Deteriorated bone microarchitecture caused by sympathetic overstimulation in pheochromocytoma and paraganglioma

PURPOSE

Despite the potentially destructive effect of sympathetic activity on bone metabolism, its impact on bone microarchitecture, a key determinant of bone quality, has not been thoroughly investigated. This study aims to evaluate the impact of sympathetic activity on bone microarchitecture and bone strength in patients with pheochromocytoma and paraganglioma (PPGL).

METHODS

A cross-sectional study was conducted in 38 PPGL patients (15 males and 23 females). Bone turnover markers serum procollagen type 1 N-terminal propeptide (P1NP) and β-carboxy-terminal crosslinked telopeptide of type 1 collagen (β-CTX) were measured. 24-h urinary adrenaline (24hUE) and 24-h urinary norepinephrine levels (24hUNE) were measured to indicate sympathetic activity. High-resolution peripheral quantitative computed tomography (HR-pQCT) was conducted to evaluate bone microarchitecture in PPGL patients and 76 age-, sex-matched healthy controls (30 males and 46 females). Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry (DXA) simultaneously.

RESULTS

PPGL patients had a higher level of β-CTX. HR-pQCT assessment revealed that PPGL patients had notably thinner and more sparse trabecular bone (decreased trabecular number and thickness with increased trabecular separation), significantly decreased volume BMD (vBMD), and bone strength at both the radius and tibia compared with healthy controls. The deterioration of Tt.vBMD, Tb.Sp, and Tb.1/N.SD was more pronounced in postmenopausal patients compared with the premenopausal subjects. Moreover, subjects in the highest 24hUNE quartile (Q4) showed markedly lower Tb.N and higher Tb.Sp and Tb.1/N.SD at the tibia than those in the lowest quartile (Q1). Age-related bone loss was also exacerbated in PPGL patients to a certain extent.

CONCLUSIONS

PPGL patients had significantly deteriorated bone microarchitecture and strength, especially in the trabecular bone, with an increased bone resorption rate. Our findings provide clinical evidence that sympathetic overstimulation may serve as a secondary cause of osteoporosis, especially in subjects with increased sympathetic activity.

CRTAM promotes antitumor immune response in triple negative breast cancer by enhancing CD8+ T cell infiltration

The immunomodulatory (IM) subtype of triple negative breast cancer (TNBC) exhibits high expression of immune cell signaling genes and is more responsive to immunotherapy. However, the specific mechanism underlying this phenomenon remains unclear. One of the potential key genes appears to be the cytotoxic and regulatory T cell molecule (CRTAM). A cohort of 360 previously untreated TNBC patients from Fudan University Shanghai Cancer Center (FUSCC) underwent RNA sequencing analysis of their primary tumor tissue. Combined with three RNA-seq datasets obtained from the GEO database, a LASSO regression analysis was conducted to identify genes specific to the IM type of TNBC. Our findings revealed elevated CRTAM expression in the IM-type TNBC, which correlated with a favorable overall survival and recurrence-free survival in TNBC patients. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated a strong association between CRTAM and immune responses as well as immune system processes. Notably, CRTAM overexpression induced STAT1 phosphorylation and upregulation of interferon-stimulated genes. We also found that CRTAM enhanced tumor-associated immune cell infiltration, especially CD8+ T cells, which may be related to the increased expression of MHC class I molecules caused by CRTAM overexpression. These results suggest that CRTAM may serve as a potential biomarker for predicting the efficacy of immunotherapy in TNBC.

MNX1 Promotes Anti-HER2 Therapy Sensitivity via Transcriptional Regulation of CD-M6PR in HER2-Positive Breast Cancer

Although targeted therapy for human epidermal growth factor receptor 2 (HER2)-positive breast cancer has significantly prolonged survival time and improved patients' quality of life, drug resistance has gradually emerged. This study explored the mechanisms underlying the effect of the motor neuron and pancreatic homeobox 1 (MNX1) genes on drug sensitivity in HER2-positive breast cancer. From July 2017 to 2018, core needle biopsies of HER2-positive breast cancer were collected from patients who received paclitaxel, carboplatin, and trastuzumab neoadjuvant therapy at our center. Based on treatment efficacy, 81 patients were divided into pathological complete response (pCR) and non-pCR groups. High-throughput RNA sequencing results were analyzed along with the GSE181574 dataset. MNX1 was significantly upregulated in the pCR group compared with the non-pCR group in both sequencing datasets, suggesting that MNX1 might be correlated with drug sensitivity in HER2-positive breast cancer. Meanwhile, tissue array results revealed that high MNX1 expression corresponded to a good prognosis. In vitro functional tests showed that upregulation of MNX1 significantly increased the sensitivity of HER2-positive breast cancer cells to lapatinib and pyrotinib. In conclusion, MNX1 may serve as a prognostic marker for patients with HER2-positive breast cancer, and its expression may facilitate clinical screening of patients sensitive to anti-HER2-targeted therapy.

[Establishment of a digital remote platform for respiratory support and intelligent early warning in intensive care units]

During the disease progression or treatment of critically ill patients with lung injury, the changes in respiratory mechanics are continuous and dynamic. Establishing a digital platform for respiratory support in the ICU, which enables the continuous recording, dynamic analysis, and real-time alerting of numerical and waveform data from mechanical ventilation, can help intensivists improve their understanding of "dynamic respiratory mechanics", improve respiratory therapy and patient outcomes, as well as reduce workload and increase work efficiency. The construction of a dedicated database for mechanical ventilation, based on ventilator waveforms provides essential data support for projects such as respiratory mechanics data algorithm models. This will facilitate the establishment of an auxiliary decision-making system, enable the realization of intelligent mechanical ventilation, and create a new era of dynamic respiratory mechanics.

R-loop-dependent promoter-proximal termination ensures genome stability

The proper regulation of transcription is essential for maintaining genome integrity and executing other downstream cellular functions1,2. Here we identify a stable association between the genome-stability regulator sensor of single-stranded DNA (SOSS)3 and the transcription regulator Integrator-PP2A (INTAC)4-6. Through SSB1-mediated recognition of single-stranded DNA, SOSS-INTAC stimulates promoter-proximal termination of transcription and attenuates R-loops associated with paused RNA polymerase II to prevent R-loop-induced genome instability. SOSS-INTAC-dependent attenuation of R-loops is enhanced by the ability of SSB1 to form liquid-like condensates. Deletion of NABP2 (encoding SSB1) or introduction of cancer-associated mutations into its intrinsically disordered region leads to a pervasive accumulation of R-loops, highlighting a genome surveillance function of SOSS-INTAC that enables timely termination of transcription at promoters to constrain R-loop accumulation and ensure genome stability.

