Overexpression of PEAK1 contributes to epithelial-mesenchymal transition and tumor metastasis in lung cancer through modulating ERK1/2 and JAK2 signaling

Current understanding of PEAK family members in regulation of cellular signaling pathways and cancer therapy

Cancer evades therapy by multiple mechanisms, leading to uncontrolled cell growth and metastasis. Targeted therapies have shown promise in treating cancer by focusing on pathways within cancer cells. The PEAK family, comprising PEAK1 (SgK269), PEAK2 (SgK223/Pragmin), and the latest addition, PEAK3 (C19orf35), plays a crucial role in modulating cellular processes. Dysregulation and hyperactivity of these proteins, through overexpression or mutations, are associated with a wide range of cancers. This review delves into the different roles of the PEAK family members in regulating cell signaling pathways and highlights their potential in cancer therapy.

Black Phosphorus-Loaded Gelatin Methacryloyl Hydrogels Enhance Angiogenesis via Activation of the PEAK1-MAPK Pathway

Repair and regeneration of oral and maxillofacial tissue defects remain significant challenges, mainly due to the limitations of existing treatment approaches. Conventional methods such as transplantation, tissue scaffolds, growth factors, and stem cell therapies often face obstacles, including donor shortages, insufficient vascularization, and safety concerns. There is an urgent need for innovative therapeutic strategies to effectively promote vascular regeneration while minimizing complications. Black phosphorus nanosheets (BPNSs) and hydrogels present significant advantages and broad application potential as tissue regeneration carriers due to their biocompatibility, degradability, and controlled drug release properties. By combining various characterization techniques and detection methods, we conducted a thorough analysis of BPNSs and gelatin methacryloyl (GelMA) scaffolds loaded with BPNSs (BP-GelMA). The results indicate that this study successfully prepared BPNSs with uniform size, good dispersion, and intact structure. Moreover, the BP-GelMA composite demonstrated excellent swelling behavior and structural stability while effectively enabling the controlled release of BPNSs. This study investigated the angiogenic effects of BP-GelMA at concentrations of 0, 12.5, and 25.0 μg/mL. In vitro experiments showed that BP-GelMA significantly enhanced endothelial cell proliferation, migration, and tube formation. In vivo results demonstrated that 12.5 μg/mL and 25.0 μg/mL BP-GelMA did not induce significant developmental toxicity in zebrafish and effectively promoted neovascularization. RNA-Seq analysis revealed that BP-GelMA activates angiogenesis-related biological processes. Mechanistic studies identified PEAK1 as a central regulator, driving vascular formation through activation of the MAPK signaling pathway. These findings highlight the potential of BP-GelMA as a therapeutic strategy for promoting angiogenesis and underscore the importance of optimizing BP-GelMA concentrations to achieve maximum therapeutic efficacy and safety in clinical applications.

Activation of CAMK2 by pseudokinase PEAK1 represents a targetable pathway in triple negative breast cancer

The PEAK family of pseudokinases, comprising PEAK1-3, play oncogenic roles in several poor prognosis human cancers, including triple negative breast cancer (TNBC). However, therapeutic targeting of pseudokinases is challenging due to their lack of catalytic activity. To address this, we screen for PEAK1 effectors and identify calcium/calmodulin-dependent protein kinase 2 (CAMK2)D and CAMK2G. PEAK1 promotes CAMK2 activation in TNBC cells via PLCγ1/Ca2+ signalling and direct binding to CAMK2. In turn, CAMK2 phosphorylates PEAK1 to enhance association with PEAK2, which is critical for PEAK1 oncogenic signalling. To achieve pharmacologic targeting of PEAK1/CAMK2, we repurpose RA306, a second generation CAMK2 inhibitor. RA306 inhibits PEAK1-enhanced migration and invasion of TNBC cells in vitro and significantly attenuates TNBC xenograft growth and metastasis in a manner mirrored by PEAK1 ablation. Overall, these studies establish PEAK1 as a critical cell signalling nexus that integrates Ca2+ and tyrosine kinase signals and identify CAMK2 as a therapeutically 'actionable' target downstream of PEAK1.

Colorectal carcinoma progression is not influenced by the pseudokinase PEAK1

The scaffold protein PEAK1 acts downstream of integrin adhesion complexes and the epidermal growth factor receptor, orchestrating signaling events that control cell proliferation and cytoskeletal remodeling. In this study we investigated the role of PEAK1 in colorectal carcinoma (CRC) progression using various in vitro and in vivo models to replicate the stepwise pathogenesis of CRC. While we observed a cell-type specific role for PEAK1 in the proliferation and in human CRC cell lines in vitro, our in vivo experiments using different CRC mouse models driven by loss of Apc, with or without oncogenic Kras or Pten loss suggest that PEAK1 does not significantly contribute to tumor formation in vivo. However, the survival time of Peak1-/- mice in the Apcfl/+ model appeared to be slightly increased. Furthermore, PEAK1 promotes EGF-induced Caco-2 cell proliferation and regulates spheroid polarization and lumenization. Given that the Caco-2 cells harbor mutations in the tumor suppressors APC and β-CATENIN, but not in other tumor suppressors or in proto-oncogenes, we conclude that the PEAK1's impact on colon carcinogenesis is limited, potentially playing a role in the initial stage of the adenoma to carcinoma progression.

Lung cancer exosomal Gal3BP promotes osteoclastogenesis with potential connotation in osteolytic metastasis

New insights into cellular interactions and key biomolecules involved in lung cancer (LC) bone metastasis could offer remarkable therapeutic benefits. Using a panel of four LC cells, we investigated LC-bone interaction by exposing differentiating osteoclasts (OCs) to LC cells (LC-OC interaction) directly in a co-culture setting or indirectly via treatment with LC secretomes (conditioned media or exosomes). LC-OC interaction facilitated the production of large-sized OCs (nuclei > 10) coupled with extensive bone resorption pits. Proteomic analysis of LC exosomes identified galectin-3-binding protein (Gal3bp) as a potential biomarker which was released primarily by most of LC-derived exosomes. The facilitation of OC differentiation and function by LC-exosomal Gal3bp was supported by the application of recombinant Gal3bp and anti-Gal3bp in OC treatment. Further, our results exhibited a dysregulation of crucial OC markers (TRAF6, p-SAPK/JNK, p-44/42 MAPK, NFAT2 and CD9) during LC-OC interaction that possibly contributed to the facilitation of osteoclastogenesis. Simulation of bone metastasis via intratibial injection of LC cells revealed Gal3bp's possible roles in enhancing OC activation leading to osseous tissue resorption. Overall, this work implicated LC-exosomal Gal3bp in osteolytic metastasis of LC which warrants further studies to assess its potential prognostic and therapeutic relevance.

Targeting PEAK1 sensitizes anaplastic thyroid carcinoma cells harboring BRAFV600E to Vemurafenib by Bim upregulation

Pseudopodium-enriched atypical kinase 1 (PEAK1) has been demonstrated to be upregulated in human malignancies and cells. Enhanced PEAK1 expression facilitates tumor cell survival and chemoresistance. However, the role of PEAK1 inhibition to anaplastic thyroid carcinoma cell (ATC) and vemurafenib resistance is still unknown. Here, we observed that targeting PEAK1 inhibited cell viability and colony formation, but not cell apoptosis in both of the 8505C and Hth74 cells in vitro. Targeting PEAK1 sensitized 8505C and Hth74 cells to vemurafenib by inducing cell apoptosis, and thereby decreasing cell viability. Mechanistically, vemurafenib treatment upregulated PEAK1 expression. Combined PEAK1 depletion and Vemurafenib treatment upregulated Bim expression. Targeting PEAK1 sensitized vemurafenib-induced apoptosis by upregulating Bim. In conclusion, vemurafenib resistance in ATC cells harboring BRAFV600E is associated with PEAK1 activation, resulting in the inhibition of pro-apoptotic Bim protein. Therefore, targeting PEAK1 may be an effective strategy to sensitize ATC harboring BRAFV600E to vemurafenib.

