Separation-of-function MCPH-associated mutations in CPAP affect centriole number and length.

Centrioles are microtubule-based cylindrical ultrastructures characterized by their definite size and robustness. The molecular capping protein, CPAP (also known as CENPJ) engages its N-terminal region with the centriole microtubules to regulate their length. Nevertheless, the conserved C-terminal glycine-rich G-box of CPAP, which interacts with the centriole inner cartwheel protein STIL, is frequently mutated in primary microcephaly (MCPH) patients. Here, we show that two different MCPH-associated variants, E1235V and D1196N in the CPAP G-box, affect distinct functions at centrioles. The E1235V mutation reduces CPAP centriole recruitment and causes overly long centrioles. The D1196N mutation increases centriole numbers without affecting centriole localization. Both mutations prevent binding to STIL, which controls centriole duplication. Our work highlights the involvement of an alternative CEP152-dependent route for CPAP centriole localization. Molecular dynamics simulations suggest that E1235V leads to an increase in G-box flexibility, which could have implications on its molecular interactions. Collectively, we demonstrate that a CPAP region outside the microtubule-interacting domains influences centriole number and length, which translates to spindle defects and reduced cell viability. Our work provides new insights into the molecular causes of primary microcephaly.

Clinical genomics expands the link between erroneous cell division, primary microcephaly and intellectual disability.

Primary microcephaly is a rare neurogenic and genetically heterogeneous disorder characterized by significant brain size reduction that results in numerous neurodevelopmental disorders (NDD) problems, including mild to severe intellectual disability (ID), global developmental delay (GDD), seizures and other congenital malformations. This disorder can arise from a mutation in genes involved in various biological pathways, including those within the brain. We characterized a recessive neurological disorder observed in nine young adults from five independent consanguineous Pakistani families. The disorder is characterized by microcephaly, ID, developmental delay (DD), early-onset epilepsy, recurrent infection, hearing loss, growth retardation, skeletal and limb defects. Through exome sequencing, we identified novel homozygous variants in five genes that were previously associated with brain diseases, namely CENPJ (NM_018451.5: c.1856A > G; p.Lys619Arg), STIL (NM_001048166.1: c.1235C > A; p.(Pro412Gln), CDK5RAP2 (NM_018249.6 c.3935 T > G; p.Leu1312Trp), RBBP8 (NM_203291.2 c.1843C > T; p.Gln615*) and CEP135 (NM_025009.5 c.1469A > G; p.Glu490Gly). These variants were validated by Sanger sequencing across all family members, and in silico structural analysis. Protein 3D homology modeling of wild-type and mutated proteins revealed substantial changes in the structure, suggesting a potential impact on function. Importantly, all identified genes play crucial roles in maintaining genomic integrity during cell division, with CENPJ, STIL, CDK5RAP2, and CEP135 being involved in centrosomal function. Collectively, our findings underscore the link between erroneous cell division, particularly centrosomal function, primary microcephaly and ID.

Spatial analyses of immune cell infiltration in cancer: current methods and future directions: A report of the International Immuno-Oncology Biomarker Working Group on Breast Cancer.

Modern histologic imaging platforms coupled with machine learning methods have provided new opportunities to map the spatial distribution of immune cells in the tumor microenvironment. However, there exists no standardized method for describing or analyzing spatial immune cell data, and most reported spatial analyses are rudimentary. In this review, we provide an overview of two approaches for reporting and analyzing spatial data (raster versus vector-based). We then provide a compendium of spatial immune cell metrics that have been reported in the literature, summarizing prognostic associations in the context of a variety of cancers. We conclude by discussing two well-described clinical biomarkers, the breast cancer stromal tumor infiltrating lymphocytes score and the colon cancer Immunoscore, and describe investigative opportunities to improve clinical utility of these spatial biomarkers. © 2023 The Pathological Society of Great Britain and Ireland.

Cartwheel disassembly regulated by CDK1-cyclin B kinase allows human centriole disengagement and licensing.

