Photodynamic therapy and anti-tumour immunity Hamblin, Michael R; Castano, Ana P; Mroz, Pawel
Nature reviews. Cancer,
200607, 2006-Jul, 2006-7-00, 20060701, Letnik:
6, Številka:
7
Journal Article
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Photodynamic therapy (PDT) uses non-toxic photosensitizers and harmless visible light in combination with oxygen to produce cytotoxic reactive oxygen species that kill malignant cells by apoptosis ...and/or necrosis, shut down the tumour microvasculature and stimulate the host immune system. In contrast to surgery, radiotherapy and chemotherapy that are mostly immunosuppressive, PDT causes acute inflammation, expression of heat-shock proteins, invasion and infiltration of the tumour by leukocytes, and might increase the presentation of tumour-derived antigens to T cells.
Cell-based therapies are emerging as effective agents against cancer and other diseases. As autonomous "living drugs," these therapies lack precise control. Chimeric antigen receptor (CAR) T cells ...effectively target hematologic malignancies but can proliferate rapidly and cause toxicity. We developed ON and OFF switches for CAR T cells using the clinically approved drug lenalidomide, which mediates the proteasomal degradation of several target proteins by inducing interactions between the CRL4
E3 ubiquitin ligase and a C2H2 zinc finger degron motif. We performed a systematic screen to identify "super-degron" tags with enhanced sensitivity to lenalidomide-induced degradation and used these degradable tags to generate OFF-switch degradable CARs. To create an ON switch, we engineered a lenalidomide-inducible dimerization system and developed split CARs that required both lenalidomide and target antigen for activation. Subtherapeutic lenalidomide concentrations controlled the effector functions of ON- and OFF-switch CAR T cells. In vivo, ON-switch split CARs demonstrated lenalidomide-dependent antitumor activity, and OFF-switch degradable CARs were depleted by drug treatment to limit inflammatory cytokine production while retaining antitumor efficacy. Together, the data showed that these lenalidomide-gated switches are rapid, reversible, and clinically suitable systems to control transgene function in diverse gene- and cell-based therapies.
Adoptive cell therapy (ACT) with antigen-specific T cells has shown remarkable clinical success; however, approaches to safely and effectively augment T cell function, especially in solid tumors, ...remain of great interest. Here we describe a strategy to 'backpack' large quantities of supporting protein drugs on T cells by using protein nanogels (NGs) that selectively release these cargos in response to T cell receptor activation. We designed cell surface-conjugated NGs that responded to an increase in T cell surface reduction potential after antigen recognition and limited drug release to sites of antigen encounter, such as the tumor microenvironment. By using NGs that carried an interleukin-15 super-agonist complex, we demonstrated that, relative to systemic administration of free cytokines, NG delivery selectively expanded T cells 16-fold in tumors and allowed at least eightfold higher doses of cytokine to be administered without toxicity. The improved therapeutic window enabled substantially increased tumor clearance by mouse T cell and human chimeric antigen receptor (CAR)-T cell therapy in vivo.
Chimeric antigen receptor (CAR)-T-cell therapy for solid tumors is limited due to heterogeneous target antigen expression and outgrowth of tumors lacking the antigen targeted by CAR-T cells directed ...against single antigens. Here, we developed a bicistronic construct to drive expression of a CAR specific for EGFRvIII, a glioblastoma-specific tumor antigen, and a bispecific T-cell engager (BiTE) against EGFR, an antigen frequently overexpressed in glioblastoma but also expressed in normal tissues. CART.BiTE cells secreted EGFR-specific BiTEs that redirect CAR-T cells and recruit untransduced bystander T cells against wild-type EGFR. EGFRvIII-specific CAR-T cells were unable to completely treat tumors with heterogenous EGFRvIII expression, leading to outgrowth of EGFRvIII-negative, EGFR-positive glioblastoma. However, CART.BiTE cells eliminated heterogenous tumors in mouse models of glioblastoma. BiTE-EGFR was locally effective but was not detected systemically after intracranial delivery of CART.BiTE cells. Unlike EGFR-specific CAR-T cells, CART.BiTE cells did not result in toxicity against human skin grafts in vivo.
