P53 Mutations Research Articles

Convolutional neural network and glioma genotyping: A systematic review.

e14038 Background: Gliomas are the most common primary intracranial tumors. Overall, there are 23 different glioma types, and the grading and prognosis of each type are determined by their specific mutations. Several identified mutations are IDH gene status, CDKN2A/B homozygote delegation, PTEN mutation, p53 mutation, TERT promotor mutation, H3K27M mutation, MGMT promotor methylation, trisomy 7/monozomy10, EGFR amplification, ATRX mutation, 1p/19q codeletion, and BRAF mutation. These specific mutations and genomic features can have their distinctive radiologic features seen in different magnetic resonance imaging (MRI) sequences. By using a Convolutional Neural Network (CNN) for feature extraction, the genotyping power of MRI for glioma could be increased. To address this, we systematically reviewed the use of different CNN-based models to detect the genetic context of glioma based on the MRI images. Methods: We conducted a systematic search in PubMed, Embase, Scopus, Web of Science, and Google Scholar. We included original peer-reviewed human studies (retrospective or prospective), focusing on the use of CNN in individuals with glioma. We excluded animal studies, studies with no CNN-based models, reviews, book chapters, conference abstracts, and case reports. JBI checklists were utilized for quality assessment. Results: The initial search resulted in 973 articles. after removing duplicates, 563 studies entered the screening process by title and abstract. 59 studies met our inclusion criteria (56 retrospective and 3 prospective cohort studies) with a total of 26434 glioma patients included (studies ranged from 21 – 2648 individuals). 31 studies used CNN methods only in different stages of image processing (tumor segmentation, feature extraction, image encoder) and 28 studies used CNN as a classifier and mutation predictor. ResNet was the most commonly used CNN-based model (n = 14). U-net (n = 7) and DenseNet models (n = 4) were other commonly used CNN-based models. Included studies targeted IDH status (n=44), 1p/19q codeletion (n=18), MGMT promotor methylation (n=11), ATRX mutation (n=5), TERT promotor mutation (n=5), CDKN2A/B homozygote deletion (n=3), PTEN mutation (n=3), p53 mutation (n=3), H3K27M mutation (n=2), trisomy 7/monozomy10 (n=2), EGFR amplification (n=2), and BRAF mutation (n=1). Highly severe methodological heterogeneity among these studies excluded the possibility of meta-analysis. Conclusions: Current studies have shown that, as a non-invasive method, using CNN-based models on multiple MRI sequences increases the power of early detection and prediction of glioma genetic types before pathological confirmation and has promising results. However, DL performance varies among mutations. Combining multiple DL models with clinical and radiomic features in different and larger databases can further increase the final results.

A first-in-human, phase 1, dose escalation study of SGR-2921 as monotherapy in patients with relapsed/refractory acute myeloid leukemia or myelodysplastic syndrome.

TPS6590 Background: Cell division cycle 7-related protein kinase (CDC7) is a cell cycle kinase that maintains DNA replication by phosphorylation and activation of the minichromosome maintenance protein 2 and 4 (MCMs), components of the replicative DNA helicase. Due to the CDC7's central role in maintaining replication fork integrity, chemical inhibition of CDC7 can ultimately lead to cancer cell death. SGR-2921 is an oral, small molecule inhibitor of CDC7. Preclinical studies demonstrate that SGR-2921 has potent anti-proliferative activity in AML cell lines representative of difficult to treat patient populations, agnostic of serious mutations (including those with p53 mutations), BTK resistance, and multiple prior lines of treatment. This anti-tumor activity has also been demonstrated in cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) AML models. Methods: This is a phase 1, FIH, open-label, single-agent, two-arm, dose escalation study (NCT#05961839) designed to evaluate safety and tolerability and identify the recommended phase 2 dose (RP2D) of SGR-2921 as monotherapy in subjects with relapsed or refractory (R/R) AML, high risk (HR) MDS, or very high risk (VHR) MDS. The study utilizes an accelerated titration design with single patient cohorts that transitions to a 3+3 design once a single Grade 2 event is observed. This is a multicenter global study (US, Spain and France). SGR-2921 will be administered orally, once daily, utilizing a 5-day on and 9-day off dosing schedule over a 28-day cycle. A maximum of 144 patients will be enrolled into dose escalation and exploratory cohorts. To evaluate the effect of CYP3A4 inhibition on SGR-2921 exposure, subjects will be enrolled into one of two staggered, parallel study treatment arms, according to concomitant administration with (Arm B) or without (Arm A) azole antifungals that are strong CYP3A4 inhibitors. A single dose PK run-in will be required for subjects enrolled into the first 3 cohorts of each treatment arm. Subjects will be treated at increasing doses of SGR-2921 until the maximum tolerated dose (MTD) is exceeded. A RP2D will be selected from one of the tolerable dose levels. Key study inclusion criteria include: Age ≥ 18 years of age; Life expectancy ≥ 8 weeks; Confirmed diagnosis of R/R AML or HR and VHR MDS; Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2. Key study exclusion criteria include: Active malignancies not related to AML or MDS within two years prior to the first dose or requiring ongoing treatment; active CNS leukemia; QTcF ≥470 msec. The primary objectives are to evaluate the safety and tolerability of SGR-2921 as monotherapy and to identify the RP2D. Secondary objectives include evaluating SGR-2921 pharmacokinetics and investigating preliminary antitumor activity. Clinical trial information: NCT05961839 .

