Nuclear Fraction Research Articles

Abstract PO3-25-05: Eribulin Induces Chromosomal Instability and Enhances cGAS Expression in the Nucleus of Triple-Negative Breast Cancer

Abstract Background: Eribuliln (ERI), a microtubule polymelization, is approved for locally advanced or metastatic breast cancer. However, its effects on drug-naive cancers are not well understood. In EMBRACE trial, ERI improves overall survival (OS) of the patients with metastatic breast cancer. This result might suggest that ERI could be involved in the immune system. In particular, there are a few reports on the effects of ERI on the innate immune system. This study aimed to investigate how ERI influences the innate immune system, focusing on the cyclic-GMP-AMP synthase (cGAS), a DNA sensor that triggers the production of type-I interferons. Methods: Clinical samples from the JONIE-3 trial were analyzed using immunohistochemistry (IHC). 121 patients were assigned to 2 different neoadjuvant chemotherapy (NAC) groups receive ERI (Group E) or paclitaxel (Group P) followed by FEC. The patients of both groups were performed biopsy before and after chemotherapy. We performed IHC on 56 samples and examined for association with pathological complete response (pCR), which was defined as no invasive redidual tumor tissue in the breast. Additionally, 5 different cell lines were established to evaluate the acute and chronic effects of ERI treatment. The cell lines were as follows: no treatment (control), PTX for short time (PTX short), PTX for long time (PTX long), ERI for short time (ERI short) and ERI for long time (ERI long). We evaluated the acute effects of short-term dosing, while the chronic effects of long-term dosing, which mimic resistance to treatment. Protein expression of the cGAS-STING pathway was examined, along with cGAS and IFNβ expression levels and their impact on cell division in the above cell lines. Then at the cellular level, each cell lines were evaluated for differences in cGAS and IFNβ expression and their effects on cell division. The differences in cGAS expression between cytoplasmic and nuclear fractions were verified by the cell fractuation assay. In addition, mitotic abnormalities and cell proliferation were also assessed. Results: In the clinical trial, ERI did not significantly differ from paclitaxel in terms of pathological complete response (pCR). However, high cGAS expression in Group E (ERI) correlated with increased pCR rates, while no such correlation was observed in Group P (PTX) (Figure). Additionally, High IFNβ expression in Group E also correlated with increased pCR rates, differed from Group P. In vitro, ERI upregulated cGAS, STING, pIRF3, and IFNβ protein expression compared to PTX. Notably, ERI induced elevated cGAS expression in the nucleus, as confirmed by immunofluorescence and cell fracturation assays. Additionally, PTX and ERI differed in their ability to cause mitotic abnormalities. PTX induced more micronuclei cells than ERI, on the other hand ERI induced more micronuclei cells and mitotic slippage. These results were also verified by live cell imaging. Finally, the knockdown of cGAS resulted in accelerated cell proliferation. Conclusion: ERI promoted chromosomal instability, leading to increased cGAS expression, particularly in the nucleus. These findings contribute to our understanding of ERI's effects on the innate immune response in triple-negative breast cancer, potentially paving the way for improved therapeutic strategies. The differences in intensity scores between GroupP and GroupE in the immunostaining of cGAS High cGAS expression in Group E correlated with increased pCR rates (p=0.0375), while no such correlation was observed in Group P (p=0.2983). Citation Format: Hideyuki Yamada, Mamoru Takada, Aussie Suzuki, Yu Muhan, Takeshi Nagashima, Hiroshi Fujimoto, Junta Sakakibara, Masaharu Kasuya, Takahiko Kawate, Daishu Miura, Masato Suzuki, Masaru Miyashita, Kazutaka Narui, Yoshie Hasegawa, Takashi Ishikawa, Masayuki Otsuka. Eribulin Induces Chromosomal Instability and Enhances cGAS Expression in the Nucleus of Triple-Negative Breast Cancer [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 PO3-25-05.

Abstract PS17-09: An FGFR1/2 degrader overcomes antiestrogen resistance in ER+/FGFR1-amplified breast cancer

