Dose Of Tamoxifen Research Articles

Drug exposure and risk factors of maculopathy in tamoxifen users

Tamoxifen, a pivotal therapy for hormone receptor-positive breast cancer, is known for its efficacy in reducing breast cancer recurrence and mortality. However, concerns about potential ocular complications, particularly maculopathy, have emerged. This study aims to investigate the risk and associated factors of diverse macular conditions in tamoxifen users, considering drug exposure, demographics, and systemic diseases. A nationwide cohort of tamoxifen users, comprised of 14,267 tamoxifen users, was analyzed using the health insurance review and assessment database in South Korea. Demographic and clinical characteristics were examined, and the cumulative incidence of macular diseases was stratified by age and cumulative tamoxifen dosage. We conducted logistic regression analysis to identify potential risk factors among clinical variables such as age, sex, indications for tamoxifen use, and systemic diseases associated with various macular conditions. Additionally, Cox proportional hazard models were used to determine the baseline clinical characteristics predictive of these macular conditions, with subsequent calculation of hazard ratios. Cumulative incidences of overall macular diseases, other maculopathy excluding common macular diseases, and macular edema were 26.4, 11.4, and 6.5%, respectively. The incidence of various macular conditions increased with age and the cumulative tamoxifen dose. Age, cumulative dose group, and liver diseases demonstrated significant associations with overall macular diseases and maculopathy excluding common macular diseases in multivariate logistic regression analyses (all P < 0.05). Furthermore, age emerged as significant predictive factors of maculopathy in Cox proportional hazard models. Tamoxifen-induced maculopathy poses a concern for prescribing physicians and ophthalmologists, and this study provides valuable insights into its risk and risk factors. This study may contribute to evidence-based guidelines for tamoxifen maculopathy screening, emphasizing the importance of considering age, cumulative dose, and liver diseases for recommendation on screening timing and frequency.

The Influence of CYP2D6 Gene Variants on Tamoxifen Therapy in Breast Cancer Patients in the Asian Region

reast cancer is one of the most prevalent cancers in society, especially among women. Tamoxifen is often used as a first-line therapy for breast cancer and reduces the risk of recurrence in ER+ breast cancer. However, the response to treatment varies due to genetic variability resulting from polymorphisms in the DNA encoding drug-metabolism enzymes, including the CYP2D6 gene. This literature review aimed to evaluate the impact of CYP2D6 gene variants on the effectiveness of tamoxifen in breast cancer treatment. A literature search was conducted through PubMed, Google Scholar, and BMC Cancer using relevant keywords. The selected articles were no more than ten years old (2014-2024), with criteria for inclusion and exclusion. The review of articles from various research journals found that in the Asian region, the CYP2D6 gene variant allele *10 was most frequently seen, resulting in Intermediate Metabolism (IM) in tamoxifen therapy. Patients with IM metabolism tend to have suboptimal therapeutic responses and require tamoxifen dose adjustments.Conversely, patients with Normal Metabolism (NM/EM) tend to have better therapeutic responses. Genetic variability in the CYP2D6 gene affects the activity of the CYP2D6 enzyme, which functions to convert tamoxifen into its active form, Endoxifen. Some individuals may have low (Poor Metabolizer), Intermediate (Intermediate Metabolizer), Normal (Extensive Metabolizer), or even high (Ultra-rapid Metabolizer) enzyme activity. Therefore, adjusting tamoxifen therapy based on patient genetic information is essential for optimal treatment, especially in Asia, where the CYP2D6 gene variant allele *10 is most commonly found, resulting in IM metabolism

Endoxifen Concentration is Associated with Recurrence-Free Survival in Hormone-Sensitive Breast Cancer Patients.

The metabolism of tamoxifen is influenced by various cytochrome p450 enzymes, including CYP2D6 and CYP2C19, leading to variations in the levels of endoxifen, even with the same tamoxifen dosage. However, the clinical significance of endoxifen on the prognosis of breast cancer patients remains controversial. This study aimed to elucidate the relevance of endoxifen level to recurrence-free survival censored with tamoxifen discontinuation (RFSt), representing the RFS for tamoxifen itself, of breast cancer patients and determine a suitable cutoff for prognostication. The study included 478 breast cancer patients, and tamoxifen and its metabolites, including endoxifen, were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). An optimal cutoff was determined with maximally selected rank statistics. Survival analysis and Cox regression were conducted based on this cutoff. An endoxifen level of 21.00 ng/mL was the optimal cutoff for prognostication. Survival analysis revealed a statistically significant difference in RFSt between the low endoxifen group (≤ 21.00 ng/mL) and high endoxifen group (> 21.00 ng/mL) (log-rank test, p=0.032). The 10-year probability of RFSt was 83.2% (95% CI, 77.0-89.9%) and 88.3% (95% CI, 83.3-93.5%) in the low and high endoxifen groups, respectively. Multivariable Cox proportional hazards regression indicated endoxifen concentration as a significant factor affecting prognosis, which was adjusted with other clinical characteristics. Endoxifen could serve as a marker for appropriate tamoxifen treatment, and an endoxifen cutoff of 21.00 ng/mL could be advantageous in prognostication. Based on this cutoff, therapeutic drug monitoring would benefit patients displaying a suboptimal concentration.