Cartwheel assembly is considered the first step in the initiation of procentriole biogenesis; however, the reason for persistence of the assembled human cartwheel structure from S phase to late mitosis remains unclear. Here, we demonstrate mainly using cell synchronization, RNA interference, immunofluorescence and time-lapse-microscopy, biochemical analysis, and methods that the cartwheel persistently assembles and maintains centriole engagement and centrosome integrity during S phase to late G2 phase. Blockade of the continuous accumulation of centriolar Sas-6, a major cartwheel protein, after procentriole formation induces premature centriole disengagement and disrupts pericentriolar matrix integrity. Additionally, we determined that during mitosis, CDK1-cyclin B phosphorylates Sas-6 at T495 and S510, disrupting its binding to cartwheel component STIL and pericentriolar component Nedd1 and promoting cartwheel disassembly and centriole disengagement. Perturbation of this phosphorylation maintains the accumulation of centriolar Sas-6 and retains centriole engagement during mitotic exit, which results in the inhibition of centriole reduplication. Collectively, these data demonstrate that persistent cartwheel assembly after procentriole formation maintains centriole engagement and that this configuration is relieved through phosphorylation of Sas-6 by CDK1-cyclin B during mitosis in human cells.

STIL/AURKA axis promotes cell proliferation by influencing primary cilia formation in bladder cancer.

BACKGROUND: The primary cilia (PC) is a microtubule-based and nonmotile organelle which protrudes from the surface of almost all mammalian cells. At present, PC has been found to be a deficiency or loss in multiple cancers. Restoring PC could be a novel targeting therapy strategy. Our research showed that PC was reduced in human bladder cancer (BLCA) cells, and PC deficiency promotes cell proliferation. However, the concrete mechanisms remain unknown. SCL/TAL1 interrupting locus (STIL), a PC-related protein, was screened in our previous study and could influence the cell cycle by regulating PC in tumor cells. In this study, we aimed to elucidate the function of STIL for PC to explore the underlying mechanism of PC in BLCA. METHODS: Public database analysis, western blot, and enzyme-linked immunosorbent assay (ELISA) were used to screen genes and explore gene expression alteration. Immunofluorescence and western blot were utilized to investigate PC. Wound healing assay, clone formation assay, and CCK-8 assay were used to explore cell migration, growth, and proliferation. The co-immunoprecipitation and western blot were employed to reveal the interaction of STIL and AURKA. RESULTS: We found that high STIL expression is correlated with poor outcomes of BLCA patients. Further analysis revealed that STIL overexpression could inhibit PC formation, activate SHH signaling pathways, and promote cell proliferation. In contrast, STIL-knockdown could promote PC formation, inactivate SHH signaling, and inhibit cell proliferation. Furthermore, we found that the regulatory functions of STIL for PC depend on AURKA. STIL could influence proteasome activity and maintain AURKA stabilization. AURKA-knockdown could reverse PC deficiency caused by STIL overexpression for PC in BLCA cells. We observed that co-knockdown in STIL and AURKA significantly enhanced PC assembly. CONCLUSION: In summary, our result provides a potential therapy target for BLCA based on the restoration of PC.

ncRNAs-mediated overexpression of STIL predict unfavorable prognosis and correlated with the efficacy of immunotherapy of hepatocellular carcinoma.