[A case report of autosomal recessive bestrophinopathy]

The patient is a 40-year-old male who presented to the ophthalmology clinic due to easy visual fatigue for the past 3 months. Two months ago, the patient was misdiagnosed with "bilateral posterior uveitis", but the diagnosis was ruled out after ineffective treatment with corticosteroids. During the current visit, fundus examination revealed yellow-white material exudation below the macular center in both eyes. Considering the results of the ophthalmic examination and the genetic testing of the patient and his son, the patient was diagnosed with autosomal recessive bestrophinopathy.

[The 501st case: elevated blood glucose, chronic pancreatitis, and post- pancreatoduodenectomy malnutrition]

A 50-year-old man with a 15-year history of elevated blood glucose and an approximately 2-year history of diarrhea was admitted to the Peking Union Medical College Hospital. The initial diagnosis was type 2 diabetes. After repeated pancreatitis and pancreatoduodenectomy, severe pancreatic endocrine and exocrine dysfunction including alternating high and low blood glucose and fat diarrhea occurred. Tests for type 1 diabetes-related antibodies were all negative, C-peptide levels were substantially reduced, fat-soluble vitamin levels were reduced, and there was no obvious insulin resistance. Therefore, a diagnosis of pancreatic diabetes was clear. The patient was given small doses of insulin and supplementary pancreatin and micronutrients. Diarrhea was relieved and blood glucose was controlled. The purpose of this article is to raise clinicians' awareness of the possibility of pancreatic diabetes after pancreatitis or pancreatic surgery. Timely intervention and monitoring may reduce the occurrence of complications.

Abstract P3-05-46: scRNA-seq profiling reveals different tumor immune-microenvironment in triple negative breast cancer and decodes pivotal role of THBS1- SDC1 axis in tumor metastasis

ABSTRACT Background: Breast cancer has become the most common cancer worldwide and triple-negative breast cancer (TNBC) is the most aggressive subtype due to the lacks of hormone receptors and HER2 expression. Increasing rate of breast cancer metastasis also need to be solved. Nearly one in four breast cancer patients developed metastasis after treatment, which attributed to 90% cancer related death. Considering highly aggressive pattern of TNBC, TNBC showed higher metastasis probability rather than other subtypes. Therefore, exploring more biomarkers and therapeutic targets are on urgent. Methods: We profiled the transcriptomes of 59646 cells from 12 primary and 4 metastatic tumor samples from Gene Expression Omnibus (GEO) database (https://www.ncbi.nlm.nih.gov/geo/). Results: Comparing with primary site, metastatic site was predominated with immunosuppressive tumor microenvironment. In brief, metastatic samples showed increasing numbers of macrophages, lower anti-tumor microenvironment scores, higher malignant cell properties scores, less effective T cells and macrophages, enhanced immune escape potential tumor cells and a later pseudotime state of malignant cells, compared with primary samples. Remarkably, metastatic samples exhibited a stronger interaction of THBS1-SDC1 axis between macrophage subcluster named angiogenesis-1 and malignant cell subcluster named CDKN2A epithelial cells. We subsequently confirmed that higher THBS1-SDC1 expression indicated with poor overall survival and distant metastatic free survival of TNBC patients in The Cancer Genome Atlas (TCGA) TNBC cohort. Conclusion: Our immune landscape of TNBC ecosystem provide deeper insights into tumor metastasis and offer potential biomarkers and therapeutic target for TNBC. Key words: Breast cancer; immune-microenvironment; THBS1; SDC1; metastasis

Citation Format: Liyi Zhang, Qi Zhang, Pei Li, Min Xiong, Yue Zhou, Jingyan Xue, Ming Chen, Wei-Ru Chi, Hengyu Ren, Chih Wan Goh, Douwaner Liu, Liren Wangxu, Yayun Chi, Bingqiu Xiu, Jiong Wu. scRNA-seq profiling reveals different tumor immune-microenvironment in triple negative breast cancer and decodes pivotal role of THBS1- SDC1 axis in tumor metastasis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-46.

Abstract P1-13-15: Elevated TCEAL9 Expression Is Correlated With Trastuzumab-based Neoadjuvant Chemotherapy Resistance In HER2-positive Breast Cancer

Background: -Trastuzumab-based neoadjuvant chemotherapy has shown to have remarkable clinical benefits for HER2-positive breast cancer patients who had higher tumor burden. -Patients who achieved pathological complete response (pCR) are known to have better prognosis. -However, certain patients have little response or are not sensitive to trastuzumab-based treatment regimens. -Understanding the mechanism of trastuzumab resistance is crucial for the development of new therapeutic strategy. Objectives: To investigate the role of TCEAL9 in developing trastuzumab resistance in HER2-positive breast cancer Methods: A total of 83 patients who received paclitaxel, carboplatin and trastuzumab neoadjuvant chemotherapy in Fudan University Shanghai Cancer Center(FUSCC) from 2016 to 2018 were enrolled in this study. After completed neoadjuvant chemotherapy and surgery, gene expressions were compared between the pCR and non-pCR groups. Total RNA from formalin-fixed paraffin-embedded tissue sections was isolated and RNA-sequencing was performed. Gene sets from GEO dataset GSE52707 were used to analyze TCEAL9 expression in resistant and non-resistant cell lines. Gene expression levels were converted into log2 values and row-wised standardized. BT-474 and SK-BR-3 cell lines were transduced with each expression lentivirus, followed by selection with puromycin for stable expression. TCEAL9 mRNA and protein level evaluation was evaluated by qPCR and western blot. The influence of TCEAL9 expression on proliferation and sensitivity to HER2-targeted therapy was evaluated by CCK8. BT-474 and SK-BR-3 transfected cells were plated in 96-well plates with 4,000 cells per well. After 3 or 5 days of incubation with trastuzumab, pertuzumab or lapatinib, the viability of cells was measured using Cell Proliferation Assay. Comparisons between Kaplan-Meier curves were performed using the long-rank test. Results: TCEAL9 was elevated significantly (P< 0.05) in non-pCR patients in the FUSCC cohort and was associated with lapatinib resistance in GSE52707 from GEO datasets. Patients with elevated TCEAL9 expression had worse recurrence-free survival (RFS), distant metastasis-free survival (DMFS) and progression-free survival (PPS) (all P< 0.05)by using KM-plotter. Overexpression of TCEAL9 was associated with lapatinib(IC50= 5.56 vs 10.90nM) and trastuzumab + pertuzumab(IC50= 745 vs 635nM) resistance in BT-474 and SK-BR-3 respectively, but has no influence in proliferation. In this study, we found that TCEAL9 could induce HER2-positive breast cancer cells resistance to HER2-targeted therapy through the activation of mTOR signaling pathway. After EGFR stimulation, TCEAL9 has a higher mTOR phosphorylation level in BT-474 cells. TCEAL9 elevation also increased HER2 and mTOR phosphorylation after lapatinib treatment in SK-BR-3 cells. In addition, the elevation of TCEAL9 has a positive correlation with HER2 signaling pathways such as EGFR, PIK3R1, FOXO1 and AKT3 in TCGA datasets. Conclusions: TCEAL9 expression correlates with trastuzumab resistance and high TCEAL9 expression is associated with poor prognosis in HER2-positive breast cancer patients.

