Stages Of Colonization Research Articles

Validating the use of machine-learning cancer staging algorithms for Medicare cost analyses.

e13548 Background: Administrative claims provide valuable real-world insight into the care of cancer patients; however, claims data lacks cancer stage information. This limitation constrains research on the value of early diagnosis and treatment as well as on the costs and savings associated with increased cancer screening. In prior work, our team used the SEER-Medicare data to develop machine learning (ML) algorithms to stage non-small cell lung (NSCLC), colon (CC), and rectal (RC) cancer patients using clinical flags derived from claims data. These algorithms were 69% (RC), 78% (NSCLC), and 83% (CC) accurate at matching incident cancer patients with their SEER-recorded AJCC stage (SEER-stage) at diagnosis. This work sought to test whether these ML algorithms are sufficiently accurate for use in claim cost analyses. Methods: Incident NSCLC, CC, and RC patients were identified using 2016-2017 SEER-Medicare data and assigned a cancer stage using a claims-based predictive multinomial logistic regression model (R Statistical Software - v4.1.2 R Core Team 2021; nnet package - Venables and Ripley 2002). Patients’ cumulative medical and pharmacy costs were summarized for 12 months starting with patients’ index month. Patients’ Medicare index month was set equal to the month of their first claim with a cancer diagnosis. Patients’ SEER index month was set equal to the diagnosis month associated with their incident tumor record in SEER. Patients with each cancer type were then grouped two ways - by ML-stage and by SEER-stage. Median patient costs were compared between stage groups for each cancer type and differences tested for statistical significance using Wilcoxon Rank-Sum Testing. Results: For NSCLC and CC, raw differences in median 12-month claim costs between the ML- and SEER-stage cohorts were small (1%-4%). Cost differences for RC were higher (7%-17%). ML and SEER costs were not significantly different (p > 0.05) between later-stage cohorts (NSCLC stages 3 and 4, CC stages 2C/3 and 4, and RC stage 4); however, early-stage groups were always significantly different (p < 0.05). Conclusions: Although costs were not statistically equivalent across all stage groups, the similarity of ML and SEER costs across higher-stage cohorts and small raw differences in median costs for each NSCLC and CC group suggests that ML algorithms with higher accuracy may be used to develop costs from administrative data for stage shift modeling and cost tradeoff analyses. [Table: see text]

Electronic frailty index predicts 30-day mortality from chemotherapy in breast, colorectal and lung cancer.

12009 Background: Older and frail patients with cancer (Ca) often receive less aggressive treatment and as a result have worse survival. Current methods of assessing fitness (performance status) for intensive treatment such as chemotherapy are inadequate. The complexity of geriatric assessments, lack of training and time pressures in busy clinics, mean that better solutions are needed. A UK initiative - the electronic frailty index (eFI) - is derived from a cumulative deficit frailty model and provides a measure of frailty alongside pre-existing conditions such as issues with mobility, fractures, falls, memory, sight, hearing , anaemia, tremor, diabetes, heart, thyroid, skin, respiratory, cerebrovascular, circulation, social vulnerability, and polypharmacy (36 fields) (Clegg et al). Patients are classified into the following groups: no frailty, mild, moderate or severe frailty. We used the same methodology to investigate whether eFI predicts adverse outcomes of chemotherapy in frail patients with Ca. Methods: The study conducted retrospective data analysis of Ca patients treated with chemotherapy from Public Health England (PHE) Systemic Chemotherapy Dataset (SACT) years 2015-2018. Eligible patients had stage II - III breast Ca, stage III colon Ca or stage IIIB–IV non-small-cell lung Ca (NSCLC). The data from SACT was linked with hospital episodes' statistics (obtained from NHS-Digital) to calculate 30-day SACT mortality, overall survival and hospital admissions. EFI was calculated from the above 35 fields; polypharmacy was not available from NHS-Digital data. Results: The eFI was calculated for 78799 patients: colorectal 17951, lung 22052, and breast 38796. 20388 patients were ≥ 70y. o. and 58411 were < 70y.o. Most patients were fit with an eFI score of 0-69% (54563), 19% (15,295) had mild frailty, 7.7% (6104)- moderate, and 3.6% (2837) had severe frailty. 4.2% (3356) of patients died within 30 days of SACT. For colorectal Ca patients the risk of dying within 30 days of SACT in patients ≥70y.o was twice that of the < 70y.o (OR 2.04 -CI 1.58 - 2.64); patients with mild eFI did not differ- OR: 1.07 (CI 0.78-1.45), moderate frailty: 1.6 (CI 1.1-2.33) and severe frailty: 2.13 (CI 1.34-3.39). In breast Ca patients, 30-day mortality for ≥70y.o. was 6.38 times higher than for < 70y.o (95% CI 4.29-9.49); eFI for mild frailty- OR of 1.45 (95% CI 0.78-2.71), moderate frailty-OR of 3.5 (95%CI 1.82-6.75) and severe frailty 5.73 (95% CI 2.66-12.3). The 30-day mortality in lung cancer in ≥70y.o and < 70y.o did not differ with OR 0.95 (95% CI 0.88-1.03) for ≥70y.o. Patients with mild frailty had OR for 30-day mortality of 1.17 (95% CI 1.07-1.28), moderate frailty-OR of 1.28 (95%CI 1.15-1.44) and severe frailty 1.48 (95% CI 1.28-1.77). Conclusions: The eFI closely predicts poor outcomes from SACT, particularly in early breast and colon cancer, and requires further evaluation in a prospective study.

