Changes in nitrogen metabolism of phosphorus-starved bloom-forming cyanobacterium Microcystis aeruginosa: Implications for nutrient management.

The surplus of nitrogen plays a key role in the maintenance of cyanobacterial bloom when phosphorus has already been limited. However, the interplay between high nitrogen and low phosphorus conditions is not fully understood. Nitrogen metabolism is critical for the metabolism of cyanobacteria. Transcriptomic analysis in the present study suggested that nitrogen metabolism and ribosome biogenesis were the two most significantly changed pathways in long-term phosphorus-starved bloom-forming cyanobacteria Microcystis aeruginosa FACHB-905. Notably, the primary glutamine synthetase/glutamate synthase cycle, crucial for nitrogen metabolism, was significantly downregulated. Concurrently, nitrogen uptake showed a marked decrease due to reduced expression of nitrogen source transporters. The content of intracellular nitrogen reservoir phycocyanin also showed a drastic decrease upon phosphorus starvation. Our study demonstrated that long-term phosphorus-starved cells also suffered from nitrogen deficiency because of the reduction in nitrogen assimilation, which might be limited by the reduced ribosome biogenesis and the shortage of adenosine triphosphate. External nitrogen supply will not change the transcriptions of nitrogen metabolism-related genes significantly like that under phosphorus-rich conditions, but still help to maintain the survival of phosphorus-starved cells. The study deepens our understanding about the survival strategies of Microcystis cells under phosphorus starvation and the mutual dependence between nitrogen and phosphorus, which would provide valuable information for nutrient management in the eutrophicated water body.

NUSAP1-LDHA-Glycolysis-Lactate feedforward loop promotes Warburg effect and metastasis in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by hypoxia and hypovascular tumor microenvironment. Nucleolar and spindle associated protein 1 (NUSAP1) is a microtubule-associated protein that is known to be involved in cancer biology. Our study aimed to investigate the role of NUSAP1 in glycolytic metabolism and metastasis in PDAC. Expression and prognostic value of NUSAP1 in PDAC and common gastrointestinal tumors was evaluated. The function of NUSAP1 in PDAC progression was clarified by single-cell RNA-seq and further experiments in vitro, xenograft mouse model, spontaneous PDAC mice model and human tissue microarray. The downstream genes and signaling pathways regulated by NUSAP1 were explored by RNA-Seq. And the regulation of NUSAP1 on Lactate dehydrogenase A (LDHA)-mediated glycolysis and its underlying mechanism was further clarified by CHIP-seq. NUSAP1 was an independent unfavorable predictor of PDAC prognosis that playing a critical role in metastasis of PDAC by regulating LDHA-mediated glycolysis. Mechanically, NUSAP1 could bind to c-Myc and HIF-1α that forming a transcription regulatory complex localized to LDHA promoter region and enhanced its expression. Intriguingly, lactate upregulated NUSAP1 expression by inhibiting NUSAP1 protein degradation through lysine lactylated (Kla) modification, thus forming a NUSAP1-LDHA-glycolysis-lactate feedforward loop. The NUSAP1-LDHA-glycolysis-lactate feedforward loop is one of the underlying mechanisms to explain the metastasis and glycolytic metabolic potential in PDAC, which also provides a novel insights to understand the Warburg effect in cancer. Targeting NUSAP1 would be an attractive paradigm for PDAC treatment.

Integrated physiological and metabolomic analysis reveals new insights into toxicity pathways of paraquat to Microcystis aeruginosa.

