Identification of the SUMO E3 ligase PIAS1 as a potential survival biomarker in breast cancer

Application and prospect of organoid technology in breast cancer

Breast cancer is the most common malignant tumor in women. Due to the high heterogeneity of breast cancer cells, traditional in vitro research models still have major limitations. Therefore, it is urgent to establish an experimental model that can accurately simulate the characteristics of human breast cancer. Breast cancer organoid technology emerged as the times required, that is, to construct tissue analogs with organ characteristics by using a patient's tumor tissue through 3D culture in vitro. Since the breast cancer organoid can fully preserve the histology and genetic characteristics of the original tumor, it provides a reliable model for preclinical drug screening, establishment of breast cancer organoid biobanks, research into the mechanisms of tumor development, and determination of cancer targets. It has promoted personalized treatment for clinical breast cancer patients. This article mainly focuses on recent research progress and applications of organoid technology in breast cancer, discussing the current limitations and prospects of breast cancer organoid technology.

PIAS family in cancer: from basic mechanisms to clinical applications

Protein inhibitors of activated STATs (PIAS) are proteins for cytokine signaling that activate activator-mediated gene transcription. These proteins, as versatile cellular regulators, have been described as regulators of approximately 60 proteins. Dysregulation of PIAS is associated with inappropriate gene expression that promotes oncogenic signaling in multiple cancers. Multiple lines of evidence have revealed that PIAS family members show modulated expressions in cancer cells. Most frequently reported PIAS family members in cancer development are PIAS1 and PIAS3. SUMOylation as post-translational modifier regulates several cellular machineries. PIAS proteins as SUMO E3 ligase factor promotes SUMOylation of transcription factors tangled cancer cells for survival, proliferation, and differentiation. Attenuated PIAS-mediated SUMOylation mechanism is involved in tumorigenesis. This review article provides the PIAS/SUMO role in the modulation of transcriptional factor control, provides brief update on their antagonistic function in different cancer types with particular focus on PIAS proteins as a bonafide therapeutic target to inhibit STAT pathway in cancers, and summarizes natural activators that may have the ability to cure cancer.

Prevalence and Prognostic Significance of PIK3CA Mutation and CNV Status and Phosphorylated AKT Expression in Patients With Cervical Cancer Treated With Primary Surgery

Currently, there are limited and conflicting reports on the prognostic utility of PIK3CA and associated pathway markers for cervical cancers treated with primary surgical management. Moreover, current studies are lacking complete characterization of adjuvant treatment with RT and/or chemotherapy. We aimed to document the prevalence, clinicopathologic, adjuvant treatment details, and prognostic value of PI3K/AKT pathway mutations and copy number variation and phosphorylated AKT status in patients with cervical cancers treated with primary surgery. A clinicopathologic review was performed on a retrospective cohort of 185 patients with cervical cancer, treated with primary surgery at a single tertiary institution. Next-generation sequencing and digital PCR was used to determine PI3K/AKT pathway mutational status and PIK3CA copy number variation, respectively, and fluorescent immunohistochemistry measured phosphorylated AKT expression. In all, 179 of 185 (96.8%) of tumors were successfully sequenced; 48 (26.8%) were positive for PI3K/AKT pathway mutations-the majority (n=37, 77.1%) PIK3CA mutations. PIK3CA mutation was associated with pathologically positive lymph nodes [12 (32%) vs. 22 (16%); P =0.022] and indication for postoperative chemoradiotherapy [17 (45.9%) vs. 32 (22.5%); P =0.004]. On multivariable analysis, PIK3CA status was not associated with overall survival ( P =0.103) or progression-free survival ( P =0.240) at 5 yrs, nor was PIK3CA copy number variation status. phosphorylated AKT ≤ median significantly predicted for progression-free survival [multivariable hazard ratio 0.39 (0.17-0.89; P =0.025)] but not overall survival ( P =0.087). The correlation of PIK3CA with pathologic positive lymph node status yet lack of association with survival outcomes may be due to the use of adjuvant postoperative therapy. PIK3CA assessment before radical hysterectomy may help identify patients with a higher risk of node-positive disease.

Exploring Potential Epigenetic Biomarkers for Colorectal Cancer Metastasis

Metastatic progression is a complex, multistep process and the leading cause of cancer mortality. There is growing evidence that emphasises the significance of epigenetic modification, specifically DNA methylation and histone modifications, in influencing colorectal (CRC) metastasis. Epigenetic modifications influence the expression of genes involved in various cellular processes, including the pathways associated with metastasis. These modifications could contribute to metastatic progression by enhancing oncogenes and silencing tumour suppressor genes. Moreover, specific epigenetic alterations enable cancer cells to acquire invasive and metastatic characteristics by altering cell adhesion, migration, and invasion-related pathways. Exploring the involvement of DNA methylation and histone modification is crucial for identifying biomarkers that impact cancer prediction for metastasis in CRC. This review provides a summary of the potential epigenetic biomarkers associated with metastasis in CRC, particularly DNA methylation and histone modifications, and examines the pathways associated with these biomarkers.