The Role of Deubiquitinating Enzymes in Primary Bone Cancer

Bone is a living, intricate, and dynamic tissue providing locomotion and protection of the body. It also performs hematopoiesis and mineral homeostasis. Osteosarcoma (OS), Ewing sarcoma (ES), and chondrosarcoma (CS) are primary bone cancers. OS and ES mostly develop in younger individuals, and CS generally develops in adults. Ubiquitination regulates numerous cellular processes. The deubiquitinating enzymes (DUBs) detach the ubiquitin molecules from the ubiquitin labeled substrate, altering ubiquitinated protein functions and regulating protein stability via various signaling pathways. Protein homeostasis and bone remodeling are both crucially influenced by the UPS. Recently, there have been several reports on DUBs involved in bone homeostasis and various bone disorders through the regulation of osteoblasts and osteoclasts via NF-κB, Wnt/β-catenin, TRAF6, TGFβ, ERK1/2, and PI3K/Akt pathways. However, DUBs regulating function in bone homeostasis is still in its infancy. Here, we summarized several recent identifications on DUBs, with a focus on their role in bone cancer progression. Therefore, the study attempts to summarize association with the expression level of DUBs as key factors driving bone cancers and also provide new insights on DUBs as key pharmacologic targets for bone cancer therapeutics.

Role of microRNA-363 during tumor progression and invasion

Recent progresses in diagnostic and therapeutic methods have significantly improved prognosis in cancer patients. However, cancer is still considered as one of the main causes of human deaths in the world. Late diagnosis in advanced tumor stages can reduce the effectiveness of treatment methods and increase mortality rate of cancer patients. Therefore, investigating the molecular mechanisms of tumor progression can help to introduce the early diagnostic markers in these patients. MicroRNA (miRNAs) has an important role in regulation of pathophysiological cellular processes. Due to their high stability in body fluids, they are always used as the non-invasive markers in cancer patients. Since, miR-363 deregulation has been reported in a wide range of cancers, we discussed the role of miR-363 during tumor progression and metastasis. It has been reported that miR-363 has mainly a tumor suppressor function through the regulation of transcription factors, apoptosis, cell cycle, and structural proteins. MiR-363 also affected the tumor progression via regulation of various signaling pathways such as WNT, MAPK, TGF-β, NOTCH, and PI3K/AKT. Therefore, miR-363 can be introduced as a probable therapeutic target as well as a non-invasive diagnostic marker in cancer patients.

Based on systematic druggable genome-wide Mendelian randomization identifies therapeutic targets for diabetes

Purpose

Diabetes and its complications cause a heavy burden of disease worldwide. In recent years, Mendelian randomization (MR) has been widely used to discover the pathogenesis and epidemiology of diseases, as well as to discover new therapeutic targets. Therefore, based on systematic "druggable" genomics, we aim to identify new therapeutic targets for diabetes and analyze its pathophysiological mechanisms to promote its new therapeutic strategies.

Material and method

We used double sample MR to integrate the identified druggable genomics to evaluate the causal effect of quantitative trait loci (eQTLs) expressed by druggable genes in blood on type 1 and 2 diabetes (T1DM and T2DM). Repeat the study using different data sources on diabetes and its complications to verify the identified genes. Not only that, we also use Bayesian co-localization analysis to evaluate the posterior probabilities of different causal variations, shared causal variations, and co-localization probabilities to examine the possibility of genetic confounding. Finally, using diabetes markers with available genome-wide association studies data, we evaluated the causal relationship between established diabetes markers to explore possible mechanisms.

Result

Overall, a total of 4,477 unique druggable genes have been gathered. After filtering using methods such as Bonferroni significance (P<1.90e-05), the MR Steiger directionality test, Bayesian co-localization analysis, and validation with different datasets, Finally, 7 potential druggable genes that may affect the results of T1DM and 7 potential druggable genes that may affect the results of T2DM were identified. Reverse MR suggests that C4B may play a bidirectional role in the pathogenesis of T1DM, and none of the other 13 target genes have a reverse causal relationship. And the 7 target genes in T2DM may each affect the biomarkers of T2DM to mediate the pathogenesis of T2DM.

Conclusion

This study provides genetic evidence supporting the potential therapeutic benefits of targeting seven druggable genes, namely MAP3K13, KCNJ11, REG4, KIF11, CCNE2, PEAK1, and NRBP1, for T2DM treatment. Similarly, targeting seven druggable genes, namely ERBB3, C4B, CD69, PTPN22, IL27, ATP2A1, and LT-β, has The potential therapeutic benefits of T1DM treatment. This will provide new ideas for the treatment of diabetes and also help to determine the priority of drug development for diabetes.

Evaluation of SgK269 expression in colon cancer patients and the effects of hAMSCs secretome on tumor invasion through SgK269/c-Src/p-P130Cas/p-Paxillin/p-ERK1/2 signaling pathway in HT-29 colon cancer cells

Colon cancer is the fifth leading cause of cancer-related deaths worldwide. Stem cells have unique characteristics and are considered as a novel therapeutic platform for cancer. Sugen Kinase 269 (SgK269) is considered as an oncogenic scaffolding pseudo kinase which governs the rearranging of the cytoskeleton, cellular motility, and invasion. The aim of this study is to evaluate the expression of SgK269 in colon cancer patients and explore the therapeutic effects of human amniotic mesenchymal stromal cells (hAMSCs) on invasion and proliferation of colon cancer cells (HT-29) through analyzing SgK269/c-Src/p-P130Cas/p-Paxillin/p-ERK1/2 signaling pathway. In this regard, we collected 30 samples from colon cancer patients and evaluated SgK269 expression using quantitative real-time PCR (qRT-PCR). Next, we employed a co-culture system using Transwell 6-well plates and after 72 h, tumor growth promotion and invasion were analyzed in hAMSCs-treated HT-29 cells through SgK269/c-Src/p-P130Cas/p-Paxillin/p-ERK1/2/Rac signaling pathway using qRT-PCR, western blot method, MTT assay, wound healing assay, and DAPI staining. Our results showed upregulation of SgK269 in colon cancer patients. Treatment of HT-29 colon cancer cells with hAMSCs secretome can inhibit SgK269/c-Src/p-P130Cas/p-Paxillin/p-ERK1/2/Rac signaling pathway and the resulting suppression of cell invasion and proliferation. Our results suggest that SgK269 is an important target in colon cancer therapy and MSCs secretome may be an effective therapeutic approach to inhibit colon cancer cell invasion and proliferation through SgK269/c-Src/p-P130Cas/p-Paxillin/p-ERK1/2/Rac signaling pathway.

Structural mapping of PEAK pseudokinase interactions identifies 14-3-3 as a molecular switch for PEAK3 signaling

PEAK pseudokinases regulate cell migration, invasion and proliferation by recruiting key signaling proteins to the cytoskeleton. Despite lacking catalytic activity, alteration in their expression level is associated with several aggressive cancers. Here, we elucidate the molecular details of key PEAK signaling interactions with the adapter proteins CrkII and Grb2 and the scaffold protein 14-3-3. Our findings rationalize why the dimerization of PEAK proteins has a crucial function in signal transduction and provide biophysical and structural data to unravel binding specificity within the PEAK interactome. We identify a conserved high affinity 14-3-3 motif on PEAK3 and demonstrate its role as a molecular switch to regulate CrkII binding and signaling via Grb2. Together, our studies provide a detailed structural snapshot of PEAK interaction networks and further elucidate how PEAK proteins, especially PEAK3, act as dynamic scaffolds that exploit adapter proteins to control signal transduction in cell growth/motility and cancer.

Selection signatures for local and regional adaptation in Chinese Mongolian horse breeds reveal candidate genes for hoof health

BACKGROUND

Thousands of years of natural and artificial selection since the domestication of the horse has shaped the distinctive genomes of Chinese Mongolian horse populations. Consequently, genomic signatures of selection can provide insights into the human-mediated selection history of specific traits and evolutionary adaptation to diverse environments. Here, we used genome-wide SNPs from five distinct Chinese Mongolian horse populations to identify genomic regions under selection for the population-specific traits, gait, black coat colour, and hoof quality. Other global breeds were used to identify regional-specific signatures of selection.

