Bone marrow stromal cells dictate lanosterol biosynthesis and ferroptosis of multiple myeloma.

Ferroptosis has been demonstrated a promising way to counteract chemoresistance of multiple myeloma (MM), however, roles and mechanism of bone marrow stromal cells (BMSCs) in regulating ferroptosis of MM cells remain elusive. Here, we uncovered that MM cells were more susceptible to ferroptotic induction under the interaction of BMSCs using in vitro and in vivo models. Mechanistically, BMSCs elevated the iron level in MM cells, thereby activating the steroid biosynthesis pathway, especially the production of lanosterol, a major source of reactive oxygen species (ROS) in MM cells. We discovered that direct coupling of CD40 ligand and CD40 receptor constituted the key signaling pathway governing lanosterol biosynthesis, and disruption of CD40/CD40L interaction using an anti-CD40 neutralizing antibody or conditional depletion of Cd40l in BMSCs successfully eliminated the iron level and lanosterol production of MM cells localized in the Vk*MYC Vk12653 or NSG mouse models. Our study deciphers the mechanism of BMSCs dictating ferroptosis of MM cells and highlights the therapeutic potential of non-apoptosis strategies for managing refractory or relapsed MM patients.

Immunophenotypic clustering in paediatric acute myeloid leukaemia.

Acute myeloid leukaemia (AML) is a highly heterogeneous disease, exhibiting diverse subtypes according to the characteristics of tumour cells. The immunophenotype is one of the aspects acquired routinely through flow cytometry in the diagnosis of AML. Here, we characterized the antigen expression in paediatric AML cases across both morphological and molecular genetic subgroups. We discovered a subgroup of patients with unfavourable prognosis that can be immunologically characterized, irrespective of morphological FAB results or genetic aberrations. Cox regression analysis unveiled key antigens influencing the prognosis of AML patients. In terms of underlying genotypes, we observed that the antigenic profiles and outcomes of one specific group, primarily composed of CBFA2T3::GLIS2 and FUS::ERG, were analogous to the reported RAM phenotype. Overall, our data highlight the significance of immunophenotype to tailor treatment for paediatric AML.

circRNAs as prognostic markers in pediatric acute myeloid leukemia.

Circular RNAs (circRNAs) arise from precursor mRNA processing through back-splicing and have been increasingly recognized for their functions in various cancers including acute myeloid leukemia (AML). However, the prognostic implications of circRNA in AML remain unclear. We conducted a comprehensive genome-wide analysis of circRNAs using RNA-seq data in pediatric AML. We revealed a group of circRNAs associated with inferior outcomes, exerting effects on cancer-related pathways. Several of these circRNAs were transcribed directly from genes with established functions in AML, such as circRUNX1, circWHSC1, and circFLT3. Further investigations indicated the increased number of circRNAs and linear RNAs splicing were significantly correlated with inferior clinical outcomes, highlighting the pivotal role of splicing dysregulation. Subsequent analysis identified a group of upregulated RNA binding proteins in AMLs associated with high number of circRNAs, with TROVE2 being a prominent candidate, suggesting their involvement in circRNA associated prognosis. Through the integration of drug sensitivity data, we pinpointed 25 drugs that could target high-risk AMLs characterized by aberrant circRNA transcription. These findings underscore prognostic significance of circRNAs in pediatric AML and offer an alternative perspective for treating high-risk cases in this malignancy.

High-dose methotrexate pharmacokinetics and its impact on prognosis of paediatric acute lymphoblastic leukaemia patients: A population pharmacokinetic study.

This study delivers a comprehensive evaluation of the efficacy and pharmacokinetics of high-dose methotrexate (HDMTX) in a large cohort of Chinese paediatric acute lymphoblastic leukaemia patients. A total of 533 patients were included in the prognostic analysis. An association was observed between lower steady-state MTX concentrations (<56 µmol/L) and poorer outcomes in intermediate-/high-risk (IR/HR) patients. Subgroup analysis further revealed that this relationship between concentrations and prognosis was even more pronounced in patients with MLL rearrangements. In contrast, such an association did not emerge within the low-risk patient group. Additionally, utilizing population pharmacokinetic modelling (6051 concentrations from 815 patients), we identified the significant impact of physiological maturation, estimated glomerular filtration rate, sex and concurrent dasatinib administration on MTX pharmacokinetics. Simulation-based recommendations include a reduced dosage regimen for those with renal insufficiency and a specific 200 mg/kg dosage for infants under 1 year. The findings underscore the critical role of HDMTX in treating IR/HR populations and call for a reassessment of its application in lower-risk groups. An individualized pharmacokinetic dosage regimen could achieve the most optimal results, ensuring the largest proportion of steady-state concentrations within the optimal range.

