Proteasomal degradation of the tumour suppressor FBW7 requires branched ubiquitylation by TRIP12

Molecular insights and clinical implications for the tumor suppressor role of SCFFBXW7 E3 ubiquitin ligase

FBXW7 is one of the most well-characterized F-box proteins, serving as substrate receptor subunit of SKP1-CUL1-F-box (SCF) E3 ligase complexes. SCFFBXW7 is responsible for the degradation of various oncogenic proteins such as cyclin E, c-MYC, c-JUN, NOTCH, and MCL1. Therefore, FBXW7 functions largely as a major tumor suppressor. In keeping with this notion, FBXW7 gene mutations or downregulations have been found and reported in many types of malignant tumors, such as endometrial, colorectal, lung, and breast cancers, which facilitate the proliferation, invasion, migration, and drug resistance of cancer cells. Therefore, it is critical to review newly identified FBXW7 regulation and tumor suppressor function under physiological and pathological conditions to develop effective strategies for the treatment of FBXW7-altered cancers. Since a growing body of evidence has revealed the tumor-suppressive activity and role of FBXW7, here, we updated FBXW7 upstream and downstream signaling including FBXW7 ubiquitin substrates, the multi-level FBXW7 regulatory mechanisms, and dysregulation of FBXW7 in cancer, and discussed promising cancer therapies targeting FBXW7 regulators and downstream effectors, to provide a comprehensive picture of FBXW7 and facilitate the study in this field.

The E3 ubiquitin ligase TRIP12 is required for pancreatic acinar cell plasticity and pancreatic carcinogenesis

The E3 ubiquitin ligase thyroid hormone receptor interacting protein 12 (TRIP12) has been implicated in pancreatic adenocarcinoma (PDAC) through its role in mediating the degradation of pancreas transcription factor 1a (PTF1a). PTF1a is a transcription factor essential for the acinar differentiation state that is notably diminished during the early steps of pancreatic carcinogenesis. Despite these findings, the direct involvement of TRIP12 in the onset of pancreatic cancer has yet to be established. In this study, we demonstrated that TRIP12 protein was significantly upregulated in human pancreatic preneoplastic lesions. Furthermore, we observed that TRIP12 overexpression varied within PDAC samples and PDAC-derived cell lines. We further demonstrated that TRIP12 was required for PDAC-derived cell growth and for the expression of E2F-targeted genes. Acinar-to-ductal cell metaplasia (ADM) is a reversible process that reflects the high plasticity of acinar cells. ADM becomes irreversible in the presence of oncogenic Kras mutations and leads to the formation of preneoplastic lesions. Using two genetically modified mouse models, we showed that a loss of TRIP12 prevented acini from developing ADM in response to pancreatic injury. With two additional mouse models, we further discovered that a depletion of TRIP12 prevented the formation of KrasG12D-induced preneoplastic lesions and impaired metastasis formation in the presence of mutated KrasG12D and Trp53R172H genes. In summary our study identified an overexpression of TRIP12 from the early stages of pancreatic carcinogenesis and proposed this E3 ubiquitin ligase as a novel regulator of acinar plasticity with an important dual role in initiation and metastatic steps of PDAC. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

[High expression of UBE2S promotes progression of hepatocellular carcinoma by increasing cancer cell stemness]

OBJECTIVE

To investigate the expression of the ubiquitination enzyme UBE2S in different cell types in hepatocellular carcinoma (HCC) microenvironment and its impact on proliferation and stemness of HCC cells.

METHODS

TCGA and CPTAC database were used to analyze the transcriptional and promoter methylation levels and protein expressions of UBE2S in HCC. Specific expression patterns of UBE2S, intercellular communication and key transcription factors in different cell types were analyzed based on single-cell sequencing data from TISCH website. We further examined UBE2S expressions in clinical samples of HCC tissues, HCC cells and T cells using immunohistochemistry and immunofluorescence staining. We also tested the effects of UBE2S knockdown on stemness of HCC-LM3 and HepG2 cells using clone formation experiments and sphere formation assay.

