c-Myc Activity Research Articles

Rocaglamide reprograms glucose metabolism in erythroleukemic cells via c-MYC transcriptional regulation of TXNIP and HK2

Ethnopharmacological relevanceThe theory of traditional Chinese medicine (TCM) views leukemia as an imbalance between cell growth and death mainly caused by blood stasis. Medicinal plants Aglaia Lour. (family Meliaceae) are traditionally used as folk medicine in China. It possesses the effects of removing blood stasis and swelling for treatment of cancer. Rocaglamide (RocA) is the main active phytochemical component of the genus Aglaia Lour. Possessing highly anti-leukemia properties. However, the molecular mechanisms by which RocA exerts its anti-growth effect on erythroleukemia cells are largely unknown. Aim of the studyThis study aimed to explore the underlying mechanism and glucose metabolism regulation effects of RocA responsible for its anti-erythroleukemia activity. Materials and methodsHuman erythroleukemic cells were tested for glucose metabolism and treated with glucose deprivation and RocA. MTT assay, cell cycle and apoptosis were used to elucidate growth inhibition. Glucose uptake, glucose consumption and lactate production were evaluated for identification of glucose metabolism. Luciferase assay and ChIP were used to examine the transcriptional activity of c-MYC on the conserved E-boxes binding of the TXNIP (thioredoxin-interacting protein) and HK2 (hexokinase 2) genes. siRNA, shRNA and exogenous transfection were employed to elucidate the effects of TXNIP and HK2 on glucose metabolism. ResultsWe find that glucose deprivation results in growth inhibition, cell cycle arrest and extensive apoptosis in erythroleukemic cells accompanied by downregulation of c-MYC and HK2, responsible for glucose metabolism. The similar results emerged in RocA treated erythroleukemic cells in presence of glucose. RocA is shown to decrease glucose uptake, glucose consumption and lactate production. Mechanistically, RocA dramatically increases TXNIP expression through interference with c-MYC binding to the promoter of the TXNIP gene. RocA also represses c-MYC transcriptional recognition of conserved E-boxes in the HK2 first intron, resulting in HK2 loss. These results implicate c-MYC as an important regulator of TXNIP and HK2 after RocA treatment. TXNIP overexpression or knockdown of HK2 suppresses the proliferation of erythroleukemic cells. Ectopic TXNIP expression restricts glucose uptake and HK2 suppression decreases glucose utilization. Further, our data suggests that loss of HK2 weakens the RocA-driven inhibition effects. We propose repression of c-MYC or the binding by RocA upregulates TXNIP and downregulates HK2, possibly contributes to growth inhibition in human erythroleukemic cells. ConclusionsThis study uncovers molecular mechanism of RocA against leukemic cells proliferation, linking the anti-erythroleukemia properties of RocA to glucose metabolism.

Repurposing colforsin daropate to treat MYC-driven high-grade serous ovarian carcinomas.

High-grade serous ovarian cancer (HGSOC) is one of the deadliest cancers for women, with a low survival rate, no early detection biomarkers, a high rate of recurrence, and few therapeutic options. Forskolin, an activator of cyclic AMP signaling, has several anticancer activities, including against HGSOC, but has limited use in vivo. Its water-soluble derivative, colforsin daropate, has the same mechanism of action as forskolin and is used to treat acute heart failure. Here, we investigated the potential of colforsin daropate as a treatment for HGSOC. We found that colforsin daropate induced cell cycle arrest and apoptosis in cultured HGSOC cells and spheroids but had negligible cytotoxicity in immortalized, nontumorigenic fallopian tube secretory cells and ovarian surface epithelial cells. Colforsin daropate also prevented HGSOC cells from invading ovarian surface epithelial cell layers in culture. In vivo, colforsin daropate reduced tumor growth, synergized with cisplatin (a standard chemotherapy in ovarian cancer care), and improved host survival in subcutaneous and intraperitoneal xenograft models. These antitumor effects of colforsin daropate were mediated in part by its reduction in the abundance and transcriptional activity of the oncoprotein c-MYC, which is often increased in HGSOC. Our findings demonstrate that colforsin daropate may be a promising therapeutic that could be combined with conventional therapies to treat HGSOC.

Conditional Activation of c-MYC in Distinct Catecholaminergic Cells Drives Development of Neuroblastoma or Somatostatinoma.

c-MYC is an important driver of high-risk neuroblastoma. A lack of c-MYC-driven genetically engineered mouse models (GEMM) has hampered the ability to better understand mechanisms of neuroblastoma oncogenesis and to develop effective therapies. Here, we showed that conditional c-MYC induction via Cre recombinase driven by a tyrosine hydroxylase (Th) promoter led to a preponderance of PDX1+ somatostatinoma, a type of pancreatic neuroendocrine tumor (PNET). However, c-MYC activation via an improved Cre recombinase driven by a dopamine β-hydroxylase (Dbh) promoter resulted in neuroblastoma development. The c-MYC murine neuroblastoma tumors recapitulated the pathologic and genetic features of human neuroblastoma and responded to anti-GD2 immunotherapy and DFMO, an FDA-approved inhibitor targeting the MYC transcriptional target ODC1. Thus, c-MYC overexpression results in different but related tumor types depending on the targeted cell. The GEMMs represent valuable tools for testing immunotherapies and targeted therapies for these diseases.