Abstract We previously reported that nuclear FGFR1 promotes antiestrogen resistance in ER+/FGFR1-amplified breast cancer. Nuclear FGFR1 activity was not affected by FGFR tyrosine kinase inhibitors (TKIs). Furthermore, pan-FGFR TKIs are not well tolerated. Therefore, new therapeutic strategies that inhibit nuclear FGFR1 while sparing FGFR3 and FGFR4 would be required to overcome antiestrogen resistance and limit toxicity. For this study, we used the proteolysis-targeting chimera (PROTAC) DGY-09-192, consisting of the FGFR TKI BCJ398 linked with a VHL recruiting ligand, to degrade FGFR1 and FGFR2. We aimed to determine whether selective degradation of FGFR1/2 overcomes endocrine resistance. Treatment with 50-100 nM DGY-09-192 strongly induced FGFR1 degradation and suppressed phosphorylation of FGFR1 and its downstream targets FRS2, AKT, and ERK1/2 in ER+/FGFR1-amplified CAMA1 and MDA-MB-134 breast cancer cells. FGFR1 degradation was evident within 4 h and lasted 48-96 h after drug washout. The proteasome inhibitor MG132 (10 µM) rescued both FGFR degradation and phosphorylation of downstream signaling molecules induced by DGY-09-192, confirming that FGFR1 degradation is dependent on ubiquitination and proteasomal degradation. At equivalent concentrations, DGY-09-192 suppressed phosphorylation of FGFR1 and its downstream targets more potently than BGJ398. Subcellular fractionation showed treatment with DGY-09-192 (100 nM) degraded FGFR1 in membrane, nuclear, and chromatin-bound fractions in both CAMA1 and MDA-MB-134 cells. Treatment of >CAMA1 cells with DGY-09-192 (>100 nM) downregulated nuclear FGFR1 target genes and canonical ERα target genes, such as CCND1, VEGFA, and CDK12 as measured by qRT-PCR whereas treatment with BGJ398 (100 nM) did not. Treatment with DGY-09-192 (500 nM) reversed resistance to the ER degrader fulvestrant in CAMA1 cells as measured by colony formation assays and using the Incucyte Live-Cell Analysis System. Each drug alone showed a modest effect on cell proliferation whereas the combination completed blocked cell growth (p < 0.0001). Finally, treatment of NOD scid gamma (NSG) mice with established ER+/FGFR1-amplified HCI-011 patient-derived xenografts with DGY-09-192 (40 mg/kg daily x2-6) induced FGFR1 degradation and blocked phosphorylation of downstream targets in the tumors. Studies using the combination of DGY-09-192 and fulvestrant in mice bearing established HCI-011 xenografts are in progress. We next investigated the effect of DGY-09-192 on cancer cells harboring FGFR1 and FGFR2 activating mutations. DGY-09-192 treatment induced FGFR2 degradation and blocked downstream signaling in MFE296 endometrial cancer and EFM-19 breast cancer cells that harbor the FGFR2N549K and FGFR2K659E hotspot mutations, respectively. In addition, DGY-09-192 strongly suppressed MFE296 cell proliferation. We are currently investigating whether DGY-09-192 blocks signaling and cell proliferation induced by the N546K and K656E hotspot FGFR1 mutations in ER+ breast cancer cells. Notably, a recent clinical study showed that tumors harboring these FGFR1 activating mutations are refractory to the pan-FGFR TKI pemigatinib. Conclusions: The FGFR1/2 PROTAC DGY-09-192 induced degradation of nuclear and membrane-bound FGFR1 and blocked FGFR1-induced signaling and nuclear activity in ER+/FGFR1-amplified breast cancer cells. The combination of DGY-09-192 and fulvestrant synergistically suppressed proliferation of these cells. Therefore, FGFR1 degradation represents a promising therapeutic strategy to block FGFR1 activity more completely and selectively in ER+ breast cancers harboring activating FGFR1 alterations. Citation Format: Yasuaki Uemoto, Chang-Ching Lin, Alberto Servetto, Bingnan Wang, Dan Ye, Fabiana Napolitano, Hima Milan Patel, Luigi Formisano, M Rosario Chica-Parrado, Emmanuel Bikorimana, Saurabh Mendiratta, Chuo Chen, Ariella Hanker, Carlos Arteaga. An FGFR1/2 degrader overcomes antiestrogen resistance in ER+/FGFR1-amplified breast cancer [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 PS17-09.

Yes-associated Protein Mediates Acute Lung Injury in Adult but not Juvenile Mice

Objective: Adults with The Acute Respiratory Distress Syndrome (ARDS) have worse outcomes than children with Pediatric ARDS. This finding can be reproduced in animal models, suggesting a difference in Acute Lung Injury (ALI) mechanisms. Understanding these mechanistic differences could inform age-specific treatment. Hypothesis: Since Yes-associated protein (YAP) is important for lung development and reactive to mechanical stretch, we hypothesized that YAP is important for ALI mechanisms. Methods: To induce ALI, we intranasally instilled mice with Pseudomonas aeruginosa strain K (2.5 x 105 colony forming units (c.f.u.)) in juvenile (3-week-old) and adult (10-week-old) C57BL/6J mice. 24 h later, we collected bronchoalveolar lavage (BAL) fluid and measured protein, cell count, and c.f.u. To knockdown YAP expression, we injected siRNA 24 h before P. aeruginosa instillation. We removed the lungs and enriched for CD45+ and CD41+ fraction, and CD31+ fraction using Dynabeads sheep anti-rat IgG (Invitrogen). In separate experiments, lungs were separated into nuclear and cytosolic fractions for immunoblot analysis. For immunoprecipitation, the cytosolic fraction was added to beads coated with anti-YAP antibody (rabbit monoclonal). We washed the beads and eluted bound proteins, which were identified by label-free mass spectrometry. Data and results: While both juvenile and adult mice had significantly increased BAL cell counts and protein 24 h after P. aeruginosa instillation, adult mice had significantly greater cell counts and protein than juveniles. BAL c.f.u. were similar in both groups, suggesting equal instillation of P. aeruginosa. P. aeruginosa instillation increased whole lung YAP expression in both cytosolic and nuclear fractions in adult mice by >3-fold, but YAP expression was not increased in P. aeruginosa-treated juvenile mice. YAP protein increases occurred in CD31+ fraction (endothelial cells), but no YAP was quantified in CD45+/CD41+ fraction (leukocytes and platelets). Vascular knockdown of YAP expression by ~75% in adult mice blocked P. aeruginosa-induced BAL cell count increases. Proteomics analysis revealed 62 proteins that had significantly altered YAP binding upon P. aeruginosa treatment (47 with increased YAP binding). The complement factors H and I had a log2-fold-change for YAP binding of 4.56 and 2.26, respectively, upon P. aeruginosa treatment. Conclusions: Adult mice exhibited YAP-dependent Acute Lung Injury; juveniles did not. YAP-dependent mechanisms of injury may be secondary to YAP binding to the complement inhibitory proteins H and I. More work is needed to establish the cell-specificity of YAP-complement factor binding and to determine the location of complement signaling. HL148403, Parker B Francis, and Columbia University Department of Pediatrics Children’s Health Innovation Nucleation Fund to RFH; Ernest E Just Summer Scholarship to AMD. 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.