Underutilization or appropriate care? Assessing adjuvant chemotherapy use and survival in 3 heterogenous subpopulations with stage II/III colorectal cancer within a large integrated health system.

BACKGROUND: Clinical guidelines have recommended adjuvant chemotherapy (ACT) for patients with high-risk stage II colon cancer, although the survival benefit is unclear. ACT is also recommended for patients with stage III colon cancer to reduce the risk of recurrence and mortality. For stage II/III rectal cancer, however, the role of perioperative chemotherapy (PCT, adjuvant or neoadjuvant) remains controversial, resulting in substantial variation in its use in clinical practice. OBJECTIVES: To understand real-world use and predictors of ACT or PCT use and survival outcomes in 3 heterogeneous patient groups with colorectal cancer (CRC), and to inform the evidence gap between guideline-based care and clinical practice. METHODS: This retrospective cohort study included patients with an initial stage II/III CRC diagnosis between 2008 and 2013 identified from Kaiser Permanente Southern California electronic health record databases. Patients were eligible if they were aged 18-74 years at diagnosis and received primary curative surgery. We fitted mixed effects logistic regression models to evaluate predictors of ACT receipt and Cox proportional hazards models on propensity score-matched (PS-matched) samples to assess the association between ACT/PCT receipt and survival. RESULTS: We included 1,690 patients with colon cancer (stage II: 820 and stage III: 870) and 587 patients with rectal cancer (stage II: 241 and stage III: 346). We found that 65% of patients with high-risk stage II colon cancer, 15% of those with stage III colon, and 15% of those with stage II/III rectal cancer did not receive ACT/PCT. Patients with stage II colon cancer with T4 stage (odds ratio [OR] = 5.79, 95% CI = 3.33 - 10.06) and a lower comorbidity score were more likely to receive ACT (high vs low Charlson score: OR = 0.69, 95% CI = 0.55 - 0.87). Patients with stage III rectal cancer were more likely to receive PCT than those with stage II disease (OR = 7.85, 95% CI = 2.07 - 29.74). Patients with another cancer diagnosis prior to CRC diagnosis were less likely to receive PCT (OR = 0.37, 95% CI = 0.16 - 0.85). ACT/PCT use was associated with improved overall survival among patients with high-risk stage II colon cancer (PS-matched hazard ratio [HR] = 0.42, 95% CI = 0.25 - 0.70) and those with stage III CRC (stage III colon: PS-matched HR = 0.3, 95% CI = 0.25 - 0.36; stage III rectal: PS-matched HR = 0.2, 95% CI = 0.13 - 0.31). CONCLUSIONS: We found potential underuse of appropriate chemotherapy treatment in patients with high-risk stage II colon cancer and stage III CRC. Clinicians' and providers' decisions on ACT administration may not be fully guided by the risk of recurrence and 5-year survival benefits in stage II colon cancer. DISCLOSURES: This research was supported by the National Cancer Institute of the National Institutes of Health (NIH) (under R37-CA218413). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

Preliminary study of microRNA expression profiling in non-metastatic colorectal cancer.

e15528 Background: MicroRNAs (miRNAs) are non-coding single-stranded RNAs (18–25 nucleotides in length) that regulate gene expression at the posttranscriptional level by promoting the degradation of mRNAs or by blocking mRNA translation. However, the clinical significance in colon cancer is not yet determined. This study aims to identify differentially expressed miRNAs in colorectal cancer by comparing colon cancerous tissues with normal tissues, exploring the potential roles. Methods: The miRNA expression microarray was employed on tumors from patients diagnosed with adenocarcinoma of the colon. The pilot study included samples from 6 patients (3 women and 3 men), aged 55 to 72 years (mean 62.5±8.4 years). The tumour was located in the rectum, TNM status was as follows: cT (all patients at stage T3), cN (3 patients – N1, 3 patients – Nx), cM (all patients at stage M0). Average tumor size 4.6±2.5 cm. Normal colon tissue was used as a control. The studies were performed with the consent of the patient and according to the protocol accepted by the Bioethics Committee at the Medical University of Lublin No. KE-0254/12/2018. The material was collected during tumor removal surgery, then transported and stored in RNAlater. In the next step, microRNAs were isolated using the RNeasy Micro Kit (Qiagen). The quality and quantity of isolated RNA was assessed with NanoDrop 2000c followed by Bioanalyzer 2100 (Agilent), for the next step samples with RIN above 7. The microRNA expression profile was then evaluated using the GeneChip™ miRNA 4.0 Array (Applied Biosystems). Results: On the basis of a pilot microarray study, the profile of differentially expressed miRNAs was successfully screened. 1.39% of 36 222 tested genes showed a significant at least twofold increase in expression, while 1.75% showed a significant at least twofold decrease in expression. Three novel, not yet described in literature, miRNAs i.e. miR-3154 (p-value 0.015), miR-3921 (p-value 0.036), and miR-5006 (p-value 0.007) appeared to be involved in colorectal carcinogenesis. Conclusions: The present study suggests that mentioned miRNAs after confirmation on a greater group of patients may be used as diagnostic markers for the detection of early stage colon cancer in the general population. This paper was created as part of the project “The Best of the Best! 4. 0.” implemented under the Operational Programme: Knowledge Education Development 2014-2020 and co-financed by the European Social Fund.

