CD29 targeted near-infrared photoimmunotherapy (NIR-PIT) in the treatment of a pigmented melanoma model

Carbonic anhydrase-9-targeted near-infrared photoimmunotherapy as a theranostic modality for clear cell renal cell carcinoma

Carbonic anhydrase-9 (CA9) is highly expressed in clear cell renal cell carcinoma (ccRCC) cells despite no expression in normal kidney tissues. Thus, CA9 has been proposed as a theranostic target for radioligand therapy (RLT). However, ccRCC tends to be radioresistant and may not effectively respond to RLT. Alternatively, CA9 can be targeted for near-infrared photoimmunotherapy (NIR-PIT) of ccRCC. Here, we sought to test NIR-PIT using CA9 in a preclinical model of ccRCC to determine its potential as a therapeutic strategy. Tissue microarray analysis showed that membrane CA9 was expressed in the majority of ccRCC cases. In vitro, CA9-targeted NIR-PIT induced cell membrane damage and cell killing in all CA9-expressing ccRCC cell lines specifically, UOK154, UOK220, and UOK122. In vivo, CA9-targeted NIR-PIT significantly inhibited tumor growth and prolonged survival in UOK154 and UOK220 subcutaneous xenograft models. Notably, 70%-80% of mice achieved complete remission after a single treatment of NIR-PIT. Additionally, remaining tumors after the first NIR-PIT persistently expressed CA9, suggesting that remaining tumors can be treated with repeated NIR-PIT. Furthermore, CA9-targeted NIR-PIT induced significant cytoplasmic damages on ccRCC cells in UOK154 orthotopic xenograft models. In conclusion, CA9-targeted NIR-PIT, which allow for safe and repeated application on the same lesion, is a promising treatment for ccRCC, especially in the management of multiple primary ccRCC (e.g., von Hippel-Lindau syndrome) and oligometastatic ccRCC.

SNAP-Tag-Based Recombinant Photoimmunotherapeutic Agents for the Selective Detection and Killing of Light-Accessible Melanotransferrin-Expressing Melanoma and Triple-Negative Breast Cancer

BACKGROUND

Melanoma and triple negative breast cancer (TNBC) represent the most aggressive skin and breast cancer subtypes and are associated with poor diagnostic and limited therapeutic options leading to poor prognosis. Melanotransferrin/p97 (MTf), initially identified as a tumor-associated antigen (TAA) in melanoma, is overexpressed in various solid tumors, including TNBC. Beyond its high differential expression and dreadful tumorigenic impact, MTf is also associated with chemoresistance development, and its inhibition significantly hampers tumor progression, making MTf a promising target for effective targeted therapies. Near-infrared photoimmunotherapy (NIR-PIT) is an approach that combines the precision of antibodies directed against specific TAA with the phototoxic effects of a light-sensitive photosensitizer (IR700), activated by near-infrared (NIR) light irradiation. This study aimed to generate a novel photoimmunoconjugate to specifically destroy MTf-positive melanoma and TNBC cells in vitro following NIR light irradiation.

METHODS

A single-chain variable fragment (scFv) assembled from anti-MTf antibody L49 was recombinantly fused with the SNAP-tag protein (L49(scFv)-SNAP), capable of irreversible and autocatalytic conjugation to any O(6)-benzylguanine (BG) substrate in a 1:1 stoichiometry. Purified full-length SNAP-tag-based fusion protein (L49(scFv)-SNAP-tag) was either conjugated to a BG-modified fluorescent imaging agent (Alexa 488) to specifically assess its selective binding to MTf-expressing cell lines via confocal imaging and flow cytometry or to a BG-modified light-sensitive photosensitizer (IR700) to evaluate its phototoxic properties using an XTT cell viability assay.

