Rac1 activates non-oxidative pentose phosphate pathway to induce chemoresistance of breast cancer

Resistance development to one chemotherapeutic reagent leads frequently to acquired tolerance to other compounds, limiting the therapeutic options for cancer treatment. Herein, we find that overexpression of Rac1 is associated with multi-drug resistance to the neoadjuvant chemotherapy (NAC). Mechanistically, Rac1 activates aldolase A and ERK signaling which up-regulates glycolysis and especially the non-oxidative pentose phosphate pathway (PPP). This leads to increased nucleotides metabolism which protects breast cancer cells from chemotherapeutic-induced DNA damage. To translate this finding, we develop endosomal pH-responsive nanoparticles (NPs) which deliver Rac1-targeting siRNA together with cisplatin and effectively reverses NAC-chemoresistance in PDXs from NAC-resistant breast cancer patients. Altogether, our findings demonstrate that targeting Rac1 is a potential strategy to overcome acquired chemoresistance in breast cancer.

Nanoparticles (NPs)-Meditated LncRNA AFAP1-AS1 Silencing to Block Wnt/β-Catenin Signaling Pathway for Synergistic Reversal of Radioresistance and Effective Cancer Radiotherapy

Resistance to radiotherapy is frequently encountered in clinic, leading to poor prognosis of cancer patients. Long noncoding RNAs (lncRNAs) play important roles in the development of radioresistance due to their functions in regulating the expression of target genes at both transcriptional and posttranscriptional levels. Exploring key lncRNAs and elucidating the mechanisms contributing to radioresistance are crucial for the development of effective strategies to reverse radioresistance, which however remains challenging. Here, actin filament-associated protein 1 antisense RNA1 (lncAFAP1-AS1) is identified as a key factor in inducing radioresistance of triple-negative breast cancer (TNBC) via activating the Wnt/β-catenin signaling pathway. Considering the generation of a high concentration of reduction agent glutathione (GSH) under radiation, a reduction-responsive nanoparticle (NP) platform is engineered for effective lncAFAP1-AS1 siRNA (siAFAP1-AS1) delivery. Systemic delivery of siAFAP1-AS1 with the reduction-responsive NPs can synergistically reverse radioresistance by silencing lncAFAP1-AS1 expression and scavenging intracellular GSH, leading to a dramatically enhanced radiotherapy effect in both xenograft and metastatic TNBC tumor models. The findings indicate that lncAFAP1-AS1 can be used to predict the outcome of TNBC radiotherapy and combination of systemic siAFAP1-AS1 delivery with radiotherapy can be applied for the treatment of recurrent TNBC patients.

Enhancer-Driven lncRNA BDNF-AS Induces Endocrine Resistance and Malignant Progression of Breast Cancer through the RNH1/TRIM21/mTOR Cascade

Epigenomic alterations can give rise to various tumor-promoting properties, including therapeutic resistance of cancer cells. Here, we identify an lncRNA, BDNF-AS, whose overexpression is specifically driven by a MEF2A-regulated enhancer in endocrine-resistant and triple-negative breast cancer (TNBC). High levels of BDNF-AS in breast cancer tissues not only feature endocrine resistance in hormone receptor (HR)-positive patients but also correlate with poor outcomes in both HR-positive and TNBC patients. Mechanistically, BDNF-AS acts as a molecular scaffold to promote RNH1 protein degradation via TRIM21-mediated ubiquitination of RNH1 at K225. Subsequently, BDNF-AS abolishes RNH1-regulated and RISC-mediated mTOR mRNA decay, therefore sustaining the activation of mTOR signaling. Importantly, mTOR inhibitor, but not PI3K inhibitor, could reverse tamoxifen resistance induced by the overexpression of BDNF-AS. These results point toward a master regulatory role of an enhancer-activated cascade of BDNF-AS/RNH1/TRIM21/mTOR in endocrine resistance and malignant progression of breast cancer.

The Use of Apatinib in Treating Nonsmall-Cell Lung Cancer: Case Report and Review of Literature

Apatinib is a novel tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor-2, which has been proved to be effective and safe in treating heavily pretreated patients with gastric cancer.The aim of the study was to explore the use of apatinib in treatment of nonsmall cell lung cancer and its side effects.We report 2 patients presented with advanced nonsmall-cell lung cancer, who received apatinib after failure in the first- or third-line chemotherapy. They are treated with apatinib in daily dose of 850 mg, 28 days per cycle.Favorable oncologic outcomes were achieved in the 2 cases after the treatment of apatinib. Patient I's progression-free-survival has increased to 4.6 months after palliative therapy of apatinib, whereas Patient II nearly 6 months. The common side effects of apatinib were hypertension and hand-foot syndrome; however, the toxicity of apatinib was controllable and tolerable.Apatinib may be an option for advanced nonsmall cell lung cancer after failure of chemotherapy or other targeted therapy. But that still warrants further investigation in the prospective study.

miR-668 enhances the radioresistance of human breast cancer cell by targeting IκBα

BACKGROUND

A large proportion of breast cancer patients are resistant to radiotherapy, which is a mainstay treatment for this malignancy, but the mechanisms of radioresistance remain unclear.