Citation Format: Chih Wan Goh, Wei-Ru Chi, Liyi Zhang, Qi Zhang, Ming Chen, Min Xiong, Douwaner Liu, Hengyu Ren, Bingqiu Xiu, Jingyan Xue, Yayun Chi, Jiong Wu. Elevated TCEAL9 Expression Is Correlated With Trastuzumab-based Neoadjuvant Chemotherapy Resistance In HER2-positive Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-13-15.

High prevalence of vertebral deformity in tumor-induced osteomalacia associated with impaired bone microstructure

PURPOSE

Patients with tumor-induced osteomalacia (TIO) often suffer from irreversible height loss due to vertebral deformity. However, the prevalence of vertebral deformity in TIO patients varies among limited studies. In addition, the distribution and type of vertebral deformity, as well as its risk factors, remain unknown. This study aimed to identify the prevalence, distribution, type and risk factors for vertebral deformity in a large cohort of TIO patients.

METHODS

A total of 164 TIO patients were enrolled in this retrospective study. Deformity in vertebrae T4-L4 by lateral thoracolumbar spine radiographs was evaluated according to the semiquantitative method of Genant. Bone microstructure was evaluated by trabecular bone score (TBS) and high-resolution peripheral QCT (HR-pQCT).

RESULTS

Ninety-nine (99/164, 60.4%) patients had 517 deformed vertebrae with a bimodal pattern of distribution (T7-9 and T11-L1), and biconcave deformity was the most common type (267/517, 51.6%). Compared with patients without vertebral deformity, those with vertebral deformity had a higher male/female ratio, longer disease duration, more height loss, lower serum phosphate, higher bone turnover markers, lower TBS, lower areal bone mineral density (aBMD), lower peripheral volumetric BMD (vBMD) and worse microstructure. Lower trabecular vBMD and worse trabecular microstructure in the peripheral bone and lower spine TBS were associated with an increased risk of vertebral deformity independently of aBMD. After adjusting for the number of deformed vertebrae, we found little difference in clinical indexes among the patients with different types of vertebral deformity. However, we found significant correlations of clinical indexes with the number of deformed vertebrae and the spinal deformity index.

CONCLUSION

We reported a high prevalence of vertebral deformity in the largest cohort of TIO patients and described the vertebral deformity in detail for the first time. Risk factors for vertebral deformity included male sex, long disease duration, height loss, abnormal biochemical indexes and bone impairment. Clinical manifestation, biochemical indexes and bone impairment were correlated with the number of deformed vertebrae and degree of deformity, but not the type of deformity.

Abstract P1-13-19: ESAM reduces anti-HER2 therapy sensitivity by activating mTOR pathway in HER2 positive breast cancer

Background: Trastuzumab combined with pertuzumab is the main therapy for HER2 positive breast cancer, but poor patient response due to drug resistance remains a clinical challenge. Organoids derived from tumor patients can highly maintain the heterogeneity of the original tumor, and have been used in drug sensitivity testing and new drug development. To screen for genes that associated with trastuzumab or pertuzumab drug resistance, this study used HER2-positive breast cancer organoids to establish a model of trastuzumab combined with pertuzumab and conducted high-throughput sequencing to screen the differential genes. We carried out further research to explore the effect of ESAM on drug sensitivity of HER2-targeted therapy and clarify the specific regulatory mechanisms and potential therapeutic targets of ESAM. Method: 8 HER2 positive breast cancer organoids were cultured. Immunohistochemistry, hematoxylin-eosin staining and Immunofluorescence were performed to identify the consistency between organoids and primitive tumors. According to drug sensitivity results of organoids to trastuzumab combined with pertuzumab, organoids were divided into a relatively sensitive group and a relatively insensitive group. Trastuzumab combined with pertuzumab was regularly used to stimulate the two groups. After 3 cycles, high-throughput transcriptome sequencing was used to evaluate their gene expression to find a gene responsible for trastuzumab and pertuzumab resistance. METABRIC and our center database were used to determine the prognostic value of ESAM. ESAM overexpression and knockdown stably transfected cell lines were constructed in SK-BR-3 and BT474 breast cancer cell lines by lentivirus. Colony formation assay, CCK-8 assay, organoid model and mouse xenograft model were conducted to examine the influence of ESAM on proliferation and trastuzumab or pertuzumab sensitization in vitro and in vivo. RNA-seq and GSEA analysis were performed to investigate the downstream pathways of ESAM. Western blot was used to confirm the relationship between ESAM and mTOR pathway. Small interfering RNA and mTOR/PI3K pathway inhibitors were used to confirm the function of mTOR in ESAM-induced drug resistance of trastuzumab. Results: HER2 positive breast cancer organoids can maintain the pathological characteristics of primitive tumors. The results of high-throughput transcriptome show that ESAM is significantly up-regulated in the relatively insensitive group compared to the relatively sensitive group. METABRIC and our center database suggest that high ESAM mRNA expression was associated with poor OS, RFS, DFS and PFS of HER2-positive breast cancer patients. CCK-8 and cell colony formation assay confirm that ESAM can promote the proliferation of HER2-positive breast cancer cells and inhibit the drug sensitivity of HER2-positive breast cancer cells to trastuzumab and pertuzumab. GSEA analysis shows high ESAM can activate mTORC1 signaling pathway. Western blotting analysis proves the expression of ESAM is positively correlated with mTOR pathway. Inhibition of mTOR pathway in ESAM overexpression cells can suppress ESAM-mediated proliferation and reverse the drug sensitivity of cells to trastuzumab and pertuzumab. In vivo, overexpression of ESAM can promote the proliferation of mouse mammary tumors and reduce the sensitivity of mouse mammary tumors to trastuzumab, combined use of PI3K inhibitor could reverse drug sensitivity of mouse mammary tumors to trastuzumab. Conclusion: High ESAM expression is associated with poor prognosis in patients with HER2 positive breast cancer. ESAM can activate mTOR pathway, promote cell proliferation and reduce the sensitivity of HER2 positive breast cancer cells to trastuzumab and pertuzumab, which can be inhibited by the application of PI3K/mTOR inhibitors. Keywords: ESAM; HER2 positive breast cancer; HER2 targeted therapy; mTOR; drug sensitivity.