RESULTS

The selective binding and internalization of L49(scFv)-SNAP-Alexa 488 towards MTf-positive melanoma and TNBC cell lines were successfully demonstrated with MTF expression percentages ranging from 52.8 to 83.1. Once confirmed, dose-dependent phototoxicity of L49(scFv)-SNAP-IR700 was achieved on illuminated MTf-positive cell lines showing IC50 values in the nanomolar range (2.20-5.24 nM).

CONCLUSION

This study highlights the therapeutic potential of MTf as a promising target for the diagnosis as well as selective and efficient elimination of NIR-light-accessible melanoma and TNBC by NIR-PIT.

TRIAL REGISTRATION

NCT03769506.

Predictive Factors for the Efficacy of Head and Neck Photoimmunotherapy and Optimization of Treatment Schedules

Background/Aim

Head and neck photoimmunotherapy (HN-PIT) is a promising treatment for unresectable locally advanced or recurrent head and neck cancers. However, the optimal tumor characteristics and treatment schedules remain unclear. This study aimed to identify factors associated with treatment efficacy and assess the effectiveness of treatment schedules.

Patients and Methods

A retrospective cohort study of patients treated with HN-PIT at Aichi Cancer Center Hospital from January 2021 to October 2024 was conducted. Tumor characteristics, treatment cycles, and outcomes were analyzed. The thickness and longest diameter of the tumors were evaluated, and treatment intervals were assessed for their association with complete response (CR).

Results

Among the 19 patients (30 cycles), CR was observed exclusively in local lesions. Smaller and thinner lesions showed significantly better treatment responses. Thinner lesions were more likely to achieve CR after a single cycle, whereas intermediate-thickness tumors often required multiple cycles with shorter intervals. The regional lesions did not achieve CR, even with multiple cycles and shorter intervals. Age was a significant factor influencing CR.

Conclusion

HN-PIT demonstrated promising efficacy for local lesions, particularly for smaller and thinner lesions. Optimizing treatment schedules, including shorter intervals for intermediate lesions, is critical for improving outcomes. Further research is needed to enhance the efficacy for regional lesions and refine treatment schedules.

Tissue factor targeted near-infrared photoimmunotherapy: a versatile therapeutic approach for malignancies

Tissue factor (TF) is a cell surface protein that plays a role in blood clotting but is also commonly expressed in many cancers. Recent research implicated TF in cancer proliferation, metastasis, angiogenesis, and immune escape. Therefore, TF can be considered a viable therapeutic target against cancer. Herein, we developed and tested a TF-targeted near-infrared photoimmunotherapy (NIR-PIT) as a potential treatment for several types of cancer. Tisotumab, a TF antibody, was conjugated to IR700. The efficacy of TF-targeted NIR-PIT was investigated using multiple cancer cell lines (A431; epidermoid carcinoma, HPAF-II; pancreatic adenocarcinoma, HSC-2; oral carcinoma, HT1376-luc; bladder carcinoma, MDAMB231; breast adenocarcinoma, and SKOV3-luc; ovarian serous cystadenocarcinoma) in vitro. In vivo, the efficacy of TF-targeted NIR-PIT was evaluated in HPAF-II and A431 xenograft mouse models. Pathologic changes in these tumors after NIR-PIT were evaluated in these tumor models. All cancer lines demonstrated TF expression in vitro and in vivo. Additionally, TF expression was documented to localize to cancer cells in tumors. In vitro, TF-targeted NIR-PIT caused cell death in a light dose-dependent manner. In vivo, TF-targeted NIR-PIT suppressed tumor growth and improved survival rates compared to controls. Furthermore, in vivo NIR-PIT showed histological signs of cancer cell damage, such as cytoplasmic vacuolation, nuclear dysmorphism, and extracellular leakage of LDHA consistent with cell death. In conclusion, TF-targeted NIR-PIT holds promise as a treatment for multiple cancer models expressing TF, spanning multiple cancer types.

