Mebamamide C, a deoxy analogue of mebamamides in Bryopsis marine green algae and Elysia sacoglossan mollusks.

Kahalalides, originally isolated from the sacoglossan mollusk Elysia rufescens, have been found in various Elysia and Bryopsis species, with over 20 variants identified to date. These compounds are biosynthesized by Candidatus Endobryopsis kahalalidefaciens within Bryopsis species. In this study, we report the isolation and structural determination of a new cyclic depsipeptide, mebamamide C (1), from Bryopsis sp. The planar structure was determined by spectroscopic data analyses, and the absolute configurations were determined using Marfey's method and modified Mosher's method. Additionally, our study explores the chemical relationship between Bryopsis algae and Elysia mollusks. The individual chemical profiles of these marine organisms highlight a fascinating aspect of marine chemical ecology. The distinct, species-specific chemical profiles observed in Elysia species imply the possibility of a symbiotic relationship with the kahalalide-producing bacteria.

5, 6, 11-trideoxy tetrodotoxin attracts tiger puffer Takifugu rubripes.

Tetrodotoxin (TTX) is a potent neurotoxin that binds to voltage-gated sodium channels and blocks the passage of sodium ions. TTX is widely distributed in both terrestrial and marine organisms, and the toxic puffers are believed to accumulate TTX through the food chain. Although pufferfish was previously thought to be attracted by TTX, recent finding from electroolfactogram (EOG) studies have indicated that the olfactory epithelium of T. alboplumbeus responded to 5, 6, 11-trideoxyTTX (TDT), but not to TTX itself. In this study, we examined behavioral experiments for Takifugu rubripes to distinguish between TTX and TDT under static and flow-through conditions. Our data clearly suggested that T. rubripes juveniles were attracted to TDT, not TTX. Moreover, we determined that the minimum effective dose of TDT to attract the puffer was 1-2 nmol of TDT under static conditions and 50-60 nmol of TDT under flow-through conditions. Following the experiments under static conditions, numerous bite marks by the pufferfish were found solely on the agarose gel infused with TDT. Based on these finding, we hypothesize that the pufferfish are attracted to TDT derived from prey, leading them effectively become toxic.

Evaluation of cortical bone remodeling in canines treated with daily and weekly administrations of teriparatide by establishing AI-driven morphometric analyses and GIS-based spatial mapping.

Larger animal models with a well-developed Haversian system, as observed in humans, are ideal to analyze cortical bone remodeling in pharmacological studies of anti-osteoporosis drugs, although they have some limitations in controlling individual variability in size, weight, age, and number. This study aimed to morphometrically analyze cortical bone remodeling focusing on Haversian canals in dogs using four regimens of TPTD with daily and weekly administrations at lower and higher weekly doses (4.9 µg/kg/week and 19.8 µg/kg/week, respectively) for 9 months. A micro-computed tomography-based analysis showed no significant differences among regimen groups. By establishing artificial intelligence (AI)-driven morphometric analyses and geographical information system (GIS)-based spatial mapping of Haversian canals that does not require confocal microscopy but is possible with more commonly used wide field microscopes, we successfully observed significant morphometric distinctions among regimens applied even in dogs. Our analytical results suggested that the daily higher regimen specifically increased the number of eroded pores creating spaces between existing canals, thus stimulating cortical bone remodeling.

Structure Determination of Kahalalide Analogues Based on Metagenomic Analysis of a Bryopsis sp. Marine Green Alga.

Two kahalalide analogues were isolated from a Bryopsis sp. marine green alga. Even though our initial structure determination of the peptides by NMR and MS identified them as kahalalide Z1 (KZ1; 3) and Z2 (KZ2; 4), the absolute configuration of the Thr residues by Marfey's analysis was different from those found in kahalalide F (KF), 3, and 4. To ascertain the absolute configuration of the amino acid residues genetically, we conducted a metagenomic analysis for symbiotic bacteria in the alga, leading to the biosynthetic gene cluster (BGC) responsible for producing the kahalalides named kahalalides Z3 (KZ3; 1) and Z4 (KZ4; 2). The identification of amino acid residues based on the A-domain suggested these peptides possess the amino acid sequence d-allo-Thr-l-Val-l-Val-d-Val residues at the N-terminus, instead of the d-Val-l-Thr-l-Val-d-Val residues found in KF, 3, and 4. The N-terminal amino acid sequence including absolute configuration was unambiguously determined by a comparison of LCMS data of synthetic tetrapeptides and the hydrolysates derived from 1 and 2. This structural difference is caused by swapping the substrate specificities of the first two A-domains.