BACKGROUND: STIL centriolar assembly protein (STIL) is a cytoplasmic protein implicated in cellular growth and proliferation as well as chromosomal stability, which abnormal condition affected tumor immunity and tumor progression. However, the role of STIL in the biological mechanism of hepatocellular carcinoma (HCC) remains unclear. METHODS: Comprehensive bioinformatic approaches, in vitro functional assays, and validation were conducted to elucidate the oncogenic value of STIL in HCC. RESULTS: In the present study, we found that STIL may serve as an independent prognostic indicator and a potential oncogene in HCC. Gene set enrichment analysis (GSEA), and Gene set variation analysis (GSVA) showed that upregulated expression of STIL was positively associated with pathways enriched in the cell cycle and DNA damage response. Subsequently, we identified several non-coding RNAs (ncRNAs) accounting for the upregulation of STIL expression using a combination of in silico bioinformatics approaches (including expression analysis, correlation analysis, and survival analysis). Finally, CCNT2-AS1/SNHG1-has-miR-204-5p-STIL axis was screened out as the most potential upstream ncRNA-related pathway of STIL in HCC. Moreover, STIL expression is highly associated with the infiltration of immune cells, the expression of immune checkpoints, as well as the survival benefit of immunotherapy/chemotherapy. CONCLUSIONS: Our study discloses that ncRNAs-mediated overexpression of STIL independently predicted poor prognosis and correlated with the efficacy of PD-1-targeted immunotherapy in HCC.

Molecular Mechanism of STIL Coiled-Coil Domain Oligomerization.

Coiled-coil domains (CCDs) play key roles in regulating both healthy cellular processes and the pathogenesis of various diseases by controlling protein self-association and protein-protein interactions. Here, we probe the mechanism of oligomerization of a peptide representing the CCD of the STIL protein, a tetrameric multi-domain protein that is over-expressed in several cancers and associated with metastatic spread. STIL tetramerization is mediated both by an intrinsically disordered domain (STIL400-700) and a structured CCD (STIL CCD718-749). Disrupting STIL oligomerization via the CCD inhibits its activity in vivo. We describe a comprehensive biophysical and structural characterization of the concentration-dependent oligomerization of STIL CCD peptide. We combine analytical ultracentrifugation, fluorescence and circular dichroism spectroscopy to probe the STIL CCD peptide assembly in solution and determine dissociation constants of both the dimerization, (KD = 8 ± 2 µM) and tetramerization (KD = 68 ± 2 µM) of the WT STIL CCD peptide. The higher-order oligomers result in increased thermal stability and cooperativity of association. We suggest that this complex oligomerization mechanism regulates the activated levels of STIL in the cell and during centriole duplication. In addition, we present X-ray crystal structures for the CCD containing destabilising (L736E) and stabilising (Q729L) mutations, which reveal dimeric and tetrameric antiparallel coiled-coil structures, respectively. Overall, this study offers a basis for understanding the structural molecular biology of the STIL protein, and how it might be targeted to discover anti-cancer reagents.

Direct interaction between CEP85 and STIL mediates PLK4-driven directed cell migration.

PLK4 has emerged as a prime target for cancer therapeutics, and its overexpression is frequently observed in various types of human cancer. Recent studies have further revealed an unexpected oncogenic activity of PLK4 in regulating cancer cell migration and invasion. However, the molecular basis behind the role of PLK4 in these processes still remains only partly understood. Our previous work has demonstrated that an intact CEP85-STIL binding interface is necessary for robust PLK4 activation and centriole duplication. Here, we show that CEP85 and STIL are also required for directional cancer cell migration. Mutational and functional analyses reveal that the interactions between CEP85, STIL and PLK4 are essential for effective directional cell motility. Mechanistically, we show that PLK4 can drive the recruitment of CEP85 and STIL to the leading edge of cells to promote protrusive activity, and that downregulation of CEP85 and STIL leads to a reduction in ARP2 (also known as ACTR2) phosphorylation and reorganization of the actin cytoskeleton, which in turn impairs cell migration. Collectively, our studies provide molecular insight into the important role of the CEP85-STIL complex in modulating PLK4-driven cancer cell migration.This article has an associated First Person interview with the first author of the paper.

Drosophila Sas-6, Ana2 and Sas-4 self-organise into macromolecular structures that can be used to probe centriole and centrosome assembly.

