EGF Relays Signals to COP1 and Facilitates FOXO4 Degradation to Promote Tumorigenesis

EGF-Upregulated lncRNA ESSENCE Promotes Colorectal Cancer Growth through Stabilizing CAD and Ferroptosis Defense

Epidermal growth factor receptor/mitogen-activated protein kinase (EGFR/MAPK) signaling is highly activated in various types of cancer. The long noncoding RNAs induced by this pathway and their roles in colorectal cancer (CRC) have not been fully elucidated. In this study, based on the profiling of long noncoding RNAs triggered by EGFR/MAPK signaling, we identified that ESSENCE (EGF [epidermal growth factor] Signal Sensing CAD's Effect; ENST00000415336), which is mediated by the transcription factor early growth response factor 1, functions as a potent oncogenic molecule that predicts poor prognosis in CRC. Mechanistically, ESSENCE directly interacts with carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase (CAD) and competitively attenuates CAD degradation mediated by its newly discovered E3 ligase KEAP1, thereby suppressing ferroptosis and promoting CRC progression. Importantly, combinational treatment of the mitogen-activated extracellular signal-regulated kinase inhibitor selumetinib and ferroptosis inducer sulfasalazine synergistically suppresses ESSENCE-high CRC in a patient-derived xenograft mouse model. Taken together, these findings demonstrate the crucial role of ESSENCE in mediating CRC progression by regulating CAD stabilization and suggest a therapeutic strategy of targeting the ESSENCE-CAD axis in CRC.

ACAA2 Protects Against Cardiac Dysfunction and Lipid Peroxidation in Renal Insufficiency with the Treatment of S-Nitroso-L-Cysteine

The key fatty acid β-oxidation protein acetyl-CoA acyltransferase 2 (ACAA2) plays a significant role in myocardial lipid peroxidation and cardiac dysfunction induced by renal insufficiency. However, the mechanisms of lipid metabolism related to renal insufficiency-associated cardiac dysfunction remain poorly understood, and current clinical treatments have been largely ineffective. Through analysis of the Gene Expression Omnibus (GEO) database, we identified that the cardiac functional changes caused by renal insufficiency were primarily centered around the fatty acid β-oxidation signaling pathway, where ACAA2 plays a pivotal role in fatty acid β-oxidation, the tricarboxylic acid cycle, and ketone body metabolism. In an adenine-induced renal insufficiency mouse model, further examination with hematoxylin-eosin staining, Masson staining, and Oil Red O staining revealed alterations in the heart and kidney as well as the accumulation of lipid. Non-invasive blood pressure measurements and ultrasound images demonstrated improvements of peripheral vascular and right ventricular hemodynamic parameters with S-nitroso-L-cysteine (CSNO) inhalation therapy. In cell experiments, knocking down ACAA2 led to accumulation of lipid droplets and exacerbation of oxidative stress in cardiomyocytes, while overexpression of ACAA2 reversed these effects. The transcription factor FOXO4 was found to regulate lipid peroxidation by modulating ACAA2, and knocking down FOXO4 partially restored the expression of ACAA2, reducing oxidative stress in cardiomyocytes. Furthermore, exogenous CSNO effectively restored the expression of ACAA2 and reduced the level of FOXO4, thereby mitigating lipid peroxidation and improving cardiac function. Therefore, in the context of renal insufficiency, regulating the FOXO4-ACAA2 axis through CSNO inhalation therapy may provide a novel therapeutic strategy for alleviating myocardial lipid peroxidation and improving cardiac function.

E3 ubiquitin ligases and deubiquitinases in colorectal cancer: Emerging molecular insights and therapeutic opportunities

Colorectal cancer (CRC) presents ongoing challenges due to limited treatment effectiveness and a discouraging prognosis, underscoring the need for ground-breaking therapeutic approaches. This review delves into the pivotal role of E3 ubiquitin ligases and deubiquitinases (DUBs), underscoring their role as crucial regulators for tumor suppression and oncogenesis in CRC. We spotlight the diverse impact of E3 ligases and DUBs on CRC's biological processes and their remarkable versatility. We closely examine their specific influence on vital signaling pathways, particularly Wnt/β-catenin and NF-κB. Understanding these regulatory mechanisms is crucial for unravelling the complexities of CRC progression. Importantly, we explore the untapped potential of E3 ligases and DUBs as novel CRC treatment targets, discussing aspects that may guide more effective therapeutic strategies. In conclusion, our concise review illuminates the E3 ubiquitin ligases and deubiquitinases pivotal role in CRC, offering insights to inspire innovative approaches for transforming the treatment landscape in CRC.