METHODS AND MATERIALS

To evaluate the role of miRNAs in radioresistance, we established two radioresistant breast cancer cell lines MCF-7R and T-47DR derived from parental MCF-7 and T-47D. Moreover, miRNA microarray, quantitative RT-PCR analysis, luciferase reporter assay and western blotting were used.

RESULTS

We found that miR-668 was most abundantly expressed in radioresistant cells MCF-7R and T-47DR. miR-668 knockdown reversed radioresistance of MCF-7R and T-47DR, miR-668 overexpression enhanced radioresistance of MCF-7 and T-47D cells. Mechanically, bioinformatics analysis combined with experimental analysis demonstrated IκBα, a tumor-suppressor as well as an NF-κB inhibitor, was a direct target of miR-668. Further, miR-668 overexpression inhibited IκBα expression, activated NF-κB, thus, increased radioresistance of MCF-7 and T-47D cells. Conversely, miR-668 knockdown restored IκBα expression, suppressed NF-κB, increased radiosensitivity of MCF-7R and T-47DR cells.

CONCLUSION

Our findings suggest miR-668 is involved in the radioresistance of breast cancer cells and miR-668-IκBα-NF-κB axis may be a novel candidate for developing rational therapeutic strategies for human breast cancer treatment.

LncRNA Uc003xsl.1-Mediated Activation of the NFκB/IL8 Axis Promotes Progression of Triple-Negative Breast Cancer

Aberrant activation of NFκB orchestrates a critical role in tumor carcinogenesis; however, the regulatory mechanisms underlying this activation are not fully understood. Here we report that a novel long noncoding RNA (lncRNA) Uc003xsl.1 is highly expressed in triple-negative breast cancer (TNBC) and correlates with poor outcomes in patients with TNBC. Uc003xsl.1 directly bound nuclear transcriptional factor NFκB-repressing factor (NKRF), subsequently preventing NKRF from binding to a specific negative regulatory element in the promoter of the NFκB-responsive gene IL8 and abolishing the negative regulation of NKRF on NFκB-mediated transcription of IL8. Activation of the NFκB/IL8 axis promoted the progression of TNBC. Trop2-based antibody-drug conjugates have been applied in clinical trials in TNBC. In this study, a Trop2-targeting, redox-responsive nanoparticle was developed to systematically deliver Uc003xsl.1 siRNA to TNBC cells in vivo, which reduced Uc003xsl.1 expression and suppressed TNBC tumor growth and metastasis. Therefore, targeting Uc003xsl.1 to suppress the NFκB/IL8 axis represents a promising therapeutic strategy for TNBC treatment.

SIGNIFICANCE

These findings identify an epigenetic-driven NFκB/IL8 cascade initiated by a lncRNA, whose aberrant activation contributes to tumor metastasis and poor survival in patients with triple-negative breast cancer.

Long Non-Coding RNA MNX1-AS1 Promotes Progression of Triple Negative Breast Cancer by Enhancing Phosphorylation of Stat3

Triple negative breast cancer (TNBC) accounts for less than a quarter of breast cancer but has the poorest survival outcome and is prone to relapse as well as metastasis due to its aggressiveness and lack of therapeutic target. Herein, we analyzed the TCGA datasets of lncRNA expressional profiles of breast cancer vs. normal tissue and TNBC vs. Non-TNBC subtypes and screened a long non-coding RNA (lncRNA) MNX1-AS1 overexpressing in TNBC. We found that MNX1-AS1 were upregulated in TNBC tumor tissues and correlated with poor survival outcome in TNBC patients. Silencing MNX1-AS1 reduced the aggressiveness of TNBC in vitro and in vivo. By using RNA pulldown assay followed by western blotting and RNA immunoprecipitation (RIP), we identified Stat3 was the MNX1-AS1 binding protein and MNX1-AS1 upregulated the phosphorylation of Stat3 by enhancing the interaction between p-JAK and Stat3. The present study suggested that targeting MNX1-AS1 may represent a promising therapeutic strategy to TNBC.

