Inactivation of pentraxin 3 suppresses M2-like macrophage activity and immunosuppression in colon cancer.

BACKGROUND: The tumor microenvironment is characterized by inflammation-like and immunosuppression situations. Although cancer-associated fibroblasts (CAFs) are among the major stromal cell types in various solid cancers, including colon cancer, the interactions between CAFs and immune cells remains largely uncharacterized. Pentraxin 3 (PTX3) is responsive to proinflammatory cytokines and modulates immunity and tissue remodeling, but its involvement in tumor progression appears to be context-dependent and is unclear. METHODS: Open-access databases were utilized to examine the association of PTX3 expression and the fibroblast signature in colon cancer. Loss-of-function assays, including studies in tamoxifen-induced Ptx3 knockout mice and treatment with an anti-PTX3 neutralizing antibody (WHC-001), were conducted to assess the involvement of PTX3 in colon cancer progression as well as its immunosuppressive effect. Finally, bioinformatic analyses and in vitro assays were performed to reveal the downstream effectors and decipher the involvement of the CREB1/CEBPB axis in response to PTX3 and PTX3-induced promotion of M2 macrophage polarization. RESULTS: Clinically, higher PTX3 expression was positively correlated with fibroblasts and inflammatory response signatures and associated with a poor survival outcome in colon cancer patients. Blockade of PTX3 significantly reduced stromal cell-mediated tumor development. The decrease of the M2 macrophage population and an increase of the cytotoxic CD8+ T-cell population were observed following PTX3 inactivation in allografted colon tumors. We further revealed that activation of cyclic AMP-responsive element-binding protein 1 (CREB1) mediated the PTX3-induced promotion of M2 macrophage polarization. CONCLUSIONS: PTX3 contributes to stromal cell-mediated protumor immunity by increasing M2-like macrophage polarization, and inhibition of PTX3 with WHC-001 is a potential therapeutic strategy for colon cancer.

NEIL3 promotes hepatoma epithelial-mesenchymal transition by activating the BRAF/MEK/ERK/TWIST signaling pathway.

Hepatocellular carcinoma (HCC) is among the most prevalent visceral neoplasms. So far, reliable biomarkers for predicting HCC recurrence in patients undergoing surgery are far from adequate. In the aim of searching for genetic biomarkers involved in HCC development, we performed analyses of cDNA microarrays and found that the DNA repair gene NEIL3 was remarkably overexpressed in tumors. NEIL3 belongs to the Fpg/Nei protein superfamily, which contains DNA glycosylase activity required for the base excision repair for DNA lesions. Notably, the other Fpg/Nei family proteins NEIL1 and NEIL2, which have the same glycosylase activity as NEIL3, were not elevated in HCC; NEIL3 was specifically induced to participate in HCC development independently of its glycosylase activity. Using RNA-seq and invasion/migration assays, we found that NEIL3 elevated the expression of epithelial-mesenchymal transition (EMT) factors, including the E/N-cadherin switch and the transcription of MMP genes, and promoted the invasion, migration, and stemness phenotypes of HCC cells. Moreover, NEIL3 directly interacted with the key EMT player TWIST1 to enhance invasion and migration activities. In mouse orthotopic HCC studies, NEIL3 overexpression also caused a prominent E-cadherin decrease, tumor volume increase, and lung metastasis, indicating that NEIL3 led to EMT and tumor metastasis in mice. We further found that NEIL3 induced the transcription of MDR1 (ABCB1) and BRAF genes through the canonical E-box (CANNTG) promoter region, which the TWIST1 transcription factor recognizes and binds to, leading to the BRAF/MEK/ERK pathway-mediated cell proliferation as well as anti-cancer drug resistance, respectively. In the HCC cohort, the tumor NEIL3 level demonstrated a high positive correlation with disease-free and overall survival after surgery. In conclusion, NEIL3 activated the BRAF/MEK/ERK/TWIST pathway-mediated EMT and therapeutic resistances, leading to HCC progression. Targeted inhibition of NEIL3 in HCC individuals with NEIL3 induction is a promising therapeutic approach. © 2022 The Pathological Society of Great Britain and Ireland.