Biochemical Separation of Cytoplasmic and Nuclear Fraction for Downstream Molecular Analysis.

Biochemical fractionation is a technique used to isolate and separate distinct cellular compartments, critical for dissecting cellular mechanisms and molecular pathways. Herein we outline a biochemical fraction methodology for isolation of ultra-pure nuclei and cytoplasm. This protocol utilizes hypotonic lysis buffer to suspend cells, coupled with a calibrated centrifugation strategy, for enhanced separation of cytoplasm from the nuclear fraction. Subsequent purification steps ensure the integrity of the isolated nuclear fraction. Overall, this method facilitates accurate protein localization, essential for functional studies, demonstrating its efficacy in separating cellular compartments. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Biochemical fractionation Support Protocol 1: Protein quantification using Bradford assay Support Protocol 2: SDS/PAGE and Western blotting.

A Novel Mechanism Underlying Apoptosis Resistance in Pulmonary Arterial Smooth Cuscle Cells (PASMCs)

RATIONALE: Pulmonary hypertension (PH) is characterized by pulmonary vascular remodeling, with PASMC hyperplasia and formation of vaso-occlusive lesions. New data show PASMCs isolated from robust animal models of PH are resistant to apoptosis, a feature which may propagate disease as abnormal PASMCs evade death. Apoptosis is a highly regulated pathway resulting in caspase-3 (casp3) activation and translocation to the nucleus, where cleavage of proteins results in cell death. In several cancers the membrane protein aquaporin 1 (AQP1) plays a role in apoptosis resistance, although the mechanism remains unknown. We showed AQP1 is expressed in PASMCs and increased in rat models of PH. Therefore, we hypothesized increased AQP1 contributes to apoptosis resistance in PASMCs. METHODS: The Sugen-hypoxia (SuHx) rat model of PH was used. Rats were injected with vascular endothelial growth factor receptor type 2 inhibitor Sugen-5416 and placed in 10% O2 for 3 wk, then returned to 21% O2 for 2 wk. Control animals received vehicle injection and were kept in 21% O2. Distal PASMCs were isolated via enzymatic digestion. AQP1 was depleted in SuHx PASMCs with small interfering RNA (siAQP1), with non-targeting siRNA as control. AQP1 was overexpressed in control PASMCs with adenoviral constructs containing wild type AQP1 (AdAQP1) or green fluorescent protein (control). Cells were treated with PBS or pro-apoptotic hydrogen peroxide (500 μM; 24 h). Apoptosis was measured by Hoechst staining. Caspase activity was measured via luminescent caspase-3/7 activity assay (Caspase-Glo® 3/7) in whole cell lysates and nuclear fractions. RESULTS: Depleting AQP1 via siAQP1 restored apoptosis susceptibility in SuHx PASMCs, and overexpressing AQP1 via AdAQP1 reduced susceptibility to apoptosis in control PASMCs. At baseline, there was no difference in casp3 activity between SuHx and control total cell lysates. However, casp3 activity was lower in SuHx nuclear fractions. Under stimulated conditions, SuHx PASMCs exhibited significantly less total and nuclear casp3 activity, with nuclear activity similar to levels observed in unstimulated controls. To explore an underlying mechanism for these findings, in silico analysis of AQP1 was performed revealing 3 potential casp3 cleavage sites, suggesting the possibility these proteins could interact. To investigate a potential protein-protein interaction, proximity-based biotinylation assays were performed in PASMCs using AdAQP1 (control) or AQP1 fused to biotin ligase. Cells were incubated with cell-permeable biotin (50 μM), lysed, and biotinylated proteins precipitated and immunoblotted for casp3 and other cytosolic proteins not expected to interact with AQP1. To confirm bidirectionality, similar biotinylation assays were performed using adenoviral constructs with wild-type (control) or biotin ligase-fused casp3 and immunoblotting for AQP1. Results showed a specific AQP1/casp3 interaction in PASMCs. Furthermore, the predominant form of casp3 interacting with AQP1 appears to be inactive (37kD). CONCLUSION: We speculate that increased AQP1 in SuHx PASMCs interacts with casp3 preventing its activation and/or nuclear translocation, conferring apoptosis resistance. Future studies further characterizing the interaction between AQP1 and casp3 could provide the basis for novel therapeutic targets focused on restoring PASMC apoptosis susceptibility. F32 HL165766-01, T32 HL007534, Bauernschmidt Fellowship. 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.

Artificial Extracellular Vesicles Generated from T Cells Using Different Induction Techniques.