RYBP Inhibits Progression and Metastasis of Lung Cancer by Suppressing EGFR Signaling and Epithelial-Mesenchymal Transition

Lung cancer (LC) is a common lethal malignancy with rapid progression and metastasis, and Ring1 and YY1 binding protein (RYBP) has been shown to suppress cell growth in human cancers. This study aimed to investigate the role of RYBP in LC progression and metastasis. In this study, a total of 149 LC patients were recruited, and the clinical stage of their tumors, metastasis status, survival time, presence of epidermal growth factor receptor (EGFR) mutation, and RYBP expression levels were measured. RYBP silencing and overexpression were experimentally performed in LC cell lines and in nude mice, and the expressions of genes in EGFR-related signaling pathways and epithelial-mesenchymal transition (EMT) were detected. The results showed that RYBP was downregulated in LC compared with adjacent normal tissues, and low RYBP expression was associated with a more severe clinical stage, high mortality, high metastasis risk, and poor survival. Cell proliferation and xenograft growth were inhibited by RYBP overexpression, whereas proliferation and xenograft growth were accelerated by RYBP silencing. EGFR and phosphorylated-EGFR levels were upregulated when RYBP was silenced, whereas EGFR, p-EGFR, p-AKT, and p-ERK were downregulated when RYBP was overexpressed. Low RYBP expression was related to a high metastasis risk, and metastasized tumors showed low RYBP levels. Cell migration and invasion were promoted by silencing RYBP but were inhibited by overexpressed RYBP. In addition, the EMT marker vimentin showed diminished expression, and E-cadherin was promoted by the overexpression of RYBP. In conclusion, our data suggest that RYBP suppresses cell proliferation and LC progression by impeding the EGFR-ERK and EGFR-AKT signaling pathways and thereby inhibiting cell migration and invasion and LC metastasis through the suppression of EMT.

Deep learning magnetic resonance imaging predicts platinum sensitivity in patients with epithelial ovarian cancer

OBJECTIVE

The aim of the study is to develop and validate a deep learning model to predict the platinum sensitivity of patients with epithelial ovarian cancer (EOC) based on contrast-enhanced magnetic resonance imaging (MRI).

METHODS

In this retrospective study, 93 patients with EOC who received platinum-based chemotherapy (≥4 cycles) and debulking surgery at the Sun Yat-sen Memorial Hospital from January 2011 to January 2020 were enrolled and randomly assigned to the training and validation cohorts (2:1). Two different models were built based on either the primary tumor or whole volume of the abdomen as the volume of interest (VOI) within the same cohorts, and then a pre-trained convolutional neural network Med3D (Resnet 10 version) was transferred to automatically extract 1,024 features from two MRI sequences (CE-T1WI and T2WI) of each patient to predict platinum sensitivity. The performance of the two models was compared.

RESULTS

A total of 93 women (mean age, 50.5 years ± 10.5 [standard deviation]) were evaluated (62 in the training cohort and 31 in the validation cohort). The AUCs of the whole abdomen model were 0.97 and 0.98 for the training and validation cohorts, respectively, which was better than the primary tumor model (AUCs of 0.88 and 0.81 in the training and validation cohorts, respectively). In k-fold cross-validation and stratified analysis, the whole abdomen model maintained a stable performance, and the decision function value generated by the model was a prognostic indicator that successfully discriminates high- and low-risk recurrence patients.

CONCLUSION

The non-manually segmented whole-abdomen deep learning model based on MRI exhibited satisfactory predictive performance for platinum sensitivity and may assist gynecologists in making optimal treatment decisions.

Nigericin Boosts Anti-Tumor Immune Response via Inducing Pyroptosis in Triple-Negative Breast Cancer

Although immune checkpoint inhibitors improved the clinical outcomes of advanced triple negative breast cancer (TBNC) patients, the response rate remains relatively low. Nigericin is an antibiotic derived from Streptomyces hydrophobicus. We found that nigericin caused cell death in TNBC cell lines MDA-MB-231 and 4T1 by inducing concurrent pyroptosis and apoptosis. As nigericin facilitated cellular potassium efflux, we discovered that it caused mitochondrial dysfunction, leading to mitochondrial ROS production, as well as activation of Caspase-1/GSDMD-mediated pyroptosis and Caspase-3-mediated apoptosis in TNBC cells. Notably, nigericin-induced pyroptosis could amplify the anti-tumor immune response by enhancing the infiltration and anti-tumor effect of CD4+ and CD8+ T cells. Moreover, nigericin showed a synergistic therapeutic effect when combined with anti-PD-1 antibody in TNBC treatment. Our study reveals that nigericin may be a promising anti-tumor agent, especially in combination with immune checkpoint inhibitors for advanced TNBC treatment.