The number of lymph nodes examined as a poor prognosis factor in stage II and stage III colon cancer patients undergoing curative surgery.

3612 Background: The number of lymph nodes (LN) examined is a key factor in determining the stage of colorectal cancer. Over the past 20 years, the examination of fewer than 12 LN has been regarded as a poor prognosis. However, surgical procedures and pathologic examination improvements have increased the number of LN examined. This raised the question of reassessing the best cutoff point for staging colon cancer patients undergoing curative surgery. Methods: We reviewed a total of 3,126 eligible patients with stage II-III colon cancer collected from the Yonsei Cancer Center Registry (YCC) database between 2005 and 2015. As a validation cohort, we used clinicodemographic data from 9,604 patients with stage II-III colon cancer identified by the Netherlands Cancer Registry (NCR) between 2006 and 2015. The hazard ratio (HR) obtained from Cox-proportional regression was used to investigate the effect of LNs' yield on 6-year overall survival (OS). The optimal LN yield was evaluated by analyzing every cutoff from 3 to 165. We used the Kaplan-Meier method to compare the effect of higher vs. lower optimal LN yield on a 6-year OS. Univariate and multivariate Cox regressions were conducted. Results: The proportion of patients with fewer than 12 LN examined dramatically decreased between 2005 and 2015 (17.4% in 2005 vs. 0.6% in 2015, P< 0.001). Based on the 12 LN examined as the conventional cutoff number, there was no significant association between 6-year OS and LN yield in all stages II-III patients (HR = 1.21, P= 0.116; n = 3,126), stage II (HR = 1.39, P= 0.068; n = 1,570), and stage III (HR = 1.18, P= 0.297; n = 1,557) colon cancer. Interestingly, a higher cutoff of 20 LN examined was associated with a significant increase in 6-year OS in all patients (HR = 1.51, P< 0.001 in patients with LN examined less than 20). Multivariate Cox-proportional hazard regression showed a significant decrease in 6-year OS in stage II (HR = 1.39, P= 0.026) and stage III (HR = 1.54, P< 0.001) with less than 20 LN yield. Consistent with the result in the YCC database, less than 20 of LN yield was associated with poorer 6-year OS in stage II-III patients (HR = 1.25, P< 0.001; n = 9,604), stage II (HR = 1.43, P< 0.001; n = 4,689), and stage III (HR = 1.13, P= 0.007; n = 4,915) in the NCR, respectively. Conclusions: Less than 20 LN examined is associated with a poorer prognosis in patients with surgically treated colon cancer, compared to the current cutoff value of 12. Further validation of re-evaluating criteria on the inadequacy of LN retrieval in high-risk stage II colon cancer is warranted.

Indicators of the immune status in patients with chronic wounds depending on the stage of the infectious process and the structure of the wound microbiota

The results of immunophenotyping of peripheral blood leukocytes were analyzed in 105 patients with chronic wounds ( the main group , wound duration more than 3 weeks ) at various stages of the infectious process : colonization (n=39), critical colonization (n=37) and infection (n=29). The comparison group consisted of 22 patients with acute wounds ( wound duration up to 4 days ), in which microorganisms were not detected in the wounds . In the main group , changes in immunological reactivity were revealed in the form of an increase in the relative content of T- lymphocytes and a decrease in NK cells , lower indicators of early activation markers on T- helpers and T- cytotoxic lymphocytes (CD4+/CD38+/CD3+, CD8+/CD38+/CD3+, CD3+/ CD71+) and HLADR on B- lymphocytes , a high level of expression of late markers of T- cell activation (CD3+HLADR+). In the comparison group , the levels of expression of integrins (CD11a, CD11b, CD11c) on neutrophils and lymphocytes , as well as the transferrin receptor (CD71) on neutrophils , monocytes and lymphocytes were higher than in the main group . An increase in the activity of neutrophils in the form of expression of CD11a molecules was revealed with the progression of the infectious process in a chronic wound , which may be an additional diagnostic sign of the transition from the stage of colonization to the stage of critical colonization and infection . The highest values of CD11a and CD11c on neutrophils were recorded in the presence of S. aureus monocultures in chronic wounds , the lowest values were recorded when P. aeruginosa and A. baumannii monocultures were isolated from wounds .

The Novel Effector Ue943 Is Essential for Host Plant Colonization by Ustilago esculenta.

