

Diabetes affects almost half a billion people, and all individuals with type 1 diabetes (T1D) and a large portion of individuals with type 2 diabetes rely on self-administration of the peptide hormone insulin to achieve glucose control. However, this treatment modality has cumbersome storage and equipment requirements and is susceptible to fatal user error. Here, reasoning that a cell-based therapy could be coupled to an external induction circuit for blood glucose control, as a proof of concept we developed far-red light (FRL)-activated human islet-like designer (FAID) cells and demonstrated how FAID cell implants achieved safe and sustained glucose control in diabetic model mice. Specifically, by introducing a FRL-triggered optogenetic device into human mesenchymal stem cells (hMSCs), which we encapsulated in poly-(l-lysine)-alginate and implanted subcutaneously under the dorsum of T1D model mice, we achieved FRL illumination-inducible secretion of insulin that yielded improvements in glucose tolerance and sustained blood glucose control over traditional insulin glargine treatment. Moreover, the FAID cell implants attenuated both oxidative stress and development of multiple diabetes-related complications in kidneys. This optogenetics-controlled "living cell factory" platform could be harnessed to develop multiple synthetic designer therapeutic cells to achieve long-term yet precisely controllable drug delivery.

The state of the art of biomedical applications of optogenetics

BACKGROUND AND OBJECTIVE

Optogenetics has opened new insights into biomedical research with the ability to manipulate and control cellular activity using light in combination with genetically engineered photosensitive proteins. By stimulating with light, this method provides high spatiotemporal and high specificity resolution, which is in contrast to conventional pharmacological or electrical stimulation. Optogenetics was initially introduced to control neural activities but was gradually extended to other biomedical fields.

STUDY DESIGN

In this paper, firstly, we summarize the current optogenetic tools stimulated by different light sources, including lasers, light-emitting diodes, and laser diodes. Second, we outline the variety of biomedical applications of optogenetics not only for neuronal circuits but also for various kinds of cells and tissues from cardiomyocytes to ganglion cells. Furthermore, we highlight the potential of this technique for treating neurological disorders, cardiac arrhythmia, visual impairment, hearing loss, and urinary bladder diseases as well as clarify the mechanisms underlying cancer progression and control of stem cell differentiation.

CONCLUSION

We sought to summarize the various types of promising applications of optogenetics to treat a broad spectrum of disorders. It is conceivable to expect that optogenetics profits a growing number of patients suffering from a range of different diseases in the near future.

Emerging mammalian gene switches for controlling implantable cell therapies

Engineered cell-based therapies have emerged as a new paradigm in modern medicine, with several engineered T cell therapies currently approved to treat blood cancers and many more in clinical development. Tremendous progress in synthetic biology over the past two decades has allowed us to program cells with sophisticated sense-and-response modules that can effectively control therapeutic functions. In this review, we highlight recent advances in mammalian synthetic gene switches, focusing on devices designed for therapeutic applications. Although many gene switches responding to endogenous or exogenous molecular signals have been developed, the focus is shifting towards achieving remote-controlled production of therapeutic effectors by stimulating implanted engineered cells with traceless physical signals, such as light, electrical signals, magnetic fields, heat or ultrasound.

Engineering Supramolecular Organizing Centers for Optogenetic Control of Innate Immune Responses

The spatiotemporal organization of oligomeric protein complexes, such as the supramolecular organizing centers (SMOCs) made of MyDDosome and MAVSome, is essential for transcriptional activation of host inflammatory responses and immunometabolism. Light-inducible assembly of MyDDosome and MAVSome is presented herein to induce activation of nuclear factor-kB and type-I interferons. Engineering of SMOCs and the downstream transcription factor permits programmable and customized innate immune operations in a light-dependent manner. These synthetic molecular tools will likely enable optical and user-defined modulation of innate immunity at a high spatiotemporal resolution to facilitate mechanistic studies of distinct modes of innate immune activations and potential intervention of immune disorders and cancer.

A remotely controlled NIR-II photothermal-sensitive transgene system for hepatocellular carcinoma synergistic therapy

Photothermal therapy (PTT) exhibits an excellent therapeutic effect in cancer treatment, but some cancers are still facing rapid recurrence due to the presence of heat-resistant cells, which express heat shock proteins (HSP) to defend against hyperthermia. Inspired by optogenetics, we firstly designed a caged TNF-related apoptosis-inducing ligand (TRAIL) expressing plasmid under HSP70 protomer (HSP70-TRAIL) as the thermal-activated gene therapy agent to induce the apoptosis of heat resistant cells. Then, the caged HSP70-TRAIL was decorated on the surface of the photothermal agent (semiconducting nanoparticles, SPNs) through electrostatic adsorption to obtain SPN@HSP70-TRAIL-GFP (SPNHT). Under 1064 nm near-infrared second region (NIR-II) laser irradiation, the SPNHT acted as an emerging photothermal agent for PTT. Importantly, the caged HSP70-TRAIL could be further activated by PTT to express TRAIL on demand to concurrently kill survival cells for overcoming the problem of tumor recurrence after PTT. Both in vitro and in vivo studies demonstrated that the SPNHT nano-system with the ability of NIR-II photothermal-triggered TRAIL in situ expression possessed an admirable synergistic anti-cancer efficacy for HCC. This work offers new tactics for effective treatment of cancer, which showed a great significance for reducing the rate of cancer recurrence after PTT treatment.

