Cancer neovasculature-targeted near-infrared photoimmunotherapy (NIR-PIT) for gastric cancer: different mechanisms of phototoxicity compared to cell membrane-targeted NIR-PIT.

BACKGROUND: Near-infrared photoimmunotherapy (NIR-PIT) constitutes a new class of molecular-targeted theranostics utilizing monoclonal antibody (mAb)-photosensitizer conjugates and NIR light. In this study, we developed a new type of NIR-PIT targeting vascular endothelial growth factor receptor 2 (VEGFR-2) expressed on vascular endothelium in an experimental gastric cancer model and evaluated the feasibility by comparing conventional NIR-PIT targeting cancer cell membrane in vitro and in vivo. METHODS: HER2-positive human gastric cancer cells, NCI-N87, were used for the experiments. Anti-HER2 mAb, trastuzumab and anti-VEGFR-2 mAb, DC101 were conjugated to photosensitizer, IR700. Phototoxicity in response to NIR-PIT were investigated in vitro and in vivo. Microvessel densities, as an indicator of angiogenesis, were counted in harvested xenografts after NIR-PIT to elucidate the mechanism. RESULTS: DC101-IR700 did not induce phototoxic effect in vitro because of the absence of expression of VEGFR-2 in NCI-N87 cancer cells. However, it induced an antitumor effect in NCI-N87 xenograft tumors accompanied with damage in tumor neovasculature as determined by decreasing tumor microvessel density, which represents a different mechanism than that of conventional NIR-PIT targeting antigens expressed on the tumor cell membrane. CONCLUSION: We demonstrated a new approach of NIR-PIT utilizing a target on vascular endothelium, such as VEGFR-2, and this treatment might lead to the development of a new therapeutic strategy for human gastric cancer.

Photoimmunotherapy targeting biliary-pancreatic cancer with humanized anti-TROP2 antibody.

Photoimmunotherapy (PIT) is a new type of tumor-specific treatment utilizing monoclonal antibody (mAb)-photosensitizer conjugates and near-infrared (NIR) light irradiation. One potential PIT target, the type I transmembrane protein TROP2, is expressed at high levels in many cancers, including pancreatic carcinoma (PC) and cholangiocarcinoma (CC), in which its expression is correlated with poor prognosis and tumor aggressiveness. In this study, we assessed the efficacy of PIT utilizing newly developed humanized anti-TROP2 mAb conjugated to the photosensitizer IR700 (TROP2-IR700) for PC and CC. Immunohistochemistry on PC and CC tissue microarrays confirmed that TROP2 is overexpressed in about half of PC and CC specimens. Using cultured PC and CC cells, TROP2-IR700 localized TROP2-specific and target-specific cell killing was observed after NIR light irradiation. In addition, TROP2-IR700 was localized to mouse xenograft tumors expressing TROP2 after intravenous injection. PC and CC xenograft tumor growth was significantly inhibited by TROP2-targeted PIT relative to controls. The efficacy of TROP2-targeted PIT in vitro and against xenografted tumors in vivo suggests promise as a therapy for human PC and CC, both of which currently have dismal prognoses and limited therapeutic options.

Randomized Trial of Vitamin D Supplementation to Prevent Seasonal Influenza and Upper Respiratory Infection in Patients With Inflammatory Bowel Disease.

BACKGROUND: We evaluated whether oral vitamin D supplementation during the winter and early spring reduces the incidence of influenza and upper respiratory infections in patients with inflammatory bowel disease (IBD). METHODS: A randomized, double-blind, controlled trial was conducted to compare the effects of vitamin D supplementation (500 IU/day) and a placebo. The primary outcome was the incidence of influenza; the secondary outcome was the incidence of upper respiratory infection. Prespecified subgroup analyses were performed according to 25-hydroxyvitamin D (25-OHD) levels (low <20 ng/mL or high ≥20 ng/mL) and whether ulcerative colitis (UC) or Crohn's disease (CD) was present. We also used the Lichtiger clinical activity index for patients with UC and the Crohn's Disease Activity Index (CDAI) for patients with CD before and after interventions. RESULTS: We included 223 patients with IBD and randomized them into 2 groups: vitamin D supplementation (n = 108) and placebo (n = 115). The incidence of influenza did not differ between the groups. However, the incidence of upper respiratory infection was significantly lower in the vitamin D group (relative risk [RR], 0.59; 95% confidence interval (CI), 0.35-0.98; P = 0.042). This effect was enhanced in the low 25-OHD level subgroup (RR, 0.36; 95% CI, 0.14-0.90; P = 0.02). With respect to adverse events, the Lichtiger clinical activity index score was significantly worse in the vitamin D group (P = 0.002) and remained significant only in the high 25-OHD level subgroup. CONCLUSIONS: Vitamin D supplementation may have a preventative effect against upper respiratory infection in patients with IBD but may worsen the symptoms of UC.