The smut fungus Ustilago esculenta obligately parasitizes Zizania latifolia and induces smut galls at the stem tips of host plants. Previous research identified a putative secreted protein, Ue943, which is required for the biotrophic phase of U. esculenta but not for the saprophytic phase. Here, we studied the role of Ue943 during the infection process. Conserved homologs of Ue943 were found in smut fungi. Ue943 can be secreted by U. esculenta and localized to the biotrophic interface between fungi and plants. It is required at the early stage of colonization. The Ue943 deletion mutant caused reactive oxygen species (ROS) production and callose deposition in the host plant at 1 and 5 days post inoculation, which led to failed colonization. The virulence deficiency was restored by overexpressing gene Ue943 or Ue943:GFP. Transcriptome analysis further showed a series of changes in plant hormones following ROS production when the host plant was exposed to ΔUe943. We hypothesize that Ue943 might be responsible for ROS suppression or avoidance of recognition by the plant immune system. The mechanism underlying Ue943 requires further study to provide more insights into the virulence of smut fungi.

The Effect of RAS/BRAF Mutation Status on Prognosis and Relapse Pattern in Early Stage Colon Cancers.

It is known that the RAS and BRAF mutations are predictive for targeted therapies in treating metastatic colon cancer and negatively affect the prognosis of the disease. However, there are limited studies in early-stage colon cancer about the relationship of this mutational condition with the prognosis and relapse pattern of the disease. In this study, we evaluated the effects of mutational status on the clinical pattern of recurrence and survival in early-stage colon cancer in addition to classical risk factors. Patients with early-stage colon cancer at the first time of diagnosis and developing recurrence or metastasis on following up were included in this study. Patients were divided into two groups according to the at the time of relapse RAS/BRAF mutation status: mutant or non-mutant/wild types. Then, mutation analysis was performed again from the early-stage tissue of the patients if available. The relationship between early-stage mutation status and progression-free survival (PFS), overall survival (OS), and relapse pattern was analyzed. The number of patients with mutant and non-mutations in the early stage was 39 and 40, respectively. Mutant and non-mutant patients with stage 3 disease were similar (69% and 70%, respectively). OS (47.27months vs. 67.53months; p = 0.02) and PFS (25.12 vs. 38.13months; p = 0.049) were statistically significantly lower in mutant patients, respectively. Most patients had distant metastases on both sides at recurrence (61.5% vs. 62.5%, respectively). There was no significant difference between mutant and non-mutant patients regarding distant metastasis and local recurrence rates (p = 0.657). A discordance of 11.4% between early-stage and late-stage tissue mutation status. The presence of mutation in early-stage colon cancer is associated with shorter OS and PFS. The mutational status did not have a significant effect on the recurrence pattern. Because of the discordance of early-stage and late-stage mutational status, it is recommended to perform mutation analysis from tissue at relapse.

The centripetal endoscopic sinus surgery in patients with cystic fibrosis: A preliminary study

ObjectivesThe main aim of this study is to analyze the possible differences between clinical, demographic or genetic characteristics, in Cystic Fibrosis (CF) patients with chronic rhinosinusitis (CRS) with different phenotype. The secondary objective is to describe the possible benefit of surgery with Centripetal Endoscopic Sinus Surgery (CESS). MethodsThe study includes 56 who performed CT scan of the paranasal sinuses. They were divided in 3 group according to phenotype: CRS without Nasal Polyps (NP); CRS with NP; CRS complicated with Mucocele. The clinical symptoms, age, gender, genotype, microbial colonization and pulmonary disease stage were collected and analyzed to assess possible statistically significant differences. Regarding the 7 patients who performed CESS surgery, the number of hospitalizations, intravenous (iv) antibiotic courses, respiratory exacerbations, the FEV1, the Lund-Mackay Score (LMS) and the SNOT 22 were evaluated before and 1 year after surgery. ResultsNo statistically significant differences regarding clinical symptoms between the 3 groups were identified (p > 0.05). Furthermore, there were no differences in age, gender, genotype, microbial colonization and pulmonary disease stage (p > 0.05). Regarding the patients who performed CESS, no significative difference in FEV1 progression was found. A reduction in hospitalization, pulmonary exacerbation and in the number of iv antibiotic courses resulted statistically significant different (p = 0.004; <0.001 and <0.001 respectively). A significant improvement in SNOT-22 and LMS (p < 0.001) was obtained. ConclusionRadiological monitoring of the rhinosinus disease is necessary regardless of the clinical expression of the disease. The presence of CRS with NP complicated by mucocele is frequent and independent of the patient's age and clinical manifestations. An extensive surgical approach could represent the gold standard for patients with CF in consideration of the potential important advantages to perform a total toilet of all the sinuses and nasal cavities and at the same time eliminating a potential microbiological reservoir.

Beauveria bassiana rewires molecular mechanisms related to growth and defense in tomato.