Centriole assembly requires a small number of conserved proteins. The precise pathway of centriole assembly has been difficult to study, as the lack of any one of the core assembly proteins [Plk4, Ana2 (the homologue of mammalian STIL), Sas-6, Sas-4 (mammalian CPAP) or Asl (mammalian Cep152)] leads to the absence of centrioles. Here, we use Sas-6 and Ana2 particles (SAPs) as a new model to probe the pathway of centriole and centrosome assembly. SAPs form in Drosophila eggs or embryos when Sas-6 and Ana2 are overexpressed. SAP assembly requires Sas-4, but not Plk4, whereas Asl helps to initiate SAP assembly but is not required for SAP growth. Although not centrioles, SAPs recruit and organise many centriole and centrosome components, nucleate microtubules, organise actin structures and compete with endogenous centrosomes to form mitotic spindle poles. SAPs require Asl to efficiently recruit pericentriolar material (PCM), but Spd-2 (the homologue of mammalian Cep192) can promote some PCM assembly independently of Asl. These observations provide new insights into the pathways of centriole and centrosome assembly.

A novel HIF1α-STIL-FOXM1 axis regulates tumor metastasis.

BACKGROUND: Metastasis is the major cause of morbidity and mortality in cancer that involves in multiple steps including epithelial-mesenchymal transition (EMT) process. Centrosome is an organelle that functions as the major microtubule organizing center (MTOC), and centrosome abnormalities are commonly correlated with tumor aggressiveness. However, the conclusive mechanisms indicating specific centrosomal proteins participated in tumor progression and metastasis remain largely unknown. METHODS: The expression levels of centriolar/centrosomal genes in various types of cancers were first examined by in silico analysis of the data derived from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and European Bioinformatics Institute (EBI) datasets. The expression of STIL (SCL/TAL1-interrupting locus) protein in clinical specimens was further assessed by Immunohistochemistry (IHC) analysis and the oncogenic roles of STIL in tumorigenesis were analyzed using in vitro and in vivo assays, including cell migration, invasion, xenograft tumor formation, and metastasis assays. The transcriptome differences between low- and high-STIL expression cells were analyzed by RNA-seq to uncover candidate genes involved in oncogenic pathways. The quantitative polymerase chain reaction (qPCR) and reporter assays were performed to confirm the results. The chromatin immunoprecipitation (ChIP)-qPCR assay was applied to demonstrate the binding of transcriptional factors to the promoter. RESULTS: The expression of STIL shows the most significant increase in lung and various other types of cancers, and is highly associated with patients' survival rate. Depletion of STIL inhibits tumor growth and metastasis. Interestingly, excess STIL activates the EMT pathway, and subsequently enhances cancer cell migration and invasion. Importantly, we reveal an unexpected role of STIL in tumor metastasis. A subset of STIL translocate into nucleus and associate with FOXM1 (Forkhead box protein M1) to promote tumor metastasis and stemness via FOXM1-mediated downstream target genes. Furthermore, we demonstrate that hypoxia-inducible factor 1α (HIF1α) directly binds to the STIL promoter and upregulates STIL expression under hypoxic condition. CONCLUSIONS: Our findings indicate that STIL promotes tumor metastasis through the HIF1α-STIL-FOXM1 axis, and highlight the importance of STIL as a promising therapeutic target for lung cancer treatment.

The effect of neoadjuvant chemotherapy on tumor-infiltrating lymphocytes in patients with breast cancer.

Aim: This study investigated the effect of neoadjuvant chemotherapy (NAC) on stromal tumor-infiltrating lymphocytes (sTILs) and their treatment response. Materials & methods: 115 patients with pre-NAC core biopsies and post-NAC surgical resection specimens were reviewed. Results: There was no significant change between pre- and post-treatment sTILs. Both pre- and post-NAC sTILs were significantly lower in patients with luminal A subtype. An increase in sTILs was observed in 21 (25.9%) patients after NAC, a decrease in 29 (35.8%) and no change in 31 (38.3%; p = 0.07). Pretreatment sTIL density was independent predictor of pathological complete response in multivariate analyses (odds ratio: 1.025, 95% CI: 1.003-1.047; p = 0.023). Conclusion: High sTIL density in core biopsies was independently related to pathological complete response. In addition, ER appears to be the most crucial factor determining the rate of sTIL.

