Distribution of internal medicine rotations among resident physicians in Japan: a nationwide, multicenter, cross-sectional study.

BACKGROUND: In Japan, postgraduate clinical training encompasses a 2-year residency program, including at least 24 weeks of internal medicine (IM) rotations. However, the fragmented structure of these rotations can compromise the training's quality and depth. For example, a resident might spend only a few weeks in cardiology before moving to endocrinology, without sufficient time to deepen their understanding or have clinical experience. This study examined current patterns and lengths of IM rotations within the Japanese postgraduate medical system. It scrutinized the piecemeal approach-whereby residents may engage in multiple short-term stints across various subspecialties without an overarching, integrated experience-and explored potential consequences for their clinical education. METHODS: This nationwide, multicenter, cross-sectional study used data from self-reported questionnaires completed by participants in the 2022 General Medicine In-Training Examination (GM-ITE). Data of 1,393 postgraduate year (PGY) one and two resident physicians who participated in the GM-ITE were included. We examined the IM rotation duration and number of IM subspecialties chosen by resident physicians during a 2-year rotation. RESULTS: Approximately half of the participants chose IM rotation periods of 32-40 weeks. A significant proportion of participants rotated in 5-7 internal medicine departments throughout the observation period. Notable variations in the distribution of rotations were observed, characterized by a common pattern where resident physicians typically spend 4 weeks in each department before moving to the next. This 4-week rotation is incrementally repeated across different subspecialties without a longer, continuous period in any single area. Notably, 39.7% of participants did not undertake general internal medicine rotations. These results suggest a narrowed exposure to medical conditions and patient care practices. CONCLUSIONS: Our study highlights the need to address the fragmented structure of IM rotations in Japan. We suggest that short, specialized learning periods may limit the opportunity to gain broad in-depth knowledge and practical experience. To improve the efficacy of postgraduate clinical education, we recommend fostering more sustained and comprehensive learning experiences.

Performance Comparison of ChatGPT-4 and Japanese Medical Residents in the General Medicine In-Training Examination: Comparison Study.

BACKGROUND: The reliability of GPT-4, a state-of-the-art expansive language model specializing in clinical reasoning and medical knowledge, remains largely unverified across non-English languages. OBJECTIVE: This study aims to compare fundamental clinical competencies between Japanese residents and GPT-4 by using the General Medicine In-Training Examination (GM-ITE). METHODS: We used the GPT-4 model provided by OpenAI and the GM-ITE examination questions for the years 2020, 2021, and 2022 to conduct a comparative analysis. This analysis focused on evaluating the performance of individuals who were concluding their second year of residency in comparison to that of GPT-4. Given the current abilities of GPT-4, our study included only single-choice exam questions, excluding those involving audio, video, or image data. The assessment included 4 categories: general theory (professionalism and medical interviewing), symptomatology and clinical reasoning, physical examinations and clinical procedures, and specific diseases. Additionally, we categorized the questions into 7 specialty fields and 3 levels of difficulty, which were determined based on residents' correct response rates. RESULTS: Upon examination of 137 GM-ITE questions in Japanese, GPT-4 scores were significantly higher than the mean scores of residents (residents: 55.8%, GPT-4: 70.1%; P<.001). In terms of specific disciplines, GPT-4 scored 23.5 points higher in the "specific diseases," 30.9 points higher in "obstetrics and gynecology," and 26.1 points higher in "internal medicine." In contrast, GPT-4 scores in "medical interviewing and professionalism," "general practice," and "psychiatry" were lower than those of the residents, although this discrepancy was not statistically significant. Upon analyzing scores based on question difficulty, GPT-4 scores were 17.2 points lower for easy problems (P=.007) but were 25.4 and 24.4 points higher for normal and difficult problems, respectively (P<.001). In year-on-year comparisons, GPT-4 scores were 21.7 and 21.5 points higher in the 2020 (P=.01) and 2022 (P=.003) examinations, respectively, but only 3.5 points higher in the 2021 examinations (no significant difference). CONCLUSIONS: In the Japanese language, GPT-4 also outperformed the average medical residents in the GM-ITE test, originally designed for them. Specifically, GPT-4 demonstrated a tendency to score higher on difficult questions with low resident correct response rates and those demanding a more comprehensive understanding of diseases. However, GPT-4 scored comparatively lower on questions that residents could readily answer, such as those testing attitudes toward patients and professionalism, as well as those necessitating an understanding of context and communication. These findings highlight the strengths and limitations of artificial intelligence applications in medical education and practice.