Near-infrared photoimmunotherapy: mechanisms, applications, and future perspectives in cancer research

Photoimmunotherapy (PIT) involves the targeted delivery of a photosensitizer through antibody conjugation, which, upon binding to its cellular target and activation by external irradiation, induces localized toxicity. This approach addresses several limitations of conventional cancer therapies, such as chemo- and radiotherapies, which result in off-target effects that significantly reduce patient quality of life. Furthermore, PIT improves on the challenges encountered with photodynamic therapy (PDT), such as nonspecific localization of the photosensitizer, which often results in unintended toxicities. Although PIT was first proposed in the early 1980s, its clinical applications have been constrained by limitations in antibody engineering, conjugation chemistries, and optical technologies. However, recent advances in antibody-drug conjugate (ADC) research and the emergence of sophisticated laser technologies have greatly benefited the broader applicability of PIT. Notably, the first near-infrared photoimmunotherapy (NIR-PIT) treatment for head and neck cancer has been approved in Japan and is currently in phase III clinical trials in the USA. A significant advantage of PIT over traditional ADCs in cancer management is the agnostic nature of PDT, making it more adaptable to different tumor types. Specifically, PIT can act on cancer stem cells and cancer cells displaying treatment resistance and aggressive phenotypes-a capability beyond the scope of ADCs alone. This review provides an overview of the mechanism of action of NIR-PIT, highlighting its adaptability and application in cancer therapeutics, and concludes by exploring the potential of PIT in advancing cancer treatments.

Phototruncation cell tracking with near-infrared photoimmunotherapy using heptamethine cyanine dye to visualise migratory dynamics of immune cells

BACKGROUND

Noninvasive in vivo cell tracking is valuable in understanding the mechanisms that enhance anti-cancer immunity. We have recently developed a new method called phototruncation-assisted cell tracking (PACT), that uses photoconvertible cell tracking technology to detect in vivo cell migration. This method has the advantages of not requiring genetic engineering of cells and employing tissue-penetrant near-infrared light.

METHODS

We applied PACT to monitor the migration of immune cells between a tumour and its tumour-draining lymph node (TDLN) after near-infrared photoimmunotherapy (NIR-PIT).

FINDINGS

PACT showed a significant increase in the migration of dendritic cells (DCs) and macrophages from the tumour to the TDLN immediately after NIR-PIT. This migration by NIR-PIT was abrogated by inhibiting the sphingosine-1-phosphate pathway or Gαi signaling. These results were corroborated by intranodal immune cell profiles at two days post-treatment; NIR-PIT significantly induced DC maturation and increased and activated the CD8+ T cell population in the TDLN. Furthermore, PACT revealed that NIR-PIT significantly enhanced the migration of CD8+ T cells from the TDLN to the tumour four days post-treatment, which was consistent with the immunohistochemical assessment of tumour-infiltrating lymphocytes and tumour regression.

INTERPRETATION

Immune cells dramatically migrated between the tumour and TDLN following NIR-PIT, indicating its potential as an immune-stimulating therapy. Also, PACT is potentially applicable to a wide range of immunological research.

FUNDING

This work was supported by the Intramural Research Program of the National Institutes of Health, National Cancer Institute, Centre for Cancer Research (grant number: ZIA BC011513 and ZIA BC011506).

Near-infrared photoimmunotherapy targeting Nectin-4 in a preclinical model of bladder cancer