Cell therapy is at the forefront of biomedicine in oncology and regenerative medicine. However, there are still significant challenges to their wider clinical application such as limited efficacy, side effects, and logistical difficulties. One of the potential approaches that could overcome these problems is based on extracellular vesicles (EVs) as a cell-free therapy modality. One of the major obstacles in the translation of EVs into practice is their low yield of production, which is insufficient to achieve therapeutic amounts. Here, we evaluated two primary approaches of artificial vesicle induction in primary T cells and the SupT1 cell line-cytochalasin B as a chemical inducer and ultrasonication as a physical inducer. We found that both methods are capable of producing artificial vesicles, but cytochalasin B induction leads to vesicle yield compared to natural secretion, while ultrasonication leads to a three-fold increase in particle yield. Cytochalasin B induces the formation of vesicles full of cytoplasmic compartments without nuclear fraction, while ultrasonication induces the formation of particles rich in membranes and membrane-related components such as CD3 or HLAII proteins. The most effective approach for T-cell induction in terms of the number of vesicles seems to be the combination of anti-CD3/CD28 antibody activation with ultrasonication, which leads to a seven-fold yield increase in particles with a high content of functionally important proteins (CD3, granzyme B, and HLA II).

Customizable Porphyrin Platform Enables Folate Receptor PET Imaging Using Copper-64.

Folate receptors including folate receptor α (FRα) are overexpressed in up to 90% of ovarian cancers. Ovarian cancers overexpressing FRα often exhibit high degrees of drug resistance and poor outcomes. A porphyrin chassis has been developed that is readily customizable according to the desired targeting properties. Thus, compound O5 includes a free base porphyrin, two water-solubilizing groups that project above and below the macrocycle plane, and a folate targeting moiety. Compound O5 was synthesized (>95% purity) and exhibited aqueous solubility of at least 0.48 mM (1 mg/mL). Radiolabeling of O5 with 64Cu in HEPES buffer at 37 °C gave a molar activity of 1000 μCi/μg (88 MBq/nmol). [64Cu]Cu-O5 was stable in human serum for 24 h. Cell uptake studies showed 535 ± 12% bound/mg [64Cu]Cu-O5 in FRα-positive IGROV1 cells when incubated at 0.04 nM. Subcellular fractionation showed that most radioactivity was associated with the cytoplasmic (39.4 ± 2.7%) and chromatin-bound nuclear (53.0 ± 4.2%) fractions. In mice bearing IGROV1 xenografts, PET imaging studies showed clear tumor uptake of [64Cu]Cu-O5 from 1 to 24 h post injection with a low degree of liver uptake. The tumor standardized uptake value at 24 h post injection was 0.34 ± 0.16 versus 0.06 ± 0.07 in the blocking group. In summary, [64Cu]Cu-O5 was synthesized at high molar activity, was stable in serum, exhibited high binding to FRα-overexpressing cells with high nuclear translocation, and gave uptake that was clearly visible in mouse tumor xenografts.

Diagnostic Utility of Cytomorphometric Evaluation of Exfoliated Oral Mucosal Cells in Type II Diabetes Mellitus: A Systematic Review and Meta-analysis.

Diabetes Mellitus (DM) is the sixth leading cause of mortality and morbidity in the world. Early diagnosis and periodic monitoring are mandatory to prevent complications. The custom of noninvasive exfoliative cytology diagnostic technique is the need of the hour in diabetes, where the invasive methods lose viability. The purpose of this meta-analysis is to analyze the cytomorphometric changes in the exfoliated cells of the oral mucosa, as an adjunct to the diagnosis of type II diabetes. A thorough search was made by using PubMed, Google Scholar, and Cochrane Library databases. Original research articles, that evaluated cytomorphometric parameters (nuclear area, cytoplasmic area, cytoplasmic nuclear ratio) in type II diabetes patients were included in this review. Risk of bias was analysed for each study using Joanna Briggs Institute and Review Manager was used for meta-analysis. All nine subgroups included for qualitative and quantitative data synthesis revealed that there was a significant increase in nuclear area and a decrease in cytoplasmic nuclear ratio in diabetic patients as compared to non-diabetics. Random-effects model also confirmed cytologically altered (nuclear area and cytoplasmic nuclear ratio) parameters to have a significantly increased risk of association with diabetes. Furthermore, these morphometry parameters were also associated with glycemic control and there was no gender disparity among them. Mounting evidence authenticate that cytomorphometric analysis of oral mucosal cells using exfoliative cytology might be aid as an adjunct non-invasive diagnostic tool for type II diabetes.

Atypical meningiomas compared to other WHO Grade 2 meningiomas: Histological features and prognosis.

To study each atypical feature in atypical meningioma versus other grade 2 meningiomas and its possible relation to recurrence. This is a retrospective study of patients with WHO grade 2 meningioma operated in our institution between 01/2008 and 12/2020. The rate of recurrence, reoperation and readmission were recorded during the follow-up period. A statistical analysis was done to determine the significance of each pathological feature in regard to recurrence. A total of 74 patients were included as WHO grade 2 meningioma with 60 (81%) patients having an AM and 14 (19%) patients with chordoid or clear cell meningioma. The mean age was 51 years±14. The most common location was meningioma abutting the frontal lobe (convexity). Major atypical features were more noted in the AM, however, there was no significant difference between AM and other types of meningioma. Increased Nuclear cytoplasmic ratio and cellularity were found significantly more in AM. The recurrence rate was 16.2%. No specific pathology feature (major or minor) nor the type of Grade 2 meningioma was significantly related to recurrence. The types of WHO grade 2 meningiomas have similar prognosis and recurrence rates. There is no significant difference between the atypical features in indicating a more aggressive nature or risk of recurrence in grade 2 meningiomas.