RESULTS

We first identified the most significant selection peak for the Wushen horse in the region on ECA23 harbouring DMRT3, the major gene for gait. We detected selection signatures encompassing several genes in the Baicha Iron Hoof horse that represent good biological candidates for hoof health, including the CSPG4, PEAK1, EXPH5, WWP2 and HAS3 genes. In addition, an analysis of regional subgroups (Asian compared to European) identified a single locus on ECA3 containing the ZFPM1 gene that is a marker of selection for the major domestication event leading to the DOM2 horse clade.

CONCLUSIONS

Genomic variation at these loci in the Baicha Iron Hoof may be leveraged in other horse populations to identify animals with superior hoof health or those at risk of hoof-related pathologies. The overlap between the selection signature in Asian horses with the DOM2 selection peak raises questions about the nature of horse domestication events, which may have involved a prehistoric clade other than DOM2 that has not yet been identified.

Exosome-delivered circSATB2 targets the miR-330-5p/PEAK1 axis to regulate proliferation, migration and invasion of lung cancer cells

Exosomes can carry various kinds of RNAs to mediate intercellular communication. Circular RNA (circRNA) special AT-rich sequence-binding protein 2 (circSATB2) was identified as an oncogene in lung cancer. This study was performed to explore the association of circSATB2 with exosomes and the regulatory mechanism of circSATB2. Exosomes could transmit circSATB2 into lung cancer cells. Exosomes enhanced cell proliferation, invasion, and migration by carrying circSATB2. Exosomal circSATB2 abrogated the inhibitory effect of short hairpin (sh)-circSATB2 on lung cancer progression. Moreover, circSATB2 promoted tumor growth in vivo via exosomes. CircSATB2 interacted with microRNA-330-5p (miR-330-5p) and miR-330-5p targeted pseudopodium enriched atypical kinase 1 (PEAK1). In addition, circSATB2 affected the PEAK1 level via sponging miR-330-5p in lung cancer cells. All results suggested that exosomal transfer of circSATB2 contributed to the malignant development of lung cancer by acting as a sponge of miR-330-5p to upregulate PEAK1.

Oncogenic Signalling of PEAK2 Pseudokinase in Colon Cancer

Simple Summary

Catalytically inactive kinases, also named pseudokinases, play important roles in the regulation of cell growth and adhesion. While frequently deregulated in human cancer, their role in tumour development is partially elucidated. Here, we report an important tumour function for the pseudokinase PEAK2 in colorectal cancer (CRC) and propose that PEAK2 upregulation can affect cancer cell adhesive properties through an ABL-dependent mechanism to enable cancer progression. Therefore, targeting PEAK2 oncogenic activity with small tyrosine kinases (TK) inhibitors may be of therapeutic interest in colorectal cancer (CRC).

Abstract

The PEAK family pseudokinases are essential components of tyrosine kinase (TK) pathways that regulate cell growth and adhesion; however, their role in human cancer remains unclear. Here, we report an oncogenic activity of the pseudokinase PEAK2 in colorectal cancer (CRC). Notably, high PRAG1 expression, which encodes PEAK2, was associated with a bad prognosis in CRC patients. Functionally, PEAK2 depletion reduced CRC cell growth and invasion in vitro, while its overexpression increased these transforming effects. PEAK2 depletion also reduced CRC development in nude mice. Mechanistically, PEAK2 expression induced cellular protein tyrosine phosphorylation, despite its catalytic inactivity. Phosphoproteomic analysis identified regulators of cell adhesion and F-actin dynamics as PEAK2 targets. Additionally, PEAK2 was identified as a novel ABL TK activator. In line with this, PEAK2 expression localized at focal adhesions of CRC cells and induced ABL-dependent formation of actin-rich plasma membrane protrusions filopodia that function to drive cell invasion. Interestingly, all these PEAK2 transforming activities were regulated by its main phosphorylation site, Tyr413, which implicates the SRC oncogene. Thus, our results uncover a protumoural function of PEAK2 in CRC and suggest that its deregulation affects adhesive properties of CRC cells to enable cancer progression.

PEAK1 Y635 phosphorylation regulates cell migration through association with Tensin3 and integrins

Integrins mediate cell adhesion by connecting the extracellular matrix to the intracellular cytoskeleton and orchestrate signal transduction in response to chemical and mechanical stimuli by interacting with many cytoplasmic proteins. We used BioID to interrogate the interactomes of β1 and β3 integrins in epithelial cells and identified PEAK1 as an interactor of the RGD-binding integrins α5β1, αVβ3, and αVβ5 in focal adhesions. We demonstrate that the interaction between integrins and PEAK1 occurs indirectly through Tensin3, requiring both the membrane-proximal NPxY motif on the integrin β tail and binding of the SH2 domain of Tensin3 to phosphorylated Tyr-635 on PEAK1. Phosphorylation of Tyr-635 is mediated by Src and regulates cell migration. Additionally, we found that Shc1 localizes in focal adhesions in a PEAK1 phosphorylated Tyr-1188-dependent fashion. Besides binding Shc1, PEAK1 also associates with a protein cluster that mediates late EGFR/Shc1 signaling. We propose a model in which PEAK1 binds Tensin3 and Shc1 to converge integrin and growth factor receptor signal transduction.

Production and purification of the PEAK pseudokinases for structural and functional studies

The PEAK family of pseudokinases, which comprises PEAK1, PEAK2 and PEAK3, are newly identified scaffolds that dynamically assemble oncogenic signaling pathways known to contribute to the development of several aggressive cancers. A striking feature of this unique family of pseudokinase scaffolds is their large multi-domain structure, which allows them to achieve protein complex assemblies through their structural plasticity and functional versatility. Recent structural advances have begun to reveal the critical regulatory elements that control their function. Specifically, the dimer-dependent scaffolding activity of PEAK pseudokinases is emerging as a critical mechanism for their signaling function, in addition to their ability to hetero-associate to form higher-order regulatory networks to diversify and amplify their signaling output. Here, we present a suite of techniques that enable the efficient expression and purification of PEAK proteins for functional characterization.

Potential therapeutic effects of hAMSCs secretome on Panc1 pancreatic cancer cells through downregulation of SgK269, E-cadherin, vimentin, and snail expression

Pancreatic cancer is one of the leading causes of death from cancer worldwide. The current treatment options for pancreatic cancer are unsuccessful and thereby, finding novel and more effective therapeutic strategies is urgently required. Stem cells-based therapies are currently believed to be a potential promising option in cancer therapy. Herein, we are interested in evaluating the therapeutic effects of human amniotic mesenchymal stromal cells (hAMSCs) secretome on tumor growth suppression and EMT inhibition in Panc1 pancreatic cancer cells using 2D and 3D cell culture models. For this purpose, we employed a co-culture system using 6-well Transwell plates with a pore diameter of 0.4 μm. After 72 h treatment of Panc1 cancer cells with hAMSCs, the expression of c-Src, EGFR, SgK269, E-cadherin, Vimentin, Snail transcriptional factor, Bax, Bcl2, and caspase 3 was analyzed by quantitative real-time PCR (qRT-PCR) and Western blot methods. Our results showed significant reduction in tumor cell growth and motility through downregulation of c-Src, EGFR, SgK269, E-cadherin, Vimentin, and Snail transcriptional factor expression in Panc1 pancreatic cancer cells. The induction of cellular apoptosis was also found. Our finding supports the idea that the secretome from hAMSCS has therapeutic effects on cancer cells.