RESULTS

Analysis based on TCGA database suggested significant overexpression of UBE2S in both paired and non-paired tumor tissues (P < 0.001), and its transcriptional level increased with tumor grades. The methylation level of UBE2S promoter was significantly decreased in HCC (P < 0.001), and its transcription level increased obviously in HCC with TP53 mutation (P < 0.001). Analysis of CPTAC database also demonstrated overexpression of UBE2S protein in HCC tissues (P < 0.001). Three prognostic models suggested that HCC patients with high UBE2S expression had poorer prognosis (P < 0.001). Single-cell sequencing data analysis revealed high expressions of UBE2S in T cells and high intensities of interaction between endothelial cells, epithelial cells and fibroblasts in HCC microenvironment. Immunohistochemistry and immunofluorescence staining demonstrated high UBE2S expressions in clinical samples of HCC tissues, HCC cells and T cells. In HCC-LM3 and HepG2 cells, UBE2S knockdown significantly inhibited cell clone formation and tumor sphere formation (P < 0.05).

CONCLUSION

UBE2S is highly expressed in T cells in HCC microenvironment in close correlation with a poor prognosis. High UBE2S expression promotes the stemness of HCC cells.

E3 ubiquitin ligase Hul6 modulates iron-dependent metabolism by regulating Php4 stability

Schizosaccharomyces pombe Php4 is the regulatory subunit of the CCAAT-binding complexes and plays an important role in the regulation of iron homeostasis and iron-dependent metabolism. Here, we show that Php4 undergoes ubiquitin-dependent degradation in the late logarithmic and stationary phases. The degradation and ubiquitination of Php4 could be attenuated by deletion of hul6, a gene encoding a putative HECT-type E3 ubiquitin ligase. The expression levels of Hul6 and Php4 are oppositely regulated during cell growth. Hul6 interacts with the C-terminal region of Php4. Two lysine residues (K217 and K274) located in the C-terminal region of Php4 are required for its polyubiquitination. Increasing the levels of Php4 by deletion of hul6 or overexpression of php4 decreased expression of Php4 target proteins involved in iron-dependent metabolic pathways such as the tricarboxylic cycle and mitochondrial oxidative phosphorylation, thus causing increased sensitivity to high-iron and reductions in succinate dehydrogenase and mitochondrial complex II activities. Hul6 is located primarily in the mitochondrial outer membrane and most likely targets cytosolic Php4 for ubiquitination and degradation. Taken together, our data suggest that Hul6 regulates iron-dependent metabolism through degradation of Php4 under normal growth conditions. Our results also suggest that Hul6 promotes iron-dependent metabolism to help the cell to adapt to a nutrient-starved growth phase.

circEPB41L2 blocks the progression and metastasis in non-small cell lung cancer by promoting TRIP12-triggered PTBP1 ubiquitylation

The metastasis of non-small cell lung cancer (NSCLC) is the leading death cause of NSCLC patients, which requires new biomarkers for precise diagnosis and treatment. Circular RNAs (circRNAs), the novel noncoding RNA, participate in the progression of various cancers as microRNA or protein sponges. We revealed the mechanism by which circEPB41L2 (hsa_circ_0077837) blocks the aerobic glycolysis, progression and metastasis of NSCLC through modulating protein metabolism of PTBP1 by the E3 ubiquitin ligase TRIP12. With ribosomal RNA-depleted RNA seq, 57 upregulated and 327 downregulated circRNAs were identified in LUAD tissues. circEPB41L2 was selected due to its dramatically reduced levels in NSCLC tissues and NSCLC cells. Interestingly, circEPB41L2 blocked glucose uptake, lactate production, NSCLC cell proliferation, migration and invasion in vitro and in vivo. Mechanistically, acting as a scaffold, circEPB41L2 bound to the RRM1 domain of the PTBP1 and the E3 ubiquitin ligase TRIP12 to promote TRIP12-mediated PTBP1 polyubiquitylation and degradation, which could be reversed by the HECT domain mutation of TRIP12 and circEPB41L2 depletion. As a result, circEPB41L2-induced PTBP1 inhibition led to PTBP1-induced PKM2 and Vimentin activation but PKM1 and E-cadherin inactivation. These findings highlight the circEPB41L2-dependent mechanism that modulates the "Warburg Effect" and EMT to inhibit NSCLC development and metastasis, offering an inhibitory target for NSCLC treatment.

Simultaneous CRISPR screening and spatial transcriptomics reveals intracellular, intercellular, and functional transcriptional circuits

Pooled optical screens have enabled the study of cellular interactions, morphology, or dynamics at massive scale, but have not yet leveraged the power of highly-plexed single-cell resolved transcriptomic readouts to inform molecular pathways. Here, we present Perturb-FISH, which bridges these approaches by combining imaging spatial transcriptomics with parallel optical detection of in situ amplified guide RNAs. We show that Perturb-FISH recovers intracellular effects that are consistent with Perturb-seq results in a screen of lipopolysaccharide response in cultured monocytes, and uncover new intercellular and density-dependent regulation of the innate immune response. We further pair Perturb-FISH with a functional readout in a screen of autism spectrum disorder risk genes, showing common calcium activity phenotypes in induced pluripotent stem cell derived astrocytes and their associated genetic interactions and dysregulated molecular pathways. Perturb-FISH is thus a generally applicable method for studying the genetic and molecular associations of spatial and functional biology at single-cell resolution.