Nuclear KRT19 is a transcriptional corepressor promoting histone deacetylation and liver tumorigenesis.

Epigenetic reprogramming and escape from terminal differentiation are poorly understood enabling characteristics of liver cancer. Keratin 19 (KRT19), classically known to form the intermediate filament cytoskeleton, is a marker of stemness and worse prognosis in liver cancer. This study aimed to address the functional roles of KRT19 in liver tumorigenesis and to elucidate the underlying mechanisms. Using multiplexed genome editing of hepatocytes in vivo, we demonstrated that KRT19 promoted liver tumorigenesis in mice. Cell fractionation revealed a previously unrecognized nuclear fraction of KRT19. Tandem affinity purification identified histone deacetylase 1 and REST corepressor 1, components of the corepressor of RE-1 silencing transcription factor (CoREST) complex as KRT19-interacting proteins. KRT19 knockout markedly enhanced histone acetylation levels. Mechanistically, KRT19 promotes CoREST complex formation by enhancing histone deacetylase 1 and REST corepressor 1 interaction, thus increasing the deacetylase activity. ChIP-seq revealed hepatocyte-specific genes, such as hepatocyte nuclear factor 4 alpha ( HNF4A ), as direct targets of KRT19-CoREST. In addition, we identified forkhead box P4 as a direct activator of aberrant KRT19 expression in liver cancer. Furthermore, treatment of primary liver tumors and patient-derived xenografts in mice suggest that KRT19 expression has the potential to predict response to histone deacetylase 1 inhibitors especially in combination with lenvatinib. Our data show that nuclear KRT19 acts as a transcriptional corepressor through promoting the deacetylase activity of the CoREST complex, resulting in dedifferentiation of liver cancer. These findings reveal a previously unrecognized function of KRT19 in directly shaping the epigenetic landscape in cancer.

ГЕПАТОПРОТЕКТОРНАЯ АКТИВНОСТЬ ПРОИЗВОДНОГО 2-АМИНОЭТАНСУЛЬФОНОВОЙ КИСЛОТЫ ПРИ ЛЕКАРСТВЕННОМ ПОРАЖЕНИИ ПЕЧЕНИ В ЭКСПЕРИМЕНТЕ

We studied the hepatoprotective activity of 2-aminoethanesulfonic acid derivative (laboratory code LBK-527) in antibiotic-associated liver injury. The studies were performed on 18 laboratory rats (Wistar line), divided into four groups: 1st - intact animals, 2nd - control group with tetracycline drug-induced liver injury (TDLI), 2nd group - experimental with DILI and injected LBK- 527 (28 mg/kg), group 3 – experimental with DILI, injected N-adenosyl-S-methionine for 14 days. DILI was induced by intragastric administration of tetracycline at a dose of 500 mg/kg for 5 days. Animals were removed from the experiment on 7 and 14 days and studied activity of aspartic (AST) and alanine (ALT) aminotransferases, total protein (TP), total bilirubin (TB), alkaline phosphatase (ALP), and creatinine (C). The liver was taken from all animals, weighed, and the macro- and microstructure was assessed, stained with hemotoxylin and eosin according to the standard method using a Nikon Eclipes Ni light microscope (Japan). Antibiotic-associated liver injury occurs of the cholestatic type and is characterized by an increase in ALP, TB and the ALT/ALP ratio by two times, decomposition of the hepatic beams, moderate necrosis, fatty degeneration of hepatocytes by 7 days. The administration of LBK-527 and N-adenosyl-S-methionine reduced the toxic effect of tetracycline on the liver, which was manifested in a decrease in the activity of cytolytic icholestatic syndromes, preservation of the beam structure of the liver, degeneration and congestion in the hepatic veins. By day 14, in the control group of animals there was a decrease in the activity of intracellular enzymatic systems of hepatocytes, but complete restoration of the liver structure did not occur in comparison with the intact group. Compound LBK-527 by day 14 The area of the cytoplasm, nucleus and nuclear-cytoplasmic ratio approached the values of the intact group. The appearance of multinucleated hepatocytes indicated the activation of the synthetic activity of the liver and the launch of regeneration mechanisms. Thus, we can conclude that the pharmaceutical composition under study has a hepatoprotective effect.

