Extracellular matrix marker LAMC2 targets ZEB1 to promote TNBC malignancy via up-regulating CD44/STAT3 signaling pathway.

BACKGROUND: Triple negative breast cancer (TNBC) is a heterogeneous and aggressive disease characterized by a high risk of mortality and poor prognosis. It has been reported that Laminin γ2 (LAMC2) is highly expressed in a variety of tumors, and its high expression is correlated with cancer development and progression. However, the function and mechanism by which LAMC2 influences TNBC remain unclear. METHODS: Kaplan-Meier survival analysis and Immunohistochemical (IHC) staining were used to examine the expression level of LAMC2 in TNBC. Subsequently, cell viability assay, wound healing and transwell assay were performed to detect the function of LAMC2 in cell proliferation and migration. A xenograft mouse model was used to assess tumorigenic function of LAMC2 in vivo. Luciferase reporter assay and western blot were performed to unravel the underlying mechanism. RESULTS: In this study, we found that higher expression of LAMC2 significantly correlated with poor survival in the TNBC cohort. Functional characterization showed that LAMC2 promoted cell proliferation and migration capacity of TNBC cell lines via up-regulating CD44. Moreover, LAMC2 exerted oncogenic roles in TNBC through modulating the expression of epithelial-mesenchymal transition (EMT) markers. Luciferase reporter assay verified that LAMC2 targeted ZEB1 to promote its transcription. Interestingly, LAMC2 regulated cell migration in TNBC via STAT3 signaling pathway. CONCLUSION: LAMC2 targeted ZEB1 via activating CD44/STAT3 signaling pathway to promote TNBC proliferation and migration, suggesting that LAMC2 could be a potential therapeutic target in TNBC patients.

Characterization of a germline variant TNS1 c.2999-1G > C in a hereditary cancer syndrome family.

Hereditary cancer syndromes result from the presence of inherited pathogenic variants within susceptibility genes. However, the susceptibility genes associated with hereditary cancer syndrome remain predominantly unidentified. Here, we reported a case of hereditary cancer syndrome observed in a Chinese family harboring a germline mutation in Tensin1 (TNS1). We described a 59-year-old female patient presented with Multiple myeloma and Thyroid carcinoma. The proband and her family members exhibited suspected tumor syndrome due to occurrences of other cancer cases. After oncogenetic counseling, whole-exome sequencing and Sanger sequencing were conducted and a primary driver mutation of TNS1 (NM_022648.7:c.2999-1G > C) was detected. Gene Expression Profiling Interactive Analysis revealed that TNS1 was expressed lower in different tumors when compared to normal, including Pancreatic adenocarcinoma, Breast invasive carcinoma, Thyroid carcinoma andColon adenocarcinoma cells. Despite the well-established role of TNS1 as a tumor suppressor in breast cancer and colorectal cancer, its potential utility as a marker gene for diagnosis and treatment of pancreatic cancer remains uncertain. Here, our data demonstrated that knockdown of TNS1 could promote cell proliferation and migration in Pancreatic adenocarcinoma (PDAC) cells. In addition, TNS1 regulated migration through EMT signaling pathway in PDAC cells. Our findings proposed that this variant was likely involved in cancer predisposition by disrupting the normal splicing process. In summary, we presented a genetic disease by linking an intronic mutation inTNS1. We aim to provide early detection of cancers by identifying germline variants in susceptibility genes.

Targeting C21orf58 is a Novel Treatment Strategy of Hepatocellular Carcinoma by Disrupting the Formation of JAK2/C21orf58/STAT3 Complex.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. Functionally uncharacterized genes are an attractive repository to explore candidate oncogenes. It is demonstrated that C21orf58 displays an oncogenic role in promoting cell growth, tumorigenesis and sorafenib resistance of HCC cells by abnormal activation of STAT3 signaling. Mechanistically, a novel manner to regulate STAT3 signaling that adaptor C21orf58 forms a ternary complex is reveal with N-terminal domain of STAT3 and SH2 domain of JAK2, by which C21orf58 overactivates wild-type STAT3 by facilitating its phosphorylation mediated by JAK2, and hyper-activates of constitutively mutated STAT3 due to preferred binding with C21orf58 and JAK2. Moreover, it is validated that inhibition of C21orf58 with drug alminoprofen, selected by virtual screening, could effectively repress the viability and tumorigenesis of HCC cells. Therefore, it is identified that C21orf58 functions as an oncogenic adaptor, reveal a novel regulatory mechanism of JAK2/STAT3 signaling, explain the cause of abnormal activity of activated mutants of STAT3, and explore the attractive therapeutic potential by targeting C21orf58 in HCC.