Cryptolepine: A naturally derived alkaloid inhibits breast cancer progression by blocking cell cycle progression and inducing apoptosis.

e13151 Background: Triple Negative Breast cancer is an aggressive breast cancer subtype. TNBC has a more aggressive clinical course, an earlier age of beginning, a larger propensity for metastasis, and worse clinical outcomes as evidenced by a higher risk of recurrence and a shorter survival rate when compared to hormone receptor-positive or HER2-positive illness. Currently, the primary options for TNBC treatment are surgery, radiation, and chemotherapy. These treatments, however, remain ineffective due to recurrence. However, given that p53 mutations have been identified in more than 60–88% of TNBC, translating p53 into the clinical situation is particularly important in TNBC. Given the scope that some natural drugs can be used as specifically targeting prospective therapeutic in TNBC and to sensitize this aggressive malignancy while reducing side effects. In this study, we screened and evaluated the therapeutic potential of CRP in TNBC in-vitro models being an anti-malarial drug it could be repurposed as an anti-cancer therapeutic in TNBC. Moreover, the cytotoxicity activity of cryptolepine to TNBC cells and a detailed anti-tumor mechanism in mutant P53 has not been reported. Methods: MTT assays were used to examine the cytotoxicity and cell viability activity of Cryptolepine in TNBC, non-TNBC T47D and MCF-7 and non-malignant MCF10A cells. Scratch wound and clonogenic assay was used to evaluate cryptolepine’s effect on migration and colony forming ability of TNBC cells. Flow cytometry, MMP and DAPI was used to assess cell cycle arrest and cell apoptosis. The expression of proteins was detected by western blots. The differential expression of RNAs was evaluated by RT-PCR and the interaction between P53 and drug was evaluated computationally using in-silico approach and in-vitro using ChIP assay. Results: In this study, we found that cryptolepine has more preferential cytotoxicity in TNBC than non-TNBC cells. Notably, our studies revealed the mechanism that cryptolepine can induce intrinsic apoptosis and inhibit migration, colony formation ability, induce cell cycle arrest by inducing conformational change in the mutant P53 thereby increasing its DNA binding ability and also inducing its own transcriptional activation to synthesize new P53 protein and hence activating its tumor suppressing potential significantly. Conclusions: Our study revealed that CRP significantly reduced the proliferation, migration and colony forming ability of TNBC cells lines. Moreover, it was revealed that CRP induces cell cycle arrest and apoptosis by activating mutant P53 and enhancing its DNA binding ability to induce its tumor suppressing ability.

Second primary squamous cell cancers in the HPV de-escalation Quarterback Trials.

e18049 Background: Patients with HPV oropharyngeal cancer (HPVOPC) have a cure rate approaching 90%, and will live for decades with the sequelae of therapy. Trials evaluating treatments for HPVOPC select patients by p16 status rather than using more accurate molecular testing; a fraction of these patients, approaching 5%, are HPV16 negative. Recurrent cancers are often not tested molecularly and may not be tested for p16. Applying molecular diagnostics for HPV at diagnosis and relapse can avoid significant mis-assignment, mistreatment, and inaccurate results in clinical trials. We reviewed and report results from the Quarterback Trials (QT) where molecular testing confirmed HPV status at diagnosis and recurrence. Methods: Patients entered on the QT were required to have < 20 py smoking history, not be active smokers, have non-metastatic locally advanced disease, and have a molecularly confirmed HPV status, including genotype (PCR based DNA Sequencing). Subjects were treated with TPF chemotherapy for 3 cycles and patients with an adequate response were eligible for de-escalation of chemoradiotherapy (CRT) to 5600 cGy (RD). The first 20 patients were randomized to standard dose (SD) 7000 cGy (8) or RD (12). Patients who withdrew from the study or had an inadequate response to TPF, were treated with SD. Patients were monitored for recurrent disease by routine surveillance with physical examination and PET scan. Recurrences were confirmed with tissue biopsy. We performed a retrospective analysis of 2nd in-field primaries (SP) and compared them to local regional recurrences (LRF) in the entire eligible population. Results: 62 patients were consented on to the QTs. 2 patients failed screening and are not considered any further. 14 patients received 7000 cGy: 8/14 were randomized to SD, 5/14 had an inadequate response to TPF and 1/14 patient withdrew consent. One patient randomized to SD withdrew consent and stopped CRT at 5200cGy. There were 7 HPV+ LRF: (1 SD and 6 RD); and 4 molecularly documented in-field non-HPV SP squamous cell cancers: 2/14 SD (14%) and 2/46 RD (4%). 1 of 4 SP tumors was p16+; all were molecularly negative for HPV and had documented p53 mutations. Median time to LRF was 8 mo. (4-49) and 66 mo. (35-84) for SP. Median survival after LRF is 11 (4-72+) and after SP 18+ (3-36+). 4/11 (36%) of post treatment local regional squamous cancer events were not HPV related. Conclusions: Non-HPV SP SCC were not rare events in this documented HPV+, non-smoking population. SP were more common in the SD than the RD treated patients suggesting an RT dose dependency and causality, although other biologic explanations are possible. SP will increase and be a major cause of mortality in this population indicating a need for awareness during surveillance. p16 is inaccurate for determining HPV16 status at diagnosis and recurrence in HPV critical clinical trials and in-field cancer events should be molecularly assessed to determine if they are LRF or SP.