Genome-Wide Bioinformatics Analysis of SWEET Gene Family and Expression Verification of Candidate PaSWEET Genes in Potentilla anserina.

Sugars act as the main energy sources in many fruit and vegetable crops. The biosynthesis and transportation of sugars are crucial and especially contribute to growth and development. SWEET is an important gene family that plays a vital role in plants' growth, development, and adaptation to various types of stresses (biotic and abiotic). Although SWEET genes have been identified in numerous plant species, there is no information on SWEETs in Potentilla anserina. In the present study, we performed a comprehensive genome-wide bioinformatics analysis and identified a total of 23 candidate PaSWEETs genes in the Potentilla anserina genome, which were randomly distributed on ten different chromosomes. The phylogenetic analysis, chromosomal location, gene structure, specific cis-elements, protein interaction network, and physiological characteristics of these genes were systematically examined. The identified results of the phylogenetic relationship with Arabidopsis thaliana revealed that these PaSWEET genes were divided into four clades (I, II, III, and IV). Moreover, tissue-specific gene expression through quantitative real-time polymerase chain reaction (qRT-PCR) validation exposed that the identified PaSWEETs were differentially expressed in various tissues (roots, stems, leaves, and flowers). Mainly, the relative fold gene expression in swollen and unswollen tubers effectively revealed that PaSWEETs (7, 9, and 12) were highly expressed (300-, 120-, and 100-fold) in swollen tubers. To further elucidate the function of PaSWEETs (7, 9, and 12), their subcellular location was confirmed by inserting them into tobacco leaves, and it was noted that these genes were present on the cell membrane. On the basis of the overall results, it is suggested that PaSWEETs (7, 9, and 12) are the candidate genes involved in swollen tuber formation in P. anserina. In crux, we speculated that our study provides a valuable theoretical base for further in-depth function analysis of the PaSWEET gene family and their role in tuber development and further enhancing the molecular breeding of Potentilla anserina.

Who are optimal candidates for primary tumor resection in patients with metastatic gastric adenocarcinoma? A population-based study.

BACKGROUND: The research aimed to construct a novel predictive nomogram to identify specific metastatic gastric adenocarcinoma (mGAC) populations who could benefit from primary tumor resection (PTR). METHOD: Patients with mGAC were included in the SEER database and divided into PTR and non-PTR groups. The Kaplan-Meier analysis, propensity score matching (PSM), least absolute shrink and selection operator (LASSO) regression, multivariable logistic regression, and multivariate Cox regression methods were then used. Finally, the prediction nomograms were built and tested. RESULTS: 3185 patients with mGAC were enrolled. Among the patients, 679 cases underwent PTR while the other 2506 patients didn't receive PTR. After PSM, the patients in the PTR group presented longer median overall survival (15.0 vs. 7.0 months, p < 0.001). Among the PTR group, 307 (72.9%) patients obtained longer overall survival than seven months (beneficial group). Then the LASSO logistic regression was performed, and gender, grade, T stage, N stage, pathology, and chemotherapy were included to construct the nomogram. In both the training and validation cohorts, the nomogram exhibited good discrimination (AUC: 0.761 and 0.753, respectively). Furthermore, the other nomogram was constructed to predict 3-, 6-, and 12-month cancer-specific survival based on the variables from the multivariate Cox analysis. The 3-, 6-, and 12-month AUC values were 0.794, 0.739, and 0.698 in the training cohort, and 0.805, 0.759, and 0.695 in the validation cohorts. The calibration curves demonstrated relatively good consistency between the predicted and observed probabilities of survival in two nomograms. The models' clinical utility was revealed through decision curve analysis. CONCLUSION: The benefit nomogram could guide surgeons in decision-making and selecting optimal candidates for PTR among mGAC patients. And the prognostic nomogram presented great prediction ability for these patients.

Comparative analysis of machine learning-based ultrasound radiomics in predicting malignancy of partially cystic thyroid nodules.

