Cell Proliferation-related Genes Research Articles

DEPTH2 score was associated with cell proliferation and immune cell infiltrations but not with systemic treatment response in breast cancer.

Intratumoral genomic heterogeneity (ITGH), the existence of genotypic and phenotypic variation within an individual tumor, is known to be a key mechanism in treatment resistance. Deviating gene Expression Profiling Tumor Heterogeneity 2 (DEPTH2) algorithm was developed to estimate ITGH using solely RNA expression data unlike the others that require both DNA- and RNA-expression data. Total of 6,500 breast cancer patients from multiple independent cohorts were analyzed using DEPTH2. High DEPTH2 score patients were associated with worse overall survival consistently across all subtypes in METABRIC, but not in TCGA and SCAN-B cohort. Higher DEPTH2 score was linked to increased cell proliferation, as evidenced by elevated Nottingham histological grades and Ki67 gene expression, as well as enrichment of the cell proliferation-related gene sets, and immune cell infiltrations. DEPTH2 score was significantly higher in triple negative breast cancer among the subtypes but did not reflect with lymph node and distal metastasis. DEPTH2 scores decreased in two but showed no change in another two cohorts after neoadjuvant chemotherapy (NAC). DEPTH2 score was not associated with pathologic complete response after NAC in any subtypes across 3 cohorts. DEPTH2 score may not capture the entire biological aspects of ITGH in breast cancer patients.

Enhanced cancer cell proliferation and aggressive phenotype counterbalance in breast cancer with high BRCA1 gene expression.

While comprehensive research exists on the mutation of the DNA repair gene BRCA1, limited information is available regarding the clinical significance of BRCA1 gene expression. Given that cancer cell proliferation is aggrevated by DNA repair, we hypothesized that high BRCA1 gene expression breast cancer (BC) might be linked with aggressive tumor biology and poor clinical outcomes. The cohorts: The Cancer Genome Atlas (TCGA, n = 1069), METABRIC (n = 1903), and SCAN-B (n = 3273) were utilzed to obtain data of 6245 BC patients. BC patients without BRCA1 mutation exhibited higher BRCA1 expression, which was associated with DNA repair functionality. However, no such correlation was observed with BRCA2 expression. The association of high BRCA1 expression with cancer cell proliferation was evidenced by significant enrichment of cell proliferation-related gene sets, higher histological grade, and proliferation score. Furthermore, increased levels of homologous recombination deficiency, intratumoral heterogeneity, and altered fractions were associated with high BRCA1 expression. Moreover, BC with high BRCA1 expression exhibited reduced infiltration of dendritic cells and CD8 T-cells, while showing increased infiltration of Th1 cells. Surprisingly, BRCA1 expression was not associated with the survival of BC irrespective of the subtypes. Conversely, BC with low BRCA1 expression enriched cancer aggravating pathway gene sets, such as Cancer Stem Cell-related signaling (NOTCH and HEDGEHOG), Angiogenesis, Epithelial-Mesenchymal Transition, Inflammatory Response, and TGF-beta signaling. Despite being linked to heightened proliferation of cancer cells and unassertive phenotype, BRCA1 expression did not show any association with survival in BC.

Splicing dysregulation in glioblastoma alters the function of cell migration-related genes.

Glioblastoma (GBM) has a poor prognosis with a high recurrence and low survival rate. Previous RNA-seq analyses have revealed that alternative splicing (AS) plays a role in GBM progression. Here, we present a novel AS analysis method (Semi-Q) and describe its use to identify GBM-specific AS events. We analyzed RNA-seq data from normal brain (NB), normal human astrocytes (NHAs) and GBM samples, and found that comparison between NHA and GBM was especially informative. Importantly, this analysis revealed that genes encoding cell migration-related proteins, including filamins (FLNs) and actinins (ACTNs), were among those most affected by differential AS. Functional assays revealed that dysregulated AS of FLNA, B and C transcripts produced protein isoforms that not only altered transcription of cell proliferation-related genes but also led to enhanced cell migration, resistance to cell death and/or mitochondrial respiratory function, while a dysregulated AS isoform of ACTN4 enhanced cell migration. Together, our results indicate that cell migration and actin cytoskeleton-related genes are differentially regulated by AS in GBM, supporting a role for AS in facilitating tumor growth and invasiveness.