Enigmazole Phosphomacrolides from the Marine Sponge Cinachyrella enigmatica.

Enigmazole B (1) and four new analogues, cis-enigmazole B (2), dehydroenigmazole B (3), enigmimide B (4), and enigmimide A (5), were isolated from the marine sponge Cinachyrella enigmatica. Their planar structures were elucidated by detailed NMR and MS data analyses, which established 1-3 to be oxazole-substituted 18-membered phosphomacrolides, while 4 and 5 were oxazole ring-opened congeners. The relative and absolute configurations in 1 were determined by a combination of chemical transformations and spectroscopic analyses. Photooxidation of the oxazole moiety in 1 gave enigmimide B (4), thus establishing that 4 has the same absolute configuration of 1. Enigmazole B (1) along with analogues 2 and 3 showed cytotoxicity against murine IC-2 mast cells with IC50 values of 3.6-7.0 µM. The enigmimides (4 and 5) and dephosphoenigmazoles did not show cytotoxicity (IC50 > 10 µM), implying that both the oxazole moiety and the phosphate group are necessary for the cytotoxicity of the enigmazole class macrolides.

Effect of HER2-targeted therapy on PDX and PDX-derived organoids generated from HER2-positive salivary duct carcinoma.

BACKGROUND: We previously established a patient-derived xenograft (PDX) model, patient-derived organoids (PDOs), and PDX-derived organoids (PDXOs) for salivary duct carcinoma (SDC). Using these models, this study examined the therapeutic effect of human epidermal growth factor receptor 2 (HER2) blockade on HER2-positive SDC. METHODS: The therapeutic effect of lapatinib was assessed in SDC PDXOs with regards to cell growth, receptor/downstream signaling molecule expression, phosphorylation levels, and apoptosis. Effect of lapatinib treatment was evaluated in vivo in SDC PDX mice. RESULTS: The siRNA knockdown of HER2 and lapatinib suppressed cell proliferation in SDC PDXOs. Lapatinib inhibited the phosphorylation of HER2 and its downstream targets, and induced apoptosis in SDC PDXOs. Lapatinib also significantly reduced tumor volumes compared with that of the control in SDC PDX mice. CONCLUSION: For the first time, we demonstrated the efficacy of anti-HER2 therapy in HER2-positive SDC using preclinical models of SDC PDX and PDXO.

Establishment of experimental salivary gland cancer models using organoid culture and patient-derived xenografting.

PURPOSE: Depending on its histological subtype, salivary gland carcinoma (SGC) may have a poor prognosis. Due to the scarcity of preclinical experimental models, its molecular biology has so far remained largely unknown, hampering the development of new treatment modalities for patients with these malignancies. The aim of this study was to generate experimental human SGC models of multiple histological subtypes using patient-derived xenograft (PDX) and organoid culture techniques. METHODS: Tumor specimens from surgically resected SGCs were processed for the preparation of PDXs and patient-derived organoids (PDOs). Specimens from SGC PDXs were also processed for PDX-derived organoid (PDXO) generation. In vivo tumorigenicity was assessed using orthotopic transplantation of SGC organoids. The pathological characteristics of each model were compared to those of the original tumors using immunohistochemistry. RNA-seq was used to analyze the genetic traits of our models. RESULTS: Three series of PDOs, PDXs and PDXOs of salivary duct carcinomas, one series of PDOs, PDXs and PDXOs of mucoepidermoid carcinomas and PDXs of myoepithelial carcinomas were successfully generated. We found that PDXs and orthotopic transplants from PDOs/PDXOs showed similar histological features as the original tumors. Our models also retained their genetic traits, i.e., transcription profiles, genomic variants and fusion genes of the corresponding histological subtypes. CONCLUSION: We report the generation of SGC PDOs, PDXs and PDXOs of multiple histological subtypes, recapitulating the histological and genetical characteristics of the original tumors. These experimental SGC models may serve as a useful resource for the development of novel therapeutic strategies and for investigating the molecular mechanisms underlying the development of these malignancies.

Partial Substitution of Glucose with Xylitol Prolongs Survival and Suppresses Cell Proliferation and Glycolysis of Mice Bearing Orthotopic Xenograft of Oral Cancer.