New studies have shown that the tumor microenvironment is critical in tumor behavior. Immune cells surrounding tumor cells are the main components of the tumor microenvironment. Our study aimed to investigate the change in immune cells before and after chemotherapy in breast cancer patients. Our study included 115 patients. All patients underwent chemotherapy before surgery to shrink the tumor. Tru-cut biopsy pieces and the breast tissue obtained after surgery were examined. The presence of estrogen or progesterone receptors on tumor cells decreased the number of immune cells surrounding the tumor cells. The number of immune cells did not decrease after chemotherapy. Another finding was that the greater the number of immune cells around the tumor, the more likely that the tumor would disappear after chemotherapy.

Circular RNA Circ-STIL Contributes to Cell Growth and Metastasis in Hepatocellular Carcinoma via Regulating miR-345-5p/AQP3 Axis.

BACKGROUND: Circular RNAs (circRNAs) are implicated in the pathogenesis and development of hepatocellular carcinoma (HCC). However, the function and latent mechanism of circ-STIL in HCC have not been elucidated. AIMS: This study was designed to explore the precise role and underlying molecular mechanism of circ-STIL in HCC advancement. METHODS: The expression levels of circ-STIL, SCL/TAL1 interrupting locus (STIL), miR-345-5p and aquaporin-3 (AQP3) were measured by quantitative real-time polymerase chain reaction or western blot. Cell proliferation was assessed by 3-(4,5-dimethylthizol-2-yl)-2,5-diphenyltetrazolium bromide assay and colony formation assay. Cell apoptosis was analyzed by flow cytometry. Transwell assay was conducted to analyze cell migratory and invasive capacities. The interactions among circ-STIL, miR-345-5p and AQP3 were confirmed by dual-luciferase reporter and RNA immunoprecipitation assays. Xenograft tumor model was established to analyze the role of circ-STIL in HCC in vivo. RESULTS: Circ-STIL was upregulated in HCC tissues and cells. Circ-STIL knockdown inhibited HCC cell progression by reducing cell proliferation, migration and invasion and promoting cell apoptosis. MiR-345-5p was a direct target of circ-STIL, and AQP3 was targeted by miR-345-5p in HCC. Circ-STIL knockdown or miR-345-5p overexpression impeded cell malignant behaviors in HCC cells, and the effects could be reversed by miR-345-5p silence or AQP3 enhancement, respectively. Meanwhile, circ-STIL regulated AQP3 expression by sponging miR-345-5p. Besides, circ-STIL downregulation retarded HCC tumor growth in vivo. CONCLUSION: Circ-STIL knockdown suppressed HCC development by regulating miR-345-5p/AQP3 pathway, which might provide a promising target for HCC therapy.

Multiplex immunofluorescence to measure dynamic changes in tumor-infiltrating lymphocytes and PD-L1 in early-stage breast cancer.