Nanoparticles (NPs)-mediated silencing of GSTP1 expression to reverse chemoresistance for effective breast cancer therapy

Chemotherapy remains the primary treatment modality for breast cancer (BCa) patients. However, chemoresistance commonly arises in clinical settings, contributing to poor prognosis. The development of chemoresistance is a dynamic and complex process involving the activation of oncogenes and inactivation of tumor suppressor genes. In this work, we utilized the RNA-sequencing (RNA-seq) technology to analyze the gene expression profiles of primary and recurrent tumor samples from BCa patients received the postoperative standard chemotherapy with doxorubicin (DOX), and identified glutathione S-transferase P1 (GSTP1) as a key factor in regulating chemoresistance. Molecular mechanistic studies revealed that high GSTP1 expression could not only impair the cytotoxicity of DOX by catalyzing the conjugation of reductive glutathione (GSH) with DOX, but also block the c-Jun NH2-terminal kinase (JNK) pathway to promote the proliferation via up-regulating anti-apoptotic B-cell lymphoma-2 (Bcl-2) expression. Given the severe side effects of DOX and the potential of RNA interference (RNAi) technology to silence target gene expression, we developed an endosomal pH-responsive nanoparticle (NP) platform for systemic co-delivery of DOX and GSTP1 siRNA (siGSTP1), and demonstrated its efficacy in reversing chemoresistance and suppressing the growth of DOX-resistant BCa tumors.

Circular RNA circ_ARHGEF28 inhibits MST1/2 dimerization to suppress Hippo pathway to induce cisplatin resistance in ovarian cancer

BACKGROUND

Cisplatin is integral to ovarian cancer treatment, yet resistance to this drug often results in adverse patient outcomes. The association of circular RNA (circRNA) with cisplatin resistance in ovarian cancer has been observed, but the mechanisms governing this relationship require further elucidation.

METHODS

High-throughput sequencing was utilized to profile circRNA expression in cisplatin-resistant ovarian cancer cells. Gain-and-loss-of-function experiments assessed the impact on cisplatin sensitivity, both in vitro and in vivo. Fluorescence in situ hybridization was conducted to determine the cellular distribution of circRNAs, and RNA pulldown and immunoprecipitation experiments were performed to identify associated binding proteins.

RESULTS

The study revealed that circ_ARHGEF28 is overexpressed in certain cisplatin-resistant ovarian cancer tissues and cell lines, and is associated with reduced progression-free survival in patients. It was observed that circ_ARHGEF28 contributes to cisplatin resistance in ovarian cancer models, both in vitro and in vivo. Importantly, circ_ARHGEF28 was found to interact directly with MST1/2, inhibiting the SARAH coiled-coil binding domains and consequently deactivating the Hippo pathway.

CONCLUSION

This investigation identifies circ_ARHGEF28 as a novel circRNA that contributes to cisplatin resistance in ovarian cancer by suppressing the Hippo pathway. Therapeutic strategies targeting circ_ARHGEF28 may offer a potential avenue to mitigate cisplatin resistance in ovarian cancer treatment.

Causal Relationships Between Gut Microbiota, Immune Cell and Pancreatic Cancer: A Two-Step, Two-Sample Mendelian Randomization Study

BACKGROUND

Gut microbiota (GM) is associated with both the occurrence and development of pancreatic cancer (PC), and immune cells potentially play a role in this process. This study sought to evaluate the causative effect of GM on PC and to ascertain possible immune cell mediators.

METHODS

The study primarily employed a two-step, two-sample Mendelian randomization (MR) analysis to explore the causal relationship between GM and PC within the European population, placing particular emphasis on the application of the inverse variance weighted (IVW) approach. Additionally, mediation analysis was conducted to explore the potential influence of immune cells as mediators.

RESULTS

The MR analysis revealed a significant association between Geminocystis and the risk of PC. Increased abundance of Geminocystis was positively associated with the risk of PC (odds ratio (OR): 2.580, 95% confidence interval (CI): 1.050 - 6.342). The validity of the outcomes was also verified by the sensitivity analysis. The mediation MR analysis showed that the B-cell absolute count served as a partial intermediary in the causal link between Geminocystis and the risk of PC, contributing to 15.321% of the mediating impact.

CONCLUSION

This MR study demonstrated that Geminocystis has a causal relationship with PC and potentially mediates B-cell absolute count in the TBNK panel.