Epstein-Barr virus latent membrane protein-1 upregulates autophagy and promotes viability in Hodgkin lymphoma: Implications for targeted therapy.

Hodgkin lymphoma (HL) is composed of neoplastic Hodgkin and Reed-Sternberg cells in an inflammatory background. The neoplastic cells are derived from germinal center B cells that, in most cases, are infected by Epstein-Barr virus (EBV), which may play a role in tumorigenesis. Given that EBV-latent membrane protein 1 (LMP1) regulates autophagy in B cells, we explored the role of autophagy mediated by EBV or LMP1 in HL. We found that EBV-LMP1 transfection in HL cells induced a modest increase in autophagy signals, attenuated starvation-induced autophagic stress, and alleviated autophagy inhibition- or doxorubicin-induced cell death. LMP1 knockdown leads to decreased autophagy LC3 signals. A xenograft mouse model further showed that EBV infection significantly increased expression of the autophagy marker LC3 in HL cells. Clinically, LC3 was expressed in 15% (19/127) of HL samples, but was absent in all cases of nodular lymphocyte-predominant and lymphocyte-rich classic HL cases. Although expression of LC3 was not correlated with EBV status or clinical outcome, autophagic blockade effectively eradicated LMP1-positive HL xenografts with better efficacy than LMP1-negative HL xenografts. Collectively, these results suggest that EBV-LMP1 enhances autophagy and promotes the viability of HL cells. Autophagic inhibition may be a potential therapeutic strategy for treating patients with HL, especially EBV-positive cases.

Hepatitis B virus X protein (HBx) enhances centrosomal P4.1-associated protein (CPAP) expression to promote hepatocarcinogenesis.

BACKGROUND: Our previous report suggested that centrosomal P4.1-associated protein (CPAP) is required for Hepatitis B virus (HBV) encoded non-structure protein X (HBx)-mediated nuclear factor kappa light chain enhancer of activated B cells (NF-κB) activation. CPAP is overexpressed in HBV-associated hepatocellular carcinoma (HCC); however, the interaction between CPAP and HBx in HBV-HCC remains unclear. METHODS: The mRNA expression of CPAP and HBx was analyzed by quantitative-PCR (Q-PCR). NF-κB transcriptional activity and CPAP promoter activity were determined using a reporter assay in Huh7 and Hep3B cells. Immunoprecipitation (IP) and in situ proximal ligation assay (PLA) were performed to detect the interaction between CPAP and HBx. Chromatin-IP was used to detect the association of cAMP response element binding protein (CREB) and HBx with the CPAP promoter. Cell proliferation was measured using cell counting kit CCK-8, Bromodeoxyuridine (5-bromo-2'-deoxyuridine, BrdU) incorporation, and clonogenic assays. The tumorigenic effects of CPAP were determined using xenograft animal models. RESULTS: HBx can transcriptionally up-regulate CPAP via interacting with CREB. Overexpressed CPAP directly interacted with HBx to promote HBx-mediated cell proliferation and migration; SUMO modification of CPAP was involved in interacting with HBx. Knocked-down expression of CPAP decreased the HBx-mediated tumorigenic effects, including cytokines secretion. Interestingly, overexpressed CPAP maintained the HBx protein stability in an NF-κB-dependent manner; and the expression levels of CPAP and HBx were positively correlated with the activation status of NF-κB in HCC. Increased expression of CPAP and CREB mRNAs existed in the high-risk group with a lower survival rate in HBV-HCC. CONCLUSION: The interaction between CPAP and HBx can provide a microenvironment to facilitate HCC development via enhancing NF-κB activation, inflammatory cytokine production, and cancer malignancies. This study not only sheds light on the role of CPAP in HBV-associated HCC, but also provides CPAP as a potential target for blocking the hyper-activated NF-κB in HCC.