BACKGROUND: The H&E stromal tumor-infiltrating lymphocyte (sTIL) score and programmed death ligand 1 (PD-L1) SP142 immunohistochemistry assay are prognostic and predictive in early-stage breast cancer, but are operator-dependent and may have insufficient precision to characterize dynamic changes in sTILs/PD-L1 in the context of clinical research. We illustrate how multiplex immunofluorescence (mIF) combined with statistical modeling can be used to precisely estimate dynamic changes in sTIL score, PD-L1 expression, and other immune variables from a single paraffin-embedded slide, thus enabling comprehensive characterization of activity of novel immunotherapy agents. METHODS: Serial tissue was obtained from a recent clinical trial evaluating loco-regional cytokine delivery as a strategy to promote immune cell infiltration and activation in breast tumors. Pre-treatment biopsies and post-treatment tumor resections were analyzed by mIF (PerkinElmer Vectra) using an antibody panel that characterized tumor cells (cytokeratin-positive), immune cells (CD3, CD8, CD163, FoxP3), and PD-L1 expression. mIF estimates of sTIL score and PD-L1 expression were compared to the H&E/SP142 clinical assays. Hierarchical linear modeling was utilized to compare pre- and post-treatment immune cell expression, account for correlation of time-dependent measurement, variation across high-powered magnification views within each subject, and variation between subjects. Simulation methods (Monte Carlo, bootstrapping) were used to evaluate the impact of model and tissue sample size on statistical power. RESULTS: mIF estimates of sTIL and PD-L1 expression were strongly correlated with their respective clinical assays (p < .001). Hierarchical linear modeling resulted in more precise estimates of treatment-related increases in sTIL, PD-L1, and other metrics such as CD8+ tumor nest infiltration. Statistical precision was dependent on adequate tissue sampling, with at least 15 high-powered fields recommended per specimen. Compared to conventional t-testing of means, hierarchical linear modeling was associated with substantial reductions in enrollment size required (n = 25➔n = 13) to detect the observed increases in sTIL/PD-L1. CONCLUSION: mIF is useful for quantifying treatment-related dynamic changes in sTILs/PD-L1 and is concordant with clinical assays, but with greater precision. Hierarchical linear modeling can mitigate the effects of intratumoral heterogeneity on immune cell count estimations, allowing for more efficient detection of treatment-related pharmocodynamic effects in the context of clinical trials. TRIAL REGISTRATION: NCT02950259 .

Centriole assembly at a glance.

The centriole organelle consists of microtubules (MTs) that exhibit a striking 9-fold radial symmetry. Centrioles play fundamental roles across eukaryotes, notably in cell signaling, motility and division. In this Cell Science at a Glance article and accompanying poster, we cover the cellular life cycle of this organelle - from assembly to disappearance - focusing on human centrioles. The journey begins at the end of mitosis when centriole pairs disengage and the newly formed centrioles mature to begin a new duplication cycle. Selection of a single site of procentriole emergence through focusing of polo-like kinase 4 (PLK4) and the resulting assembly of spindle assembly abnormal protein 6 (SAS-6) into a cartwheel element are evoked next. Subsequently, we cover the recruitment of peripheral components that include the pinhead structure, MTs and the MT-connecting A-C linker. The function of centrioles in recruiting pericentriolar material (PCM) and in forming the template of the axoneme are then introduced, followed by a mention of circumstances in which centrioles form de novo or are eliminated.

The biological function and clinical significance of STIL in osteosarcoma.

BACKGROUND: SCL/TAL1 interrupting locus (STIL) is associated with the progression of several tumors; however, the biological role of STIL in osteosarcoma remains poorly understood. METHODS: In this study, the clinical significance of STIL in osteosarcoma was analyzed by gene chip data recorded in public databases. STIL expression was silenced in osteosarcoma cell lines to observe the effects on proliferation, apoptosis, invasion, and migration. Differentially expressed genes (DEGs) in the osteosarcoma chip were analyzed using The Limma package, and STIL co-expressed genes were obtained via the Pearson correlation coefficient. The potential molecular mechanism of STIL in osteosarcoma was further explored by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. RESULTS: Osteosarcoma was associated with higher STIL expression compared to the control samples, and the standardized mean difference (SMD) was 1.52. STIL also had a good ability to distinguish osteosarcoma from non-osteosarcoma samples [area under the curve (AUC) = 0.96]. After silencing STIL, osteosarcoma cell proliferation decreased, apoptosis increased, and the migratory and invasion ability decreased. A total of 294 STIL differentially co-expressed genes were screened, and a bioinformatics analysis found that differentially co-expressed genes were primarily enriched in the cell signaling pathways. The protein-protein interaction (PPI) network indicated that the hub differentially co-expressed genes of STIL were CDK1, CCNB2, CDC20, CCNA2, BUB1, and AURKB. CONCLUSIONS: STIL is associated with osteosarcoma proliferation and invasion, and may be promote the progression of osteosarcoma by regulating the expression of CDK1, CCNB2, CDC20, CCNA2, BUB1 and AURKB.