Pseudokinase STK40 promotes TH1 and TH17 cell differentiation by targeting FOXO transcription factors

Inappropriate CD4+ T helper (TH) cell differentiation leads to progression of inflammatory and autoimmune diseases, yet the regulatory mechanisms governing stability and activity of transcription factors controlling TH cell differentiation remain elusive. Here, we describe how pseudokinase serine threonine kinase 40 (STK40) facilitates TH1/TH17 differentiation under pathological conditions. STK40 in T cells is dispensable for immune homeostasis in resting mice. However, mice with T cell-specific deletion of STK40 exhibit attenuated symptoms of experimental autoimmune encephalomyelitis and colitis, accompanied by diminished TH1 and TH17 cell differentiation. Mechanistically, STK40 facilitates K48-linked polyubiquitination and proteasomal degradation of FOXO1/4 through promoting their interaction with E3 ligase COP1. Inhibition of FOXO4 or FOXO1, respectively, restores differentiation potential of STK40-deficient TH1/TH17 cells. Together, our data suggest a crucial role of STK40 in TH1 and TH17 cell differentiation, thereby enabling better understanding of the molecular regulatory network of CD4+ T cell differentiation and providing effective targets for the treatment of autoimmune diseases.

CSN6-SPOP-HMGCS1 Axis Promotes Hepatocellular Carcinoma Progression via YAP1 Activation

Cholesterol metabolism has important roles in maintaining membrane integrity and countering the development of diseases such as obesity and cancers. Cancer cells sustain cholesterol biogenesis for their proliferation and microenvironment reprograming even when sterols are abundant. However, efficacy of targeting cholesterol metabolism for cancer treatment is always compromised. Here it is shown that CSN6 is elevated in HCC and is a positive regulator of hydroxymethylglutaryl-CoA synthase 1 (HMGCS1) of mevalonate (MVA) pathway to promote tumorigenesis. Mechanistically, CSN6 antagonizes speckle-type POZ protein (SPOP) ubiquitin ligase to stabilize HMGCS1, which in turn activates YAP1 to promote tumor growth. In orthotopic liver cancer models, targeting CSN6 and HMGCS1 hinders tumor growth in both normal and high fat diet. Significantly, HMGCS1 depletion improves YAP inhibitor efficacy in patient derived xenograft models. The results identify a CSN6-HMGCS1-YAP1 axis mediating tumor outgrowth in HCC and propose a therapeutic strategy of targeting non-alcoholic fatty liver diseases- associated HCC.

The involvement of E3 ubiquitin ligases in the development and progression of colorectal cancer

To date, colorectal cancer (CRC) still has limited therapeutic efficacy and poor prognosis and there is an urgent need for novel targets to improve the outcome of CRC patients. The highly conserved ubiquitination modification mediated by E3 ubiquitin ligases is an important mechanism to regulate the expression and function of tumor promoters or suppressors in CRC. In this review, we provide an overview of E3 ligases in modulating various biological processes in CRC, including proliferation, migration, stemness, metabolism, cell death, differentiation and immune response of CRC cells, emphasizing the pluripotency of E3 ubiquitin ligases. We further focus on the role of E3 ligases in regulating vital cellular signal pathways in CRC, such as Wnt/β-catenin pathway and NF-κB pathway. Additionally, considering the potential of E3 ligases as novel targets in the treatment of CRC, we discuss what aspects of E3 ligases can be utilized and exploited for efficient therapeutic strategies.

eIF3f Mediates SGOC Pathway Reprogramming by Enhancing Deubiquitinating Activity in Colorectal Cancer

Numerous studies have demonstrated that individual proteins can moonlight. Eukaryotic Initiation translation factor 3, f subunit (eIF3f) is involved in critical biological functions; however, its role independent of protein translation in regulating colorectal cancer (CRC) is not characterized. Here, it is demonstrated that eIF3f is upregulated in CRC tumor tissues and that both Wnt and EGF signaling pathways are participating in eIF3f's oncogenic impact on targeting phosphoglycerate dehydrogenase (PHGDH) during CRC development. Mechanistically, EGF blocks FBXW7β-mediated PHGDH ubiquitination through GSK3β deactivation, and eIF3f antagonizes FBXW7β-mediated PHGDH ubiquitination through its deubiquitinating activity. Additionally, Wnt signals transcriptionally activate the expression of eIF3f, which also exerts its deubiquitinating activity toward MYC, thereby increasing MYC-mediated PHGDH transcription. Thereby, both impacts allow eIF3f to elevate the expression of PHGDH, enhancing Serine-Glycine-One-Carbon (SGOC) signaling pathway to facilitate CRC development. In summary, the study uncovers the intrinsic role and underlying molecular mechanism of eIF3f in SGOC signaling, providing novel insight into the strategies to target eIF3f-PHGDH axis in CRC.