Role of Dicer in regulating oxaliplatin resistance of colon cancer cells.

Colorectal cancer (CRC) is a major health problem due to its high mortality rate. The incidence of CRC is increasing in young individuals. Oxaliplatin (OXA) is an approved third-generation drug and is used for first-line chemotherapy in CRC. Although current standard chemotherapy improves the overall survival of CRC patients, an increasing number of reports of OXA resistance in CRC therapy indicates that resistance has become an urgent problem in clinical applications. Dicer is a critical enzyme involved in miRNA maturation. The expression of Dicer has been reported to be involved in the resistance to various drugs in cancer. In the present study, we aimed to investigate the role of Dicer in OXA resistance in CRC. We found that OXA treatment inhibited Dicer expression through decreasing the protein stability. OXA-induced Dicer protein degradation occurred through both proteasomal and lysosomal proteolysis, while the CHIP E3 ligase was involved in OXA-mediated Dicer ubiquitination and degradation. We established stable OXA-resistant clones from CRC cells, and observed that the CHIP E3 ligase was decreased, along with the increased Dicer expression in OXA-resistant cells. Knockdown of Dicer resensitized CRC cells to OXA treatment. In this study, we have revealed the role of miRNA biogenesis factors in OXA resistance in CRC cells.

Pin1 acts as a negative regulator of the G2/M transition by interacting with the Aurora-A-Bora complex.

Pin1 was the first prolyl isomerase identified that is involved in cell division. The mechanism by which Pin1 acts as a negative regulator of mitotic activity in G2 phase remains unclear. Here, we found that Aurora A can interact with and phosphorylate Pin1 at Ser16, which suppresses the G2/M function of Pin1 by disrupting its binding ability and mitotic entry. Our results also show that phosphorylation of Bora at Ser274 and Ser278 is crucial for binding of Pin1. Through the interaction, Pin1 can alter the cytoplasmic translocation of Bora and promote premature degradation by ß-TrCP, which results in a delay in mitotic entry. Together with the results that Pin1 protein levels do not significantly fluctuate during cell-cycle progression and Aurora A suppresses Pin1 G2/M function, our data demonstrate that a gain of Pin1 function can override the Aurora-A-mediated functional suppression of Pin1. Collectively, these results highlight the physiological significance of Aurora-A-mediated Pin1 Ser16 phosphorylation for mitotic entry and the suppression of Pin1 is functionally linked to the regulation of mitotic entry through the Aurora-A-Bora complex.

CDKN1A-mediated responsiveness of MLL-AF4-positive acute lymphoblastic leukemia to Aurora kinase-A inhibitors.

Overexpression of Aurora kinases is largely observed in many cancers, including hematologic malignancies. In this study, we investigated the effects and molecular mechanisms of Aurora kinase inhibitors in acute lymphoblastic leukemia (ALL). Western blot analysis showed that both Aurora-A and Aurora-B are overexpressed in ALL cell lines and primary ALL cells. Both VE-465 and VX-680 effectively inhibited Aurora kinase activities in nine ALL cell lines, which exhibited different susceptibilities to the inhibitors. Cells sensitive to Aurora kinase inhibitors underwent apoptosis at an IC50 of ∼10-30 nM and displayed a phenotype of Aurora-A inhibition, whereas cells resistant to Aurora kinase inhibitors (with an IC50 more than 10 µM) accumulated polyploidy, which may have resulted from Aurora-B inhibition. Drug susceptibility of ALL cell lines was not correlated with the expression level or activation status of Aurora kinases. Interestingly, RS4;11 and MV4;11 cells, which contain the MLL-AF4 gene, were both sensitive to Aurora kinase-A inhibitors treatment. Complementary DNA (cDNA) microarray analysis suggested that CDKN1A might govern the drug responsiveness of ALL cell lines in a TP53-independent manner. Most importantly, primary ALL cells with MLL-AF4 and CDKN1A expression were sensitive to Aurora kinase inhibitors. Our study suggests CDKN1A could be a potential biomarker in determining the drug responsiveness of Aurora kinase inhibitors in ALL, particularly in MLL-AF4-positive patients.