Effect of gedunin on cell proliferation and apoptosis in skin melanoma cells A431 via the PI3K/JNK signaling pathway.

Melanoma is an aggressive skin malignancy with rapid metastasis and high morbidity. Gedunin (GN) is a tetranortriterpenoid belonging to the Meliaceae family, described for its anticancer, antiproliferative and apoptotic properties. In the present study, we investigated the effect of GN on A431 melanoma cell proliferation and apoptosis. The inflammatory proteins (tumor necrosis factor alpha (TNF-α), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), cycloxygenase 2 (COX-2), inducible nitric oxide synthase (iNOS), and interleukin 6 (IL-6)) apoptosis-related proteins, such as Bax, Bcl-2 and caspase-3, and alterations in the PI3K/JNK and p38 pathways in A431 cells after GN treatment were examined. The cytotoxicity assay and cell apoptosis of GN activity on A431 cells were assessed using MTT assay, acridine orange/ethidium bromide (AO/EB), DAPI (4',6-diamidino-2-phenylindole), propidium iodide (PI), enzyme-linked immunosorbent assay (ELISA), reverse transcription polymerase chain reaction (RT-PCR) and western blot analyses. The findings demonstrated that GN (10 and 15 μM/mL) inhibits the growth of melanoma cells, triggers apoptosis by enhancing Bax and caspase, and reduces Bcl-2, cyclin-D1, c-myc, and survivin in a concentration-reliant manner. Additionally, GN attenuated the protein expression of inflammatory proteins (TNF-α, NF-κB, COX-2, iNOS, and IL-6) and the cell proliferative PI3K/JNK/p38 signaling pathway. Due to the imbalance in the Bax/Bcl-2 ratio, apoptosis is promoted, and the caspase cascade and Cyt-c are activated. This led us to conclude that GN treatment inhibited Bcl-2, cyclin-D1, c-myc, and survivin activity through the TNF-α/NF-κB and PI3K/JNK/p38 signaling pathways, further preventing the proliferation and stimulation of apoptosis, which contributes to growth arrest in melanoma cells. Gedunin has been shown to promote melanoma cell death in vitro, suggesting that it could be used as a future treatment for malignant melanoma. Our findings suggested that GN might be applied as a preventative measure in the management of skin melanoma cells.

Anti-Obesity Effects of Adzuki Bean Saponins in Improving Lipid Metabolism Through Reducing Oxidative Stress and Alleviating Mitochondrial Abnormality by Activating the PI3K/Akt/GSK3β/β-Catenin Signaling Pathway.

Obesity is a chronic and complex disease defined by the excessive deposition of fat and is highly associated with oxidative stress. Adzuki bean saponins (ABS) showed anti-obesity activity in our previous in vivo study; however, the active saponins of adzuki beans and potential mechanisms are still unclear. This research aims to elucidate the anti-obesity effects of ABS in improving lipid metabolism and oxidative stress, exploring the effective ingredients and potential molecular mechanisms through UHPLC-QE-MS analysis, network pharmacology, bioinformatics, and in vitro experiments both in the 3T3-L1 cell line and HepG2 cell line. The results indicate that ABS can improve intracellular lipid accumulation, adipogenesis, oxidative stress, and mitochondrial damage caused by lipid accumulation including ROS generation, abnormal mitochondrial membrane potential, and ATP disorder. Fifteen saponin components were identified with the UHPLC-QE-MS analysis. The network pharmacology and bioinformatics analyses indicated that the PI3K/Akt signaling pathway is associated with the bioactive effect of ABS. Through Western blotting and immunofluorescence analysis, the anti-obesity effect of ABS is achieved through regulation of the PI3K/Akt/GSK3β/β-catenin signaling pathway and activation of downstream transcription factor c-Myc in the lipid accumulation cell model, and regulation of β-catenin signaling and inhibition of downstream transcription factor C/EBPα in the adipocyte cell model. These results illustrate the biological activity of ABS in improving fat metabolism and oxidative stress by restoring mitochondrial function through β-catenin signaling, the PI3K/Akt/GSK3β/β-catenin signaling pathway, laying the foundation for its further development.