Chemical pollutants, such as herbicides, released into the aquatic environment adversely affect the phytoplankton community structure. While majority of herbicides are specifically designed to target photosynthetic processes, they also can be toxic to phytoplankton; however, despite the photosynthetic toxicity, some herbicides can target multiple physiological processes. Therefore, a full picture of toxicity pathway of herbicide to phytoplankton is necessary. In the present study, the cyanobacterium Microcystis aeruginosa was exposed to two levels (17 µg L-1 (EC10) and 65 µg L-1 (EC50)) of paraquat for 72 h. The physiological and metabolic responses were analyzed to elucidate the toxicity pathway and establish the adverse outcome pathway of paraquat to M. aeruginosa. The results revealed that enhanced glycolysis (upregulation of pyruvic acid level) and tricarboxylic acid cycle (upregulation of the levels of malic acid, isocitric acid and citric acid) exposed to EC10 level of paraquat, which probably acted as a temporary strategy to maintain a healthy energy status in M. aeruginosa cells. Meanwhile, the expressions of glutathione and benzoic acid were enhanced to scavenge the excessive reactive oxygen species (ROS). Additionally, the accumulation of pigments (chlorophyll a and carotenoid) might play a supplementary role in the acclimation to EC10 level paraquat treatment. In cells exposed to paraquat by EC50 level, the levels of SOD, CAT, glutathione and benzoic acid increased significantly; however, the ROS exceeded the tolerance level of antioxidant system in M. aeruginosa. The adverse effects were revealed by inhibition of chlorophyll a fluorescence, the decreases in several carbohydrates (e.g., glucose 1-phosphate, fructose and galactose) and total protein content. Consequently, paraquat-induced oxidative stress caused the growth inhibition of M. aeruginosa. These findings provide new insights into the mode of action of paraquat in M. aeruginosa.

Super-enhancer-driven TOX2 mediates oncogenesis in Natural Killer/T Cell Lymphoma.

BACKGROUND: Extranodal natural killer/T-cell lymphoma (NKTL) is an aggressive type of non-Hodgkin lymphoma with dismal outcome. A better understanding of disease biology and key oncogenic process is necessary for the development of targeted therapy. Super-enhancers (SEs) have been shown to drive pivotal oncogenes in various malignancies. However, the landscape of SEs and SE-associated oncogenes remain elusive in NKTL. METHODS: We used Nano-ChIP-seq of the active enhancer marker histone H3 lysine 27 acetylation (H3K27ac) to profile unique SEs NKTL primary tumor samples. Integrative analysis of RNA-seq and survival data further pinned down high value, novel SE oncogenes. We utilized shRNA knockdown, CRISPR-dCas9, luciferase reporter assay, ChIP-PCR to investigate the regulation of transcription factor (TF) on SE oncogenes. Multi-color immunofluorescence (mIF) staining was performed on an independent cohort of clinical samples. Various function experiments were performed to evaluate the effects of TOX2 on the malignancy of NKTL in vitro and in vivo. RESULTS: SE landscape was substantially different in NKTL samples in comparison with normal tonsils. Several SEs at key transcriptional factor (TF) genes, including TOX2, TBX21(T-bet), EOMES, RUNX2, and ID2, were identified. We confirmed that TOX2 was aberrantly overexpressed in NKTL relative to normal NK cells and high expression of TOX2 was associated with worse survival. Modulation of TOX2 expression by shRNA, CRISPR-dCas9 interference of SE function impacted on cell proliferation, survival and colony formation ability of NKTL cells. Mechanistically, we found that RUNX3 regulates TOX2 transcription by binding to the active elements of its SE. Silencing TOX2 also impaired tumor formation of NKTL cells in vivo. Metastasis-associated phosphatase PRL-3 has been identified and validated as a key downstream effector of TOX2-mediated oncogenesis. CONCLUSIONS: Our integrative SE profiling strategy revealed the landscape of SEs, novel targets and insights into molecular pathogenesis of NKTL. The RUNX3-TOX2-SE-TOX2-PRL-3 regulatory pathway may represent a hallmark of NKTL biology. Targeting TOX2 could be a valuable therapeutic intervene for NKTL patients and warrants further study in clinic.

Chemotherapy with the use of next-generation tyrosine kinase inhibitors based on measurable residual disease has the potential to avoid hematopoietic stem cell transplantation in treatment for adults with Philadelphia chromosome-positive acute lymphoblastic leukemia.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) as postremission treatment is recommended for Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL) in current guidelines. However, comparisons of later generation tyrosine kinase inhibitors (TKIs) plus chemotherapy with allo-HSCT have yielded similar outcomes. This meta-analysis was performed to evaluate allo-HSCT in first complete remission (CR1) versus chemotherapy for adult Ph+ ALL in the TKI era. METHODS: Pooled assessment of the hematologic and molecular complete response rates was performed after 3-month TKI treatment. Hazard ratios (HRs) were determined for disease-free survival (DFS) and overall survival (OS) benefit with allo-HSCT. The effect of measurable residual disease status on survival benefit was also analyzed. RESULTS: Thirty-nine retrospective and prospective single-arm cohort studies involving 5054 patients were included. Combined HRs indicated that in the general population, allo-HSCT favorably influenced DFS and OS. Achieving complete molecular remission (CMR) within 3 months after starting induction was a favorable survival prognostic factor regardless of whether the patient had undergone allo-HSCT. Among the patients with CMR, survival rates in the nontransplant subgroup were comparable with those in the transplant subgroup, with the estimated 5-year OS of 64% versus 58% and 5-year DFS of 58% versus 51%, respectively. The use of next-generation TKIs results in a higher proportion of patients achieving CMR (ponatinib 82% vs. imatinib 53%), while improving survival in nontransplant patients. CONCLUSION: Our novel findings suggest that combination chemotherapy plus TKIs leads to a comparable survival benefit as with allo-HSCT for MRD-negative (CMR) patients. This study provides novel evidence for allo-HSCT indications for Ph+ ALL in CR1 in the TKI era.

