Aberrant Glycosylation in Pancreatic Ductal Adenocarcinoma 3D Organoids Is Mediated by KRAS Mutations.

Aberrant glycosylation in tumor cells is a hallmark during carcinogenesis. KRAS gene mutations are the most well-known oncogenic abnormalities but their association with glycan alterations in pancreatic ductal adenocarcinoma (PDAC) is largely unknown. We employed patient-derived 3D organoids to culture pure live PDAC cells, excluding contamination by fibroblasts and immune cells, to gasp the comprehensive cancer cell surface glycan expression profile using lectin microarray and transcriptomic analyses. Surgical specimens from 24 PDAC patients were digested and embedded into a 3D culture system. Surface-bound glycans of 3D organoids were analyzed by high-density, 96-lectin microarrays. KRAS mutation status and expression of various glycosyltransferases were analyzed by RNA-seq. We successfully established 16 3D organoids: 14 PDAC, 1 intraductal papillary mucinous neoplasm (IPMN), and 1 normal pancreatic duct. KRAS was mutated in 13 (7 G12V, 5 G12D, 1 Q61L) and wild in 3 organoids (1 normal duct, 1 IPMN, 1 PDAC). Lectin reactivity of AAL (Aleuria aurantia) and AOL (Aspergillus oryzae) with binding activity to α1-3 fucose was higher in organoids with KRAS mutants than those with KRAS wild-type. FUT6 (α1-3fucosyltransferase 6) and FUT3 (α1-3/4 fucosyltransferase 3) expression was also higher in KRAS mutants than wild-type. Meanwhile, mannose-binding lectin (rRSL [Ralstonia solanacearum] and rBC2LA [Burkholderia cenocepacia]) signals were higher while those of galactose-binding lectins (rGal3C and rCGL2) were lower in the KRAS mutants. We demonstrated here that PDAC 3D-cultured organoids with KRAS mutations were dominantly covered in increased fucosylated glycans, pointing towards novel treatment targets and/or tumor markers.

Triple modal treatment comprising with proton beam radiation, hyperthermia, and gemcitabine/nab-paclitaxel for locally advanced pancreatic cancer: a phase I/II study protocol (TT-LAP trial).

BACKGROUND: Locally advanced pancreatic ductal adenocarcinoma (PDAC), accounting for about 30% of PDAC patients, is difficult to cure by radical resection or systemic chemotherapy alone. A multidisciplinary strategy is required and our TT-LAP trial aims to evaluate whether triple-modal treatment with proton beam therapy (PBT), hyperthermia, and gemcitabine plus nab-paclitaxel is a safe and synergistically effective treatment for patients with locally advanced PDAC. METHODS: This trial is an interventional, open-label, non-randomized, single-center, single-arm phase I/II clinical trial organized and sponsored by the University of Tsukuba. Eligible patients who are diagnosed with locally advanced pancreatic cancer, including both borderline resectable (BR) and unresectable locally advanced (UR-LA) patients, and selected according to the inclusion and exclusion criteria will receive triple-modal treatment consisting of chemotherapy, hyperthermia, and proton beam radiation. Treatment induction will include 2 cycles of chemotherapy (gemcitabine plus nab-paclitaxel), proton beam therapy, and 6 total sessions of hyperthermia therapy. The initial 5 patients will move to phase II after adverse events are verified by a monitoring committee and safety is ensured. The primary endpoint is 2-year survival rate while secondary endpoints include adverse event rate, treatment completion rate, response rate, progression-free survival, overall survival, resection rate, pathologic response rate, and R0 (no pathologic cancer remnants) rate. The target sample size is set at 30 cases. DISCUSSION: The TT-LAP trial is the first to evaluate the safety and effectiveness (phases1/2) of triple-modal treatment comprised of proton beam therapy, hyperthermia, and gemcitabine/nab-paclitaxel for locally advanced pancreatic cancer. ETHICS AND DISSEMINATION: This protocol was approved by the Tsukuba University Clinical Research Review Board (reference number TCRB22-007). Results will be analyzed after study recruitment and follow-up are completed. Results will be presented at international meetings of interest in pancreatic cancer plus gastrointestinal, hepatobiliary, and pancreatic surgeries and published in peer-reviewed journals. TRIAL REGISTRATION: Japan Registry of Clinical Trials, jRCTs031220160. Registered 24 th June 2022, https://jrct.niph.go.jp/en-latest-detail/jRCTs031220160 .