Human Post-Translational SUMOylation Modification of SARS-CoV-2 Nucleocapsid Protein Enhances Its Interaction Affinity with Itself and Plays a Critical Role in Its Nuclear Translocation

Viruses, such as Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), infect hosts and take advantage of host cellular machinery for genome replication and new virion production. Identifying and elucidating host pathways for viral infection is critical for understanding the development of the viral life cycle and novel therapeutics. The SARS-CoV-2 N protein is critical for viral RNA (vRNA) genome packaging in new virion formation. Using our quantitative Förster energy transfer/Mass spectrometry (qFRET/MS) coupled method and immunofluorescence imaging, we identified three SUMOylation sites of the SARS-CoV-2 N protein. We found that (1) Small Ubiquitin-like modifier (SUMO) modification in Nucleocapsid (N) protein interaction affinity increased, leading to enhanced oligomerization of the N protein; (2) one of the identified SUMOylation sites, K65, is critical for its nuclear translocation. These results suggest that the host human SUMOylation pathway may be critical for N protein functions in viral replication and pathology in vivo. Thus, blocking essential host pathways could provide a novel strategy for future anti-viral therapeutics development, such as for SARS-CoV-2 and other viruses.

Sumoylated SnoN interacts with HDAC1 and p300/CBP to regulate EMT-associated phenotypes in mammary organoids

Protein post-translational modification by the small ubiquitin-like modifier (SUMO) regulates the stability, subcellular localization, and interactions of protein substrates with consequences on cellular responses including epithelial-mesenchymal transition (EMT). Transforming growth factor beta (TGFβ) is a potent inducer of EMT with implications for cancer invasion and metastasis. The transcriptional coregulator SnoN suppresses TGFβ-induced EMT-associated responses in a sumoylation-dependent manner, but the underlying mechanisms have remained largely unknown. Here, we find that sumoylation promotes the interaction of SnoN with the epigenetic regulators histone deacetylase 1 (HDAC1) and histone acetylase p300 in epithelial cells. In gain and loss of function studies, HDAC1 suppresses, whereas p300 promotes, TGFβ-induced morphogenetic changes associated with EMT-related events in three-dimensional multicellular organoids derived from mammary epithelial cells or carcinomas. These findings suggest that sumoylated SnoN acts via the regulation of histone acetylation to modulate EMT-related effects in breast cell organoids. Our study may facilitate the discovery of new biomarkers and therapeutics in breast cancer and other epithelial cell-derived cancers.

Methylation Levels in the Promoter Region of FHIT and PIAS1 Genes Associated with Mastitis Resistance in Xinjiang Brown Cattle

Mastitis causes serious economic losses in the dairy industry, but there are no effective treatments or preventive measures. In this study, the ZRANB3, PIAS1, ACTR3, LPCAT2, MGAT5, and SLC37A2 genes in Xinjiang brown cattle, which are associated with mastitis resistance, were identified using a GWAS. Pyrosequencing analysis showed that the promoter methylation levels of the FHIT and PIAS1 genes in the mastitis group were higher and lower, respectively, than those in the healthy group (65.97 ± 19.82% and 58.00 ± 23.52%). However, the methylation level of the PIAS1 gene promoter region in the mastitis group was lower than that in the healthy group (11.48 ± 4.12% and 12.17 ± 4.25%). Meanwhile, the methylation levels of CpG3, CpG5, CpG8, and CpG15 in the promoter region of the FHIT and PIAS1 genes in the mastitis group were significantly higher than those in the healthy group (p < 0.01), respectively. RT-qPCR showed that the expression levels of the FHIT and PIAS1 genes were significantly higher in the healthy group than those in the mastitis group (p < 0.01). Correlation analysis showed that the promoter methylation level of the FHIT gene was negatively correlated with its expression. Hence, increased methylation in the promoter of the FHIT gene reduces the mastitis resistance in Xinjiang brown cattle. Finally, this study provides a reference for the molecular-marker-assisted selection of mastitis resistance in dairy cattle.

Investigation of molecular mechanisms underlying JAK/STAT signaling pathway in HPV-induced cervical carcinogenesis using 'omics' approach

The precise mechanism of action of Janus Kinases (JAK)/Signal Transducer and activator of Transcription (STAT) signaling in human papillomavirus (HPV)-associated cervical cancer (CaCx) is poorly defined. The present study dissected the underlying components of JAK/STAT signaling in HPV-positive cervical neoplasms. Whole transcriptome profile of CaCx cohort from TCGA database revealed elevated STAT3 and its impact on CaCx patients' survival. Using the RT² Profiler PCR Array, we analyzed 84 genes of interest associated with JAK/STAT signaling in mRNA derived from HPV-negative and HPV-positive cervical lesions which revealed 21 differentially expressed genes (DEGs). Analyses of DEGs using the Database for Annotation, Visualization and Integrated Discovery tool indicated maximum genes enriched in immune response and negative regulation of apoptotic process. Protein-protein network analysis indicated IL4, STAT5A, STAT4, and JAK3 to be the key genes in the interaction network. Further, 7 key DEGs (IL4R, IRF1, EGFR, OAS1, PIAS1, STAT4, and STAT5A) were validated in TCGA cohort using R2 platform. These genes were differentially expressed among HPV-positive cervical tissues and their correlation with STAT3 was established. EGFR and IL4R showed a comparatively strong correlation with STAT3 that supports their involvement in pathogenesis of CaCx. Finally, the Kaplan-Meier analysis established the prognostic association of the key DEGs, in CaCx cohort. The STAT3 and associated key genes discovered from our study establish a strong pathogenic role of JAK/STAT3 pathway in HPV-mediated cervical carcinogenesis.