Distinct PEAK3 interactors and outputs expand the signaling potential of the PEAK pseudokinase family

The pseudokinase scaffolds PEAK1 and PEAK2 are implicated in cancer cell migration and metastasis. We characterized the regulation and role of the third family member PEAK3 in cell signaling. Similar to PEAK1 and PEAK2, PEAK3 formed both homotypic and heterotypic complexes. In addition, like PEAK1, it bound to the adaptors Grb2 and CrkII. However, unlike PEAK1 and PEAK2, homodimerized PEAK3 also interacted with the ARF GTPase-activating protein ASAP1, the E3 ubiquitin ligase Cbl, and the kinase PYK2. Dimerization and subsequent phosphorylation on Tyr²⁴, likely by a Src family kinase, were required for the binding of PEAK3 to Grb2 and ASAP1. Interactions with Grb2, CrkII, ASAP1, Cbl, and PYK2 exhibited contrasting dynamics upon cell stimulation with epidermal growth factor (EGF), in part due to PEAK3 dephosphorylation mediated by the phosphatase PTPN12. Overexpressing PEAK3 in mesenchymal-like MDA-MB-231 breast cancer cells enhanced cell elongation in a manner dependent on PEAK3 dimerization, and manipulation of PEAK3 expression demonstrated a positive role for this scaffold in regulating cell migration. Overexpressing PEAK3 in PEAK1/2 double-knockout MCF-10A breast epithelial cells enhanced acinar growth, impaired basement membrane integrity, and promoted invasion in three-dimensional cultures, with the latter two effects dependent on the binding of PEAK3 to Grb2 and ASAP1. PEAK1 and PEAK2 quantitatively and temporally influenced PEAK3 function. These findings characterize PEAK3 as an integral, signal-diversifying member of the PEAK family with scaffolding roles that promote cell proliferation, migration, and invasion.

SHED-Dependent Oncogenic Signaling of the PEAK3 Pseudo-Kinase

Simple Summary

The human kinome is composed of about 50 pseudo-kinases with unclear function, because they are predicted to be catalytically inactive; however, they are shown to play an important role in cancer, similar to active kinases. Understanding how these pseudo-kinases promote tumor formation despite their catalytic inactivity is a great challenge, which may lead to innovative anti-cancer therapies. The PEAK1 and 2 pseudo-kinases have emerged as important components of the protein tyrosine kinase pathway implicated in cancer progression. They can signal using a scaffolding mechanism via a conserved split helical dimerization (SHED) module. In this study, we uncovered a similar SHED-dependent oncogenic activity for PEAK3, a recently discovered new member of this family. We also show that this new signaling mechanism may be implicated in acute myeloid leukemia.

Abstract

The PEAK1 and Pragmin/PEAK2 pseudo-kinases have emerged as important components of the protein tyrosine kinase pathway implicated in cancer progression. They can signal using a scaffolding mechanism that involves a conserved split helical dimerization (SHED) module. We recently identified PEAK3 as a novel member of this family based on structural homology; however, its signaling mechanism remains unclear. In this study, we found that, although it can self-associate, PEAK3 shows higher evolutionary divergence than PEAK1/2. Moreover, the PEAK3 protein is strongly expressed in human hematopoietic cells and is upregulated in acute myeloid leukemia. Functionally, PEAK3 overexpression in U2OS sarcoma cells enhanced their growth and migratory properties, while its silencing in THP1 leukemic cells reduced these effects. Importantly, an intact SHED module was required for these PEAK3 oncogenic activities. Mechanistically, through a phosphokinase survey, we identified PEAK3 as a novel inducer of AKT signaling, independent of growth-factor stimulation. Then, proteomic analyses revealed that PEAK3 interacts with the signaling proteins GRB2 and ASAP1/2 and the protein kinase PYK2, and that these interactions require the SHED domain. Moreover, PEAK3 activated PYK2, which promoted PEAK3 tyrosine phosphorylation, its association with GRB2 and ASAP1, and AKT signaling. Thus, the PEAK1-3 pseudo-kinases may use a conserved SHED-dependent mechanism to activate specific signaling proteins to promote oncogenesis.

MiR-552-3p facilitated cell proliferation, migration and invasion by sponging Fibulin 5 in non-small cell lung cancer via activation of ERK/GSK3β/β-catenin signaling pathway

Apart from the fact that miR-552-3p is known to promote cell progression among various cancers, its function on non-small cell lung cancer (NSCLC) is unknown which therefore emerges as the purpose of this research. TargetScan, Starbase, miRWalk, miRDB and the Cancer Genome Atlas Lung Adenocarcinoma (TCGA-LUAD) were utilized to analyze the target genes of miR-552-3p. NSCLC cells were transfected with miR-552-3p mimic, miR-552-3p inhibitor, Fibulin 5 (FBLN5) overexpression plasmid, and small interfering FBLN5 (siFBLN5) and treated with extracellular regulated protein kinases (ERK) pathway inhibitor PD98059. MiR-552-3p, FBLN5, p-ERK, ERK, p-glycogen synthase kinase 3β (GSK3β) and β-catenin levels were detected through quantitative reverse transcription-polymerase chain reaction and western blot. The binding sites between miR-552-3p and FBLN5 were predicted by TargetScan, which was tested through dual luciferase reporter analysis. Cell viability, migration and invasion were determined by cell counting kit-8 (CCK-8) assay, wound healing assay and transwell assay, respectively. MiR-552-3p expression was upregulated in NSCLC and FBLN5 functioned as its target. MiR-552-3p mimic promoted proliferation, migration, invasion, p-ERK, p-GSK3β and β-catenin expressions in NSCLC cells while miR-552-3p inhibitor did the opposite. Overexpressed FBLN5 suppressed proliferation, migration, invasion, p-ERK, p-GSK3β and β-catenin expressions in NSCLC cells whereas siFBLN5 exerted the effects opposite to overexpressed FBLN5. PD98059 enhanced the effect of overexpressed FBLN5 on NSCLC cell migration and invasion while reversing the effect of siFBLN5. MiR-552-3p facilitated cell proliferation, migration and invasion in NSCLC through sponging FBLN5 via activation of ERK/GSK3β/β-catenin pathway.

PEAK1 promotes invasion and metastasis and confers drug resistance in breast cancer

Pseudopodium-enriched atypical kinase 1 (PEAK1) has been reported to be upregulated in human malignancies and is correlated with a poor prognosis. Enhanced PEAK1 expression facilitates tumor cell survival, invasion, metastasis and chemoresistance. However, the role of PEAK1 in breast cancer is unclear. We investigated PEAK1 expression in breast cancer and analyzed the relationship with clinicopathological status and chemotherapy resistance. We also investigated the role of PEAK1 in breast cancer cells in vitro and in vivo. Immunohistochemistry for PEAK1 was performed in 112 surgically resected breast cancer tissues. The association between clinicopathological status, chemotherapy resistance and PEAK1 expression was determined. The effect of PEAK1 overexpression or downregulation on proliferation, colony formation, invasion, migration, metastasis and doxorubicin sensitivity in MCF-7 cells in vitro and in vivo was studied. PEAK1 was overexpressed in breast cancer tissues. High PEAK1 expression was correlated with tumor size, high tumor grade, tumor stage, lymph node metastasis, recurrence, Ki-67 expression, Her-2 expression and chemotherapy resistance. Inhibiting PEAK1 decreased cell growth, invasion, metastasis and reversed chemoresistance to doxorubicin in breast cancer cells both in vitro and in vivo. High PEAK1 expression was associated with the invasion, metastasis and chemoresistance of breast cancers. Furthermore, targeting PEAK1 inhibited cell growth and metastasis and reversed chemoresistance in breast cancer cells. Targeting PEAK1 could be an effective treatment strategy for breast cancer.

Importance of Circ0009910 in colorectal cancer pathogenesis as a possible regulator of miR-145 and PEAK1

Introduction

Colorectal cancer (CRC) is one of the most frequent neoplasms in the world. Based on the emerging role of noncoding RNAs, particularly circular RNAs in pathogenesis of cancers, we designed this study to inspect the expression levels of a circ0009910-mediated regulatory pathway in colorectal cancer.

Methods

After bioinformatics analyses and construction of putative circ0009910/ miR-145-5p/PEAK1 pathway, the expression levels of these components were evaluated in 50 CRC tissues and adjacent specimens by quantitative real-time PCR. Moreover, we appraised the correlation coefficients between these transcripts and calculated the correlation between circ0009910 expression levels with clinicopathological features of patients.