Acute pancreatitis secondary to tamoxifen-induced hypertriglyceridemia: A systematic review.

e24105 Background: Tamoxifen can cause paradoxical effects on lipid metabolism and increase triglyceride levels. Acute pancreatitis (AP) can culminate in increased severity and morbidity. A multitude of secondary etiologies may lead to hypertriglyceridemia (HTG), including alcohol, pregnancy, diabetes mellitus, or medications. Tamoxifen is known to cause HTG, but AP as a sequel to this complication remains exceedingly rare. Methods: We performed a systematic search of MEDLINE, Cochrane, Embase, and Google Scholar by using MeSH terms and keywords "tamoxifen," "acute pancreatitis," and "hypertriglyceridemia" from tamoxifen approval in 1977 to December 2023. A total of 26 cases were identified. The diagnosis of AP was established on meeting two of the three Revised Atlanta Classification criteria. Results: A total of 17 case reports fulfilled our inclusion criteria. The mean age of included patients was 35.84 ± 5.99 years. Clinical presentation was mainly related to vomiting (65%), abdominal pain (59%), nausea (47%), and epigastric discomfort (18%). HTG (55%), diabetes mellitus (27%), and hypertension (18%) were major comorbid conditions. The mean onset delay was 11.81 ± 14.75 months, and the tamoxifen dose was 20 mg per day. AP was categorized into mild (35%), moderate (35%), or severe (30%) forms. Treatment mainly consisted of conservative measures, but intravenous insulin (24%) and plasmapheresis (6%) were used in severe cases. The overall mortality rate was 6%. Conclusions: Tamoxifen-induced hypertriglyceridemic pancreatitis is a potential complication of tamoxifen therapy. The findings underscore the need for regular monitoring of serum lipids in these patient patients, especially those with pre-existing HTG or other comorbid conditions that increase their risk of developing hypertriglyceridemic pancreatitis. By implementing these recommendations, clinicians can help reduce morbidity and mortality associated with this condition. [Table: see text]

Impact of CYP2D6 polymorphisms on adverse events in patients with breast cancer treated with tamoxifen: Insights from an early dose escalation trial in CYP2D6 poor metabolizers.

547 Background: Tamoxifen is widely used in treating hormone receptor-positive breast cancer. It is primarily metabolized by the CYP2D6 enzyme to yield active metabolites. However, CYP2D6 polymorphisms have been associated with a differential response to tamoxifen. In a clinical trial involving an early dose escalation of tamoxifen in poor metabolizers, we found endoxifen concentration levels similar to those of patients with extensive phenotype, and no long-term survival differences among CYP2D6 phenotypes. However, the impact of that dose escalation on side effect incidence was not addressed. Methods: In this study, we analyzed the incidence of specific side effects - osteoarticular pain, hot flashes, asthenia, and uterine alterations - in 86 breast cancer patients, differentiated by their CYP2D6 phenotype estimated according to the Clinical Pharmacogenetics Implementation Consortium. In poor metabolizers, the tamoxifen standard dose of 20 mg/day was escalated to 40 mg/day and 60 mg/day for 4 months each, and then treated with 20 mg/day until completing the treatment. Kaplan-Meier analysis and Cox proportional hazards regression model were employed to assess the relationship between the CYP2D6 phenotype and the incidence of these side effects. Results: The median follow-up time was 139.5 months. The analyses revealed that only uterine changes showed significant differences between CYP2D6 phenotypes, with a lower incidence in extensive metabolizers (P-value &lt; 0.001 in Kaplan-Meier; HR in Cox of 0.195, 95% CI 0.073 - 0.521, P = 0.001). This finding persisted after adjustment for the covariates tumor grade, size, nodal status, chemotherapy, and radiotherapy in multivariate Cox regression (HR 0.098, 95% CI 0.020 - 0.466, P = 0.004). Selection of a subgroup through Propensity Score Matching (21 vs 21) corroborated these results. The spectrum of uterine changes and pathologies included endometrial hyperplasia, polyps, adenocarcinoma, myometrial or endometrial thickening, and the presence of multiple myomas. Conclusions: Our study indicates that an early increase in tamoxifen dose in poor metabolizer patients according to CYP2D6 polymorphisms may significantly affect the incidence of uterine changes, but not the incidence of osteoarticular pain, hot flashes, or asthenia. Clinical trial information: 2007-002942-40/ES .