The prognostic impact of PD-L1 and CD8 expression in anal cancer patients treated with chemoradiotherapy

Background

Programmed death-ligand 1 (PD-L1) expression has been shown to be prognostic in many cancer types and used in consideration of checkpoint inhibitor immunotherapy. However, there are very limited and conflicting data on the prognostic impact of PD-L1 in patients with anal squamous cell carcinoma (ASCC). The objectives of this study were to measure the expression of PD-L1 and CD8 in patients with ASCC treated with radical chemoradiotherapy (CRT) and to correlate tumor expression with progression-free survival (PFS) and overall survival (OS).

Methods

Ninety-nine patients with ASCC treated with primary CRT at two tertiary care cancer centers between 2000 and 2013, with available pre-treatment tumors, were included. Tissue microarrays (TMAs) from pre-treatment tumor specimens were stained for PD-L1 and CD8. PD-L1 expression in the tumor and stroma was quantified using HALO image analysis software, and results were interpreted using quantitative methods. The density of CD8 cells within the tumor was interpreted by a trained pathologist semi-quantitatively, using a 0-4 scoring system. Kaplan-Meier analysis with log-rank was used to determine the significance in the association of tumor markers with PFS and OS. Cox multivariate analysis was used to explore independent predictors of PFS and OS.

Results

Of the 99 patients, 63 (64%) had sufficient tumor samples available for full analysis. CD8 high status was documented in 32 of 63 (50.8%) % of cases. PD-L1 expression was positive in 88.9% of cases. Approximately half the patients had tumor PD-L1 ≥ 5%. Patients with tumor PD-L1 ≥ 5% had better OS vs those with lower expression, HR=0.32 (95% CI 0.11-0.87), p=0.027; 10 years OS: 84% for tumor PD-L1 ≥ 5% vs 49% for PD-L1 < 5%. PD-L1 expression was not associated with PFS. On multivariate analysis, tumor PD-L1 ≥ 5% showed a trend to statistical significance for better OS, HR=0.55 (95% CI 0.12- 1.00), p=0.052.

Conclusions

Tumor PD-L1≥5% is associated with OS in patients with ASCC treated with CRT. PD-L1 expression status using this unique cut-point warrants further validation for prognostication in patients with this disease. Future studies are required to determine the benefit of alternative treatment strategies based on PD-L1 status.

Cancer-Associated Dysregulation of Sumo Regulators: Proteases and Ligases

SUMOylation is a post-translational modification that has emerged in recent decades as a mechanism involved in controlling diverse physiological processes and that is essential in vertebrates. The SUMO pathway is regulated by several enzymes, proteases and ligases being the main actors involved in the control of sumoylation of specific targets. Dysregulation of the expression, localization and function of these enzymes produces physiological changes that can lead to the appearance of different types of cancer, depending on the enzymes and target proteins involved. Among the most studied proteases and ligases, those of the SENP and PIAS families stand out, respectively. While the proteases involved in this pathway have specific SUMO activity, the ligases may have additional functions unrelated to sumoylation, which makes it more difficult to study their SUMO-associated role in cancer process. In this review we update the knowledge and advances in relation to the impact of dysregulation of SUMO proteases and ligases in cancer initiation and progression.

SUMOylation and NEDDylation in Primary and Metastatic Cancers to Bone

Post-translational modifications comprise series of enzymatically-driven chemical modifications, virtually involving the entire cell proteome, that affect the fate of a target protein and, in turn, cell activity. Different classes of modifications can be established ranging from phosphorylation, glycosylation, ubiquitination, acetylation, methylation, lipidation and their inverse reactions. Among these, SUMOylation and NEDDylation are ubiquitin-like multi-enzymatic processes that determine the bound of SUMOs and NEDD8 labels, respectively, on defined amino acidic residues of a specific protein and regulate protein function. As fate-determinants of several effectors and mediators, SUMOylation and NEDDylation play relevant roles in many aspects of tumor cell biology. Bone represents a preferential site of metastasis for solid tumors (e.g., breast and prostate cancers) and the primary site of primitive tumors (e.g., osteosarcoma, chondrosarcoma). Deregulation of SUMOylation and NEDDylation affects different aspects of neoplastic transformation and evolution such as epithelial-mesenchymal transition, adaptation to hypoxia, expression and action of tumor suppressors and oncogenic mediators, and drug resistance. Thereby, they represent potential therapeutic targets. This narrative review aims at describing the involvement and regulation of SUMOylation and NEDDylation in tumor biology, with a specific focus on primary and secondary bone tumors, and to summarize and highlight their potentiality in diagnostics and therapeutic strategies.

The Role of SUMO E3 Ligases in Signaling Pathway of Cancer Cells

Small ubiquitin-like modifier (SUMO)ylation is a reversible post-translational modification that plays a crucial role in numerous aspects of cell physiology, including cell cycle regulation, DNA damage repair, and protein trafficking and turnover, which are of importance for cell homeostasis. Mechanistically, SUMOylation is a sequential multi-enzymatic process where SUMO E3 ligases recruit substrates and accelerate the transfer of SUMO onto targets, modulating their interactions, localization, activity, or stability. Accumulating evidence highlights the critical role of dysregulated SUMO E3 ligases in processes associated with the occurrence and development of cancers. In the present review, we summarize the SUMO E3 ligases, in particular, the novel ones recently identified, and discuss their regulatory roles in cancer pathogenesis.