Neoantigen-specific stimulation of tumor-infiltrating lymphocytes enables effective TCR isolation and expansion while preserving stem-like memory phenotypes

BackgroundTumor-infiltrating lymphocytes (TILs) targeting neoantigens can effectively treat a selected set of metastatic solid cancers. However, harnessing TILs for cancer treatments remains challenging because neoantigen-reactive T cells are often rare...

Impact of Oncogenic Changes in p53 and KRAS on Macropinocytosis and Ferroptosis in Colon Cancer Cells and Anticancer Efficacy of Niclosamide with Differential Effects on These Two Processes.

Mutations in p53 and KRAS are seen in most cases of colon cancer. The impact of these mutations on signaling pathways related to cancer growth has been studied in depth, but relatively less is known on their effects on amino acid transporters in cancer cells. This represents a significant knowledge gap because amino acid nutrition in cancer cells profoundly influences macropinocytosis and ferroptosis, two processes with opposing effects on tumor growth. Here, we used isogenic colon cancer cell lines to investigate the effects of p53 deletion and KRAS activation on two amino acid transporters relevant to macropinocytosis (SLC38A5) and ferroptosis (SLC7A11). Our studies show that the predominant effect of p53 deletion is to induce SLC7A11 with the resultant potentiation of antioxidant machinery and protection of cancer cells from ferroptosis, whereas KRAS activation induces not only SLC7A11 but also SLC38A5, thus offering protection from ferroptosis as well as improving amino acid nutrition in cancer cells via accelerated macropinocytosis. Niclosamide, an FDA-approved anti-helminthic, blocks the functions of SLC7A11 and SLC38A5, thus inducing ferroptosis and suppressing macropinocytosis, with the resultant effective reversal of tumor-promoting actions of oncogenic changes in p53 and KRAS. These findings underscore the potential of this drug in colon cancer treatment.

Role of peritumoral tissue analysis in predicting characteristics of hepatocellular carcinoma using ultrasound-based radiomics

Predicting the biological characteristics of hepatocellular carcinoma (HCC) is essential for personalized treatment. This study explored the role of ultrasound-based radiomics of peritumoral tissues for predicting HCC features, focusing on differentiation, cytokeratin 7 (CK7) and Ki67 expression, and p53 mutation status. A cohort of 153 patients with HCC underwent ultrasound examinations and radiomics features were extracted from peritumoral tissues. Subgroups were formed based on HCC characteristics. Predictive modeling was carried out using the XGBOOST algorithm in the differentiation subgroup, logistic regression in the CK7 and Ki67 expression subgroups, and support vector machine learning in the p53 mutation status subgroups. The predictive models demonstrated robust performance, with areas under the curves of 0.815 (0.683–0.948) in the differentiation subgroup, 0.922 (0.785–1) in the CK7 subgroup, 0.762 (0.618–0.906) in the Ki67 subgroup, and 0.849 (0.667–1) in the p53 mutation status subgroup. Confusion matrices and waterfall plots highlighted the good performance of the models. Comprehensive evaluation was carried out using SHapley Additive exPlanations plots, which revealed notable contributions from wavelet filter features. This study highlights the potential of ultrasound-based radiomics, specifically the importance of peritumoral tissue analysis, for predicting HCC characteristics. The results warrant further validation of peritumoral tissue radiomics in larger, multicenter studies.