Many types of cancer have metabolic alterations with increased glycolysis. Identification of alternative sweeteners that do not fuel cancer is a novel approach to cancer control. The present study aimed to investigate the effects of xylitol on tumor growth and survival of mice bearing orthotopic xenograft of tongue cancers. The results showed that partial substitution of glucose with xylitol (glucose 0.35 g plus xylitol 2.06 g/kg body weight) non-significantly reduced tumor volume, and significantly prolonged the median survival time from 19 days in the control to 30.5 days in the xylitol group. Immunohistochemical data of the tongue tissue shows significantly lower intense-to-mild staining ratios of the proliferation marker Ki-67 in the xylitol than those of the control group (p = 0.04). Furthermore, the xylitol substitution significantly reduced the expression of the rate-limiting glycolytic enzyme, phosphofructokinase-1 (PFK-1) (p = 0.03), and showed a non-significant inhibition of PFK activity. In summary, partial substitution of glucose with xylitol at the equivalent dose to human household use of 10 g/day slows down tumor proliferation and prolongs survival of mice bearing an orthotopic oral cancer xenograft, possibly through glycolytic inhibition, with minimal adverse events. The insight warrants clinical studies to confirm xylitol as a candidate sweetener in food products for cancer survivors.

Single-cell metabolite detection and genomics reveals uncultivated talented producer.

The production of bioactive metabolites is increasingly recognized as an important function of host-associated bacteria. An example is defensive symbiosis that might account for much of the chemical richness of marine invertebrates including sponges (Porifera), 1 of the oldest metazoans. However, most bacterial members of sponge microbiomes have not been cultivated or sequenced, and therefore, remain unrecognized. Unequivocally linking metabolic functions to a cellular source in sponge microbiomes is, therefore, a challenge. Here, we report an analysis pipeline of microfluidic encapsulation, Raman microscopy, and integrated digital genomics (MERMAID) for an efficient identification of uncultivated producers. We applied this method to the chemically rich bacteriosponge (sponge that hosts a rich bacterial community) Theonella swinhoei, previously shown to contain 'Entotheonella' symbionts that produce most of the bioactive substances isolated from the sponge. As an exception, the antifungal aurantosides had remained unassigned to a source. Raman-guided single-bacterial analysis and sequencing revealed a cryptic, distinct multiproducer, 'Candidatus Poriflexus aureus' from a new Chloroflexi lineage as the aurantoside producer. Its exceptionally large genome contains numerous biosynthetic loci and suggested an even higher chemical richness of this sponge than previously appreciated. This study highlights the importance of complementary technologies to uncover microbiome functions, reveals remarkable parallels between distantly related symbionts of the same host, and adds functional support for diverse chemically prolific lineages being present in microbial dark matter.

A risk factor for newly diagnosed secondary cancer in patients with early-stage laryngeal, oropharyngeal, or hypopharyngeal cancer: sub-analysis of a prospective observation study.

BACKGROUND: We previously identified hypopharyngeal cancer as an independent risk factor for the incidence of newly diagnosed secondary cancers after the treatment of early-stage laryngeal, oropharyngeal, and hypopharyngeal cancers. We subsequently used a different patient cohort to validate the usefulness of this factor during the follow-up period in these patients. METHODS: Patients who underwent transoral surgery (TOS) as a definitive treatment between April 1, 2016, and September 30, 2020, were included. The incidence of secondary cancer was evaluated in hypopharyngeal and other cancers. Overall survival (OS), recurrence-free survival (RFS), and disease-free survival (DFS) outcomes were evaluated. Statistical analyses based on the risk factors were also performed. RESULTS: Incidence of new secondary cancer was 30% in hypopharyngeal cancer patients as compared to 11% in other cancer patients, and the risk was 3.60-fold (95% confidence interval 1.07-12.10) higher after definitive treatment for initial head and neck cancers. The 3-year OS, RFS, and DFS rates were 98%, 86%, and 67%, respectively. CONCLUSIONS: Among patients with early-stage laryngeal, oropharyngeal, and hypopharyngeal squamous cell carcinoma, who were initially treated with TOS, hypopharyngeal cancer patients had a higher risk of newly diagnosed secondary cancers as observed during the follow-up period.

FosL1 Regulates Regional Metastasis of Head and Neck Squamous Cell Carcinoma by Promoting Cell Migration, Invasion, and Proliferation.

BACKGROUND/AIM: We evaluated the impact of FosL1, a member of the activated protein-1 family, on the pathways leading to regional metastasis of head and neck squamous cell carcinoma (HNSCC). MATERIALS AND METHODS: We examined the influence of small interfering RNA (siRNA) and short heparin RNA (shRNA) mediated knockdown of FosL1 on cell migration, invasion, and proliferation in vitro as well as on regional metastasis in vivo. The prognostic significance of FosL1 was also analyzed using the Kaplan- Meier plotter using data from an HNSCC patient database. RESULTS: Down-regulation of FosL1 inhibited cell migration, invasion, and proliferation in vitro, decreased the incidence of regional metastases, and prolonged the survival of mice in vivo. We also determined that HNSCC patients with higher expression levels of FosL1 had a significantly shorter survival time than those with low expression of FosL1. CONCLUSION: FosL1 plays a crucial role in promoting cell migration, invasion, and proliferation in HNSCC.