Mnt Represses Epithelial Identity To Promote Epithelial-to-Mesenchymal Transition

The multistep process of epithelial-to-mesenchymal transition (EMT), whereby static epithelial cells become migratory mesenchymal cells, plays a critical role during various developmental contexts, wound healing, and pathological conditions such as cancer metastasis. Despite the established function of basic helix-loop-helix (bHLH) transcription factors (TFs) in cell fate determination, only a few have been examined for their role in EMT. Here, using transcriptome analysis of distinct stages during stepwise progression of transforming growth factor beta (TGFβ)-induced EMT in mammary epithelial cells, we revealed distinct categories of bHLH TFs that show differential expression kinetics during EMT. Using a short interfering RNA-mediated functional screen for bHLH TFs during EMT, we found Max network transcription repressor (MNT) to be essential for EMT in mammary epithelial cells. We show that the depletion of MNT blocks TGFβ-induced morphological changes during EMT, and this is accompanied by derepression of a large number of epithelial genes. We show that MNT mediates the repression of epithelial identity genes during EMT by recruiting HDAC1 and mediating the loss of H3K27ac and chromatin accessibility. Lastly, we show that MNT is expressed at higher levels in EMT-High breast cancer cells and is required for their migration. Taken together, these findings establish MNT as a critical regulator of cell fate changes during mammary EMT. IMPORTANCE The bHLH TF Mnt promotes epithelial to mesenchymal transition through epigenetic repression of the epithelial gene expression program.

Therapeutic Potential of Targeting the SUMO Pathway in Cancer

SUMOylation is a dynamic and reversible post-translational modification, characterized more than 20 years ago, that regulates protein function at multiple levels. Key oncoproteins and tumor suppressors are SUMO substrates. In addition to alterations in SUMO pathway activity due to conditions typically present in cancer, such as hypoxia, the SUMO machinery components are deregulated at the genomic level in cancer. The delicate balance between SUMOylation and deSUMOylation is regulated by SENP enzymes possessing SUMO-deconjugation activity. Dysregulation of SUMO machinery components can disrupt the balance of SUMOylation, contributing to the tumorigenesis and drug resistance of various cancers in a context-dependent manner. Many molecular mechanisms relevant to the pathogenesis of specific cancers involve SUMO, highlighting the potential relevance of SUMO machinery components as therapeutic targets. Recent advances in the development of inhibitors targeting SUMOylation and deSUMOylation permit evaluation of the therapeutic potential of targeting the SUMO pathway in cancer. Finally, the first drug inhibiting SUMO pathway, TAK-981, is currently also being evaluated in clinical trials in cancer patients. Intriguingly, the inhibition of SUMOylation may also have the potential to activate the anti-tumor immune response. Here, we comprehensively and systematically review the recent developments in understanding the role of SUMOylation in cancer and specifically focus on elaborating the scientific rationale of targeting the SUMO pathway in different cancers.

SUMOylation Wrestles With the Occurrence and Development of Breast Cancer

Breast cancer has the highest incidence among cancers and is the most frequent cause of death in women worldwide. The detailed mechanism of the pathogenesis of breast cancer has not been fully elucidated, and there remains a lack of effective treatment methods for the disease. SUMOylation covalently conjugates a large amount of cellular proteins, and affects their cellular localization and biological activity to participate in numerous cellular processes. SUMOylation is an important process and imbalance of SUMOylation results in the progression of human diseases. Increasing evidence shows that numerous SUMOylated proteins are involved in the occurrence and development of breast cancer. This review summarizes a series of studies on protein SUMOylation in breast cancer in recent years. The study of SUMOylated proteins provides a comprehensive understanding of the pathophysiology of breast cancer and provides evolving therapeutic strategies for the treatment of breast cancer.

miR-182-5p and miR-96-5p Target PIAS1 and Mediate the Negative Feedback Regulatory Loop between PIAS1 and STAT3 in Endometrial Cancer

The expressions and roles of protein inhibitor of activated STAT (PIAS) proteins, a group of proteins with STAT inhibition and SUMOylation E3 ligase activity, are rarely revealed in endometrial cancer (EC). In this study, we analyzed the expressions of PIASs and their relationships with clinical features by mining online data through web servers, including UALCAN and Gene Expression Profiling Interactive Analysis (GEPIA) in EC. The expressions of PIASs in EC tissues were further validated by immunohistochemistry (IHC). The online analyses revealed only PIAS1 was consistently downregulated both at mRNA and protein level in EC, which was validated by the IHC. Subsequently, the mechanism of PIAS1 downregulation was explored with online tools like UALCAN, cBioPortal, LinkedOmics, and the Encyclopedia of RNA Interactomes (ENCORI). The results indicated that the mutation rate of PIAS1 was extremely low and not associated with PIAS1 expression. The promoter methylation level of PIAS1 was comparable between normal and EC tissues. miR-182-5p and miR-96-5p with negative association with PIAS1 in EC were predicted to target PIAS1. Dual luciferase reporter assay confirmed miR-182-5p and miR-96-5p could target PIAS1 in EC. MiR-182-5p and miR-96-5p inhibitors could upregulate PIAS1 in EC cells. Moreover, ectopic PIAS1 expression and STAT3 inhibitor treatment significantly inhibited STAT3's activity and the levels of miR-182-5p and miR-96-5p in EC cells. Collectively, our findings revealed PIAS1 was downregulated in EC, which was caused by upregulation of miR-182-5p and miR-96-5p, and PIAS1 downregulation further activated STAT3 and increased the expression of miR-182-5p and miR-96-5p, confirming miR-182-5p and miR-96-5p mediated the negative feedback regulatory loop between PIAS1 and STAT3 in EC.