Exploring novel approaches in the systemic therapy of low-grade serous carcinoma of the ovary: a literature review.

By presenting a comprehensive analysis of low-grade serous carcinomas (LGSCs), a subset of epithelial ovarian cancers, this review delves into their distinct molecular characteristics, clinicopathological features and systemic therapy options, emphasizing their differences from high-grade serous carcinomas (HGSCs). Notably, LGSCs exhibit prevalent RAS/RAF/MEK/MAPK pathway activation, KRAS and BRAF mutations, and infrequent p53 mutations. While chemotherapy is commonly employed, LGSCs display lower responsiveness compared to HGSCs. Hormone therapy, particularly endocrine maintenance therapy, is explored due to the higher estrogen receptor expression. Novel therapeutic approaches involving CDK4/6 inhibitors, MEK inhibitors, and antiangiogenic agents like bevacizumab are also investigated. Ongoing clinical trials are striving to enhance LGSC treatment strategies, offering valuable insights for future therapeutic advancements in this challenging ovarian cancer subtype.

The frequency and prognostic role of P53 and P16 immunoexpression in primary ovarian mucinous tumors

BackgroundPrimary ovarian mucinous tumors are uncommon. Factors leading to invasive progression and metastatic disease have not been fully delineated yet. The aim of this study is to determine the rates of p53 and p16 immunoexpressions in primary ovarian mucinous tumors, to investigate their relationship with clinicopathologic factors and their impact on prognosis and survival. MethodsSeventy-eight primary ovarian mucinous tumors (30 mucinous cystadenomas, 30 mucinous borderline tumors (MBOT), 18 mucinous carcinomas (MOC)) were evaluated immunohistochemically with p53 and p16 staining. The demographic, clinicopathological data, and postoperative follow-up findings of the patients were analyzed. ResultsMutation-type p53 staining was present in 1/30 (3.3 %) cystadenoma, 10/30 (33.3 %) MBOT and 9/18 (50 %) MOC (p = 0.001). p16 overexpression was detected in 3/30 (10.0 %) MBOT and 5/18 (27.8 %) MOC, but not in any cystadenoma (p = 0.04). The frequency of mutation-type p53 staining in MBOTs with microinvasion was higher (71.4 %) than in those without (28.6 %, p = 0.026). The frequencies of p16 or p53 mutations were similar in MBOTs with and without intraepithelial carcinoma, or mural nodule (p > 0.05). In MOCs with ovarian surface involvement, mutation-type p53 staining was detected in 66.7 % (6/9) and p16 overexpression in 55.6 % (5/9) of the cases. A significant difference was found between MOCs with or without ovarian surface involvement regarding the frequency of p16 overexpression (p = 0.029). Any relationship was not detected between survival and p53 and p16 expression in MOCs (p > 0.05). Conclusionp53 and p16 mutation rates were higher in MOCs compared to mucinous cystadenomas and MBOTs and suggest a relevant role in the development of primary ovarian mucinous carcinoma, however further studies are needed in this regard.

Clinical and Immunologic Characteristics of Colorectal Cancer Tumors Expressing LY6G6D.

The identification of targets that are expressed on the cell membrane is a main goal in cancer research. The Lymphocyte Antigen 6 Family Member G6D (LY6G6D) gene codes for a protein that is mainly present on the surface of colorectal cancer (CRC) cells. Therapeutic strategies against this protein like the development of T cell engagers (TCE) are currently in the early clinical stage. In the present work, we interrogated public genomic datasets including TCGA to evaluate the genomic and immunologic cell profile present in tumors with high expression of LY6G6D. We used data from TCGA, among others, and the Tumor Immune Estimation Resource (TIMER2.0) platform for immune cell estimations and Spearman correlation tests. LY6G6D expression was exclusively present in CRC, particularly in the microsatellite stable (MSS) subtype, and was associated with left-side tumors and the canonical genomic subgroup. Tumors with mutations of APC and p53 expressed elevated levels of LY6G6D. This protein was expressed in tumors with an inert immune microenvironment with an absence of immune cells and co-inhibitory molecules. In conclusion, we described clinical, genomic and immune-pathologic characteristics that can be used to optimize the clinical development of agents against this target. Future studies should be performed to confirm these findings and potentially explore the suggested clinical development options.