Proteomic and single-cell landscape reveals novel pathogenic mechanisms of HBV-infected intrahepatic cholangiocarcinoma.

Despite the epidemiological association between intrahepatic cholangiocarcinoma (ICC) and hepatitis B virus (HBV) infection, little is known about the relevant oncogenic effects. A cohort of 32 HBV-infected ICC and 89 non-HBV-ICC patients were characterized using whole-exome sequencing, proteomic analysis, and single-cell RNA sequencing. Proteomic analysis revealed decreased cell-cell junction levels in HBV-ICC patients. The cell-cell junction level had an inverse relationship with the epithelial-mesenchymal transition (EMT) program in ICC patients. Analysis of the immune landscape found that more CD8 T cells and Th2 cells were present in HBV-ICC patients. Single-cell analysis indicated that transforming growth factor beta signaling-related EMT program changes increased in tumor cells of HBV-ICC patients. Moreover, ICAM1+ tumor-associated macrophages are correlated with a poor prognosis and contributed to the EMT in HBV-ICC patients. Our findings provide new insights into the behavior of HBV-infected ICC driven by various pathogenic mechanisms involving decreased cell junction levels and increased progression of the EMT program.

Clinical and molecular profiling of EGFR-mutant lung adenocarcinomas transformation to small cell lung cancer during TKI treatment.

Introduction: Small cell lung cancer (SCLC) transformation serves as a significant mechanism of resistance to tyrosine kinase inhibitors (TKIs) in advanced non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. To address this clinical challenge, we conducted a retrospective analysis at Zhejiang University School of Medicine, the First Affiliated Hospital, focusing on patients with EGFR sensitizing mutations. Methods: A total of 1012 cases were included in this retrospective analysis. The cohort primarily consisted of patients with EGFR sensitizing mutations. Biopsy-confirmed small cell transformation was observed in seven patients, accounting for 0.7% of the cases. All patients in this subset were initially diagnosed with stage IV adenocarcinoma (ADC), with four cases classified as poorly differentiated and three as moderately to poorly differentiated ADC. EGFR exon 19 deletions were identified in five of these cases. Next-generation sequencing (NGS) was performed on seven cases, revealing mutations in the tumor protein p53 (TP53) gene in four cases and loss of the retinoblastoma1 (RB1) gene in three cases. Results: The median duration from the initial diagnosis to small cell transformation was 35.9 months (interquartile range: 12.1-84 months). Following small cell transformation during EGFR inhibition, all patients received etoposide/platinum-based treatment, leading to a median progression-free survival (PFS) of 4.7 months (interquartile range: 2.7-10.1 months). Notably, most patients in this series had poorly differentiated adenocarcinomas at the outset. TP53 mutations and RB1 loss were common genetic alterations observed in patients with small cell transformation in this cohort. Discussion: The findings underscore the clinical significance of SCLC transformation as a resistance mechanism to EGFR TKIs in NSCLC with EGFR mutations. The observed genetic alterations, including TP53 mutations and RB1 loss, suggest potential associations with the transformation process and warrant further investigation. Understanding the genetic landscape and clinical outcomes in patients experiencing small cell transformation can contribute to improved strategies for managing resistance in EGFR-mutant NSCLC.

Surgical management of monomorphic epitheliotropic intestinal T-cell lymphoma followed by chemotherapy and stem-cell transplant: A case report and review of the literature.