Chemical profiling, cytotoxicity and mode of action of sea urchin Echinometra mathaei exoskeleton extract in HepG2 cancer cell line

Marine organisms contain several secondary metabolites with potent biological and pharma­cological activities. This research aimed to study the cytotoxicity and mechanism of action of methanol (MeOH) extract from the exoskeleton (shell and spines) of the sea urchin Echinometra Mathaei on human liver cancer cell line (HepG2). E. mathaei was collected from the intertidal zone of the Red Sea, Al-Ain Al-Sokhna, Egypt. HepG2 cells were treated with the MeOH extract for 24 and 48 hours to assess the cytotoxic activity and the potential molecular mechanisms. The expression levels of apoptosis-, autophagy-, and cell proliferation-related genes and/or proteins were measured. In addition, metabolomic profiling of the extract was performed by gas chromatography-mass spectrometry (GC-MS) analysis. The extract displayed cytotoxic activity on the liver cancer cells (IC50 29.47 and 14.97 µg/ml at 24 and 48 hours, respectively). It induced apoptosis, autophagy and inhibited cell proliferation of HepG2 cells. The metabolomic profiling showed that the extract is rich in fatty acids. These results demonstrated that the exoskeleton MeOH extract of E. mathaei induced apoptosis in HepG2 cells, confirming its cytotoxic effect. Therefore, a thorough investigation of its molecular target and structure is necessary to develop novel anticancer therapeutics from marine Sea urchins.

Alpha-1-antitrypsin improves anastomotic healing in intestinal epithelial cells model.

Intestinal anastomosis is a routine procedure in pediatric surgery, with leakage being a significantcomplication. Human alpha1-antitrypsin (AAT), whose physiological serum concentrations range from 0.9-2.0 mg/ml,is known to accelerate wound healing and stimulate the expression of cell proliferation-related genes. Wehypothesized that AAT might enhance anastomotic healing. In a monolayer of non-tumorigenic HIEC-6 epithelial cells derived from fetal intestine a scratch wascreated. Standard medium without (control) or with AAT (0.5 and 1 mg/ml) was added. Cells were observed using aLife-Cell Imaging System. Cell proliferation was assessed, and the expression of proliferation-related genes wasmeasured by qRT-PCR. In the presence of AAT, the scratch closed significantly faster. Cells treated with 1 mg/ml AAT showed 53%repopulation after 8 h and 97% after 18 h, while control cells showed 24% and 60% repopulation, respectively(p < 0.02). The treatment with AAT induced HIEC-6-cell proliferation and significantly increased the mRNA-expressionof CDKN1A, CDKN2A, ANGPTL4, WNT3 and COL3A1 genes. AAT did not change the mRNA-expression of CXCL8 butdecreased levels of IL-8 as compared to controls. At physiological concentrations AAT accelerates the confluence of intestinal cells and increases cellproliferation. The local administration of AAT may bear therapeutic potential to improve anastomotic healing.

5-Azacytidine treatment inhibits the development of lung cancer models via epigenetic reprogramming and activation of cellular pathways with anti-tumor activity.

Non-small cell lung cancer (NSCLC) treatment is challenged by late detection and limited therapeutic options. Aberrant DNA methylation, a common epigenetic alteration in NSCLC, offers new therapeutic avenues. This study aims to evaluate the combined effects of 5-Azacytidine (5-Aza), an epigenetic modifier, and ionizing radiation (IR) on NSCLC, exploring the underlying molecular mechanisms and therapeutic potential. In this study, we examined the effects of 5-Aza combined with IR in both in vitro and in vivo models of NSCLC. Five human NSCLC cell lines were treated with 5-Aza and IR. Cell viability, colony formation, wound healing, and transwell migration assays were performed to assess treatment effects. Microarray and qPCR analyses were conducted to identify gene expression changes. Additionally, subcutaneous and orthotopic xenograft models were used to evaluate the treatment's efficacy in vivo. Treatment with 5-Aza and IR resulted in significant reductions in cell viability, colony formation, and migration in NSCLC cell lines. Microarray analysis revealed significant changes in gene expression, including the upregulation of apoptosis-related genes and the downregulation of cell proliferation-related genes. In vivo studies demonstrated a notable reduction in tumor growth and metastasis in both subcutaneous and orthotopic NSCLC models following 5-Aza and IR treatment. Histological and bioluminescent imaging confirmed the therapeutic effects of the combined treatment. The combination of 5-Aza and IR shows promise as an effective treatment for NSCLC, enhancing apoptosis and reducing tumor growth through epigenetic modulation.

Testosterone-Induced H3K27 Deacetylation Participates in Granulosa Cell Proliferation Suppression and Pathogenesis of Polycystic Ovary Syndrome