OBJECTIVE: To investigate the application of machine learning (ML) model-based thyroid ultrasound radiomics in the evaluation of malignancy in partially cystic thyroid nodules (PCTNs). METHODS: One hundred and ninety-two patients with 197 nodules PCTNs from January 2020 to December 2020 were retrospectively analyzed. Radiomics features were extracted based on hand-crafted features from the ultrasound images, and machine learning methods were used to build a classification model by radiomics features. The least absolute shrinkage and selection operator regression was applied to select the features of nonzero coefficients from radiomics features. The prediction performance of the established model was mainly evaluated by the area under the curve (AUC) and accuracy, sensitivity, and specificity. RESULTS: Nineteen radiomics features were extracted from the original images for each nodule. Eight ML classifiers were able to differentiate malignancy in PCTNs. The AUC, accuracy, sensitivity, and specificity of k-Nearest Neighbor (KNN) model were 0.909, 82.95%, 83.33%, and 89.90%, respectively, on the test cohort. The comparative result showed statistically equivalent performance for thyroid nodule diagnosis based on image fusion and single image. In addition, the ML-Based ultrasound radiomics system showed a better AUC as compared with ACR TI-RADS model and the ultrasound features model. CONCLUSION: The novel ultrasonic-based ML model has an important clinical value for predicting malignancy in PCTNs. It can provide clinicians with a preoperative non-invasive primary screening method for PCTN diagnosis to avoid unnecessary medical investment and improve treatment outcomes.

Chromatin accessibility landscape of relapsed pediatric B-lineage acute lymphoblastic leukemia.

For around half of the pediatric B-lineage acute lymphoblastic leukemia (B-ALL) patients, the molecular mechanism of relapse remains unclear. To fill this gap in knowledge, here we characterize the chromatin accessibility landscape in pediatric relapsed B-ALL. We observe rewired accessible chromatin regions (ACRs) associated with transcription dysregulation in leukemia cells as compared with normal B-cell progenitors. We show that over a quarter of the ACRs in B-ALL are in quiescent regions with high heterogeneity among B-ALLs. We identify subtype-specific and allele-imbalanced chromatin accessibility by integrating multi-omics data. By characterizing the differential ACRs between diagnosis and relapse in B-ALL, we identify alterations in chromatin accessibility during drug treatment. Further analysis of ACRs associated with relapse free survival leads to the identification of a subgroup of B-ALL which show early relapse. These data provide an advanced and integrative portrait of the importance of chromatin accessibility alterations in tumorigenesis and drug responses.

CXCL10 Recruitment of γδ T Cells into the Hypoxic Bone Marrow Environment Leads to IL17 Expression and Multiple Myeloma Progression.

In multiple myeloma (MM), bone marrow stromal cells (BMSC) shape a unique niche within the bone marrow, promoting T-cell dysfunction and driving MM progression; however, the precise underlying mechanisms remain elusive. Here, we show that BMSC-mediated reprogramming of MM cells led to heightened production of CXCL10. CXCL10 orchestrated the recruitment of γδ T cells into the bone marrow, and this was observed in both the Vk*MYC and 5TGM1 mouse models of MM, as well as in patients experiencing refractory or relapsed MM. Furthermore, the dysfunctional γδ T cells in the MM bone marrow niche exhibited increased PD-1 expression and IL17 production. In the Vk*MYC mouse model, MM-associated bone lesions and mortality were markedly alleviated in Tcrd-/- mice, and MM disease progression could be rescued in these mice upon transplantation of γδ T cells expanded from wild-type mice, but not from Il17-/- mice. Mechanistically, the hypoxic microenvironment prevailing in the MM bone marrow niche stimulated the expression of steroid receptor coactivator 3 (SRC-3) in γδ T cells, which in turn interacted with the transcriptional factor RORγt, promoting Il17 transcription. Pharmacologic inhibition of SRC-3 utilizing SI-2 effectively suppressed Il17A expression in γδ T cells, leading to alleviation of MM progression in the murine models and enhancing the anti-multiple myeloma efficacy of bortezomib. Our results illuminated the bone marrow microenvironment's involvement in provoking γδ T-cell dysfunction throughout MM progression and suggest SRC-3 inhibition as a promising strategy to enhance the effectiveness of immunotherapies targeting γδ T cells.