Mechanism of Alzheimer type II astrocyte development in hepatic encephalopathy

Type C hepatic encephalopathy (Type C HE) is a major and complex neurological condition that occurs following chronic liver failure. The molecular basis of Type C HE remains elusive. Type C HE is characterized by mental confusion, cognitive and motor disturbances. The presence of Alzheimer type II astrocytes (AT2A) is the key histopathological finding observed in Type C HE. However, nothing is currently known regarding AT2A development and its involvement in cognitive, and motor deficits in Type C HE. We, therefore, examined in rats the mechanisms by which liver failure contributes to the progression of AT2A, and its role in the development of cognitive and motor deficits in thioacetamide (TAA) model of Type C HE. We and others earlier reported increased oxidative/nitrosative stress (ONS), JNK1/2, and cMyc activation in ammonia-treated astrocyte cultures, as well as in brains from chronic liver failure. We now found increased levels of astrocytic glia maturation factor (GMF, a factor strongly implicated in neuroinflammation), as well as various inflammatory factors (IL-1β, TNF-α, IL-6, MMP-3, COX2, CXCL1, and PGE2), and reduced levels of GFAP and increased levels of aggregated nuclear protein Lamin A/C in rat brain cortex post-chronic liver failure. We also found increased levels of GMF and inflammatory factors (MMP-3, COX2, CXCL1, and PGE2) in astrocytes post-ammonia treatment in vitro. Additionally, pharmacological inhibition of upstream signaling of GMF (ONS, JNK1/2, and cMyc) or GMF inhibitors W-7 and trifluoperazine significantly reduced the levels of inflammatory factors, the number of AT2A cells, as well as the cognitive and motor deficits in TAA-treated rats. Increased levels of GMF were also identified in human post-mortem brain sections. These findings strongly suggest that increased levels of astrocytic GMF due to elevated levels of ONS, JNK1/2, and cMyc and the subsequent inflammation contribute to the development of AT2A and the consequent cognitive, and motor deficits in chronic liver failure.

Role of SIRT1-mediated synaptic plasticity and neurogenesis: Sex-differences in antidepressant-like efficacy of catalpol

BackgroundCatalpol, an important compound found in Rehmannia glutinosa (a plant with high nutritional and antidepressant medicinal value), exhibits various biological activities and has the ability to penetrate the blood-brain barrier. Our recent studies revealed a gender difference in the antidepressant activity of Rehmannia glutinosa with females showing better responses than males. Catalpol is likely the key compound responsible for this gender-specific difference, which caters to current clinical observations that the severity and impact of depression are approximately two to three times higher in females than in males. However, the sex-specific mechanism of catalpol's antidepressant effects remains unclear. Purpose and MethodsOur recent molecular network predictions suggest that the gender-specific antidepressant properties of catalpol primarily involve the regulation of SIRT1-mediated synaptic plasticity and neurogenesis. Building on this, the present study used a well-established chronic unpredictable mild stress model of depression in mice to confirm the sex-specific antidepressant characteristics of catalpol over time and intensity. Furthermore, using SIRT1 inhibitors and activators, behavioral tests, hematoxylin & eosin, Nissl, and Golgi staining, western blotting, immunofluorescence, and real-time PCR, we evaluated the key indicators of depressive behavior, synaptic plasticity, and neurogenesis before and after SIRT1 intervention to comprehensively assess whether the sex-specific antidepressant mechanism of catalpol indeed involves SIRT1-mediated synaptic plasticity and neurogenesis. ResultsThe gender-dependent antidepressant effects of catalpol are characterized by a faster onset and stronger effects in females compared to males, with females showing stronger regulation of SIRT1-mediated synaptic plasticity and neurogenesis. Activation of SIRT1 preserved the gender differences in catalpol's effects on depressive behavior, hippocampal synaptic plasticity (including neuronal consolidation, neuronal density, dendritic spines, and PSD95 and SYP gene and protein expression), and neurogenesis (including enhancement of GAP43 and MAP2 expression, activation of c-myc, cyclinD1, Ngn2, and NeuroD1 mRNA levels, and upregulation of the Wnt3a/β-catenin/GSK-3β pathway), while inhibition of SIRT1 abolished these gender differences in the effects of catalpol. ConclusionsCatalpol exhibits higher antidepressant activity in female mice compared to male mice, and the mechanism underlying this gender difference in antidepressant effects may depend on catalpol's higher sensitivity in improving hippocampal SIRT1-mediated synaptic plasticity and neurogenesis in females. The novelty of this study lies in its first-time revelation of the gender-specific phenotypes, targets, and molecular mechanisms of the antidepressant effects of catalpol.