Lectin-based phototherapy targeting cell surface glycans for pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is resistant to current treatments but lectin-based therapy targeting cell surface glycans could be a promising new horizon. Here, we report a novel lectin-based phototherapy (Lec-PT) that combines the PDAC targeting ability of rBC2LCN lectin to a photoabsorber, IRDye700DX (rBC2-IR700), resulting in a novel and highly specific near-infrared, light-activated, anti-PDAC therapy. Lec-PT cytotoxicity was first verified in vitro with a human PDAC cell line, Capan-1, indicating that rBC2-IR700 is only cytotoxic upon cellular binding and exposure to near-infrared light. The therapeutic efficacy of Lec-PT was subsequently verified in vivo using cell lines and patient-derived, subcutaneous xenografting into nude mice. Significant accumulation of rBC2-IR700 occurs as early as 2 hours postintravenous administration while cytotoxicity is only achieved upon exposure to near-infrared light. Repeated treatments further slowed tumor growth. Lec-PT was also assessed for off-target toxicity in the orthotopic xenograft model. Shielding of intraperitoneal organs from near-infrared light minimized off-target toxicity. Using readily available components, Lec-PT specifically targeted pancreatic cancer with high reproducibility and on-target, inducible toxicity. Rapid clinical development of this method is promising as a new modality for treatment of pancreatic cancer.

Survival impact on triple-modal strategy comprising hyperthermia, external radiation, and chemotherapy for unresectable locally advanced (UR-LA) pancreatic ductal adenocarcinoma.

BACKGROUND: Present treatment strategy for unresectable locally advanced (UR-LA) pancreatic ductal adenocarcinoma (PDAC) patients is controversial. Hence, a triple-modal therapy, which is a multidisciplinary strategy, was designed for patients with UR-LA PDAC by adding hyperthermia to conventional chemoradiotherapy at our institution. In this study we aimed to evaluate the effectiveness of this strategy. METHODS: Data of 21 UR-LA PDAC patients who underwent the triple-modal treatment were retrospectively analyzed for evaluating the safety and oncological effect of the treatment. The treatment schedule included, five concurrent infusions of gemcitabine (800 mg/m2) followed by hyperthermia (1 h) and X-ray (2 Gy) or proton beam radiation (2.7 Gy) on days 1, 8, 15, 29, and 36. Additional radiotherapies applied a total dose of 50 Gy/25 fr for X-ray radiation or 67.5 Gy/25 fr for proton beam radiation. RESULTS: Median overall survival (OS) was 23.6 months. Conversion surgery was performed in 5 patients (23.8%), and a R0 margin could be achieved in 4 of them; however, their median OS (16.3 months) tended to be shorter than that of the patients who did not undergo resection (23.6 months, p = 0.562). Further, the median OS of patients who underwent proton beam radiation (28.0 months) was significantly longer than that of patients who underwent X-ray radiation (13.9 months, p = 0.045). Most adverse events were manageable, except for one grade 3 gastric ulcer. The median tumor size and marker reduction rates were -17% and -91%, respectively. The tumor responses were partial response, stable disease, and progressive disease in 3, 15, and 3 patients, respectively. CONCLUSION: Triple-modal strategy, especially when combined with proton beam radiation, is feasible and results in favorable survival outcomes in patients with UR-LA PDAC.

Intussusception induced by gastrointestinal metastasis of malignant melanoma: A case report.

INTRODUCTION: Malignant melanoma sometimes metastasizes to small intestine, and could cause various clinical symptoms, including intussusception. Among the acute abdomen cohort in Japan, it is quite rare to encounter this entity. PRESENTATION OF CASE: A 68-year-old male patient was admitted to our hospital with chief complaints of abdominal pain and vomiting.　He underwent tumor resection for malignant melanoma of the primary lesion at left foot base, local recurrence and brain metastasis during the last five years. At admission, abdominal X-ray demonstrated small bowel obstruction. An ileus tube was inserted, and contrast media enema study showed crab-like shadow defect was observed in the advanced part. Enhanced computed tomography showed intussusception in the proximal jejunum caused by a tumor of 5 cm in diameter in the advanced part. No other intestinal lesion was found. Diagnosis of intussusception caused by solitary metastasis of malignant melanoma was made. Laparoscopic partial resection of the small intestine was performed. Postoperative course was uneventful, and patient was followed in outpatient clinic without further treatment with any recurrence of disease for one years. DISCUSSION: Malignant melanoma tends to metastases to the small intestine simultaneously and multiply. It bothers surgeons to decide range of small intestinal resection at emergency surgery. In the present study, preoperative examination allowed the adequate range of intestinal resection including location and number of metastases before operation. CONCLUSION: When an acute abdomen caused by intestinal metastasis of malignant melanoma was consulted, surgeon should make effort to identify location and number of metastatic lesion, preoperatively.