Results

Circ0009910 and PEAK1 were significantly upregulated, while miR-145-5p was decreased in CRC samples compared with adjacent tissues (p < 0.05). Moreover, statistically significant correlations were observed between expression levels of circ0009910, miR-145-5p, and PEAK1. We also reported considerable correlations between circ0009910 expression and clinicopathological parameters including sex and perineural invasion. Finally, ROC curve analysis showed circ0009910 level as a discriminative biomarker for CRC.

Conclusion

For the first time, we could introduce circ0009910 as an important biomarker in CRC. Collectively, this investigation helped us to identify a newly diagnosed pathway in CRC that can be a potential axis for designing effective drugs for treatment of CRC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02378-0.

Serum Proteomic Analysis of Cannabis Use Disorder in Male Patients

Cannabis use has been growing recently and it is legally consumed in many countries. Cannabis has a variety of phytochemicals including cannabinoids, which might impair the peripheral systems responses affecting inflammatory and immunological pathways. However, the exact signaling pathways that induce these effects need further understanding. The objective of this study is to investigate the serum proteomic profiling in patients diagnosed with cannabis use disorder (CUD) as compared with healthy control subjects. The novelty of our study is to highlight the differentially changes proteins in the serum of CUD patients. Certain proteins can be targeted in the future to attenuate the toxicological effects of cannabis. Blood samples were collected from 20 male individuals: 10 healthy controls and 10 CUD patients. An untargeted proteomic technique employing two-dimensional difference in gel electrophoresis coupled with mass spectrometry was employed in this study to assess the differentially expressed proteins. The proteomic analysis identified a total of 121 proteins that showed significant changes in protein expression between CUD patients (experimental group) and healthy individuals (control group). For instance, the serum expression of inactive tyrosine protein kinase PEAK1 and tumor necrosis factor alpha-induced protein 3 were increased in CUD group. In contrast, the serum expression of transthyretin and serotransferrin were reduced in CUD group. Among these proteins, 55 proteins were significantly upregulated and 66 proteins significantly downregulated in CUD patients as compared with healthy control group. Ingenuity pathway analysis (IPA) found that these differentially expressed proteins are linked to p38MAPK, interleukin 12 complex, nuclear factor-κB, and other signaling pathways. Our work indicates that the differentially expressed serum proteins between CUD and control groups are correlated to liver X receptor/retinoid X receptor (RXR), farnesoid X receptor/RXR activation, and acute phase response signaling.

Pseudopodium enriched atypical kinase 1(PEAK1) promotes invasion and of melanoma cells by activating JAK/STAT3 signals

Pseudopodium enriched atypical kinase 1(PEAK1) is a non-receptor tyrosine kinase, which is enriched in the pseudopodia of migrating cells and plays an important role in regulating cell migration and proliferation. In the study, we investigate the therapeutic effect of PEAK1 on melanoma cells in vitro and in vivo. We used a lentiviral vector to express short hairpin RNAs (Lv-PEAK1 shRNA) for inhibiting PEAK1 expression in the melanoma SKMEL28 cells. A full-length PEAK1 gene was cloned into the pcDNA 3.1 (+) plasmid and used to infect the melanoma SKMEL19 cells. P6 (also known as Pyridines 6, EMD Chemicals), the Pan-JAK inhibitor, was used to inhibit the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) pathway. The cell counting kit-8 (CCK-8), colony formation assay and transwell assay were used to detect cell proliferation, growth and invasion in vitro. The effect of PEAK1 on melanoma progression in vivo was also evaluated. Protein expression of PEAK1, E-cadherin, vimentin and JAK/STAT3 was measured using western blot assay or immunohistochemistry. The results showed that enforced PEAK1 expression facilitated melanoma cell growth, invasion and metastasis via activating JAK/STAT3 signals, and PEAK1 knockdown inhibited melanoma cell growth, invasion and metastasis via inactivating JAK/STAT3 signals. Further work demonstrated that P6 (500 nM) treatment reversed PEAK1-induced effect in melanoma cells. PEAK1 promotes tumorigenesis and metastasis via activating JAK/STAT3 signals, and PEAK1 knockdown reduced tumorigenesis and metastasis in melanoma via inactivating JAK/STAT3 signals, providing a novel therapeutic strategy for melanoma treatment.

A SNAI2-PEAK1-INHBA stromal axis drives progression and lapatinib resistance in HER2-positive breast cancer by supporting subpopulations of tumor cells positive for antiapoptotic and stress signaling markers

Intercellular mechanisms by which the stromal microenvironment contributes to solid tumor progression and targeted therapy resistance remain poorly understood, presenting significant clinical hurdles. PEAK1 (Pseudopodium-Enriched Atypical Kinase One) is an actin cytoskeleton- and focal adhesion-associated pseudokinase that promotes cell state plasticity and cancer metastasis by mediating growth factor-integrin signaling crosstalk. Here, we determined that stromal PEAK1 expression predicts poor outcomes in HER2-positive breast cancers high in SNAI2 expression and enriched for MSC content. Specifically, we identified that the fibroblastic stroma in HER2-positive breast cancer patient tissue stains positive for both nuclear SNAI2 and cytoplasmic PEAK1. Furthermore, mesenchymal stem cells (MSCs) and cancer-associated fibroblasts (CAFs) express high PEAK1 protein levels and potentiate tumorigenesis, lapatinib resistance and metastasis of HER2-positive breast cancer cells in a PEAK1-dependent manner. Analysis of PEAK1-dependent secreted factors from MSCs revealed INHBA/activin-A as a necessary factor in the conditioned media of PEAK1-expressing MSCs that promotes lapatinib resistance. Single-cell CycIF analysis of MSC-breast cancer cell co-cultures identified enrichment of p-Akthigh/p-gH2AXlow, MCL1high/p-gH2AXlow and GRP78high/VIMhigh breast cancer cell subpopulations by the presence of PEAK1-expressing MSCs and lapatinib treatment. Bioinformatic analyses on a PEAK1-centric stroma-tumor cell gene set and follow-up immunostaining of co-cultures predict targeting antiapoptotic and stress pathways as a means to improve targeted therapy responses and patient outcomes in HER2-positive breast cancer and other stroma-rich malignancies. These data provide the first evidence that PEAK1 promotes tumorigenic phenotypes through a previously unrecognized SNAI2-PEAK1-INHBA stromal cell axis.

Expression and functional characterization of INPP4B in gallbladder cancer patients and gallbladder cancer cells

Background

Inositol polyphosphate 4-phosphatase type II (INPP4B) is a negative regulator of the PI3K-Akt signalling pathway and plays a contradictory role in different types of cancers. However, the its biological role played by INPP4B in human gallbladder cancer (GBC) has not been elucidated. In this study, we investigated the expression, clinical significance and biological function of INPP4B in GBC patients and cell lines.

Methods

The INPP4B protein expression levels in gallbladder cancer tissues and normal gallbladder tissues were detected by immunohistochemistry, and the clinical significance of INPP4B was analysed. Knockdown and overexpression of INPP4B in GBC-SD and SGC-996 cells followed by cell proliferation, clonogenic, apoptosis detection, scratch wound-healing and transwell assays were used to identify INPP4B function in vitro.

Results

INPP4B was up-regulated in human GBC tissues compared with normal gallbladder tissues and was related to histopathological differentiation (p = 0.026). Here, we observed that INPP4B was highly expressed in high-moderately differentiated tumours compared with low-undifferentiated tumours (p = 0.022). Additionally, we found that INPP4B expression was not associated with overall survival of GBC patients (p = 0.071) and was not an independent prognostic factor. Furthermore, when we stratified the relationship between INPP4B expression and the prognosis of GBC based on histopathological differentiation, we found that INPP4B played a contradictory role in GBC progression depending on the degree of differentiation. In addition, INPP4B knockdown inhibited the proliferation, colony formation, migration and invasion in GBC cells, while INPP4B overexpression had the opposite effects in vitro, which indicates its role as an oncoprotein.