A novel nomogram and risk stratification system predicting the cancer-specific survival of patients with gastric neuroendocrine carcinoma: a study based on SEER database and external validation.

BACKGROUND: Gastric neuroendocrine carcinoma (GNEC) is a rare histology of gastric cancer. The retrospective study was designed to construct and validate a nomogram for predicting the cancer-specific survival (CSS) of postoperative GNEC patients. METHODS: Data for 28 patients from the Hangzhou TCM Hospital were identified as the external validation cohort. A total of 1493 patients were included in the SEER database and randomly assigned to the training group (1045 patients) and internal validation group (448 patients). The nomogram was constructed using the findings of univariate and multivariate Cox regression studies. The model was evaluated by consistency index (C-index), calibration plots, and clinical net benefit. Finally, the effect between the nomogram and AJCC staging system was compared by net reclassification index (NRI) and integrated discrimination improvement (IDI). RESULTS: Age, gender, grade, T stage, N stage, metastasis, primary site, tumor size, RNE, and chemotherapy were incorporated in the nomogram. The C-indexes were 0.792 and 0.782 in the training and internal verification sets. The 1-, 3-, and 5-year CSS predicted by the nomogram and actual measurements had good agreement in calibration plots. The 1-, 3-, and 5-year NRI were 0.21, 0.29, and 0.37, respectively. The 1-, 3-, and 5-year IDI values were 0.10, 0.12, and 0.13 (P < 0.001), respectively. In 1-, 3-, and 5-year CSS prediction using DCA curves, the nomogram outperformed the AJCC staging system. The nomogram performed well in both the internal and external validation cohorts. CONCLUSION: We developed and validated a nomogram to predict 1-, 3-, and 5-year CSS for GNEC patients after surgical resection. This well-performing model could help doctors enhance the treatment plan.

De-escalating chemotherapy for stage I-II gastric neuroendocrine carcinoma? A real-world competing risk analysis.

BACKGROUND: The role of adjuvant chemotherapy in gastric neuroendocrine neoplasms (GNEC) has not been well clarified yet. The study was designed to investigate the potential effect of adjuvant chemotherapy in stage I-II GNEC patients and construct a predictive nomogram. METHOD: Stage I-II GNEC patients were included in the Surveillance, Epidemiology, and End Results (SEER) database and divided into chemotherapy and no-chemotherapy groups. We used Kaplan-Meier survival analyses, propensity score matching (PSM), and competing risk analyses. The predictive nomogram was then built and validated. RESULTS: Four hundred four patients with stage I-II GNEC were enrolled from the SEER database while 28 patients from Hangzhou TCM Hospital were identified as the external validation cohort. After PSM, similar 5-year cancer-specific survival was observed in two groups. The outcomes of competing risk analysis indicated a similar 5-year cumulative incidence of cancer-specific death (CSD) between the two cohorts (35.4% vs. 31.4%, p = 0.731). And there was no significant relation between chemotherapy and CSD in the multivariate competing risks regression analysis (HR, 0.79; 95% CI, 0.48-1.31; p = 0.36). Furthermore, based on the variables from the multivariate analysis, a competing event nomogram was created to assess the 1-, 3-, and 5-year risks of CSD. The 1-, 3-, and 5-year area under the receiver operating characteristic curve (AUC) values were 0.770, 0.759, and 0.671 in the training cohort, 0.809, 0.782, and 0.735 in the internal validation cohort, 0.786, 0.856, and 0.770 in the external validation cohort. Furthermore, calibration curves revealed that the expected and actual probabilities of CSD were relatively consistent. CONCLUSION: Stage I-II GNEC patients could not benefit from adjuvant chemotherapy after surgery. De-escalation of chemotherapy should be considered for stage I-II GNEC patients. The proposed nomogram exhibited excellent prediction ability.

A Novel Nomogram for Identifying Candidates for Adjuvant Chemotherapy in Patients With Stage IB Non-small Cell Lung Cancer.

