NPM-ALK phosphorylates WASp Y102 and contributes to oncogenesis of anaplastic large cell lymphoma

LINC00869 Promotes Hepatocellular Carcinoma Metastasis via Protrusion Formation

Coordination of filament assembly and membrane remodeling is required for the directional migration of cancer cells. The Wiskott-Aldrich syndrome protein (WASP) recruits the actin-related protein (ARP) 2/3 complex to assemble branched actin networks. The goal of our study was to assess the potential regulatory role exerted by the novel long noncoding RNA (lncRNA) LINC00869 on hepatocellular carcinoma (HCC) cells. We used HCC cells to overexpress or knockdown LINC00869, analyzed patient data from publicly available databases and Cancer Hospital Affiliated with Zhengzhou University, and used a xenograft mouse model of HCC to study the molecular mechanism associated with LINC00869 expression. We found that high levels of LINC00869 expression were associated with poor prognosis in patients with HCC. Next, we detected an interaction between LINC00869 and both WASP and ARP2 in HCC cells, and observed a modulatory effect of LINC00869 on the phosphorylation of WASP at Y291 and the activity of cell division control protein 42 (CDC42). These modulatory roles were required for WASP/CDC42 activity on F-actin polymerization to enhance membrane protrusion formation and maintain persistent cell polarization. This, in turn, promoted the migration and invasion abilities of HCC cells. Finally, we confirmed the role of LINC00869in vivo, using the tumor xenograft mouse model; and identified a positive correlation between LINC00869 expression levels and the phosphorylation levels of WASP in HCC samples. Overall, our findings suggest a unique mechanism by which LINC00869 orchestrates membrane protrusion during migration and invasion of HCC cells.

IMPLICATIONS

LncRNA LINC00869 regulates the activity of CDC42-WASP pathway and positively affects protrusion formation in HCC cells, which expands the current understanding of lncRNA functions as well as gives a better understanding of carcinogenesis.

NPM3 as an Unfavorable Prognostic Biomarker Involved in Oncogenic Pathways of Lung Adenocarcinoma via MYC Translational Activation

BACKGROUND

The nucleoplasmin/nucleophosmin (NPM) family was previously regarded as a critical regulator during disease development, and its mediation in carcinogenesis has achieved intensive attention recently. However, the clinical importance and functional mechanism of NPM3 in lung adenocarcinoma (LUAD) have not been reported yet.

OBJECTIVE

This study aimed to investigate the role and clinical significance of NPM3 in the development and progression of LUAD, including the underlying mechanisms.

METHODS

The expression of NPM3 in pan-cancer was analyzed via GEPIA. The effect of NPM3 on prognosis was analyzed by the Kaplan-Meier plotter and the PrognoScan database. In vitro, cell transfection, RT-qPCR, CCK-8 assay, and wound healing assay were employed to examine the role of NPM3 in A549 and H1299 cells. Gene set enrichment analysis (GSEA) was performed using the R software package to analyze the tumor hallmark pathway and KEGG pathway of NPM3. The transcription factors of NPM3 were predicted based on the ChIP-Atlas database. Dual-luciferase reporter assay was applied to verify the transcriptional regulatory factor of the NPM3 promoter region.

RESULTS

The NPM3 expression was found to be markedly higher in the LUAD tumor group than the normal group and to be positively correlated with poor prognosis, tumor stages, and radiation therapy. In vitro, the knockdown of NPM3 greatly inhibited the proliferation and migration of A549 and H1299 cells. Mechanistically, GSEA predicted that NPM3 activated the oncogenic pathways. Further, the NPM3 expression was found to be positively correlated with cell cycle, DNA replication, G2M checkpoint, HYPOXIA, MTORC1 signaling, glycolysis, and MYC targets. Besides, MYC targeted the promoter region of NPM3 and contributed to the enhanced expression of NPM3 in LUAD.

CONCLUSION

The overexpression of NPM3 is an unfavorable prognostic biomarker participating in oncogenic pathways of LUAD via MYC translational activation and it contributes to tumor progression. Thus, NPM3 could be a novel target for LUAD therapy.

SOHO State of the Art Updates and Next Questions | New Pathways and New Targets in PTCL: Staying on Target

While the peripheral T-cell lymphomas (PTCL) remain a therapeutic challenge, and increasingly account for a disproportionate number of lymphoma-related deaths, improved understanding of disease pathogenesis and classification, and the development of novel therapeutic agents over the past decade, all provide reasons for a more optimistic outlook in the next. Despite their genetic and molecular heterogeneity, many PTCL are dependent upon signaling input provided by antigen, costimulatory, and cytokine receptors. While gain-of-function alterations effecting these pathways are recurrently observed in many PTCL, more often than not, signaling remains ligand-and tumor microenvironment (TME)-dependent. Consequently, the TME and its constituents are increasingly recognized as "on target". Utilizing a "3 signal" model, we will review new-and old-therapeutic targets that are relevant for the more common nodal PTCL subtypes.