An immunohistochemical panel of three small ubiquitin-like modifier genes predicts outcomes of patients with triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) is a highly heterogeneous and aggressive disease. Developing new candidate biomarkers for chemotherapy response and possible therapeutic targets has become an urgent clinical need. Small ubiquitin-like modifiers (SUMOs) mediate post-translational modifications (SUMOylation) has been shown to be involved in numerous biological processes. However, the role of SUMOylation in TNBC has yet to be elucidated.

Method

The mRNA expression of SUMO1/2/3 was analyzed by the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus database (GEO) databases (N=412). We also evaluated the SUMO1/2/3 protein expression in 212 TNBC patients using immunohistochemical (IHC) staining method. A classifier with Least absolute shrinkage and selection operator (LASSO) Cox regression model was then built based on the associations between the expression of SUMO1/2/3 proteins and the disease-free survival (DFS) of TNBC patients.

Results

Elevated SUMO1/2/3 levels were indicated to be associated with a poorer overall survival (OS) and DFS for TNBC patients. With the LASSO model, we built a classifier based on the IHC scores of SUMO1/2/3 proteins and named it the 'SB classifier'. Patients with SB classifier-defined high score were found to have an unfavorable response to chemotherapy [hazard ratio (HR) 4.04, 95% confidence interval (CI): 2.14-7.63; P<0.0001]. A nomogram was then developed to identify which patients might benefit from chemotherapy. Finally, our results also suggested that the activation of SUMOylation pathway in TNBC might be induced by MYC signaling.

Conclusions

We constructed a reliable prognostic and predictive tool for TNBC patients treated with chemotherapy, which could facilitate individualized counseling and management.

Whole genome sequence analysis of pulmonary function and COPD in 19,996 multi-ethnic participants

Chronic obstructive pulmonary disease (COPD), diagnosed by reduced lung function, is a leading cause of morbidity and mortality. We performed whole genome sequence (WGS) analysis of lung function and COPD in a multi-ethnic sample of 11,497 participants from population- and family-based studies, and 8499 individuals from COPD-enriched studies in the NHLBI Trans-Omics for Precision Medicine (TOPMed) Program. We identify at genome-wide significance 10 known GWAS loci and 22 distinct, previously unreported loci, including two common variant signals from stratified analysis of African Americans. Four novel common variants within the regions of PIAS1, RGN (two variants) and FTO show evidence of replication in the UK Biobank (European ancestry n ~ 320,000), while colocalization analyses leveraging multi-omic data from GTEx and TOPMed identify potential molecular mechanisms underlying four of the 22 novel loci. Our study demonstrates the value of performing WGS analyses and multi-omic follow-up in cohorts of diverse ancestry.

Regulation of epithelial-mesenchymal transition and organoid morphogenesis by a novel TGFβ-TCF7L2 isoform-specific signaling pathway

Alternative splicing contributes to diversification of gene function, yet consequences of splicing on functions of specific gene products is poorly understood. The major transcription factor TCF7L2 undergoes alternative splicing but the biological significance of TCF7L2 isoforms has remained largely to be elucidated. Here, we find that the TCF7L2 E-isoforms maintain, whereas the M and S isoforms disrupt morphogenesis of 3D-epithelial cell-derived organoids via regulation of epithelial-mesenchymal transition (EMT). Remarkably, TCF7L2E2 antagonizes, whereas TCF7L2M2/S2 promotes EMT-like effects in epithelial cells induced by transforming growth factor beta (TGFβ) signaling. In addition, we find TGFβ signaling reduces the proportion of TCF7L2E to TCF7L2M/S protein in cells undergoing EMT. We also find that TCF7L2 operates via TGFβ-Smad3 signaling to regulate EMT. Collectively, our findings unveil novel isoform-specific functions for the major transcription factor TCF7L2 and provide novel links between TCF7L2 and TGFβ signaling in the control of EMT-like responses and epithelial tissue morphogenesis.

PIAS1 and TIF1γ collaborate to promote SnoN SUMOylation and suppression of epithelial-mesenchymal transition

SUMO E3 ligases specify protein substrates for SUMOylation. The SUMO E3 ligases PIAS1 and TIF1γ target the transcriptional regulator SnoN for SUMOylation leading to suppression of epithelial-mesenchymal transition (EMT). Whether and how TIF1γ and PIAS1 might coordinate SnoN SUMOylation and regulation of EMT remained unknown. Here, we reveal that SnoN associates simultaneously with both TIF1γ and PIAS1, leading to a trimeric protein complex. Hence, PIAS1 and TIF1γ collaborate to promote the SUMOylation of SnoN. Importantly, loss of function studies of PIAS1 and TIF1γ suggest that these E3 ligases act in an interdependent manner to suppress EMT of breast cell-derived tissue organoids. Collectively, our findings unveil a novel mechanism by which SUMO E3 ligases coordinate substrate SUMOylation with biological implications.

PIK3CA mutation and CNV status and post-chemoradiotherapy survival in patients with cervical cancer

PURPOSE

This study aimed to describe the prognostic value of PI3K/AKT pathway mutations in a large cohort of patients with cervical cancer.

EXPERIMENTAL DESIGN

Patients with pre-treatment archival specimens, diagnosed with FIGO stages IB-IVA cervical cancer between 1998 and 2014 and treated with radical, curative intent chemoradiotherapy (CRT) at a single center were identified. Mutational status was determined by next generation sequencing and PIK3CA copy number (CNV) was assessed by digital PCR.