Monoclonality and cytogenetic abnormalities in hyaline vascular Castleman disease.

Hyaline vascular Castleman disease is traditionally regarded as a reactive hyperplastic process. Occasional cases, however, have been reported with cytogenetic anomalies bringing this concept into question. In this study, we used conventional and methylation-specific polymerase chain reaction methods to assess the human androgen receptor α (HUMARA) gene in 29 female patients with hyaline vascular Castleman disease and compared the results with three cases of plasma cell Castleman disease and 20 cases of age-matched lymphoid hyperplasia. We also assessed for immunoglobulin gene and T-cell receptor gene rearrangements, and conventional cytogenetic analysis was performed in three cases of hyaline vascular Castleman disease. In cases with informative results, conventional and methylation-specific human androgen receptor α gene analyses yielded a monoclonal pattern in 10 of 19 (53%) and 17 of 23 (74%) cases of hyaline vascular Castleman disease, respectively. A monoclonal pattern was also detected in three cases of plasma cell Castleman disease but not in cases of lymphoid hyperplasia. The frequency of monoclonality was higher for lesions >5 cm in size (100%) and for the stromal-rich variant (91%). Cytogenetic abnormalities in stromal cells were revealed in two cases of hyaline vascular Castleman disease and no cases showed monoclonal immunoglobulin or T-cell receptor gene rearrangements. Follow-up data showed persistent disease in 4 of 23 (17%) patients. We conclude that hyaline vascular Castleman disease is often a monoclonal proliferation, most likely of lymph node stromal cells.

Neutralizing IL-16 enhances the efficacy of targeting Aurora-A therapy in colorectal cancer with high lymphocyte infiltration through restoring anti-tumor immunity.

Cancer cells can evade immune elimination by activating immunosuppressive signaling pathways in the tumor microenvironment (TME). Targeting immunosuppressive signaling pathways to promote antitumor immunity has become an attractive strategy for cancer therapy. Aurora-A is a well-known oncoprotein that plays a critical role in tumor progression, and its inhibition is considered a promising strategy for treating cancers. However, targeting Aurora-A has not yet got a breakthrough in clinical trials. Recent reports have indicated that inhibition of oncoproteins may reduce antitumor immunity, but the role of tumor-intrinsic Aurora-A in regulating antitumor immunity remains unclear. In this study, we demonstrated that in tumors with high lymphocyte infiltration (hot tumors), higher tumor-intrinsic Aurora-A expression is associated with a better prognosis in CRC patients. Mechanically, tumor-intrinsic Aurora-A promotes the cytotoxic activity of CD8+ T cells in immune hot CRC via negatively regulating interleukin-16 (IL-16), and the upregulation of IL-16 may impair the therapeutic effect of Aurora-A inhibition. Consequently, combination treatment with IL-16 neutralization improves the therapeutic response to Aurora-A inhibitors in immune hot CRC tumors. Our study provides evidence that tumor-intrinsic Aurora-A contributes to anti-tumor immunity depending on the status of lymphocyte infiltration, highlighting the importance of considering this aspect in cancer therapy targeting Aurora-A. Importantly, our results suggest that combining Aurora-A inhibitors with IL-16-neutralizing antibodies may represent a novel and effective approach for cancer therapy, particularly in tumors with high levels of lymphocyte infiltration.

Store-operated calcium entry inhibits primary ciliogenesis via the activation of Aurora A.