Genomic landscape and evolutionary trajectories of ovarian cancer precursor lesions.

The clonal relationship between ovarian high-grade serous carcinoma (HGSC) and its presumed precursor lesion, serous tubal intraepithelial carcinoma (STIC), has been reported. However, when analyzing patients with concurrent ovarian carcinoma and tubal lesion, the extensive carcinoma tissues present at diagnosis may have effaced the natural habitat of precursor clone(s), obscuring tumor clonal evolutionary history, or may have disseminated to anatomically adjacent fimbriae ends, masquerading as precursor lesions. To circumvent these limitations, we analyzed the genomic landscape of incidental tubal precursor lesions including p53 signature, dormant STIC or serous tubal intraepithelial lesion (STIL) and proliferative STIC in women without ovarian carcinoma or any cancer diagnosis using whole-exome sequencing and amplicon sequencing. In three of the four cancer-free women with multiple discrete tubal lesions we observed non-identical TP53 mutations between precursor lesions from the same individual. In one of the four women with co-existing ovarian HGSC and tubal precursor lesion we found non-identical TP53 mutations and a lack of common mutations shared between her precursor lesion and carcinoma. Analyzing the evolutionary history of multiple tubal lesions in the same four patients with concurrent ovarian carcinoma indicated distinct evolution trajectories. Collectively, the results support diverse clonal origins of tubal precursor lesions at the very early stages of tumorigenesis. Mathematical modeling based on lesion-specific proliferation rates indicated that p53 signature and dormant STIC may take a prolonged time (two decades or more) to develop into STIC, whereas STIC may progress to carcinoma in a much shorter time (6 years). The above findings may have implications for future research aimed at prevention and early detection of ovarian cancer. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Knockdown of STIL suppresses the progression of gastric cancer by down-regulating the IGF-1/PI3K/AKT pathway.

SCL/TAL1 interrupting locus (STIL) regulates the mitotic centrosome to promote the centriolar replication and cell cycling, and is associated with malignancies. However, the role and mechanism of STIL in gastric cancer (GC) remain elusive. STIL expression in GC tissue microarray was detected by immunohistochemistry (IHC). GC cells were transduced with control lentivirus or lentivirus for expression STIL-specific shRNA and the effect of STIL silencing on the malignant behaviors of GC cells was measured in vitro and in vivo. The potential mechanisms underlying the action of STIL were analyzed by transcriptome microarray and bioinformatics. STIL expression was up-regulated in GC tissues both in our cohort and the data from the cancer genome atlas, and positively associated with T stage and poor overall survival of GC patients. Knockdown of STIL significantly inhibited the proliferation and clonogenicity of human GC cells and attenuated the growth of implanted GC in vivo. Furthermore, STIL silencing induced cell cycle arrest in G2/M phase and apoptosis of GC cells. Transcriptome analysis indicated that STIL silencing modulated many gene expression, particularly for down-regulating the IGF-1/PI3K/AKT pathway. In addition, treatment with SC79, an AKT activator, significantly mitigated the effect of STIL-silencing in GC cells. In conclusion, STIL promotes gastric carcinogenesis and progression by enhancing the IGF-1/PI3K/AKT signaling, and STIL may be a novel target for intervention of GC.

Infiltrating stromal immune cells in inflammatory breast cancer are associated with an improved outcome and increased PD-L1 expression.

