Characterization of Leishmania donovani MCM4: Expression Patterns and Interaction with PCNA

Events leading to origin firing and fork elongation in eukaryotes involve several proteins which are mostly conserved across the various eukaryotic species. Nuclear DNA replication in trypanosomatids has thus far remained a largely uninvestigated area. While several eukaryotic replication protein orthologs have been annotated, many are missing, suggesting that novel replication mechanisms may apply in this group of organisms. Here, we characterize the expression of Leishmania donovani MCM4, and find that while it broadly resembles other eukaryotes, noteworthy differences exist. MCM4 is constitutively nuclear, signifying that, unlike what is seen in S.cerevisiae, varying subcellular localization of MCM4 is not a mode of replication regulation in Leishmania. Overexpression of MCM4 in Leishmania promastigotes causes progress through S phase faster than usual, implicating a role for MCM4 in the modulation of cell cycle progression. We find for the first time in eukaryotes, an interaction between any of the proteins of the MCM2-7 (MCM4) and PCNA. MCM4 colocalizes with PCNA in S phase cells, in keeping with the MCM2-7 complex being involved not only in replication initiation, but fork elongation as well. Analysis of a LdMCM4 mutant indicates that MCM4 interacts with PCNA via the PIP box motif of MCM4 - perhaps as an integral component of the MCM2-7 complex, although we have no direct evidence that MCM4 harboring a PIP box mutation can still functionally associate with the other members of the MCM2-7 complex- and the PIP box motif is important for cell survival and viability. In Leishmania, MCM4 may possibly help in recruiting PCNA to chromatin, a role assigned to MCM10 in other eukaryotes

Detection of Postcoronary Stent Complication: Utility of 64-Slice Multidetector CT

Coronary stent fracture is a known complication of coronary arterial stent placements. Multiple long-term risks are also associated with drug eluting stents. 64-slice multidetector CT (MDCT) coronary angiography has been shown to detect poststent complications such as instent stenosis, thrombosis, stent migration and stent fractures. We report a case of stent fracture in a patient who underwent RCA stenting with associated RCA perforation and almost complete thrombosis of the RCA and peristent fibrinoid collection. This is a rare case of stent fracture with perforation of the RCA. The paper highlights the role of 64-row multidetector computed tomography (MDCT) in evaluation of such poststent placement complications

Gas chromatography-mass spectroscopic profiling and cytotoxic activity of Riccia billardieri Mont. & nees (Bryophyta: Liverwort)

Liverworts are a highly diverse group of bryophytes containing flavonoids and polyphenols. The significance of liverworts in therapeutic applications has recently been highlighted due to their antiviral and cytotoxic properties. This study has undertaken an effort to identify the phytochemical profiling (total phenolic and flavonoid content) of liverwort (Riccia billardieri) in Rajasthan. A wide range of botanical elements was predicted by gas chromatography-mass spectroscopy, and the resultant profiles were analyzed for potential therapeutic properties against colorectal cancer

Abstract PO5-10-03: A Translational Epidemiologic Approach to Understand Disparities in Triple Negative Breast Cancer: Integrating Germline Genomics, Genetic Ancestry, and Neighborhood Disadvantage

Abstract Background: Triple-negative breast cancer (TNBC) disproportionately affects women of West African ancestry and those living in neighborhood disadvantage (ND). However, these studies were limited in their ability to control for both ancestry and socioeconomic data. To overcome this limitation, we utilized the epidemiologic-genomic infrastructure of the Miami Breast Cancer Disparities (MBCD) study to evaluate the impact of ND on relative risk (RR) of TNBC, independent of West African ancestry. Methods: A prospective cohort of 502 women with breast cancer enrolled in the MBCD study from 2020-2022. Genetic ancestry, median neighborhood-level income quartiles (ND), germline genetic mutations, and tumor characteristics were assessed. Multinomial logistic regression was used to determine the RR between West African ancestry and TNBC (compared to ER+/HER2- and HER2+ disease) after controlling for access to care measures which might impact TNBC distributions and known TNBC risk factors (e.g., age, ND, BRCA 1 mutation, obesity, screening mammography). Results: Of the 502 women, 333 (66.33%) had ER+/HER2- disease, 67 (13.35%) had ER+/HER2+ disease, 22 (4.38%) had ER-/HER2+ disease, and 80 (15.94%) had TNBC. On univariable analysis, the highest West African quartile (RR 3.58 95%CI 1.72-7.42, p< 0.001), a BRCA 1 mutation (RR 7.89 95%CI 2.25-27.64, p=0.001) were associated with a higher RR of TNBC. Conversely, decreasing ND was associated with a lower RR of TNBC (RR 0.42 95%CI 0.21-0.83, p=0.013). On covariate adjusted multivariable analysis, decreasing ND (RR 0.45 95%CI 0.22-0.99, p=0.047) and a BRCA 1 mutation (RR 12.68 95%CI 3.19-50.35, p< 0.0001) were both significantly associated with TNBC compared to ER+/HER2- and HER2+ disease. Conclusions: To our knowledge, this prospective study is the first to evaluate the combined impact of genetic ancestry, germline genomics, and social factors on RR of TNBC. We discovered that ND and BRCA 1 mutations are independent predictors of TNBC, even after accounting for known TNBC risk factors (e.g., West African ancestry). These findings suggest a potential association between ND and TNBC, thus emphasizing the importance of a translational epidemiologic approach to understand TNBC disparities that considers both genomic and non-genomic factors. Table. Adjusted Multinomial Logistic Regression of Patient Genetic Ancestry, Sociodemographic and Tumor Characteristics Predictors of Breast Cancer Subtype Citation Format: Neha Goel, Alexandra Hernandez, Susan Kesmodel, Erin Kobetz, Nipun Merchant, Timothy Rebbeck. A Translational Epidemiologic Approach to Understand Disparities in Triple Negative Breast Cancer: Integrating Germline Genomics, Genetic Ancestry, and Neighborhood Disadvantage [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-10-03