Citation Format: Jiong Wu, Xujie Zhou, Yayun Chi, Jingyan Xue. ESAM reduces anti-HER2 therapy sensitivity by activating mTOR pathway in HER2 positive breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-13-19.

Abstract P1-13-05: Extracellular vesicles-transported lncRNA BCDR1 promotes tumor cell proliferation and therapy resistance via upregulating G1/S-phase transition in breast cancer

Background Extracellular vesicles (EVs), secreted by tumor cells for intercellular communication, play an important role in breast cancer progression. Previous studies have proved that lncRNA could use EVs to transmit signals and affect the progression and treatment of breast cancer. In addition, a previous study has found that, in HER2 therapy-resistant tumors, CDK4/6 activity and cell cycle progression genes were involved and might serve as treatment targets. However, recent clinical trials were not supportive of the use of CDK4/6 inhibitors in HER2 enriched internal subtypes of breast cancer. In this study, we aim to explore the role of EVs-transported long noncoding RNA BCDR1 in the promotion of cell cycle progression in HER2-positive breast cancer, exploring a new potential target in combination with CDK4/6 inhibitor and anti-HER2 treatment. Methods Samples were collected from patients with HER2 overexpression receiving neoadjuvant therapy. RNA-seq was performed to identify differentially expressed RNAs between pathological complete response (pCR) and non-pCR group. In addition, serum extracellular vesicles were collected and determined through RNA-seq. The drug response and proliferation rate of tumor cells were measured in breast cancer cells (HCC-1954, BT-474 and MCF-7). Quantitative RT-PCR (qRT-PCR) was used to detect the expression levels of BCDR1 and its potential target genes. RNA-seq and GSEA analysis was carried out to determine the target pathways regulated by BCDR1. DNA fiber assay, mass spectrometry, and flow cytometry were used to understand the underlying mechanism of BCDR1. Results Core needle biopsy tissues from HER2-positive breast cancer patients with any ER status were collected before NAC. Among genes differentially overexpressed, BCDR1 was found to be downregulated in pCR group compared with non-pCR group. BCDR1 was also elevated in plasma EVs in the non-pCR group. In addition, overexpression of BCDR1 in breast cancer cells promoted cell proliferation and HER2 treatment resistance. Through pathway analysis, we found BCDR1 could facilitate G1/S-phase transition. Flow cytometry confirmed these findings. We also noticed that proteins that regulate DNA licensing including minichromosome maintenance proteins (MCMs) were enriched in BCDR1 overexpression cells. Through DNA fiber assay, we confirmed that BCDR1 could promote DNA replication initiation. Interestingly, under CDK4/6 inhibitor treatment, BCDR1 was induced, unrevealing an internal treatment-resistant mechanism in these tumor cells. Through EVs RT-qPCR, we found BCDR1 could transport from high expression cells to low, with the same biological function. We also explored antisense oligonucleotide (ASO) use in the inhibition of BCDR1 biological function and transportation. Conclusion BCDR1 promotes cell proliferation and therapy resistance via upregulating DNA licensing in breast cancer. BCDR1 could transported through EVs with same biological function. This study also suggests that BCDR1 could serve as a biomarker and therapeutic target in breast cancer.

Citation Format: Qi Zhang, Bingqiu Xiu, Yayun Chi, Jiong Wu. Extracellular vesicles-transported lncRNA BCDR1 promotes tumor cell proliferation and therapy resistance via upregulating G1/S-phase transition in breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-13-05.

Abstract P1-07-07: Cross-talk of Four Types of RNA Modification Proteins with Adenosine Reveals the Landscape of Multivariate Prognostic Patterns in Breast Cancer

Background: BRCA is the most common malignant tumour, and its heterogeneity is one of its major characteristics. m6A, m1A, APA, and A-to-I RNA editing constitute the four most common adenosine-associated RNA modifications and represent the most typical and critical forms of epigenetic regulation contributing to the immunoinflammatory response, tumorigenesis and tumour heterogeneity. However, the cross-talk and potential combined profiles of these RMPs in multivariate prognostic patterns of BRCA remain unknown. Methods: A total of 48 published RMPs were analysed and found to display significant expression alterations and genomic mutation rates between tumour and normal tissues in the TCGA-BRCA cohort. Data from 4188 BRCA patients with clinical outcomes were downloaded from the GEO, METABRIC and TCGA databases, normalized and merged into one cohort. The prognostic value and interconnections of these RMPs were also studied. The four PRGs with the greatest prognostic value were then selected to construct diverse RMP-associated prognostic models through uniCox, differential expression analysis, LASSO regression and multiCox. Alterations in biological functional pathways, genomic mutations, immune infiltrations, RNAss scores and drug sensitivities among different models, as well as their prognostic value, were then explored. Results: Utilizing a large number of samples and a comprehensive set of genes contributing to adenosine-associated RNA modification, our study revealed the joint potential bio-functions and underlying features of these diverse RMPs and provided effective models (PRG clusters, gene clusters and the risk model) for predicting the clinical outcomes of BRCA. The individuals with higher risk scores showed poor prognoses, cell cycle function enrichment, upregulation of stemness scores, higher TMBs, immune activation and specific drug resistance. This work highlights the significance of comprehensively examining post-transcriptional RNA modification genes. Conclusions: Here, we designed and verified an advanced forecasting model to reveal the underlying links between BRCA and RMPs and precisely predict the clinical outcomes of multivariate prognostic patterns for individuals.

Citation Format: Xuliren Wang, Min Xiong, Bingqiu Xiu, Jiong Wu, Yayun Chi. Cross-talk of Four Types of RNA Modification Proteins with Adenosine Reveals the Landscape of Multivariate Prognostic Patterns in Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-07-07.