BACKGROUND: Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a rare and rapidly progressive intestinal T-cell non-Hodgkin lymphoma associated with a very poor prognosis and a median survival of 7 mo. Advances in the identification of MEITL over the last two decades have led to its recognition as a separate entity. MEITL patients, predominantly male, typically present with vague and nonspecific symptoms and diagnosis is predominantly confirmed at laparotomy. Currently, there are no standardized treatment protocols, and the optimal therapy remains unclear. CASE SUMMARY: We report a case of MEITL that was initially considered to be gastrointestinal stromal tumor (GIST) and Imatinib was administered for one cycle. The 62-year-old man presented with abdominal pain, abdominal distension, and weight loss of 20 pounds. Within 2 wk, the size of the mass considerably increased on computed tomography scans. The patient underwent surgery followed by chemotherapy with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) and stem-cell transplant. A correct diagnosis of MEITL was established based on postoperative pathology. Immunophenotypically, the neoplastic cells fulfilled the diagnostic criteria for MEITL as they were CD3+, CD4+, CD8+, CD56+, and TIA-1+. CONCLUSION: Given that MEITL has no predisposing factor and presents with vague symptoms with rapid progression, the concomitant presence of abdominal symptoms and B symptoms (weight loss, fever, and night sweats) with hypoalbuminemia, anemia, low lymphocytic count and endoscopic findings of diffuse infiltrating type lesions should alert physicians to this rare disease, especially when it comes to Asian patients. Immediate laparotomy should then be carried out followed by chemotherapy and stem-cell transplant.

EMLI-ICC: an ensemble machine learning-based integration algorithm for metastasis prediction and risk stratification in intrahepatic cholangiocarcinoma.

Robust strategies to identify patients at high risk for tumor metastasis, such as those frequently observed in intrahepatic cholangiocarcinoma (ICC), remain limited. While gene/protein expression profiling holds great potential as an approach to cancer diagnosis and prognosis, previously developed protocols using multiple diagnostic signatures for expression-based metastasis prediction have not been widely applied successfully because batch effects and different data types greatly decreased the predictive performance of gene/protein expression profile-based signatures in interlaboratory and data type dependent validation. To address this problem and assist in more precise diagnosis, we performed a genome-wide integrative proteome and transcriptome analysis and developed an ensemble machine learning-based integration algorithm for metastasis prediction (EMLI-Metastasis) and risk stratification (EMLI-Prognosis) in ICC. Based on massive proteome (216) and transcriptome (244) data sets, 132 feature (biomarker) genes were selected and used to train the EMLI-Metastasis algorithm. To accurately detect the metastasis of ICC patients, we developed a weighted ensemble machine learning method based on k-Top Scoring Pairs (k-TSP) method. This approach generates a metastasis classifier for each bootstrap aggregating training data set. Ten binary expression rank-based classifiers were generated for detection of metastasis separately. To further improve the accuracy of the method, the 10 binary metastasis classifiers were combined by weighted voting based on the score from the prediction results of each classifier. The prediction accuracy of the EMLI-Metastasis algorithm achieved 97.1% and 85.0% in proteome and transcriptome datasets, respectively. Among the 132 feature genes, 21 gene-pair signatures were developed to establish a metastasis-related prognosis risk-stratification model in ICC (EMLI-Prognosis). Based on EMLI-Prognosis algorithm, patients in the high-risk group had significantly dismal overall survival relative to the low-risk group in the clinical cohort (P-value < 0.05). Taken together, the EMLI-ICC algorithm provides a powerful and robust means for accurate metastasis prediction and risk stratification across proteome and transcriptome data types that is superior to currently used clinicopathological features in patients with ICC. Our developed algorithm could have profound implications not just in improved clinical care in cancer metastasis risk prediction, but also more broadly in machine-learning-based multi-cohort diagnosis method development. To make the EMLI-ICC algorithm easily accessible for clinical application, we established a web-based server for metastasis risk prediction (http://ibi.zju.edu.cn/EMLI/).

Cancer cell membrane-wrapped nanoparticles for cancer immunotherapy: A review of current developments.