The primary cilium is an antenna-like organelle protruding from the cell surface that can detect physical and chemical stimuli in the extracellular space to activate specific signaling pathways and downstream gene expressions. Calcium ion (Ca2+ ) signaling regulates a wide spectrum of cellular processes, including fertilization, proliferation, differentiation, muscle contraction, migration, and death. This study investigated the effects of the regulation of cytosolic Ca2+ levels on ciliogenesis using chemical, genetic, and optogenetic approaches. We found that ionomycin-induced Ca2+ influx inhibited ciliogenesis and Ca2+ chelator BATPA-AM-induced Ca2+ depletion promoted ciliogenesis. In addition, store-operated Ca2+ entry and the endoplasmic reticulum Ca2+ sensor stromal interaction molecule 1 (STIM1) negatively regulated ciliogenesis. Moreover, an optogenetic platform was used to create different Ca2+ oscillation patterns by manipulating lighting parameters, including density, frequency, exposure time, and duration. Light-activated Ca2+ -translocating channelrhodopsin (CatCh) is activated by 470-nm blue light to induce Ca2+ influx. Our results show that high-frequency Ca2+ oscillations decrease ciliogenesis. Furthermore, the inhibition of cilia formation induced by Ca2+ may occur via the activation of Aurora kinase A. Cilia not only induce Ca2+ signaling but also regulate cilia formation by Ca2+ signaling.

58-kDa microspherule protein (MSP58) is novel Brahma-related gene 1 (BRG1)-associated protein that modulates p53/p21 senescence pathway.

The nucleolar 58-kDa microspherule protein (MSP58) protein is a candidate oncogene implicated in modulating cellular proliferation and malignant transformation. In this study, we show that knocking down MSP58 expression caused aneuploidy and led to apoptosis, whereas ectopic expression of MSP58 regulated cell proliferation in a context-dependent manner. Specifically, ectopic expression of MSP58 in normal human IMR90 and Hs68 diploid fibroblasts, the H184B5F5/M10 mammary epithelial cell line, HT1080 fibrosarcoma cells, primary mouse embryonic fibroblasts, and immortalized NIH3T3 fibroblasts resulted in induction of premature senescence, an enlarged and flattened cellular morphology, and increased senescence-associated ß-galactosidase activity. MSP58-driven senescence was strictly dependent on the presence of functional p53 as revealed by the fact that normal cells with p53 knockdown by specific shRNA or cells with a mutated or functionally impaired p53 pathway were effective in bypassing MSP58-induced senescence. At least two senescence mechanisms are induced by MSP58. First, MSP58 activates the DNA damage response and p53/p21 signaling pathways. Second, MSP58, p53, and the SWI/SNF chromatin-remodeling subunit Brahma-related gene 1 (BRG1) form a ternary complex on the p21 promoter and collaborate to activate p21. Additionally, MSP58 protein levels increased in cells undergoing replicative senescence and stress-induced senescence. Notably, the results of analyzing expression levels of MSP58 between tumors and matched normal tissues showed significant changes (both up- and down-regulation) in its expression in various types of tumors. Our findings highlight new aspects of MSP58 in modulating cellular senescence and suggest that MSP58 has both oncogenic and tumor-suppressive properties.

SUMOylated CPAP is required for IKK-mediated NF-κB activation and enhances HBx-induced NF-κB signaling in HCC.

BACKGROUND & AIMS: Constitutive activation of NF-κB is an important event involved in chronic inflammation in hepatocellular carcinoma (HCC). CPAP, which plays important roles in centrosomal functions, was previously identified as the transcriptional co-activator of NF-κB. However, the molecular mechanism is unclear. The goal of this study was to investigate the role of CPAP in activating the NF-κB pathway in HCC. METHODS: SK-Hep1, HuH7, HepG2, HepG2X, Hep3B, and Hep3BX cells with CPAP overexpression or CPAP siRNA were used to evaluate activation of NF-κB under TNF-α stimulation by reporter assay, RT-PCR, Q-PCR, and Western blot analysis. In vivo SUMO modification of CPAP was demonstrated by an in situ PLA assay. Human HCC tissues were used to perform Q-PCR, Western blot, and IHC. RESULTS: CPAP siRNA abolished the interaction between IKKß and NF-κB, whereas overexpression of CPAP enhanced this interaction and finally led to augmented NF-κB activation by increasing the phosphorylation of NF-κB. CPAP could enter nuclei by associating with NF-κB. Furthermore, CPAP was SUMO-1 modified upon TNF-α stimulus, and this is essential for its NF-κB co-activator activity. SUMO-1-deficient CPAP mutant lost its NF-κB co-activator activity and failed to enter nuclei. Importantly, SUMOylated CPAP could synergistically increase the HBx-induced NF-κB activity. CONCLUSIONS: CPAP is essential for the recruitment of the IKK complex to inactivated NF-κB upon TNF-α treatment. Expression of CPAP was positively correlated with a poor prognosis in HBV-HCC. CPAP has the potential to serve as a therapeutic target for inflammation and inflammation-related diseases.