EZH2 K63-polyubiquitination affecting migration in extranodal natural killer/T-cell lymphoma

BACKGROUND

Overexpressed EZH2 is oncogenically involved in the pathogenesis of different cancerous contexts including extranodal natural killer/T cell lymphoma (ENKTL). However, the underlying mechanisms of EZH2 upregulation have not been fully clarified and it is still difficult to target EZH2 in ENKTL.

RESULTS

Current study identifies an E3 ligase TRIP12 that triggers K63-linked polyubiquitination of EZH2 in ENKTL and unexpectedly, stabilizes EZH2. As determined by gene expression profiling (GEP), TRIP12 and EZH2 levels correlate with each other in ENKTL patient samples. Aided by quantitative mass spectrometry (MS) and follow-up analysis, we identify K634 as the ubiquitination site of EZH2. Further study confirms that TRIP12-mediated EZH2 K634 ubiquitination enhances the interaction between EZH2 and SUZ12 or CDK1 and increases the level of EZH2 T487 phosphorylation. This study further demonstrates the TRIP12-EZH2 signaling might be regulated by cytoplasmic HSP60. Importantly, the TRIP12-EZH2 axis mediates ENKTL cell migration via accelerating epithelial-mesenchymal transition (EMT). Moreover, our study finds out dexamethasone treatment manipulates TRIP12-EZH2 signaling and may represent a novel therapeutic strategy against ENKTL metastasis.

CONCLUSIONS

Altogether, TRIP12 induces K63-linked site-specific polyubiquitination of EZH2 for stabilization, which promotes ENKTL cell migration and could be targeted by dexamethasone treatment.

Control of TGFβ signalling by ubiquitination independent function of E3 ubiquitin ligase TRIP12

Transforming growth factor β (TGFβ) pathway is a master regulator of cell proliferation, differentiation, and death. Deregulation of TGFβ signalling is well established in several human diseases including autoimmune disorders and cancer. Thus, understanding molecular pathways governing TGFβ signalling may help better understand the underlying causes of some of those conditions. Here, we show that a HECT domain E3 ubiquitin ligase TRIP12 controls TGFβ signalling in multiple models. Interestingly, TRIP12 control of TGFβ signalling is completely independent of its E3 ubiquitin ligase activity. Instead, TRIP12 recruits SMURF2 to SMAD4, which is most likely responsible for inhibitory monoubiquitination of SMAD4, since SMAD4 monoubiquitination and its interaction with SMURF2 were dramatically downregulated in TRIP12-/- cells. Additionally, genetic inhibition of TRIP12 in human and murine cells leads to robust activation of TGFβ signalling which was rescued by re-introducing wildtype TRIP12 or a catalytically inactive C1959A mutant. Importantly, TRIP12 control of TGFβ signalling is evolutionary conserved. Indeed, genetic inhibition of Drosophila TRIP12 orthologue, ctrip, in gut leads to a reduced number of intestinal stem cells which was compensated by the increase in differentiated enteroendocrine cells. These effects were completely normalised in Drosophila strain where ctrip was co-inhibited together with Drosophila SMAD4 orthologue, Medea. Similarly, in murine 3D intestinal organoids, CRISPR/Cas9 mediated genetic targeting of Trip12 enhances TGFβ mediated proliferation arrest and cell death. Finally, CRISPR/Cas9 mediated genetic targeting of TRIP12 in MDA-MB-231 breast cancer cells enhances the TGFβ induced migratory capacity of these cells which was rescued to the wildtype level by re-introducing wildtype TRIP12. Our work establishes TRIP12 as an evolutionary conserved modulator of TGFβ signalling in health and disease.