Etoricoxib enhances aryl hydrocarbon receptor activity.

Etoricoxib is a nonsteroidal anti-inflammatory drug (NSAID) that possesses properties that include reducing inflammation and relieving pain and fever. Etoricoxib is an oral medication that selectively inhibits cyclooxygenase-2 with high efficacy. Controversies about its cardiovascular side effects have long existed. The aryl hydrocarbon receptor (AhR) is a cytoplasmic receptor that plays a key role in the metabolism of xenobiotics and many physiological functions. 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) is a tryptophan metabolite and endogenous AhR agonist. Activation of AhR by its ligand induces upregulation of AhR-targeted cytochrome P450 (CYP) 1A1 expression. We found that etoricoxib (10-60 µM) induced CYP1A1 mRNA and protein expressions and the transcriptional activity of AhR mediated by the aryl hydrocarbon response element (AHRE) in both mouse Hepa-1c1c7 and human HepG2 cells. Its induction did not appear in AhR signaling-deficient cells, and was inhibited by the AhR antagonist, CH-223191. Etoricoxib was able to induced the translocalization of AhR from cytosol into nucleus. Etoricoxib also worked synergistically with ITE to further increase the expression of CYP1A1 mRNA and protein in human cells. The synergistic effect was higher in cells with than cells without overexpression of AhR. In summary, etoricoxib is an agonist of AhR in both mouse and human cells. Etoricoxib has a synergistic effect on ITE-induced CYP1A1 expression in human cells. The effect of etoricoxib on AhR and ITE on endothelial cells and cardiomyocytes should be further elucidated to in hope to clarify the mechanism of increased cardiovascular events in COX-2 inhibitors and etoricoxib.

Differential Effect of ITE on the Aryl Hydrocarbon Receptor Signaling in Breast Cancer Tissue: A Histopathological Study / Efecto Diferencial de ITE en la Señalización del Receptor de Hidrocarburo de Arilo en Tejido de Cáncer de Mama: Un Estudio Histopatológico

SUMMARY: Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that is highly expressed in various types of cancers including breast cancer. However, the role of AhR with its endogenous ligand 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) on the progression of breast cancer remains poorly understood. We aimed to investigate cell proliferation and migration states in breast cancer after activating AhR with the endogenous ligand ITE. Breast cancer tissue was evaluated by cell lines, immunohistochemistry, reverse transcription-polymerase chain reaction, cell proliferation, flow cytometry, migration assays and western blot techniques. We found that AhR was widely expressed in breast cancer tissues and metastasis lymph node tissues, but not in normal tissues. The expression AhR was independent between the age, grades and TNM classifications for breast cancer tissues. ITE treatment significantly induced the activation of AhR in a time-dependent manner in both MCF-7 and T47D breast cancer cell lines. Meanwhile, ITE did not affect the cell migration but significantly suppressed the cell proliferation in estrogen receptor positive (ER+) MCF-7 andT47D cells, which probably attribute to the induction of cell cycle arrest in G1 phase and shortened S phase. Further mechanism study showed that ERK1/2 and AKT signaling were required for the activation of AhR in MCF-7 cells. These data suggest that AhR is a potential new target for treating patients with breast cancer. ITE may be more potentially used for therapeutic intervention for breast cancer with the kind of ER(+).

