FER tyrosine kinase (FER) overexpression mediates resistance to quinacrine through EGF-dependent activation of NF-kappaB

Decorin impeded the advancement of thyroid papillary carcinoma by thwarting the EGFR/ FER/ SHP2 signaling-induced sustenance of early endosomes

Objective

This study explores the inhibition of papillary thyroid carcinoma proliferation by Decorin via the EGFR/SHP2/FER pathway.

Method

ology: Thirty-two pairs of papillary thyroid carcinoma tissues and adjacent normal tissues were collected for immunohistochemical analysis. Thyroid cancer cell lines with overexpressed or silenced Decorin were employed in subcutaneous tumor formation experiments in nude mice. Cell membrane proteins were extracted for Western blot and immunofluorescence analyses.

Results

Reduced Decorin expression in human papillary thyroid carcinoma was associated with inhibited formation of the EGFR/SHP2/FER complex. Immunohistochemical analysis revealed lower Decorin levels in carcinoma tissues compared to adjacent normal tissues, corroborated by decreased Decorin and PTEN levels in carcinoma as shown by Western Blot. Overexpression of Decorin in mouse models diminished tumor growth, an effect reversed by Decorin silencing and mitigated by FER inhibition. Decorin modulated Rab5-GTP and Rab7-GTP levels, impacting endosome transition and subsequent signaling pathways.

Conclusion

Decorin inhibits papillary thyroid carcinoma proliferation by disrupting the EGFR/SHP2/FER pathway and modulating endosomal transport.

Optimization of Novel Pyrido-pyridazinone Derivatives as FER Tyrosine Kinase Inhibitors, Leading to the Potent DS08701581

Previously, we reported the new pyrido-pyridazinone template as a feline sarcoma-related (FER) tyrosine kinase inhibitor. Representative compound 1 (DS21360717) showed strong enzyme inhibitory activity (IC50 = 0.5 nM), however, its antitumor effect was insufficient, probably due to poor solubility and resultant low bioavailability (BA). In addition, the kinase selectivity was inadequate, which may result in certain safety risks. Here, we focused on derivatization of the unoptimized C-5 position to obtain promising FER inhibitors possessing strong antitumor effects and improved selectivity, referring to their X-ray crystal structure and the docking model with FES proto-oncogene tyrosine kinase as an FER surrogate. While establishing the synthetic route of the pyrido-pyridazinone scaffold, we obtained a desired compound via our derivatization. Our optimized compound 17c (DS08701581) showed the highest class cell-free and cell activities in this template, good oral BA, and improved kinase selectivity, resulting in significant tumor growth inhibition in the Ba/F3-FER tumor model without body weight loss.

The Molecular and Genetic Interactions between Obesity and Breast Cancer Risk

Breast cancer (BC) is considered the leading cause of death among females worldwide. Various risk factors contribute to BC development, such as age, genetics, reproductive factors, obesity, alcohol intake, and lifestyle. Obesity is considered to be a pandemic health problem globally, affecting millions of people worldwide. Obesity has been associated with a high risk of BC development. Determining the impact of obesity on BC development risk in women by demonstrating the molecular and genetic association in pre- and post-menopause females and risk to BC initiation is crucial in order to improve the diagnosis and prognosis of BC disease. In epidemiological studies, BC in premenopausal women was shown to be protective in a certain pattern. These altered effects between the two phases could be due to various physiological changes, such as estrogen/progesterone fluctuating levels. In addition, the relationship between BC risk and obesity is indicated by different molecular alterations as metabolic pathways and genetic mutation or epigenetic DNA changes supporting a strong connection between obesity and BC risk. However, these molecular and genetic alteration remain incompletely understood. The aim of this review is to highlight and elucidate the different molecular mechanisms and genetic changes occurring in obese women and their association with BC risk and development.

Quinacrine inhibits cMET-mediated metastasis and angiogenesis in breast cancer stem cells

A trans-membrane receptor tyrosine kinase, cMET, belonging to the MET proto-oncogene family, is responsible for cancer metastasis and angiogenesis. But not much is known about the role of cMET in growth and progression of cancer stem cells (CSCs). Earlier studies have shown that Quinacrine (QC), a bioactive agent, has anti-CSCs activity. Here, the role of QC in deregulation of cMET-mediated metastasis and angiogenesis has been systematically evaluated in vitro in highly metastatic breast CSCs (mBCSCs), ex vivo in patient-derived breast cancer stem cells (PDBCSCs) and in vivo in xenograft mice model systems. Cell proliferation, migration, invasion and representative metastasis markers were upregulated in cMET-overexpressed cells and QC exposure inhibited these processes in both mBCSCs and PDBCSCs. Interestingly, metastasis was significantly inhibited by QC in cMET-overexpressed cells but comparatively lesser significant alteration of the process was noted in cMET-silenced cells. Increase in vascularization (in in ovo CAM assay), and cell-cell tube formation (in HUVECs), and enhanced MMP9 and MMP2 enzymatic activities (in gelatin zymography) were noted after cMET overexpression but these processes got reversed after cMET knockdown or QC treatment in cMET-overexpressed cells. QC inhibited angiogenesis significantly in cMET-overexpressed cells, but lesser significant change was observed in cMET-silenced cells. Reduction in tumor volume and decreased expression of metastatic and angiogenic markers were also noted in xenograft mice after QC treatment. Furthermore, QC inhibited cMET activity by dephosphorylation of its tyrosine residues (Y1234 and Y1356) and downregulation of its downstream cascade. Thus, QC inhibited the cMET-mediated metastasis and angiogenesis in in vitro, in ovo, in vivo and ex vivo model systems. Ligand (HGF) binding leads to receptor dimerization and phosphorylation of tyrosine kinase domain of cMET. This activates the cMET signaling cascade. The representative downstream metastasis and angiogenesis-related proteins get upregulated and induce the metastasis and angiogenesis process. But after the QC treatment, cMET get dephosphorylated and inactivated. As a result, the downstream signaling proteins of cMET along with the other representative metastatic and angiogenic factors get downregulated. These lead to inhibition of cMET-mediated metastasis and angiogenesis. (Created with BioRender.com).