Polycystic Ovary Syndrome (PCOS) is the leading cause of infertility in reproductive-age women. Hyperandrogenism, polycystic ovaries and chronic anovulation are its typical clinical features. However, the correlation between hyperandrogenism and ovarian follicle growth aberrations remains undisclosed. To advance our understanding of the molecular alterations in ovarian granulosa cells (GCs) with excessive androgen, epigenetic changes and affected gene expression in human granulosa-lutein cells (hGCs) and immortalized human GCs (KGN) were evaluated. A PCOS mouse model induced by dihydrotestosterone (DHT) was also established. This study found excessive testosterone significantly decreased the acetylation of lysine 27 on Histone H3 (H3K27ac). H3K27ac chromatin immunoprecipitation sequencing (ChIP-seq) data showed down-regulated expression of cell cycle-related genes (CCND1/CCND3/PCNA), which was confirmed by real-time quantitative PCR and western blot. Testosterone application impeding cell proliferation was also proved by Ki-67 immunofluorescence and flow-cytometric analysis. Moreover, testosterone influenced CK2α nuclear translocation, which increased the phosphorylation level of histone deacetylase 2 (HDAC2). Inhibition of CK2α nuclear translocation or silenced HDAC2 expression efficiently retarded H3K27 acetylation. Meanwhile, PCOS mouse model experiments also demonstrated decreased H3K27ac and enhanced HDAC2 phosphorylation in GCs. Cell proliferation-related genes were also downregulated in PCOS mouse GCs. In conclusion, hyperandrogenism in human and mouse GCs caused H3K27Ac aberrations, which are associated with CK2α nuclear translocation and HDAC2 phosphorylation, participating in abnormal follicle development in PCOS patients.

Functional study of the ST6GAL2 gene regulating skeletal muscle growth and development

ST6GAL2, a member of the sialoglycosyltransferase family, primarily localizes within the cellular Golgi apparatus. However, the role of the ST6GAL2 gene in skeletal muscle growth and development remains elusive. In this study, the impact of the ST6GAL2 gene on the proliferation, differentiation, and apoptosis of primary chicken myoblasts at the cellular level was investigated. Quantitative fluorescent PCR was used to measure the expression levels of genes. Subsequently, using gene knockout mice, we assessed its effects on skeletal muscle growth and development in vivo. Our findings reveal that the ST6GAL2 gene promotes the expression of cell cycle and proliferation-related genes, including CCNB2 and PCNA, and apoptosis-related genes, such as Fas and Caspase-9. At the individual level, double knockout of ST6GAL2 inhibited the formation of both fast and slow muscle fibers in the quadriceps, extensor digitorum longus, and tibial anterior muscle, while promoting their formation in the gastrocnemius and soleus. These results collectively demonstrate that the ST6GAL2 gene facilitates the proliferation, apoptosis, and fusion processes of primary chicken myoblasts. Additionally, it promotes the enlargement of cross-sectional muscle fiber areas and regulates the formation of fast and slow muscle fibers at the individual level, albeit inhibiting muscle fusion. This study provides valuable insights into the role of the ST6GAL2 gene in promoting proliferation of skeletal muscle.

Dynamic upregulation of retinoic acid signal in the early postnatal murine heart promotes cardiomyocyte cell cycle exit and maturation

The adult mammalian heart has extremely limited cardiac regenerative capacity. Most cardiomyocytes live in a state of permanent cell-cycle arrest and are unable to re-enter the cycle. Cardiomyocytes switch from cell proliferation to a maturation state during neonatal development. Although several signaling pathways are involved in this transition, the molecular mechanisms by which these inputs coordinately regulate cardiomyocyte maturation are not fully understood. Retinoic acid (RA) plays a pivotal role in development, morphogenesis, and regeneration. Despite the importance of RA signaling in embryo heart development, little is known about its function in the early postnatal period. We found that mRNA expression of aldehyde dehydrogenase 1 family member A2 (Aldh1a2), which encodes the key enzyme for synthesizing all-trans retinoic acid (ATRA) and is an important regulator for RA signaling, was transiently upregulated in neonatal mouse ventricles. Single-cell transcriptome analysis and immunohistochemistry revealed that Aldh1a2 expression was enriched in cardiac fibroblasts during the early postnatal period. Administration of ATRA inhibited cardiomyocyte proliferation in cultured neonatal rat cardiomyocytes and human cardiomyocytes. RNA-seq analysis indicated that cell proliferation-related genes were downregulated in prenatal rat ventricular cardiomyocytes treated with ATRA, while cardiomyocyte maturation-related genes were upregulated. These findings suggest that RA signaling derived from cardiac fibroblasts is one of the key regulators of cardiomyocyte proliferation and maturation during neonatal heart development.

RAD51 High-Expressed Hepatocellular Carcinomas Are Associated With High Cell Proliferation