El receptor de hidrocarburo de arilo (AhR) es un factor de transcripción activado por ligando que se expresa en gran medida en varios tipos de cáncer, incluido el cáncer de mama. Sin embargo, el papel de AhR con su ligando endógeno 2- (1'H-indol-3'-carbonil)-tiazol-4-ácido carboxílico metil éster (ITE) en la progresión del cáncer de mama sigue siendo poco conocido. Nuestro objetivo fue investigar la proliferación celular y los estados de migración en el cáncer de mama después de activar AhR con el ligando endógeno ITE. El tejido de cáncer de mama se evaluó mediante líneas celulares, inmunohistoquímica, reacción en cadena de la polimerasa con transcriptasa inversa, proliferación celular, citometría de flujo, ensayos de migración y técnicas de transferencia Western. Descubrimos que AhR se expresó ampliamente en tejidos de cáncer de mama y en linfonodos con metástasis, pero no en tejidos normales. La expresión AhR fue independiente entre la edad, grados y clasificaciones TNM para tejidos de cáncer de mama. El tratamiento con ITE indujo significativamente la activación de AhR de manera dependiente del tiempo en las líneas celulares de cancer de mama MCF-7 y T47D. Mientras tanto, ITE no afectó la migración celular, pero suprimió significativamente la proliferación celular en células MCF-7 y T47D con receptor de estrógeno positivo (ER+), lo que probablemente se atribuye a la inducción de la detención del ciclo celular en la fase G1 y la fase S acortada. Un estudio adicional del mecanismo mostró que las señales de ERK1/2 y AKT eran necesarias para la activación de AhR en las células MCF-7. Estos datos sugieren que AhR es un nuevo objetivo potencial para el tratamiento de pacientes con cáncer de mama. ITE puede ser utilizado más potencialmente en la intervención terapéutica para el cáncer de mama con el tipo de ER (+).

Growth, structure, and morphology of van der Waals epitaxy Cr1+δTe2 films.

The preparation of two-dimensional magnetic materials is a key process to their applications and the study of their structure and morphology plays an important role in the growth of high-quality thin films. Here, the growth, structure, and morphology of Cr1+δTe2 films grown by molecular beam epitaxy on mica with variations of Te/Cr flux ratio, growth temperature, and film thickness have been systematically investigated by scanning tunneling microscopy, reflection high-energy electron diffraction, scanning electron microscope, and X-ray photoelectron spectroscopy. We find that a structural change from multiple phases to a single phase occurs with the increase in growth temperature, irrespective of the Cr/Te flux ratios, which is attributed to the desorption difference of Te atoms at different temperatures, and that the surface morphology of the films grown at relatively high growth temperatures (≥ 300 °C) exhibits a quasi-hexagonal mesh-like structure, which consists of nano-islands with bending surface induced by the screw dislocations, as well as that the films would undergo a growth-mode change from 2D at the initial stage in a small film thickness (2 nm) to 3D at the later stage in thick thicknesses (12 nm and 24 nm). This work provides a general model for the study of pseudo-layered materials grown on flexible layered substrates.

Radical rubrics: implementing the critical and creative thinking general capability through an ecological approach.

This article details how and why we have developed a flexible and responsive process-based rubric exemplar for teaching, learning, and assessing critical and creative thinking. We hope to contribute to global discussions of and efforts toward instrumentalising the challenge of assessing, but not standardising, creativity in compulsory education. Here, we respond to the key ideas of the four interrelated elements in the critical and creative thinking general capability in the Australian Curriculum learning continuum: inquiring; generating ideas, possibilities, actions; reflecting on thinking processes; and analysing, synthesising and evaluating reasoning and procedures. The rubrics, radical because they privilege process over outcome, have been designed to be used alongside the current NAPLAN tests in Years 5, 7 and 9 to build an Australian-based national creativity measure. We do so to argue the need for local and global measures of creativity in education as the first round of testing and results of the PISA Assessment of Creative Thinking approach and to contribute to the recognition of creative thinking (and doing) as a core twenty-first century literacy alongside literacy and numeracy.

Pruning the Communication Bandwidth between Reinforcement Learning Agents through Causal Inference: An Innovative Approach to Designing a Smart Grid Power System.

Electricity demands are increasing significantly and the traditional power grid system is facing huge challenges. As the desired next-generation power grid system, smart grid can provide secure and reliable power generation, and consumption, and can also realize the system's coordinated and intelligent power distribution. Coordinating grid power distribution usually requires mutual communication between power distributors to accomplish coordination. However, the power network is complex, the network nodes are far apart, and the communication bandwidth is often expensive. Therefore, how to reduce the communication bandwidth in the cooperative power distribution process task is crucially important. One way to tackle this problem is to build mechanisms to selectively send out communications, which allow distributors to send information at certain moments and key states. The distributors in the power grid are modeled as reinforcement learning agents, and the communication bandwidth in the power grid can be reduced by optimizing the communication frequency between agents. Therefore, in this paper, we propose a model for deciding whether to communicate based on the causal inference method, Causal Inference Communication Model (CICM). CICM regards whether to communicate as a binary intervention variable, and determines which intervention is more effective by estimating the individual treatment effect (ITE). It offers the optimal communication strategy about whether to send information while ensuring task completion. This method effectively reduces the communication frequency between grid distributors, and at the same time maximizes the power distribution effect. In addition, we test the method in StarCraft II and 3D environment habitation experiments, which fully proves the effectiveness of the method.