Exploring optimal examination to detect occult anastomotic leakage after rectal resection in patients with diverting stoma.

BACKGROUND: When considering "early stoma closure", both standardized inclusion/exclusion criteria and standardized methods to assess anastomosis are necessary to reduce the risk of occult anastomotic leakage (AL). However, in the immediate postoperative period, neither have the incidence and risk factors of occult AL in patients with diverting stoma (DS) been clarified nor have methods to assess anastomosis been standardized. The aim of this study was to elucidate the incidence and risk factors of occult AL in patients who had undergone rectal resection with DS and to evaluate the significance of computed tomography (CT) following water-soluble contrast enema (CE) to detect occult anastomotic leakage. METHODS: This was a single institutional prospective observational study of patients who had undergone rectal resection with the selective use of DS between May and October 2019. Fifteen patients had undergone CE and CT to assess for AL on postoperative day (POD) 7, and CT was performed just after CE. Univariate analysis was performed to assess the relationship between preoperative variables and the incidence of occult AL on POD 7. RESULTS: The incidence of occult AL on postoperative day 7 was 6 of 15 (40%). Hand-sewn anastomosis, compared with stapled anastomosis, was a significant risk factor. Five more cases with occult AL that could not be detected with CE could be detected on CT following CE; CE alone had a 33% false-negative radiological result rate. CONCLUSIONS: Hand-sewn anastomosis appeared to be a risk factor for occult AL, and CE alone had a high false-negative radiological result rate. When considering the introduction of early stoma closure, stapled anastomosis and CT following CE could be an appropriate inclusion criterion and preoperative examination, respectively.

Therapeutic effects of an orally administered edible seaweed-derived polysaccharide preparation, ascophyllan HS, on a Streptococcus pneumoniae infection mouse model.

Ascophyllan HS is a commercially available preparation of the edible brown alga Ascophyllum nodosum containing ascophyllan, a sulfated polysaccharide with diverse beneficial biological activities. In this study, the effects of ascophyllan HS were evaluated in a severe intranasal Streptococcus pneumoniae infection mouse model. The control untreated mice started to die on day 7 and 80% had died by day 14 post-infection. Continuous oral administration of ascophyllan HS before and after bacterial infection resulted in a remarkable increase in survival rate, with 90% of the low (167 mg/kg body weight/day) and 100% of the high (500 mg/kg body weight/day) dose ascophyllan HS-treated mice surviving at day 14 post-infection. Histopathological observation of the lungs of the infected mice revealed the induction of typical pneumonia features in the alveolar spaces of the untreated control mice, such as extensive infiltration of inflammatory cells, edema, and fibrin deposition. In contrast, notable levels of lung injuries or alterations were not observed in the ascophyllan HS-treated mice, and only a minor lesion was observed in one mouse. Furthermore, bacterial burdens in the lungs were significantly reduced in the ascophyllan HS-treated mice as compared to the control mice at day 4 post-infection. Significantly higher levels of IL-12 were detected in the serum of ascophyllan HS-treated mice than that of control mice measured at the end of the infection experiment (day 14). These results suggest that orally administered ascophyllan HS exerts a therapeutic effect on S. pneumoniae infection by activating the host defense systems. This is the first report of the therapeutic effect of an orally administered seaweed polysaccharide preparation on S. pneumoniae infection. Our findings suggest that ascophyllan HS has the potential to be developed as nutraceuticals and pharmaceuticals applicable for humans as well as a safe and promising therapeutic agent against S. pneumoniae infection.

Increase in anti-inflammatory activities of radical-degraded porphyrans isolated from discolored nori (Pyropia yezoensis).