IntroductionRAD51 is a pivotal DNA repair gene managing double-stranded DNA break recognition and repair. RAD51 high expression was associated with adverse outcomes in other cancer types. This study aims to investigate the tumor microenvironment and immune landscape in the RAD51 high-expressed Hepatocellular Carcinoma (HCCs). MethodsA total of 467 patients from two large independent cohorts with clinical and transcriptomic data were obtained. The cohort was dichotomized based on the median RAD51 gene expression. xCell and Gene Set Enrichment Analysis (GSEA) were used. ResultsRAD51 high-expressed HCCs were associated with worse recurrence-free, progression-free, disease-specific, and overall survival (all P < 0.05). While RAD51 high-expressed HCCs were associated with intratumoral heterogeneity, homologous recombination deficiency, and fraction altered scores, mutation or neoantigens were not increased in this group. xCell analysis demonstrated inconsistent immune cell infiltration between two cohorts. Cytolytic activity as well as GSEA with immune-related gene sets also demonstrated inconsistent results between two cohorts as well. On the other hand, RAD51 expression was significantly increased in higher-grade tumors, larger tumors, and higher clinical stages. RAD51 high-expressed HCCs were found to have elevated proliferation score. Furthermore, GSEA exhibited significant enrichment of all the cell proliferation–related gene sets in the Hallmark collection, including E2F targets, G2M checkpoint, Mitotic spindle, MYC targets, and MTORC1 signaling consistently in both cohorts (all false discovery rate < 0.25). ConclusionsRAD51 high-expressed HCCs were associated with worse survival and with increased cell proliferation and were not necessarily associated with immune infiltration or inflammation.

IGFBP7 promotes endothelial cell repair in the recovery phase of acute lung injury.

IGFBP7 has been found to play an important role in inflammatory diseases, such as acute lung injury (ALI). However, the role of IGFBP7 in different stages of inflammation remains unclear. Transcriptome sequencing was used to identify the regulatory genes of IGFBP7, and endothelial IGFBP7 expression was knocked down using Aplnr-Dre mice to evaluate the endothelial proliferation capacity. The expression of proliferation-related genes was detected by Western blotting and RT-PCR assays. In the present study, we found that knockdown of IGFBP7 in endothelial cells significantly decreases the expression of endothelial cell proliferation-related genes and cell number in the recovery phase but not in the acute phase of ALI. Mechanistically, using bulk-RNA sequencing and CO-IP, we found that IGFBP7 promotes phosphorylation of FOS and subsequently up-regulates YAP1 molecules, thereby promoting endothelial cell proliferation. This study indicated that IGFBP7 has diverse roles in different stages of ALI, which extends the understanding of IGFBP7 in different stages of ALI and suggests that IGFBP7 as a potential therapeutic target in ALI needs to take into account the period specificity of ALI.

T cell proliferation-related subtypes, prognosis model and characterization of tumor microenvironment in head and neck squamous cell carcinoma

BackgroundThirty-three synthetic driver genes of T-cell proliferation have recently been identified through genome-scale screening. However, the tumor microenvironment (TME) cell infiltration, prognosis, and response to immunotherapy mediated by multiple T cell proliferation-related genes (TRGs) in patients with head and neck squamous cell carcinoma (HNSC) remain unclear. MethodsThis study examined the genetic and transcriptional changes in 771 patients with HNSC by analyzing the TRGs from two independent datasets. Two different subtypes were analyzed to investigate their relationship with immune infiltrating cells in the TME and patient prognosis. The study also developed and validated a risk score to predict overall survival (OS). Furthermore, to enhance the clinical utility of the risk score, an accurate nomogram was constructed by combining the characteristics of this study. ResultsThe low-risk score observed in this study was associated with high levels of immune checkpoint expression and TME immune activation, indicating a favorable OS outcome. Additionally, various factors related to risk scores were depicted. ConclusionThrough comprehensive analysis of TRGs in HNSC, our study has revealed the characteristics of the TME and prognosis, providing a basis for further investigation into TRGs and the development of more effective immunotherapy and targeted therapy strategies.

Potential involvement of KANK1 haploinsufficiency in centrosome aberrations

KANK1 was found as a tumor suppressor gene based on frequent deletions in renal cell carcinoma and the inhibitory activity of tumor cell proliferation. Previously, we reported that knockdown of KANK1 induced centrosomal amplification, leading to abnormal cell division, through the hyperactivation of RhoA small GTPase. Here, we investigated the loss of KANK1 function by performing CRISPR/Cas9-based genome editing to knockout the gene. After several rounds of genome editing, however, there were no cell lines with complete loss of KANK1, and the less the wild-type KANK1 dosage, the greater the number of cells with abnormal numbers of centrosomes and rates of cell-doubling and apoptosis, suggesting the involvement of KANK1 haploinsufficiency in centrosome aberrations. The rescue of KANK1-knockdown cells with a KANK1-expressing plasmid restored the rates of cells exhibiting centrosomal amplification to the control level. RNA-sequencing analysis of the cells with reduced dosages of functional KANK1 revealed potential involvement of other cell proliferation-related genes, such as EGR1, MDGA2, and BMP3, which have been reported to show haploinsufficiency when they function. When EGR1 protein expression was reduced by siRNA technology, the number of cells exhibiting centrosomal amplification increased, along with the reduction of KANK1 protein expression, suggesting their functional relationship. Thus, KANK1 haploinsufficiency may contribute to centrosome aberrations through the network of haploinsufficiency-related genes.

Discovery of a T cell proliferation-associated regulator signature correlates with prognosis risk and immunotherapy response in bladder cancer.