Near-Infrared Photochemoimmunotherapy by Photoactivatable Bifunctional Antibody-Drug Conjugates Targeting Human Epidermal Growth Factor Receptor 2 Positive Cancer.

Near-infrared photoimmunotherapy (NIR-PIT) is a new class of molecular targeted cancer therapy based on antibody-photoabsorber conjugates and NIR light irradiation. Recent studies have shown effective tumor control, including that of human epidermal growth factor receptor 2 (HER2)-positive cancer, by selective molecular targeting with NIR-PIT. However, the depth of NIR light penetration limits its use. Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate consisting of the monoclonal antibody trastuzumab linked to the cytotoxic agent maytansinoid DM1. Here, we developed bifunctional antibody-drug-photoabsorber conjugates, T-DM1-IR700, that can work as both NIR-PIT and chemoimmunotherapy agents. We evaluated the feasibility of T-DM1-IR700-mediated NIR light irradiation by comparing the in vitro and in vivo cytotoxic efficacy of trastuzumab-IR700 (T-IR700)-mediated NIR light irradiation in HER2-expressing cells. T-IR700 and T-DM1-IR700 showed almost identical binding to HER2 in vitro and in vivo. Owing to the presence of internalized DM1 in the target cells, NIR-PIT using T-DM1-IR700 tended to induce greater cytotoxicity than that of NIR-PIT using T-IR700 in vitro. In vivo NIR-PIT using T-DM1-IR700 did not show a superior antitumor effect to NIR-PIT using T-IR700 in subcutaneous small-tumor models, which could receive sufficient NIR light. In contrast, NIR-PIT using T-DM1-IR700 tended to reduce the tumor volume and showed significant prolonged survival compared to NIR-PIT using T-IR700 in large-tumor models that could not receive sufficient NIR light. We successfully developed a T-DM1-IR700 conjugate that has a similar immunoreactivity to the parental antibody with increased cytotoxicity due to DM1 and potential as a new NIR-PIT agent for targeting tumors that are large and inaccessible to sufficient NIR light irradiation to activate the photoabsorber IR700.

Molecular targeted photoimmunotherapy for HER2-positive human gastric cancer in combination with chemotherapy results in improved treatment outcomes through different cytotoxic mechanisms.

BACKGROUND: Photoimmunotherapy (PIT) is a novel type of molecular optical imaging-guided cancer phototherapy based on a monoclonal antibody conjugated to a photosensitizer, IR700, in combination with near-infrared (NIR) light. PIT rapidly causes target-specific cell death by inducing cell membrane damages and appears to be highly effective; however, we have previously demonstrated that tumor recurrences were eventually seen in PIT-treated mice, likely owing to inhomogeneous mAb-IR700 conjugate distribution in the tumor, thus limiting the effectiveness of PIT as a monotherapy. Here, we examined the effects of human epidermal growth factor-2 (HER2)-targeted PIT in combination with 5-fluorouracil (5-FU) compared to PIT alone for HER2-expressing human gastric cancer cells. METHODS: NCI-N87 cells, HER2-positive human gastric cancer cells, were used for the experiments. Trastuzumab, a monoclonal antibody directed against HER2, was conjugated to IR700. To assess the short-term cytotoxicity and examine the apoptotic effects upon addition of 5-FU in vitro, we performed LIVE/DEAD and caspase-3 activity assays. Additionally, to explore the effects on long-term growth inhibition, trypan blue dye exclusion assay was performed. NCI-N87 tumor xenograft models were prepared for in vivo treatment studies and the tumor-bearing mice were randomized into various treatment groups. RESULTS: Compared to PIT alone, the combination of HER2-targeted PIT and 5-FU rapidly induced significant cytotoxicity in both the short-term and long-term cytotoxicity assays. While both 5-FU and/or trastuzumab-IR700 conjugate treatment induced an increase in caspase-3 activity, there was no additional increase in caspase-3 activity upon NIR light irradiation after incubation with 5-FU and/or trastuzumab-IR700. The combination of HER2-targeted PIT and 5-FU resulted in greater and longer tumor growth inhibition than PIT monotherapy in vivo. This combined effect of PIT and 5-FU is likely owing to their different mechanisms of inducing tumor cell death, namely necrotic membrane damage by PIT and apoptotic cell death by 5-FU and trastuzumab. CONCLUSIONS: PIT in combination with 5-FU resulted in enhanced antitumor effects compared to PIT alone for HER2-expressing human gastric cancer in vitro and in vivo. This combination photoimmunochemotherapy represents a practical method for treating human gastric cancer and should be investigated further in the clinical setting.