Validation of the risk factors for primary control of early T-stage laryngeal, oropharyngeal, and hypopharyngeal squamous cell carcinoma by transoral surgery: a prospective observational study.

BACKGROUND: We had previously identified the following risk factors for insufficient control of early T-stage head and neck cancer by transoral surgery (TOS): (1) tumor thickness > 7 mm on enhanced computed tomography (CT), and (2) poor differentiation in pathological examination. We subsequently used a different patient cohort to validate the usefulness of these factors in determining the need for adaptation of TOS. STUDY SETTING: A prospective observational study METHODS: Patients who received TOS as a definitive treatment between April 1, 2016 and September 30, 2020 were included. Primary control rates (by single TOS and TOS alone) in relation to the above-mentioned risk factors were calculated. Overall (O), recurrence-free (RF), and disease-free (DF) survival (S) outcomes were evaluated. A combination analysis based on the number of risk factors was also performed. RESULTS: Patients with tumor thickness > 7 mm had a 2.88-fold [95% confidence interval (CI) 1.01-8.51] higher risk of incomplete primary resection by single TOS, while patients who showed poor differentiation on pathological assessments had a 13.14-fold (95% CI 3.66-47.14) higher risk of insufficient primary control by TOS alone. The 3 year OS, RFS, and DFS rates were 99%, 83%, and 63%, respectively. Patients with both risk factors had a 93.00-fold (95% CI 4.99-1732.00) higher risk of incomplete primary control by TOS alone. CONCLUSIONS: Among patients with early-stage laryngeal, oropharyngeal, and hypopharyngeal squamous cell carcinoma, primary control by TOS alone may not be achieved in patients with both risk factors, that is, tumor thickness > 7 mm as measured by enhanced CT and poor differentiation on pathological examination.

Establishment of PDX-derived salivary adenoid cystic carcinoma cell lines using organoid culture method.

To generate a reliable preclinical model system exhibiting the molecular features of salivary adenoid cystic carcinoma (ACC) whose biology is still unclear due to the paucity of stable cell cultures. To develop new in vitro and in vivo models of ACC, the techniques of organoid culture and patient-derived tumor xenograft (PDX), which have attracted attention in other malignancies in recent years, were applied. Tumor specimens from surgically resected salivary ACC were proceeded for the preparation of PDX and organoid culture. The orthotopic transplantation of patient-derived or PDX-derived organoids was demonstrated into submandibular glands of NSG mice and those histology was evaluated. PDX-derived organoid cells were evaluated for the presence of MYB-mediated fusion genes and proceeded for in vitro drug sensitivity assay. Human ACC-derived organoids were successfully generated in three-dimensional culture and confirmed the ability of these cells to form tumors by orthotopic injection. Short-term organoid cell cultures from two individual ACC PDX tumors were also established that maintain the characteristic MYBL1 translocation and histological features of the original parent and PDX tumors. Finally, the establishment of drug sensitivity tests on these short-term cultured cells was confirmed using three different agents. This is the first to report an approach for the generation of human ACC-derived organoids as in vitro and in vivo cancer models, providing insights into understanding of the ACC biology and creating personalized therapy design for patients with ACC.

The incidence of newly diagnosed secondary cancer; sub-analysis the prospective study of the second-look procedure for transoral surgery in patients with T1 and T2 head and neck cancer.

BACKGROUND: Our prospective study of patients with early T-stage head and neck cancer indicated a high incidence of newly diagnosed secondary malignancies during the follow-up period. We aimed to determine the incidence rate and risk factors of secondary malignancies in early-stage head and neck cancer patients. METHODS: We sub-analyzed the patient data of a previous study focusing on secondary cancer incidence. The endpoints were statistical analyses of risk factors and survival and incidence rates. RESULTS: The incidence rate of secondary cancer was 37%, the crude incidence of second primary cancers was 10.6 per 100 person-years, and the 5 year secondary cancer-free survival rate was 63%. The hypopharynx as the primary site was an independent significant predictive factor (odds ratio 3.96, 95% confidence interval 1.07-14.6, p = 0.039). CONCLUSIONS: Early stages of laryngeal, oropharyngeal, and hypopharyngeal cancer had a risk of secondary cancer, especially hypopharyngeal cancer. Attention to the secondary cancer has to be paid during the follow-up period after controlling the early-stage disease. These findings highlight the need for awareness of the incidence of secondary cancer in cases of early-stage primary head and neck cancer.