#2069 Elucidating the function of novel Arg1+/Clec4d+ scar-associated monocyte-derived macrophage population in driving fibrosis in kidney disease models

Abstract Background and Aims Fibrosis is the final common pathway in all progressive kidney disease. Macrophages are a major myeloid cell component of the renal mononuclear phagocyte system, with roles in defence against infection, renal injury, and repair. Using single-cell RNA sequencing, we identified a novel myeloid cell subset exclusively present in acute injury of the unilateral ureteric obstruction (UUO) model of kidney fibrosis. This population transcriptomically aligns to monocytes but is enriched for both Arginase-1 (Arg1) and the C-type lectin 4d (Clec4d) and a large number of pro-inflammatory and pro-fibrotic genes. We hypothesise that this novel Arg1+/Clec4d+ population contributes to fibrosis deposition in progressive kidney disease. Methods Monocyte-macrophage populations were characterised in different pre-clinical models; UUO, unilateral ischaemic reperfusion injury (uIRI) and subtotal nephrectomy with flow cytometry. Arg1+/Clec4d+ cells were identified by RT-qPCR, flow cytometry, and immunofluorescence. The origin and consequence of Arg1 deletion in monocytes on renal fibrosis was determined by utilising Ccr2-ERT2-TdTomato and Ccr2-ERT2-TdTomato; Arg1 fl/fl mice, respectively. Results The presence of the Arg1+/Clec4d+ cells was validated in the UUO, uIRI and subtotal nephrectomy models of kidney injury. Analysis of intra-renal inflammation revealed CD45+CD11b+Arg1+ cells persisted and increased in number across 7 days. Post-injury, Arg1+ cells were confirmed to be Clec4dhi. To confirm that Arg1+/Clec4d+ cells were derived from monocytes (Ccr2+), we administered tamoxifen to Ccr2CreERT2-TdTomato mice under a single or multiple-dose regimen following UUO surgery. At day 7 post-injury, ∼50% and ∼90% of the Arg1+ cells were TdTomato+ following a single or multiple doses of tamoxifen, respectively, suggesting that these cells are primarily monocyte derived. Moreover, the Arg1+/Clec4d+ cells were found to localise to areas of scarring (Fig. 1). To investigate the therapeutic potential of targeting Clec4d+ expressed on the Arg1+/Clec4d+ macrophages, mice underwent UUO surgery and given multiple doses of a Clec4d-neutralising antibody. A decrease in Arg1 and fibrosis-related gene expression was evident by day 7 post-injury. To understand the role of increased Arg1 expression in the cells we generated Ccr2-ERT2-TdTomato; Arg1 fl/fl mice. These mice had as expected a reduced Arg1 expression in the Ccr2+ population and metabolic profiling by SCENITH of the tissue monocytes revealed that the loss of Arg1 in the cells reduced their glucose dependence. The loss of Arg1 in these cells reduced Havcr1 gene expression in the kidney. Conclusion As fibrosis is a pathological process that can affect any organ, the work included here, in addition to the proposed future studies, has the potential to develop novel therapeutics that limit fibrosis and enhance repair to halt the progression of disease in CKD.

Breast Articles From 2023: Informing Practice Across the Continuum of Care.

With new investigations and clinical trials in breast oncology reported every year, it is critical that surgeons be aware of advances and insights into the evolving care paradigms and treatments available to their patients. This article highlights five publications found to be particularly impactful this past year. These articles report on efforts to select the minimal effective dose of tamoxifen for prevention, to challenge the existing age-based screening guidelines as they relate to race and ethnicity, to refine axillary management treatment standards, to optimize systemic therapy in multidisciplinary care settings, and to reduce the burden of breast cancer-related lymphedema after treatment. Taken together, these efforts have an impact on all facets of the continuum of care from prevention and screening through treatment and survivorship.