Islamic Republic of Iran - a surprisingly progressive centre of medical tourism.

The Islamic Republic of Iran is a very progressive state in the field of medical research and its application. Although the country is fully subject to Islamic law (shari'a) and the influence of Shi'ite clerics, the development of medical science is not limited at all; Shi'ite medical ethics (unlike Sunnite) allows most of the modern medical techniques. Due to this attitude, Iran specializes today in many techniques that are prohibited in other countries for religious or ethical reasons. For example, Iranian research on cloning, cell and gene therapy reaches the world level, patients can use a third-party donor program and surrogacy for infertility treatment, the sale of kidney for transplantation was legalized, gender reassignment surgery is performed, and the country is a centre of cosmetic surgery. All of these services (excluding transplantation) are also offered to foreign patients. Thanks to these unlimited possibilities, high quality and low price, Iran has been currently gaining a strong position in the medical tourism market, not only in the Middle East region, but also worldwide.

Conduct and Implementation of Personalized Trials in Research and Practice.

The mainstay of evidence development in medicine is the parallel-group randomized controlled trial (RCT), which generates estimates of treatment efficacy or effectiveness for the average person in the trial. In contrast, personalized trials (sometimes referred to as 'single-person trials' or 'N-of-1 trials') assess the comparative effectiveness of two or more treatments in a single individual. These single-subject, randomized crossover trials have been used in a scattershot fashion in medicine for over 40 years but have not been widely adopted. An important barrier is the paucity of strong evidence that personalized trials improve outcomes. However, the principal impediment may have less to do with proof of efficacy than with practical aspects of design and implementation. These include decisions about treatment regimen flexibility, blinding, and washout periods as well as organizational, clinician, and patient-level challenges. After reviewing the essential elements of personalized trials, this article addresses these speed bumps and fundamentally asks, 'Why have personalized trials not been more widely adopted, and how can they be made more readily deployable and useful?' The article concludes by suggesting ways in which emerging technologies and approaches promise to overcome existing barriers and open promising vistas for the next generation of personalized-trial researchers and practitioners.

Education based on publicly-available keyword data is associated with decreased stress and improved trajectory of in-training exam performance.

STUDY OBJECTIVE: This study aimed to assess the impact of data-driven didactic sessions on metrics including fund of knowledge, resident confidence in clinical topics, and stress in addition to American Board of Anesthesiology In-Training Examination (ITE) percentiles. DESIGN: Observational mixed-methods study. SETTING: Classroom, video-recorded e-learning. SUBJECTS: Anesthesiology residents from two academic medical centers. INTERVENTIONS: Residents were offered a data-driven didactic session, focused on lifelong learning regarding frequently asked/missed topics based on publicly-available data. MEASUREMENTS: Residents were surveyed regarding their confidence on exam topics, organization of study plan, willingness to educate others, and stress levels. Residents at one institution were interviewed post-ITE. The level and trend in ITE percentiles were compared before and after the start of this initiative using segmented regression analysis. RESULTS: Ninety-four residents participated in the survey. A comparison of pre-post responses showed an increased mean level of confidence (4.5 ± 1.6 vs. 6.2 ± 1.4; difference in means 95% CI:1.7[1.5,1.9]), sense of study organization (3.8 ± 1.6 vs. 6.7 ± 1.3;95% CI:2.8[2.5,3.1]), willingness to educate colleagues (4.0 ± 1.7 vs. 5.7 ± 1.9;95% CI:1.7[1.4,2.0]), and reduced stress levels (5.9 ± 1.9 vs. 5.2 ± 1.7;95% CI:-0.7[-1.0,-0.4]) (all p < 0.001). Thirty-one residents from one institution participated in the interviews. Interviews exhibited qualitative themes associated with increased fund of knowledge, accessibility of high-yield resources, and domains from the Kirkpatrick Classification of an educational intervention. In an assessment of 292 residents from 2012 to 2020 at one institution, there was a positive change in mean ITE percentile (adjusted intercept shift [95% CI] 11.0[3.6,18.5];p = 0.004) and trajectory over time after the introduction of data-driven didactics. CONCLUSION: Data-driven didactics was associated with improved resident confidence, stress, and factors related to wellness. It was also associated with a change from a negative to positive trend in ITE percentiles over time. Future assessment of data-driven didactics and impact on resident outcomes are needed.