Abstract P3-13-05: Comprehensive analysis of global genetic ancestry and socioeconomic status on breast cancer outcomes

AbstractPurpose: Disparities in breast cancer outcomes have been a long-standing and persistent challenge. Earlier onset, advanced stage at diagnosis, aggressive tumor subtypes [triple negative breast cancer (TNBC)], and worse overall survival (OS) are some of the characteristic features of breast cancer in non-Hispanic Black (NHB) women compared to their non-Hispanic White (NHW) counterparts, denoting one of the most significant examples of racial/ethnic differences in oncology. Given our location in South Florida, gateway to Latin America and the Caribbean, we discovered that these disparities in tumor characteristics and outcomes among NHB and NHW also extend to Hispanic Blacks (HB) compared to Hispanic Whites (HW). Since Hispanics are the second largest ethnic group in the US and have a rich genetic architecture with contributions from European (EU), West African (WA), and Native American (NA) populations, we sought to investigate genomic associations between observed inter and intra-racial/ethnic differences and breast cancer characteristics and outcomes. Methods: Patients with stage I-IV breast cancer were included. Patient socioeconomnic status (SES), tumor and treatment characteristics, and follow-up data were collected for each patient. Genomic analysis was performed on the peripheral blood from a cohort of 309 patients with breast cancer. This breast cancer cohort was comprised of 192 self-reported HW, 12 HB, 46 NHW, 47 NHB, and 12 unknown (declined to report) patients. Leukocyte DNA from each patient was genotyped, generating whole genome single nucleotide polymorphism (SNP) profiles. Global ancestral estimates, using >100,000 SNPs, were calculated against reference samples from EU, WA, NA, and East Asian (EA) ancestral populations. A genomic diversity space was generated via principal component analysis and ADMIXTURE was used to estimate the ancestral proportions among the patients. Results: The genetic structure of individual patient sample revealed a diverse ancestral admixture where average EU, WA, NA, and EA ancestries were 64.5%, 21.8%, 11.2%, and 2.5%, respectively. Multinomial logistic regression revealed a significant association between increasing WA ancestry and aggressive tumor subtypes (ER-/HER2+ and TNBC), p=0.009 and p=0.031, respectively. These findings remained significant when correcting for patient age and tumor stage; however, when adjusting for income, the association between WA ancestry and ER-/HER2+ and TNBC was no longer significant. Kaplan Meier survival curves showed a significant difference in 5-year OS for patients with >70% WA ancestry compared to those with <70% WA ancestry, p=0.023. Conclusions: In this first integrative approach studying genetic ancestry and SES on breast cancer characteristics and outcomes, we found a significant association between increasing WA ancestry and aggressive breast cancer subtypes, even after adjusting for known covariates. More striking, this association was negated when adjusting for income, suggesting potential gene-environment interactions not accounted for by genetic race. We also discovered that Hispanics have a more complex genetic architecture than non-Hispanic patients, which may in-turn drive genetically-associated survival patterns of resiliency with improved survival in HW compared to NHB patients. Furthermore, the OS differences based on quantitative genetic ancestry cut-offs may serve as a future tool in patient prognosis. Collectively, our results show that genetic ancestry and SES influence breast cancer subtypes and survival. This lays a foundation for future studies to investigate complex genomic relationships between race/ethnicity, SES, and breast cancer characteristics and outcomes through the lens of gene-environment interactions.Citation Format: Daniel A Rodriguez, Sina Yadegarynia, J. William Harbour, Nipun B. Merchant, Erin N. Kobetz, Neha Goel. Comprehensive analysis of global genetic ancestry and socioeconomic status on breast cancer outcomes [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-13-05

ZIP Code to Genomic Code: Neighborhood Disadvantage, Aggressive Breast Cancer Biology, and Breast Cancer Outcomes