The efficacy of immunotherapy is heavily influenced by T cell activity. This study aimed to examine how T cell proliferation regulators can predict the prognosis and response to immunotherapy in patients with bladder cancer (BCa). T cell proliferation-related subtypes were determined by employing the non-negative matrix factorization (NMF) algorithm that analyzed the expression patterns of T cell proliferation regulators. Subtypes were assessed for variations in prognosis, immune infiltration, and functional behaviors. Subsequently, a risk model related to T cell proliferation was created through Cox and Lasso regression analyses in the TCGA cohort and then confirmed in two GEO cohorts and an immunotherapy cohort. BCa patients were categorized into two subtypes (C1 and C2) according to the expression profiles of 31T cell proliferation-related genes (TRGs) with distinct prognoses and immune landscapes. The C2 subtype had a shorter overall survival (OS), with higher levels of M2 macrophage infiltration, and the activation of cancer-related pathways than the C1 subtype. Following this, thirteen prognosis-related genes that were involved in T cell proliferation were utilized to create the prognostic signature. The model's predictive accuracy was confirmed by analyzing both internal and external datasets. Individuals in the high-risk category experienced a poorer prognosis, increased immunosuppressive factors in the tumor microenvironment, and diminished responses to immunotherapy. Additionally, the immunotherapeutic prediction efficacy of the model was further confirmed by an immunotherapy cohort (anti-PD-L1 in the IMvigor210 cohort). Our study characterized two subtypes linked to T cell proliferation in BCa patients with distinct prognoses and tumor microenvironment (TME) patterns, providing new insights into the heterogeneity of T cell proliferation in BCa and its connection to the immune landscape. The signature has prospective clinical implications for predicting outcomes and may help physicians to select prospective responders who prioritize current immunotherapy.

Cytoplasmic tail of transmembrane dscam controls antibacterial responses by regulating cell proliferation-related genes in hemocytes of Chinese mitten crab (Eriocheir sinensis)

In arthropods, the involvement of Dscam (Down syndrome cell adhesion molecule) in innate immunity has been extensively demonstrated. Its cytoplasmic tail contains multiple conserved functional sites, which indicates its involvement in different intracellular signaling pathways. In this study, we focused on the role of the cytoplasmic tail of Dscam in the Chinese mitten crab (Eriocheir sinensis) immune defense. In the group with cytoplasmic tail knockdown (the site was located on constant exons 37 and 38), 3885 differentially expressed genes (DEGs) were identified. The DEGs were enriched in small molecule binding, protein-containing complex binding, and immunity-related pathways. The expression of selected genes were validated using quantitative real-time reverse transcription PCR. We identified key Cell cycle, Janus kinase (JAK)-signal transducer, activator of transcription (STAT) and mitogen-activated protein kinase (MAPK) signaling pathway genes, the results indicated that the cytoplasmic tail of Dscam controls antibacterial responses by regulating cell proliferation-related genes in hemocytes.

Proteogenomic characterization of difficult-to-treat breast cancer with tumor cells enriched through laser microdissection

BackgroundBreast cancer (BC) is the most commonly diagnosed cancer and the leading cause of cancer death among women globally. Despite advances, there is considerable variation in clinical outcomes for patients with non-luminal A tumors, classified as difficult-to-treat breast cancers (DTBC). This study aims to delineate the proteogenomic landscape of DTBC tumors compared to luminal A (LumA) tumors.MethodsWe retrospectively collected a total of 117 untreated primary breast tumor specimens, focusing on DTBC subtypes. Breast tumors were processed by laser microdissection (LMD) to enrich tumor cells. DNA, RNA, and protein were simultaneously extracted from each tumor preparation, followed by whole genome sequencing, paired-end RNA sequencing, global proteomics and phosphoproteomics. Differential feature analysis, pathway analysis and survival analysis were performed to better understand DTBC and investigate biomarkers.ResultsWe observed distinct variations in gene mutations, structural variations, and chromosomal alterations between DTBC and LumA breast tumors. DTBC tumors predominantly had more mutations in TP53, PLXNB3, Zinc finger genes, and fewer mutations in SDC2, CDH1, PIK3CA, SVIL, and PTEN. Notably, Cytoband 1q21, which contains numerous cell proliferation-related genes, was significantly amplified in the DTBC tumors. LMD successfully minimized stromal components and increased RNA–protein concordance, as evidenced by stromal score comparisons and proteomic analysis. Distinct DTBC and LumA-enriched clusters were observed by proteomic and phosphoproteomic clustering analysis, some with survival differences. Phosphoproteomics identified two distinct phosphoproteomic profiles for high relapse-risk and low relapse-risk basal-like tumors, involving several genes known to be associated with breast cancer oncogenesis and progression, including KIAA1522, DCK, FOXO3, MYO9B, ARID1A, EPRS, ZC3HAV1, and RBM14. Lastly, an integrated pathway analysis of multi-omics data highlighted a robust enrichment of proliferation pathways in DTBC tumors.ConclusionsThis study provides an integrated proteogenomic characterization of DTBC vs LumA with tumor cells enriched through laser microdissection. We identified many common features of DTBC tumors and the phosphopeptides that could serve as potential biomarkers for high/low relapse-risk basal-like BC and possibly guide treatment selections.