The ADAM17 inhibitor ZLDI-8 sensitized hepatocellular carcinoma cells to sorafenib through Notch1-integrin β-talk

ZLDI-8 is an A disintegrin and metalloproteinase domain 17 (ADAM17) inhibitor that suppresses the shedding of Notch1 to the Notch1 intracellular domain (NICD). In previous studies, we found that ZLDI-8 was able to sensitize HCC to sorafenib, but the mechanism of action remains unclear. The sensitizing effects of ZLDI-8 were tested both in vitro and in vivo. EMT-related factors, sorafenib sensitivity-related proteins and ECM-related gene expression were assessed using immunohistochemistry, RTPCR and Western blotting. Knockdown assays were conducted to determine the relationship between the Notch and Integrin pathways. CoIP assays, nuclear and cytoplasmic fractionation and immunofluorescence colocalization were applied to explore the interaction between the Notch and Integrin pathways. Appropriate statistical analysis methods were used to assess the significance of the experimental results and to ensure the scientific validity and reliability of the experimental design. We found that ECM- and EMT-related proteins were downregulated after ZLDI-8 treatment (P<0.05). ZLDI-8 significantly downregulated Integrinβ1 and Integrinβ3 in HCC in vitro and in vivo (P<0.05), possibly through Foxc2-dependent regulation. Mechanistically, interfering with the expression of both Integrin-linked kinase (ILK) and the NICD may downregulate the expression of proteins targeted by sorafenib, thereby sensitizing cells to sorafenib. The retroregulation of Integrinβ by ILK may occur through the interaction between the NICD and ILK and may be the result of the translocation of the complexus. Our study indicates that blocking the Notch pathway may affect Integrinβ through crosstalk between the Notch1 and Integrinβ/ILK signaling pathways, thus providing a potential therapeutic strategy for HCC.

Abstract 3079: AMPK-HIF-1α signaling enhances glucose-derived de novoserine biosynthesis to promote glioblastoma growth

Abstract Cancer cells undergo cellular adaptation through metabolic reprogrammin to sustain survival and rapid growth under various stress conditions. However, it remains unknown how brain tumors modulate their metabolic flexibility in the naturally serine/glycine (S/G)-deficient brain microenvironment. We used a range of primary/stem-like and established glioblastoma (GBM) cell models in vitro and in vivo. To identify regulatory mechanisms of S/G deprivation induced metabolic flexibility, we employed high throughput RNA-sequencing, transcriptomic analysis, metabolic flux analysis, metabolites analysis, chromatin immunoprecipitation (ChIP), luciferase reporter, nuclear fractionation, cycloheximide-chase, and glucose consumption. The clinical significances were analyzed in the genomic database (GSE4290) and in human GBM specimens. The high throughput RNA-sequencing and transcriptomic analysis demonstrate that the de novo serine synthesis pathway (SSP) and glycolysis are highly activated in GBM cells under S/G deprivation conditions. Mechanistically, S/G deprivation rapidly induces reactive oxygen species (ROS)-mediated AMP-activated protein kinase (AMPK) activation and AMPK dependent hypoxia-inducible factor (HIF)-1α stabilization and transactivation. Activated HIF-1α in turn promotes expression of SSP enzymes phosphoglycerate dehydrogenase (PHGDH), phosphoserine aminotransferase 1 (PSAT1), and phosphoserine phosphatase (PSPH). In addition, HIF-1α-induced expression of glycolytic genes (GLUT1, GLUT3, HK2, and PFKFB2) promotes glucose uptake, glycolysis, and glycolytic flux to fuel SSP, leading to elevated de novo serine and glycine biosynthesis, NADPH/NADP+ ratio, and proliferation and survival of GBM cells. Analyses of human GBM specimens reveal that levels of overexpressed PHGDH, PSAT1, and PSPH are positively correlated with levels of AMPK T172 phosphorylation and HIF-1α expression and poor prognosis of GBM patients. Our findings reveal that metabolic stress-enhanced glucose-derived de novo serine biosynthesis is a critical metabolic feature of GBM cells and highlight the potential to target SSP for treating human GBM. Citation Format: Hye Jin Yun, Jong-Ho Lee. AMPK-HIF-1α signaling enhances glucose-derived de novoserine biosynthesis to promote glioblastoma growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3079.

Abstract 689: BUB1 interferes with the repair of radiation-induced DNA damage to radiosensitize triple-negative breast cancer

Abstract Triple-negative breast cancer (TNBC) is associated with locoregional recurrence and low survival rates. Novel molecular targets are expected to improve the efficacy of radiation therapy (RT) in TNBC. BUB1, a mitotic checkpoint Serine/Threonine-protein kinase is known to impact chromosomal segregation during mitosis. However, its precise role in DNA damage repair in response to RT remains largely unknown. We demonstrated that BUB1 is overexpressed in BC (vs. normal breast) and considerably raised in TNBC with poor survival outcomes using differential gene expression analysis. In multiple TNBC cell lines, cell proliferation assays revealed that pharmacological (BAY1816032) or genomic (CRISPR) ablation of BUB1 was cytotoxic. Using clonogenic survival assays, we observed that BUB1 ablation radiosensitized TNBC cell lines (SUM159, MDA-MB-231, MDA-MB-468, BT-549) while its ablation did not radiosensitized breast epithelial cells (MCF10A). Furthermore, by depleting endogenous BUB1 (siRNAs and CRISPR) and reintroducing wild-type (WT) or kinase-dead (KD) BUB1, we demonstrated that inhibition of BUB1 kinase function is responsible for the radiosensitization phenotype. BUB1 ablation increased tumor doubling time in SUM159 xenografts when combined with radiation. Ki67 levels were also reduced in these tumors, confirming the efficacy of the combined treatment. BUB1 ablation led to persistent radiation-induced DNA DSB (gH2AX foci) indicating decreased DNA-DSB repair. BLRR assays confirmed that BUB1 impacts the non-homologous end joining (NHEJ) pathway. Biochemical analyses showed that BUB1 ablation stabilized total- and phospho- DNAPKcs (S2056) following RT such that half-lives could not be estimated. In contrast, RT alone caused BUB1 stabilization, but pre-treatment with BUB1i and DNAPKi prevented stabilization. To evaluate the recruitment of DDR proteins to the chromatin following RT, soluble nuclear and chromatin-enriched fractionations were performed which illustrated an increase in recruitment of phospho- and total-DNAPK, KAP1, and ATM to chromatin indicating that BUB1 is important in the activation and recruitment of critical NHEJ proteins to DSBs. In addition, BUB1 staining of TNBC TMAs demonstrated significant correlation between BUB1 protein expression with tumor grade and stage in TNBC patients. Our findings demonstrate that ablation of BUB1 sensitizes TNBC cell lines and xenograft to RT and BUB1 mediated radiosensitization may occur through NHEJ. Our results suggest that BUB1 may serve as a novel molecular target for radiosensitization in women with TNBC. Citation Format: Sushmitha Sriramulu, Shivani Thoidingjam, Pin Li, Stephen L. Brown, Farzan Siddiqui, Benjamin Movsas, Michael Green, Corey Speers, Shyam Nyati. BUB1 interferes with the repair of radiation-induced DNA damage to radiosensitize triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 689.