Abstract TC-01: Baby-TAM Impact on disease progression

Abstract Professor Hall will have reviewed his studies on the impact of lower doses of tamoxifen on changes in breast density, an important risk factor. Here I will review the work of Professor Decensi’s team on the ability of 5mg/d of tamoxifen (baby-Tam) on the progression rate of DCIS (69%) and other intraepithelial lesions (11% LCIS, 20% atypical ductal hyperplasia). This trial involved 500 pre- and postmenopausal women randomized equally between baby-Tam and placebo with a 9.7 year median follow up. All breast cancer progression (invasive (77%) and DCIS (23%)) was reduced by 42% (25 vs 41 events, P = 0.03) and contralateral tumours by 64% (6 vs 16 events, P = 0.025). No significant increase was seen in any side effect (Table). I will also briefly discuss their new award for a project to compare baby Tam to baby exemestane in a randomized trial in a similar population as above, initially for side effects, but also subsequently for efficacy. Professor Hall will have reviewed his studies on the impact of lower doses of tamoxifen on changes in breast density, an important risk factor. Here I will review the work of Professor Decensi’s team on the ability of 5mg/d of tamoxifen (baby-Tam) on the progression rate of DCIS (69%) and other intraepithelial lesions (11% LCIS, 20% atypical ductal hyperplasia). This trial involved 500 pre- and postmenopausal women randomized equally between baby-Tam and placebo with a 9.7 year median follow up. All breast cancer progression (invasive (77%) and DCIS (23%)) was reduced by 42% (25 vs 41 events, P = 0.03) and contralateral tumours by 64% (6 vs 16 events, P = 0.025). No significant increase was seen in any side effect (Table). I will also briefly discuss their new award for a project to compare baby Tam to baby exemestane in a randomized trial in a similar population as above, initially for side effects, but also subsequently for efficacy. Citation Format: J. Cuzick, P. Hall. Baby-TAM Impact on disease progression [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 TC-01.

Hypothesizing the Green Synthesis of Tamoxifen Loaded Magnetic Nanoparticles for the Treatment of Breast Cancer.

Breast cancer is the second leading cause of death all over the world and is not only limited to females but also affects males. For estrogen receptor-positive breast cancer, tamoxifen has been considered the gold-line therapy for many decades. However, due to the side effects associated with the use of tamoxifen, its use is only limited to individuals in high-risk groups and limits its clinical application to moderate and/or lower-risk groups. Thus, there is a necessity to decrease the dose of tamoxifen, which can be achieved by targeting the drug to breast cancer cells and limiting its absorption to other body parts. Artificial antioxidants used in the formulation preparation are assumed to upsurge the risk of cancer and liver damage in humans. The need of the hour is to explore bioefficient antioxidants from natural plant sources as they are safer and additionally possess antiviral, anti-inflammatory, and anticancer properties. The objective of this hypothesis is to prepare tamoxifen-loaded PEGylated NiO nanoparticles using green chemistry, tumbling the toxic effects of the conventional method of synthesis for targeted delivery to breast cancer cells. The significance of the work is to hypothesize a green method for the synthesis of NiO nanoparticles that are eco-friendly, cost-effective, decrease multidrug resistance, and can be used for targeted therapy. Garlic extract contains an organosulfur compound (Allicin) which has drug-metabolizing, anti-oxidant, and tumour growth inhibition effects. In breast cancer, allicin sensitizes estrogen receptors, increasing the anticancer efficacy of tamoxifen and reducing offsite toxicity. Thus, this garlic extract would act as a reducing agent and a capping agent. The use of nickel salt can help in targeted delivery to breast cancer cells and, in turn, reduces drug toxicity in different organs. This novel strategy may aim for cancer management with less toxic agents acting as an apt therapeutic modality.

Distinct Treatment Outcomes between MVID Patient-Modeled Mice Suggest Epithelial Cell Maturation Is Influenced by MYO5B Functional State

Background and aims: Microvillus inclusion disease (MVID) is a devastating congenital diarrhea and malnutrition disorder caused by different point mutations in Myosin Vb (MYO5B). Specific genotype-dependent epithelial phenotypes or treatment options have not been fully investigated. Using tamoxifen-inducible epithelial-specific MYO5B-deficient (Myo5bΔIEC) mice, we have reported that MYO5B loss disrupts progenitor cell differentiation and that Lyso-Phosphatidic Acid (LPA) signaling and Notch inhibition can ameliorate the differentiation defects. We recently generated another MVID patient-modeled mouse strain, Vil1-CreERT2;Myo5bflox/G519R (Myo5b(G519R)). This study compared the epithelial pathophysiology and the effects of drug treatment between Myo5b(G519R) and Myo5bΔIEC mice. Methods: The MVID model mice and littermate controls received a single dose of tamoxifen, and their intestinal tissues were harvested on day 4 post-tamoxifen. For treatment: the small chemical LPAR5 agonist, Compound-1, or vehicle were given intraperitoneally once a day. Another set of mice received the Notch2-targeted inhibitor, Nirogacestat, on days 1 and 3. Digital image analysis scripts were developed for segmentation of immunostained tissues. Staining intensities and localization (membrane vs. cytoplasm) of markers were assessed in &gt;300,000 epithelial cells per section. Results: Epithelial transcriptional signatures were analyzed by RNA-sequencing of enteroids generated from jejunal crypts of Myo5b(G519R) and Myo5bΔIEC mice. Enteroids from both mice showed significant upregulation of Notch signaling mediators and the downregulation of tuft cell markers and mitochondrial metabolic genes compared to control enteroids. Immunostaining of tissue sections consistently demonstrated that functional Myo5b loss decreases tuft cell numbers and mitochondrial densities in crypt and villus epithelial cells. In the vehicle treated MVID mouse tissues, sodium transporters of enterocytes, such as Na+/H+ exchanger (NHE)3 and Na+-dependent glucose transporter (SGLT)1, were mislocalized from the apical membrane and colocalized with lysosomal markers similar to what is observed in MVID patient tissues. Compound-1 treatment increased the apical localization of NHE3 and SGLT1 both in Myo5b(G519R) and Myo5bΔIEC mouse small intestines, whereas Nirogacestat improved localizations only in Myo5bΔIEC but not Myo5b(G519R) mouse tissues. Conclusions: Functional MYO5B loss, caused by the point mutation at G519R or total knockout directly disrupts Notch signaling and energy metabolic pathways in the epithelial cells, resulting in differentiation defects and malnutrition. The distinct treatment effcacies between the two MVID mouse models suggest that the total loss and impaired function of MYO5B differentially affect epithelial cell functions. NIH R01DK128190, RC2DK118640. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Cancer associated fibroblasts modulate the cytotoxicity of anti-cancer drugs in breast cancer: An in vitro study.