Analysis of the interaction between Zinc finger protein 179 (Znf179) and promyelocytic leukemia zinc finger (Plzf).

BACKGROUND: Zinc finger protein 179 (Znf179), also known as ring finger protein 112 (Rnf112), is a member of the RING finger protein family and plays an important role in neuronal differentiation. To investigate novel mechanisms of Znf179 regulation and function, we performed a yeast two-hybrid screen to identify Znf179-interacting proteins. RESULTS: Using a yeast two-hybrid screen, we have identified promyelocytic leukemia zinc finger (Plzf) as a specific interacting protein of Znf179. Further analysis showed that the region containing the first two zinc fingers of Plzf is critical for its interaction with Znf179. Although the transcriptional regulatory activity of Plzf was not affected by Znf179 in the Gal4-dependent transcription assay system, the cellular localization of Znf179 was changed from cytoplasm to nucleus when Plzf was co-expressed. We also found that Znf179 interacted with Plzf and regulated Plzf protein expression. CONCLUSIONS: Our results showed that Znf179 interacted with Plzf, resulting in its translocation from cytoplasm to the nucleus and increase of Plzf protein abundance. Although the precise nature and role of the Znf179-Plzf interaction remain to be elucidated, both of these two genes are involved in the regulation of neurogenesis. Our finding provides further research direction for studying the molecular functions of Znf179.

Overexpression of interleukin-20 correlates with favourable prognosis in diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoma worldwide, accounting for about 40% of cases. The role of cytokines in the pathogenesis of lymphomas has been rarely addressed, although cytokines have a close immunological relationship with lymphocytes. We observed overexpression of interleukin (IL)-20 in reactive germinal centres (GCs) leading us to hypothesise that IL-20 may play a role in lymphomagenesis. In this study, we surveyed for IL-20 expression in various types of lymphoma and found that IL-20 was expressed most frequently in follicular lymphoma (94%), but also in Burkitt lymphoma (81%), mantle cell lymphoma (57%), nodal marginal zone lymphoma (56%), Hodgkin lymphomas (50%), small lymphocytic lymphoma (50%) and diffuse large B-cell lymphoma (DLBCL, 48%). IL-20 was not expressed in extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), lymphoplasmacytic lymphoma, and plasmacytoma. T-cell lymphomas were largely negative for IL-20 expression, except for anaplastic large cell lymphoma (ALCL, 61%), which frequently expressed IL-20, especially in cutaneous ALCL, and showed an inverse association with ALK expression (p=0.024). We further tested IL-20 expression in another large cohort of DLBCL and found IL-20 expression more frequently in germinal centre B-cell (GCB) than in non-GCB subtype [16/26 (62%) versus 24/64 (38%), p=0.038]. In this cohort, IL-20 was associated with a lower rate of extranodal involvement (p=0.009), bone marrow involvement (p=0.040), and better overall survival (p=0.020). Mechanistically, IL-20 overexpression promoted G1 cell cycle arrest and subsequent apoptosis of DLBCL cells and vice versa in vitro. We conclude that IL-20 may be involved in lymphomagenesis and may be useful as a prognostic marker in patients with DLBCL. In addition, IL-20 plays an inhibitory role in DLBCL growth, probably through cell cycle regulation.

CCAAT/enhancer-binding protein delta mediates tumor necrosis factor alpha-induced Aurora kinase C transcription and promotes genomic instability.