Do the selection criteria of internal medicine residency program predict resident performance?

BACKGROUND: Well-performing physician reflects the success of the residency program in selecting the best candidates for training. This study aimed to evaluate the selection criteria, mainly the United States Medical Licensing Examination (USMLE) Step 2 Clinical Knowledge (CK) results and applicants' status as international or locally trained applicants, used by the medical education department and the internal medicine residency program in Hamad Medical Corporation in Qatar to predict the residents' performance during their training. METHODS: A retrospective chart review was performed for three batches of graduates who started residency training in 2011, 2012, and 2013. Each group completed 4 years of training. The USMLE Step 2 CK status of the applicant, in-training exam (ITE) scores, formative evaluation scores, Arab Board written and clinical exams pass rate, and other indicators were analyzed. Statistical analysis included chi squares and independent t-test to identify associations. Multivariable analyses were conducted using logistic and linear regressions to test for adjusted associations. RESULTS: The study included 118 (81 international/37 locally trained applicants) internal medicine residents. The ITE score correlated positively with the USMLE Step 2 CK score (r = 0.621, r = 0.587, r = 0.576, r = 0.571, p < 0.001) over the 4 years of training and among the international compared with locally trained applicants (p < 0.001). The rate of passing part 1 and 2 written exam of the Arab Board was higher in international than in local applicants, whereas clinical Arab Board exam and formative evaluation were not associated with any criteria. CONCLUSIONS: Higher USMLE Step 2 CK score correlated with better performance on ITE but not with other performance indicators, whereas international applicants did better in both ITE and Arab Board written exam than local applicants. These variables may provide reasonable predictors of well-performing physicians.

Difference in the general medicine in-training examination score between community-based hospitals and university hospitals: a cross-sectional study based on 15,188 Japanese resident physicians.

BACKGROUND: The general medicine in-training examination (GM-ITE) is designed to objectively evaluate the postgraduate clinical competencies (PGY) 1 and 2 residents in Japan. Although the total GM-ITE scores tended to be lower in PGY-1 and PGY-2 residents in university hospitals than those in community-based hospitals, the most divergent areas of essential clinical competencies have not yet been revealed. METHODS: We conducted a nationwide, multicenter, cross-sectional study in Japan, using the GM-ITE to compare university and community-based hospitals in the four areas of basic clinical knowledge". Specifically, "medical interview and professionalism," "symptomatology and clinical reasoning," "physical examination and clinical procedures," and "disease knowledge" were assessed. RESULTS: We found no significant difference in "medical interview and professionalism" scores between the community-based and university hospital residents. However, significant differences were found in the remaining three areas. A 1.28-point difference (95% confidence interval: 0.96-1.59) in "physical examination and clinical procedures" in PGY-1 residents was found; this area alone accounts for approximately half of the difference in total score. CONCLUSIONS: The standardization of junior residency programs and the general clinical education programs in Japan should be promoted and will improve the overall training that our residents receive. This is especially needed in categories where university hospitals have low scores, such as "physical examination and clinical procedures."

The aryl hydrocarbon receptor ligand ITE inhibits cell proliferation and migration and enhances sensitivity to drug-resistance in hepatocellular carcinoma.

Aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, is considered as a crucial gene during tumor formation and progress. Among various ligands, 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) has been evaluated to share a broad spectrum of biological activities. However, the specific effects and potential mechanisms of ITE against hepatocellular carcinoma remain unclear. Here we explored whether ITE exerted antitumor activity against hepatocellular carcinoma (HCC) cells and its potential mechanisms in vitro and in vivo. We found that ITE could markedly inhibit proliferation of HCCLM3 and SMMC-7721 cells and induce G0/G1 arrest and apoptosis with alterations of expressions of the related proteins. Also, ITE could prohibit the process of migration and invasion evaluated by transwell assay. Moreover, ITE exhibited remarkable capability to repress the growth of HCCLM3-SR cells and induce apoptosis in contrast to sorafenib. Additionally, ITE also showed potent antitumor activity against the HCCLM3 xenograft by prohibiting tumor growth without any toxicity to mice. Mechanistically, AHR activation by ITE was attributed to inhibition of HCC cells as AHR knockdown would abolish ITE-induced suppression in HCC cells, and overexpression of AHR would potentiate antitumor activity regulated by ITE. Our data suggested that ITE manifested a marked antitumor effect against HCC cells both in vitro and in vivo via AHR activation mainly through inducing G1/G0 arrest and apoptosis and inhibiting the process of migration and invasion. Furthermore, we also found the PI3K/AKT pathway was involved in sorafenib-induced resistance and ITE could restore sensitivity by suppressing the PI3K/AKT pathway. Collectively, our study revealed that ITE would be a promising therapeutic agent to deal with HCC and an alternative for drug-resistant HCC.

Impact of general medicine rotation training on the in-training examination scores of 11, 244 Japanese resident physicians: a Nationwide multi-center cross-sectional study.

BACKGROUND: Although general medicine (GM) faculty in Japanese medical schools have an important role in educating medical students, the importance of residents' rotation training in GM in postgraduate education has not been sufficiently recognized in Japan. To evaluate the relationship between the rotation of resident physicians in the GM department and their In-Training Examination score. METHODS: This study is a nationwide multi-center cross-sectional study in Japan. Participants of this study are Japanese junior resident physicians [postgraduate year (PGY)-1 and PGY-2] who took the General Medicine In-Training Examination (GM-ITE) in fiscal years 2016 to 2018 at least once (n = 11,244). The numbers of participating hospitals in the GM-ITE were 381, 459, and 503 in 2016, 2017, and 2018.The GM-ITE score consisted of four categories (medical interview/professionalism, symptomatology/clinical reasoning, physical examination/procedure, and disease knowledge). We evaluated relationship between educational environment (including hospital information) and the GM-ITE score. RESULTS: A total of 4464 (39.7%) residents experienced GM department rotation training. Residents who rotated had higher total scores than residents who did not rotate (38.1 ± 12.1, 36.8 ± 11.7, and 36.5 ± 11.5 for residents who experienced GM rotation training, those who did not experience this training in hospitals with a GM department, and those who did not experience GM rotation training in hospitals without a GM department, p = 0.0038). The association between GM rotation and competency remained after multivariable adjustment in the multilevel model: the score difference between GM rotation training residents and non-GM rotation residents in hospitals without a GM department was estimated as 1.18 (standard error, 0.30, p = 0.0001), which was approximately half of the standard deviation of random effects due to hospital variation (estimated as 2.00). CONCLUSIONS: GM rotation training improved the GM-ITE score of residents and should be considered mandatory for junior residents in Japan.

The putative endogenous AHR ligand ITE reduces JAG1 and associated NOTCH1 signaling in triple negative breast cancer cells.

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor. Triple negative breast cancer (TNBC) is the most aggressive breast cancer subtype. TNBC expresses AHR and AHR ligands have anti-cancer activity in TNBC. The aggressiveness of TNBC is due in part to JAG1-NOTCH1 signaling. ITE is a putative endogenous AHR ligand. We show that ITE reduces the expression of JAG1 the amount of Notch 1 intracellular domain (NICD1) and the phosphorylation of STAT3 (at tyrosine 705) in TNBC MDA-MB-231 cells. The STAT3 inhibitor STATTIC also reduced JAG1. STAT3, thus, mediates regulation of JAG1 in MDA-MB-231 cells. Reducing the expression of JAG1 with short interfering RNA decreases the growth, migration and invasiveness of MDA-MB-231 cells. JAG1, therefore, has cellular effects in MDA-MB-231 cells under basal conditions. We consequently evaluated if exposing cells to greater amounts of JAG1 would counteract ITE cellular effects in MDA-MB-231 cells. The results show that JAG1 does not counteract the cellular effects of ITE. JAG1, thus, has no effect on growth or invasiveness in MDA-MB-231 cells treated with ITE. JAG1, therefore, has context dependent roles in MDA-MB-231 cells (basal versus ITE treatment). The results also show that other pathways, not inhibition of the JAG1-NOTCH1 pathway, are important for mediating the growth and invasive inhibitory effect of ITE on MDA-MB-231 cells.