BACKGROUND: Inflammatory breast cancer (IBC) is a rare and rapidly progressive form of invasive breast cancer. The aim of this study was to explore the clinical evolution, stromal tumour-infiltrating lymphocytes (sTIL) infiltration and programmed death-ligand 1 (PD-L1) expression in a large IBC cohort. PATIENTS AND METHODS: Data were collected prospectively from patients with IBC as part of an international collaborative effort since 1996. In total, 143 patients with IBC starting treatment between June 1996 and December 2016 were included. Clinicopathological variables were collected, and sTIL were scored by two pathologists on standard H&E stained sections. PD-L1 expression was assessed using a validated PD-L1 (SP142) assay. A validation cohort of 64 patients with IBC was used to test our findings. RESULTS: Survival outcomes of IBC remained poor with a 5-year overall survival (OS) of 45.6%. OS was significantly better in patients with primary non-metastatic disease who received taxane-containing (neo)adjuvant therapy (P = 0.01), had a hormone receptor-positive tumour (P = 0.001) and had lower cN stage at diagnosis (P = 0.001). PD-L1 positivity on immune cells (42.9%) was higher in IBC than in non-IBC in both our patient samples and the validation cohort. Furthermore, PD-L1 expression predicted pCR (P = 0.002) and correlated with sTIL infiltration (P < 0.001). sTIL infiltration of more than 10% of the stroma was a significant predictor of improved OS (HR 0.47, 95% CI 0.27-0.81, P = 0.006) in a multivariate model. CONCLUSIONS: IBC is characterised by poor survival and high PD-L1 immunoreactivity on sTIL. This suggests a role for PD1/PD-L1 inhibitors in the treatment of IBC. Furthermore, we showed that PD-L1 expression predicts response to neo-adjuvant therapy and that sTIL have prognostic significance in IBC.

[Effect of STIL on the Gene Expression Profile of Gastric Cancer Cells].

Objective To explore the molecular mechanism underlying gastric carcinogenesis and progression by using gene expression profiling array together with bioinformatics. Methods Lentivirus short hairpin RNA targeting STIL(ShSTIL)and scrambled sequence RNA(ShCon)were transduced into the gastric cancer cell line SGC-7901.RNA extraction,complementary DNA synthesis,construction of biotin-labelled amplified RNA probes,and hybridization with gene expression profile were consecutively performed.We collected corresponding data and analyzed differentially expressing genes(DEGs),followed by the analysis of gene ontology(GO)and Kyoto encyclopedia of genes and genomes(KEGG)enrichment,transcription factor regulating network,and protein-protein interacting networks. Results Compared with ShCon,a total of 417 and 87 genes were respectively down-regulated and up-regulated,respectively,in the ShSTIL group(P<0.05,fold change>1 or <-1).GO and KEGG enrichment analysis indicated that genes regulated by STIL were localized in cytoplasm,extracellular exosome,Golgi apparatus and various biomembranes,and were implicated in the ubiquitin-mediated proteolysis,P53 signaling pathway,and pathways regulating pluripotency of stem cells.Evaluation on genes enriched in KEGG pathways,regulation of transcription factors,and protein-protein interacting network demonstrated that IGF1R,STUB1,SKP2,and FOXO1 were localized at the centre of the network and played a key role in the development and progression of gastric cancer. Conclusion Through the protein-protein interactions,STIL may activate E3 ubiquitin ligase STUB1 or SKP2,promote the proteolysis of FOXO1-a transcription factor,regulate the expression of IGF1R,and thus promote gastric carcinogenesis and progression.

Origins of STIL-TAL1 fusion genes in children who later developed paediatric T-cell acute lymphoblastic leukaemia: An investigation of neonatal blood spots.

SCL/TAL1 interrupting locus (STIL)-T-cell acute leukaemia (TAL1) fusion genes are present in approximately 11-27% of children with paediatric T-cell acute lymphoblastic leukaemia (T-ALL), but the developmental timing of the rearrangement is still unknown. To investigate whether the fusion gene can be detected in neonatal blood spots (NBSs) from paediatric patients diagnosed with T-cell ALL, we analysed DNA from 38 paediatric patients with T-ALL by nested polymerase chain reaction and electrophoresis. The STIL-TAL1 fusion gene was not detected in NBSs from any of the 38 patients with T-ALL, suggesting that STIL-TAL1 fusion genes are most probably postnatal events in paediatric T-ALL.