Assembly and disassembly of branched ubiquitin chains

Protein ubiquitylation is an essential post-translational modification that regulates nearly all aspects of eukaryotic cell biology. A diverse collection of ubiquitylation signals, including an extensive repertoire of polymeric ubiquitin chains, leads to a range of different functional outcomes for the target protein. Recent studies have shown that ubiquitin chains can be branched and that branched chains have a direct impact on the stability or the activity of the target proteins they are attached to. In this mini review, we discuss the mechanisms that control the assembly and disassembly of branched chains by the enzymes of the ubiquitylation and deubiquitylation machinery. Existing knowledge regarding the activities of chain branching ubiquitin ligases and the deubiquitylases responsible for cleaving branched chains is summarized. We also highlight new findings concerning the formation of branched chains in response to small molecules that induce the degradation of otherwise stable proteins and examine the selective debranching of heterotypic chains by the proteasome-bound deubiquitylase UCH37.

FBXW7 tumor suppressor regulation by dualspecificity tyrosine-regulated kinase 2

FBXW7 is a member of the F-box protein family, which functions as the substrate recognition component of the SCF E3 ubiquitin ligase. FBXW7 is a main tumor suppressor due to its ability to control proteasome-mediated degradation of several oncoproteins such as c-Jun, c-Myc, Cyclin E1, mTOR, and Notch1-IC. FBXW7 inactivation in human cancers results from a somatic mutation or downregulation of its protein levels. This work describes a novel regulatory mechanism for FBXW7 dependent on the serine/threonine protein kinase DYRK2. We show that DYRK2 interacts with and phosphorylates FBXW7 resulting in its proteasome-mediated degradation. DYRK2-dependent FBXW7 destabilization is independent of its ubiquitin ligase activity. The functional analysis demonstrates the existence of DYRK2-dependent regulatory mechanisms for key FBXW7 substrates. Finally, we provide evidence indicating that DYRK2-dependent regulation of FBXW7 protein accumulation contributes to cytotoxic effects in response to chemotherapy agents such as Doxorubicin or Paclitaxel in colorectal cancer cell lines and to BET inhibitors in T-cell acute lymphoblastic leukemia cell lines. Altogether, this work reveals a new regulatory axis, DYRK2/FBXW7, which provides an understanding of the role of these two proteins in tumor progression and DNA damage responses.

FBXW7 attenuates tumor drug resistance and enhances the efficacy of immunotherapy

FBXW7 (F-box and WD repeat domain containing 7) is a critical subunit of the Skp1-Cullin1-F-box protein (SCF), acting as an E3 ubiquitin ligase by ubiquitinating targeted protein. Through degradation of its substrates, FBXW7 plays a pivotal role in drug resistance in tumor cells and shows the potential to rescue the sensitivity of cancer cells to drug treatment. This explains why patients with higher FBXW7 levels exhibit higher survival times and more favorable prognosis. Furthermore, FBXW7 has been demonstrated to enhance the efficacy of immunotherapy by targeting the degradation of specific proteins, as compared to the inactivated form of FBXW7. Additionally, other F-box proteins have also shown the ability to conquer drug resistance in certain cancers. Overall, this review aims to explore the function of FBXW7 and its specific effects on drug resistance in cancer cells.

Gold Nanoparticles Induced Size Dependent Cytotoxicity on Human Alveolar Adenocarcinoma Cells by Inhibiting the Ubiquitin Proteasome System

Gold nanoparticles (AuNPs) are widely used in biomedicine due to their remarkable therapeutic applications. However, little is known about their cytotoxic effects on the ubiquitin proteasome system (UPS). Herein, the cytotoxicity of different sizes of AuNPs (5, 10, and 80 nm) on the UPS was investigated with a particular focus on deubiquitinating enzymes (DUBs) such as ubiquitin-specific proteases (USP) and ubiquitin carboxyl-terminal hydrolases (UCHL-1) in human alveolar epithelial adenocarcinoma (A549). It was found that all sizes of AuNPs reduced the percentage of viable A549 cells and increased lactate dehydrogenase (LDH) release, measured using the MTT and LDH assays, respectively. Furthermore, the 5 nm AuNPs were found to exhibit greater cytotoxicity than the 10 and 80 nm AuNPs. In addition, apoptosis and necrosis were activated through reactive oxygen species (ROS) generation due to AuNPs exposure. The internalisation of AuNPs in A549 cells increased with increasing particle size (80 > 10 > 5 nm). Interestingly, the expression of USP7, USP8, USP10, and UCHL-1 was significantly (p < 0.001) downregulated upon treatment with 5-30 µg/mL of all the AuNPs sizes compared to control cells. Moreover, the inhibition of these proteins triggered mitochondrial-related apoptosis through the upregulation of poly (ADP-ribose) polymerase (PARP), caspase-3, and caspase-9. Collectively, these results indicate that AuNPs suppress the proliferation of A549 cells and can potentially be used as novel inhibitors of the proteasome.