Scarring of the kidney is a major public health concern, directly promoting loss of kidney function. To understand the role of microRNA (miRNA) in the progression of kidney scarring in response to ...injury, we investigated changes in miRNA expression in two kidney fibrosis models and identified 24 commonly up-regulated miRNAs. Among them, miR-21 was highly elevated in both animal models and in human transplanted kidneys with nephropathy. Deletion of miR-21 in mice resulted in no overt abnormality. However, miR-21(-/-) mice suffered far less interstitial fibrosis in response to kidney injury, a phenotype duplicated in wild-type mice treated with anti-miR-21 oligonucleotides. Global derepression of miR-21 target mRNAs was readily detectable in miR-21(-/-) kidneys after injury. Analysis of gene expression profiles up-regulated in the absence of miR-21 identified groups of genes involved in metabolic pathways, including the lipid metabolism pathway regulated by peroxisome proliferator-activated receptor-α (Pparα), a direct miR-21 target. Overexpression of Pparα prevented ureteral obstruction-induced injury and fibrosis. Pparα deficiency abrogated the antifibrotic effect of anti-miR-21 oligonucleotides. miR-21 also regulated the redox metabolic pathway. The mitochondrial inhibitor of reactive oxygen species generation Mpv17l was repressed by miR-21, correlating closely with enhanced oxidative kidney damage. These studies demonstrate that miR-21 contributes to fibrogenesis and epithelial injury in the kidney in two mouse models and is a candidate target for antifibrotic therapies.
Tissue colonization (homing) by blood-borne cells critically hinges on the ability of the cells to adhere to vascular endothelium with sufficient strength to overcome prevailing hemodynamic shear ...stress. These adhesive interactions are most effectively engendered via binding of the endothelial lectin E-selectin (CD62E) to its cognate ligand, sialyl Lewis-X (sLeX), displayed on circulating cells. Although chimeric antigen receptor (CAR) T-cell immunotherapy holds promise for treatment of various hematologic and non-hematologic malignancies, there is essentially no information regarding the efficiency of CAR T-cell homing. Accordingly, we performed integrated biochemical studies and adhesion assays to examine the capacity of human CAR T-cells to engage E-selectin. Our data indicate that CAR T-cells do not express sLeX and do not bind E-selectin. However, enforced sLeX display can be achieved on human CAR T-cells by surface fucosylation, with resultant robust E-selectin binding under hemodynamic shear. Importantly, following intravascular administration into mice, fucosylated human CAR-T cells infiltrate marrow with 10-fold higher efficiency than do unfucosylated cells. Collectively, these findings indicate that custom installation of sLeX programs tissue colonization of vascularly administered human CAR T-cells, offering a readily translatable strategy to augment tissue delivery, thereby lowering the pertinent cell dosing and attendant cell production burden, for CAR T-cell immunotherapy applications.
Despite remarkable success in the treatment of hematological malignancies, CAR T-cell therapies for solid tumors have floundered, in large part due to local immune suppression and the effects of ...prolonged stimulation leading to T-cell dysfunction and exhaustion. One mechanism by which gliomas and other cancers can hamper CAR T cells is through surface expression of inhibitory ligands such as programmed cell death ligand 1 (PD-L1). Using the CRIPSR-Cas9 system, we created universal CAR T cells resistant to PD-1 inhibition through multiplexed gene disruption of endogenous T-cell receptor (TRAC), beta-2 microglobulin (B2M) and PD-1 (PDCD1). Triple gene-edited CAR T cells demonstrated enhanced activity in preclinical glioma models. Prolonged survival in mice bearing intracranial tumors was achieved after intracerebral, but not intravenous administration. CRISPR-Cas9 gene-editing not only provides a potential source of allogeneic, universal donor cells, but also enables simultaneous disruption of checkpoint signaling that otherwise impedes maximal antitumor functionality.