COPS6 promotes tumor progression and reduces CD8+ T cell infiltration by repressing IL-6 production to facilitate tumor immune evasion in breast cancer

Due to poor T cell infiltration, tumors evade immune surveillance. Increased CD8+ T cell infiltration in breast cancer suggests a satisfactory response to immunotherapy. COPS6 has been identified as an oncogene, but its role in regulating antitumor immune responses has not been defined. In this study, we investigated the impact of COPS6 on tumor immune evasion in vivo. Tumor transplantation models were established in C57BL/6 J mice and BALB/c nude mice. Flow cytometry was conducted to identify the role of COPS6 on tumor-infiltrating CD8+ T cells. By analyzing the TCGA and GTEx cohort, we found that COPS6 expression was significantly up-regulated in a variety of cancers. In human osteosarcoma cell line U2OS and non-small cell lung cancer cell line H1299, we showed that p53 negatively regulated COPS6 promoter activity. In human breast cancer MCF-7 cells, COPS6 overexpression stimulated p-AKT expression as well as the proliferation and malignant transformation of tumor cells, whereas knockdown of COPS6 caused opposite effects. Knockdown of COPS6 also significantly suppressed the growth of mouse mammary cancer EMT6 xenografts in BALB/c nude mice. Bioinformatics analysis suggested that COPS6 was a mediator of IL-6 production in the tumor microenvironment and a negative regulator of CD8+ T cell tumor infiltration in breast cancer. In C57BL6 mice bearing EMT6 xenografts, COPS6 knockdown in the EMT6 cells increased the number of tumor-infiltrating CD8+ T cells, while knockdown of IL-6 in COPS6KD EMT6 cells diminished tumor infiltrating CD8+ T cells. We conclude that COPS6 promotes breast cancer progression by reducing CD8+ T cell infiltration and function via the regulation of IL-6 secretion. This study clarifies the role of p53/COPS6/IL-6/CD8+ tumor infiltrating lymphocytes signaling in breast cancer progression and immune evasion, opening a new path for development of COPS6-targeting therapies to enhance tumor immunogenicity and treat immunologically "cold" breast cancer.

ACTL6A protects gastric cancer cells against ferroptosis through induction of glutathione synthesis

Gastric cancer (GC), one of the most common malignant tumors in the world, exhibits a rapid metastasis rate and causes high mortality. Diagnostic markers and potential therapeutic targets for GCs are urgently needed. Here we show that Actin-like protein 6 A (ACTL6A), encoding an SWI/SNF subunit, is highly expressed in GCs. ACTL6A is found to be critical for regulating the glutathione (GSH) metabolism pathway because it upregulates γ-glutamyl-cysteine ligase catalytic subunit (GCLC) expression, thereby reducing reactive oxygen species (ROS) levels and inhibiting ferroptosis, a regulated form of cell death driven by the accumulation of lipid-based ROS. Mechanistic studies show that ACTL6A upregulates GCLC as a cotranscription factor with Nuclear factor (erythroid-derived 2)-like 2 (NRF2) and that the hydrophobic region of ACTL6A plays an important role. Our data highlight the oncogenic role of ACTL6A in GCs and indicate that inhibition of ACTL6A or GCLC could be a potential treatment strategy for GCs.

FBXW7β loss-of-function enhances FASN-mediated lipogenesis and promotes colorectal cancer growth

Continuous de novo fatty acid synthesis is required for the biosynthetic demands of tumor. FBXW7 is a highly mutated gene in CRC, but its biological functions in cancer are not fully characterized. Here, we report that FBXW7β, a FBXW7 isoform located in the cytoplasm and frequently mutated in CRC, is an E3 ligase of fatty acid synthase (FASN). Cancer-specific FBXW7β mutations that could not degrade FASN can lead to sustained lipogenesis in CRC. COP9 signalosome subunit 6 (CSN6), an oncogenic marker of CRC, increases lipogenesis via interacting with and stabilizing FASN. Mechanistic studies show that CSN6 associates with both FBXW7β and FASN, and antagonizes FBXW7β's activity by enhancing FBXW7β autoubiquitination and degradation, which in turn prevents FBXW7β-mediated FASN ubiquitination and degradation, thereby regulating lipogenesis positively. Both CSN6 and FASN are positively correlated in CRC, and CSN6-FASN axis, regulated by EGF, is responsible for poor prognosis of CRC. The EGF-CSN6-FASN axis promotes tumor growth and implies a treatment strategy of combination of orlistat and cetuximab. Patient-derived xenograft experiments prove the effectiveness of employing orlistat and cetuximab combination in suppressing tumor growth for CSN6/FASN-high CRC. Thus, CSN6-FASN axis reprograms lipogenesis to promote tumor growth and is a target for cancer intervening strategy in CRC.

Role of the gut microbiota in anticancer therapy: from molecular mechanisms to clinical applications

In the past period, due to the rapid development of next-generation sequencing technology, accumulating evidence has clarified the complex role of the human microbiota in the development of cancer and the therapeutic response. More importantly, available evidence seems to indicate that modulating the composition of the gut microbiota to improve the efficacy of anti-cancer drugs may be feasible. However, intricate complexities exist, and a deep and comprehensive understanding of how the human microbiota interacts with cancer is critical to realize its full potential in cancer treatment. The purpose of this review is to summarize the initial clues on molecular mechanisms regarding the mutual effects between the gut microbiota and cancer development, and to highlight the relationship between gut microbes and the efficacy of immunotherapy, chemotherapy, radiation therapy and cancer surgery, which may provide insights into the formulation of individualized therapeutic strategies for cancer management. In addition, the current and emerging microbial interventions for cancer therapy as well as their clinical applications are summarized. Although many challenges remain for now, the great importance and full potential of the gut microbiota cannot be overstated for the development of individualized anti-cancer strategies, and it is necessary to explore a holistic approach that incorporates microbial modulation therapy in cancer.