The anti-inflammatory properties of porphyrans (D1-D4) obtained from four discolored nori (Pyropia yezoensis) with different growth backgrounds were studied to examine possible variations in their bioactivities. Elution profiles of the porphyrans on Sepharose 4B indicated that D2-porphyran had relatively lower-molecular-size porphyrans than the other porphyrans. Inhibitory activities of the four porphyrans against nitric oxide (NO) and tumor necrosis factor-α (TNF-α) secretion by lipopolysaccharide (LPS)-stimulated RAW264.7 cells were different, whereas no significant differences were observed in the sulfate and anhydrogalactose levels. D2-porphyran showed the highest inhibitory activity against NO and TNF-α secretion by LPS-stimulated RAW264.7 cells, whereas D3- and D4-porphyrans had almost no activity. All porphyrans were efficiently degraded by free radical generated with ascorbate and hydrogen peroxide. The free-radical degradation resulted in a significant increase in the inhibitory activities of the four porphyrans against NO and TNF-α secretion, with varying rates depending on the porphyrans. The ability of D2-porphyran to suppress the receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastogenesis in RAW264.7 cells was also significantly enhanced after degradation. Our results suggest that molecular size is an important factor affecting the anti-inflammatory activity of porphyrans, and radical degradation might be a promising procedure to obtain active low-molecular-size porphyrans.

Inhibitory effect of sulphated polysaccharide porphyran (isolated from Porphyra yezoensis) on RANKL-induced differentiation of RAW264.7 cells into osteoclasts.

Safe and efficient therapeutic agents for bone diseases are required in natural sources. We previously found that edible seaweed-derived polysaccharide porphyran exhibited anti-inflammatory effects through the down regulation of nuclear factor-κB. The aim of this study was to investigate the availability of porphyran as a therapeutic agent for bone diseases. The effects of porphyran on receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastogenesis in RAW264.7 cells were examined. Porphyran suppressed RANKL-induced osteoclast formation in a concentration-dependent manner (6.25-50 µg/ml) without any cytotoxic effects. Furthermore, real-time polymerase chain reaction analyses indicated that porphyran at 50 µg/ml significantly attenuated the RANKL-induced increase in the mRNA levels of osteoclastogenesis-related marker genes such as nuclear factor of activated T cells, tartrate-resistant acid phosphatase, cathepsin K, and matrix metalloproteinase-9 in RAW264.7 cells. To our knowledge, this is the first report showing that edible-seaweed-derived polysaccharide porphyran can suppress RANKL-induced osteoclastogenesis. Our results suggest that porphyran can be used as a safe therapeutic agent to improve osteoclast-related pathological conditions.

Ginseng Berry Extract Attenuates Dextran Sodium Sulfate-Induced Acute and Chronic Colitis.

This study investigates the in vivo functions of ginseng berry extract (GB) as a therapy for dextran sodium sulfate (DSS)-induced colitis. C57BL/6 mice were given drinking water containing DSS (3%) for eight days to induce acute colitis. At the same time, the mice received an oral dose of GB (50 mg/kg) once daily. The GB-treated mice were less susceptible to the development of acute colitis than were control mice treated with saline, as determined by weight loss, disease activity, and colon histology. The administration of GB to DSS-treated mice also reduced the numbers and inhibited the activation of colon-infiltrating T cells, neutrophils, intestinal CD103(-)CD11c⁺ dendritic cells (cDCs), and macrophages. In addition, GB treatment promoted the migration of CD103⁺CD11c⁺ cDCs and expansion of Foxp3⁺ regulatory T cells in the colons of DSS-treated mice. Similarly, in the DSS-induced chronic colitis model, GB treatment improved the macroscopic and histological appearance of the colon wall when compared to untreated control mice, as indicated by longer colon length and lower histological scores. This is the first report to show that oral administration of GB suppresses immune activation and protects against experimentally induced colitis.

Cetuximab delivery and antitumor effects are enhanced by mild hyperthermia in a xenograft mouse model of pancreatic cancer.