Nonylphenol displays immunotoxicity by triggering hemocyte extracellular traps in Manila clam via ROS burst, ERK pathway and glycolysis

Nonylphenol (NP), an endocrine disruptor, has been demonstrated to be a harmful environmental contaminant and toxic to organisms. In this study, to address concerns regarding the immunotoxicity of NP, we treated clam Ruditapes philippinarum hemocytes with NP in vitro and explored the underlying mechanisms of NP-induced extracellular traps (ETs). NP could induce the formation of hemocytes ETs in a dose-dependent manner. Transcriptomics analysis revealed changes of signaling pathway involved in immunity and energy metabolism in hemocytes after NP stimulation. In this process, both reactive oxygen species (ROS) and myeloperoxidase (MPO) were up-regulated. Moreover, mitogen-activated protein kinase (MAPK) signaling pathway was proved to be activated in the formation of NP-induced ETs, manifested as enhanced phosphorylation of extracellular signal-regulated kinase (ERK) but not p38 or c-Jun N-terminal kinase (JNK). In the presence of U0126, an ERK phosphorylation inhibitor, the NP-induced expression of NADPH oxidase enzyme (NOX) was significantly decreased, which further alleviated the ROS production and ultimately limited the release of ETs. NP exposure increased glucose uptake, along with enhanced activities of glycolysis-related enzymes such as hexokinase (HK) and pyruvate kinase (PK). After inhibiting glycolysis by the inhibitor 2-DG, the formation of NP-induced ETs was significantly suppressed. ERK could regulate mTOR signaling and the PI3K/AKT pathway, potentially directing ETs formation by orchestrating the glycolysis through the activation of key transcription factors c-Myc and HIF-1α. Collectively, the results preliminary confirm that the ERK-NOX-ROS axis and glycolysis are involved in NP-induced ETs formation, contributing to the cellular immunotoxicity in clam.

TSC/mTORC1 mediates mTORC2/AKT1 signaling in c-MYC-induced murine hepatocarcinogenesis via centromere protein M.

Activated mTORC2/AKT signaling plays a role in hepatocellular carcinoma (HCC). Research has shown that TSC/mTORC1 and FOXO1 are distinct downstream effectors of AKT signaling in liver regeneration and metabolism. However, the mechanisms by which these pathways mediate mTORC2/AKT activation in HCC are not yet fully understood. Amplification and activation of c-MYC are key molecular events in HCC. In this study, we explored the roles of tuberous sclerosis complex/mTORC1 (TSC/mTORC1) and FOXO1 as downstream effectors of mTORC2/AKT1 in c-MYC-induced hepatocarcinogenesis. Using various genetic approaches in mice, we found that manipulating the FOXO pathway had a minimal effect on c-MYC-induced HCC. In contrast, loss of mTORC2 inhibited c-MYC-induced HCC, an effect that was completely reversed by ablation of TSC2, which activated mTORC1. Additionally, we discovered that p70/RPS6 and 4EBP1/eIF4E acted downstream of mTORC1, regulating distinct molecular pathways. Notably, the 4EBP1/eIF4E cascade is crucial for cell proliferation and glycolysis in c-MYC-induced HCC. We also identified centromere protein M (CENPM) as a downstream target of the TSC2/mTORC1 pathway in c-MYC-driven hepatocarcinogenesis, and its ablation entirely inhibited c-MYC-dependent HCC formation. Our findings demonstrate that the TSC/mTORC1/CENPM pathway, rather than the FOXO cascade, is the primary signaling pathway regulating c-MYC-driven hepatocarcinogenesis. Targeting CENPM holds therapeutic potential for treating c-MYC-driven HCC.

Abstract C029: Surface localization and targeting of enolase-1 (ENO1) as a novel theranostic approach for docetaxel-resistant neuroendocrine prostate cancer

Abstract Prostate cancer (PCa) is American men's second most common cancer. This cancer exhibits the most significant racial disparities among all cancer types, with elevated incidence and mortality in men of African ancestry. Although taxane-based chemotherapy with docetaxel (DTX) and cabazitaxel is the last line of defense for metastatic Castration Resistant Prostate Cancer (mCRPC), it invariably fails due to the development of chemoresistance. The protein-specific membrane antigen (PSMA) is currently an effective target for the imaging and therapy of mCRPC. However, although PSMA radioligand therapy (PSMA-RLT) is a theranostic option for men with advanced PCa, about 30% have a limited response to this treatment, particularly those that lack PSMA. In addition, some reports indicate that PSMA is suppressed in neuroendocrine PCa (NEPC), making it an unreliable theranostic target for this aggressive subtype. The glycolytic enzyme Enolase (ENO) is a promising theranostic alternative due to its cell surface localization in many human tumors. We hypothesized that ENO1 is abundant on the surface of NEPC-like cell lines and can be targeted with small molecule inhibitors (SMIs) that could potentially be used as theranostic agents. Western blotting (WB) analysis revealed that DTX-sensitive PCa cell lines expressing NEPC markers express both ENO1 and ENO2. By contrast, DTX-resistant NEPC-like cells only express ENO1 and therefore have a metabolic vulnerability due to the loss of ENO2. Additionally, we observed by WB and confocal microscopy changes in the expression and localization of ENO1 in NEPC-like cell lines under different glucose concentrations. Our results showed that under high glucose conditions, found on metabolically active metastatic tumors, ENO1 is highly abundant on the cell surface, making it a promising candidate target for theranostics. However, standard glucose conditions resulted in ENO1 downregulation, most likely due to inhibition of the activity of the c-MYC oncogene and upregulation of MBP1, the small splice variant of ENO1 that blocks the transcriptional activity of c-MYC. We also evaluated the cytotoxicity of SMIs designed to target ENO1 in chemoresistant NEPC-like cell lines using MTT viability assays, clonogenic assays, and Hoffman Modulation microscopy imaging. We observed that these inhibitors can significantly impair, with IC50 values at low micromolar concentrations, the proliferation and clonogenicity of NEPC cell lines. These results support our long-term goal to identify an alternative theranostic option for patients with NEPC by establishing ENO1 as a novel theranostic target. Citation Format: Krystal R. Santiago Torres, Kristen Whitley, Alfonso Duran, Bhaskar Das, Carlos Casiano, Frankis Almaguel. Surface localization and targeting of enolase-1 (ENO1) as a novel theranostic approach for docetaxel-resistant neuroendocrine prostate cancer [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C029.