Abstract PO2-24-08: GD3 Synthase is a Master Regulator of Wild-Type p53–Mediated Apoptosis and Mutant p53–Mediated Tumorigenesis

Abstract The tumor suppressor protein p53 is essential for maintaining genomic stability and regulating cellular responses to stress. TP53 mutations are common in breast cancer (BC) and other malignancies. We previously showed that ganglioside GD2 identifies BC stem-like cells (BCSCs) and that GD3 synthase (GD3S/ST8SIA1) is upregulated in breast tumors with TP53 mutations. Here, we demonstrate the direct involvement of p53 in the transcriptional regulation of GD3S in the GD2 biosynthesis pathway. Our results uncover a novel role of GD3S in inhibiting p53-mediated apoptosis and promoting mutant p53–induced tumor initiation. To investigate the p53-mediated regulation of GD3S expression, we used the TCGA and METABRIC datasets and examined GD3S mRNA expression in breast tumors with different p53 mutation status. GD3S expression was significantly upregulated in BC patients with hotspot (HS) p53 mutations compared to those with wild-type (WT) p53 or non-HS p53 mutations (P< 0.0001). Immuno-histochemical analysis of GD3S and p53 in FFPE primary tumor tissues from BC patients (n=84) with varying p53 expression status demonstrated that patients with HS p53 mutations had higher histological scores for GD3S than did patients with WT p53 (P< 0.0001) or non-HS p53 mutations (P=0.009). GD3S and p53 expression were significantly positively correlated in patients with HS p53 mutations (r=0.735; P=0.006) but not in patients with WT p53 (r=–0.09) or non-HS p53 mutations (r=0.14). Consistent with these patient data, BC cells harboring HS p53 mutations had significantly upregulated and positively correlated expressions of GD3S and p53 (n=8; r=0.85). Moreover, compared to those with WT p53, the cells with HS p53 mutations had substantially greater populations of GD2+ BCSCs (P=0.02) and GD3+ BCSCs (P=0.01). Subsequently, we investigated the regulatory role of p53 in the GD2 biosynthetic pathway by stabilizing WT p53 expression by nutlin-3a treatment in 4 BC cell lines and suppressing the expression of HS p53 mutants by p53 knockdown in their respective cell lines (n=4). In cell lines with WT p53, nutlin-3a significantly decreased GD3S expression and GD2 levels (P< 0.05 and P< 0.0001, respectively), suggesting that WT p53 inhibits GD3S expression. In cell lines with p53 mutations, p53 knockdown significantly inhibited GD3S expression. In both cells with WT p53 (MCF7 and ZR751) and cells with HS p53 mutations (Hs578T and BT549), the stable overexpression of GD3S effectively suppressed apoptosis even when WT p53 was stabilized or HS p53 mutant expression was depleted. Consistent with these results, in mice bearing MCF7 cell–derived xenografts, the overexpression of GD3S counteracted the effect of stabilized WT p53–mediated apoptosis and facilitated tumor growth (P< 0.0001). The results of a promoter-luciferase reporter assay demonstrated that nutlin-3a reduced GD3S promoter activity in a dose-dependent manner in MCF7 and ZR751 cells (P< 0.0001), whereas doxycycline (1µM) significantly reduced GD3S promoter activity in Hs578T and BT549 cells with inducible p53 knockdown (P< 0.001). ChIP-qPCR analysis confirmed specific enrichment of WT p53 at the 300-bp upstream regions and additional enrichment of HS p53 mutants at the downstream regions of the GD3S promoter, indicating that WT p53 and HS p53 mutations have distinct promoter regulation patterns. In summary, our study reveals that GD3S has a previously unknown anti-apoptotic function in BC, in that it helps attenuate p53-mediated apoptosis while activating tumor-promoting pathways that operate independently of p53. Citation Format: Vivek Anand, FOUAD EL-DANA, JENNY BORGMAN, MICHAEL ANDREEFF, Venkata Lokesh Battula. GD3 Synthase is a Master Regulator of Wild-Type p53–Mediated Apoptosis and Mutant p53–Mediated Tumorigenesis [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 PO2-24-08.

Abstract PO4-28-07: SLC26A9 promotes triple-negative breast cancer progression by regulating lipid metabolism