Background: As the forefront of nanomedicine, bionic nanotechnology has been widely used for drug delivery in order to obtain better efficacy but less toxicity for cancer treatments. With the rise of immunotherapy, the combination of nanotechnology and immunotherapy will play a greater potential of anti-tumor therapy. Due to its advantage of homologous targeting and antigen library from source cells, cancer cell membrane (CCM)-wrapped nanoparticles (CCNPs) has become an emerging topic in the field of immunotherapy. Key scientific concepts of review: CCNP strategies include targeting or modulating the tumor immune microenvironment and combination therapy with immune checkpoint inhibitors and cancer vaccines. This review summarizes the current developments in CCNPs for cancer immunotherapy and provides insight into the challenges of transferring this technology from the laboratory to the clinic as well as the potential future of this technology. Conclusion: This review described CCNPs have enormous potential in cancer immunotherapy, but there are still challenges in terms of translating their effects in vitro to the clinical setting. We believe that these challenges can be addressed in the future with a focus on individualized treatment with CCNPs as well as CCNPs combined with other effective treatments.

Immunotherapy of cholangiocarcinoma: Therapeutic strategies and predictive biomarkers.

Cholangiocarcinoma (CCA) is a group of malignant heterogeneous cancer arising from the biliary tree. CCA has become a global health problem with rising incidence and mortality that threatens the health of human beings. The immune microenvironment of CCA is characterized by abundant cancer-associated fibroblast and suppressive immune components. The increasing body of knowledge and recent developments in transcriptomic studies have given insight into the immune landscape of CCA, paving the way for better application of immunotherapy. Immunotherapy mainly applies in a limited subset of CCA with deficient mismatch and high microsatellite instability. With limited response rates and treatment efficacy, researchers are looking into novel strategies on combination strategies and alternatives, such as immune vaccines and adoptive cell therapy. Biomarker identification is also critical for patient selection. We present an up-to-date summary of the current research on immunotherapy for CCA patients, covering pre-clinical and clinical exploration beyond immune checkpoint inhibitors, immune vaccines, and adoptive cell therapy. In addition, we review the promising biomarkers for CCA immunotherapy and discuss recent development.

HJURP regulates cell proliferation and chemo-resistance via YAP1/NDRG1 transcriptional axis in triple-negative breast cancer.

Triple-negative breast cancer is still a difficult point in clinical treatment at present, and a deep study of its pathogenesis has great clinical value. Therefore, our research mainly focuses on exploring the progression of triple-negative breast cancer and determines the important role of the HJURP/YAP1/NDRG1 transcriptional regulation axis in triple-negative breast cancer. We observed significantly increased HJURP expression levels in triple-negative breast cancer compared to other subtypes. HJURP could affect the level of ubiquitination modification of YAP1 protein and then regulate its downstream transcriptional activity. Mechanistically, we found that YAP1 positively regulates NDRG1 transcription by binding the promoter region of the NDRG1 gene. And HJURP/YAP1/NDRG1 axis could affect cell proliferation and chemotherapy sensitivity in triple-negative breast cancer. Taken together, these findings provide insights into the transcriptional regulation axis of HJURP/YAP1/NDRG1 in triple-negative breast cancer progression and therapeutic response.

Corrigendum: STAT5a Confers Doxorubicin Resistance to Breast Cancer by Regulating ABCB1.

[This corrects the article DOI: 10.3389/fonc.2021.697950.].

Sporoderm-Broken Spores of Ganoderma lucidum Sensitizes Ovarian Cancer to Cisplatin by ROS/ERK Signaling and Attenuates Chemotherapy-Related Toxicity.

Although platinum-based chemotherapeutics such as cisplatin are the cornerstone of treatment for ovarian cancer, their clinical application is profoundly limited due to chemoresistance and severe adverse effects. Sporoderm-broken spores of Ganoderma lucidum (SBSGL) have been reported to possess antitumor effects. However, the function and mechanism of SBSGL and its essential composition, ganoderic acid D (GAD), in the cisplatin therapy on ovarian cancer have yet to be investigated. Here, we investigated the combined effect of SBSGL and cisplatin in an ovarian tumor xenograft model. The results showed that combining SBSGL with cisplatin reduced tumor growth and ameliorated cisplatin-induced intestinal injury and myelosuppression. We also confirmed that GAD could enhance the therapeutic effect of cisplatin in SKOV3 and cisplatin-resistant SKOV3/DDP cells by increasing the intracellular reactive oxygen species (ROS). Mechanistically, we proved that ROS-mediated ERK signaling inhibition played an important role in the chemo-sensitization effect of GAD on cisplatin in ovarian cancer. Taken together, combining SBSGL with cisplatin provides a novel therapeutic strategy against ovarian cancer.

Super Enhancer-Mediated Upregulation of HJURP Promotes Growth and Survival of t(4;14)-Positive Multiple Myeloma.