Abstract P5-02-41: UBE2E3 promotes the progression of HER2-positive breast cancer and influences the efficacy of targeted therapy via EGFR stabilization

Background: In the past 20 years, the efficacy and prognosis of HER2-positive breast cancer have significantly improved. However, nearly 50% of patients still have residual invasive tumors after chemotherapy combined with dual-targeted neoadjuvant therapy, especially for those with disease progression during treatment. A lack of effective therapeutic regimens results from the failure of targeted therapy, whose heterogeneity is especially worthy of our attention. The aim of this study was to look for efficacy markers and investigate new drug-resistance mechanisms. Methods: Firstly, the high-throughput sequencing data from 81 patients who received neoadjuvant chemotherapy TCbH (paclitaxel + carboplatin + trastuzumab) was analyzed by the efficacy outcomes. They were divided into 8 patients with stable or progressive disease (SD/PD), 35 with partial response (PR), and 38 with pathological complete remission (pCR). Then, UBE2E3 was chosen from the different expression genes between SD/PD and pCR based on efficacy results and the weighted gene co-expression network (WGCNA). UBE2E3 clinical correlations were investigated using publicly available data from The Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), and UBE2E3 was validated using immunohistochemistry (IHC) on 200 HER2-positive breast cancer tissue chips. Further, the UBE2E3 knockdown and overexpression stable transfer cell lines were constructed, and the effects of UBE2E3 on cell proliferation, clone formation, and drug sensitivity were verified by live cell imaging, the CCK8 assay, plate cloning, and IC50 assays, respectively. The tumor growth of UBE2E3 in vivo was investigated by an in situ transplantation tumor assay in nude mice. Meanwhile, the p-RB assay of mouse tissues by IHC was used to explore the effect of UBE2E3 on cell proliferation. RNA-seq was used to screen the downstream molecules of UBE2E3. Western blotting was used to verify the results of bioinformatics analysis and to explore the downstream key molecules. The protease inhibitor MG132 and actinomycin CHX were used to look at the effect on the stability of the target protein. Immunoprecipitation and silver staining assays were used to find interacting proteins with the UBE2E3. Results: Ten hub-genes which were efficacy-related were identified by WGCNA analysis, in which UBE2E3 was highly expressed in the SD/PD group (p < 0.05). In HER2-positive breast cancer, high expression of UBE2E3 was associated with poor prognosis and decreased disease-free survival both in public data and Fudan University Shanghai Cancer Center (FUSCC) data [HR 2. 36, (1.25–4.47), p < 0.05]. The experimental results demonstrated that UBE2E3 promoted the proliferation of HER2-positive breast cancer cells, enhanced clone formation, and resisted lapatinib’s treatment in cellular phenotype; and that UBE2E3 promoted tumor growth in vivo and upregulated the expression of p-RB. The differentially expressed genes’ sets of the RNA-seq between overexpressed cell lines and control showed that overexpressing UBE2E3 activated the EGFR pathway. Further, an immunoblot assay confirmed that UBE2E3 positively regulated EGFR levels and activated the downstream MAPK pathway. The proteasome inhibitor MG132 and CHX assays showed that UBE2E3 could stabilize EGFR proteins. The co-immunoprecipitation and silver staining assays showed that UBE2E3 stabilized EGFR proteins by interacting with c-Cbl. Conclusion: UBE2E3 could negatively affect the efficacy of HER2-positive breast cancer therapy and is significantly associated with poor prognosis. UBE2E3 may serve as a potential marker of efficacy and prognosis for HER2-positive breast cancer in the future. Therapeutic efficacy is affected by UBE2E3, which binds to c-Cbl and causes upregulation of EGFR expression in vivo, which in turn causes the MAPK pathway to be activated and tumor growth to be pushed up.

Citation Format: Pei Li, Wei-Ru Chi, Bingqiu Xiu, Qi Zhang, Liyi Zhang, Ming Chen, Jingyan Xue, Xiaoyan Huang, Yayun Chi, Jiong Wu. UBE2E3 promotes the progression of HER2-positive breast cancer and influences the efficacy of targeted therapy via EGFR stabilization [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-02-41.

Abstract P1-05-33: RNA in Extracellular vesicles used for the prediction of distant metastasis of breast cancer and the function of TGM2 in promoting breast cancer development

Background: Extracellular vesicles (EVs) can be released by living cells during the process of tumor metastasis. Since EVs could contain various of molecular with high stability, a growing number of evidences indicated that those molecular can be utilized as biomarkers of liquid biopsy for metastatic prediction. Therefore, we aimed to identify genes and build a model that can predict the risk of metastasis in breast cancer patients with acceptable sensitivity and accuracy. Methods: Pretreatment plasma EV-RNAs of patients diagnosed at Fudan University Shanghai Cancer Center from 2017 to 2018 were extracted and analyzed by next generation sequencing (NGS) and bioinformatics, including breast cancer patients (n=114) and benign cases (n=18). Weighted correlation network analysis (WGCNA) was utilized to determine the relationship between clinical features and genes. The Kaplan-Meier was used for survival analysis in public database. By 100 times of 5 folds cross-validation, we used logistic regression analysis to set up the model. The receiver operating characteristic curve (ROC) and area under curve (AUC) were used to assess the predicted capacity of the model. QRT-PCR was conducted to further confirm the expression of genes selected by the predicting model in 175 breast cancer patients with and without metastasis, along with 5 EV-RNAs of tumor samples and paired normal adjacent breast tissues. The functions of candidate genes on cell proliferation, metastasis, and invasion were determined by a series of in vitro experiments in cancer lines. RNA sequencing and bioinformatic analysis were performed to explore the mechanism of the candidate genes. Moreover, co-immunoprecipitation (Co-IP) was used to reveal interacting proteins. Results: WGCNA screened 40 hub genes which were significantly associated with the distant metastasis in patients with breast cancer. A total of 207 upregulated genes were identified in patients with distant metastasis. After intersection, 6 genes were selected. Survival analysis suggested that high expression of IGFBP5, BCL6B, TGM2, and SH3PXD2A were correlated with poor distant metastasis-free survival (DMFS). The metastasis predicting model built based on those genes showed an AUC value of 0.923 with diagnostic accuracy of 91.2%. In the validation cohort, data showed the AUC value of each single gene were 0.835, 0.818, 0.845, 0.834, for TGM2, IGFBP5, BCL6B, and SH3PXD2A respectively. Among those four genes, TGM2 was significantly upregulated with clinical stages and correlated with poor prognosis. Moreover, TGM2 showed the highest abundance in tumor tissue EVs. Functional experiments revealed that TGM2 promoted breast cancer proliferation, metastasis, and invasion in vitro. The initially upregulated expression of TGM2 in EVs of cell lines was significantly decreased by adding the exosome release inhibitor GW4869. In addition, EVs from TGM2 overexpressed cells promoted cell migration and invasion of wild-type cells. Mechanistically, TGM2 was positively correlated with EMT, Hedgehog and IL6-JAK-STAT3 pathways. Co-IP assay found that TGM2 interacted with TMF1, which was an effector for degradation of STAT3 through the ubiquitin-proteasome pathway. Interfering the expression of TMF1 remarkably promoted the migration ability of cells and reversed by TGM2 overexpression. Conclusion: Based on the plasma EV-RNAs, we constructed a model with promising predicted capacity of distant metastasis in patients with breast cancer. TGM2, as the most effective predictor, can promote the progression and metastasis of breast cancer by targeting TMF1/STAT3. Key words Breast Cancer; Extracellular vesicles; Metastasis; Prediction model; TGM2

Citation Format: Jiong Wu, Yayun Chi. RNA in Extracellular vesicles used for the prediction of distant metastasis of breast cancer and the function of TGM2 in promoting breast cancer development [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-05-33.