Even with current promising antitumor antibodies, their antitumor effects on stroma-rich solid cancers have been insufficient. We used mild hyperthermia with the intent of improving drug delivery by breaking the stromal barrier. Here, we provide preclinical evidence of cetuximab + mild hyperthermia therapy. We used four in vivo pancreatic cancer xenograft mouse models with different stroma amounts (scarce, MIAPaCa-2; moderate, BxPC-3; and abundant, Capan-1 and Ope-xeno). Cetuximab (1 mg/kg) was given systemically, and the mouse leg tumors were concurrently heated using a water bath method for 30 min at three different temperatures, 25°C (control), 37°C (intra-abdominal organ level), or 41°C (mild hyperthermia) (n = 4, each group). The evaluated variables were the antitumor effects, represented by tumor volume, and in vivo cetuximab accumulation, indirectly quantified by the immunohistochemical fluorescence intensity value/cell using antibodies against human IgG Fc. At 25°C, the antitumor effects were sufficient, with a cetuximab accumulation value (florescence intensity/cell) of 1632, in the MIAPaCa-2 model, moderate (1063) in the BxPC-3 model, and negative in the Capan-1 and Ope-xeno models (760, 461). By applying 37°C or 41°C heat, antitumor effects were enhanced shown in decreased tumor volumes. These enhanced effects were accompanied by boosted cetuximab accumulation, which increased by 2.8-fold (2980, 3015) in the BxPC-3 model, 2.5- or 4.8-fold (1881, 3615) in the Capan-1 model, and 3.2- or 4.2-fold (1469, 1922) in the Ope-xeno model, respectively. Cetuximab was effective in treating even stroma-rich and k-ras mutant pancreatic cancer mouse models when the drug delivery was improved by combination with mild hyperthermia.

Antioxidant and anti-inflammatory activities of porphyran isolated from discolored nori (Porphyra yezoensis).

We found that discolored waste nori with no commercial value, contains much higher level of porphyran than normal nori that is a sheeted food stuff prepared from P. yezoensis used in sushi. Chemical analyses revealed that mean molecular mass of the porphyran prepared from discolored nori (dc-porphyran) was much lower than that of the porphyran from normal nori (n-porphyran). Dc-porphyran showed slightly greater scavenging activity toward superoxide anion and hydroxyl radical than n-porphyran. Dc-porphyran inhibited nitric oxide (NO) production in LPS-stimulated RAW264.7 cells through preventing the expression of inducible NO synthase, whereas no such activity was observed in n-porphyran. Since acid-hydrolyzed n-porphyran showed the inhibitory activity on NO production from LPS-stimulated RAW264.7 cells, the molecular size of porphyran was suggested to be a critical factor for the activity. Dc-porphyran was separated into 4 fractions (F1-F4) on DEAE-chromatography, and F1 showed the highest inhibitory effect on NO production from LPS-stimulated RAW264.7 cells. Our results indicate that discolored waste nori is useful as a source of porphyran with even better bioactivities than porphyran from normal nori.

Inhibitory effect of orally-administered sulfated polysaccharide ascophyllan isolated from ascophyllum nodosum on the growth of sarcoma-180 solid tumor in mice.

We evaluated the antitumor activity of crude extract and ascophyllan prepared from Ascophyllum nodosum in sarcoma-180 solid tumor-bearing mice with continuous intraperitoneal (i.p.) administration at a dose of 50 mg/kg body weight/day or oral administration at a dose of 500 mg/kg body weight/day. Ascophyllan and crude extract administered via the oral route showed greater antitumor effects than via i.p. route, and the tumor sizes in mice treated with ascopyllan and crude extract were reduced by a mean of 68.7±6.8% and 42.4±24.8% by the oral route, and 41.4±16.1% and 13.6±20.6% by i.p. route compared to control mice. Splenic natural killer cell activity in the mice treated with ascophyllan and crude extract by i.p. route was significantly enhanced, while only a slight increase of this activity was observed in orally-treated mice. Furthermore, increase in spleen weight of tumor-bearing mice was slightly suppressed by oral administration of ascophyllan, whereas i.p. administration resulted in further enlargement. Analysis of serum cytokines revealed that oral treatment with ascophyllan resulted in significant increase of tumor necrosis factor-α and interleukin-12 levels. Since ascophyllan showed no direct cytotoxic effect on sarcoma-180 cells, orally-administered ascophyllan is suggested to exhibit its antitumor activity through the activation of the host immune system.

Anti-inflammatory effect of essential oil and its constituents from fingered citron (Citrus medica L. var. sarcodactylis) through blocking JNK, ERK and NF-κB signaling pathways in LPS-activated RAW 264.7 cells.

We investigated the composition of essential oil from fingered citron (Citrus medica L. var. sarcodactylis) (FCEO) peels by GC-MS and its anti-inflammatory effects on lipopolysaccharide (LPS) - stimulated mouse macrophage (RAW 264.7) cells. Fifteen compounds, representing 98.97% of the essential oil, were tentatively identified; the main constituents were limonene (52.44%) and γ-terpinene (28.41%). FCEO significantly inhibited nitric oxide (NO) and prostaglandin E2 (PGE2) by suppressing the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, respectively. Additionally, FCEO suppressed the production of tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, and IL-6. FCEO attenuated LPS-induced nuclear factor-κB (NF-κB) activation via inhibition of inhibitor κB-α phosphorylation. Furthermore, FCEO blocked activation of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) but not that of p38 mitogen-activated protein kinase. These results indicate that FCEO inhibits LPS-stimulated inflammation by blocking the NF-κB, JNK, and ERK pathways in macrophages, and demonstrate that FCEO possesses anti-inflammatory properties.