Therapeutic potential of anti-PIK3CG treatment for multiple myeloma via inhibiting c-Myc pathway.

Multiple myeloma (MM) is a malignant plasma cell disease. The activity of PIK3CG (PI3K catalytic subunit γ) is regulated directly by G-protein-coupled receptor and has been confirmed to be highly expressed in MM cells. This study aimed to determine the effect of pharmacological inhibition of PIK3CG on MM. We found that different concentrations of the PIK3CG inhibitor AS-605240 could suppress the growth of MM cell lines and the expression of c-Myc. The combination of PIK3CG inhibitor and the chemotherapy Melphalan could effectively inhibit the proliferation and migration of MM cells, promote the cell apoptosis, and decrease the ratio of Bcl-2/Bax and the expression of vimentin. The expression of proto-oncogene c-Myc was decreased and the sensitivity of cells to chemotherapeutic drugs was enhanced. Collectively, PIK3CG regulates growth of MM via c-Myc pathway, thus emerging as a promising molecular targeted therapy.

Deubiquitinase OTUD3: a double-edged sword in immunity and disease.

Deubiquitination is an important form of post-translational modification that regulates protein homeostasis. Ovarian tumor domain-containing proteins (OTUDs) subfamily member OTUD3 was identified as a deubiquitinating enzyme involved in the regulation of various physiological processes such as immunity and inflammation. Disturbances in these physiological processes trigger diseases in humans and animals, such as cancer, neurodegenerative diseases, diabetes, mastitis, etc. OTUD3 is aberrantly expressed in tumors and is a double-edged sword, exerting tumor-promoting or anti-tumor effects in different types of tumors affecting cancer cell proliferation, metastasis, and metabolism. OTUD3 is regulated at the transcriptional level by a number of MicroRNAs, such as miR-520h, miR-32, and miR101-3p. In addition, OTUD3 is regulated by a number of post-translational modifications, such as acetylation and ubiquitination. Therefore, understanding the regulatory mechanisms of OTUD3 expression can help provide insight into its function in human immunity and disease, offering the possibility of its use as a therapeutic target to diagnose or treat disease.

A novel RBBP8(p.E281*) germline mutation is a predisposing mutation in familial hereditary cancer syndrome.

Screening tumor susceptibility genes helps in identifying powerful biomarkers for hereditary cancer monitoring, prevention, and diagnosis, providing opportunities for understanding potential molecular mechanisms and biomarkers for the precise treatment of hereditary cancer syndromes. Whole-exome sequencing of blood and bioinformatics analysis uncovered a novel RBBP8(p.E281*) germline mutation in a family with hereditary cancer syndrome, which was verified by Sanger sequencing. Cell proliferation, colony formation, cell migration, and in vivo tumorigenesis were investigated by CCK8, colony formation, Transwell, and in vivo xenograft assays. Protein localization and interaction were detected by immunofluorescence, nuclear and cytoplasmic protein extraction kits, and Co-IP. A new heterozygous germline mutation of the RBBP8(p.E281*) gene was found to be associated with familial hereditary cancer syndrome. RBBP8-WT was mainly detected in the nucleus and interacts with BRCA1. In contrast, RBBP8(p.E281*) is mainly located in the cytoplasm, with no interaction with BRCA1. RBBP8(p.E281*) variant plays an oncogenic role in the cytoplasm in addition to its loss of function in the nucleus, which promotes breast cancer proliferation, in vivo tumorigenesis, and migration. Compared with the control group, RBBP8(p.E281*) showed elevated cell death in response to cisplatin and olaparib treatment. A novel RBBP8(p.E281*) germline mutation was identified from familial hereditary cancer syndrome. RBBP8(p.E281*) is not able to enter the nucleus or interact with BRCA1 through the lost binding motif, and RBBP8(p.E281*) variant appears to promote tumorigenesis in the cytoplasm in addition to its loss of function in the nucleus. RBBP8(p.E281*) variant may promote tumor susceptibility and serve as a precision medicine biomarker in familial hereditary cancer syndrome. KEY MESSAGES: RBBP8(p.E281*) is a susceptibility gene in this familial hereditary cancer syndrome RBBP8(p.E281*) lost its ability to enter the nucleus and the BRCA1 binding motif A novel RBBP8(p.E281*) germline mutation promotes breast cancer tumorigenesis Patients with RBBP8(p.E281*) germline mutation may benefit from Olaparib, Cisplatin.