Plant roots can exploit beneficial associations with soil-inhabiting microbes, promoting growth and expanding the immune capacity of the host plant. In this work, we aimed to provide new information on changes occurring in tomato interacting with the beneficial fungus Beauveria bassiana. The tomato leaf proteome revealed perturbed molecular pathways during the establishment of the plant-fungus relationship. In the early stages of colonization (5-7 d), proteins related to defense responses to the fungus were down-regulated and proteins related to calcium transport were up-regulated. At later time points (12-19 d after colonization), up-regulation of molecular pathways linked to protein/amino acid turnover and to biosynthesis of energy compounds suggests beneficial interaction enhancing plant growth and development. At the later stage, the profile of leaf hormones and related compounds was also investigated, highlighting up-regulation of those related to plant growth and defense. Finally, B. bassiana colonization was found to improve plant resistance to Botrytis cinerea, impacting plant oxidative damage. Overall, our findings further expand current knowledge on the possible mechanisms underlying the beneficial role of B. bassiana in tomato plants.

Root colonization of industrial hemp (Cannabis sativa L.) by the endophytic fungi Metarhizium and Pochonia improves growth

Metarhizium is an endophytic, insect pathogenic fungus. Here we investigated the time-course of systemic and rhizospheric colonization by Metarhizium and its influence on the growth of industrial hemp (Cannabis sativa L.). Fungal colonization of hemp root, stem and leaf as well as rhizospheric soil, and agronomic parameters of hemp, were tested in four Metarhizium species with broad- (Metarhizium robertsii, Metarhizium anisopliae, Metarhizium brunneum) and narrow-insect (Metarhizium acridum) host ranges, as well as Pochonia chlamydosporia, a phylogenetically related endophytic fungus that is a nematode pathogen. Root and rhizosphere colonization were found in all Metarhizium species and Pochonia at 10, 20 and 30 days post-inoculation. Pochonia showed greatest root colonization compared to that of all Metarhizium species. Endophytic root colonization by Metarhizium was confirmed by confocal fluorescence microscopy using green fluorescent protein-expressing fungal strains. The genes, cat, mpl and EF1α were tested using a qPCR assay for Metarhizium and hemp. Root colonization by Metarhizium and Pochonia positively influenced shoot length, stem weight and root weight of hemp during the early stages of colonization. Our results suggest the potential for the application of Metarhizium and Pochonia as biocontrol and plant growth promoter agents during hemp colonization.

Colon Cancer Disparities in Stage at Presentation and Time to Surgery for Asian Americans, Native Hawaiians, and Pacific Islanders: A Study with Disaggregated Ethnic Groups.

Vast differences in barriers to care exist among Asian American, Native Hawaiian, and Pacific Islander (AANHPI) groups and may manifest as disparitiesin stage atpresentation and access totreatment. Thus, we characterized AANHPI patients with stage 0-IV colon cancer and examined differences in (1) stage at presentation and (2) time to surgery relative to white patients. We assessed all patients in the National Cancer Database (NCDB) with stage 0-IV colon cancer from 2004 to 2016 who identified as white, Chinese, Japanese, Filipino, Native Hawaiian, Korean, Vietnamese, Laotian, Hmong, Kampuchean, Thai, Asian Indian or Pakistani, and Pacific Islander. Multivariable ordinal logistic regression defined adjusted odds ratios (AORs), with 95% confidence intervals (CI), of (1) patientspresenting withadvanced stage colon cancer and (2) patients with stage 0-III colon cancerreceiving surgery at ≥60days versus 30-59days versus <30days postdiagnosis, adjusting for sociodemographic/clinical factors. Among 694,876 patients, Japanese [AOR1.08 (95% CI 1.01-1.15), p<0.05], Filipino [AOR1.17 (95% CI 1.09-1.25), p<0.001], Korean [AOR1.09 (95% CI 1.01-1.18), p<0.05], Laotian [AOR1.51 (95% CI 1.17-1.95), p<0.01], Kampuchean [AOR1.33 (95% CI 1.04-1.70), p<0.01], Thai [AOR 1.60 (95% CI 1.22-2.10), p=0.001], and Pacific Islander [AOR1.41 (95% CI 1.20-1.67), p<0.001] patients were more likely to present with more advanced colon cancer compared with white patients. Chinese [AOR1.27 (95% CI 1.17-1.38), p<0.001], Japanese [AOR 1.23 (95% CI 1.10-1.37], p<0.001], Filipino [AOR1.36 (95% CI 1.22-1.52), p<0.001], Korean [AOR1.16 (95% CI 1.02-1.32), p<0.05], and Vietnamese [AOR1.55 (95% CI 1.36-1.77), p<0.001] patients were more likely to experience greater time to surgery than white patients. Disparities persisted when comparing among AANHPI subgroups. Our findings reveal key disparities in stage at presentation and time to surgery by race/ethnicity among AANHPI subgroups. Heterogeneity upon disaggregation underscores the importance of examining and addressing access barriers and clinical disparities.