Conclusions

These findings suggested that INPP4B may play a dual role in the prognosis of GBC depending on the degree of differentiation and that INPP4B might act as an oncogene in gallbladder cancer cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08143-6.

LncRNA NORAD, sponging miR-363-3p, promotes invasion and EMT by upregulating PEAK1 and activating the ERK signaling pathway in NSCLC cells

Lung cancer is one of the most common malignant tumors in the world. Non-small cell lung cancer (NSCLC) accounts for about 80% of all lung cancers. About 75% of patients are in the middle and advanced stages at the time of discovery, and the 5-year survival rate is very low. The aim of this study was to investigate the role of long non-coding RNA (lncRNA) NORAD in the pathogenesis of NSCLC. We found that lncRNA NORAD was highly expressed in human NSCLC tissues and cell lines. The CCK-8 assay results showed that lncRNA NORAD had no effect on cell proliferation. The Transwell assay and Western blotting results showed that overexpression of lncRNA NORAD promoted the invasion and epithelial-mesenchymal transition (EMT) of NSCLC cells. Then bioinformatics analysis was used to screen for candidate miRNA bound with lncRNA NORAD and the target gene of miRNA in NSCLC. The luciferase reporter gene assay and RNA pull-down assay were used to verify the relationship. We found that miR-363-3p expression was down-regulated, whereas PEAK1 expression was upregulated in NSCLC cells. We performed gain and loss function test of lncRNA NORAD, miR-363-3p and PEAK1, the results showed that while miR-363-3p-mimic inhibited cell invasion and EMT by targeting PEAK1, lncRNA NORAD acted as a sponge of miR-363-3p and promoted cell invasion and EMT by increasing the expression of PEAK1. In addition, p-ERK expression was detected by Western blotting to observe the effects of lncRNA NORAD, miR-363-3p and PEAK1 on activation of the ERK signaling pathway. Taken together, lncRNA NORAD upregulated the expression of PEAK1 through sponging miR-363-3p, and then activated the ERK signaling pathway, thereby promoting the development of NSCLC.

Integrated Genomic and Transcriptomic Analysis reveals key genes for predicting dual-phenotype Hepatocellular Carcinoma Prognosis

Dual-phenotype hepatocellular carcinoma (DPHCC) expresses both hepatocyte and cholangiocyte markers, and is characterized by high recurrence and low survival rates. The underlying molecular mechanisms of DPHCC pathogenesis are unclear.

We performed whole exome sequencing and RNA sequencing of three subtypes of HCC (10 DPHCC, 10 CK19-positive HCC, and 14 CK19-negative HCC), followed by integrated bioinformatics analysis, including somatic mutation analysis, mutation signal analysis, differential gene expression analysis, and pathway enrichment analysis. Cox proportional hazard regression analyses were applied for exploring survival related characteristics.

We found that mutated genes in DPHCC patients were associated with carcinogenesis and immunity, and the up-regulated genes were mainly enriched in transcription-related and cancer-related pathways, and the down-regulated genes were mainly enriched in immune-related pathways. CXCL9 was selected as the hub gene, which is associated with immune cells and survival prognosis. Our results showed that low CXCL9 expression was significantly associated with poor prognosis, and its expression was significantly reduced in DPHCC samples.

In conclusion, we explored the molecular mechanisms governing DPHCC development and progression and identified CXCL9, which influences the immune microenvironment and prognosis of DPHCC and might be new clinically significant biomarkers for predicting prognosis.

Clinical significance of eukaryotic translation initiation factor 5A2 in papillary thyroid cancer

Eukaryotic translation initiation factor 5A2 (eIF5A2) plays an important role in tumor progression and prognosis evaluation. However, the potential role of eIF5A2 in human papillary thyroid cancer (PTC) is unknown. In this study, we aim to investigate the association between eIF5A2 expression and PTC clinical outcomes and underlying its Biological function in PTC cells in vitro and in vivo. The expression of eIF5A2 was examined by immunohistochemistry in PTC tissues and its adjacent tissue (n = 39) from 207 PTC patients. Functional analysis of eIF5A2 was performed in PTC cell lines in vitro and in vivo. The results showed that eIF5A2 was overexpressed in PTC tissues compared with the adjacent tissues. Enhanced eIF5A2 expression was significantly correlated with extrathyroidal extension (p = 0.012), lymph node metastasis (p = 0.002), TNM stage (p = 0.006), T classification (p = 0.047) and BRAF V600E mutation (p = 0.036). EIF5A2 inhibition prevented PTC cell growth, invasiveness and migration and induced cell apoptosis in vitro. Furthermore, eIF5A2 depletion inhibited tumor growth and metastasis in vivo. The data indicated that eIF5A2 could be employed as a novel prognostic marker and effective therapeutic target for PTC.

Mutation profiling in eight cases of vagal paragangliomas

Background

Vagal paragangliomas (VPGLs) belong to a group of rare head and neck neuroendocrine tumors. VPGLs arise from the vagus nerve and are less common than carotid paragangliomas. Both diagnostics and therapy of the tumors raise significant challenges. Besides, the genetic and molecular mechanisms behind VPGL pathogenesis are poorly understood.

Methods

The collection of VPGLs obtained from 8 patients of Russian population was used in the study. Exome library preparation and high-throughput sequencing of VPGLs were performed using an Illumina technology.

Results

Based on exome analysis, we identified pathogenic/likely pathogenic variants of the SDHx genes, frequently mutated in paragangliomas/pheochromocytomas. SDHB variants were found in three patients, whereas SDHD was mutated in two cases. Moreover, likely pathogenic missense variants were also detected in SDHAF3 and SDHAF4 genes encoding for assembly factors for the succinate dehydrogenase (SDH) complex. In a patient, we found a novel variant of the IDH2 gene that was predicted as pathogenic by a series of algorithms used (such as SIFT, PolyPhen2, FATHMM, MutationTaster, and LRT). Additionally, pathogenic/likely pathogenic variants were determined for several genes, including novel genes and some genes previously reported as associated with different types of tumors.

Conclusions

Results indicate a high heterogeneity among VPGLs, however, it seems that driver events in most cases are associated with mutations in the SDHx genes and SDH assembly factor-coding genes that lead to disruptions in the SDH complex.

INPP4B exerts a dual function in the stemness of colorectal cancer stem-like cells through regulating Sox2 and Nanog expression

Inositol polyphosphate 4-phosphatase type II (INPP4B), a lipid phosphatase, was identified as a negative regulator of phosphatidylinositol 3-kinase (PI3K)/Akt signaling in several cancers. The expression and biological function of INPP4B in human colorectal cancer (CRC) are controversial, while the role and molecular mechanism of INPP4B in colorectal cancer stem-like cells (CR-CSLCs) remains unclear. Here, we observed that INPP4B expression was markedly decreased in primary non-metastatic CR-CSLCs and increased in highly metastatic CR-CSLCs compared with corresponding control non-CSLCs. INPP4B overexpression inhibited self-renewal, and chemoresistance of primary non-metastatic CR-CSLCs, but exerted the opposite roles in highly metastatic CR-CSLCs in vitro. Similarly, INPP4B knockdown had dual functions in the self-renewal and chemoresistance of different CR-CSLCs. In addition, we demonstrated that INPP4B overexpression suppressed the tumorigenicity of primary non-metastatic CR-CSLCs while induced the tumorigenicity of highly metastatic CR-CSLCs in nude mice. Furthermore, INPP4B was found to modulate the stemness of CR-CSLCs by regulating Sox2 and Nanog expression, which was dependent on PI3K/PTEN/Akt signaling. In conclusion, our results highlight an important role of INPP4B in the stemness of CR-CSLCs for the first time and emphasize INPP4B as a dual therapeutic target for suppressing primary cancer cell proliferation and for preventing metastasis in CRC patients.