Abstract P5-02-53: P95HER2 Expression in HER2-Positive Breast Cancer

Background: -HER2-positive breast cancer subtype accounted for around 15-20% of all breast cancer. -The introduction of HER2-targeted therapy such as trastuzumab and pertuzumab has remarkably increased the patients’ prognosis of HER2-positive breast cancer. -However, resistance exists due to impaired drug binding to HER2 receptor and constitutive activation of HER2 downstream signaling pathways. -P95HER2 isoform is a truncated form of HER2 that retains the C terminal domain but lacks an N terminal trastuzumab binding site, leading to trastuzumab resistance in HER2-positive breast cancer. -A new P95HER2 antibody is developed to target the extracellular domain of p95HER2 in formalin-fixed paraffin-embedded (FFPE) HER2-positive breast cancer tissues by using hematoxylin and eosin (HE) staining method. Objectives: To evaluate the expression of P95HER2 and its clinicopathological characteristics in HER2-positive breast cancer. Methods: We assessed 68 HER2-positive patients (IHC 3+ or IHC 2+/in situ hybridization [ISH]+) from Fudan University Shanghai Cancer Center (FUSCC) who underwent breast cancer surgery and were treated with adjuvant chemotherapy (taxane or anthracycline or combination) plus trastuzumab from 2014 to 2016. P95HER2 HE antibody is provided by Simcere Pharma. In this study, we compared 27 patients with primary trastuzumab resistance with 41 non-relapse breast cancer patients. 14 patients have not received trastuzumab targeted therapy. P95HER2 staining of either 1+, 2+ or 3+ observed in any tumor area in HE slides was considered to be P95 HER2 positive. Chi-square test was used to determine the relationship between P95HER2 expression of patients’ characteristics. The main outcome measures were disease free-survival (DFS), distant disease-free survival (DDFS) and overall survival (OS) by using log-rank test. Univariable and multivariable Cox regression analyses were used to identify independent factors related to prognosis. Results: From 2014 to 2016, we assessed the expression of P95HER2 expression in 68 HER2 positive breast cancer patients from FUSCC. Median follow-up was 45 months. In our study, 19 (27.9%) were P95HER2 positive. P95HER2 positive expression rate is higher in premenopausal patients than in postmenopausal patients (68.4% vs 38.8%, P= 0.028). Univariable analysis showed that higher T-stage (P= 0.018), higher N-stage (P= 0.001) and P95HER2 positive expression (P= 0.033) were associated with worse DDFS. Multivariable analysis showed that higher T-stage (hazard ratio, 6.019; 95% CI, 1.205-30.078; P= 0.029) and P95HER2 positive (hazard ratio, 2.349; 95%CI, 1.03-5.358; P= 0.042) independently predicted worse DDFS. P95HER2 positive was significantly associated with shorter 5-year DDFS (42.1% vs 67.6%, P= 0.028), but has no significant difference in DFS (36.8% vs 59.5%, P= 0.072) and OS (74.8% vs 81.2%, P= 0.685). Conclusions: P95HER2 positive was found more in premenopausal patients and was associated with a higher metastasis rate, indicating that P95HER2 expression tends to be a more aggressive isoform type of HER2-positive breast cancer. P95HER2 may serve as a therapeutic target for anti-HER2 therapy.

Citation Format: Chih Wan Goh, Liyi Zhang, Wei-Ru Chi, Bingqiu Xiu, Jiajian Chen, Wenqing Yang, Chunxia Ao, Jianxing Tang, Jingyan Xue, Yayun Chi, Jiong Wu. P95HER2 Expression in HER2-Positive Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-02-53.

Abstract P2-16-04: MNX1 promotes tumor sensitivity to HER2-targeted therapy in HER2-positive breast cancer

Background: Female breast cancer has been the world’s leading cancer incidence among women. HER2-positive breast cancer accounts for about 15%~20% of all breast cancer, with a high degree of malignancy and easy metastasis and recurrence. With the development of medical technology and the continuous innovation of HER2 targeting drugs, patients with HER2-positive breast cancer have more treatment options and their prognosis had been greatly improved. However, there is still a lack of biomarkers for HER2-positive early breast cancer in clinical practice. Methods: This study prospectively collected single-center (Fudan University Shanghai Cancer Center, FUSCC) preoperative core needle biopsy samples of breast cancer patients from July 2017 to July 2018 who received neoadjuvant paclitaxel, carboplatin plus with trastuzumab (PCH). The patients were divided into pCR and non-PCR groups, and 81 patients were enrolled. The differential expression of genes was screened and validated by RNA-seq. The gene expression data for GSE181574 (this database has a total of 105 cases of breast cancer tissue samples were collected by core needle biopsy before neoadjuvant treatment. 52 cases underwent Ado-trastuzumab emtansine plus pertuzumab, 9 cases of paclitaxel plus trastuzumab, and 44 cases of paclitaxel plus trastuzumab and pertuzumab), GSE52707 (SK-BR-3 Lapatinib resistance cell group vs control group), and GSE15043 (BT474 Herceptin-resistant cell group vs control group), were downloaded from the Gene Expression Omnibus (GEO) database. Cell cloning formation, proliferation assay, and drug sensitivity experiments were conducted in MNX1 ectopic and knockdown cell lines. Co-IP assay, RNA-Seq, and ChIP-Seq analysis were used to explore the downstream pathways that MNX1 might be involved. Results: High-throughput sequencing results of core needle biopsy samples from 81 HER2-positive breast cancer patients were divided into pCR and non-pCR groups. Using DEseq2 packet analysis to screen differentially expressed genes, P-value < 0.05, | log2FoldChange | > 1 as the filter, there were 620 up-regulated genes and 715 down-regulated genes in the pCR group. The same method was used for the analysis of the GSE181574 data set. Combined the two datasets used P values and log2FoldChange (P-value < 0.05, | log2FoldChange | > 1.2) as selection criteria, we found the MNX1 and PNMT expressions were significantly higher in the pCR group. Subsequently, differential analysis of GSE52707 and GSE15043 datasets showed that MNX1 and PNMT expression levels were reduced in drug-resistant cell lines. Considering the P-value and | log2FoldChange |, we ultimately selected motor neuron and pancreatic homeobox 1(MNX1) gene as the target factors for follow-up studies. In the cloning formation and proliferation assay, overexpression of MNX1 inhibits proliferation and clonal formation of HER2-positive breast cancer cells. In the drug sensitivity experiments overexpression of MNX1 enhances the sensitivity of HER2-positive breast cancer cells to tyrosine kinase inhibitors (TKI) such as lapatinib and pyrotinib. MNX1 knockdown reduces the sensitivity of HER2-positive breast cancer cells to TKI. Through RNA-seq and ChIP-seq, we found that CD-M6PR might be a downstream target gene regulated by MNX1. Verification by Dual-Luciferase Reporter Assay MNX1 was found to positively regulate CD-M6PR transcription. By Co-IP assay, it was found that MNX1 interacted with EEF1D, and EEF1D stabilized MNX1. MNX1 and CD-M6PR affect the proliferation and drug sensitivity of breast cancer cells by down-regulating the PI3K-AKT-mTOR pathway. Conclusion: Overexpression of MNX1 increases the sensitivity of HER-2 positive cells to TKI. MNX1 binds to EEF1D and is stabilized by EEF1D. MNX1 positively regulates M6PR and affects the proliferation of breast cancer cells and the sensitivity of breast cancer cells to TKI through the PI3K-AKT-mTOR pathway.