Abstract 2434: Regulation of initiation and establishment of ovarian cancer metastasis by metastasis initiating cells

Abstract Ovarian cancer (OC) is the deadliest gynecologic malignancy with a dismal prognosis worldwide. A key reason for this is that most patients already have extensive metastasis at the time of diagnosis. Therefore, it is metastatic disease that is being treated in the clinic. However, metastasis remains one of the least understood aspects of cancer biology and a better understanding of the mechanisms involved will be helpful in devising more effective therapies. Transcoelomic metastasis is prevalent in ovarian cancer, which involves exfoliation of cancer cells in the primary tumor, floatation and spreading in the peritoneal fluid, followed by attachment, and colonization of the peritoneal organs. The most common site being the omentum. Recent research has indicated that a small percentage of OC cells, called metastasis-initiating cells (MICs) are able to survive at the metastatic site and establish metastases. However, the characteristics of MICs, their productive interactions with the metastatic microenvironment, and how they colonize metastatic sites, remain poorly understood. We attempted to address this issue with a focus on high grade serous OC (HGSOC), the most prevalent and lethal subtype of OC. We used HGSOC cells isolated from patient ascites and seeded them on an organotypic 3D culture model of the surface layers of the omentum to mimic early stage of metastatic colonization. The same cells were injected intraperitoneally in NSG mice to generate patient derived xenografts, representing advanced metastasis. Single cell transcriptomics was performed in both these models to identify the heterogeneity of the patient derived OC cells and the changes in their subpopulation profiles during early and advanced metastasis. Inference of activity scores of gene sets (AUCell), analysis of regulons (SCENIC) and identification of markers (Seurat and CytoTRACE) of the single-cell transcriptomic data helped characterize the MICs. We identified one distinctive population of OC cells with MIC-like phenotype. Utilizing trajectory analysis (Monocle3) we have determined the potentially targetable differentiation trajectories between the MICs and other cancer cells populating the established metastases. Intra-tumoral interactions were also investigated using CellCall to identify targetable ligand-receptor pairs. Elimination of MICs, interference of intra-tumoral communications inducing stemness of MICs, or interruption of their differentiation trajectory paths that help establish the metastases, may be a novel therapeutic opportunity leading to improved outcomes for the OC patients who are diagnosed with metastasis. Citation Format: Ji Wang, Subramanyam Dasari, Chi Zhang, Anirban Kumar Mitra. Regulation of initiation and establishment of ovarian cancer metastasis by metastasis initiating cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2434.

Autolysin-mediated peptidoglycan hydrolysis is required for the surface display of Staphylococcus aureus cell wall-anchored proteins

Peptidoglycan hydrolases, or autolysins, play a critical role in cell wall remodeling and degradation, facilitating bacterial growth, cell division, and cell separation. In Staphylococcus aureus, the so-called "major" autolysin, Atl, has long been associated with host adhesion; however, the molecular basis underlying this phenomenon remains understudied. To investigate, we used the type V glycopeptide antibiotic complestatin, which binds to peptidoglycan and blocks the activity of autolysins, as a chemical probe of autolysin function. We also generated a chromosomally encoded, catalytically inactive variant of the Atl enzyme. Autolysin-mediated peptidoglycan hydrolysis, in particular Atl-mediated daughter cell separation, was shown to be critical for maintaining optimal surface levels of S. aureus cell wall-anchored proteins, including the fibronectin-binding proteins (FnBPs) and protein A (Spa). As such, disrupting autolysin function reduced the affinity of S. aureus for host cell ligands, and negatively impacted early stages of bacterial colonization in a systemic model of S. aureus infection. Phenotypic studies revealed that Spa was sequestered at the septum of complestatin-treated cells, highlighting that autolysins are required to liberate Spa during cell division. In summary, we reveal the hydrolytic activities of autolysins are associated with the surface display of S.aureus cell wall-anchored proteins. We demonstrate that by blocking autolysin function, typeV glycopeptide antibiotics are promising antivirulence agents for the development of strategies to control S. aureus infections.

Ten-Year Recurrence Outcomes in Early Stage and Early Onset Colon Cancer and the Expression Profiles of MicroRNAs and Cancer Stem Cell Markers in These Tumors

Objective: We hypothesized that microRNAs (miRNAs) might be involved in tumor development by critically regulating cancer stem cell (CSC) markers in the early stages of colon cancer (eCC). This study aimed to determine the expression profiles of miRNAs in CSC-positive eCC patients and examine their associations with recurrence. Materials and Methods: We analyzed CD133, LGR5 and SOX2 expression profiles to determine CSC status in 30 eCC specimens. Then, using the results of RT2 miRNA PCR custom arrays, we evaluated the expression profiles of 38 miRNAs in CSC-positive eCC patients. Results: Recurrence occurred in 5 patients within ten years after surgery. We determined down-regulation of miR-125b and up-regulation of miR-135b were significant in CSC-positive eCC patients (p=0.021, p=0.001, respectively). We found that low expression of miR-125b was associated with recurrence in eCC (p=0.0022). Conclusions: We suggest that recurrence might be prevented by increasing the expression of miR-125b in eCC.