HSPA12A promotes c-Myc lactylation-mediated proliferation of tubular epithelial cells to facilitate renal functional recovery from kidney ischemia/reperfusion injury

Proliferation of renal tubular epithelial cells (TEC) is essential for restoring tubular integrity and thereby to support renal functional recovery from kidney ischemia/reperfusion (KI/R) injury. Activation of transcriptional factor c-Myc promotes TEC proliferation following KI/R; however, the mechanism regarding c-Myc activation in TEC is incompletely known. Heat shock protein A12A (HSPA12A) is an atypic member of HSP70 family. In this study, we found that KI/R decreased HSPA12A expression in mouse kidneys and TEC, while ablation of HSPA12A in mice impaired TEC proliferation and renal functional recovery following KI/R. Gain-of-functional studies demonstrated that HSPA12A promoted TEC proliferation upon hypoxia/reoxygenation (H/R) through directly interacting with c-Myc and enhancing its nuclear localization to upregulate expression of its target genes related to TEC proliferation. Notably, c-Myc was lactylated in TEC after H/R, and this lactylation was enhanced by HSPA12A overexpression. Importantly, inhibition of c-Myc lactylation attenuated the HSPA12A-induced increases of c-Myc nuclear localization, proliferation-related gene expression, and TEC proliferation. Further experiments revealed that HSPA12A promoted c-Myc lactylation via increasing the glycolysis-derived lactate generation in a Hif1α-dependent manner. The results unraveled a role of HSPA12A in promoting TEC proliferation and facilitating renal recovery following KI/R, and this role of HSPA12A was achieved through increasing lactylation-mediated c-Myc activation. Therefore, targeting HSPA12A in TEC might be a viable strategy to promote renal functional recovery from KI/R injury in patients.Graphical abstractHSPA12A facilitated renal functional recovery from kidney ischemia/reperfusion (KI/R) injury. This protective effect of HSPA12A was mediated through directly interacting with c-Myc as well as upregulating the Hif1α-mediated lactate generation, thereby increasing c-Myc lactylation and nuclear localization to drive expression of genes related to cell proliferation, and ultimately promoting TEC proliferation.

Bioinformatic prediction of miR-320a as a potential negative regulator of CDGSH iron-sulfur domain 2 (CISD2), involved in lung adenocarcinoma bone metastasis via MYC activation, and associated with tumor immune infiltration.

Ferroptosis, a form of regulated cell death associated with iron-dependent lipid peroxidation, plays a role in cancer progression. However, the specific mechanisms of ferroptosis in lung adenocarcinoma (LUAD) bone metastasis (BM) remain unclear. Using bioinformatics analysis, this study sought to identify the ferroptosis-associated genes involved in BM in LUAD, thus providing potential novel targets for the treatment of BM in LUAD. The RNA expression dataset GSE10799 was acquired from the Gene Expression Omnibus (GEO) database, and intersected with the ferroptosis dataset to identify ferroptosis-related differentially expressed genes (DEGs). The expression of candidate genes and their correlation with the prognosis of LUAD patients were validated in The Cancer Genome Atlas (TCGA) database. A protein gene interaction network was constructed using GeneMania and Retrieval of Interacting Genes/Proteins (STRING) databases. The association between the candidate genes and immune cells was assessed via TCGA and Tumor IMmune Estimation Resource (TIMER) databases. The potential mechanisms were elucidated by a gene set enrichment analysis (GSEA). The relevant microRNAs (miRNAs or miRs) that bind to the 3'untranslated region (3'UTR) end of candidate genes' mRNA was explored using the TargetScan database. The expression of these candidate miRNAs in LUAD was validated and the correlation between candidate miRNAs and candidate mRNAs was tested using the TCGA database. Finally, the clinical data of 40 LUAD patients were retrospectively analyzed to evaluate the clinical value of candidate gene expression for LUAD BM patients. In this research, 15 ferroptosis-related DEGs in LUAD BM were identified. TCGA database analysis indicated that patients with low levels of CDGSH iron-sulfur domain 2 (CISD2) in LUAD had better disease-specific survival (DSS), overall survival (OS), and a better progression-free interval (PFI) than those with high levels of CISD2. The TIMER database results show that the expression of CISD2 is correlated with the infiltration levels of various immune cells. The GSEA indicated that CISD2 might influence biological activity in LUAD by participating in cell-cycle regulation, mitochondrial translation, DNA damage repair, c-Myc (MYC) activation, and the P53 signaling pathway. Through the combined analysis of the TargetScan and TCGA databases, hsa-miR-320a was identified as the optimal upstream regulatory miRNA. The immunohistochemistry data indicated that the positive CISD2 expression rates and immunohistochemistry scores of the patients with BM were significantly higher than those of the patients without BM (P<0.05). The high expression of CISD2 is a significant risk factor for BM in LUAD. The downregulation of CISD2 expression may extend DSS, OS, and the PFI of LUAD patients. Thus, CISD2 could serve as a novel predictive biomarker for LUAD patients. Further, miR-320a might negatively regulate CISD2 and participate in LUAD BM by activating MYC. These data provide a potential perspective for developing anticancer therapies for LUAD-BM patients.