RESULTS

190 patients with available pre-treatment tumor specimens were identified. Median OS and PFS were 57.4 and 46.0 months, respectively. A total of 161 tumors were successfully sequenced; 60 (37.3%) had PI3K/AKT pathway mutations, with 50 (30.1%) having PIK3CA hotspot mutations. PIK3CA CNV gain was noted in 79 (59.2%) of the 154 successfully analyzed. On univariate analysis, PIK3CA mutation was associated with poor OS (HR 1.73; 95% CI: 1.03-2.92; p = .037) but not PFS (HR 1.38; 0.84-2.28; p = .204). Absence of any PI3K/AKT pathway mutation was associated with improved OS (HR 1.68; 1.01-2.81; p = .046) but not PFS (HR 1.50; 0.93-2.43; p = .202). Associations were not maintained when adjusting for clinical factors. On univariate analysis, PIK3CA mutation positive, CNV normal tumors were associated with poorer OS (HR 2.55; 1.18-5.50; p = .017) and trend to worse PFS (HR 1.87; 0.90-3.83; p = .094) when compared to those with CNV gain and wildtype PIK3CA.

CONCLUSIONS

PI3K/AKT pathway mutations are common in cervical cancer. Consideration of PIK3CA mutational status with CNV status may be important in predicting outcome in cervical cancer patients.

Novel Variants of ELP2 and PIAS1 in the Interferon Gamma Signaling Pathway Are Associated with Non-Small Cell Lung Cancer Survival

BACKGROUND

IFNγ is a pleiotropic cytokine that plays critical immunomodulatory roles in intercellular communication in innate and adaptive immune responses. Despite recognition of IFNγ signaling effects on host defense against viral infection and its utility in immunotherapy and tumor progression, the roles of genetic variants of the IFNγ signaling pathway genes in survival of patients with cancer remain unknown.

METHODS

We used a discovery genotyping dataset from the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (n = 1,185) and a replication genotyping dataset from the Harvard Lung Cancer Susceptibility Study (n = 984) to evaluate associations between 14,553 genetic variants in 150 IFNγ pathway genes and survival of non-small cell lung cancer (NSCLC).

RESULTS

The combined analysis identified two independent potentially functional SNPs, ELP2 rs7242481G>A and PIAS1 rs1049493T>C, to be significantly associated with NSCLC survival, with a combined HR of 0.85 (95% confidence interval, 0.78-0.92; P < 0.0001) and 0.87 (0.81-0.93; P < 0.0001), respectively. Expression quantitative trait loci analyses showed that the survival-associated ELP2 rs7242481A allele was significantly associated with increased mRNA expression levels of elongator acetyltransferase complex subunit 2 (ELP2) in 373 lymphoblastoid cell lines and 369 whole-blood samples. The PIAS1 rs1049493C allele was significantly associated with decreased mRNA expression levels of PIAS1 in 383 normal lung tissues and 369 whole-blood samples.

CONCLUSIONS

Genetic variants of IFNγ signaling genes are potential prognostic markers for NSCLC survival, likely through modulating the expression of key genes involved in host immune response.

IMPACT

Once validated, these variants could be useful predictors of NSCLC survival.

The prevalence and prognostic significance of estrogen receptor beta expression in non-small cell lung cancer

Background

Estrogen receptor beta (ERβ) is the predominant estrogen receptor (ER) expressed in non-small cell lung cancer (NSCLC); however, due to methodological disparities among prior studies, the prognostic value of ERβ expression in NSCLC remains unclear. Our objective was to apply improved detection and analysis techniques to assess the prognostic value of ERβ expression in NSCLC.

Methods

A tissue microarray (TMA) was used which contained resected and biopsy specimens from 299 patients diagnosed at a single center with stages I-IV NSCLC. Sections of this array were stained using high-sensitivity fluorescence immunohistochemistry, with the well-validated PPG5/10 monoclonal antibody. Digital images of the stained array slides were analyzed using software-based image analysis, which reported ERβ expression as a continuous variable in different subcellular domains.

Results

There were no differences in ERβ expression between male and female patients. High expression of ERβ was not a prognostic factor, but was significantly associated with stage IV disease in both tumor and stroma (P<0.001). In multivariable analysis, a high nuclear/cytoplasmic (N/C) ratio of ERβ expression was significantly associated with shorter overall survival, based on expression in the tumor [hazard ratio (HR): 1.65; 95% confidence interval (CI): 1.25-2.19; P<0.001] and in the stroma (HR: 1.57; 95% CI: 1.16-2.12; P=0.003).

Conclusions

These results suggest that subcellular localization of ERβ, but not absolute expression, is a prognostic factor in NSCLC.

Progress in the application of organoids to breast cancer research

Breast cancer is the most common cancer diagnosed in women. Breast cancer research is currently based mainly on animal models and traditional cell culture. However, the inherent species gap between humans and animals, as well as differences in organization between organs and cells, limits research advances. The breast cancer organoid can reproduce many of the key features of human breast cancer, thereby providing a new platform for investigating the mechanisms underlying the development, progression, metastasis and drug resistance of breast cancer. The application of organoid technology can also promote drug discovery and the design of individualized treatment strategies. Here, we discuss the latest advances in the use of organoid technology for breast cancer research.