The role of zinc finger proteins in malignant tumors.

Zinc finger proteins (ZNFs) are the largest family of transcriptional factors in mammalian cells. Recently, their role in the development, progression, and metastasis of malignant tumors via regulating gene transcription and translation processes has become evident. Besides, their possible involvement in drug resistance has also been found, indicating that ZNFs have the potential to become new biological markers and therapeutic targets. In this review, we summarize the oncogenic and suppressive roles of various ZNFs in malignant tumors, including lung, breast, liver, gastric, colorectal, pancreatic, and other cancers, highlighting their role as prognostic markers, and hopefully provide new ideas for the treatment of malignant tumors in the future.

Dissected subgroups predict the risk of recurrence of stage II colorectal cancer and select rational treatment.

Background: Stage II colorectal cancer(CRC) patients after surgery alone have a five-year survival rate of ~60-80%; the incremental benefit of adjuvant chemotherapy is <5%. Predicting risk of recurrence and selecting effective personalized adjuvant drugs for stage II CRC using formalin-fixed, paraffin-embedded(FFPE) samples is a major challenge. Methods: 1319 stage II CRC patients who enrolled in 2011-2019 at Sun Yat-sen University Cancer Center were screened. RNAseq data of FFPE tumor samples of 222 stage II microsatellite stable(MSS) CRC patients(recurrence (n=47), norecurrence (n=175), median follow-up=41 months) were used to develop a method TFunctionalProg for dissecting heterogeneous subgroups of recurrence and predicting risk of recurrence. Results: TFunctionalProg showed significant predictive values in 222 stage II MSS CRCs. The TFunctionalProg low-risk group had significantly better recurrence free survival (validation set: HR=4.78, p-value=1e-4, low-risk group three-year recurrence free survival=92.6%, high-risk group three-year recurrence free survival=59.7%). TFunctionalProg dissected two subgroups of transition states of stage II MSS CRCs at a high risk of recurrence; each state displays distinct levels of hybrid epithelial-mesenchymal traits, CD8+ T cell suppression mechanisms and FOLFOX resistance. Based on mechanisms in two subgroups, TFunctionalProg proposed personalized rational adjuvant drug combinations of immunotherapy, chemotherapy and repurposed CNS drugs. TFunctionalProg provides different utilities from ctDNA-based prognostic biomarkers. Conclusion: TFunctionalProg was validated using FFPE samples to predict the risk of recurrence and propose rational adjuvant drug combinations for stage II CRC.

Upregulated GATA3/miR205-5p Axis Inhibits MFNG Transcription and Reduces the Malignancy of Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) accounts for approximately 20% of all breast carcinomas and has the worst prognosis of all breast cancer subtypes due to the lack of an effective target. Therefore, understanding the molecular mechanism underpinning TNBC progression could explore a new target for therapy. While the Notch pathway is critical in the development process, its dysregulation leads to TNBC initiation. Previously, we found that manic fringe (MFNG) activates the Notch signaling and induces breast cancer progression. However, the underlying molecular mechanism of MFNG upstream remains unknown. In this study, we explore the regulatory mechanisms of MFNG in TNBC. We show that the increased expression of MFNG in TNBC is associated with poor clinical prognosis and significantly promotes cell growth and migration, as well as Notch signaling activation. The mechanistic studies reveal that MFNG is a direct target of GATA3 and miR205-5p and demonstrate that GATA3 and miR205-5p overexpression attenuate MFNG oncogenic effects, while GATA3 knockdown mimics MFNG phenotype to promote TNBC progression. Moreover, we illustrate that GATA3 is required for miR205-5p activation to inhibit MFNG transcription by binding to the 3' UTR region of its mRNA, which forms the GATA3/miR205-5p/MFNG feed-forward loop. Additionally, our in vivo data show that the miR205-5p mimic combined with polyetherimide-black phosphorus (PEI-BP) nanoparticle remarkably inhibits the growth of TNBC-derived tumors which lack GATA3 expression. Collectively, our study uncovers a novel GATA3/miR205-5p/MFNG feed-forward loop as a pathway that could be a potential therapeutic target for TNBC.