Enfortumab vedotin (EV), an antibody-drug conjugate (ADC) that targets Nectin-4, has shown promising results in the treatment of bladder cancer. However, multiple resistance mechanisms that are unique to ADCs limit the therapeutic potential of EV in clinical practice. Here, we developed and tested a Nectin-4-targeted near-infrared photoimmunotherapy (NIR-PIT) that utilizes the same target as EV but utilizes a distinct cytotoxic and immunotherapeutic pathway in preclinical models of bladder cancer. NIR-PIT was effective in vitro against luminal subtype human bladder cancer cell lines (RT4, RT112, MGH-U3, SW780, and HT1376-luc), but not against other subtype cell lines (UMUC3 and T24). In vivo, the tumor site was clearly visible by Nectin-4-IR700 fluorescence 24 h after its administration, suggesting the potential as an intraoperative imaging modality. NIR-PIT significantly suppressed tumor growth and prolonged survival in SW780 and RT112 xenograft models. Weekly treatment with NIR-PIT further improved tumor control in RT112 xenograft models. The effectiveness of NIR-PIT was also confirmed in HT1376-luc orthotopic xenograft models. Histological analysis verified that NIR-PIT induced a significant pathologic response. Taken together, Nectin-4-targeted NIR-PIT shows promise as a treatment for luminal subtype bladder cancers.

A microneedle patch realizes weight loss through photothermal induction of fat browning

As a globally prevalent disease, obesity leads to many chronic diseases, so it is important to develop safe and effective treatments with fewer side effects and lasting weight loss. In this study, we developed a biodegradable hyaluronic acid microneedle patch loaded with polydopamine nanoparticles and mirabegron, which directly acted on subcutaneous white adipose tissue, and then induced browning of white adipose tissue through mild photothermal therapy. The approach showed excellent browning-promoting ability and biocompatibility. It is noteworthy that the weight of untreated mice increased by 9%, while the weight of obese mice decreased by nearly 19% after photothermal treatment. In addition, when mirabegron was used in combination with photothermal therapy, the weight loss of obese mice was more significant, with a weight loss of about 22%. This microneedle patch exhibited attractive potential for body slimming.

Intratumoral IL15 Improves Efficacy of Near-Infrared Photoimmunotherapy

IL15 is a potent inducer of differentiation and proliferation of CD8+ T and natural killer (NK) cells, making it a promising candidate for cancer immunotherapy. However, limited efficacy of systemic monotherapy utilizing intravenous IL15 suggests the needs for alternative routes of administration or combination treatment with other therapies. Near-infrared photoimmunotherapy (NIR-PIT) is a highly selective anticancer treatment that elicits a massive release of tumor antigens and immunogenic signals. Here, we investigated whether intratumoral IL15 can enhance the effectiveness of cancer cell-targeted NIR-PIT using syngeneic murine tumor models. Intratumoral injection of IL15 was more effective than intraperitoneal IL15 in vivo in suppressing tumor growth and inducing intratumoral immune responses. When the efficacy of CD44-targeted NIR-PIT was compared in vivo between IL15-secreting MC38 (hIL15-MC38) and parental MC38 tumors, the hIL15-MC38/NIR-PIT group showed the best tumor growth inhibition and survival. In addition, the hIL15-MC38/NIR-PIT group showed significant dendritic cell maturation and significant increases in the number and Granzyme B expression of tumor-infiltrating CD8+ T, NK, and natural killer T cells compared with the treated parental line. Furthermore, intratumoral IL15 injection combined with CD44-targeted NIR-PIT showed significant tumor control in MC38 and Pan02-luc tumor models. In bilateral tumor models, CD44-targeted NIR-PIT in hIL15-MC38 tumors significantly suppressed the growth of untreated MC38 tumors, suggesting abscopal effects. Mice that achieved complete response after the combination therapy completely rejected later tumor rechallenge. In conclusion, local IL15 administration synergistically improves the efficacy of cancer cell-targeted NIR-PIT probably by inducing stronger anticancer immunity, indicating its potential as an anticancer treatment strategy.