Multiple myeloma is an incurable malignancy with marked clinical and genetic heterogeneity. The cytogenetic abnormality t(4;14) (p16.3;q32.3) confers aggressive behavior in multiple myeloma. Recently, essential oncogenic drivers in a wide range of cancers have been shown to be controlled by super-enhancers (SE). We used chromatin immunoprecipitation sequencing of the active enhancer marker histone H3 lysine 27 acetylation (H3K27ac) to profile unique SEs in t(4;14)-translocated multiple myeloma. The histone chaperone HJURP was aberrantly overexpressed in t(4;14)-positive multiple myeloma due to transcriptional activation by a distal SE induced by the histone lysine methyltransferase NSD2. Silencing of HJURP with short hairpin RNA or CRISPR interference of SE function impaired cell viability and led to apoptosis. Conversely, HJURP overexpression promoted cell proliferation and abrogated apoptosis. Mechanistically, the NSD2/BRD4 complex positively coregulated HJURP transcription by binding the promoter and active elements of its SE. In summary, this study introduces SE profiling as an efficient approach to identify new targets and understand molecular pathogenesis in specific subtypes of cancer. Moreover, HJURP could be a valuable therapeutic target in patients with t(4;14)-positive myeloma. SIGNIFICANCE: A super-enhancer screen in t(4;14) multiple myeloma serves to identify genes that promote growth and survival of myeloma cells, which may be evaluated in future studies as therapeutic targets.

STAT5a Confers Doxorubicin Resistance to Breast Cancer by Regulating ABCB1.

Chemoresistance is a daunting challenge to the prognosis of patients with breast cancer. Signal transducer and activator of transcription (STAT) 5a plays vital roles in the development of various cancers, but its function in breast cancer is controversial, and its role in chemoresistance in breast cancer remains unexplored. Here we identified STAT5a as a chemoresistance inducer that regulates the expression of ABCB1 in breast cancer and can be targeted by pimozide, an FDA-approved psychotropic drug. First, we found that STAT5a and ABCB1 were expressed at higher levels in doxorubicin-resistant cell lines and chemoresistant patients, and their expression was positively correlated. Then, we confirmed the essential roles of STAT5a and ABCB1 in doxorubicin resistance in breast cancer cells and the regulation of ABCB1 transcription by STAT5a. Subsequently, the efficacy of pimozide in inhibiting STAT5a and sensitizing doxorubicin-resistant breast cancer cells was tested. Finally, we verified the role of STAT5a in doxorubicin resistance in breast cancer and the efficacy of pimozide in reversing this resistance in vivo. Our study demonstrated the vital role of STAT5a in doxorubicin resistance in breast cancer. Targeting STAT5a might be a promising strategy for treating doxorubicin-resistant breast cancer. Moreover, repurposing pimozide for doxorubicin resensitization is attractive due to the safety profile of pimozide.

PLAC8 promotes adriamycin resistance via blocking autophagy in breast cancer.

Adriamycin (ADM) is currently one of the most effective chemotherapeutic agents in breast cancer treatment. However, growing resistance to ADM could lead to treatment failure and poor outcome. PLAC8 was reported as a novel highly conserved protein and functioned as an oncogene or tumour suppressor in various tumours. Here, we found higher PLAC8 expression was correlated with worse outcome and aggressive phenotype in breast cancer. Breast cancer patients with higher PLAC8 expression showed potential ADM resistance. In vitro experiments further confirmed that PLAC8 inhibited by siRNA or enforced overexpression by infecting pcDNA3.1(C)-PLAC8 plasmid correspondingly decreased or increased ADM resistance. Subsequently, we demonstrated that ectopic PLAC8 expression in MCF-7/ADMR cell blocked the accumulation of the autophagy-associated protein LC3 and resulted in cellular accumulation of p62. Rapamycin-triggered autophagy significantly increased cell response to ADM, while the autophagy inhibitor 3-MA enhanced ADM resistance. 3-MA and PLAC8 could synergistically cause ADM resistance via blocking the autophagy process. Additionally, the down-regulation of p62 by siRNA attenuated the activation of autophagy and PLAC8 expression in breast cancer cells. Thus, our findings suggest that PLAC8, through the participation of p62, inhibits autophagy and consequently results in ADM resistance in breast cancer. PLAC8/p62 pathway may act as novel therapeutic targets in breast cancer treatment and has potential clinical application in overcoming ADM resistance.