Abstract PO5-14-09: Does transcriptome based DEPTH2 score reflect intratumor heterogeneity in breast cancer patients?

Abstract Background: Intratumor heterogeneity (ITH) refers to the presence of distinct cancer cell populations with different clones within a single tumor mass. Tumors with high ITH are more prone to progression, exhibit resistance to therapies, and are associated with an unfavorable prognosis. Therefore, evaluation of ITH is anticipated to serve as a breakthrough biomarker for prognosis and treatment strategies. Several computational algorithms have been proposed to quantify ITH. However, with the exception of DEPTH2, all of these algorithms require both DNA and RNA-sequence data from the same tumor, which can be challenging. In this study, we investigated whether DEPTH2 which solely analyzes RNA-sequence data, accurately reflects the biological characteristics of ITH. Methods: We analyzed clinicopathological and gene expression data from a total of 6573 breast cancer patients from several large independent cohorts: METABRIC (n = 1903), GSE96058 (n = 3273), GSE21974 (n = 57), GSE28844 (n = 61), GSE87455 (n = 153), GSE180280 (n = 57), and The Cancer Genome Atlas (TCGA, n = 1069). Results: DEPTH2 score was high in Triple Negative Breast Cancer (TNBC) subtype (p &amp;lt; 0.001), but no consistent correlation was observed with lymph node or distal metastasis. Higher DEPTH2 score was associated with cell proliferation, as evidenced by higher Nottingham histological grade and Ki67 gene expression (both p &amp;lt; 0.001). In agreement, high DEPTH2 tumors enriched all cell proliferation-related Hallmark gene sets such as E2F targets, G2M checkpoint, MYC targets v1 and v2, and Mitotic Spindle (FDR &amp;lt; 0.25). Additionally, high DEPTH2 tumors exhibited reduced immune cell infiltrations, such as CD8, CD4, Th1, Th2, B cells, and macrophages, and increased infiltrations of stromal cells, such as adipocytes, fibroblasts, blood and lymphatic endothelial cells (all p &amp;lt; 0.05). In TCGA cohort, DEPTH2 score exhibited a similar trend to intratumoral heterogeneity, homologous recombination deficiency, fraction altered, silent and nonsilent mutations, as well as SNV and Indel neoantigens. However, the Pearson’s correlation coefficient was very weak (p &amp;lt; 0.05). DEPTH2 score decreased in the GSE21974 and GSE87455 cohorts after neoadjuvant chemotherapy (NAC), whereas no change was observed in the GSE28844 and GSE180280 cohorts. DEPTH2 high tumors showed a lower rate of pathologic complete response (pCR) after NAC in estrogen receptor (ER)+HER2- subtype across all cohorts, however, opposite pattern was observed in the HER2+ and TNBC subtypes in all cohorts. Lastly, high DEPTH2 score was associated with lower disease free and overall survival in METABRIC and GSE96058 (p &amp;lt; 0.05), but not in the TCGA cohort. Conclusions: Our findings suggest that DEPTH2 score may not completely capture the biological characteristics associated with intratumor heterogeneity. Citation Format: Kohei Chida, Rongrong Wu, Arya Mariam Roy, Takashi Ishikawa, Kazuaki Takabe. Does transcriptome based DEPTH2 score reflect intratumor heterogeneity in breast cancer patients? [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-14-09.

Abstract PO3-13-12: ER-positive/HER2-negative breast cancer in Adolescent &amp; Young Adult (AYA) age group has a specific biological feature and worse outcome compared to other generations