Efficacy of zinc-carnosine chelate compound, Polaprezinc, enemas in patients with ulcerative colitis.

OBJECTIVES: Ulcerative colitis (UC) is a chronic, relapsing and remitting intestinal inflammatory disorder. Zinc is known to be efficacious for the repair of damaged tissue and has been shown to protect against gastric ulceration. This study focused on Polaprezinc (PZ), N-(3-aminopropionyl)-L-histidinato zinc, which accelerates ulcer healing through actions such as prostaglandin-independent cytoprotection and antioxidative activity. METHODS: In this randomized, placebo-controlled, investigator-blinded trial, 28 patients with active UC at The Jikei University Hospital were randomly divided into two groups: one treated with a 150 mg PZ enema (n = 18) and the other not treated with a PZ enema (n = 10). All patients received usual induction therapy. Clinical symptoms, endoscopic findings and histological findings were evaluated at entry and one week later. RESULTS: In the PZ group, modified Matts' endoscopic scores were significantly improved after treatment compared to baseline in the rectum (p = 0.004), sigmoid colon (p = 0.03) and descending colon (p = 0.04). In the non-PZ group, scores were not significantly improved in the rectum (p = 0.14) and descending colon (p = 0.34), but were improved in the sigmoid colon (p = 0.04). In the PZ group, the Mayo scores at baseline and at Day 8 were 9.1 ± 1.6 and 5.8 ± 2.7 (p = 0.00004), respectively, and in the placebo group, the scores were 8.9 ± 1.7 and 7.4 ± 2.1 (p = 0.009), respectively. Clinical response or remission was significantly better in the PZ group (71%) than in the placebo group (10%). CONCLUSIONS: A zinc-carnosine chelate compound, PZ, enema may become a useful new add-on treatment to accelerate mucosal healing in UC.

Expression of urocortin III/stresscopin in human heart and kidney.

Urocortin III (Ucn III)/stresscopin (SCP) is a novel peptide of the corticotropin-releasing factor (CRF) family and is a specific ligand for the CRF type 2 receptor. We wished to clarify whether Ucn III/SCP is expressed in the human heart and kidney. Immunoreactive Ucn III was detected by RIA in the human heart (0.74-1.15 pmol/g wet weight, mean +/- SEM; n = 4) and kidney (1.21 +/- 0.30 pmol/g wet weight), which were obtained at autopsy. These levels were comparable to the levels in pituitary (2.72 +/- 0.13 pmol/g wet weight; n = 3) and brain tissues ( approximately 1-2 pmol/g wet weight). Furthermore, immunoreactive Ucn III was present in human plasma (51.8 +/- 16.0 pmol/liter; n = 5) and urine (266 +/- 20 pmol/liter; n = 5) obtained from healthy subjects. Reverse-phase HPLC showed a broad peak of immunoreactive Ucn III eluting in the position of synthetic Ucn III in the heart, kidney, and hypothalamus. Material eluting in the position of SCP was also found in the HPLC analysis of these tissue extracts. Immunocytochemistry showed positive staining of Ucn III in the myocardium and the renal tubules, particularly distal tubules. RT-PCR showed expression of Ucn III mRNA in the brain, pituitary, heart, and kidney. The present study has shown expression of Ucn III/SCP in the human heart and kidney as well as brain and pituitary tissues and its presence in plasma and urine. Ucn III/SCP may therefore regulate the cardiac and renal function as a local factor and a circulating hormone.