ITE promotes hypoxia-induced transdifferentiation of human pulmonary arterial endothelial cells possibly by activating transforming growth factor-ß/Smads and MAPK/ERK pathways.

This study aimed to investigate the transdifferentiation of human pulmonary arterial endothelial cells (HPAECs) into smooth muscle like (SM-like) cells under hypoxic conditions and reveal the role of endogenous small molecular compound 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylicacid methyl ester (ITE) in this process. HPAECs were treated by hypoxia and hypoxia + ITE with different durations. The endothelial markers (CD31 and VE-cad) and smooth muscle markers (α-SMA, SM22α, and OPN) were investigated by immunofluorescence double staining, and their expressions, along with the differentiation regulators transforming growth factor-ß (TGF-ß) ligands and downstream signals including TGF-ß1, bone morphogenetic protein (BMP2), BMP9, Samd2/3, ERK, and p38 MAPK, were determined by Western blot analysis. The viability and proliferation of HPAECs were detected by Cell Counting Kit-8 (CCK-8) method and bromodeoxyuridine (BrdU) assays. As a result, hypoxia induced HPAECs transdifferentiation from paving-stone-like into polygonal or spindle cells, whose number increased greatly after additional ITE stimulation for 7 days. Compared with the normoxic HPAECs, the expression of endothelial markers reduced and smooth muscle markers were enhanced with the extension of hypoxia + ITE treatment, and meanwhile the cell viability increased significantly. Hypoxia could promote expression of TGF-ß1 protein rather than BMP2 and BMP9, and regulate phosphorylation levels of Samd2/3, ERK and p38 MAPK in different manners. In conclusion, ITE can promote the hypoxia-induced transdifferentiation of HPAECs into SM-like cells via TGF-ß/Smads and MAPK/ERK pathways.

ITE, an endogenous aryl hydrocarbon receptor ligand, suppresses endometrial cancer cell proliferation and migration.

BACKGROUND: Identification of new molecular targets for the treatment of endometrial cancer (EC) is an important clinical goal, especially for the patients which were resistant to conventional therapies. The aryl hydrocarbon receptor (AhR) is a ligand- activated transcription factor known primarily as the mediator of dioxin toxicity. However, the AhR can also inhibit cellular proliferation in a ligand-dependent manner and act as a tumor suppressor in mice, thus may be a potential anticancer target. In this study, we investigated if the endogenous AhR ligand 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) regulated proliferation and migration of EC cells via AhR. METHODS: We used quantitative real-time PCR and western blot to assess the expression of AhR in EC tissues and paired adjacent normal tissues. In addition, we conducted transwell assay to test whether the treatment of ITE altered the locomotive potential and proliferation of EC cells. Next, we conducted mouse xenograft models to further explore the in vivo effect of ITE. RESULTS: We found that the AhR protein and RNA levels were increased mildly in EC tissues relative to the para-tumor normal endometrial tissues. Besides, ITE suppressed EC cells proliferation and migration in vitro, and also suppressed EC cells xenograft growth in mice. CONCLUSIONS: Our results strongly supported the possibility of using the ITE as a small molecular compound for the treatment of EC.

Role of Aryl Hydrocarbon Receptor (AhR) in the Regulation of Immunity and Immunopathology During Trypanosoma cruzi Infection.