Abstract Background: The disturbance of lipid metabolism in the microenvironment plays an important role in the occurrence and development of triple-negative breast cancer(TNBC). SLC26A9, a member of the SLC26A family of anion transporters, is involved in breast oncogenesis. However, the effect of SLC26A9 in triple-negative breast cancer on lipid metabolism in the tumor microenvironment remains unclear. Methods: Bioinformatics, tissue microarrays and TNBC cell lines were used to detect the expression of SLC26A9 and its clinical significance. By altering the expression of SLC26A9 gene in TNBC cells, the effects of SLC26A9 on the regulation of lipid metabolism, cell biological behavior and its related molecular mechanisms in the TNBC microenvironment were explored using adoptive staining techniques, flow cytometric analysis and animal models. Results: We found by tissue microarray (TNBC=105 cases, Nor=67 cases) that the expression of SLC26A9 was significantly up-regulated in BC compared to paracancerous tissues, where SLC26A9 expression was higher in TNBC, and the same results were obtained in BC cell lines. Secondly, we found that SCL26A9 was positively correlated with lipid metabolism status in TNBC microenvironment and possessed a close association with P53 mutation by analyzing GEO and TCGA databases. Therefore, we used two cell lines (MDA-MB-231, MDA-MB-468) in which SCL26A9 was highly expressed in TNBC cell lines. It was demonstrated by oil red O staining and lipid fluorescence staining that knockdown/silencing of SLC26A9 diminished the ability of MDA-MB-231 and MDA-MB-468 cells to uptake and utilize lipids, especially for metabolites such as neutral lipids: triglycerides, lipid droplets, and steroidal substances. Then we demonstrated by using fatty acid flow cytometric analysis that knockdown/silencing of SLC26A9 significantly reduced the utilization and production of fatty acids in MDA-MB-231 and MDA-MB-468 cells, which are the key metabolic indicators of cancer cells as well as important energy-providing substances for cancer progression. Therefore, we further verified functionally that cell proliferation, migration, invasion and anti-apoptosis were significantly inhibited in in vitro after knockdown/silencing of SLC26A9, and in vivo tumorigenesis was significantly inhibited in BALB/c nude mice in in vivo. In addition, the expression of markers of lipid metabolic activity (FASN, ACLY) was reduced after knockdown/silencing of SLC26A9 in MDA-MB-231 cells by Western Blot, and the reduced expression of FASN and ACLY mainly inhibited the ab initio synthesis, uptake and utilization of fatty acids in TNBC cells, which in turn regulated the proliferation and invasion of TNBC. Mechanistically, SLC26A9 silencing/knockdown inhibited the synthesis, uptake, and utilization of multiple metabolites of lipids in TNBC, which combined with the TCGA database results revealed the activation of the key signaling pathway, the JAK-STAT3 signaling pathway, to promote the progression of TNBC. Conclusion(s): SLC26A9 is involved in the disturbance of lipid metabolism in the TNBC microenvironment and regulates the progression of TNBC. The search for new SLC26A9 inhibitors is expected to provide a new direction for the treatment of TNBC, but the exact molecular mechanisms need to be further explored. SLC26A9 upregulation in TNBC leads to a poor prognosis by referencing lipid metabolism in the TNBC microenvironment Wench. SLC26A9 is involved in lipid metabolism disorders and cell biological functions in the TNBC microenvironment in vivo. SLC26A9 is involved in disordered lipid metabolism in the TNBC microenvironment. Citation Format: Yingming Zhou, Hu Wang, Zhengxing Zhou, Xuemei Liu, Biguang Tuo, Taolang Li. SLC26A9 promotes triple-negative breast cancer progression by regulating lipid metabolism [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 PO4-28-07.

Abstract PO2-13-05: Deciphering pregnancy-associated breast cancer: distinctive molecular profile and clinical implications from GEICAM/2017-07 EMBARCAM study