Tespa1 facilitates hematopoietic and leukemic stem cell maintenance by restricting c-Myc degradation

Hematopoietic stem cells (HSCs) and leukemia stem cells (LSCs) have robust self-renewal potential, which is responsible for sustaining normal and malignant hematopoiesis, respectively. Although considerable efforts have been made to explore the regulation of HSC and LSC maintenance, the underlying molecular mechanism remains obscure. Here, we observe that the expression of thymocyte-expressed, positive selection-associated 1 (Tespa1) is markedly increased in HSCs after stresses exposure. Of note, deletion of Tespa1 results in short-term expansion but long-term exhaustion of HSCs in mice under stress conditions due to impaired quiescence. Mechanistically, Tespa1 can interact with CSN subunit 6 (CSN6), a subunit of COP9 signalosome, to prevent ubiquitination-mediated degradation of c-Myc protein in HSCs. As a consequence, forcing c-Myc expression improves the functional defect of Tespa1-null HSCs. On the other hand, Tespa1 is identified to be highly enriched in human acute myeloid leukemia (AML) cells and is essential for AML cell growth. Furthermore, using MLL-AF9-induced AML model, we find that Tespa1 deficiency suppresses leukemogenesis and LSC maintenance. In summary, our findings reveal the important role of Tespa1 in promoting HSC and LSC maintenance and therefore provide new insights on the feasibility of hematopoietic regeneration and AML treatment.

E3 Ubiquitin Ligase Constitutive Photomorphogenic 1 Regulates Differentiation and Inflammation via MAPK Signaling Pathway in Rabbit Articular Chondrocytes

Constitutive photomorphogenic 1 (COP1), is an E3 ubiquitin ligase that plays a role in the regulation of various cellular processes including cell growth, differentiation, and survival in mammals. In certain conditions such as overexpression or loss of function, COP1 acts either as an oncogenic protein or as a tumor suppressor by targeting specific proteins for ubiquitination-mediated degradation. However, the precise role of COP1 has not been well studied in primary articular chondrocytes. In this study, we investigated the role of COP1 in chondrocyte differentiation. Western blotting and reverse transcription-polymerase chain reaction analysis demonstrated that COP1 overexpression reduced type II collagen expression, promoted cyclooxygenase 2 (COX-2) expression, and reduced sulfated proteoglycan synthesis, as detected by Alcian blue staining. Upon siRNA treatment, revived type II collagen, sulfated proteoglycan production, and decreased COX-2 expression. Phosphorylation of p38 kinase and ERK-1/-2 signaling pathways was regulated by COP1 upon cDNA and siRNA transfection in chondrocytes. The inhibition of the p38 kinase and ERK-1/-2 signaling pathways with SB203580 and PD98059 ameliorated the expression of type II collagen and COX-2 in transfected chondrocytes, thus suggesting that COP1 regulates differentiation and inflammation in rabbit articular chondrocytes via the p38 kinase and ERK-1/-2 signaling pathway.

FoxO3 and oxidative stress: a multifaceted role in cellular adaptation

Oxidative stress is a major cause of morbidity and mortality in human health and disease. In this review, we focus on the Forkhead Box (Fox) subclass O3 (FoxO3), an extensively studied transcription factor that plays a pleiotropic role in a wide range of physiological and pathological processes by regulating multiple gene regulatory networks involved in the modulation of numerous aspects of cellular metabolism, including fuel metabolism, cell death, and stress resistance. This review will also focus on regulatory mechanisms of FoxO3 expression and activity, such as crucial post-translational modifications and non-coding RNAs. Moreover, this work discusses and evidences some pathways to how this transcription factor and reactive oxygen species regulate each other, which may lead to the pathogenesis of various types of diseases. Therefore, in addition to being a promising therapeutic target, the FoxO3-regulated signaling pathways can also be used as reliable diagnostic and prognostic biomarkers and indicators for drug responsiveness.

Smurf2-Mediated Ubiquitination of FOXO4 Regulates Oxygen-glucose Deprivation/Reperfusion-induced Pyroptosis of Cortical Neurons

BACKGROUND

Smad ubiquitination regulatory factor 2 (Smurf2) has been observed to alleviate ischemia-reperfusion injury. This study sought to explore the molecular mechanism of Smurf2-mediated forkhead box O4 (FOXO4) ubiquitination in oxygen-glucose deprivation/ reperfusion (OGD/R)-induced pyroptosis of cortical neurons.