Precision Tools in Immuno-Oncology: Synthetic Gene Circuits for Cancer Immunotherapy

Engineered mammalian cells for medical purposes are becoming a clinically relevant reality thanks to advances in synthetic biology that allow enhanced reliability and safety of cell-based therapies. However, their application is still hampered by challenges including time-consuming design-and-test cycle iterations and costs. For example, in the field of cancer immunotherapy, CAR-T cells targeting CD19 have already been clinically approved to treat several types of leukemia, but their use in the context of solid tumors is still quite inefficient, with additional issues related to the adequate quality control for clinical use. These limitations can be overtaken by innovative bioengineering approaches currently in development. Here we present an overview of recent synthetic biology strategies for mammalian cell therapies, with a special focus on the genetic engineering improvements on CAR-T cells, discussing scenarios for the next generation of genetic circuits for cancer immunotherapy.

Exploiting Ca2+ signaling in T cells to advance cancer immunotherapy

Decades of basic research has established the importance of Ca²⁺ to various T cell functions, such as cytotoxicity, proliferation, differentiation and cytokine secretion. We now have a good understanding of how proximal TCR signaling initiates Ca²⁺ influx and how this influx subsequently changes transcriptional activities in T cells. As chimeric antigen receptor (CAR)-T therapy has achieved great clinical success, is it possible to harness Ca²⁺ signaling to further advance CAR-T research? How is CAR signaling different from TCR signaling? How can functional CARs be identified in a high-throughput way? Quantification of various Ca²⁺ signals downstream of CAR/TCR activation might help answer these questions. Here we first summarized recent studies that used Ca²⁺ dye, genetically-encoded Ca²⁺ indicators (GECI) or transcriptional activity reporters to understand CAR activation in vitro and in vivo. We next reviewed several proof-of-concept reports that manipulate Ca²⁺ signaling by light or ultrasound to achieve precise spatiotemporal control of T cell functions. These efforts, though preliminary, opened up new avenues to solve the on-target/off-tumor problem of therapeutic T cells. Other modalities to regulate Ca²⁺ signaling, such as radio wave and electrical pulse, were also discussed. Thus, monitoring or manipulating Ca²⁺ signaling in T cells provides us many opportunities to advance cancer immunotherapy.

Externally-Controlled Systems for Immunotherapy: From Bench to Bedside

Immunotherapy is a very promising therapeutic approach against cancer that is particularly effective when combined with gene therapy. Immuno-gene therapy approaches have led to the approval of four advanced therapy medicinal products (ATMPs) for the treatment of p53-deficient tumors (Gendicine and Imlygic), refractory acute lymphoblastic leukemia (Kymriah) and large B-cell lymphomas (Yescarta). In spite of these remarkable successes, immunotherapy is still associated with severe side effects for CD19+ malignancies and is inefficient for solid tumors. Controlling transgene expression through an externally administered inductor is envisioned as a potent strategy to improve safety and efficacy of immunotherapy. The aim is to develop smart immunogene therapy-based-ATMPs, which can be controlled by the addition of innocuous drugs or agents, allowing the clinicians to manage the intensity and durability of the therapy. In the present manuscript, we will review the different inducible, versatile and externally controlled gene delivery systems that have been developed and their applications to the field of immunotherapy. We will highlight the advantages and disadvantages of each system and their potential applications in clinics.

Overhauling CAR T Cells to Improve Efficacy, Safety and Cost

Gene therapy is now surpassing 30 years of clinical experience and in that time a variety of approaches has been applied for the treatment of a wide range of pathologies. While the promise of gene therapy was over-stated in the 1990’s, the following decades were met with polar extremes between demonstrable success and devastating setbacks. Currently, the field of gene therapy is enjoying the rewards of overcoming the hurdles that come with turning new ideas into safe and reliable treatments, including for cancer. Among these modalities, the modification of T cells with chimeric antigen receptors (CAR-T cells) has met with clear success and holds great promise for the future treatment of cancer. We detail a series of considerations for the improvement of the CAR-T cell approach, including the design of the CAR, routes of gene transfer, introduction of CARs in natural killer and other cell types, combining the CAR approach with checkpoint blockade or oncolytic viruses, improving pre-clinical models as well as means for reducing cost and, thus, making this technology more widely available. While CAR-T cells serve as a prime example of translating novel ideas into effective treatments, certainly the lessons learned will serve to accelerate the current and future development of gene therapy drugs.