Abstract Background: Pregnancy-Associated Breast Cancer (PABC) is defined as BC diagnosed during pregnancy, breastfeeding, or within the first year postpartum. This challenging entity has a distinct biology and worst prognosis and presents an increased risk for metastasis and death compared to non-PABC patients. Identification of molecular pathways that define this malignancy is crucial to explain its biological characteristics and potential association with pregnancy as well as serve to identify new biomarkers with preventive and clinical implications. This study assesses the gene expression profile of a PABC cohort from the Registry Study of Pregnancy and Breast Cancer (GEICAM/2017-07 EMBARCAM study, NCT04603820) to identify distinct molecular signatures and altered pathways for this entity. Methods: This was a multicenter, observational and ambispective age-matched cohort of PABC patients (n=46) and non-PABC patients (n=49). We analyzed the expression of 776 genes involved in 23 key breast cancer pathways, using the nCounter® Breast Cancer 360™ Panel (NanoString Technologies) on BC tumor samples, including molecular subtypes by PAM50 gene signature. Associations between individual differential genes and epidemiological and clinical features of these patients were explored. Normalized differential expression values were log2-transformed for statistical analysis in nSolver Software (NanoString Technologies). P-values were adjusted within each gene/signature and on the grouping variable level difference t-test using the Benjamini and Yekutieli False Discovery Rate (FDR) adjustment. Results: PABC patients’ clinical subtypes were distributed as 43,5% HR-positive/HER2-negative, 17,4% HER2-positive and 39,1% triple negative BC. These patients reported higher family history of BC/ovarian cancer compared to non-PABC (52.17% vs 26.53%; p=0.0124). Differential gene expression showed distinct molecular profiles in PABC and non-PABC patients: significantly genes enrichment involved in cell proliferation and p53 signature for PABC patients and higher expression of apoptosis, TGF-β, and PTEN signatures for non-PABC (adj p< 0.05). Furthermore, CDK4 expression signature (adj p=0.124) and DNA damage repair signatures Homologous Recombination Deficiency (HDR) (adj p=0.083) and BRCAness (adj p=0.220) were also upregulated in PABC tumors. The most significantly upregulated genes in PABC patients (CCNA2, DEPDC1, FAM83D, CDC20, CDKN3, TRIP13, TTK, MAD2L1, KIF2C, and UBE2C) (adj p< 0.05) were involved in cell cycle regulation and DNA damage repair. PABC basal-like tumors were found to be significantly more prevalent than non-PABC, as per the PAM50 classification (45.7% vs 20.4%; p=0.020). Interestingly, basal-like PABC showed higher expression of ESR1 than basal-like non-PABC (logFC=1.486; p=0.022). In contrast, luminal A PABC tumors exhibited lower ESR1 expression vs non-PABC (logFC=-1.5; p=0.021). Additionally, HER2-enriched PABC tumors displayed lower B7-H3/CD276 expression compared to HER2-enriched non-PABC (adj p=0.031). Conclusions: Our study shows that PABC is potentially a clinical and molecular different entity with predominance of the basal-like subtype. Moreover, our results suggest the activation of oncogenic pathways related to cell proliferation, DNA damage repair and p53 mutations which may lead to a clinically more aggressive phenotype for PABC patients. Likewise, the enrichment of BRCAness and HRD signatures found in PABC patients in our study may suggest an increased genetic instability due to a breakdown in the DNA damage repair. These findings may be clinically relevant and translate to new treatment options in PABC patients, who may benefit from therapies targeting DNA repair or cell-cycle checkpoints, such as PARP inhibitors. Citation Format: Juan de la Haba-Rodríguez, Regina Peña, Marina Pollan, Yolanda Jerez Gilarranz, Jose Ponce, Antonio Fernández Aramburu, Blanca Cantos, Ana Santaballa Bertrán, Elena Galve, María Eva Pérez, Susana de la Cruz, María Helena López-Ceballos, Yolanda Fernández, Fernando Moreno, Sonia González, Manuel Ruíz - Borrego, Isabel Blancas, José L Alonso-Romero, Álvaro Jiménez-Arranz, Raúl Rincón, Silvia Guil, Alejandra Díaz-Chacón, Rosalía Caballero, Begoña Bermejo, Angel Guerrero. Deciphering pregnancy-associated breast cancer: distinctive molecular profile and clinical implications from GEICAM/2017-07 EMBARCAM study [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 PO2-13-05.

Age-specific induction of mutant p53 drives clonal hematopoiesis and acute myeloid leukemia in adult mice

The investigation of the mechanisms behind p53 mutations in acute myeloid leukemia (AML) has been limited by the lack of suitable mouse models, which historically have resulted in lymphoma rather than leukemia. This study introduces two new AML mouse models. One model induces mutant p53 and Mdm2 haploinsufficiency in early development, showing the role of Mdm2 in myeloid-biased hematopoiesis and AML predisposition, independent of p53. The second model mimics clonal hematopoiesis by inducing mutant p53 in adult hematopoietic stem cells, demonstrating that the timing of p53 mutation determines AML vs. lymphoma development. In this context, age-related changes in hematopoietic stem cells (HSCs) collaborate with mutant p53 to predispose toward myeloid transformation rather than lymphoma development. Our study unveils new insights into the cooperative impact of HSC age, Trp53 mutations, and Mdm2 haploinsufficiency on clonal hematopoiesis and the development of myeloid malignancies.

Significant differences in p53 and BRAFV600 mutations among histological type of thyroid carcinoma in Indonesia

Significant differences in p53 and BRAFV600 mutations among histological type of thyroid carcinoma in Indonesia

ZN-2: A natural product small molecule stabilizes p53Y220C to restore p53 mutation – A high-throughput virtual screening approach

ZN-2: A natural product small molecule stabilizes p53Y220C to restore p53 mutation – A high-throughput virtual screening approach

Cell-free DNA bearing p53 mutation (R248) as non-invasive biomarker in patients with head and neck squamous cell carcinoma

Cell-free DNA bearing p53 mutation (R248) as non-invasive biomarker in patients with head and neck squamous cell carcinoma

Reconnaissance of Allostery via the Restoration of Native p53 DNA-Binding Domain Dynamics in Y220C Mutant p53 Tumor Suppressor Protein.