Incidence of Disease Recurrence in Patients With Colon and Upper Rectum Adenocarcinoma Stage II and III Receiving Adjuvant Capecitabine Monotherapy: Do Number of Chemotherapy Cycles and Relative Dose Intensity of the Drug Play a Role?

Introduction/BackgroundAdjuvant capecitabine monotherapy is an option for colon and upper rectum adenocarcinoma patients, providing they have stage II disease with an intermediate risk of recurrence, or stage III but they are above 70’s or they have comorbidities. We wanted to examine whether the number of chemotherapy cycles and the relative dose intensity (RDI) of capecitabine monotherapy in the adjuvant setting are affecting disease recurrence. Patients and MethodsWe included patients with completely resected stage II and III colon and upper rectum cancer who received adjuvant capecitabine monotherapy, from 2003 until May 2020. Patients with early relapse, i.e. during chemotherapy or within 6 months after the completion of adjuvant chemotherapy, and those with rectal cancer who received radiotherapy were excluded. Patients were divided into 3 groups based on the number of chemotherapy cycles received and the RDI. Group A included patients with ≤4 cycles of chemotherapy, group B patients with >4 cycles of chemotherapy and RDI ≤80%, and group C patients with >4 cycles of chemotherapy and RDI >80%. Study’s endpoint, was recurrence free survival (RFS). ResultsTwo hundred twenty six patients with stage II and III disease (164 and 62 respectively) were included. Sixteen, 166 and 44 were included in groups A, B and C respectively. After a median follow-up of 41 months, 21 patients (9,3%) had relapsed. Patients belonging to group C were found to have a trend for lower relapse rate compared to patients belonging to group A or group B. ConclusionNumber of adjuvant capecitabine cycles and RDI might play a role in RFS in patients with stage II and III colon and upper rectum adenocarcinoma.

Abstract GS5-07: Estradiol represses anti-tumoral immune response to promote progression of triple-negative breast cancer brain metastases

Abstract Background: Younger women with breast cancer have increased risk of development of brain metastases irrespective of the tumor subtype. We have shown that pre-menopausal levels of 17-β-Estradiol (E2) contributes to the promotion of brain metastases by influencing the tumor microenvironment. E2 promotes brain metastasis (BM) of estrogen receptor negative (ER¯) BC cells by inducing neuroinflammatory ER+ astrocytes in the brain niche to secrete pro-metastatic factors critical for early brain colonization. Ovarieoctomy (OVX) in combination with the aromatase inhibitor (Letrozole) prevented brain colonization of triple negative (TNBC) (ER-PR-HER2-) human xenografts (MDA231BR/NSG) and murine models (E0711/C57Bl6, 4T1/BALBc) through paracrine activation of EGFR and TRKB, pathways involved in increased invasion and early tumor initiation. Yet, the extent to which E2-depletion therapies can decrease progression of established BM in combination with current standard of care for brain metastasis remains unknown. Goal: Current standard of care (SOC) for patients with TNBC brain metastasis includes irradiation (SRS, whole brain) and immunotherapy (PD-1/PDL-1 inhibitors). The goal of this study was to assess how E2-depletion therapies affects brain immune function in the context of SOC for brain metastatic progression of TNBC. Results: To assess whether E2-depletion could decrease BM progression in a model that mimics standard of care for BM, TNBC E0771-GFP-luc cells were injected intracardially in syngeneic ovariectomized (OVX)-female C57Bl6 mice supplemented with pre-menopausal levels of E2. Seven days after injection (when cancer cells have colonized), mice received a single 15Gy dose brain irradiation and were randomized to continue receiving E2, E2 withdrawal (E2WD) or E2WD plus the aromatase-inhibitor letrozole (E2WD+LET). Brain metastatic burden significantly decreased in E2WD and E2WD+Letrozole treated mice as compared to E2-treated mice. Injection of E0711 cells in immunocompromised NSG mice or in the absence of brain irradiation abolished this effect, suggesting that E2-depletion therapies decrease BM progression through boosting radiation-induced anti-tumor immunity. Accordingly, there were no differences in BM progression in E2, E2WD or E2WD+let treated mice in a xenograft model (F2-7 TNBC cells) in NSG mice, even in the presence of brain irradiation. Immune-profiling of brains from OVX+E2, OVX and OVX+Let C57BL6 mice carrying BMs showed dynamic changes in immune populations at early and late stages of brain metastatic colonization. At early stages post brain colonization (3 days post ic injection) E2-treated mice showed a decreased fraction of CD11b+CD45Int CD206+ microglia/CNS macrophages as compared to OVX+LET-treated mice, without significant changes in the fraction of infiltrated lymphocytes, suggesting E2 represses early immunosurveillance through repression of microglia/CNS macrophage activation. At later stages of brain colonization (7 days post ic injection), E2-treated mice showed an increased fraction of proinflammatory microglia and decreased fraction of T and B cells as compared to OVX or OVX+let treated mice. While E2-depletion increased the recruitment of T cells to the brain niche, the fraction of CD279 (PD1+) brain T cells was similar among groups. Ongoing studies assess the efficacy of E2-depletion therapies in combination with brain radiation and PD-1 inhibitors to decrease metastatic burden and improve survival in preclinical models. Conclusion: Our results support the hypothesis that estradiol promotes brain metastatic progression by stimulating an immunosuppressive brain microenvironment. As such, FDA-approved E2-depletion therapies (aromatase inhibitors and selective-estrogen modulators) could be used in combination with brain irradiation and PD-1 inhibitors to promote a more effective anti-tumoral immune response. Citation Format: Diana Cittelly, Maria J. Contreras-Zarate, Karen ALvarez-Eraso, Vesna Tesic, Nicole Tsuji, Leanna Chafee, Sana Karam, D. Ryan Ormond, Peter Kabos. Estradiol represses anti-tumoral immune response to promote progression of triple-negative breast cancer brain metastases [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS5-07.