METHODS

Human cortical neurons (HCN-2) were subjected to OGD/R to establish a cell model of cerebral stroke. Smurf2, FOXO4, and doublecortin domain containing 2 (DCDC2) expressions were determined by RT-qPCR and Western blot. LDH release, pyroptosis-related proteins NLRP3, GSDMD-N, and cleaved-caspase-3, as well as inflammatory factors IL-1β and IL-18, were assessed by LDH assay kit, Western blot, and ELISA. The ubiquitination level of FOXO4 was determined by ubiquitination assay. The bindings of Smurf2 to FOXO4 and FOXO4 to DCDC2 were testified by Co-IP, ChIP, and dual-luciferase assays. Rescue experiments were designed to validate the role of FOXO4/DCDC2 in the pyroptosis of HCN-2 cells.

RESULTS

Smurf2 was weakly expressed, while FOXO4 and DCDC2 were prominently expressed in OGD/R-treated HCN-2 cells. Smurf2 overexpression promoted LDH release, reduced NLRP3, GSDMD-N, and cleaved-caspase-3 proteins, and decreased IL-1β and IL-18 concentrations. Sumrf2 improved the ubiquitination level of FOXO4 to downregulate its protein level. FOXO4 is bound to the DCDC2 promoter to facilitate its transcription. Overexpression of FOXO4 or DCDC2 reversed the inhibition of Smurf2 overexpression on pyroptosis of OGD/Rtreated HCN-2 cells.

CONCLUSION

Smurf2 overexpression facilitated the ubiquitination of FOXO4 to reduce its protein level, thereby suppressing DCDC2 transcription and restricting OGD/R-induced pyroptosis of cortical neurons.

Therapeutic potential of Clostridium butyricum anticancer effects in colorectal cancer

Probiotic roles of Clostridium butyricum (C.B) are involved in regulating disease and cancers, yet the mechanistic basis for these regulatory roles remains largely unknown. Here, we demonstrate that C.B reprograms the proliferation, migration, stemness, and tumor growth in CRC by regulating pivotal signal molecules including MYC. Destabilization of MYC by C.B supplementation suppresses cancer cell proliferation/metastasis, sensitizes 5-FU treatment, and boosts responsiveness of anti-PD1 therapy. MYC is a transcriptional regulator of Thymidylate synthase (TYMS), a key target of the 5-FU. Also MYC is known to impact on PD-1 expression. Mechanistically, C.B treatment of CRC cells results in MYC degradation by enhancing proteasome-mediated ubiquitination, thereby mitigating MYC-mediated 5-FU resistance and boosting anti-PD1 immunotherapeutic efficacy. Together, our findings uncover previously unappreciated links between C.B and CRC cell signaling, providing insight into the tumorigenesis modulating mechanisms of C.B in boosting chemo/immune therapies.

The COP9 signalosome: A versatile regulatory hub of Cullin-RING ligases

The COP9 signalosome (CSN) is a universal regulator of Cullin-RING ubiquitin ligases (CRLs) - a family of modular enzymes that control various cellular processes via timely degradation of key signaling proteins. The CSN, with its eight-subunit architecture, employs multisite binding of CRLs and inactivates CRLs by removing a small ubiquitin-like modifier named neural precursor cell-expressed, developmentally downregulated 8 (Nedd8). Besides the active site of the catalytic subunit CSN5, two allosteric sites are present in the CSN, one of which recognizes the substrate recognition module and the presence of CRL substrates, and the other of which can 'glue' the CSN-CRL complex by recruitment of inositol hexakisphosphate. In this review, we present recent findings on the versatile regulation of CSN-CRL complexes.

The chromatin remodeler CHD6 promotes colorectal cancer development by regulating TMEM65-mediated mitochondrial dynamics via EGF and Wnt signaling

Chromodomain helicase DNA binding protein (CHD) family plays critical roles in regulating gene transcription. The family is linked to cancer disease, but the family member's role in tumorigenesis remains largely unknown. Here, we report that CHD6 is highly expressed in colorectal cancer (CRC). CHD6 knockdown inhibited cancer cell proliferation, migration, invasion, and tumorigenesis. Consistently, Villin-specific Chd6 knockout in mice attenuates cancer formation in AOM/DSS model. We found that aberrant EGF signals promoted the stability of CHD6 by diminishing ubiquitin-mediated degradation. EGF signal inhibits GSK3β activity, which in turn prevents phosphodegron formation of CHD6, thereby hindering E3 ligase FBXW7-mediated CHD6 ubiquitination and degradation. CHD6's chromatin remodeler activity engages in binding Wnt signaling transcription factor TCF4 to facilitate the transcriptional expression of TMEM65, a mitochondrial inner membrane protein involved in ATP production and mitochondrial dynamics. In addition, Wnt signaling is also an upstream regulator of CHD6. CHD6 promoter contains TCF4 and β-catenin binding site, and CHD6 can be transcriptionally activated by Wnt ligand to facilitate TMEM65 transcription. Thus CHD6-TMEM65 axis can be regulated by both EGF and Wnt signaling pathways through two different mechanisms. We further illustrate that CHD6-TMEM65 axis is deregulated in cancer and that co-administration of Wnt inhibitor LGK974 and the anti-EGFR monoclonal antibody cetuximab largely restricted the growth of patient-derived xenografts of CRC. Targeting CHD6-TMEM65 axis may be effective for cancer intervention.