Myeloma-specific superenhancers affect genes of biological and clinical relevance in myeloma.

Multiple myeloma (MM) is an aggressive plasma cell neoplasm characterized by genomic heterogeneity. Superenhancers (SEs) are defined as large clusters of enhancers in close genomic proximity, which regulate genes for maintaining cellular identity and promote oncogenic transcription to which cancer cells highly addicted. Here, we analyzed cis-regulatory elements in MM samples with H3K27ac ChIP-seq, to identify novel SE-associated genes involved in the myeloma pathogenesis. SEs and their associated genes in cancerous tissue were compared with the control samples, and we found SE analysis alone uncovered cell-lineage-specific transcription factors and well-known oncogenes ST3GAL6 and ADM. Using a transcriptional CDK7 inhibitor, THZ1, coupled with H3K27ac ChlP-seq, we identified MAGI2 as a novel SE-associated gene of myeloma cells. Elevated MAGI2 was related to myelomagenesis with gradual increased expression from MGUS, SMM to newly diagnosed and relapsed MM. High prevalence of MAGI2 was also associated with poor survival of MM patients. Importantly, inhibition of the SE activity associated with MAGI2 decreased MAGI2 expression, inhibited cell growth and induced cell apoptosis. Mechanistically, we revealed that the oncogenic transcription factor, MAF, directly bound to the SE region and activated gene transcription. In summary, the discoveries of these acquired SEs-associated genes and the novel mechanism by which they are regulated provide new insights into MM biology and MAGI2-MAF-SE regulatory circuit offer potential novel targets for disease treatment.

Naringenin Regulates FKBP4/NR3C1/NRF2 Axis in Autophagy and Proliferation of Breast Cancer and Differentiation and Maturation of Dendritic Cell.

NRF2 is an important regulatory transcription factor involved in tumor immunity and tumorigenesis. In this study, we firstly identified that FKBP4/NR3C1 axis was a novel negative regulator of NRF2 in human breast cancer (BC) cells. The effect of FKBP4 appeared to be at protein level of NRF2 since it could not suppress the expression of NRF2 at mRNA level. Bioinformatics analysis and in vitro experiments further demonstrated that FKBP4 regulated NRF2 via regulating nuclear translocation of NR3C1. We then reported that naringenin, a flavonoid, widely distributed in citrus and tomato, could suppress autophagy and proliferation of BC cells through FKBP4/NR3C1/NRF2 signaling pathway in vitro and in vivo. Naringenin was also found to promote dendritic cell (DC) differentiation and maturation through FKBP4/NR3C1/NRF2 axis. Therefore, our study found that naringenin could induce inhibition of autophagy and cell proliferation in BC cells and enhance DC differentiation and maturation, at least in part, though regulation of FKBP4/NR3C1/NRF2 signaling pathway. Identification of FKBP4/NR3C1/NRF2 axis would provide insights for novel anti-tumor strategy against BC among tumor microenvironment.

H19/let­7/Lin28 ceRNA network mediates autophagy inhibiting epithelial­mesenchymal transition in breast cancer.

Long non­coding RNA (lncRNA) H19 and Lin28 protein have been shown to participate in various pathophysiological processes, including cellular proliferation, autophagy and epithelial­mesenchymal transition (EMT). A number of studies have investigated lncRNAs, microRNAs and mRNAs, and their roles in the initiation and progression of cancer, in doing so identifying competitive endogenous RNA (ceRNA) networks, including the H19/let­7/Lin28 network. However, whether the H19/let­7/Lin28 ceRNA network is involved in autophagy and EMT in breast cancer (BC) remains unclear. The present study demonstrated that the H19/let­7/Lin28 loop was required for the downregulation of autophagy in BC cells via western blot analysis, reverse transcription­quantitative PCR and autophagy flux monitoring. Using wound healing, migration and invasion assays, and morphological assays, the H19/let­7/Lin28 loop was revealed to promote EMT in BC cells. Moreover, the H19/let­7/Lin28 network was found to contribute to autophagy by inhibiting EMT in BC cells. To the best of our knowledge, the present study is the first to suggest the important roles of the H19/let­7/Lin28 ceRNA network in BC autophagy and EMT, thus providing insight for the use of these molecules as prognostic biomarkers and therapeutic targets in BC metastasis.