Citation Format: Wei-Ru Chi, Bingqiu Xiu, Min Xiong, Pei Li, Qi Zhang, Lun Li, Jianjing Hou, Xujie Zhou, Yuting Sang, Ming Chen, Liyi Zhang, Jingyan Xue, Yayun Chi, Jiong Wu. MNX1 promotes tumor sensitivity to HER2-targeted therapy in HER2-positive breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-16-04.

LINC00478-derived novel cytoplasmic lncRNA LacRNA stabilizes PHB2 and suppresses breast cancer metastasis via repressing MYC targets

BACKGROUND

Metastasis is the predominant cause of mortality in patients with breast cancer. Long noncoding RNAs (lncRNAs) have been shown to drive important phenotypes in tumors, including invasion and metastasis. However, the lncRNAs involved in metastasis and their molecular and cellular mechanisms are still largely unknown.

METHODS

The transcriptional and posttranscriptional processing of LINC00478-associated cytoplasmic RNA (LacRNA) was determined by RT-qPCR, semiquantitative PCR and 5'/3' RACE. Paired-guide CRISPR/cas9 and CRISPR/dead-Cas9 systems was used to knock out or activate the expression of LacRNA. Cell migration and invasion assay was performed to confirm the phenotype of LacRNA. Tail vein model and mammary fat pad model were used for in vivo study. The LacRNA-PHB2-cMyc axis were screened and validated by RNA pulldown, mass spectrometry, RNA immunoprecipitation and RNA-seq assays.

RESULTS

Here, we identified a novel cytoplasmic lncRNA, LacRNA (LINC00478-associated cytoplasmic RNA), derived from nucleus-located lncRNA LINC00478. The nascent transcript of LINC00478 full-length (LINC00478_FL) was cleaved and polyadenylated, simultaneously yielding 5' ends stable expressing LacRNA, which is released into the cytoplasm, and long 3' ends of nuclear-retained lncRNA. LINC00478_3'RNA was rapidly degraded. LacRNA significantly inhibited breast cancer invasion and metastasis in vitro and in vivo. Mechanistically, LacRNA physically interacted with the PHB domain of PHB2 through its 61-140-nt region. This specific binding affected the formation of the autophagy degradation complex of PHB2 and LC3, delaying the degradation of the PHB2 protein. Unexpectedly, LacRNA specifically interacted with PHB2, recruited c-Myc and promoted c-Myc ubiquitination and degradation. The negatively regulation of Myc signaling ultimately inhibited breast cancer metastasis. Furthermore, LacRNA and LacRNA-mediated c-Myc signaling downregulation are significantly associated with good clinical outcomes, take advantage of these factors we constructed a prognostic predict model.

CONCLUSION

Therefore, our findings propose LacRNA as a potential prognostic biomarker and a new therapeutic strategy.

Development and validation of novel risk prediction models of breast cancer based on stanniocalcin‐1 level

PURPOSE

The function of stanniocalcin-1 (STC-1) in the oncogenesis and progression of tumors has been extensively studied. The purpose of this study was to investigate the relationship between secreted STC-1 and prognosis in patients with breast cancer (BC) and to determine whether STC-1 could be a key prognostic factor in BC.

METHODS

The STC-1 level was measured by ELISA and clinical data from 1210 female patients with BC were used to develop and validate nomograms. We then verified the models through the plotting of ROC curves and calibration curves, calculating the C-index, and performing decision curve analyses (DCA).

RESULTS

The level of STC-1 in the peripheral plasma was significantly correlated with the T stage, N stage, clinical stage, grade, hormone receptors, HER-2 status, and tumor subtype. Cox regression analyses revealed that estrogen receptor(ER) status, N stage, and STC-1 level were risk factors for overall survival (OS), whereas T stage, N stage, and STC-1 level were independent prognostic factors for distant disease-free survival (DDFS) and disease-free survival (DFS). Both the ROC curve and the C-index confirmed the high resolution of these models, while the DCA identified the feasibility of their practical application. In addition, the calibration curves indicated good consistency between the predicted and actual survival rates.

CONCLUSION

Nomograms were created based on STC-1 levels for 3-, 5-, and 7-year OS, DDFS, and DFS of patients with BC respectively. As a key prognostic factor for BC, peripheral blood STC-1 level can be used clinically as a liquid biopsy indicator.

Immunosuppressive lncRNA LINC00624 promotes tumor progression and therapy resistance through ADAR1 stabilization

BACKGROUND

Despite the success of HER2-targeted therapy in achieving prolonged survival in approximately 50% of treated individuals, treatment resistance is still an important challenge for HER2+ breast cancer (BC) patients. The influence of both adaptive and innate immune responses on the therapeutic outcomes of HER2+BC patients has been extensively demonstrated.