The implication of the SUMOylation pathway in breast cancer pathogenesis and treatment

Breast cancer is the most commonly diagnosed malignancy in woman worldwide, and is the second most common cause of death in developed countries. The transformation of a normal cell into a malignant derivate requires the acquisition of diverse genomic and proteomic changes, including enzymatic post-translational modifications (PTMs) on key proteins encompassing critical cell signaling events. PTMs occur on proteins after translation, and regulate several aspects of proteins activity, including their localization, activation and turnover. Deregulation of PTMs can potentially lead to tumorigenesis, and several de-regulated PTM pathways contribute to abnormal cell proliferation during breast tumorigenesis. SUMOylation is a PTM that plays a pivotal role in numerous aspects of cell physiology, including cell cycle regulation, protein trafficking and turnover, and DNA damage repair. Consistently with this, the deregulation of the SUMO pathway is observed in different human pathologies, including breast cancer. In this review we will describe the role of SUMOylation in breast tumorigenesis and its implication for breast cancer therapy.

Ubiquitin, SUMO, and Nedd8 as Therapeutic Targets in Cancer

Ubiquitin defines a family of approximately 20 peptidic posttranslational modifiers collectively called the Ubiquitin-like (UbLs). They are conjugated to thousands of proteins, modifying their function and fate in many ways. Dysregulation of these modifications has been implicated in a variety of pathologies, in particular cancer. Ubiquitin, SUMO (-1 to -3), and Nedd8 are the best-characterized UbLs. They have been involved in the regulation of the activity and/or the stability of diverse components of various oncogenic or tumor suppressor pathways. Moreover, the dysregulation of enzymes responsible for their conjugation/deconjugation has also been associated with tumorigenesis and cancer resistance to therapies. The UbL system therefore constitutes an attractive target for developing novel anticancer therapeutic strategies. Here, we review the roles and dysregulations of Ubiquitin, SUMO, and Nedd8 pathways in tumorigenesis, as well as recent advances in the identification of small molecules targeting their conjugating machineries for potential application in the fight against cancer.

PIAS1 is not suitable as a urothelial carcinoma biomarker protein and pharmacological target

Urothelial cancer (UC) is one of the most common cancers in Europe and is also one of the costliest to treat. When first line therapies show initial success, around 50% of cancers relapse and proceed to metastasis. In this study we assessed the Protein inhibitor of activated signal transducers and activators of transcription (PIAS)1 as a potential therapeutic target in urothelial cancer. PIAS1 is a key regulator of STAT1 signalling and may be implicated in carcinogenesis. In contrast to other cancer types PIAS1 protein expression is not significantly different in malignant areas of UC specimens compared to non-malignant tissue. In addition, we found that down-regulation and overexpression of PIAS1 had no effect on the viability or colony forming ability of tested cell lines. Whilst other studies of PIAS1 suggest an important biological role in cancer, this study shows that PIAS1 has no influence on reducing the cytotoxic effects of Cisplatin or cell recovery after DNA damage induced by irradiation. Taken together, these in vitro data demonstrate that PIAS1 is not a promising therapeutic target in UC cancer as previously shown in different entities such as prostate cancer (PCa).

Recombinant human PRG4 (rhPRG4) suppresses breast cancer cell invasion by inhibiting TGFβ-Hyaluronan-CD44 signalling pathway

Metastasis is the major cause of cancer-related morbidity and mortality. The ability of cancer cells to become invasive and migratory contribute significantly to metastatic growth, which necessitates the identification of novel anti-migratory and anti-invasive therapeutic approaches. Proteoglycan 4 (PRG4), a mucin-like glycoprotein, contributes to joint synovial homeostasis through its friction-reducing and anti-adhesive properties. Adhesion to surrounding extracellular matrix (ECM) components is critical for cancer cells to invade the ECM and eventually become metastatic, raising the question whether PRG4 has an anti-invasive effect on cancer cells. Here, we report that a full-length recombinant human PRG4 (rhPRG4) suppresses the ability of the secreted protein transforming growth factor beta (TGFβ) to induce phenotypic disruption of three-dimensional human breast cancer cell-derived organoids by reducing ligand-induced cell invasion. In mechanistic studies, we find that rhPRG4 suppresses TGFβ-induced invasiveness of cancer cells by inhibiting the downstream hyaluronan (HA)-cell surface cluster of differentiation 44 (CD44) signalling axis. Furthermore, we find that rhPRG4 represses TGFβ-dependent increase in the protein abundance of CD44 and of the enzyme HAS2, which is involved in HA biosynthesis. It is widely accepted that TGFβ has both tumor suppressing and tumor promoting roles in cancer. The novel finding that rhPRG4 opposes HAS2 and CD44 induction by TGFβ has implications for downregulating the tumor promoting roles, while maintaining the tumor suppressive aspects of TGFβ actions. Finally, these findings point to rhPRG4's potential clinical utility as a therapeutic treatment for invasive and metastatic breast cancer.

Protein inhibitor of activated STAT genes are differentially expressed in breast tumor tissues

Aim: Protein inhibitor of activated STAT ( PIAS) family includes transcriptional regulator proteins with SUMO E3 ligase activity. They regulate expression of several genes involved in cell proliferation, differentiation and survival. Method: We evaluated expression of PIAS1–4 genes in 54 breast cancer tissues and their paired adjacent noncancerous tissues. Results: PIAS2 and PIAS3 genes were significantly downregulated in tumoral tissues compared with adjacent noncancerous tissues. PIAS1–3 expressions were significantly lower in estrogen receptor (ER+) samples compared with ER- samples while PIAS4 had the opposite trend. PIAS3 expression was significantly higher in grade 1 samples compared with grade 2 samples. Conclusion: These findings highlight the role of PIAS genes in the pathogenesis of breast cancer and their association with determinants of response to antihormone therapies.