Tumour microenvironment (TME) contributes to resistance to anti-cancer drugs through multiple mechanisms including secretion of pro-survival factors by cancer associated fibroblasts (CAFs). In this study, we determined the chemotherapy resistance producing potential of CAFs in molecular subtypes of breast cancer. The CAFs were isolated from fresh lumpectomy/mastectomy specimens of different molecular subtypes of breast cancer. The CAFs were cultured and secretome was collected from each breast cancer subtype. Breast cancer cell lines MCF-7, SK-BR3, MDA-MB-231, and MDA-MB-468 were treated with different doses of tamoxifen, trastuzumab, cisplatin, and doxorubicin alone respectively and in combination with secretome of CAFs from respective subtypes. MTT assay was done to check cell death after drug treatment. Liquid chromatography-mass spectrometry (LCMS) analysis of CAF secretome was also done. MTT assay showed that anti-cancer drugs alone had growth inhibitory effect on the cancer cells however, presence of CAF secretome reduced the anti-cancer effect of the drugs. Resistant to drugs in the presence of secretome, was determined by increased cell viability i.e., MCF-7, 51.02% to 63.02%; SK-BR-3, 34.22% to 44.88%; MDA-MB-231, 52.59% to 78.63%; and MDA-MB-468, 48.92% to 55.08%. LCMS analysis of the secretome showed the differential abundance of CAFs secreted proteins across breast cancer subtypes. The treatment of breast cancer cell lines with anti-cancer drugs in combination with secretome isolated from molecular subtype specific CAFs, reduced the cytotoxic effect of the drugs. In addition, LCMS data also highlighted different composition of secreted proteins from different breast cancer associated fibroblasts. Thus, TME has heterogenous population of CAFs across the breast cancer subtypes and in vitro experiments highlight their contribution to chemotherapy resistance which needs further validation.

Tamoxifen Dose De-Escalation: An Effective Strategy for Reducing Adverse Effects?

Tamoxifen, a cornerstone in the adjuvant treatment of estrogen receptor-positive breast cancer, significantly reduces breast cancer recurrence and breast cancer mortality; however, its standard adjuvant dose of 20 mg daily presents challenges due to a broad spectrum of adverse effects, contributing to high discontinuation rates. Dose reductions of tamoxifen might be an option to reduce treatment-related toxicity, but large randomized controlled trials investigating the tolerability and, more importantly, efficacy of low-dose tamoxifen in the adjuvant setting are lacking. We conducted an extensive literature search to explore evidence on the tolerability and clinical efficacy of reduced doses of tamoxifen. In this review, we discuss two important topics regarding low-dose tamoxifen: (1) the incidence of adverse effects and quality of life among women using low-dose tamoxifen; and (2) the clinical efficacy of low-dose tamoxifen examined in the preventive setting and evaluated through the measurement of several efficacy derivatives. Moreover, practical tools for tamoxifen dose reductions in the adjuvant setting are provided and further research to establish optimal dosing strategies for individual patients are discussed.

Integrative Bioinformatics Analysis Reveals Potential Target Genes and PTEN Signaling in Breast Cancer and Effect of Zingiber officinale (Ginger) and Allium sativum (Garlic) extract on It.