Optogenetic approaches to control Ca2+-modulated physiological processes

As a versatile intracellular second messenger, calcium ion (Ca²⁺) regulates a plethora of physiological processes. To achieve precise control over Ca²⁺ signals in living cells and organisms, a set of optogenetic tools have recently been crafted by engineering photosensitive domains into intracellular signaling proteins, G-protein coupled receptors (GPCRs), receptor tyrosine kinases (RTKs), and Ca²⁺ channels. We highlight herein the optogenetic engineering strategies, kinetic properties, advantages and limitations of these genetically-encoded Ca²⁺ channel actuators (GECAs) and modulators. In parallel, we present exemplary applications in both excitable and non-excitable cells and tissues. Furthermore, we briefly discuss potential solutions for wireless optogenetics to accelerate the in vivo applications of GECAs under physiological conditions, with an emphasis on integrating near-infrared (NIR) light-excitable upconversion nanoparticles (UCNPs) and bioluminescence with optogenetics.

Optogenetic manipulation of calcium signals in single T cells in vivo

By offering the possibility to manipulate cellular functions with spatiotemporal control, optogenetics represents an attractive tool for dissecting immune responses. However, applying these approaches to single cells in vivo remains particularly challenging for immune cells that are typically located in scattering tissues. Here, we introduce an improved calcium actuator with sensitivity allowing for two-photon photoactivation. Furthermore, we identify an actuator/reporter combination that permits the simultaneous manipulation and visualization of calcium signals in individual T cells in vivo. With this strategy, we document the consequences of defined patterns of calcium signals on T cell migration, adhesion, and chemokine release. Manipulation of individual immune cells in vivo should open new avenues for establishing the functional contribution of single immune cells engaged in complex reactions.

The ability to manipulate and monitor calcium signaling in cells in vivo would provide insights into signaling in an endogenous context. Here the authors develop a two-photon-responsive calcium actuator and reporter combination to monitor the effect of calcium actuation on T cell migration, adhesion and chemokine release in vivo.

Synthetic immunity by remote control

Cell-based immunotherapies, such as T cells engineered with chimeric antigen receptors (CARs), have the potential to cure patients of disease otherwise refractory to conventional treatments. Early-on-treatment and long-term durability of patient responses depend critically on the ability to control the potency of adoptively transferred T cells, as overactivation can lead to complications like cytokine release syndrome, and immunosuppression can result in ineffective responses to therapy. Drugs or biologics (e.g., cytokines) that modulate immune activity are limited by mass transport barriers that reduce the local effective drug concentration, and lack site or target cell specificity that results in toxicity. Emerging technologies that enable site-targeted, remote control of key T cell functions - including proliferation, antigen-sensing, and target-cell killing - have the potential to increase treatment precision and safety profile. These technologies are broadly applicable to other immune cells to expand immune cell therapies across many cancers and diseases. In this review, we highlight the opportunities, challenges and the current state-of-the-art for remote control of synthetic immunity.

Loss of histone macroH2A1 in hepatocellular carcinoma cells promotes paracrine-mediated chemoresistance and CD4+CD25+FoxP3+ regulatory T cells activation

Rationale: Loss of histone macroH2A1 induces appearance of cancer stem cells (CSCs)-like cells in hepatocellular carcinoma (HCC). How CSCs interact with the tumor microenvironment and the adaptive immune system is unclear. Methods: We screened aggressive human HCC for macroH2A1 and CD44 CSC marker expression. We also knocked down (KD) macroH2A1 in HCC cells, and performed integrated transcriptomic and secretomic analyses. Results: Human HCC showed low macroH2A1 and high CD44 expression compared to control tissues. MacroH2A1 KD CSC-like cells transferred paracrinally their chemoresistant properties to parental HCC cells. MacroH2A1 KD conditioned media transcriptionally reprogrammed parental HCC cells activated regulatory CD4⁺/CD25⁺/FoxP3⁺ T cells (Tregs). Conclusions: Loss of macroH2A1 in HCC cells drives cancer stem-cell propagation and evasion from immune surveillance.

Construction of a Multiwell Light-Induction Platform for Traceless Control of Gene Expression in Mammalian Cells

Mammalian cells can be engineered to incorporate light-responsive elements that reliably sense stimulation by light and activate endogenous pathways, such as the cAMP or Ca²⁺ pathway, to control gene expression. Light-inducible gene expression systems offer high spatiotemporal resolution, and are also traceless, reversible, tunable, and inexpensive. Melanopsin, a well-known representative of the animal opsins, is a G-protein-coupled receptor that triggers a Gαq-dependent signaling cascade upon activation with blue light (≈470 nm). Here, we describe how to rewire melanopsin activation by blue light to transgene expression in mammalian cells, with detailed instructions for constructing a 96-LED array platform with multiple tunable parameters for illumination of the engineered cells in multiwell plates.