E3 Ubiquitin Ligase TRIP12 Controls Exit from Mitosis via Positive Regulation of MCL-1 in Response to Taxol

Chemotherapy resistance is a major hurdle in cancer treatment. Taxol-based chemotherapy is widely used in the treatment of cancers including breast, ovarian, and pancreatic cancer. Loss of function of the tumor suppressor F-box WD-40 domain containing 7 (FBW7) mutations leads to the accumulation of its substrate MCL-1 which is associated with Taxol resistance in human cancers. We recently showed that E3 ubiquitin ligase TRIP12 is a negative regulator of FBW7 protein. In this study, we find that Taxol-induced mitotic block in cancer cells is partly controlled by TRIP12 via its positive regulation of MCL-1 protein. Genetic inhibition of TRIP12 accelerates MCL-1 protein degradation in mitosis. Notably, introducing double-point mutations in lysines 404/412 of FBW7 to arginine which makes it resistant to proteasomal degradation, leads to the sharp reduction of MCL-1 protein levels and sensitizes cancer cells to Taxol-induced cell death. Finally, TRIP12 deletion leads to enhanced mitotic arrest and cell death in an FBW7 and MCL-1 dependent manner in multiple cell lines including colorectal and ovarian cancer but not in breast cancer. Thus, the TRIP12/FBW7/MCL-1 axis may provide a therapeutic target to overcome Taxol-associated chemotherapy resistance in cancer.

Getting to the Root of Branched Ubiquitin Chains: A Review of Current Methods and Functions

Nearly 20 years since the first branched ubiquitin (Ub) chains were identified by mass spectrometry, our understanding of these chains and their function is still evolving. This is due to the limitations of classical Ub research techniques in identifying these chains and the vast complexity of potential branched chains. Considering only lysine or N-terminal methionine attachment sites, there are already 28 different possible branch points. Taking into account recently discovered ester-linked ubiquitination, branch points of more than two linkage types, and the higher-order chain structures within which branch points exist, the diversity of branched chains is nearly infinite. This review breaks down the complexity of these chains into their general functions, what we know so far about the different linkage combinations, branched chain-optimized methodologies, and the future perspectives of branched chain research.

A small Rho GTPase RAB25 with a potential role in chemotherapy resistance in pancreatic cancer

BACKGROUND

Pancreatic ductal adenocarcinoma (PDA) is one of the major human health challenges with minimal therapeutic benefits due to its late detection, and de novo - and acquired chemotherapy resistance.

OBJECTIVE

In this work we unravel the potential pro-survival role of RAB25 in pancreatic cancer chemotherapy resistance and aim to identify if RAB25 is a prognostic marker of patients' survival in PDA.

METHODS

We used RNA sequencing, shRNA mediated gene knockdown, BioGRID open repository of CRISPR screens (ORCS), GEPIA, kmplot.com, and cBioPortal.org databases to identify the role of RAB25 in PDA cell proliferation, chemotherapy response, expression in tumour versus normal tissues, and overall patients' survival.

RESULTS

RNA sequencing show Rab25 to be one of the top upregulated genes in gemcitabine resistance mouse PDA cells. Knockdown of Rab25 in these cells enhanced gemcitabine toxicity. In addition, re-analysis of previously published CRISPR/Cas9 data confirm RAB25 to be responsible for chemotherapy resistance in KRASG12D mutant human pancreatic cancer cell line. Finally, we used publicly available TCGA datasets and identify the upregulation of RAB25 in tumour tissues compared to the adjacent normal tissue, co-occurrence of KRASG12 mutations with RAB25 amplifications, and poor patients' survival in cohorts with higher mRNA expression of RAB25.

CONCLUSION

RAB25 expression is a prognostic marker for patient's survival and gemcitabine resistance in PDA.

Clonal relationship and alcohol consumption-associated mutational signature in synchronous hypopharyngeal tumours and oesophageal squamous cell carcinoma

BACKGROUND

The patients with dual oesophageal squamous cell carcinoma (ESCC) and hypopharyngeal cancer (HPC) have poor prognosis; their underlying genetic pathogenesis is unclear. We hypothesise that development of synchronous ESCC/HPC depends on multicentricity or independent origin, rather than multifocality due to local or lateral spreading.