MDA-9/Syntenin (SDCBP): Novel gene and therapeutic target for cancer metastasis

The primary cause of cancer-related death from solid tumors is metastasis. While unraveling the mechanisms of this complicated process continues, our ability to effectively target and treat it to decrease patient morbidity and mortality remains disappointing. Early detection of metastatic lesions and approaches to treat metastases (both pharmacological and genetic) are of prime importance to obstruct this process clinically. Metastasis is complex involving both genetic and epigenetic changes in the constantly evolving tumor cell. Moreover, many discrete steps have been identified in metastatic spread, including invasion, intravasation, angiogenesis, attachment at a distant site (secondary seeding), extravasation and micrometastasis and tumor dormancy development. Here, we provide an overview of the metastatic process and highlight a unique pro-metastatic gene, melanoma differentiation associated gene-9/Syntenin (MDA-9/Syntenin) also called syndecan binding protein (SDCBP), which is a major contributor to the majority of independent metastatic events. MDA-9 expression is elevated in a wide range of carcinomas and other cancers, including melanoma, glioblastoma multiforme and neuroblastoma, suggesting that it may provide an appropriate target to intervene in metastasis. Pre-clinical studies confirm that inhibiting MDA-9 either genetically or pharmacologically profoundly suppresses metastasis. An additional benefit to blocking MDA-9 in metastatic cells is sensitization of these cells to a second therapeutic agent, which converts anti-invasion effects to tumor cytocidal effects. Continued mechanistic and therapeutic insights hold promise to advance development of truly effective therapies for metastasis in the future.

Antiproliferative and Antimetastatic Effects of Praeruptorin C on Human Non-Small Cell Lung Cancer Through Inactivating ERK/CTSD Signalling Pathways

Praeruptorin C (PC) reportedly has beneficial effects in terms of antiinflammation, antihypertension, and antiplatelet aggregation, and it potentially has anticancer activity. However, the effect of PC on human non-small cell lung cancer (NSCLC) is largely unknown. Compared with the effects of praeruptorin A and praeruptorin B, we observed that PC significantly suppressed cell proliferation, colony formation, wound closure, and migration and invasion of NSCLC cells. It induced cell cycle arrest in the G0/G1 phase, downregulated cyclin D1 protein, and upregulated p21 protein. PC also significantly reduced the expression of cathepsin D (CTSD). In addition, the phosphorylation/activation of the ERK1/2 signalling pathway was significantly suppressed in PC-treated NSCLC cells. Cotreatment with PC and U0126 synergistically inhibited CTSD expression, cell migration, and cell invasion, which suggests that the ERK1/2 signalling pathway is involved in the downregulation of CTSD expression and invasion activity of NSCLC cells by PC. These findings are the first to demonstrate the inhibitory effects of PC in NSCLC progression. Therefore, PC may represent a novel strategy for treating NSCLC.

Circ-PGAM1 promotes malignant progression of epithelial ovarian cancer through regulation of the miR-542-3p/CDC5L/PEAK1 pathway

Background

Epithelial ovarian cancer (EOC) is the most common ovarian malignant cancer. Circular RNA is a type of endogenous noncoding RNA and is considered as a novel regulatory molecule in the development and progression of tumors. This study investigated the expression and functions of a circular RNA, circular‐phosphoglycerate mutase 1 (circ‐PGAM1), in EOC tissues and cells.

Methods

The expression of circ‐PGAM1 and miR‐542‐3p in EOC was analyzed using quantitative RT‐PCR. Immunohistochemistry and western blot were performed to confirm the localization and expression of cell division cycle 5‐like (CDC5L) and pseudopodium enriched atypical kinase 1 (PEAK1) in EOC tissues. Cell lines (CAOV3 and OVCAR3) overexpressing or silencingcirc‐PGAM1 and miR‐542‐3p were established to explore the functions of circ‐PGAM1 and miR‐542‐3p in ovarian cancer cells. Furthermore, dual‐luciferase reporter assay was performed to study the interactions between circ‐PGAM1 and miR‐542‐3p and between miR‐542‐3p and CDC5L. CCK‐8, transwell, and flow cytometry were used to study the effect of circ‐PGAM1 and miR‐542‐3p on cell biological behaviors including proliferation, migration, invasion, and apoptosis. The interaction between CDC5L and the PEAK1 gene promoter was confirmed using chromatin immunoprecipitation (ChIP).

Results

Circ‐PGAM1 was upregulated in EOC tissues, whereas linear PGAM1 was not deregulated in EOC tissues. Silencing of circ‐PAGM1 inhibited proliferation, migration, and invasion of ovarian cancer cells and promoted cell apoptosis. MiR‐542‐3p was downregulated in EOC tissues, and miR‐542‐3p overexpression inhibited malignant progression of ovarian cancer cells. Circ‐PGAM1 directly interacted with miR‐542‐3p, with mutual negative feedback between them. CDC5L was a direct target of miR‐542‐3p and played an oncogenic role in ovarian cancer cells. Furthermore, the CDC5L protein binds directly to the PEAK1 promoter to promote its transcription. PEAK1 overexpression activated ERK1/2 and JAK2 signaling pathways and promoted malignant biological behaviors of ovarian cancer cells. Circ‐PAGM1 silencing combined with miR‐542‐3p overexpression played the greatest anticancer role in vivo.

Conclusion

The circ‐PGAM1/miR‐542‐3p/CDC5L/PEAK1 pathway played an important role in the progression of ovarian cancer and might be a novel therapeutic target for ovarian cancer.

Phospho-PTM proteomic discovery of novel EPO- modulated kinases and phosphatases, including PTPN18 as a positive regulator of EPOR/JAK2 Signaling

The formation of erythroid progenitor cells depends sharply upon erythropoietin (EPO), its cell surface receptor (erythropoietin receptor, EPOR), and Janus kinase 2 (JAK2). Clinically, recombinant human EPO (rhEPO) additionally is an important anti-anemia agent for chronic kidney disease (CKD), myelodysplastic syndrome (MDS) and chemotherapy, but induces hypertension, and can exert certain pro-tumorigenic effects. Cellular signals transduced by EPOR/JAK2 complexes, and the nature of EPO-modulated signal transduction factors, therefore are of significant interest. By employing phospho-tyrosine post-translational modification (p-Y PTM) proteomics and human EPO- dependent UT7epo cells, we have identified 22 novel kinases and phosphatases as novel EPO targets, together with their specific sites of p-Y modification. New kinases modified due to EPO include membrane palmitoylated protein 1 (MPP1) and guanylate kinase 1 (GUK1) guanylate kinases, together with the cytoskeleton remodeling kinases, pseudopodium enriched atypical kinase 1 (PEAK1) and AP2 associated kinase 1 (AAK1). Novel EPO- modified phosphatases include protein tyrosine phosphatase receptor type A (PTPRA), phosphohistidine phosphatase 1 (PHPT1), tensin 2 (TENC1), ubiquitin associated and SH3 domain containing B (UBASH3B) and protein tyrosine phosphatase non-receptor type 18 (PTPN18). Based on PTPN18's high expression in hematopoietic progenitors, its novel connection to JAK kinase signaling, and a unique EPO- regulated PTPN18-pY389 motif which is modulated by JAK2 inhibitors, PTPN18's actions in UT7epo cells were investigated. Upon ectopic expression, wt-PTPN18 promoted EPO dose-dependent cell proliferation, and survival. Mechanistically, PTPN18 sustained the EPO- induced activation of not only mitogen-activated protein kinases 1 and 3 (ERK1/2), AKT serine/threonine kinase 1-3 (AKT), and signal transducer and activator of transcription 5A and 5B (STAT5), but also JAK2. Each effect further proved to depend upon PTPN18's EPO- modulated (p)Y389 site. In analyses of the EPOR and the associated adaptor protein RHEX (regulator of hemoglobinization and erythroid cell expansion), wt-PTPN18 increased high molecular weight EPOR forms, while sharply inhibiting the EPO-induced phosphorylation of RHEX-pY141. Each effect likewise depended upon PTPN18-Y389. PTPN18 thus promotes signals for EPO-dependent hematopoietic cell growth, and may represent a new druggable target for myeloproliferative neoplasms.