Correlations of ALD, Keap-1, and FoxO4 expression with traditional tumor markers and clinicopathological characteristics in colorectal carcinoma

Aldolase A (A-2) (ALD), Kelch-like-ECH associated protein-1 (Keap-1), and Forkhead box O4 (FoxO4) are key regulatory proteins, which have been proven to be involved in tumor development. However, the clinicopathological significance of ALD, Keap-1, and FoxO4 expressions in colorectal (colon) carcinoma (CRC) is not clearly known. We sought to explore the clinicopathological significance of ALD, Keap-1, and FoxO4 in CRC to provide evidences for potential monitoring index of CRC. Cases of 199 CRC patients were analyzed retrospectively. Evaluation of ALD, cAMP response element-binding protein-2, cyclo-oxygenase 2, FoxO4, Keap-1, and p53 expressions in CRC patients was accomplished with immunohistochemical technique. The patients were divided into negative and positive groups in accordance with immunohistochemical result. We compared the clinicopathological characteristics of the patients in the 2 groups, coupled with analysis of the relationship between 6 aforesaid proteins and clinicopathological characteristics. Herein, we confirmed the association of tumor location with the expression of ALD, Keap-1, and FoxO4. Also, tumor differentiation was observed to associate significantly with the expression of Keap-1, FoxO4, and Cox-2. The data also revealed that there was a correlation between smoking and expression of ALD, Keap-1, FoxO4, p53, and Cox-2. Nevertheless, insignificant difference was observed when clinicopathological characteristics were compared with cAMP response element-binding protein-2 expression. These findings suggest that ALD, Keap-1, and FoxO4 reinvolved in CRC development, and thus may be considered as potential monitoring protein for CRC.

UBP12 and UBP13 deubiquitinases destabilize the CRY2 blue light receptor to regulate Arabidopsis growth

Light is a crucial exogenous signal sensed by cryptochrome (CRY) blue light receptors to modulate growth and the circadian clock in plants and animals. However, how CRYs interpret light quantity to regulate growth in plants remains poorly understood. Furthermore, CRY2 protein levels and activity are tightly regulated in light to fine-tune hypocotyl growth; however, details of the mechanisms that explain precise control of CRY2 levels are not fully understood. We show that in Arabidopsis, UBP12 and UBP13 deubiquitinases physically interact with CRY2 in light. UBP12/13 negatively regulates CRY2 by promoting its ubiquitination and turnover to modulate hypocotyl growth. Growth and development were explicitly affected in blue light when UBP12/13 were disrupted or overexpressed, indicating their role alongside CRY2. UBP12/13 also interacted with and stabilized COP1, which is partially required for CRY2 turnover. Our combined genetic and molecular data support a mechanistic model in which UBP12/13 interact with CRY2 and COP1, leading to the stabilization of COP1. Stabilized COP1 then promotes the ubiquitination and degradation of CRY2 under blue light. Despite decades of studies on deubiquitinases, the knowledge of how their activity is regulated is limited. Our study provides insight into how exogenous signals and ligands, along with their receptors, regulate deubiquitinase activity by protein-protein interaction. Collectively, our results provide a framework of cryptochromes and deubiquitinases to detect and interpret light signals to control plant growth at the most appropriate time.

Roles of lncRNA LVBU in regulating urea cycle/polyamine synthesis axis to promote colorectal carcinoma progression

Altered expression of Urea Cycle (UC) enzymes occurs in many tumors, resulting a metabolic hallmark termed as UC dysregulation. Polyamines are synthesized from ornithine, and polyamine synthetic genes are elevated in various tumors. However, the underlying deregulations of UC/ polyamine synthesis in cancer remain elusive. Here, we characterized a hypoxia-induced lncRNA LVBU (lncRNA regulation via BCL6/urea cycle) that is highly expressed in colorectal cancer (CRC) and correlates with poor cancer prognosis. Increased LVBU expression promoted CRC cells proliferation, foci formation and tumorigenesis. Further, LVBU regulates urea cycle and polyamine synthesis through BCL6, a negative regulator of p53. Mechanistically, overexpression of LVBU competitively bound miR-10a/miR-34c to protect BCL6 from miR-10a/34c-mediated degradation, which in turn allows BCL6 to block p53-mediated suppression of genes (arginase1 ARG1, ornithine transcarbamylase OTC, ornithine decarboxylase 1 ODC1) involved in UC/polyamine synthesis. Significantly, ODC1 inhibitor attenuated the growth of patient derived xenografts (PDX) that sustain high LVBU levels. Taken together, elevated LVBU can regulate BCL6-p53 signaling axis for systemic UC/polyamine synthesis reprogramming and confers a predilection toward CRC development. Our data demonstrates that further drug development and clinical evaluation of inhibiting UC/polyamine synthesis are warranted for CRC patients with high expression of LVBU.