A common druggable signature of oncogenic c-Myc, mutant KRAS and mutant p53 reveals functional redundancy and competition among oncogenes in cancer

The major driver oncogenes MYC, mutant KRAS, and mutant TP53 often coexist and cooperate to promote human neoplasia, which results in anticancer therapeutic opportunities within their downstream molecular programs. However, little research has been conducted on whether redundancy and competition among oncogenes affect their programs and ability to drive neoplasia. By CRISPR‒Cas9-mediated downregulation we evaluated the downstream proteomics and transcriptomics programs of MYC, mutant KRAS, and mutant TP53 in a panel of cell lines with either one or three of these oncogenes activated, in cancers of the lung, colon and pancreas. Using RNAi screening of the commonly activated molecular programs, we found a signature of three proteins - RUVBL1, HSPA9, and XPO1, which could be efficiently targeted by novel drug combinations in the studied cancer types. Interestingly, the signature was controlled by the oncoproteins in a redundant or competitive manner rather than by cooperation. Each oncoprotein individually upregulated the target genes, while upon oncogene co-expression each target was controlled preferably by a dominant oncoprotein which reduced the influence of the others. This interplay was mediated by redundant routes of target gene activation - as in the case of mutant KRAS signaling to c-Jun/GLI2 transcription factors bypassing c-Myc activation, and by competition - as in the case of mutant p53 and c-Myc competing for binding to target promoters. The global transcriptomics data from the cell lines and patient samples indicate that the redundancy and competition of oncogenic programs are broad phenomena, that may constitute even a majority of the genes dependent on oncoproteins, as shown for mutant p53 in colon and lung cancer cell lines. Nevertheless, we demonstrated that redundant oncogene programs harbor targets for efficient anticancer drug combinations, bypassing the limitations for direct oncoprotein inhibition.

AFP-HSP90 mediated MYC/MET activation promotes tumor progression in hepatocellular carcinoma and gastric cancers

Alpha-fetoprotein (AFP) elevation is a well-known biomarker in various diseases, particularly in the diagnosis of hepatocellular carcinoma (HCC). Intracellular AFP has been previously implicated in promoting tumorigenesis. In this study, we discovered that AFP enhances the stability of oncoproteins c-MYC and c-MET, thereby facilitating the progression of liver and gastric tumors. Our findings suggest that AFP acts by stabilizing these oncoproteins, which are clients of heat shock protein 90 (HSP90), and prevents their degradation through ubiquitination. Intriguingly, we identified AFP as a novel co-chaperone of HSP90, demonstrating its ability to regulate the stabilization of HSP90 client proteins. Furthermore, our results indicate that inhibiting AFP or HSP90 enhances the cytotoxicity of chemotherapeutic agents in AFP-producing HCC and gastric cancer cells. These findings have significant implications for the development of therapeutic strategies targeting AFP-producing tumors, as the AFP-HSP90-mediated activation of c-MYC and c-MET provides new insights into potential treatment approaches. In summary, this study sheds light on the role of AFP in promoting tumor progression by stabilizing oncoproteins through its interaction with HSP90. The identification of this mechanism opens up new avenues for therapeutic interventions in AFP-producing tumors.

Prevention of supercritical carbon dioxide fluid extract from Chrysanthemum indicum Linnén on cutaneous squamous cell carcinomas progression following UV irradiation in mice.