Heptavalinamide A, an Extensively N-Methylated Linear Nonapeptide from a Cyanobacterium Symploca sp. and Development of a Highly Sensitive Analysis of N,N-Dimethylvaline by LCMS.

An extensively N-methylated linear nonapeptide heptavalinamide A (1) was isolated from the marine cyanobacterium Symploca sp. collected at Kabira Reef of Ishigaki Island, Okinawa. The amino acid sequence of 1 was assigned by interpretation of 2D NMR and MS/MS data. The absolute configurations of the constituent amino acids were determined by the application of Marfey's method. A method to assign the configuration of N,N-dimethylvaline by LCMS is discussed.

Metachromins X and Y from a marine sponge Spongia sp. and their effects on cell cycle progression.

New sesquiterpene quinones, metachromins X (1) and Y (2), together with the known metachromins C (3), J (4), and T (5), were isolated as inhibitors of cell cycle progression in the HeLa/Fucci2 cells. The structure of 1 was assigned by spectroscopic data and confirmed by a total synthesis. The planar structure of 2 was determined by interpretation of spectroscopic data, whereas its absolute configuration was analyzed by a combination of chiral HPLC and CD spectroscopy. Metachromins X (1) and C (3) arrested the cell cycle progression of HeLa/Fucci2 cells at S/G2/M phase.

The Revised Structure of the Cyclic Octapeptide Surugamide A.

Surugamides are a group of non-ribosomal peptides isolated from marine-derived Streptomyces. Surugamide A (1) and its closely related derivatives, surugamides B-E (2-5), are D-amino acid containing cyclic octapeptides with cathepsin B inhibitory activity. The D-isoleucine (Ile), the nonproteinogenic amino acid residue embedded in 1, is less common in natural peptides because a rare Cß-epimerization is required for its biosynthesis. Taking advantage of the synthetic route of 2 previously established by our group, we synthesized the cyclic octapeptide 1 containing D-Ile by solid phase peptide synthesis. The structure of 1 actually contains D-allo-Ile in place of D-Ile, which was corroborated by chemical syntheses and chromatographic comparisons.

SurE is a trans-acting thioesterase cyclizing two distinct non-ribosomal peptides.

SurE is a new, stand-alone thioesterase (TE) offloading the non-ribosomal peptide (NRP) assembly line found in surugamide biosynthesis. It is homologous to penicillin binding protein (PBP) and capable of cyclizing two structurally unrelated substrates derived from two different NRP assembly lines, highlighting the broad substrate tolerance of the SurE offloading cyclase.

Colony-wise Analysis of a Theonella swinhoei Marine Sponge with a Yellow Interior Permitted the Isolation of Theonellamide I.

There are several examples of marine organisms whose metabolic profiles differ among conspecifics inhabiting the same region. We have analyzed the metabolic profile of each colony of a Theonella swinhoei marine sponge with a yellow interior and noticed the patchy distribution of one metabolite. This compound was isolated and its structure was studied by a combination of spectrometric analyses and chemical degradation, showing it to be a congener in the theonellamide class of bicyclic peptides. Theonellamides had previously been isolated by us only from T. swinhoei with a white interior and not from those with a yellow interior.

Diastereoselective Total Synthesis and Structural Confirmation of Surugamide F.

Surugamide F is a linear decapeptide (1) isolated along with the cyclic octapeptides surugamides A-E (2-6), from a marine-derived Streptomyces species. The linear peptide 1 is produced by two nonribosomal peptide synthetases (NRPSs) encoded in adjacent open reading frames, which are further flanked by an additional pair of NRPS genes responsible for the biosyntheses of the cyclic peptides 2-6. While the cyclic peptides 2-6 were identified to be cathepsin B inhibitors, the biological activity of the new metabolite 1 still remained unclear. In order to elucidate its unique biosynthetic pathway and biological activity in detail, we planned to develop an efficient synthetic route toward 1. Here we report the diastereoselective total synthesis of 1, utilizing 9-fluorenylmethyloxycarbonyl (Fmoc)-based solid-phase peptide synthesis. During this study, we found that the structural correction of 1 was required, due to the mislabeling of the commercially obtained 3-amino-2-methylpropionic acid, and the true structure of 1 was corroborated by the chemical synthesis and chromatographic comparison.