Fringe family genes and their modulation of Notch signaling in cancer.

Fringes are glycosyltransferases that transfer N-acetylglucosamine to the O-linked fucose of Notch receptors. They regulate the Notch signaling activity that drives tumor formation and progression, resulting in poor prognosis. However, the specific tumor-promoting role of Fringes differs depending on the type of cancer. Although a particular Fringe member could act as a tumor suppressor in one cancer type, it may act as an oncogene in another. This review discusses the tumorigenic role of the Fringe family (lunatic fringe, manic fringe, and radical fringe) in modulating Notch signaling in various cancers. Although the crucial functions of Fringes continue to emerge as more mechanistic studies are being pursued, further translational research is needed to explore their roles and therapeutic benefits in various malignancies.

Structure-function analysis of the Fusarium oxysporum Avr2 effector allows uncoupling of its immune-suppressing activity from recognition.

Plant pathogens employ effector proteins to manipulate their hosts. Fusarium oxysporum f. sp. lycopersici (Fol), the causal agent of tomato wilt disease, produces effector protein Avr2. Besides being a virulence factor, Avr2 triggers immunity in I-2 carrying tomato (Solanum lycopersicum). Fol strains that evade I-2 recognition carry point mutations in Avr2 (e.g. Avr2R45H ), but retain full virulence. Here we investigate the virulence function of Avr2 and determine its crystal structure. Transgenic tomato and Arabidopsis expressing either wild-type ΔspAvr2 (deleted signal-peptide) or the ΔspAvr2R45H variant become hypersusceptible to fungal, and even bacterial infections, suggesting that Avr2 targets a conserved defense mechanism. Indeed, Avr2 transgenic plants are attenuated in immunity-related readouts, including flg22-induced growth inhibition, ROS production and callose deposition. The crystal structure of Avr2 reveals that the protein shares intriguing structural similarity to ToxA from the wheat pathogen Pyrenophora tritici-repentis and to TRAF proteins. The I-2 resistance-breaking Avr2V41M , Avr2R45H and Avr2R46P variants cluster on a surface-presented loop. Structure-guided mutagenesis enabled uncoupling of virulence from I-2-mediated recognition. We conclude that I-2-mediated recognition is not based on monitoring Avr2 virulence activity, which includes suppression of immune responses via an evolutionarily conserved effector target, but by recognition of a distinct epitope.

Involvement of salicylic acid, ethylene and jasmonic acid signalling pathways in the susceptibility of tomato to Fusarium oxysporum.

Phytohormones, such as salicylic acid (SA), ethylene (ET) and jasmonic acid (JA), play key roles in plant defence following pathogen attack. The involvement of these hormones in susceptibility following Fusarium oxysporum (Fo) infection has mostly been studied in Arabidopsis thaliana. However, Fo causes vascular wilt disease in a broad range of crops, including tomato (Solanum lycopersicum). Surprisingly little is known about the involvement of these phytohormones in the susceptibility of tomato towards Fo f. sp. lycopersici (Fol). Here, we investigate their involvement by the analysis of the expression of ET, JA and SA marker genes following Fol infection, and by bioassays of tomato mutants affected in either hormone production or perception. Fol inoculation triggered the expression of SA and ET marker genes, showing the activation of these pathways. NahG tomato, in which SA is degraded, became hypersusceptible to Fol infection and showed stronger disease symptoms than wild-type. In contrast, ACD and Never ripe (Nr) mutants, in which ET biosynthesis and perception, respectively, are impaired, showed decreased disease symptoms and reduced fungal colonization on infection. The susceptibility of the def1 tomato mutant, and a prosystemin over-expressing line, in which JA signalling is compromised or constitutively activated, respectively, was unaltered. Our results show that SA is a negative and ET a positive regulator of Fol susceptibility. The SA and ET signalling pathways appear to act synergistically, as an intact ET pathway is required for the induction of an SA marker gene, and vice versa.

How Phytohormones Shape Interactions between Plants and the Soil-Borne Fungus Fusarium oxysporum.