Overexpression of REST Represses the Epithelial-Mesenchymal Transition Process and Decreases the Aggressiveness of Prostate Cancer Cells.

The RE-1 silencing transcription factor (REST) is a repressor factor related to neuroendocrine prostate cancer (PCa) (NEPC), a poor prognostic stage mainly associated with castration-resistant PCa (CRPC). NEPC is associated with cell transdifferentiation and the epithelial-mesenchymal transition (EMT) in cells undergoing androgen deprivation therapy (ADT) and enzalutamide (ENZ). The effect of REST overexpression in the 22rv1 cell line (xenograft-derived prostate cancer) on EMT, migration, invasion, and the viability for ENZ was evaluated. EMT genes, Twist and Zeb1, and the androgen receptor (AR) were evaluated through an RT-qPCR and Western blot in nuclear and cytosolic fractions of REST-overexpressing 22rv1 cells (22rv1-REST). The migratory and invasive capacities of 22rv1-REST cells were evaluated via Transwell® assays with and without Matrigel, respectively, and their viability for enzalutamide via MTT assays. The 22rv1-REST cells showed decreased nuclear levels of Twist, Zeb1, and AR, and a decreased migration and invasion and a lower viability for ENZ compared to the control. Results were expressed as the mean + SD of three independent experiments (Mann-Whitney U test, Kruskal-Wallis, Tukey test). REST behaves like a tumor suppressor, decreasing the aggressiveness of 22rv1 cells, probably through the repression of EMT and the neuroendocrine phenotype. Furthermore, REST could represent a response marker to ENZ in PCa patients.

Assessment of DNA/RNA Deregulation in Cancer Using 99mTc-Labeled Thiopurine.

Background: DNA biomarkers are useful for the assessment of tumor cell proliferation. The authors aimed to synthesize a thiopurine-based ligand for evaluation of nuclear uptake and tumor localization. Materials and Methods: A 2-hydroxypropyl spacer was incorporated between a chelator (cyclam) and thiopurine ligand to produce SC-06-L1. In vitro cellular uptake and the cell/media ratios of [99mTc]Tc-SC-06-L1 were assessed in breast (MCF-7, MDA-MB-231) and ovarian (TOV-112D, OVCAR3) cancer cells. The nuclear and cytosolic uptake ratio of [99mTc]Tc-SC-06-L1 was determined in OVCAR-3 and MCF-7 cells. Cytotoxicity assays and flow cytometric analysis of cell cycle apoptosis were conducted in cancer cells treated with SC-06-L1. Imaging was conducted in tumor-bearing mice; fluorine-18-2'-fluorodeoxyglucose ([18F]FDG) was used as a control. Results: The radiochemical purity of [99mTc]Tc-SC-06-L1 was >95%. [99mTc]Tc-SC-06-L1 exhibited higher cell-to-media ratios than [18F]FDG in cancer cells. [99mTc]Tc-SC-06-L1 had high uptake in the nuclear fractions in OVCAR-3 and MCF-7 cells, with nuclear/cytosolic ratios of 8 and 2, respectively. Cytotoxicity assays showed that SC-06-L1 was non-toxic compared with azathioprine in breast and ovarian cancer cells. Conclusions: [99mTc]Tc-SC-06-L1 was stable and involved in nuclear activities. [99mTc]Tc-SC-06-L1 showed non-toxic to cancer cells and exhibited fast kinetic uptake patterns for tumor imaging. [99mTc]Tc-SC-06-L1 represents a promising biomarker for imaging purine pathway-directed systems.

Major Virion Tegument Protein VP22 Targets Nuclear Matrix and Chromatin upon Entry into Cells during Productive Herpes Simplex Virus 1 Infection.