Abstract Background: Adolescents &amp; Young Adults (AYA) is commonly defined as patients younger than 40 years old. Breast cancer patients in AYA has been reported to have poor outcome compared to other generation, however, the clinicopathological and biological features of AYA breast cancer remains controversial partly because many previous studies did not consider the difference in subtypes by age. We aim to clarify the features of AYA compared with the other age group in ER-positive/HER2-negative breast cancer, assuming the effects of age-related hormonal status. Material and Methods: Each analyzed cohort were divided into four age groups; AYA (15-39yo), perimenopausal (40-55yo), menopausal (55-65yo), and old (65+yo). Clinicopathological and biological features were analyzed using gene set variation analysis and the xCell algorithm using mRNA expression profiles of large independent public databases (METABRIC; n = 1,903, GSE96058; n = 3,273). Results: We found that both clinical and pathological T-category of AJCC staging were larger in AYA and Old compared from the other groups. Pathological N-category as well as pathological Stage were higher in AYA. Nottingham histological grade 3 was significantly higher in the AYA compared with the other older groups. Among the subtypes, AYA breast cancer was significantly associated with higher rate of triple-negative breast cancer compared to the others, as expected. Considering the whole cohort, ER and PgR positivity trended to be lower, but HER2-positivity trended to be higher in AYA. Within the ER-positive/HER2-negative subtype, PgR positivity was higher in the AYA and Perimenopausal groups compared to others. AYA had poorer disease-specific survival than other groups (p = 0.010 and p = 0.002, respectively), as well as overall survival, especially compared to perimenopausal group. The survival difference was more pronounced in ER-positive/HER2-negative breast cancer patients. In biological analysis in ER-positive/HER2-negative subtype, we found that estrogen response late signaling level decreased as the age group gets older. AYA breast cancer had significant enrichment in cell proliferation-related gene sets (G2M checkpoint, E2F targets, and MYC target v1), other pro-cancerous gene sets (MTORC1, unfolded protein response, and PI3K/ACT/MTOR signaling), consistently in two cohorts (all p ≦ 0.028), when compared to the other age groups. Interestingly, the features were observed even in the small tumor size (T1/T2) subgroup. Furthermore, AYA breast cancer showed significantly high BRCAness (all p≦0.002) and DNA repair (all p≦0.023) compared to other age groups. The infiltration fraction of several immune cells: CD8+ T cells, M1 macrophages, regulatory T cells, helper type 2 T cells, were significantly higher, and M2 macrophages were significantly lower in AYA, consistently in two cohorts. Conclusion: ER-positive/HER2-negative breast cancer in AYA was highly proliferative with high immune cell infiltrations compared to other generations. This may be related to the difference in outcomes in each age group. Considering these unique features may enable us to fine tune treatment strategies for AYA. Citation Format: Masanori Oshi, Akimitsu Yamada, Mahato Sasamoto, Kei Kawashima, Yoshie Fujiwara, Shoko Adachi, Shinya Yamamoto, Kazutaka Narui, Takashi Ishikawa, Itaru Endo, Kazuaki Takabe. ER-positive/HER2-negative breast cancer in Adolescent &amp; Young Adult (AYA) age group has a specific biological feature and worse outcome compared to other generations [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 PO3-13-12.

Abstract PO3-15-10: Enhanced Cancer Cell Proliferation and Aggressive Phenotype Counterbalance in Breast Cancer with High BRCA1 Gene Expression

Abstract Introduction: It is estimated that 5–10% of all breast cancer cases have a hereditary component with BRCA1 mutation being one of the most frequently observed gene mutations in breast cancer patients. BRCA1 plays a crucial role in DNA repair, and its mutation has been extensively studied. However, the clinical significance of BRCA1 gene expression remains largely unexplored. Given that heightened DNA repair mechanisms can potentially increase cancer cell proliferation, we hypothesized that breast cancer with high BRCA1 gene expression might be associated with aggressive tumor biology and worse survival. Methods: The clinical, pathological and gene expression levels of a total of 6,245 breast cancer patients were analyzed from three large independent cohorts: METABRIC (n = 1,903), GSE96058 (n = 3,273), and The Cancer Genome Atlas (TCGA, n = 1,069). The data was retrieved through cBioPortal. The xCell algorithm was used to correlate the BRCA1 gene expression with the stromal and immune cell fractions infiltrating the tumor microenvironment (TME). Results: BRCA1 gene expression was higher in breast cancer patients without BRCA1 mutation, and it correlated with the DNA repair activity (p = 0.026 and p &amp;lt; 0.01 respectively), however, it did not correlate with BRCA2 gene expression (p = 0.38). Breast cancer with high BRCA1 gene expression was associated with cancer cell proliferation as evidenced by higher Nottingham histological grade (p &amp;lt; 0.001), Ki67 expression (p &amp;lt; 0.001), significant enrichment of cell proliferation-related gene sets such as E2F Targets, G2M Checkpoint, MYC Targets V1 and V2, Mitotic Spindle (all FDR &amp;lt; 0.25), and significantly less infiltration of stromal cells such as adipocytes, fibroblasts, microvascular and lymphatic endothelial cells, and pericytes (all p &amp;lt; 0.05). High BRCA1 gene expression was associated with higher homologous recombination deficiency, intratumor genomic heterogeneity, and fraction altered (all p &amp;lt; 0.001); however, there was no correlation observed with mutation rates or neoantigens. It was observed that breast cancer with high BRCA1 gene expression had less infiltration of CD8 T cells, dendritic cells, regulatory T cells, and B cells and had higher infiltration of Th1 cells (all p &amp;lt; 0.05). To our surprise, there was no significant difference in overall survival regardless of the subtypes (except for ER+/HER2- subtype in METABRIC cohort, p = 0.03). Breast cancer with low BRCA1 gene expression enriched cancer aggravating pathway gene sets such as Cancer Stem Cell-related signaling pathways (NOTCH and HEDGEHOG), Angiogenesis, Epithelial Mesenchymal Transition, Inflammatory Response, and TGF-beta signaling (all FDR &amp;lt; 0.25). Conclusion: Contrary to our initial hypothesis, we did not find any significant association between BRCA1 gene expression and survival outcomes in breast cancer patients. Based on the results of our study, we speculate that the interplay between enhanced cancer cell proliferation and aggressive tumor characteristics may counterbalance the effect of high BRCA1 expression in breast cancer. Citation Format: Kohei Chida, Masanori Oshi, Arya Mariam Roy, Itaru Endo, Kazuaki Takabe. Enhanced Cancer Cell Proliferation and Aggressive Phenotype Counterbalance in Breast Cancer with High BRCA1 Gene Expression [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 PO3-15-10.