Resistance to Trypanosoma cruzi infection is dependent on a rapid induction of Th1-type and CD8+ T cell responses that should be promptly balanced to prevent immunopathology. T. cruzi-infected B6 mice are able to control parasite replication but show a limited expansion of Foxp3+regulatory T (Treg) cells that results in the accumulation of effector immune cells and the development of acute liver pathology. AhR is a ligand-activated transcription factor that promotes Treg cell development and suppression of pro-inflammatory cytokine production in dendritic cells, altering the course of adaptive immune response and the development of immunopathology. Here, we used different AhR-dependent activation strategies aiming to improve the Treg response, and B6 congenic mice carrying a mutant AhR variant with low affinity for its ligands (AhRd) to evaluate the role of AhR activation by natural ligands during experimental T. cruzi infection. The outcome of TCDD or 3-HK plus ITE treatments indicated that strong or weak AhR activation before or during T. cruzi infection was effective to regulate inflammation improving the Treg cell response and regularizing the ratio between CD4+ CD25- to Treg cells. However, AhR activation shifted the host-parasite balance to the parasite replication. Weak AhR activation resulted in Treg promotion while strong activation differentially modulated the susceptibility and resistance of cell death in activated T and Treg cells and the increase in TGF-ß-producing Treg cells. Of note, T. cruzi-infected AhRd mice showed low levels of Treg cells associated with strong Th1-type response, low parasite burden and absence of liver pathology. These mice developed a Treg- and Tr1-independent mechanism of Th1 constriction showing increased levels of systemic IL-10 and IL-10-secreting CD4+ splenocytes. In addition, AhR activation induced by exogenous ligands had negative effects on the development of memory CD8+ T cell subsets while the lack/very weak activation in AhRd mice showed opposite results, suggesting that AhR ligation restricts the differentiation of memory CD8+T cell subsets. We propose a model in which a threshold of AhR activation exists and may explain how activation or inhibition of AhR-derived signals by infection/inflammation-induced ligands, therapeutic interventions or exposure to pollutants can modulate infections/diseases outcomes or vaccination efficacy.

Targeted deletion of the aryl hydrocarbon receptor in dendritic cells prevents thymic atrophy in response to dioxin.

In nearly every species examined, administration of the persistent environmental pollutant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin, TCDD) causes profound immune suppression and thymic atrophy in an aryl hydrocarbon receptor (AhR) dependent manner. Moreover, TCDD alters the development and differentiation of thymocytes, resulting in decreases in the relative proportion and absolute number of double positive (DP, CD4+CD8+) thymocytes, as well as a relative enrichment in the relative proportion and absolute number of double negative (DN, CD4-CD8-) and single-positive (SP) CD4+CD8- and CD4-CD8+ thymocytes. Previous studies suggested that the target for TCDD-induced thymic atrophy resides within the hemopoietic compartment and implicated apoptosis, proliferation arrest of thymic progenitors, and emigration of DN thymocytes to the periphery as potential contributors to TCDD-induced thymic atrophy. However, the precise cellular and molecular mechanisms involved remain largely unknown. Our results show that administration of 10 µg/kg TCDD and 8 mg/kg 2-(1H-indol-3-ylcarbonyl)-4-thiazolecarboxylic acid methyl ester (ITE) induced AhR-dependent thymic atrophy in mice on day 7, whereas 100 mg/kg indole 3-carbinol (I3C) did not. Though our studies demonstrate that TCDD triggers a twofold increase in the frequency of apoptotic thymocytes, TCDD-induced thymic atrophy is not dependent on Fas-FasL interactions, and thus, enhanced apoptosis is unlikely to be a major mechanistic contributor. Finally, our results show that activation of the AhR in CD11c+ dendritic cells is directly responsible for TCDD-induced alterations in the development and differentiation of thymocytes, which results in thymic atrophy. Collectively, these results suggest that CD11c+ dendritic cells play a critical role in mediating TCDD-induced thymic atrophy and disruption of T lymphocyte development and differentiation in the thymus.

Human AHR functions in vascular tissue: Pro- and anti-inflammatory responses of AHR agonists in atherosclerosis.

Despite decades of intense research physiologic aryl hydrocarbon receptor (AHR) functions have not been elucidated. Challenges include marked species differences and dependence on cell type and cellular context. A previous commentary on human AHR functions in skin and intestine has been extended to vascular tissue. Similar functions appear to be operating in vascular tissue including microbial defense, modulation of stem/progenitor cells as well as control of immunity and inflammation. However, AHR functions are Janus faced: Detrimental AHR functions in vascular tissue are well documented, e.g., upon exposure to polycyclic aromatic hydrocarbons in cigarette smoke leading to oxidative stress and generation of oxidized LDL. Modified LDL particles accumulate in macrophages and smooth muscle-derived pro-inflammatory foam cells, the hallmark of atherosclerosis. On the other hand, numerous anti-inflammatory AHR agonists have been identified including bilirubin and quercetin. Mechanisms as to how AHR produces pro- and anti-inflammatory responses in the vascular system need further investigation.