Allosteric regulation of protein dynamics infers a long-range deliberate propagation of information via micro- and macroscale interactions. The Y220C structural mutant is one of the most frequent cancerous p53 mutants. The mutation is distally located from the DNA-binding site of the p53 DNA-binding domain yet causes changes in DNA recognition. This system presents a unique opportunity to examine the allosteric control of mutated proteins under a drug design paradigm. We focus on the key case study of p53 Y220C mutation restoration by a series of new compounds suggested to have Y220C reactivation properties in comparison to our previous findings on the restorative potential of PK11000, a compound studied extensively for reactivation in vitro and in vivo. Previously, we implemented all-atom molecular dynamics (MD) simulations and our lab's techniques of MD-Sectors and MD-Markov state models on the wild type, the Y220C mutant, and Y220C with PK11000 to characterize the effector's restorative properties in terms of conformational dynamics and hydrogen bonding. In this study, we turn to probing the effects made by docking the battery of a new but less well-tested set of aminobenzothiazole derivative compounds reported by Baud et al., which show promise of Y220C rescue. We find that while complete and precise reconstitution of p53 WT molecular dynamics may not be observed as was the case with PK11000, dispersed local reconstitution of loop dynamics provides evidence of rescuing effects by aminobenzothiazole derivative N,2-dihydroxy-3,5-diiodo-4-(1H-pyrrol-1-yl)benzamide, Effector 22, like what we observed for PK11000. Generalizable insights into the mutation and allosteric reactivation of p53 by various effectors by reconstitution of WT dynamics observed in statistical conformational ensemble analysis and network inference are discussed, considering the development of allosteric drug design rooted in first principles.

Extracellular vesicles of Bifidobacterium longum reverse the acquired carboplatin resistance in ovarian cancer cells via p53 phosphorylation on Ser15.

We previously found that the relative abundance of Bifidobacterium was increased after chemotherapy; however, the role of Bifidobacterium longum in chemotherapeutic drug resistance in ovarian cancer (OVC) remains unclear. This study aimed to understand the potential effects and mechanism of B. longum extracellular vesicles (B. longum-EVs) on carboplatin (CBP) resistance in OVC. Eight normal and 11 ovarian tissues were collected and the expression of B. longum genomic DNA and its association with acquired CBP resistance in OVC patients was determined. After isolating EVs by ultracentrifugation from B. longum (ATCC 15707), CBP-resistant A2780 cells were treated with PBS, CBP, B. longum-EVs, or CBP + B. longum-EVs, and subsequently analyzed by CCK-8, Edu staining, Annexin V/PI double staining, wound healing, and Transwell assays to detect cell viability, proliferation, apoptosis, migration, and invasion, respectively. MRP1, ATP7A, ATP7B, and p53 expression as well as p53 phosphorylation were measured by western blot analysis. S15A mutation of p53 was assessed to examine the potential role of p53 Ser15 phosphorylation in CBP-resistant OVC. B. longum levels were elevated and positively associated with CBP resistance in OVC patients. Only high concentrations of B. longum-EVs attenuated A2780 cell proliferation, apoptosis, migration, and invasion. B. longum-EVs exposure significantly enhanced the sensitivity of CBP-resistant A2780 cells to CBP and decreased the expression of drug resistance-related proteins. The effect of B. longum-EVs on reversing CBP resistance was completely inhibited by S15A mutation of p53. B. longum-EVs enhanced the sensitivity of OVC cells to CBP through p53 phosphorylation on Ser15.

The Relationship of Microsatellite Instability with BRAF and p53 Mutations and Histopathological Parameters in Colorectal Adenocarcinoma.

This study aims to elucidate the associations between microsatellite instability (MSI) status, BRAF mutation, and p53 reactions with pathological parameters and survival outcomes in colorectal carcinoma. MutL homologous 1 (MLH1), Postmeiotic segregation increased 2 (PMS2), MutS homologous 2 (MSH2), MutS homologous 6 (MSH6), BRAF, and p53 antibodies were performed on 130 adenocarcinoma samples, including 65 from the right colon and 65 from the left colon. The relationships of MSI status with BRAF mutation, p53 reaction, clinical and pathological parameters, and survival times were statistically analyzed. A statistically significant relationship was found between MSI and right colon localization, tumor size, histological grade, intraepithelial tumor-infiltrating lymphocytes, Crohn-like lymphocytic reaction, expansive growth pattern, and BRAF mutation (p < 0.05). No significant correlation was found between MSI status and the disease-free or overall survival times (p > 0.05). In colorectal adenocarcinoma, MSI and BRAF mutation are associated with parameters, indicating the host immune response and prognostic histopathological parameters, including tumor size and histological grade. The evaluation of MSI status and BRAF mutation can be particularly informative for predicting the prognosis and guiding the treatment management in poorly differentiated colorectal adenocarcinoma. Understanding the mechanisms of molecular carcinogenesis in colorectal carcinoma and organizing treatment algorithms based on molecular foundations will increase the success of the treatment.