The FOXO family of transcription factors: key molecular players in gastric cancer

Gastric cancer (GC) is the fifth most frequently diagnosed cancer worldwide and the third leading cause of cancer-related death with an oncological origin. Despite its decline in incidence and mortality in recent years, GC remains a global public problem that seriously threatens patients' health and lives. The forkhead box O proteins (FOXOs) are a family of evolutionarily conserved transcription factors (TFs) with crucial roles in cell fate decisions. In mammals, the FOXO family consists of four members FOXO1, 3a, 4, and 6. FOXOs play crucial roles in a variety of biological processes, such as development, metabolism, and stem cell maintenance, by regulating the expression of their target genes in space and time. An accumulating amount of evidence has shown that the dysregulation of FOXOs is involved in GC progression by affecting multiple cellular processes, including proliferation, apoptosis, invasion, metastasis, cell cycle progression, carcinogenesis, and resistance to chemotherapeutic drugs. In this review, we systematically summarize the recent findings on the regulatory mechanisms of FOXO family expression and activity and elucidate its roles in GC progression. Moreover, we also highlight the clinical implications of FOXOs in GC treatment.

Metabolomic analyses reveal new stage-specific features of COVID-19

The current pandemic of coronavirus disease 2019 (COVID-19) has affected >160 million individuals to date, and has caused millions of deaths worldwide, at least in part due to the unclarified pathophysiology of this disease. Identifying the underlying molecular mechanisms of COVID-19 is critical to overcome this pandemic. Metabolites mirror the disease progression of an individual and can provide extensive insights into their pathophysiological significance at each stage of disease. We provide a comprehensive view of metabolic characterisation of sera from COVID-19 patients at all stages using untargeted and targeted metabolomic analysis. As compared with the healthy controls, we observed different alteration patterns of circulating metabolites from the mild, severe and recovery stages, in both the discovery cohort and the validation cohort, which suggests that metabolic reprogramming of glucose metabolism and the urea cycle are potential pathological mechanisms for COVID-19 progression. Our findings suggest that targeting glucose metabolism and the urea cycle may be a viable approach to fight COVID-19 at various stages along the disease course.

High-Fat Diet-Induced Fatty Liver Is Associated with Immunosuppressive Response during Sepsis in Mice

High-fat diet-induced fatty liver is an indolent and chronic disease accompanied by immune dysfunction and metabolic disturbances involving numerous biological pathways. This study investigated how this abnormal metabolic disorder influences sepsis in mice. Mice were fed with normal chow (NC) or high-fat diet (HFD), and palmitic acid (PA) was used to treat hepatocytes to mimic fat accumulation in vitro. Lipopolysaccharide (LPS) was used to induce sepsis and related immune responses. Mice fed on a high-fat diet displayed higher mortality and more severe liver damage but compromised immunoreaction. The supernatant from PA-treated primary hepatocytes markedly diminished the inflammatory cytokine expression of macrophages after LPS stimulation, which showed a state of immunosuppression. Metabolomics analysis indicated the level of many key metabolites with possible roles in immunoreaction was altered in the HFD and PA groups compared with corresponding controls; specifically, β-hydroxybutyric acid (BHB) showed an immunosuppressive effect on Raw264.7 cells during the LPS stimulation. Transcriptomic analysis suggested that several differential signaling pathways may be associated with the alteration of immune function between the NC and HFD groups, as well as in the in vitro model. Our study suggests that the consumption of HFD may alter the hepatic metabolic profile, and that certain metabolites may remold the immune system to immunosuppressive state in the context of sepsis.

FOXO4 Inhibits the Migration and Metastasis of Colorectal Cancer by Regulating the APC2/β-Catenin Axis

Objective: Adenomatous polyposis coli 2 (APC2) is a colorectal cancer (CRC) tumor-suppressor gene. The progression of several kinds of cancer is closely associated with Forkhead box O4 (FOXO4). However, the function of FOXO4 in CRC is unclear. This study focused on the role of FOXO4 and the relationship between FOXO4 and APC2 in CRC migration and metastasis.

Methods: The expressions of FOXO4, APC2, and p(S37)-β-catenin were detected in CRC tissues by immunohistochemistry, and their correlation was analyzed using the Spearman coefficient. Chromatin immunoprecipitation was used to test whether FOXO4 binds and regulates APC2 as a transcription factor. Either FOXO4 overexpression or APC2 knockdown was performed in CRC cell lines. The roles of FOXO4 and APC2 were investigated in CRC migration and metastasis.

Results: FOXO4 was downregulated in CRC tissues compared with normal tissues and positively correlated with APC2 and p(S37)-β-catenin. FOXO4 could combine the promoter region of APC2 to upregulate its expression and increase the phosphorylated degradation of β-catenin. Stemness genes (CD133, ABCG1, and SOX2) were inhibited by FOXO4 overexpression in SW620 and HCT116 cell lines. Overexpressed FOXO4 suppressed epithelial–mesenchymal transition and the migration of CRC cell lines and metastasis of HCT116 in both the spleen and liver of nude mice, which was reversed by APC2 knockdown.

Conclusion: This research demonstrates that overexpressed FOXO4 inhibits the migration and metastasis of CRC cells by enhancing the APC2/β-catenin axis, suggesting that FOXO4 is a potential therapeutic target of CRC.