Epidemiologic and clinical research indicates that chronic inflammation increases the risk of certain cancers, possibly through chromosomal instability. However, the mechanism of inflammation-dependent chromosomal instability associated with tumorigenesis is not well characterized. The transcription factor CCAAT/enhancer-binding protein δ (C/EBPδ, CEBPD) is induced by tumor necrosis factor α (TNFα) and expressed in chronically inflamed tissue. In this study, we show that TNFα promotes aneuploidy. Loss of CEBPD attenuated TNFα-induced aneuploidy, and CEBPD caused centromere abnormality. Additionally, TNFα-induced CEBPD expression augmented anchorage-independent growth. We found that TNFα induced expression of aurora kinase C (AURKC) through CEBPD, and that AURKC also causes aneuploidy. Furthermore, high CEBPD expression correlated with AURKC expression in inflamed cervical tissue specimens. These data provide insight into a novel function for CEBPD in inducing genomic instability through the activation of AURKC expression in response to inflammatory signals.

Aberrantly expressed AURKC enhances the transformation and tumourigenicity of epithelial cells.

Over-expression of AURKC has been detected in human colorectal cancers, thyroid carcinoma and several cancer cell lines. However, the regulation and clinical implications of over-expressed AURKC in cancer cells are unclear. Here we show that elevated AURKC increases the proliferation, transformation and migration of cancer cells. Importantly, the kinase activity of AURKC is required for these tumour-associated properties. Analysis of human cancer specimens shows that the expression of AURKC is increased in cervical cancer, and is highly correlated with staging in colorectal cancer. Over-expressed AURKC-GFP localizes to the centromeric regions of mitotic chromosomes and results in a decreased level of AURKB, a key regulator of spindle checkpoint. Expression of AURKC is down-regulated by PLZF, a transcriptional repressor, through recruitment to its promoter region. The expression levels of PLZF and AURKC mRNA display opposite patterns in human cervical and colorectal cancers. Taken together, our results provide important insights into human cancers with AURKC expression, which may serve as a potential target for cancer therapy in the future.

Spatiotemporal gating of Stat nuclear influx by Drosophila Npas4 in collective cell migration.

Collective migration is important to embryonic development and cancer metastasis, but migratory and nonmigratory cell fate discrimination by differential activity of signal pathways remains elusive. In Drosophila oogenesis, Jak/Stat signaling patterns the epithelial cell fates in early egg chambers but later renders motility to clustered border cells. How Jak/Stat signal spatiotemporally switches static epithelia to motile cells is largely unknown. We report that a nuclear protein, Dysfusion, resides on the inner nuclear membrane and interacts with importin α/ß and Nup153 to modulate Jak/Stat signal by attenuating Stat nuclear import. Dysfusion is ubiquitously expressed in oogenesis but specifically down-regulated in border cells when migrating. Increase of nuclear Stat by Dysfusion down-regulation triggers invasive cell behavior and maintains persistent motility. Mammalian homolog of Dysfusion (NPAS4) also negatively regulates the nuclear accumulation of STAT3 and cancer cell migration. Thus, our finding demonstrates that Dysfusion-dependent gating mechanism is conserved and may serve as a therapeutic target for Stat-mediated cancer metastasis.

Disruption of the pentraxin 3/CD44 interaction as an efficient therapy for triple-negative breast cancers.