Chrysanthemum indicum Linnén (C. indicum), a medicinal and food herb with various bioactive components, may be of beneficial use in cosmetics and the treatment of skin-related diseases. However, to date, few studies have been reported on its potential preventive and therapeutic effects on skin cancer. Therefore, the present study aimed to investigate the effect and potential mechanism of action of supercritical carbon dioxide extract from C. indicum (CISCFE) on UV-induced skin cancer in a mouse model. Kunming mice were allocated randomly to five treatment groups: Sham, model, low concentration CISCFE, high concentration CISCFE and positive control nicotinamide groups. The dorsal skin of mice was irradiated with UV light for 31 weeks. Histopathological changes, ELISA assays, immunohistochemical analysis and western blotting were performed to investigate the potential therapeutic effects of CISCFE. The results showed that CISCFE alleviated skin oxidative and inflammatory damage in a UV-induced mouse model of skin cancer. Moreover, CISCFE suppressed abnormal activation of proto-oncogene c-Myc and the overexpression of Ki-67 and VEGF, and increased expression of the anti-oncogene PTEN, thereby reducing abnormal proliferation of the epidermis and blood vessels. Additionally, CISCFE increased the protein expression levels of NAD-dependent protein deacetylase sirtuin-1 (SIRT1), Kelch-like ECH associated protein 1 (Keap1) and inhibited the expression of nuclear factor 2 erythroid 2-related factor 2 (Nrf2), phosphorylated (p)-p62 (Ser 349), p-p65 and acetyl-p65 proteins in a UV-induced skin cancer mouse model. In summary, CISCFE exhibited potent anti-skin cancer activity, which may be attributed its potential effects on the p62/Keap1-Nrf2 and SIRT1/NF-κB pathways.

The role of RRS1 in breast cancer cells metastasis and AEG-1/AKT/c-Myc signaling pathway.

Breast cancer is the most common malignant tumor in women. Recurrence, metastasis, and chemotherapy resistance are the main causes of death in breast cancer patients. The inhibition of breast cancer metastasis is of great significance for prolonging its survival. Ribosome biogenesis regulatory protein homolog (RRS1) is overexpressed in breast cancer tissues and is involved in regulating the carcinogenic process of breast cancer cells. However, the exact signaling pathway and molecular mechanism of RRS1 promoting breast cancer metastasis are not fully understood. Hence, the primary objective of our study is to investigate the correlation between RRS1 and breast cancer metastasis. Bioinformatic analysis was used to identify the expression levels and prognostic significance of RRS1 in breast cancer. Lenti-sh RRS1 lentivirus was constructed and employed to downregulate the RRS1 expression in MDA-MB-231 and BT549 cells, which had a high-level expression of RRS1. Subsequently, we assessed the impact of RRS1 downregulation on the proliferation, migration, and invasion of breast cancer cells using CCK-8, apoptosis, and cell cycle by flow cytometry, wound healing test, Transwell migration, and invasion experiments. Moreover, we utilized an in vivo imaging system to examine the metastatic potential of breast cancer cells after RRS1 knockdown. Picrate staining and hematoxylin-eosin staining were employed to evaluate the presence of metastatic lesions. To gain a deeper understanding of the molecular mechanism, we conducted co-immunoprecipitation and western blot. The significant overexpression of RRS1 in breast cancer indicates a worse prognosis, as determined through TCGA databases (p<0.01). Additionally, RRS1 exhibits upregulation in breast cancer (p<0.001), which is tightly linked to the occurrence of lymph node metastasis (p<0.001). Clinical breast cancer tissues and breast cancer cell lines also demonstrated a noteworthy upregulation of RRS1 (p<0.05). Loss-of-function experiment illustrated that the inhibiting of RRS1 expression reduced the rapid proliferation capacity of MDA-MB-231 and BT549 cells and hindered their migration and invasion capabilities (p<0.05). Importantly, the suppression of RRS1 significantly diminished lung metastasis in Balb/c nude mice that were injected with MDA-MB-231 cells (p<0.01). Mechanistically, RRS1 may interact with the AEG-1 to modulate the phosphorylation of AKT at T308 and S473, consequently impeding the activity of c-Myc (p<0.05). To conclude, RRS1 functions as a potential oncogene in breast cancer by leveraging the AEG-1/AKT/c-Myc signaling.

Mitochondrial diabetes in mice expressing a dominant-negative allele of nuclear respiratory factor-1 (Nrf1) in pancreatic β-cells

Genetic polymorphisms in nuclear respiratory factor-1 (Nrf1), a key transcriptional regulator of nuclear-encoded mitochondrial proteins, have been linked to diabetes. Homozygous deletion of Nrf1 is embryonic lethal in mice. Our goal was to generate mice with β-cell-specific reduction in NRF1 function to investigate the relationship between NRF1 and diabetes. We report the generation of mice expressing a dominant-negative allele of Nrf1 (DNNRF1) in pancreatic β-cells. Heterozygous transgenic mice had high fed blood glucose levels detected at 3 wks of age, which persisted through adulthood. Plasma insulin levels in DNNRF1 transgenic mice were reduced, while insulin sensitivity remained intact in young animals. Islet size was reduced with increased numbers of apoptotic cells, and insulin content in islets by immunohistochemistry was low. Glucose-stimulated insulin secretion in isolated islets was reduced in DNNRF1-mice, but partially rescued by KCl, suggesting that decreased mitochondrial function contributed to the insulin secretory defect. Electron micrographs demonstrated abnormal mitochondrial morphology in β-cells. Expression of NRF1 target genes Tfam, Tfb1m and Tfb2m, and islet cytochrome c oxidase and succinate dehydrogenase activities were reduced in DNNRF1-mice. Rescue of mitochondrial function with low level activation of transgenic c-Myc in β-cells was sufficient to restore β-cell mass and prevent diabetes. This study demonstrates that reduced NRF1 function can lead to loss of β-cell function and establishes a model to study the interplay between regulators of bi-genomic gene transcription in diabetes.

