Project description:PurposeNear-infrared photoimmunotherapy (NIR-PIT) is a localized molecular cancer therapy combining a photosensitizer-conjugated mAb and light energy. CD47 is an innate immune checkpoint widely expressed on bladder cancer cells, but absent from luminal normal urothelium. Targeting CD47 for NIR-PIT has the potential to selectively induce cancer cell death and minimize damage to normal urothelium.Experimental designThe cytotoxic effect of NIR-PIT with anti-CD47-IR700 was investigated in human bladder cancer cell lines and primary human bladder cancer cells derived from fresh surgical samples. Phagocytosis assays were performed to evaluate macrophage activity after NIR-PIT. Anti-CD47-IR700 was administered to murine xenograft tumor models of human bladder cancer for in vivo molecular imaging and NIR-PIT.ResultsCytotoxicity in cell lines and primary bladder cancer cells significantly increased in a light-dose-dependent manner with CD47-targeted NIR-PIT. Phagocytosis of cancer cells significantly increased with NIR-PIT compared with antibody alone (P = 0.0002). In vivo fluorescence intensity of anti-CD47-IR700 in tumors reached a peak 24-hour postinjection and was detectable for at least 14 days. After a single round of CD47-targeted NIR-PIT, treated animals showed significantly slower tumor growth compared with controls (P < 0.0001). Repeated CD47-targeted NIR-PIT treatment further slowed tumor growth (P = 0.0104) and improved survival compared with controls.ConclusionsCD47-targeted NIR-PIT increased direct cancer cell death and phagocytosis resulting in inhibited tumor growth and improved survival in a murine xenograft model of human bladder cancer.
Project description:Transurethral resection of bladder tumor (TURBT) followed by intravesical therapy remains the most effective strategy for the management of non-muscle-invasive bladder cancer worldwide. TURBT has two purposes: to remove all visible tumors and to obtain tumor specimens for histopathological analysis. However, the detection of flat and small malignant lesions under white-light cystoscopy is extremely challenging, and residual lesions are still the main reason for the high recurrence rate of bladder cancer. We hypothesized that visual enhancement of malignant lesions using targeted optical molecular imaging could potentially highlight residual tumors in the bladder during surgery, and near-infrared photoimmunotherapy (NIR-PIT) could kill exfoliated cancer cells and residual tumors. A mouse model of complete or partial bladder tumor resection was established under the guidance of optical molecular imaging mediated by indocyanine green and anti-CD47-Alexa Fluor 790, respectively. Once the tumor recurred, mouse model received repeated CD47-targeted NIR-PIT. After complete resection, there was no tumor recurrence. Furthermore, the growth rate of recurrent tumor decreased significantly after repeated NIR-PIT. Therefore, CD47-targeted optical molecular imaging can potentially assist urologists to detect and remove all tumors, and repeated NIR-PIT shows the potential to reduce tumor recurrence rates and inhibit the growth of recurrent tumor.
Project description:Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed cancer therapy that targets cancer cells using a monoclonal antibody-photon absorber conjugate (APC) that is bound to the target cell surface. Subsequent application of low levels of NIR light results in immediate cancer cell death. The anti-tumor effect of NIR-PIT in immunocompromised mice depends on immediate cancer cell death; therefore, the efficacy increases in a light-dose-dependent manner. However, NIR-PIT also induces a strong anti-tumor immune activation in immunocompetent mice that begins soon after therapy. Thus, it may be possible to reduce the light dose, which might otherwise cause local edema while maintaining therapeutic efficacy. In this study, we determined the optimal dose of NIR light in NIR-PIT based on a comparison of the therapeutic and adverse effects. Either one of two monoclonal antibodies (mAbs) against human epidermal growth factor receptor (hEGFR), Cetuximab or Panitumumab, were conjugated with a photo-absorbing chemical, IRDye700DX (IR700), and then injected in hEGFR-expressing mEERL (mEERL-hEGFR) tumor-bearing C57BL/6 immunocompetent mice or A431-GFP-luc tumor-bearing athymic immunocompromised mice. NIR light was varied between 0 to 100 J/cm2 one day after administration of APC. In an immunocompromised mouse model, tumor growth was inhibited in a light-dose-dependent manner, yet extensive local edema and weight loss were observed at 100 J/cm2. On the other hand, in an immunocompetent mouse model using the mEERL-hEGFR cell line, maximal tumor response was achieved at 50 J/cm2, with a commensurate decrease in local edema. In this study, we show that a relatively low dose of NIR light is sufficient in an immunocompetent mouse model and avoids side effects seen with higher light doses required in immunocompetent mice. Thus, light dosing can be optimized in NIR-PIT based on the expected immune response.