BACKGROUND: This study aimed to develop a novel predictive nomogram to identify specific stage IB non-small cell lung cancer (NSCLC) populations who could benefit from adjuvant chemotherapy (ACT). METHOD: Stage IB NSCLC patients were included in the Surveillance, Epidemiology, and End Results (SEER) database and divided into the ACT and non-ACT groups. Then the methods of Kaplan-Meier analysis, propensity score matching (PSM), Least absolute shrink and selection operator (LASSO) regression, and multivariate logistic regression analyses were implemented. Finally, the predictive nomogram was constructed and validated. RESULTS: 9055 stage IB NSCLC patients were enrolled from the SEER database while 47 patients from Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University were identified as the external validation cohort. Of these patients, 1334 cases underwent ACT while the other 7721 patients didn't receive ACT. After PSM, the patients in the ACT group presented longer median overall survival (100 vs 82 months, P < .001). Among the ACT group, 482 (49.6%) patients achieving more prolonged overall survival than 82 months were regarded as the beneficiary population. Then the LASSO regression and multivariate logistic regression analyses were implemented. Finally, 8 predictors were selected for model construction, including age, gender, marital status, laterality, pathology, tumor size, regional nodes examined, and tumor size. The predictive nomogram demonstrated good discrimination in the training cohort (AUC = .781), internal validation cohort (AUC = .772), and external validation cohort (AUC = .851). And calibration curves indicated ideal consistency between the predicted and observed probabilities. Decision curve analysis presented a clinically useful model. CONCLUSION: The practical nomogram could guide treatment decision-making and select optimal ACT candidates among stage IB NSCLC patients.

Identification of cuproptosis-related lncRNAs to predict prognosis and immune infiltration characteristics in alimentary tract malignancies.

BACKGROUND: Alimentary tract malignancies (ATM) caused nearly one-third of all tumor-related death. Cuproptosis is a newly identified cell death pattern. The role of cuproptosis-associated lncRNAs in ATM is unknown. METHOD: Data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were used to identify prognostic lncRNAs by Cox regression and LASSO. Then a predictive nomogram was constructed based on seven prognostic lncRNAs. In addition, the prognostic potential of the seven-lncRNA signature was verified via survival analysis, the receiver operating characteristic (ROC) curve, calibration curve, and clinicopathologic characteristics correlation analysis. Furthermore, we explored the associations between the signature risk score and immune landscape, and somatic gene mutation. RESULTS: We identified 1211 cuproptosis-related lncRNAs and seven survival-related lncRNAs. Patients were categorized into high-risk and low-risk groups with significantly different prognoses. ROC and calibration curve confirmed the good prediction capability of the risk model and nomogram. Somatic mutations between the two groups were compared. We also found that patients in the two groups responded differently to immune checkpoint inhibitors and immunotherapy. CONCLUSION: The proposed novel seven lncRNAs nomogram could predict prognosis and guide treatment of ATM. Further research was required to validate the nomogram.

A novel nomogram for identifying candidates for adjuvant chemotherapy in patients with stage IB gastric adenocarcinoma.

BACKGROUND: The purpose of this research was to construct a novel predictive nomogram to identify specific stage IB gastric adenocarcinoma (GAC) populations who could benefit from postoperative adjuvant chemotherapy (ACT). METHOD: Between 2004 and 2015, 1889 stage IB GAC patients were extracted from the Surveillance, Epidemiology, and End Results (SEER) program database. Then Kaplan-Meier survival analysis, univariate and multivariable Cox analyses, and univariate and multivariable logistic analyses were implemented. Finally, the predictive nomograms were constructed. The methods of area under the curve (AUC), calibration curve, and decision curve analysis (DCA) were used to validate the clinical effectiveness of the models. RESULTS: Of these patients, 708 cases underwent ACT, while the other 1181 patients didn't receive ACT. After PSM, the patients in the ACT group presented a longer median overall survival (133 vs. 85 months, p = 0.0087). Among the ACT group, 194 (36.0%) patients achieving more prolonged overall survival than 85 months were regarded as the beneficiary population. Then the logistic regression analyses were performed, and age, gender, marital status, primary site, tumor size, and regional nodes examined were included as predicting factors to construct the nomogram. The AUC value was 0.725 in the training cohort and 0.739 in the validation cohort, which demonstrated good discrimination. And calibration curves indicated ideal consistency between the predicted and observed probabilities. Decision curve analysis presented a clinically useful model. Furthermore, the prognostic nomogram predicting 1-, 3-, and 5-year cancer-specific survival presented good predictive ability. CONCLUSION: The benefit nomogram could guide clinicians in decision-making and selecting optimal candidates for ACT among stage IB GAC patients. And the prognostic nomogram presented great prediction ability for these patients.