Classification and challenges in the histopathological diagnosis of peripheral T-cell lymphomas, emphasis on the WHO-HAEM5 updates

Mature T-cell lymphomas represent neoplastic expansions of T-cell lymphocytes with a post-thymic derivation. Most of these tumors feature aggressive clinical behavior and challenging histopathological diagnosis and classification. Novel findings in the genomic landscape of T-cell lymphomas are helping to improve the understanding of the biology and the molecular mechanisms that underly its clinical behavior. The most recent WHO-HAEM5 classification of hematolymphoid tumors introduced novel molecular and histopathological findings that will aid in the diagnostic classification of this group of neoplasms. The current review article summarizes the most relevant diagnostic features of peripheral T-cell lymphomas with an emphasis on the updates that are incorporated at the WHO-HAEM5.

WASP family proteins: Molecular mechanisms and implications in human disease

Proteins of the Wiskott-Aldrich syndrome protein (WASP) family play a central role in regulating actin cytoskeletal dynamics in a wide range of cellular processes. Genetic mutations or misregulation of these proteins are tightly associated with many diseases. The WASP-family proteins act by transmitting various upstream signals to their conserved WH2-Central-Acidic (WCA) peptide sequence at the C-terminus, which in turn binds to the Arp2/3 complex to stimulate the formation of branched actin networks at membranes. Despite this common feature, the regulatory mechanisms and cellular functions of distinct WASP-family proteins are very different. Here, we summarize and clarify our current understanding of WASP-family proteins and how disruption of their functions is related to human disease.

Holistic View of ALK TKI Resistance in ALK-Positive Anaplastic Large Cell Lymphoma

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase expressed at early stages of normal development and in various cancers including ALK-positive anaplastic large cell lymphoma (ALK+ ALCL), in which it is the main therapeutic target. ALK tyrosine kinase inhibitors (ALK TKIs) have greatly improved the prognosis of ALK+ALCL patients, but the emergence of drug resistance is inevitable and limits the applicability of these drugs. Although various mechanisms of resistance have been elucidated, the problem persists and there have been relatively few relevant clinical studies. This review describes research progress on ALK+ ALCL including the application and development of new therapies, especially in relation to drug resistance. We also propose potential treatment strategies based on current knowledge to inform the design of future clinical trials.

Targeting the actin nucleation promoting factor WASp provides a therapeutic approach for hematopoietic malignancies

Cancer cells depend on actin cytoskeleton rearrangement to carry out hallmark malignant functions including activation, proliferation, migration and invasiveness. Wiskott–Aldrich Syndrome protein (WASp) is an actin nucleation-promoting factor and is a key regulator of actin polymerization in hematopoietic cells. The involvement of WASp in malignancies is incompletely understood. Since WASp is exclusively expressed in hematopoietic cells, we performed in silico screening to identify small molecule compounds (SMCs) that bind WASp and promote its degradation. We describe here one such identified molecule; this WASp-targeting SMC inhibits key WASp-dependent actin processes in several types of hematopoietic malignancies in vitro and in vivo without affecting naïve healthy cells. This small molecule demonstrates limited toxicity and immunogenic effects, and thus, might serve as an effective strategy to treat specific hematopoietic malignancies in a safe and precisely targeted manner.

Cancer cells proliferate and invade via cytoskeletal proteins such as WASp, exclusively expressed in hematopoietic cells. Here the authors show a specific small molecule compound inhibiting cancer cell activity by WASp degradation and demonstrating its therapeutic potential in vitro and in vivo.

Cytoskeleton Dynamics in Peripheral T Cell Lymphomas: An Intricate Network Sustaining Lymphomagenesis

Defects in cytoskeleton functions support tumorigenesis fostering an aberrant proliferation and promoting inappropriate migratory and invasive features. The link between cytoskeleton and tumor features has been extensively investigated in solid tumors. However, the emerging genetic and molecular landscape of peripheral T cell lymphomas (PTCL) has unveiled several alterations targeting structure and function of the cytoskeleton, highlighting its role in cell shape changes and the aberrant cell division of malignant T cells. In this review, we summarize the most recent evidence about the role of cytoskeleton in PTCLs development and progression. We also discuss how aberrant signaling pathways, like JAK/STAT3, NPM-ALK, RhoGTPase, and Aurora Kinase, can contribute to lymphomagenesis by modifying the structure and the signaling properties of cytoskeleton.