METHODS

Long non-coding RNAs expressed in non-pathological complete response (pCR) HER2 positive BC were screened and validated by RNA-seq. Survival analysis were made by Kaplan-Meier method. Cell death assay and proliferation assay were performed to confirm the phenotype of LINC00624. RT-qPCR and western blot were used to assay the IFN response. Xenograft mouse model were used for in vivo confirmation of anti-neu treatment resistance. RNA pull-down and immunoblot were used to confirm the interaction of ADAR1 and LINC00624. ADAR1 recombinant protein were purified from baculovirus expression system. B16-OVA cells were used to study antigen presentation both in vitro and in vivo. Flow cytometry was used to determine the tumor infiltrated immune cells of xenograft model. Antisense oligonucleotides (ASOs) were used for in vivo treatment.

RESULTS

In this study, we found that LINC00624 blocked the antitumor effect of HER2- targeted therapy both in vitro and in vivo by inhibiting type I interferon (IFN) pathway activation. The double-stranded RNA-like structure of LINC00624 can bind and be edited by the adenosine (A) to inosine (I) RNA-editing enzyme adenosine deaminase RNA specific 1 (ADAR1), and this editing has been shown to release the growth inhibition and attenuate the innate immune response caused by the IFN response. Notably, LINC00624 promoted the stabilization of ADAR1 by inhibiting its ubiquitination-induced degradation triggered by β-TrCP. In contrast, LINC00624 inhibited major histocompatibility complex (MHC) class I antigen presentation and limited CD8+T cell infiltration in the cancer microenvironment, resulting in immune checkpoint blockade inhibition and anti-HER2 treatment resistance mediated through ADAR1.

CONCLUSIONS

In summary, these results suggest that LINC00624 is a cancer immunosuppressive lncRNA and targeting LINC00624 through ASOs in tumors expressing high levels of LINC00624 has great therapeutic potential in future clinical applications.

Cross-talk of four types of RNA modification proteins with adenosine reveals the landscape of multivariate prognostic patterns in breast cancer

Background: Breast cancer (BC) is the most common malignant tumour, and its heterogeneity is one of its major characteristics. N6-methyladenosine (m6A), N1-methyladenosine (m1A), alternative polyadenylation (APA), and adenosine-to-inosine (A-to-I) RNA editing constitute the four most common adenosine-associated RNA modifications and represent the most typical and critical forms of epigenetic regulation contributing to the immunoinflammatory response, tumorigenesis and tumour heterogeneity. However, the cross-talk and potential combined profiles of these RNA-modified proteins (RMPs) in multivariate prognostic patterns of BC remain unknown.

Methods: A total of 48 published RMPs were analysed and found to display significant expression alterations and genomic mutation rates between tumour and normal tissues in the TCGA-BRCA cohort. Data from 4188 BC patients with clinical outcomes were downloaded from the Gene Expression Omnibus (GEO), the Cancer Genome Atlas (TCGA), and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), normalized and merged into one cohort. The prognostic value and interconnections of these RMPs were also studied. The four prognosis-related genes (PRGs) with the greatest prognostic value were then selected to construct diverse RMP-associated prognostic models through univariate Cox (uniCox) regression analysis, differential expression analysis, Least absolute shrinkage and selection operator (LASSO) regression and multivariate Cox (multiCox) regression. Alterations in biological functional pathways, genomic mutations, immune infiltrations, RNAss scores and drug sensitivities among different models, as well as their prognostic value, were then explored.

Results: Utilizing a large number of samples and a comprehensive set of genes contributing to adenosine-associated RNA modification, our study revealed the joint potential bio-functions and underlying features of these diverse RMPs and provided effective models (PRG clusters, gene clusters and the risk model) for predicting the clinical outcomes of BC. The individuals with higher risk scores showed poor prognoses, cell cycle function enrichment, upregulation of stemness scores, higher tumour mutation burdens (TMBs), immune activation and specific drug resistance. This work highlights the significance of comprehensively examining post-transcriptional RNA modification genes.

Conclusion: Here, we designed and verified an advanced forecasting model to reveal the underlying links between BC and RMPs and precisely predict the clinical outcomes of multivariate prognostic patterns for individuals.

Stabilization of CCDC102B by Loss of RACK1 Through the CMA Pathway Promotes Breast Cancer Metastasis via Activation of the NF-κB Pathway

Background

Breast cancer is one of the leading causes of cancer-related death among women, and the pathological status of axillary lymph nodes is an important predictor of prognosis. However, the mechanism involved in this early stage of metastasis remains largely unknown.

Methods

Microarray analysis was used to carry out differential genomics analyses between matched pairs of metastatic sentinel lymph node tissues and breast primary tumors. The CRISPR/Cas9 gene editing system was used for in vivo screening by transplanting a loss-of-function cell pool into immunocompromised mice. MAGeCK was used to analyze the screening results. Survival analysis was performed via the Kaplan–Meier method. Cell proliferation, wound healing, migration and invasion assays were performed to confirm the phenotype. A tail vein model and subcutaneous xenotransplanted tumor model were used for the in vivo study. The relationship between coiled-coil domain containing 102B (CCDC102B) and receptor for activated C kinase 1 (RACK1) was examined using coimmunoprecipitation, mass spectrometry, nuclear protein extraction and immunofluorescence assays. The primary biological functions and pathways related to CCDC102B were enriched by RNA sequencing.

Results

We identified CCDC102B through screening and found that it was significantly upregulated in metastatic lesions in lymph nodes compared to matched primary tumors. Increased expression of CCDC102B promoted breast cancer metastasis in vitro and in vivo. Additionally, high expression of CCDC102B was correlated with poor clinical outcomes in breast cancer patients. We further identified that CCDC102B was stabilized by the loss of RACK1, a protein negatively correlated with breast cancer metastasis. Mechanistically, we found that RACK1 promoted CCDC102B lysosomal degradation by mediating chaperone-mediated autophagy (CMA). The aggressive behavior of CCDC102B in breast cancer cells could be reversed by the expression of RACK1. Moreover, CCDC102B was correlated with the significant enrichment of NF-κB pathway components. Overexpressing CCDC102B led to less interaction between RACK1 and IKKa. Thus, CCDC102B positively regulates the NF−κB pathway by interacting with RACK1.

Conclusion

Taken together, our findings uncover a novel role of CCDC102B in breast cancer metastasis. CCDC102B serves as a potential metastasis promoter by regulating the activation of the NF-κB pathway and can be degraded by RACK1 via CMA.