Near Infrared Photoimmunotherapy: A Review of Recent Progress and Their Target Molecules for Cancer Therapy

Near infrared photoimmunotherapy (NIR-PIT) is a newly developed molecular targeted cancer treatment, which selectively kills cancer cells or immune-regulatory cells and induces therapeutic host immune responses by administrating a cancer targeting moiety conjugated with IRdye700. The local exposure to near-infrared (NIR) light causes a photo-induced ligand release reaction, which causes damage to the target cell, resulting in immunogenic cell death (ICD) with little or no side effect to the surrounding normal cells. Moreover, NIR-PIT can generate an immune response in distant metastases and inhibit further cancer attack by combing cancer cells targeting NIR-PIT and immune regulatory cells targeting NIR-PIT or other cancer treatment modalities. Several recent improvements in NIR-PIT have been explored such as catheter-driven NIR light delivery, real-time monitoring of cancer, and the development of new target molecule, leading to NIR-PIT being considered as a promising cancer therapy. In this review, we discuss the progress of NIR-PIT, their mechanism and design strategies for cancer treatment. Furthermore, the overall possible targeting molecules for NIR-PIT with their application for cancer treatment are briefly summarised.

Near-Infrared Photoimmunotherapy Targeting Podoplanin-Expressing Cancer Cells and Cancer-Associated Fibroblasts

Near-infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment that uses an antibody-IRDye700DX (IR700) conjugate that binds to a target followed by the application of NIR light that results in dramatic changes in solubility of the conjugate leading to rapid cell membrane damage and highly immunogenic cell death. NIR-PIT has been used clinically in treating advanced head and neck cancers using an anti-EGFR antibody-IR700 conjugate and has been conditionally approved for clinical use in Japan. NIR-PIT can be employed using a wide range of targeting antibodies. Podoplanin (PDPN), also known as gp38, is a 38 kDa type-1 transmembrane protein associated with lymphatic vessels. In cancer cells and cancer-associated fibroblasts (CAFs), PDPN expression has been widely reported and correlates with poor outcomes in several cancer types. In this study, we evaluated the efficacy of PDPN-targeted NIR-PIT in syngenetic mouse models of cancer. PDPN-targeted NIR-PIT destroyed PDPN-expressing cancer cells and CAFs selectively, suppressing tumor progression and prolonging survival with minimal damage to lymphatic vessels compared with the control group. Interestingly, PDPN-targeted NIR-PIT also exerted a therapeutic effect by targeting CAFs in tumor models which do not express in cancer cells. Furthermore, increased cytotoxic T cells in the tumor bed after PDPN-targeted NIR-PIT were observed, suggesting enhanced host antitumor immunity. Thus, PDPN-targeted NIR-PIT is a promising new cancer therapy strategy for PDPN-expressing cancer cells and CAFs.

Research progress in inducing immunogenic cell death of tumor cells

Immunogenic cell death (ICD) is a regulated cell death (RCD) pathway. In response to physical and chemical signals, tumor cells activate specific signaling pathways that stimulate stress responses in the endoplasmic reticulum (ER) and expose damage-associated molecular patterns (DAMPs), which promote antitumor immune responses. As a result, the tumor microenvironment is altered, and many tumor cells are killed. The ICD response in tumor cells requires inducers. These inducers can be from different sources and contribute to the development of the ICD either indirectly or directly. The combination of ICD inducers with other tumor treatments further enhances the immune response in tumor cells, and more tumor cells are killed; however, it also produces side effects of varying severity. New induction methods based on nanotechnology improve the antitumor ability and significantly reduces side effects because they can target tumor cells precisely. In this review, we introduce the characteristics and mechanisms of ICD responses in tumor cells and the DAMPs associated with ICD responses, summarize the current methods of inducing ICD response in tumor cells in five distinct categories: chemical sources, physical sources, pathogenic sources, combination therapies, and innovative therapies. At the same time, we introduce the limitations of current ICD inducers and make a summary of the use of ICD responses in clinical trials. Finally, we provide an outlook on the future of ICD inducer development and provide some constructive suggestions.