Breast cancer is the most common type of cancer in women. The construction of a competing gene network is an important step in the identification of the role of hub genes in breast cancers. In the current research, we used a number of bioinformatics tools to construct this network in breast cancer and investigated the combined effect of garlic and ginger on mice model of breast cancer. We chose female mice weighing 18-20 g that were divided into 7 groups including; the cancer group receiving normal saline, different doses of ginger extract (100 and 500 mg/kg), different doses of garlic (50 and 100 mg/kg), tamoxifen (10 mg/ kg) and simultaneous garlic (100 mg/kg) and ginger (500 mg/kg) for 3 weeks intraperitoneal. Then we anesthetized the mice, isolated the tumor, and determined its size. Glutathione reductase and peroxidase levels and HER2, PTEN, and Cullin3 genes expression were measured. We identified 20 hub genes for breast cancer. In animal phase we found that tumor size in all mice receiving garlic and ginger showed a significant decrease compared to the control. Glutathione reductase showed a significant increase in all groups, especially in ginger 500 and combined groups. Glutathione peroxidase increased almost in all groups, especially in ginger 500. Expression of HER2 decreased in all treated groups. Expression of PTEN increased just in the combined group. Taken together, we introduce a number of novel promising diagnostic biomarkers for breast cancer. The use of garlic and ginger in the treatment of cancer can be useful. This action is probably through the antioxidant mechanism, and regulation of the expression of cancer related genes such as PTEN.

A4 DNA HYPOMETHYLATION INHIBITS COLITIS-ASSOCIATED CANCER

Abstract Background Colorectal cancer is the second leading cause of cancer death in Canada. A major risk factor for the development of colorectal cancer is chronic inflammation leading to colitis-associated cancer (CAC). We previously described a CAC mouse model in which tumors arise from DCLK1+ cells following loss of the tumor suppressor adenomatous polyposis coli (APC) and induction of colitis. Interestingly, both colitis and CAC are associated with DNA methylation changes that lead to altered gene expression. Moreover, inhibition of DNA methylation has recently been shown to lead to a viral mimicry response. The effects of DNA methylation on colonic tumorigenesis, however, is not known. Aims Thus, we aim to investigate whether inhibition of DNA methylation leads to a viral mimicry response that inhibits colitis-associated tumorigenesis. Methods We first examined the effects of DNA hypomethylation on CAC, by crossing Dclk1-CreERT2/Apcf/f mice to Dnmt1f/f mice which allowed for knock-out of the DNA methyltransferase enzyme DNMT1 in DCLK1+ cells. Dclk1/Apcf/f/Dnmt1f/f and Dclk1/Apcf/f (control group) mice were administered three doses of tamoxifen followed by 2.5% dextran sodium sulfate (DSS) for five days to induce colitis. Fourteen weeks later, we assessed colonic tumor number and size. In a separate cohort of Dclk1/Apcf/f mice treated with DSS, we compared colonic tumor number in mice treated with six doses of 5-AZA-2’-deoxycytidine (5-AZA) versus vehicle. The effects of 5-AZA and DSS on DNA methylation were assessed using the Infinium Mouse Methylation BeadChip Array on colonic epithelial cells isolated from mice treated with vehicle versus 5-AZA in the presence or absence of colitis. RNA expression of viral transposable elements and type I interferon response related genes were measured as a readout of a viral mimicry response. Lastly, we investigated the mechanism by which DNA hypomethylation affects tumorigenesis by crossing Dclk1/Apcf/f/Dnmt1f/f mice to MAVS knockout mice and examining tumor number following tamoxifen and DSS administration as above. Results Deletion of DNMT1 in DCLK1+ cells or treatment with 5-AZA significantly decreased colonic tumor number and size. Treatment with 5-AZA or DNMT1 loss led to DNA hypomethylation and subsequent upregulation of endogenous retroviral expression. Both 5-AZA treatment and DNMT1 knockout in DCLK1+ cells led to increased expression of type I interferon response genes. Knockout of the type I interferon response related gene, MAVS, reversed the anti-tumor effect observed with DNMT1 loss. Conclusions Our findings demonstrate that DNA hypomethylation by 5-AZA or loss of DNMT1 reduces colitis-associated tumorigenesis through activation of a viral mimicry response. Funding Agencies CAG, CIHRCancer Research Society, Canada Foundation for Innovation, Lawson Health Research Institute

Assessing effects of tamoxifen on tolerance, dependence, and glutamate and glutamine levels in frontal cortex and hippocampus in chronic morphine treatment