To determine the association between objective (geospatial) and subjective (perceived) measures of neighborhood disadvantage (ND) and aggressive breast cancer (BCa) tumor biology, defined using validated social adversity-associated transcription factor (TF) activity and clinical outcomes. ND is associated with shorter BCa recurrence-free survival (RFS), independent of individual, tumor, and treatment characteristics, suggesting potential unaccounted biological mechanisms by which ND influences RFS. We quantified TF-binding motif prevalence within promoters of differentially expressed genes for 147 tissue samples prospectively collected on protocol. Covariate-adjusted multivariable regression analyzed objective and subjective ND scores with 5 validated TFs of social adversity and aggressive biology-pro-inflammatory activity (NF-kB, AP-1), sympathetic nervous system (SNS) activity (CREB), and protective cellular responses (IRF, STAT). To clinically validate these TFs as prognostic biomarkers of aggressive biology, logistic regression and multivariable Cox proportional-hazards models analyzed their association with Oncotype DX scores and RFS, respectively. Increasing objective ND was associated with aggressive tumor biology (up-regulated NF-kB, AP-1, down-regulated IRF, STAT) and SNS activation (up-regulated CREB). Increasing subjective ND (e.g., threat to safety), was associated with up-regulated NF-kB and CREB and down-regulated IRF. These TF patterns were associated with high-risk Oncotype DX scores and shorter RFS. In the largest human social genomics study, objective and subjective ND were significantly associated with TFs of aggressive biology and SNS activation. These TFs also correlated with worse clinical outcomes, implicating SNS activation as one potential mechanism behind ND survival disparities. These findings remain to be validated in a national cohort

Translational Epidemiology: An Integrative Approach to Determine the Interplay Between Genetic Ancestry and Neighborhood Socioeconomic Status on Triple Negative Breast Cancer.

To investigate the impact of global and local genetic ancestry and neighborhood socioeconomic status (nSES), on breast cancer (BC) subtype, and gene expression. Higher rates of aggressive BC subtypes [triple negative breast cancer (TNBC)] and worse overall BC survival are seen in black women [Hispanic Black (HB) and non-Hispanic Black (NHB)] and women from low nSES. However, the complex relationship between genetic ancestry, nSES, and BC subtype etiology remains unknown. Genomic analysis was performed on the peripheral blood from a cohort of 308 stage I to IV non-Hispanic White (NHW), Hispanic White (HW), HB, and NHB women with BC. Patient and tumor characteristics were collected. Global and local ancestral estimates were calculated. Multinomial logistic regression was performed to determine associations between age, stage, genetic ancestry, and nSES on rates of TNBC compared to estrogen receptor (ER+)/epidermal growth factor receptor 2 (HER2-), ER+/HER2+, and ER-/HER2+ disease. Among 308 women, we identified a significant association between increasing West African (WA) ancestry and odds of TNBC [odds ratio (OR): 1.06, 95% confidence interval (95% CI): 1.001-1.126, P =0.046] as well as an inverse relationship between higher nSES and TNBC (OR: 0.343, 95% CI: 0.151-0.781, P =0.011). WA ancestry remained significantly associated with TNBC when adjusting for patient age and tumor stage, but not when adjusting for nSES (OR: 1.049, 95% CI: -0.987-1.116, P =0.120). Local ancestry analysis, however, still revealed nSES-independent enriched WA ancestral segment centered at χ 2 =42004914 ( p =3.70×10 -5 ) in patients with TNBC. In this translational epidemiologic study of genetic ancestry and nSES on BC subtype, we discovered associations between increasing WA ancestry, low nSES, and higher rates of TNBC compared to other BC subtypes. Moreover, on admixture mapping, specific chromosomal segments were associated with WA ancestry and TNBC, independent of nSES. However, on multinomial logistic regression adjusting for WA ancestry, women from low nSES were more likely to have TNBC, independent of genetic ancestry. These findings highlight the complex nature of TNBC and the importance of studying potential gene-environment interactions as drivers of TNBC. Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.</CopyrightInformation

Overcoming disparities: Multidisciplinary breast cancer care at a public safety net hospital

Public safety net hospitals (SNH) serve a disparate patient population; however, little is known about long-term oncologic outcomes of patients receiving care at these facilities. This study is the first to examine overall survival (OS) and the initiation of treatment in breast cancer patients treated at a SNH. Patients presenting to a SNH with stage I-IV breast cancer from 2005 to 2017 were identified from the local tumor registry. The hospital has a weekly breast tumor board and a multidisciplinary approach to breast cancer care. Kaplan-Meier survival analysis was performed to identify patient, tumor, and treatment characteristics associated with OS. Factors with a p < 0.1 were included in the Cox proportional hazards model. 2709 breast cancer patients were evaluated from 2005 to 2017. The patient demographics, tumor characteristics, and treatments received were analyzed. Five-year OS was 78.4% (93.9%, 87.4%, 70.9%, and 23.5% for stages I, II, III, and IV, respectively). On multivariable analysis, higher stage, age > 70 years, higher grade, and non-Hispanic ethnicity were associated with worse OS. Patients receiving surgery (HR = 0.33, p < 0.0001), chemotherapy (HR = 0.71, p = 0.006), and endocrine therapy (HR = 0.61, p < 0.0001) had better OS compared to those who did not receive these treatments. Despite serving a vulnerable minority population that is largely poor, uninsured, and presenting with more advanced disease, OS at our SNH approaches national averages. This novel finding indicates that in the setting of multidisciplinary cancer care and with appropriate initiation of treatment, SNHs can overcome socioeconomic barriers to achieve equitable outcomes in breast cancer care