Near-infrared photoimmunotherapy: design and potential applications for cancer treatment and beyond

Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed cancer treatment modality based on a target-specific photosensitizer conjugate (TSPC) composed of an NIR phthalocyanine photosensitizer and an antigen-specific recognition system. NIR-PIT has predominantly been used for targeted therapy of tumors via local irradiation with NIR light, following binding of TSPC to antigen-expressing cells. Physical stress-induced membrane damage is thought to be a major mechanism underlying NIR-PIT-triggered photokilling. Notably, NIR-PIT can rapidly induce immunogenic cell death and activate the adaptive immune response, thereby enabling its combination with immune checkpoint inhibitors. Furthermore, NIR-PIT-triggered “super-enhanced permeability and retention” effects can enhance drug delivery into tumors. Supported by its potential efficacy and safety, NIR-PIT is a rapidly developing therapeutic option for various cancers. Hence, this review seeks to provide an update on the (i) broad range of target molecules suitable for NIR-PIT, (ii) various types of receptor-selective ligands for designing the TSPC “magic bullet,” (iii) NIR light parameters, and (iv) strategies for enhancing the efficacy of NIR-PIT. Moreover, we review the potential application of NIR-PIT, including the specific design and efficacy in 19 different cancer types, and its clinical studies. Finally, we summarize possible NIR-PIT applications in noncancerous conditions, including infection, pain, itching, metabolic disease, autoimmune disease, and tissue engineering.

Disialoganglioside GD2-Targeted Near-Infrared Photoimmunotherapy (NIR-PIT) in Tumors of Neuroectodermal Origin

Disialoganglioside (GD2) is a subtype of glycolipids that is highly expressed in tumors of neuroectodermal origins, such as neuroblastoma and osteosarcoma. Its limited expression in normal tissues makes GD2 a potential target for precision therapy. Several anti-GD2 monoclonal antibodies are currently in clinical use and have had moderate success. Near-infrared photoimmunotherapy (NIR-PIT) is a cancer therapy that arms antibodies with IRDye700DX (IR700) and then exposes this antibody-dye conjugate (ADC) to NIR light at a wavelength of 690 nm. NIR light irradiation induces a profound photochemical response in IR700, resulting in protein aggregates that lead to cell membrane damage and death. In this study, we examined the feasibility of GD2-targeted NIR-PIT. Although GD2, like other glycolipids, is only located in the outer leaflet of the cell membrane, the aggregates formation exerted sufficient physical force to disrupt the cell membrane and kill target cells in vitro. In in vivo studies, tumor growth was significantly inhibited after GD2-targeted NIR-PIT, resulting in prolonged survival. Following GD2-targeted NIR-PIT, activation of host immunity was observed. In conclusion, GD2-targeted NIR-PIT was similarly effective to the conventional protein-targeted NIR-PIT. This study demonstrates that membrane glycolipid can be a new target of NIR-PIT.

Near-Infrared Photoimmunotherapy (NIR-PIT) in Urologic Cancers

Near-infrared photoimmunotherapy (NIR-PIT) is a novel molecularly-targeted therapy that selectively kills cancer cells by systemically injecting an antibody-photoabsorber conjugate (APC) that binds to cancer cells, followed by the application of NIR light that drives photochemical transformations of the APC. APCs are synthesized by selecting a monoclonal antibody that binds to a receptor on a cancer cell and conjugating it to IRDye700DX silica-phthalocyanine dye. Approximately 24 h after APC administration, NIR light is delivered to the tumor, resulting in nearly-immediate necrotic cell death of cancer cells while causing no harm to normal tissues. In addition, NIR-PIT induces a strong immunologic effect, activating anti-cancer immunity that can be further boosted when combined with either immune checkpoint inhibitors or immune suppressive cell-targeted (e.g., regulatory T cells) NIR-PIT. Currently, a global phase III study of NIR-PIT in recurrent head and neck squamous cell carcinoma is ongoing. The first APC and NIR laser systems were approved for clinical use in September 2020 in Japan. In the near future, the clinical applications of NIR-PIT will expand to other cancers, including urologic cancers. In this review, we provide an overview of NIR-PIT and its possible applications in urologic cancers.