Antioxidant properties of aqueous extracts from red tide plankton cultures.

The antioxidant properties of aqueous extracts from the dinophycean flagellates Gymnodinium impudicum and Alexandrium affine and the raphidophycean flagellate Chattonella ovata were examined. An electron spin resonance (ESR)-spin trapping method coupled with steady state kinetic analysis showed that all of the extracts directly scavenge superoxide, and that the superoxide scavenging potential of any of the extracts was comparable to that of L-ascorbic acid. As for hydroxyl radical scavenging, the Fenton reaction and the method of ultraviolet radiation to hydrogen peroxide were used as hydroxyl radical generation systems. All of extracts reduced the level of hydroxyl radicals in both of the systems, indicating that the extracts also directly scavenge hydroxyl radicals. Since the levels of phenolic compounds did not correlate with the antioxidant activities of the extracts, substances other than phenolic compounds also appeared to be attributable to the activities. It is of our interest that the scavenging activities of extract from G. impudicum against superoxide and hydroxyl radicals were increased by heat exposure at 100 degrees C and 200 degrees C respectively. Although the reason for the increased activities of the aqueous extract from G. impudicum is not clear, the heat-resistance of the extract from G. impudicum might make it a desirable antioxidant.

Production of reactive oxygen species (ROS) by devil stinger (Inimicus japonicus) during embryogenesis.

In aqua-cultural industry, the seed production of devil stinger, a valuable fish in Japan, has not succeeded yet due to the cryptogenic mass mortality. We found that survival rate of the larvae of devil stinger increased by the addition of green tea extract rich in catechin into rearing tank. Generation of reactive oxygen species (ROS) was detected in the embryo of devil stinger by chemiluminescence analysis under the normal growth conditions without addition of specific stimulants. Even in the unfertilized egg, certain level of ROS was detected. ROS were continuously detected during the development from fertilized egg to larva and tended to increase gradually. Observation of embryos and post-hatching larvae with hypersensitive photon-counting microscopy indicated that ROS were produced on the surface of embryo and the head region of larva especially peripheries of eyes. When the embryo proteins were analyzed by immunoblotting using antibody against the human neutrophil cytochrome b558 large subunit (gp91 phox), a main band of approximately 91 kDa was detected, suggesting the presence of NADPH oxidase-like ROS generating system in the embryo of devil stinger. After treatment with streptomycin and penicillin G for 1 day, the level of ROS production in larvae decreased with increase in the survival rate of larvae. Our results suggest that devil stinger has ROS generation system that is already activated at fairly early stage of development before the maturation of usual immune system.

Evaluation of the anti-Trichophyton activity of a prodigiosin analogue produced by gamma-proteobacterium, using stratum corneum epidermis of the Yucatan micropig.

Prodigiosins (PGs) are known to be a family of natural red pigments, characterized by a common pyrrolydipyrrolylmethane skeleton structure with a C-4 methoxy group, and some of these pigments have been isolated from some microorganisms. Members of the PG family have been reported to show several biological activities, such as immunosuppressive and cytotoxic activities. Recently, we discovered a bacterial strain (MS-02-063), from our microbial library, that produces large amounts of a PG analogue (PG-L-1). In this study, we examined the anti-Trichophyton activity of PG-L-1 (produced by strain MS-02-063) against clinically isolated Trichophyton spp., by a method using stratum corneum epidermis (SCE) of the Yucatan micropig, which is suitable for estimating the antifungal activity of drugs in vitro. In the National Committee for Clinical Laboratory Standards (NCCLS) method, PG-L-1 showed potent antifungal activity against nine clinically isolated strains of Trichophyton spp., although the minimum inhibitory concentration (MIC) values were slightly higher than those of bifonazole. In spite of the lower efficiency of PG-L-1 transfer into SCE from medium than that of bifonazole, PG-L-1 transferred into SCE showed more potent antifungal activity than bifonazole, at lower concentrations.