Application of Intraoperative Fluorescence Imaging with Indocyanine Green in the Difficult Gallbladder: A Comparative Study between Indocyanine Green-Guided Fluorescence Cholangiography and Conventional Surgery.

Background: In the difficult gallbladder, the rate of bile duct injury (BDI) remains high. To lessen iatrogenic biliary injury, we attempted to utilize indocyanine green (ICG)-guided fluorescence cholangiography during surgery to illuminate the extrahepatic biliary tract. Materials and Methods: According to admission criteria, 38 patients were diagnosed with difficult gallbladder and underwent percutaneous transhepatic gallbladder drainage (PTGBD). Consecutive patients who underwent ICG-assisted laparoscopic biliary surgery (n = 18, ICG group) or conventional laparoscopic biliary surgery (n = 20, white light [WL group) were enrolled in this study. ICG group received ICG fluorescent cholangiography via PTGBD tube during operation; 16 cases of laparoscopic cholecystectomy (LC) and 2 cases of LC plus laparoscopic common bile duct exploration (LC+LCBDE) were performed by fluorescent laparoscopy. In the WL group, 16 cases of LC, 1 case of laparoscopic subtotal cholecystectomy (LSC), and 3 cases of LC+LCBDE were performed under white light without ICG. Result: The biliary system was successfully established in the ICG group. Compared with the WL group, the anatomy of the Calot's triangle with severe abdominal adhesion or local inflammatory edema was more clearly displayed by fluorescence. Laparoscopic surgery was completed in both groups without conversion to laparotomy. There were no significant differences in surgery-related complications (P = .232) and postoperative hospital stay (P = .074) between the two groups. However, compared with the WL group, the ICG group had less intraoperative blood loss (P = .002) and shorter operation duration (P = .006). Conclusion: ICG fluorescence cholangiography has good clinical application value in the difficult gallbladder, which can avoid iatrogenic BDI, reduce surgery-related complications and intraoperative blood loss, and shorten the duration of surgery.

Centimetre-scale single crystal α-MoO3: oxygen assisted self-standing growth and low-energy consumption synaptic devices.

High-density storage and neuromorphic devices based on 2D materials are hindered by large-scale growth. Moreover, the lack of a mature mechanism makes it difficult to obtain high-quality single crystals in large-scale 2D materials. In this work, we prepared a centimeter-scale single crystal α-MoO3via an oxygen assisted substrate-free self-standing growth method and mechanism and constructed high-performance synaptic devices based on the centimeter-scale α-MoO3. The oxygen assisted growth mechanism of α-MoO3 was developed from the periodic bond chain theory. The large-scale α-MoO3 is up to 2 cm and exhibits high homogeneity and single crystalline characteristic. Furthermore, with an optimized oxygen partial pressure (18%), the centimeter-scale α-MoO3 makes the as-prepared memristor achieve continuous conductance modulation. Moreover, the trap-controlled electron conducting mechanism of the memristor was demonstrated through I-V curve fitting analysis at various temperatures, in which the high resistance state section demonstrates space-charge-limited conduction (SCLC) mode. Moreover, the as-prepared α-MoO3 memristors exhibit low-energy consumption and well emulate the essential synaptic behaviors including excitatory/inhibitory postsynaptic current, paired-pulse facilitation and long-term plasticity.

Targeting ARHGEF12 promotes neuroblastoma differentiation, MYCN degradation, and reduces tumorigenicity.

PURPOSE: Neuroblastoma arises from developmental block of embryonic neural crest cells and is one of the most common and deadly pediatric tumors. However, the mechanism underlying this block is still unclear. Here, we show that targeting Rho guanine nucleotide exchange factor 12 (ARHGEF12, also named LARG) promotes MYCN degradation and neuroblastoma differentiation, leading to reduced neuroblastoma malignancy. METHODS: The neuroblastoma TARGET dataset was downloaded to assess ARHGEF12 expression. Cell differentiation, proliferation, colony formation and cell migration analyses were performed to investigate the effects of ARHGEF12 knockdown on neuroblastoma cells. Western blotting and immunohistochemistry were employed to determine protein expression. Animal xenograft models were used to investigate antitumor effects after ARHGEF12 knockdown or treatment with the ARHGEF12 inhibitor Y16 in vivo. RESULTS: We found that the expression level of ARHGEF12 was higher in neuroblastoma than in better-differentiated ganglioneuroblastoma. Knockdown of ARHGEF12 promoted neuroblastoma differentiation, decreased stemness-related gene expression, and increased differentiation-related gene expression. ARHGEF12 knockdown reduced tumor growth, and the resulting tumors showed bigger tumor cells compared to those in control neuroblastoma xenografts. In addition, it was found that ARHGEF12 knockdown promoted MYCN ubiquitination and degradation in MYCN-amplified tumors through RhoA/ROCK/GSK3ß signaling. Targeting ARHGEF12 with the small molecular inhibitor Y16 induced cell differentiation and attenuated neuroblastoma tumorigenicity. CONCLUSION: Our findings provide new insight into the mechanism by which ARHGEF12 regulates neuroblastoma tumorigenicity and suggest a translatable therapeutic approach by targeting ARHGEF12 with a small molecular inhibitor.