Abstract PO3-25-03: Can intratumoral microRNA-125a levels be a prognostic biomarker of a ER-positive breast cancer patients？

Abstract Background: MicroRNA-125a (miR-125a) has been shown to function as tumor suppressive miRNA by pre-clinical in vitro studies. However, to the best of our knowledge, there has been no study that investigated the clinical relevance of miR-125a in breast cancer patients. We hypothesized that miR-125a expression in breast cancer associate with its aggressiveness and can be a prognostic biomarker. Material and Methods: Non-tumorigenic epithelial cell line, MCF-10A and breast cancer cell lines, MCF-7, T47D, and MDA-MB231, were used to analyze the expression levels of miR-125a as well as cell viability. The data of 2042 patients were extracted from publicly available databases, The Molecular Taxonomy of Breast Cancer International Consortium (METARBRIC), The Cancer Genome Atlas (TCGA), and GSE57897. These databases included clinicopathological and survival data as well as transcriptome data. The survival analysis, gene set enrichment analysis (GSEA) were conducted comparing miR-125a high expressing and low expressing tumors, divided by the median cutoff. The association between the miR-125a expression and tumor immune microenvironment was assessed by xCell. Results: The expression levels of miR-125a were suppressed in breast cancer cell lines, MCF-7, T47D, and MDA-MB231compared with MCF-10A. This was concordant with human samples. The expression levels of miR-125a were lower in tumors compared with normal breast tissues in both TCGA and GSE57897 cohorts. These results were in agreement with the notion that it is a tumor suppressive miRNA (p&amp;lt; 0.001 and p&amp;lt; 0.001, respectively). ER-positive/HER2-negative (ER+/HER2-) showed the highest miR-125a expression among the subtypes in TCGA (p&amp;lt; 0.001). MiR-125a expression was not associated with cancer staging in any of the subtypes in neither TCGA nor METABRIC cohorts. To our surprise, high miR-125a tumors demonstrated worse disease free survival (DFS), disease specific survival (DSS), and overall survival (OS) compared with low expressing in ER+/HER2- breast cancer patients (p=0.008, p=0.005, and p=0.037) which was not the case for the other subtypes in METABRIC cohort. Interestingly, miR-125a expression was associated with Nottingham histological grade only in ER+/HER2- among the subtypes (p&amp;lt; 0.001). Also, high miR-125a tumors significantly demonstrated higher expression of MKI67, one of the most commonly used parameters for cell proliferation, correlated with miR-125a expression in ER+/HER2- (p=0.02), but not in other subtypes. Furthermore, high miR-125a tumors enriched four out of five cell proliferation-related gene sets in Hallmark collection, such as E2F Targets, G2M Checkpoint, Mitotic Spindle, and MYC Targets V2 in ER+/HER2- subtype, but not in TNBC. This was also the case in immune-related gene sets; interferon-alpha response and interferon-gamma response that enriched to high miR-125a tumors in ER+/HER2-, but not in TNBC. Anti-tumor immune cells, CD8 cells, T-helper type 1 cells, and M1 macrophages, were all elevated in high miR-125a tumors in ER+/HER2- subtype (all p&amp;lt; 0.03), but none in TNBC. Also, pro-cancerous immune cell such as T-helper type 2 cells were similarly highly infiltrated with high miR-125a tumors only in ER+/HER2- subtype (p=0.026). Given its association with the survival outcome, we cannot help but speculate that miR-125a expression is parallel with highly proliferative ER+/HER2- breast cancer, but its tumor suppressive effect is not enough to improve survival outcome. Conclusion: High miR-125a levels in tumors were associated with aggressive biology and worse survival, thus it can be a candidate for a prognostic biomarker in ER+/HER2- patients. Citation Format: Yoshihisa Tokumaru, Masanori Oshi, Mai Okawa, Saki Ando, Yoshimi Niwa, Ryutaro Mori, Kazuaki Takabe, Manabu Futamura. Can intratumoral microRNA-125a levels be a prognostic biomarker of a ER-positive breast cancer patients？ [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 PO3-25-03.