Due to the heterogeneity and high frequency of genome mutations in cancer cells, targeting vital protumour factors found in stromal cells in the tumour microenvironment may represent an ideal strategy in cancer therapy. However, the regulation and mechanisms of potential targetable therapeutic candidates need to be investigated. An in vivo study demonstrated that loss of pentraxin 3 (PTX3) in stromal cells significantly decreased the metastasis and growth of cancer cells. Clinically, our results indicate that stromal PTX3 expression correlates with adverse prognostic features and is associated with worse survival outcomes in triple-negative breast cancer (TNBC). We also found that transforming growth factor beta 1 (TGF-ß1) induces PTX3 expression by activating the transcription factor CCAAT/enhancer binding protein delta (CEBPD) in stromal fibroblasts. Following PTX3 stimulation, CD44, a PTX3 receptor, activates the downstream ERK1/2, AKT and NF-κB pathways to specifically contribute to the metastasis/invasion and stemness of TNBC MDA-MB-231 cells. Two types of PTX3 inhibitors were developed to disrupt the PTX3/CD44 interaction and they showed a significant effect on attenuating growth and restricting the metastasis/invasion of MDA-MB-231 cells, suggesting that targeting the PTX3/CD44 interaction could be a new strategy for future TNBC therapies.

The B56gamma3 regulatory subunit of protein phosphatase 2A (PP2A) regulates S phase-specific nuclear accumulation of PP2A and the G1 to S transition.

Protein phosphatase 2A (PP2A) is a heterotrimeric enzyme consisting of a scaffold subunit (A), a catalytic subunit (C), and a variable regulatory subunit (B). The regulatory B subunits determine the substrate specificity and subcellular localization of the PP2A holoenzyme. Here, we demonstrate that the subcellular localization of the B56gamma3 regulatory subunit is regulated in a cell cycle-specific manner. Notably, B56gamma3 becomes enriched in the nucleus at the G(1)/S border and in S phase. The S phase-specific nuclear enrichment of B56gamma3 is accompanied by increases of nuclear A and C subunits and nuclear PP2A activity. Overexpression of B56gamma3 promotes nuclear localization of the A and C subunits, whereas silencing both B56gamma2 and B56gamma3 blocks the S phase-specific increase in the nuclear localization and activity of PP2A. In NIH3T3 cells, B56gamma3 overexpression reduces p27 phosphorylation at Thr-187, concomitantly elevates p27 protein levels, delays the G(1) to S transition, and retards cell proliferation. Consistently, knockdown of endogenous B56gamma3 expression reduces p27 protein levels and increases cell proliferation in HeLa cells. These findings demonstrate that the dynamic nuclear distribution of the B56gamma3 regulatory subunit controls nuclear PP2A activity, which regulates cell cycle controllers, such as p27, to restrain cell cycle progression, and may be responsible for the tumor suppressor function of PP2A.

CPAP enhances and maintains chronic inflammation in hepatocytes to promote hepatocarcinogenesis.

Chronic and persistent inflammation is a well-known carcinogenesis promoter. Hepatocellular carcinoma (HCC) is one of the most common inflammation-associated cancers; most HCCs arise in the setting of chronic inflammation and hepatic injury. Both NF-κB and STAT3 are important regulators of inflammation. Centrosomal P4.1-associated protein (CPAP), a centrosomal protein that participates primarily in centrosome functions, is overexpressed in HCC and can increase TNF-α-mediated NF-κB activation and IL-6-induced STAT3 activation. A transgenic (Tg) mouse model with hepatocyte-specific CPAP expression was established to investigate the physiological role of CPAP in hepatocarcinogenesis. Obvious inflammatory cell accumulation and fatty change were observed in the livers of CPAP Tg mice. The alanine aminotransferase (ALT) level and the expression levels of inflammatory genes, such as IL-6, IL-1ß and TNF-α, were higher in CPAP Tg mice than in wild type (WT) mice. High-dose/short-term treatment with diethylnitrosamine (DEN) increased the ALT level, proinflammatory gene expression levels, and STAT3 and NF-κB activation in CPAP Tg mice; low-dose/long-term DEN treatment induced more severe liver tumor formation in CPAP Tg mice than in WT mice. CPAP can increase the expression of chemokine (C-C motif) ligand 16 (CCL-16), an important chemotactic cytokine, in human hepatocytes. CCL-16 expression is positively correlated with CPAP and TNF-α mRNA expression in the peritumoral part of HCC. In summary, these results suggest that CPAP may promote hepatocarcinogenesis through enhancing the inflammation pathway via increasing the expression of CCL-16.