Harness the functions of gut microbiome in tumorigenesis for cancer treatment

It has been shown that gut microbiota dysbiosis leads to physiological changes and links to a number of diseases, including cancers. Thus, many cancer categories and treatment regimens should be investigated in the context of the microbiome. Owing to the availability of metagenome sequencing and multiomics studies, analyses of species characterization, host genetic changes, and metabolic profile of gut microbiota have become feasible, which has facilitated an exponential knowledge gain about microbiota composition, taxonomic alterations, and host interactions during tumorigenesis. However, the complexity of the gut microbiota, with a plethora of uncharacterized host‐microbe, microbe‐microbe, and environmental interactions, still contributes to the challenge of advancing our knowledge of the microbiota‐cancer interactions. These interactions manifest in signaling relay, metabolism, immunity, tumor development, genetic instability, sensitivity to cancer chemotherapy and immunotherapy. This review summarizes current studies/molecular mechanisms regarding the association between the gut microbiota and the development of cancers, which provides insights into the therapeutic strategies that could be harnessed for cancer diagnosis, treatment, or prevention.

Chronic Jet Lag Exacerbates Jejunal and Colonic Microenvironment in Mice

Background

Evidence suggests that circadian rhythm disorder is associated with a variety of gastrointestinal diseases, and the circadian rhythm plays a key role in maintaining the homeostasis of intestinal flora. The underlying mechanisms are still not completely identified. This study was aimed to explore whether jet lag-caused circadian disruption influences gut microbiome and its metabolites.

Methods

Mice were synchronized with 12-h light/dark cycles (control group) or subjected to daily 8-h advance of the light/dark cycle for every 3 days (jet-lagged group). Four months later, fecal samples and jejunal contents were collected and analyzed by 16S rRNA gene sequencing. In addition, fecal samples were subjected to metabolome analysis with ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS).

Results

The results of 16s rRNA sequencing showed that chronic jet lag led to decreased microbial abundance, richness, and diversity in both feces and jejunal contents. ANOSIM analysis revealed significant difference between control and jet-lagged groups. As the colonic microbiome, the abundance of Bacteroidetes phylum was significantly decreased and that of Actinobacteria phylum was increased in jet-lagged mice. Jet lag increased the ratio of Firmicutes to Bacteroidetes, an indicator for the imbalance of gut microbiota. Metabolome analysis of fecal samples showed that the levels of tryptophan and its derivatives were decreased in jet-lagged mice. In addition, fecal levels of secondary bile acids changed under jet lag conditions. Correlation analysis identified associations between tryptophan (and its derivatives) levels and colonic microbiota.

Conclusions

This study presents a comprehensive landscape of gut microbiota and its metabolites in mice subjected to chronic jet lag. The results suggest that circadian disruption may lead to changes in fecal and jejunal microbiota and fecal metabolites. Moreover, our results demonstrate a novel interplay between the gut microbiome and metabolome.

Impact of diabetes on promoting the growth of breast cancer

BACKGROUND

Type II diabetes mellitus (DM2) is a significant risk factor for cancers, including breast cancer. However, a proper diabetic breast cancer mouse model is not well-established for treatment strategy design. Additionally, the precise diabetic signaling pathways that regulate cancer growth remain unresolved. In the present study, we established a suitable mouse model and demonstrated the pathogenic role of diabetes on breast cancer progression.

METHODS

We successfully generated a transgenic mouse model of human epidermal growth factor receptor 2 positive (Her2⁺ or ERBB2) breast cancer with DM2 by crossing leptin receptor mutant (Lepr^db/+ ) mice with MMTV-ErbB2/neu) mice. The mouse models were administrated with antidiabetic drugs to assess the impacts of controlling DM2 in affecting tumor growth. Magnetic resonance spectroscopic imaging was employed to analyze the tumor metabolism.

RESULTS

Treatment with metformin/rosiglitazone in MMTV-ErbB2/Lepr^db/db mouse model reduced serum insulin levels, prolonged overall survival, decreased cumulative tumor incidence, and inhibited tumor progression. Anti-insulin resistance medications also inhibited glycolytic metabolism in tumors in vivo as indicated by the reduced metabolic flux of hyperpolarized ¹³ C pyruvate-to-lactate reaction. The tumor cells from MMTV-ErbB2/Lepr^db/db transgenic mice treated with metformin had reprogrammed metabolism by reducing levels of both oxygen consumption and lactate production. Metformin decreased the expression of Myc and pyruvate kinase isozyme 2 (PKM2), leading to metabolism reprogramming. Moreover, metformin attenuated the mTOR/AKT signaling pathway and altered adipokine profiles.

CONCLUSIONS

MMTV-ErbB2/Lepr^db/db mouse model was able to recapitulate diabetic HER2⁺ human breast cancer. Additionally, our results defined the signaling pathways deregulated in HER2⁺ breast cancer under diabetic condition, which can be intervened by anti-insulin resistance therapy.