Project description:Near-infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment that uses an antibody-photo-absorber conjugate (APC) composed of a targeting monoclonal antibody conjugated with a photoactivatable phthalocyanine-derivative dye, IRDye700DX (IR700). APCs injected into the body can bind to cancer cells where they are activated by local exposure to NIR light typically delivered by a NIR laser. NIR light alters the APC chemical conformation inducing damage to cancer cell membranes, resulting in necrotic cell death within minutes of light exposure. NIR-PIT selectivity kills cancer cells by immunogenic cell death (ICD) with minimal damage to adjacent normal cells thus, leading to rapid recovery by the patient. Moreover, since NIR-PIT induces ICD only on cancer cells, NIR-PIT initiates and activates antitumor host immunity that could be further enhanced when combined with immune checkpoint inhibition. NIR-PIT induces dramatic changes in the tumor vascularity causing the super-enhanced permeability and retention (SUPR) effect that dramatically enhances nanodrug delivery to the tumor bed. Currently, a worldwide Phase 3 study of NIR-PIT for recurrent or inoperable head and neck cancer patients is underway. In September 2020, the first APC and accompanying laser system were conditionally approved for clinical use in Japan. In this review, we introduce NIR-PIT and the SUPR effect and summarize possible applications of NIR-PIT in a variety of cancers.
Project description:Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed cancer treatment that utilizes an antibody-photoabsorber-conjugate (AbPC) combined with NIR light. The AbPC is injected and binds to the tumor whereupon NIR light irradiation causes a photochemical reaction that selectively kills cancer cells. NIR-PIT is ideal for surface-located skin cancers such as melanoma. However, there is concern that the pigment in melanoma lesions could interfere with light delivery, rendering treatment ineffective. We investigated the efficacy of CD29- and CD44-targeted NIR-PIT (CD29-PIT and CD44-PIT, respectively) in the B16 melanoma model, which is highly pigmented. While CD29-PIT and CD44-PIT killed B16 cells in vitro and in vivo, CD29-PIT suppressed tumor growth more efficiently. Ki67 expression showed that cells surviving CD29-PIT were less proliferative, suggesting that CD29-PIT was selective for more proliferative cancer cells. CD29-PIT did not kill immune cells, whereas CD44-PIT killed both T and NK cells and most myeloid cells, including DCs, which could interfere with the immune response to NIR-PIT. The addition of anti-CTLA4 antibody immune checkpoint inhibitor (ICI) to CD29-PIT increased the infiltration of CD8 T cells and enhanced tumor suppression with prolonged survival. Such effects were less prominent when the anti-CTLA4 ICI was combined with CD44-PIT. The preservation of immune cells in the tumor microenvironment (TME) after CD29-PIT likely led to a better response when combined with anti-CTLA4 treatment. We conclude that NIR-PIT can be performed in pigmented melanomas and that CD29 is a promising target for NIR-PIT, which is amenable to combination therapy with other immunotherapies.
Project description:Malignant pleural mesothelioma (MPM) has extremely limited treatment despite a poor prognosis. Moreover, molecular targeted therapy for MPM has not yet been implemented; thus, a new targeted therapy is highly desirable. Near-infrared photoimmunotherapy (NIR-PIT) is a recently developed cancer therapy that combines the specificity of antibodies for targeting tumors with toxicity induced by the photoabsorber after exposure to NIR-light. In this study, we developed a new phototherapy targeting podoplanin (PDPN) for MPM with the use of both NIR-PIT and an anti-PDPN antibody, NZ-1. An antibody-photosensitizer conjugate consisting of NZ-1 and phthalocyanine dye was synthesized. In vitro NIR-PIT-induced cytotoxicity was measured with both dead cell staining and luciferase activity on various MPM cell lines. In vivo NIR-PIT was examined in both the flank tumor and orthotopic mouse model with in vivo real-time imaging. In vitro NIR-PIT-induced cytotoxicity was NIR-light dose dependent. In vivo NIR-PIT led to significant reduction in both tumor volume and luciferase activity in a flank model (p < 0.05, NIR-PIT group versus NZ-1-IR700 group). The PDPN-targeted NIR-PIT resulted in a significant antitumor effect in an MPM orthotopic mouse model (p < 0.05, NIR-PIT group versus NZ-1-IR700 group). This study suggests that PDPN-targeted NIR-PIT could be a new promising treatment for MPM.