The PEAK family of pseudokinases, their role in cell signalling and cancer

The study of pseudokinases has uncovered that catalysis-independent functions play a critical role in cell signalling regulation. However, how pseudokinases dynamically assemble and regulate oncogenic signalling pathways remains, in most cases, unclear due to a limited knowledge of the structural determinants that are critical for their functions. Here, we review the recent progress made to unravel the role of the PEAK family of pseudokinases, which comprises SgK269, SgK223 and the recently identified PEAK3, in assembling specific oncogenic signalling pathways that contribute to the progression of several aggressive cancers. We focus on recent structural advances revealing that SgK269 and SgK223 can homo- and heteroassociate via a unique dimerisation domain, comprising conserved regulatory helices directly surrounding the pseudokinase domain, which is also conserved in PEAK3. We also highlight a potential oligomerisation mechanism driven by the pseudokinase domain. While it is likely that homo- or heterodimerisation and oligomerisation mechanisms contribute to the assembly of complex signalling hubs and provide a means to spatially and temporally modulate and diversify signalling outputs, the exact role that these oncogenic scaffolds play in regulating cell migration, invasion and morphology remains unclear. Here, we attempt to link their structural characteristics to their cellular functions by providing a thorough analysis of the signalling transduction pathways they are known to modulate.

Downregulation of NSD3 (WHSC1L1) inhibits cell proliferation and migration via ERK1/2 deactivation and decreasing CAPG expression in colorectal cancer cells

Purpose: NSD3 (WHSC1L1) is a protein lysine methyltransferase that is recurrently amplified (8p11.23) in several cancer types, and its upregulation is involved in tumor cell proliferation, metastasis, and epithelial-mesenchymal transition (EMT). We aimed to evaluate its potential function as an oncogenic force in colorectal cancer (CRC), and to elucidate relevant mechanisms of its oncogenic activity. Materials and methods: NSD3 levels were analyzed in human CRC and adjacent normal tissues or cells by Western blot analysis and RT-qPCR. Expression levels of the proteins were detected by Western blot analysis and RT-qPCR. Results: NSD3 was significantly upregulated in both CRC tissues and cell lines. Knockdown of NSD3 expression resulted in significant decreases in CRC cell proliferation, migration, and EMT process marker proteins vimentin, simultaneously reducing E-cadherin and N-cadherin expression. The opposite results were observed when NSD3 was overexpressed. Additionally, overexpressing of NSD3 dramatically activated the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway and enhanced actin-capping protein (CAPG) expression. Furthermore, the proliferation and migration abilities evidently facilitated by pcDNA3.1(+) expression vector containing full-length CDS of NSD3 (pcDNA3.1(+)-NSD3, or NSD3) were partially decreased after incubation with ERK1/2 signaling pathway inhibitor (PD98059) and/or specific siRNA against CAPG (siCAPG) in SW480 and HT-29 CRC cells. Conclusion: NSD3 overexpression stimulated CRC cell proliferation and migration through targeting the ERK1/2 signaling pathway and downstream CAPG. Thus, NSD3 could serve as a promising target for anticancer drug development for patients with CRC.

INPP4B inhibits cell proliferation, invasion and chemoresistance in human hepatocellular carcinoma

Background: Inositol polyphosphate 4-phosphatase type II (INPP4B) has been identified as a negative regulator of phosphatidyl inositol 3-kinase (PI3K)/Akt signaling in human several cancers. However, the expression, clinical significance and biological function of INPP4B in human hepatocellular carcinoma (HCC) clinical tissues and cell lines are little known.

Materials and methods: We evaluated the expression of INPP4B in 86 cases of paired human HCC samples by immunohistochemistry, and the clinical significance of INPP4B expression was analyzed. The expression of INPP4B in five HCC cell lines was detected through using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot analyses. The role of INPP4B gene on HCC cell proliferation, apoptosis, migration, invasion as well as epithelial-to-mesenchymal transition (EMT) and chemoresistance was examined via INPP4B mammalian expression vector and small interfering RNA (siRNA) transfection in vitro. Western blot analysis was used to explore the downstream molecules modulated by INPP4B.

Results: Immunohistochemistry analysis revealed that INPP4B was significantly downregulated in HCC tissues compared with the corresponding normal tissues. The rate of INPP4B-positive staining was markedly lower in metastatic samples than in those of non-metastatic samples. Univariate analysis showed that INPP4B expression was indicated to have a marked association with histological grades, tumor size and tumor metastasis. Moreover, INPP4B overexpression suppressed cell proliferation, migration, invasion and EMT, but induced cell apoptosis and chemosensitivity in human HCC cell lines. In contrast, INPP4B knockdown had the opposite effects on the biological behaviors of HCC cells. Furthermore, INPP4B was found to inhibit the activation of PI3K/Akt signaling in HCC cells.

Conclusion: Our findings suggest that INPP4B is a tumor suppressing gene in human HCC, and might act as a novel therapeutic target for HCC patients.

The PEAK1-PPP1R12B axis inhibits tumor growth and metastasis by regulating Grb2/PI3K/Akt signalling in colorectal cancer

Pseudopodium enriched atypical kinase 1 (PEAK1), a novel non-receptor tyrosine kinase, was recently implicated in cancer pathogenesis. However, its functional role in colorectal cancer (CRC) is not well known. Herein, we demonstrated that PEAK1 was frequently downregulated in CRC and significantly associated with tumor size, differentiation status, metastasis, and clinical stage. PEAK1 overexpression suppressed CRC cell growth, invasion, and metastasis in vitro and in vivo, whereas knockout had the opposite effects. Further evaluation revealed that PEAK1 expression was positively correlated with protein phosphatase 1 regulatory subunit 12B (PPP1R12B) in CRC cell lines and clinical tissues, and this protein was found to suppress activation of the Grb2/PI3K/Akt pathway. Moreover, PPP1R12B knockdown markedly abrogated PEAK1-mediated tumor suppressive effects, whereas its upregulation recapitulated the effects of PEAK1 knockout on cell behaviours and the activation of signalling. Mechanistically, PI3K and Akt inhibitors reversed impaired the effect of PEAK1 function on cell proliferation, migration, and invasion. Our results provide compelling evidence that the PEAK1-PPP1R12B axis inhibits colorectal tumorigenesis and metastasis through deactivation of the Grb2/PI3K/Akt pathway, which might provide a novel therapeutic strategy for CRC treatment.

Downregulation of RNF138 inhibits cellular proliferation, migration, invasion and EMT in glioma cells via suppression of the Erk signaling pathway

Glioma is the most common adult malignant primary brain tumor; however, the effect of chemotherapy is often limited by drug‑resistance and poor prognosis is common. Ring finger protein 138 (RNF138) belongs to the E3 ligase family, and has significantly higher expression level in glioma tissue than in noncancerous brain tissues. Epithelial-mesenchymal-transition (EMT) has a critical role in cancer invasion and metastasis, ultimately leading to increased cell motility and resistance to genotoxic agents. Extracellular‑signal regulated kinase (Erk) pathways promote the growth of glioma cells and enhance tumor invasion, with a role in the progression of EMT. However, the association between RNF138 and human glioma progression remains poorly understood. Relatively little is known about the association between RNF138, Erk, and EMT in glioma progression. In the current study, experiments were performed to explore the potential roles and mechanisms of RNF138 in glioblastoma in vitro and in vivo. Glioma cell line proliferation, migration and invasion were inhibited by knockdown of RNF138 in vitro. By lowering the RNF138 expression, cleaved caspase3 and E‑cadherin were upregulated, while phospho‑Erk1/2, vimentin, MMP2, HIF‑1α and VEGF were downregulated in U87 and U251 cells in vitro. In vivo findings revealed that the growth of U87 cell‑transplanted tumors in nude mice was inhibited in tumors with RNF138 knockdown. These findings suggested that downregulation of RNF138 inhibited glioma cell proliferation, migration, and invasion, and reversed EMT, potentially via Erk signaling pathway. Therefore, RNF138 may be a potential therapeutic target against glioma.