Exploring the Role of Salicylic Acid in Regulating the Colonization Ability of Bacillus subtilis 26D in Potato Plants and Defense against Phytophthora infestans

Plant colonization by endophytic bacteria is mediated by different biomolecules that cause dynamic changes in gene expression of both bacteria and plant. Phytohormones, in particular, salicylic acid, play a key role in the regulation of endophytic colonization and diversity of bacteria in methaphytobiome. For the first time it was found that salicylic acid influenced motility in biofilms and transcription of the surfactin synthetase gene of the endophytic strain Bacillus subtilis 26D in vitro. Treatment of Solanum tuberosum plants with salicylic acid, along with B. subtilis 26D, increased the number of endophytic cells of bacteria in potato internal tissues and level of transcripts of bacterial surfactin synthetase gene and decreased transcription of plant PR genes on the stage of colonisation with endophytes. Thus, the production of surfactin plays an important role in endophytic colonization of plants, and salicylic acid has an ability to influence this mechanism. Here we firstly show that plants treated with salicylic acid and B. subtilis 26D showed enhanced resistance to the late blight pathogen Phytophthora infestans, which was accompanied by increase in transcriptional activity of plant PR-genes and bacterial surfactin synthetase gene after pathogen inoculation. Therefore, it is suggested that salicylic acid can modulate physiological status of the whole plant–endophyte system and improve biocontrol potential of endophytic strains.

Fibre fermentation and pig faecal microbiota composition are affected by the interaction between sugarcane fibre and (poly)phenols in vitro

We investigated the effects of (poly)phenol-rich sugarcane extract (PRSE), sugarcane fibre (SCFiber), and the combination of them (PRSE + SCFiber) on the gut microbiota and short-chain fatty acids (SCFA) production using in vitro digestion and pig faecal fermentation. Measuring total phenolic content and antioxidant activity through the in vitro digestion stages showed that PRSE + SCFiber increased the delivery of (poly)phenols to the in vitro colonic fermentation stage compared to PRSE alone. The PRSE + SCFiber modulated the faecal microbiota profile by enhancing the relative abundances of Prevotella, Lactobacillus, and Blautia, and reducing the relative abundance of Streptococcus. PRSE + SCFiber also mitigated the inhibitory effects of PRSE on SCFA production. These results suggest that the inclusion of sugarcane fibre with PRSE could increase the availability of phenolic compounds in the colon and modulate the gut microbiota towards a more favourable profile.

Yersinia pestis Δail Mutants Are Not Susceptible to Human Complement Bactericidal Activity in the Flea.

Ail confers serum resistance in humans and is a critical virulence factor of Y. pestis, the causative agent of plague. Here, the contribution of Ail for Y. pestis survival in the flea vector was examined. Rat or human but not mouse sera were bactericidal against a Y. pestis Δail mutant at 28°C in vitro. Complement components deposited rapidly on the Y. pestis surface as measured by immunofluorescent microscopy. Ail reduced the amount of active C3b on the Y. pestis surface. Human sera retained bactericidal activity against a Y. pestis Δail mutant in the presence of mouse sera. However, in the flea vector, the serum protective properties of Ail were not required. Flea colonization studies using murine sera and Y. pestis KIM6+ wild type, a Δail mutant, and the Δail/ail+ control showed no differences in bacterial prevalence or numbers during the early stage of flea colonization. Similarly, flea studies with human blood showed Ail was not required for serum resistance. Finally, a variant of Ail (AilF100V E108_S109insS) from a human serum-sensitive Y. pestis subsp. microtus bv. Caucasica 1146 conferred resistance to human complement when expressed in the Y. pestis KIM6+ Δail mutant. This indicated that Ail activity was somehow blocked, most likely by lipooligosaccharide, in this serum sensitive strain. IMPORTANCE This work contributes to our understanding of how highly virulent Y. pestis evolved from its innocuous enteric predecessor. Among identified virulence factors is the attachment invasion locus protein, Ail, that is required to protect Y. pestis from serum complement in all mammals tested except mice. Murine sera is not bactericidal. In this study, we asked, is bactericidal sera from humans active in Y. pestis colonized fleas? We found it was not. The importance of this observation is that it identifies a protective niche for the growth of serum sensitive and nonsensitive Y. pestis strains.