Project description:This Account is the first comprehensive review article on the newly developed, photochemistry-based cancer therapy near-infrared (NIR) photoimmunotherapy (PIT). NIR-PIT is a molecularly targeted phototherapy for cancer that is based on injecting a conjugate of a near-infrared, water-soluble, silicon-phthalocyanine derivative, IRdye700DX (IR700), and a monoclonal antibody (mAb) that targets an expressed antigen on the cancer cell surface. Subsequent local exposure to NIR light turns on this photochemical "death" switch, resulting in the rapid and highly selective immunogenic cell death (ICD) of targeted cancer cells. ICD occurs as early as 1 min after exposure to NIR light and results in irreversible morphologic changes only in target-expressing cells based on the newly discovered photoinduced ligand release reaction that induces physical changes on conjugated antibody/antigen complex resulting in functional damage on cell membrane. Meanwhile, immediately adjacent receptor-negative cells are totally unharmed. Because of its highly targeted nature, NIR-PIT carries few side effects and healing is rapid. Evaluation of the tumor microenvironment reveals that ICD induced by NIR-PIT results in rapid maturation of immature dendritic cells adjacent to dying cancer cells initiating a host anticancer immune response, resulting in repriming of polyclonal CD8+T cells against various released cancer antigens, which amplifies the therapeutic effect of NIR-PIT. NIR-PIT can target and treat virtually any cell surface antigens including cancer stem cell markers, that is, CD44 and CD133. A first-in-human phase 1/2 clinical trial of NIR-PIT using cetuximab-IR700 (RM1929) targeting EGFR in inoperable recurrent head and neck cancer patients successfully concluded in 2017 and led to "fast tracking" by the FDA and a phase 3 trial ( https://clinicaltrials.gov/ct2/show/NCT03769506 ) that is currently underway in 3 countries in Asia, US/Canada, and 4 countries in EU. The next step for NIR-PIT is to further exploit the immune response. Preclinical research in animals with intact immune systems has shown that NIT-PIT targeting of immunosuppressor cells within the tumor, such as regulatory T-cells, can further enhance tumor-cell-selective systemic host-immunity leading to significant responses in distant metastatic tumors, which are not treated with light. By combining cancer-targeting NIR-PIT and immune-activating NIR-PIT or other cancer immunotherapies, NIR-PIT of a local tumor, could lead to responses in distant metastases and may also inhibit recurrences due to activation of systemic anticancer immunity and long-term immune memory without the systemic autoimmune adverse effects often associated with immune checkpoint inhibitors. Furthermore, NIR-PIT also enhances nanodrug delivery into tumors up to 24-fold superior to untreated tumors with conventional EPR effects by intensively damaging cancer cells behind tumor vessels. We conclude by describing future advances in this novel photochemical cancer therapy that are likely to further enhance the efficacy of NIR-PIT.
Project description:Near-infrared photoimmunotherapy (NIR-PIT) is a molecularly targeted cancer phototherapy that is based on injecting a conjugate of a silicon-phthalocyanine derivative, IRdye 700DX (IR700), and a monoclonal antibody that targets an expressed antigen on the cancer cell surface. Subsequent local exposure to NIR light results in the rapid and highly selective immunogenic cell death of targeted cancer cells. Because many cancers grow in bones through which light does not penetrate well, the goal of this study was to determine if NIR-PIT can effectively treat cancers in bone. A bovine rib was used as a bone sample. Because the sample's NIR light transmittance was shown to be approximately 4.52% in preliminary tests, it was hypothesized that a maximum radiation dosage of 128 and 1500 J/cm2 would be sufficient to induce cell death in in vitro target cells and in vivo mouse tumor models, respectively. Cell viability was measured through bioluminescence studies comparing relative luciferase activity, as well as a cytotoxicity assay. In the in vitro model, tumor cell viability was significantly decreased after 64 and 128 J/cm2 NIR light irradiation through the bone. An in vivo mouse tumor model also showed that 1500 J/cm2 NIR light irradiation through the bone significantly reduced tumor viability at both 24 and 48 hours posttreatment compared to the control group (P = .026 and .040 respectively). Therefore, despite limitations in light transmission, NIR-PIT nevertheless is capable of effectively treating cancers within bone.