Tamoxifen has been shown to reduce glutamate release from presynaptic glutamatergic nerves and reverse tolerance to morphine-induced respiratory depression. Changes in glutamatergic neurotransmission in the central nervous system contribute to morphine tolerance, dependence, and withdrawal. This study, therefore, evaluated effects of tamoxifen on development of analgesic tolerance and dependence, and brain glutamate and glutamine levels in chronic morphine administration. Mice implanted with placebo or morphine pellets were injected with tamoxifen (0.6–2 mg/kg) or vehicle twice daily for 3 days. Nociceptive response was evaluated in the hot plate and tail immersion tests, 4, 48 and 72 h post-implant, and following a challenge dose of morphine (10 mg/kg). Withdrawal signs were determined after naloxone (1 mg/kg) administration. Morphine increased nociceptive threshold which declined over time. At 72 h, acute morphine elicited tolerance to the analgesic effect in the hot plate test in vehicle or tamoxifen administered animals. In the tail immersion test, however, tolerance to morphine analgesia was observed in tamoxifen, but not vehicle, co-administration. Tamoxifen did not reduce withdrawal signs. In contrast to previous reports, glutamate and glutamine levels in the hippocampus and frontal cortex did not change in the morphine-vehicle group. Confirming previous findings, tamoxifen (2 mg/kg) decreased glutamate and glutamine concentrations in the hippocampus in animals with placebo pellets. Both doses of tamoxifen significantly changed glutamate and/or glutamine concentrations in both regions in morphine pellet implanted animals. These results suggest that tamoxifen has no effect on dependence but may facilitate tolerance development to the antinociception, possibly mediated at the spinal level, in chronic morphine administration.

Outcome of Low Dose of Tamoxifen for Ocular Manifestations in Breast Cancer Patients

Background: Tamoxifen, a non-steroidal triphenylethylene estrogen antagonist, serves as a crucial therapy, both alone and in conjunction with other treatments, for disseminated breast carcinomas due to its proven efficacy and minimal adverse effects in oncology. Despite its extensive use, ocular toxicity reports linked to tamoxifen remain relatively scarce in available literature. Given the limited studies in the Bangladeshi context, this investigation aims to explore ocular manifestations in breast cancer patients undergoing prolonged low-dose tamoxifen therapy for over two years. Methods: This longitudinal study was conducted at Dhaka Medical College Hospital between October 2019 and July 2020, involving 45 patients undergoing low-dose tamoxifen treatment for more than two years post-surgical intervention for breast carcinoma. Detailed patient histories were obtained, and thorough ophthalmic examinations were performed for each participant. Data were meticulously recorded in separate case files and analyzed using SPSS 22 to ensure accuracy and reliability. Observations and Results: The average age of the patients was 51.16 (±8.82) years, and 11.10% of the respondents exhibited ocular manifestations. These manifestations primarily comprised cataracts (6.70%), retinitis (2.20%), and optic neuritis (2.20%). Regarding eye-related conditions, cataracts are evident in patients 01, 02, and 03, while retinitis is observed in patients 04 and 05. Optic neuritis is specifically noted in patient 05. The data highlights occurrences of these conditions in relation to the duration of Tamoxifen treatment and the patients' ages, potentially suggesting associations worthy of further exploration regarding the impact of Tamoxifen on eye health in this demographic. Conclusion: This study revealed that approximately one-tenth of the patient cohort undergoing tamoxifen therapy for over two years experienced ocular manifestations. However, further in-depth investigations are strongly ...

The interplay between tamoxifen and endoxifen plasma concentrations and coagulation parameters in patients with primary breast cancer

BackgroundTamoxifen is an effective treatment for primary breast cancer but increases the risk for venous thromboembolism. Tamoxifen decreases anticoagulant proteins, including antithrombin (AT), protein C (PC) and tissue factor (TF) pathway inhibitor, and enhances thrombin generation (TG). However, the relation between plasma concentrations of both tamoxifen and its active metabolite endoxifen and coagulation remains unknown. MethodsTamoxifen and endoxifen were measured in 141 patients from the prospective open-label intervention TOTAM-study after 3 months (m) and 6 m of tamoxifen treatment. Levels of AT and PC, the procoagulant TF, and TG parameters were determined at both timepoints if samples were available (n = 53–135 per analysis). Levels of coagulation proteins and TG parameters were correlated and compared between: 1) quartiles of tamoxifen and endoxifen levels, and 2) 3 m and 6 m of treatment. ResultsAt 3 m, levels of AT, PC, TF and TG parameters were not associated with tamoxifen nor endoxifen levels. At 6 m, median TF levels were lower in patients in the 3rd (56.6 [33] pg/mL), and 4th (50.1 [19] pg/mL) endoxifen quartiles compared to the 1st (lowest) quartile (76 [69] pg/mL) (P=0.027 and P=0.018, respectively), but no differences in anticoagulant proteins or TG parameters were observed. An increase in circulating TF levels (3 m: 46.0 [15] versus 6 m: 54.4 [39] pg/mL, P < 0.001) and TG parameters was observed at the 6 m treatment timepoint, while AT and PC levels remained stable. ConclusionsOur results indicate that higher tamoxifen and endoxifen levels are not correlated with an increased procoagulant state, suggesting tamoxifen dose escalation does not further promote hypercoagulability.