Plants interact with a huge variety of soil microbes, ranging from pathogenic to mutualistic. The Fusarium oxysporum (Fo) species complex consists of ubiquitous soil inhabiting fungi that can infect and cause disease in over 120 different plant species including tomato, banana, cotton, and Arabidopsis. However, in many cases Fo colonization remains symptomless or even has beneficial effects on plant growth and/or stress tolerance. Also in pathogenic interactions a lengthy asymptomatic phase usually precedes disease development. All this indicates a sophisticated and fine-tuned interaction between Fo and its host. The molecular mechanisms underlying this balance are poorly understood. Plant hormone signaling networks emerge as key regulators of plant-microbe interactions in general. In this review we summarize the effects of the major phytohormones on the interaction between Fo and its diverse hosts. Generally, Salicylic Acid (SA) signaling reduces plant susceptibility, whereas Jasmonic Acid (JA), Ethylene (ET), Abscisic Acid (ABA), and auxin have complex effects, and are potentially hijacked by Fo for host manipulation. Finally, we discuss how plant hormones and Fo effectors balance the interaction from beneficial to pathogenic and vice versa.

Uptake of the Fusarium Effector Avr2 by Tomato Is Not a Cell Autonomous Event.

Pathogens secrete effector proteins to manipulate the host for their own proliferation. Currently it is unclear whether the uptake of effector proteins from extracellular spaces is a host autonomous process. We study this process using the Avr2 effector protein from Fusarium oxysporum f. sp. lycopersici (Fol). Avr2 is an important virulence factor that is secreted into the xylem sap of tomato following infection. Besides that, it is also an avirulence factor triggering immune responses in plants carrying the I-2 resistance gene. Recognition of Avr2 by I-2 occurs inside the plant nucleus. Here, we show that pathogenicity of an Avr2 knockout Fusarium (FolΔAvr2) strain is fully complemented on transgenic tomato lines that express either a secreted (Avr2) or cytosolic Avr2 (ΔspAvr2) protein, indicating that Avr2 exerts its virulence functions inside the host cells. Furthermore, our data imply that secreted Avr2 is taken up from the extracellular spaces in the presence of the fungus. Grafting studies were performed in which scions of I-2 tomato plants were grafted onto either a ΔspAvr2 or on an Avr2 rootstock. Although the Avr2 protein could readily be detected in the xylem sap of the grafted plant tissues, no I-2-mediated immune responses were induced suggesting that I-2-expressing tomato cells cannot autonomously take up the effector protein from the xylem sap. Additionally, ΔspAvr2 and Avr2 plants were crossed with I-2 plants. Whereas ΔspAvr2/I-2 F1 plants showed a constitutive immune response, immunity was not triggered in the Avr2/I-2 plants confirming that Avr2 is not autonomously taken up from the extracellular spaces to trigger I-2. Intriguingly, infiltration of Agrobacterium tumefaciens in leaves of Avr2/I-2 plants triggered I-2 mediated cell death, which indicates that Agrobacterium triggers effector uptake. To test whether, besides Fol, effector uptake could also be induced by other fungal pathogens the ΔspAvr2 and Avr2 transgenic lines were inoculated with Verticillium dahliae. Whereas ΔspAvr2 plants became hyper-susceptible to infection, no difference in disease development was found in the Avr2 plants as compared to wild-type plants. These data suggest that effector uptake is not a host autonomous process and that Fol and A. tumefaciens, but not V. dahliae, facilitate Avr2 uptake by tomato cells from extracellular spaces.

Development and function of central cell in angiosperm female gametophyte.

The central cell characterizes the angiosperm female gametophyte (embryo sac or megagametophyte) in that it directly participates in "double fertilization" to initiate endosperm development, a feature distinguishing angiosperm from all other plant taxa. Polygonum-type central cell is a binucleate cell that, upon fertilization with one of the two sperm cells, forms triploid endosperm to nourish embryo development. Although the formation and the structure of central cell have well been elucidated, the molecular mechanisms for its specification and development remain largely unknown. The central cell plays a critical role in pollen tube guidance during pollination and in endosperm initiation after fertilization. Recently, a group of mutants affecting specific steps of central cell development and function have been identified, providing some clues in understanding these questions. This review summarizes our current knowledge about central cell development and function, and presents overview about hypotheses for its evolution.