HSV-1 major tegument protein VP22 is present in multiple subcellular locations in the late stages of productive viral infection. We initially performed a detailed time course experiment and observed that VP22 was detected in nuclear and nuclear matrix fractions as early as 4 hpi. The goal was to determine the fate of virion-derived incoming VP22, and we report the following: (i) VP22 was detected in nuclear matrix fractions 1 hpi. (ii) In the presence of cycloheximide (CHX), VP22 was present in the nuclear matrix 1-6 hpi, demonstrating the stability of the protein. (iii) The nuclear matrix targeting of VP22 occurred in infected Vero, HEp-2, and human mammary epithelial (HME) cells and following synchronized infection. Based on these results, we conclude that (iv) VP22 targets the nuclear matrix and chromatin upon entry into cells during productive HSV-1 infection.

Standardization of honey as a tissue fixative for histopathology: A morphometric study

Background: Tissue fixation is a crucial step to preserve the tissues in a life-like state with minimal disruption to its cellular and chemical composition for histopathological examination. The search for an effective alternate tissue fixative to the routinely used formaldehyde has gained interest as constant exposure to formaldehyde has proven to be toxic. Honey, an organic substance with high acidity and hygroscopic nature, exhibits tissue fixative properties and has been used in the present study. The present study aimed to standardize honey as a tissue fixative for histopathology by comparing it with formalin. Materials and Methods: In vitro study Oral tissue samples of goat were fixed in 10% honey and 10% formalin solution, respectively, for 24-48 h, followed by routine tissue processing and microscopic examination of 37 slides per group. 2200 epithelial cells (1100 per group) were selected for the computer-aided morphometric image analysis (Fiji-Image J) by three observers. Cell area (CA), cell perimeter (CP), nuclear area (NA), nuclear perimeter (NP), cytoplasmic area (Cyt A), and nuclear-cytoplasmic ratio were the parameters studied. Mann-Whitney U-test (STATA/IC version 16) for inter-group comparison was done and P &lt; 0.05 was considered statistically significant. Results: The probability of epithelial cells in the honey-fixed group to have greater NA, NP, and N/C ratio was about 50%-60%. The probability of epithelial cells in formalin-fixed tissues to have greater CA, CP, and Cyt A was about 70%. Conclusion: Honey is a better nuclear fixative than formalin. Cytoplasmic shrinkage of epithelial cells should be taken into consideration while fixing tissues with honey.

The proteomic landscape of genotoxic stress-induced micronuclei

Micronuclei (MN) are induced by various genotoxic stressors and amass nuclear- and cytoplasmic-resident proteins, priming the cell for MN-driven signaling cascades. Here, we measured the proteome of micronuclear, cytoplasmic, and nuclear fractions from human cells exposed to a panel of six genotoxins, comprehensively profiling their MN protein landscape. We find that MN assemble a proteome distinct from both surrounding cytoplasm and parental nuclei, depleted of spliceosome and DNA damage repair components while enriched for a subset of the replisome. We show that the depletion of splicing machinery within transcriptionally active MN contributes to intra-MN DNA damage, a known precursor to chromothripsis. The presence of transcription machinery in MN is stress-dependent, causing a contextual induction of MN DNA damage through spliceosome deficiency. This dataset represents a unique resource detailing the global proteome of MN, guiding mechanistic studies of MN generation and MN-associated outcomes of genotoxic stress.

Proteasome localization and activity in pig brain and in vivo small molecule screening for activators.

Loss of proteasome function, proteinopathy, and proteotoxicity may cause neurodegeneration across the human lifespan in several forms of brain injury and disease. Drugs that activate brain proteasomes in vivo could thus have a broad therapeutic impact in neurology. Using pigs, a clinically relevant large animal with a functionally compartmental gyrencephalic cerebral cortex, we evaluated the localization and biochemical activity of brain proteasomes and tested the ability of small molecules to activate brain proteasomes. By Western blotting, proteasome protein subunit PSMB5 and PSMA3 levels were similar in different pig brain regions. Immunohistochemistry for PSMB5 showed localization in the cytoplasm (diffuse and particulate) and nucleus (cytoplasm < nucleus). Some PSMB5 immunoreactivity was colocalized with mitochondrial (voltage-gated anion channel and cyclophilin D) and cell death (Aven) proteins in the neuronal soma and neuropil in the neocortex of pig and human brains. In the nucleus, PSMB5 immunoreactivity was diffuse, particulate, and clustered, including perinucleolar decorations. By fluorogenic assay, proteasome chymotrypsin-like activities (CTL) in crude tissue soluble fractions were generally similar within eight different pig brain regions. Proteasome CTL activity in the hippocampus was correlated with activity in nasal mucosa biopsies. In pilot analyses of subcellular fractions of pig cerebral cortex, proteasome CTL activity was highest in the cytosol and then ~50% lower in nuclear fractions; ~15-20% of total CTL activity was in pure mitochondrial fractions. With in-gel activity assay, 26S-singly and -doubly capped proteasomes were the dominant forms in the pig cerebral cortex. With a novel in situ histochemical activity assay, MG132-inhibitable proteasome CTL activity was localized to the neuropil, as a mosaic, and to cell bodies, nuclei, and centrosome-like perinuclear satellites. In piglets treated intravenously with pyrazolone derivative and chlorpromazine over 24 h, brain proteasome CTL activity was modestly increased. This study shows that the proteasome in the pig brain has relative regional uniformity, prominent nuclear and perinuclear presence with catalytic activity, a mitochondrial association with activity, 26S-single cap dominance, and indications from small molecule systemic administration of pyrazolone derivative and chlorpromazine that brain proteasome function appears safely activable.