Deficiency of Wiskott-Aldrich syndrome protein has opposing effect on the pro-oncogenic pathway activation in nonmalignant versus malignant lymphocytes

Immunodeficiency is associated with cancer risk. Accordingly, hematolymphoid cancers develop in Wiskott-Aldrich syndrome (WAS), an X-linked primary immunodeficiency disorder (PID) resulting from the deficiency of WAS-protein (WASp) expressed predominantly in the hematolymphoid cell lineages. Despite the correlation between WASp deficiency and hematolymphoid cancers, the molecular mechanism underlying the oncogenic role of WASp is incompletely understood. Employing the WASp-sufficient and WASp-deficient cell-pair model of human T and B lymphocytes, we show that WASp deficiency differentially influences hyperactivation versus inhibition of both CDC42:ERK1/2 and NF-κB:AP-1 pro-oncogenic signaling pathways in nonmalignant versus malignant T and B lymphocytes. Furthermore, WASp deficiency induces a cell-type specific up/down-modulation of the DNA-binding activities of NF-κB, AP-1, and multiple other transcription factors with known roles in oncogenesis. We propose that WASp functions as a putative "tumor-suppressor" protein in normal T and B cells, and "oncoprotein" in a subset of established T and B cell malignancies that are not associated with the NPM-ALK fusion.

Actin regulators in cancer progression and metastases: From structure and function to cytoskeletal dynamics

The cytoskeleton is a central factor contributing to various hallmarks of cancer. In recent years, there has been increasing evidence demonstrating the involvement of actin regulatory proteins in malignancy, and their dysregulation was shown to predict poor clinical prognosis. Although enhanced cytoskeletal activity is often associated with cancer progression, the expression of several inducers of actin polymerization is remarkably reduced in certain malignancies, and it is not completely clear how these changes promote tumorigenesis and metastases. The complexities involved in cytoskeletal induction of cancer progression therefore pose considerable difficulties for therapeutic intervention; it is not always clear which cytoskeletal regulator should be targeted in order to impede cancer progression, and whether this targeting may inadvertently enhance alternative invasive pathways which can aggravate tumor growth. The entire constellation of cytoskeletal machineries in eukaryotic cells are numerous and complex; the system is comprised of and regulated by hundreds of proteins, which could not be covered in a single review. Therefore, we will focus here on the actin cytoskeleton, which encompasses the biological machinery behind most of the key cellular functions altered in cancer, with specific emphasis on actin nucleating factors and nucleation-promoting factors. Finally, we discuss current therapeutic strategies for cancer which aim to target the cytoskeleton.

Colony-Stimulating Factor 1 Receptor (CSF1R) Activates AKT/mTOR Signaling and Promotes T-Cell Lymphoma Viability

PURPOSE

Peripheral T-cell lymphomas are clinically aggressive and usually fatal, as few complete or durable remissions are achieved with currently available therapies. Recent evidence supports a critical role for lymphoma-associated macrophages during T-cell lymphoma progression, but the specific signals involved in the cross-talk between malignant T cells and their microenvironment are poorly understood. Colony-stimulator factor 1 receptor (CSF1R, CD115) is required for the homeostatic survival of tissue-resident macrophages. Interestingly, its aberrant expression has been reported in a subset of tumors. In this article, we evaluated its expression and oncogenic role in T-cell lymphomas.

EXPERIMENTAL DESIGN

Loss-of-function studies, including pharmacologic inhibition with a clinically available tyrosine kinase inhibitor, pexidartinib, were performed in multiple in vitro and in vivo models. In addition, proteomic and genomic screenings were performed to discover signaling pathways that are activated downstream of CSF1R signaling.

RESULTS

We observed that CSF1R is aberrantly expressed in many T-cell lymphomas, including a significant number of peripheral and cutaneous T-cell lymphomas. Colony-stimulating factor 1 (CSF1), in an autocrine or paracrine-dependent manner, leads to CSF1R autophosphorylation and activation in malignant T cells. Furthermore, CSF1R signaling was associated with significant changes in gene expression and in the phosphoproteome, implicating PI3K/AKT/mTOR in CSF1R-mediated T-cell lymphoma growth. We also demonstrated that inhibition of CSF1R in vivo and in vitro models is associated with decreased T-cell lymphoma growth.

CONCLUSIONS

Collectively, these findings implicate CSF1R in T-cell lymphomagenesis and have significant therapeutic implications.