HemCon
® bandage is an engineered chitosan acetate preparation used as a hemostatic control dressing, and its chemical structure suggests that it should also be antimicrobial. We tested its ability ...to rapidly kill bacteria in vitro and in mouse models of infected wounds. We used the Gram-negative species
Pseudomonas aeruginosa and
Proteus mirabilis and the Gram-positive
Staphylococcus aureus that had all been stably transduced with the entire bacterial lux operon to allow in vivo bioluminescence imaging. An excisional wound in Balb/c mice was inoculated with 50–250 million cells followed after 30
min by application of HemCon bandage, alginate sponge bandage, silver sulfadiazine cream or no treatment. HemCon was more adhesive to the wound and conformed well to the injury compared to alginate. Animal survival was followed over 15 days with observations of bioluminescence emission and animal activity daily. Chitosan acetate treated mice infected with
P. aeruginosa and
P. mirabilis all survived while those receiving no treatment, alginate and silver sulfadiazine demonstrated 25–100% mortality. Chitosan acetate was much more effective than other treatments in rapidly reducing bioluminescence in the wound consistent with its rapid bactericidal activity in vitro as well as its light-scattering properties.
S. aureus formed only non-lethal localized infections after temporary immunosuppression of the mice but HemCon was again more effective in reducing bioluminescence. The data suggest that chitosan acetate rapidly kills bacteria in the wound before systemic invasion can take place, and is superior to alginate bandage and silver sulfadiazine that may both encourage bacterial growth in the short term.
The use of non-toxic dyes or photosensitizers (PS) in combination with harmless visible light that is known as photodynamic therapy (PDT) has been known for over a hundred years, but is only now ...becoming widely used. Originally developed as a tumor therapy, some of its most successful applications are for non-malignant disease. In a series of three reviews we will discuss the mechanisms that operate in the field of PDT. Part one discusses the recent explosion in discovery and chemical synthesis of new PS. Some guidelines on how to choose an ideal PS for a particular application are presented. The photochemistry and photophysics of PS and the two pathways known as Type I (radicals and reactive oxygen species) and Type II (singlet oxygen) photochemical processes are discussed. To carry out PDT effectively in vivo, it is necessary to ensure sufficient light reaches all the diseased tissue. This involves understanding how light travels within various tissues and the relative effects of absorption and scattering. The fact that most of the PS are also fluorescent allows various optical imaging and monitoring strategies to be combined with PDT. The most important factor governing the outcome of PDT is how the PS interacts with cells in the target tissue or tumor, and the key aspect of this interaction is the subcellular localization of the PS. Examples of PS that localize in mitochondria, lysosomes, endoplasmic reticulum, Golgi apparatus and plasma membranes are given. Finally the use of 5-aminolevulinic acid as a natural precursor of the heme biosynthetic pathway, stimulates accumulation of the PS protoporphyrin IX is described.
Photodynamic therapy (PDT) is a modality for the treatment of cancer involving excitation of nontoxic photosensitizers with harmless visible light-producing cytotoxic reactive oxygen species. PDT ...causes apoptosis and necrosis of tumor cells, destruction of the tumor blood supply, and activation of the immune system. The objective of this study was to compare in an animal model of metastatic cancer PDT alone and PDT combined with low-dose cyclophosphamide (CY) a treatment that has been proposed to deplete regulatory T cells (T-regs) and increase the immune response to some tumors. We used J774 tumors (a highly metastatic reticulum cell sarcoma line) and PDT with benzoporphyrin derivative monoacid ring A, verteporfin for injection (BPD; 1-mg/kg injected i.v. followed after 15 min by 150 J/cm² of 690-nm light). CY (50 or 150 mg/kg i.p.) was injected 48 h before light delivery. PDT alone led to tumor regressions and a survival advantage but no permanent cures were obtained. BPD-PDT in combination with low-dose CY (but not high-dose CY) led to 70% permanent cures. Low-dose CY alone gave no permanent cures but did provide a survival advantage and was shown to reduce CD4+FoxP3+ T-regs in lymph nodes, whereas high-dose CY reduced other lymphocyte classes as well. Cured animals were rechallenged with J774 cells, and the tumors were rejected in 71% of mice. Cured mice had tumor-specific T cells in spleens as determined by a ⁵¹Cr release assay. We conclude that low-dose CY depletes T-regs and potentiates BPD-PDT, leading to tumor cures and memory immunity.
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