WTAP Mediated the N6-methyladenosine Modification of PDK4 to Regulate the Malignant Behaviors of Colorectal Cancer Cells In Vitro and In Vivo.

BACKGROUND: The role of WT1-associated protein (WTAP) in mediating the N6-methyladenosine (m6A) modification of pyruvate dehydrogenase kinase 4 (PDK4) in colorectal cancer (CRC) has been previously reported. OBJECTIVE: This research manages to unveil the function and mechanism of WTAP mediating the m6A modification in CRC. METHODS: Expressions of PDK4 and WTAP in CRC were assessed by bioinformatics analysis and verified by Western blot. After the transfection with short hairpin RNAs (shRNAs) for WTAP (shWTAP) and PDK4 (shPDK4) to manipulate the expressions of PDK4 and WTAP, the viability, proliferation, migration, invasion, and levels of m6A, PDK4 and WTAP in CRC cells were determined by cell counting kit-8 (CCK-8), colony formation, transwell, Western blot, or M6A-RNA immunoprecipitation (MeRIP)-qPCR assays. M6A binding sites in PDK4 were additionally predicted through bioinformatics analysis, and the interaction of PDK4 and WTAP was confirmed using an RNA pull-down assay. Tumor volume and weight in the constructed xenograft-tumor mouse model were recorded. RESULTS: PDK4 expression was low, yet WTAP and m6A expressions were high in CRC cells. WTAP bound with the m6A binding sites in PDK4. PDK4 silencing facilitated the viability, proliferation, migration and invasion, inhibited the expression of PDK4 in CRC cells, and accelerated the growth of xenografts in vivo. However, the depletion of WTAP4 exerted the opposite effects and further offset the impact of PDK4 silencing. CONCLUSION: WTAP mediates the m6A modification of PDK4 to regulate the malignant behaviors of CRC cells in vitro and in vivo.

Hypoxia induces chemoresistance to proteasome inhibitors through orchestrating deSUMOylation and ubiquitination of SRC-3 in multiple myeloma.

The bone marrow microenvironment in multiple myeloma (MM) is hypoxic and provides multi-advantages for the initiation of chemoresistance, but the underlying mechanisms and key regulators are still indistinct. In the current study, we found that hypoxia stimulus easily induced chemoresistance to proteasome inhibitors (PIs), and the steroid receptor coactivator 3 (SRC-3) expression was remarkably augmented at posttranslational level. Protein interactome analysis identified SENP1 as a key modifier of SRC-3 stability, as SENP1-mediated deSUMOylation attenuated the K11-linked polyubiquitination of SRC-3. SENP1 depletion in the SENP1fl/flCD19Cre/+ B cells showed impaired SRC3 stability, and knockdown of SENP1 in MM cells by CRISPR/cas9 sgRNA accelerated the degradation of SRC-3 and remarkably overcame the resistance to PIs. In the Vk*Myc and 5TGM1 mouse models as well as patient-derived xenograft (PDX) of myeloma, SENP1 inhibitor Momordin Ιc (Mc) increased the sensitivity to PIs in MM cells. Importantly, SENP1 level was positively correlated with SRC-3 level in the tissues from refractory/relapsed MM, as well as in xenograft tissues from mice treated with bortezomib and Mc. Taken together, our findings suggest that hypoxia-induced SENP1 is a crucial regulator of chemoresistance to PIs, and shed light on developing therapeutic strategies to overcome chemoresistance by using small molecules targeting SENP1 or SRC-3.