Optogenetic control of mesenchymal cell fate towards precise bone regeneration

Rationale: Spatial-temporal control of cell fate in vivo is of great importance for regenerative medicine. Currently, there remain no practical strategies to tune cell-fate spatial-temporally. Optogenetics is a biological technique that widely used to control cell activity in genetically defined neurons in a spatiotemporal-specific manner by light. In this study, optogenetics was repurposed for precise bone tissue regeneration.

Methods: Lhx8 and BMP2 genes, which are considered as the master genes for mesenchymal stem cell proliferation and differentiation respectively, were recombined into a customized optogenetic control system. In the system, Lhx8 was constitutively expressed, while BMP2 together with shLhx8 expression was driven by blue light.

Results: As expected, blue light induced BMP2 expression and inactivated Lhx8 expression in cells infected with the optogenetic control system. Optogenetic control of BMP2 and Lhx8 expression inversely regulates MSC fate in vitro. By animal study, we found that blue light could fine-tune the regeneration in vivo. Blue light illumination significantly promotes bone regeneration when the scaffold was loaded with MSCs infected with adeno-Lhx8, GI-Gal4DBD, LOV-VP16, and BMP2-shLhx8.

Conclusions: Together, our study revealed that optogenetic control of the master genes for mesenchymal stem cell proliferation and differentiation would be such a candidate strategy for precise regenerative medicine.

Advances in Engineering Cells for Cancer Immunotherapy

Cancer immunotherapy aims to utilize the host immune system to kill cancer cells. Recent representative immunotherapies include T-cell transfer therapies, such as chimeric antigen receptor T cell therapy, antibody-based immunomodulator therapies, such as immune checkpoint blockade therapy, and cytokine therapies. Recently developed therapies leveraging engineered cells for immunotherapy against cancers have been reported to enhance antitumor efficacy while reducing side effects. Such therapies range from biologically, chemically and physically -engineered cells to bioinspired and biomimetic nanomedicines. In this review, advances of engineering cells for cancer immunotherapy are summarized, and prospects of this field are discussed.

Injectable hydrogels for the sustained delivery of a HER2-targeted antibody for preventing local relapse of HER2+ breast cancer after breast-conserving surgery

A high risk of local relapse is the main challenge of HER2+ breast cancer after breast-conserving surgery. We aimed to develop a long-acting delivery system for Herceptin, a HER2-targeting antibody, using injectable and thermosensitive hydrogels as the carrier to prevent the local relapse of HER2+ breast tumors while minimizing systemic side effects, especially cardiotoxicity. Methods: Two poly(lactic acid-co-glycolic acid)-b-poly(ethylene glycol)-b-poly(lactic acid-co-glycolic acid) (PLGA-PEG-PLGA) triblock copolymers with different PEG/PLGA proportions were synthesized. Their mixtures with rational mix proportions displayed sol-gel transitions in water with rising of temperature and the Herceptin-loaded hydrogel systems were then prepared. Both the in vivo antitumor and anti-relapse efficacies were evaluated after hypodermic injection of the Herceptin-loaded hydrogel, and the cardiotoxicity was also detected. Results: The gel performance, degradation rate and drug release kinetics of hydrogels were easily adjustable by simply varying the mix proportion. The hydrogel matrix with a specific mix proportion not only avoided initial burst release but also achieved sustained release of Herceptin in vitro for up to 80 days, which is the longest period of Herceptin delivery that has ever been reported. In vivo biodistribution studies performed in SK-BR-3 tumor-bearing mice revealed that a single hypodermic administration of the Herceptin-loaded hydrogel adjacent to the tumor tissue promoted the intratumoral antibody accumulation. This resulted in a better antitumor efficacy compared to weekly hypodermic injections of Herceptin solution for 28 days. A tumor relapse model was also established by imitative breast-conserving surgery on tumor-bearing mice, and both the single injection of the Herceptin-loaded hydrogel and the weekly injection of the Herceptin solution achieved superior anti-relapse efficacy. Furthermore, both antitumor and anti-relapse experiments demonstrated that the weekly pulsed administration of the Herceptin solution caused cardiotoxicity; however, the sustained release of Herceptin from the hydrogel effectively prevented this side effect. Conclusion: The Herceptin-loaded hydrogel has great potential for preventing the relapse of HER2+ breast tumors after breast-conserving surgery with enhanced therapeutic efficacy, improved patient compliance and significantly reduced side effects.