Wiskott-Aldrich syndrome protein (WASP) is a tumor suppressor in T cell lymphoma

In T lymphocytes, the Wiskott-Aldrich Syndrome protein (WASP) and WASP-interacting-protein (WIP) regulate T cell antigen receptor (TCR) signaling, but their role in lymphoma is largely unknown. Here we show that the expression of WASP and WIP is frequently low or absent in anaplastic large cell lymphoma (ALCL) compared to other T cell lymphomas. In anaplastic lymphoma kinase-positive (ALK+) ALCL, WASP and WIP expression is regulated by ALK oncogenic activity via its downstream mediators STAT3 and C/EBP-β. ALK+ lymphomas were accelerated in WASP- and WIP-deficient mice. In the absence of WASP, active GTP-bound CDC42 was increased and the genetic deletion of one CDC42 allele was sufficient to impair lymphoma growth. WASP-deficient lymphoma showed increased mitogen-activated protein kinase (MAPK) pathway activation that could be exploited as a therapeutic vulnerability. Our findings demonstrate that WASP and WIP are tumor suppressors in T cell lymphoma and suggest that MAP-kinase kinase (MEK) inhibitors combined with ALK inhibitors could achieve a more potent therapeutic effect in ALK+ ALCL.

From Pathology to Precision Medicine in Anaplastic Large Cell Lymphoma Expressing Anaplastic Lymphoma Kinase (ALK+ ALCL)

Anaplastic large cell lymphoma expressing anaplastic lymphoma kinase (ALK+ ALCL) is a distinct subtype of non-Hodgkin lymphoma. In this review, we discuss the historical findings that led to its classification as a unique disease, despite its varied clinical presentation and histology. We discuss the molecular mechanisms underlying ALK+ ALCL pathology and the questions that remain in the field. Finally, we visit how decades of ALK+ ALCL research has yielded more precise drugs that hold promise for the future.

Pyrimidine tract-binding protein 1 mediates pyruvate kinase M2-dependent phosphorylation of signal transducer and activator of transcription 3 and oncogenesis in anaplastic large cell lymphoma

PKM2 (pyruvate kinase M2), a critical regulator of glycolysis, is phosphorylated by numerous growth factor receptors and oncogenic tyrosine kinases including NPM-ALK which is expressed in a subset of aggressive T-cell non-Hodgkin lymphomas known as anaplastic large cell lymphoma, ALK-positive. Our previous work demonstrated that phosphorylation of Y105-PKM2 by NPM-ALK regulates a major metabolic shift to promote lymphomagenesis. In addition to its role in metabolism, recent studies have shown that PKM2 promotes oncogenesis by phosphorylating nuclear STAT3 (signal transducer and activator of transcription 3) and regulating transcription of genes involved in cell survival and proliferation. We hypothesized that identification of novel PKM2 interactors could provide additional insights into its expanding functional role in cancer. To this end, immunocomplexes of FLAG-tagged PKM2 were isolated from NPM-ALK-positive ALCL (anaplastic large cell lymphoma) cells and subjected to liquid chromatography tandem mass spectrometry (LC-MS/MS) which led to the identification of polypyrimidine tract-binding protein (PTBP1) as a novel interactor of PKM2. The interaction between PTBP1 and PKM2 was restricted to the nucleus and was dependent on NPM-ALK mediated Y105 phosphorylation of PKM2. Stable shRNA-mediated silencing of PTBP1 resulted in a marked decrease in pY105-PKM2 and pY705-STAT3 which led to decreased ALCL cell proliferation and colony formation. Overall, our data demonstrate that PTBP1 interacts with PKM2 and promotes ALCL oncogenesis by facilitating PKM2-dependent activation of STAT3 within the nucleus.

The second-generation ALK inhibitor alectinib effectively induces apoptosis in human neuroblastoma cells and inhibits tumor growth in a TH-MYCN transgenic neuroblastoma mouse model

Activating germline mutations of anaplastic lymphoma kinase (ALK) occur in most cases of hereditary neuroblastoma (NB) and the constitutively active kinase activity of ALK promotes cell proliferation and survival in NB. Therefore, ALK kinase is a potential therapeutic target for NB. In this study, we show that the novel ALK inhibitor alectinib effectively suppressed cell proliferation and induces apoptosis in NB cell lines with either wild-type ALK or mutated ALK (F1174L and D1091N) by blocking ALK-mediated PI3K/Akt/mTOR signaling. In addition, alectinib enhanced doxorubicin-induced cytotoxicity and apoptosis in NB cells. Furthermore, alectinib induced apoptosis in an orthotopic xenograft NB mouse model. Also, in the TH-MYCN transgenic mouse model, alectinib resulted in decreased tumor growth and prolonged survival time. These results indicate that alectinib may be a promising therapeutic agent for the treatment of NB.