Novel gene therapy for drug-resistant melanoma: Synergistic combination of PTEN plasmid and BRD4 PROTAC-loaded lipid nanocarriers

Patients suffering from BRAF mutant melanoma have tumor recurrence within merely 7 months of treatment with a potent BRAF inhibitor (BRAFi) like vemurafenib (VEM). It has been proven that diverse molecular pathways driving BRAFi resistance converge to activation of c-Myc in melanoma. Therefore, we identified a novel combinatorial therapeutic strategy by targeting loss of PTEN tumor suppressor gene and upregulated BRD4 oncoprotein as Myc-dependent vulnerabilities of drug-resistant melanoma. Being promising therapeutic targets, we decided to concomitantly deliver PTEN plasmid and BRD4 targeted PROteolysis-TArgeting Chimera (ARV) to drug the “undruggable” c-Myc in BRAFi-resistant melanoma. Since PTEN plasmid and ARV are distinct in their physicochemical properties, we fabricated PTEN-plasmid loaded LNPs (PL-NANO) and ARV-825 loaded nanoliposomes (AL-NANO) to yield mean particle size of <100 nm and >99% encapsulation efficiency for each therapeutic payload. Combination of PL-NANO and AL-NANO displayed synergistic tumor growth inhibition and substantial apoptosis in in vitro 2D and 3D models. Importantly, simultaneous delivery of PL-NANO and AL-NANO achieved significant upregulation of PTEN expression levels and degradation of BRD4 protein to ultimately downregulate c-Myc levels in BRAFi-resistant melanoma cells. Altogether, lipid nanocarriers delivering this novel lethal cocktail stands as “one-of-a-kind” gene therapy to target “undruggable” c-Myc oncogene in BRAFi-resistant melanoma.

USP11 promotes prostate cancer progression by up-regulating AR and c-Myc activity

Androgen receptor (AR) is a main driver for castration-resistant prostate cancer (CRPC). c-Myc is an oncogene underlying prostate tumorigenesis. Here, we find that the deubiquitinase USP11 targets both AR and c-Myc in prostate cancer (PCa). USP11 expression was up-regulated in metastatic PCa and CRPC. USP11 knockdown (KD) significantly inhibited PCa cell growth. Our RNA-seq studies revealed AR and c-Myc as the top transcription factors altered after USP11 KD. ChIP-seq analysis showed that either USP11 KD or replacement of endogenous USP11 with a catalytic-inactive USP11 mutant significantly decreased chromatin binding by AR and c-Myc. We find that USP11 employs two mechanisms to up-regulate AR and c-Myc levels: namely, deubiquitination of AR and c-Myc proteins to increase their stability and deubiquitination of H2A-K119Ub, a repressive histone mark, on promoters of AR and c-Myc genes to increase their transcription. AR and c-Myc reexpression in USP11-KD PCa cells partly rescued cell growth defects. Thus, our studies reveal a tumor-promoting role for USP11 in aggressive PCa through upregulation of AR and c-Myc activities and support USP11 as a potential target against PCa.

PIM1 is a potential therapeutic target for the leukemogenic effects mediated by JAK/STAT pathway mutations in T-ALL/LBL

Precursor T-cell neoplasms (T-ALL/LBL) are aggressive hematological malignancies that arise from the malignant transformation of immature thymocytes. Despite the JAK/STAT pathway is recurrently altered in these neoplasms, there are not pharmacological inhibitors officially approved for the treatment of T-ALL/LBL patients that present oncogenic JAK/STAT pathway mutations. In the effort to identify potential therapeutic targets for those patients, we followed an alternative approach and focused on their transcriptional profile. We combined the analysis of molecular data from T-ALL/LBL patients with the generation of hematopoietic cellular models to reveal that JAK/STAT pathway mutations are associated with an aberrant transcriptional profile. Specifically, we demonstrate that JAK/STAT pathway mutations induce the overexpression of the PIM1 gene. Moreover, we show that the pan-PIM inhibitor, PIM447, significantly reduces the leukemogenesis, as well as the aberrant activation of c-MYC and mTOR pathways in cells expressing different JAK/STAT pathway mutations, becoming a potential therapeutic opportunity for a relevant subset of T-ALL/LBL patients.