Caspase 8 Deletion Causes Infection/Inflammation-Induced MDS-like Bone Marrow Failure in Mice

Myelodysplastic syndromes (MDS) are a heterogeneous group of pre-leukemic hematopoietic disorders characterized by persistent cytopenia in peripheral blood (PB) and normo- or hypercellular and morphologic dysplasia in bone marrow (BM) due to ineffective hematopoiesis, as well as resulting in an elevated risk for leukemic transformation. Bacterial or viral infections increase the severity of MDS patients' symptoms. An inflammatory BM micro-environment and programmed cell death of hematopoietic stem/progenitor cells (HSPCs) have been thought to be the major causes leading to ineffective hematopoiesis. Three types of programed cell death, apoptosis, necroptosis and pyroptosis, were observed in BM tissues of MDS patients, suggesting PANoptosis might play a critical role in the pathogenesis of MDS. Caspase 8 (Casp8) is a master regulator of PANoptosis. Casp8 is downregulated in HSPCs from patients with MDS, and is associated with increased Ripk1 protein, which is another master regulator of PANoptosis. To study the role of PANoptosis in normal hematopoiesis and the pathogenesis of MDS, we generated Mx1-Cre and Rosa-ERT 2Cre-mediated inducible C asp8 knockout mice ( Casp8 -/-). Mx1-CreCasp8 -/- mice died of BM failure within 10 days of three polyI:C injections (administered every other day) due to the massive depletion of HSPCs. This could be completely rescued by Ripk3 deletion, suggesting that HSPCs were eliminated by necroptosis. Rosa-ERT 2Cre- Casp8 -/- mice are completely normal without any significant changes in BM hematopoiesis after induction by five doses of tamoxifen (TAM) when maintained in specific pathogen-free facilities. However, such mice developed a spontaneous BM failure phenotype when maintained in quarantine facilities. This BM failure can be attenuated by antibiotic treatment, suggesting that the phenotype is infection-induced. In addition, low dose polyI:C injections or treatment with LPS also induces BM failure in Rosa-ERT 2Cre - Casp8 -/- mice living in germ-free conditions. Detailed analysis suggested that Casp8 -/- HSPCs are hypersensitive to polyI:C, LPS, TNFα and IFNα/γ-induced cell death. Most importantly, all these phenotypic and functional abnormalities observed in Rosa-ERT 2Cre- Casp8 -/- mice can be completely prevented by Ripk3 deletion. In addition, serial transplantationstudy demonstrated that Casp8 -/- HSCs have impaired self-renewal capacity. Interestingly, the self-renewal of Casp8 -/-Ripk3 -/- HSCs is significantly enhanced compared to Wild-type HSCs. Our study suggests an essential role for a balance in Casp8 and Ripk3 activities in the regulation of normal hematopoiesis and the self-renewal of HSCs, the disruption of which might induce inflammation and BM failure, resulting in MDS-like disease.

In-vivo anticancer activity of biosynthetic silver nanoparticles of Cassia marginata Roxb against NMU-Induced mammary carcinoma

The use of silver nanoparticles in the diagnosis and treatment of cancer is on the rise, and they are becoming more commonly recognized as effective therapeutic agents. Silver nanoparticles of Cassia marginata Roxb were prepared to investigate its anticancer potential in female Sprague-Dawley rats against N-nitroso N-methyl urea-induced mammary carcinoma. In this study, thirty animals were divided into five groups of six each: normal, disease control, Cassia marginata silver nanoparticles at 200 mg/kg, 400 mg/kg, and tamoxifen 10 mg/kg. N-nitroso N-methyl urea (50 mg/kg, i.p) was given twice at 52 days of age and four weeks after the prior treatment in 0.9 % NaCl. A total of two oral doses of Cassia marginata silver nanoparticles were administered, and the results were compared to the results of a single dose of tamoxifen (10 mg/kg, p.o). The tumor incidence rate, average tumor burden, and the total number of tumors were reduced in the treatment groups when compared with the disease control and the silver nanoparticles of Cassia marginata may prevent mammary carcinoma in Sprague-Dawley rats when exposed to N-nitroso N-methyl urea.

Fate mapping reveals compartment-specific clonal expansion of mononuclear phagocytes during kidney disease

Fate mapping reveals compartment-specific clonal expansion of mononuclear phagocytes during kidney disease