METHOD

Multiple region whole-exome sequencing (M-WES) and clonality analysis were used to assess clonal relationship and spatial inter- or intra-tumour heterogeneity (ITH) in 62 tumour regions from eight dual ESCC/HPC and ten ESCC patients.

RESULTS

All synchronous ESCC/HPC patients had COSMIC 16 mutation signatures, compared to only 40% ESCC in the current study (p = 0.013) and public data set (n = 165, p = 0.003). This alcohol consumption-related mutation signature 16, commonly involved in multiple alcohol-related cancers, was significantly associated with drinking and alcohol metabolism-related ADH1B rs1229984. The mutational landscape and copy number profiles were completely distinct between the two primary tumours; clonality analysis further suggested the two primary tumours shared no or only one clone accompanying independent subclone evolution. M-WES strategy demonstrated higher sensitivity and accuracy for detection of mutational prevalence and the late branch mutations among different regions in the ESCC tumours, compared to traditional sequencing analysis based on single biopsy strategy. Patients with high ITH assessed by cancer cell fraction analysis after M-WES were significantly associated with both relapse and survival.

CONCLUSIONS

Our hypothesis-generating M-WES ITH assessment data have implications for prognostication. Collectively, our findings support multicentric independent clonal evolution, the field cancerisation theory, and suggest novel insights implicating an aetiologic role of alcohol metabolism in dual ESCC/HPC carcinogenesis.

Loss of the Fbw7 tumor suppressor rewires cholesterol metabolism in cancer cells leading to activation of the PI3K-AKT signalling axis

The sterol regulatory-element binding proteins (SREBPs) are transcription factors controlling cholesterol and fatty acid synthesis and metabolism. There are three SREBP proteins, SREBP1a, SREBP1c and SREBP2, with SREBP1a being the strongest transcription factor. The expression of SREBP1a is restricted to rapidly proliferating cells, including cancer cells. The SREBP proteins are translated as large, inactive precursors bound to the endoplasmic reticulum (ER) membranes. These precursors undergo a two-step cleavage process that releases the amino terminal domains of the proteins, which translocate to the nucleus and function as transcription factors. The nuclear forms of the SREBPs are rapidly degraded by the ubiquitin-proteasome system in a manner dependent on the Fbw7 ubiquitin ligase. Consequently, inactivation of Fbw7 results in the stabilization of active SREBP1 and SREBP2 and enhanced expression of target genes. We report that the inactivation of Fbw7 in cancer cells blocks the proteolytic maturation of SREBP2. The same is true in cells expressing a cancer-specific loss-of-function Fbw7 protein. Interestingly, the activation of SREBP2 is restored in response to cholesterol depletion, suggesting that Fbw7-deficient cells accumulate cholesterol. Importantly, inactivation of SREBP1 in Fbw7-deficient cells also restores the cholesterol-dependent regulation of SREBP2, suggesting that the stabilization of active SREBP1 molecules could be responsible for the blunted activation of SREBP2 in Fbw7-deficient cancer cells. We suggest that this could be an important negative feedback loop in cancer cells with Fbw7 loss-of-function mutations to protect these cells from the accumulation of toxic levels of cholesterol and/or cholesterol metabolites. Surprisingly, we also found that the inactivation of Fbw7 resulted in the activation of AKT. Importantly, the activation of AKT was dependent on SREBP1 and on the accumulation of cholesterol. Thus, we suggest that the loss of Fbw7 rewires lipid metabolism in cancer cells to support cell proliferation and survival.

Clinicopathological and prognostic significance of speckle-type POZ protein in cancers: a systematic review and meta-analysis

BACKGROUND

Controversial findings have been reported in the impact of speckle-type POZ protein (SPOP) on clinicopathological features and prognosis in diverse cancers. We conducted this meta-analysis to confirm whether SPOP was an effective biomarker to predict clinical stage, cancer differentiation and survival.

METHODS

We searched studies published before June 2021 through Medline, Embase, the Cochrane library register of controlled trials and Wanfang databases. The corrections of SPOP expression with expression disparity, tumor differentiation, clinical stage and survival were analyzed.

RESULTS

Our meta-analysis found that higher expression of SPOP was significantly associated with earlier clinical stage, well differentiation and better overall survival. Subgroup analysis showed that the SPOP expression of adjacent tissue was significantly higher than that in cancer tissues of prostate and liver. However, renal cancer presented improved expression of SPOP in cancer tissue.

CONCLUSIONS

SPOP has the potential function to act as a novel and effective biomarker for cancer diagnosis and prognostic stratification.