The investigation of relevancy between PIAS1 and PIAS2 gene expression and disease severity of multiple sclerosis

Introduction: PIAS1 and PIAS2 (protein inhibitor of activated STAT 1,2) play key roles in the pathogenesis of autoimmune and inflammatory diseases. This study aims to evaluate the gene expression of these factors in multiple sclerosis (MS) patients compared to healthy individuals and correlate them with the severity of MS. Materials and methods: Sixty participants, including 30 patients with MS and 30 healthy controls were studied. The expression of PIAS1 and PIAS2 genes in peripheral blood samples of all participants was measured by real-time PCR. The severity of MS was evaluated using the Expanded Disability Status Scale (EDSS). Finally, we evaluated the correlation between the expression of PIAS1 and PIAS2 genes with disease severity. Results: The expression of PIAS1 gene was increased in patients with MS compared to healthy subjects (P value<.001). Also, there was a significant correlation between the expression of PIAS1 and PIAS2 genes with disease severity according to EDSS. Conclusion: Our study suggests the expression of PIAS1 and PIAS2 genes as a prognostic and diagnostic marker in MS disease.

The SUMO System and TGFβ Signaling Interplay in Regulation of Epithelial-Mesenchymal Transition: Implications for Cancer Progression

Protein post-translational modification by the small ubiquitin-like modifier (SUMO), or SUMOylation, can regulate the stability, subcellular localization or interactome of a protein substrate with key consequences for cellular processes including the Epithelial-Mesenchymal Transition (EMT). The secreted protein Transforming Growth Factor beta (TGFβ) is a potent inducer of EMT in development and homeostasis. Importantly, the ability of TGFβ to induce EMT has been implicated in promoting cancer invasion and metastasis, resistance to chemo/radio therapy, and maintenance of cancer stem cells. Interestingly, TGFβ-induced EMT and the SUMO system intersect with important implications for cancer formation and progression, and novel therapeutics identification.

Transcriptional cofactors Ski and SnoN are major regulators of the TGF-β/Smad signaling pathway in health and disease

The transforming growth factor-β (TGF-β) family plays major pleiotropic roles by regulating many physiological processes in development and tissue homeostasis. The TGF-β signaling pathway outcome relies on the control of the spatial and temporal expression of >500 genes, which depend on the functions of the Smad protein along with those of diverse modulators of this signaling pathway, such as transcriptional factors and cofactors. Ski (Sloan-Kettering Institute) and SnoN (Ski novel) are Smad-interacting proteins that negatively regulate the TGF-β signaling pathway by disrupting the formation of R-Smad/Smad4 complexes, as well as by inhibiting Smad association with the p300/CBP coactivators. The Ski and SnoN transcriptional cofactors recruit diverse corepressors and histone deacetylases to repress gene transcription. The TGF-β/Smad pathway and coregulators Ski and SnoN clearly regulate each other through several positive and negative feedback mechanisms. Thus, these cross-regulatory processes finely modify the TGF-β signaling outcome as they control the magnitude and duration of the TGF-β signals. As a result, any alteration in these regulatory mechanisms may lead to disease development. Therefore, the design of targeted therapies to exert tight control of the levels of negative modulators of the TGF-β pathway, such as Ski and SnoN, is critical to restore cell homeostasis under the specific pathological conditions in which these cofactors are deregulated, such as fibrosis and cancer.

Proteins that repress molecular signaling through the transforming growth factor-beta (TGF-β) pathway offer promising targets for treating cancer and fibrosis. Marina Macías-Silva and colleagues from the National Autonomous University of Mexico in Mexico City review the ways in which a pair of proteins, called Ski and SnoN, interact with downstream mediators of TGF-β to inhibit the effects of this master growth factor. Aberrant levels of Ski and SnoN have been linked to diverse range of diseases involving cell proliferation run amok, and therapies that regulate the expression of these proteins could help normalize TGF-β signaling to healthier physiological levels. For decades, drug companies have tried to target the TGF-β pathway, with limited success. Altering the activity of these repressors instead could provide a roundabout way of remedying pathogenic TGF-β activity in fibrosis and oncology.

Breast Organotypic Cancer Models

Breast cancer is the most common cancer type diagnosed in women, it represents a critical public health problem worldwide, with 1,671,149 estimated new cases and nearly 571,000 related deaths. Research on breast cancer has mainly been conducted using two-dimensional (2D) cell cultures and animal models. The usefulness of these models is reflected in the vast knowledge accumulated over the past decades. However, considering that animal models are three-dimensional (3D) in nature, the validity of the studies using 2D cell cultures has recently been questioned. Although animal models are important in cancer research, ethical questions arise about their use and usefulness as there is no clear predictivity of human disease outcome and they are very expensive and take too much time to obtain results. The poor performance or failure of most cancer drugs suggests that preclinical research on cancer has been based on an over-dependence on inadequate animal models. For these reasons, in the last few years development of alternative models has been prioritized to study human breast cancer behavior, while maintaining a 3D microenvironment, and to reduce the number of experiments conducted in animals. One way to achieve this is using organotypic cultures, which are being more frequently explored in cancer research because they mimic tissue architecture in vivo. These characteristics make organotypic cultures a valuable tool in cancer research as an alternative to replace animal models and for predicting risk assessment in humans. This chapter describes the cultures of multicellular spheroids, organoids, 3D bioreactors, and tumor slices, which are the most widely used organotypic models in breast cancer research.