SKOR1 mediates FER kinase-dependent invasive growth of breast cancer cells

High expression of the non-receptor tyrosine kinase FER is an independent prognostic factor that correlates with poor survival in breast cancer patients. To investigate whether the kinase activity of FER is essential for its oncogenic properties, we developed an ATP analogue-sensitive knock-in allele (FERASKI). Specific FER kinase inhibition in MDA-MB-231 cells reduces migration and invasion, as well as metastasis when xenografted into a mouse model of breast cancer. Using the FERASKI system, we identified Ski family transcriptional corepressor 1 (SKOR1) as a direct FER kinase substrate. SKOR1 loss phenocopies FER inhibition, leading to impaired proliferation, migration and invasion, and inhibition of breast cancer growth and metastasis formation in mice. We show that SKOR1 Y234, a candidate FER phosphorylation site, is essential for FER-dependent tumor progression. Finally, our work suggests that the SKOR1 Y234 residue promotes Smad2/3 signaling through SKOR1 binding to Smad3. Our study thus identifies SKOR1 as a mediator of FER-dependent progression of high-risk breast cancers.

Integrated genomic analyses of acral and mucosal melanomas nominate novel driver genes

BACKGROUND

Acral and mucosal melanomas are aggressive subtypes of melanoma, which have a significantly lower burden of somatic mutations than cutaneous melanomas, but more frequent copy number variations, focused gene amplifications, and structural alterations. The landscapes of their genomic alterations remain to be fully characterized.

METHODS

We compiled sequencing data of 240 human acral and mucosal melanoma samples from 11 previously published studies and applied a uniform pipeline to call tumor cell content, ploidy, somatic and germline mutations, as well as CNVs, LOH, and SVs. We identified genes that are significantly mutated or recurrently affected by CNVs and implicated in oncogenesis. We further examined the difference in the frequency of recurrent pathogenic alterations between the two melanoma subtypes, correlation between pathogenic alterations, and their association with clinical features.

RESULTS

We nominated PTPRJ, mutated and homozygously deleted in 3.8% (9/240) and 0.8% (2/240) of samples, respectively, as a probable tumor suppressor gene, and FER and SKP2, amplified in 3.8% and 11.7% of samples, respectively, as probable oncogenes. We further identified a long tail of infrequent pathogenic alterations, involving genes such as CIC and LZTR1. Pathogenic germline mutations were observed on MITF, PTEN, ATM, and PRKN. We found BRAF V600E mutations in acral melanomas with fewer structural variations, suggesting that they are distinct and related to cutaneous melanomas. Amplifications of PAK1 and GAB2 were more commonly observed in acral melanomas, whereas SF3B1 R625 codon mutations were unique to mucosal melanomas (12.9%). Amplifications at 11q13-14 were frequently accompanied by fusion to a region on chromosome 6q12, revealing a recurrent novel structural rearrangement whose role remains to be elucidated.

CONCLUSIONS

Our meta-analysis expands the catalog of driver mutations in acral and mucosal melanomas, sheds new light on their pathogenesis and broadens the catalog of therapeutic targets for these difficult-to-treat cancers.

FER regulates endosomal recycling and is a predictor for adjuvant taxane benefit in breast cancer

Elevated expression of non-receptor tyrosine kinase FER is an independent prognosticator that correlates with poor survival of high-grade and basal/triple-negative breast cancer (TNBC) patients. Here, we show that high FER levels are also associated with improved outcomes after adjuvant taxane-based combination chemotherapy in high-risk, HER2-negative patients. In TNBC cells, we observe a causal relation between high FER levels and sensitivity to taxanes. Proteomics and mechanistic studies demonstrate that FER regulates endosomal recycling, a microtubule-dependent process that underpins breast cancer cell invasion. Using chemical genetics, we identify DCTN2 as a FER substrate. Our work indicates that the DCTN2 tyrosine 6 is essential for the development of tubular recycling domains in early endosomes and subsequent propagation of TNBC cell invasion in 3D. In conclusion, we show that high FER expression promotes endosomal recycling and represents a candidate predictive marker for the benefit of adjuvant taxane-containing chemotherapy in high-risk patients, including TNBC patients.

Development of Dual Inhibitors Targeting Epidermal Growth Factor Receptor in Cancer Therapy

Epidermal growth factor receptor (EGFR) is of great significance in mediating cell signaling transduction and tumor behaviors. Currently, third-generation inhibitors of EGFR, especially osimertinib, are at the clinical frontier for the treatment of EGFR-mutant non-small-cell lung cancer (NSCLC). Regrettably, the rapidly developing drug resistance caused by EGFR mutations and the compensatory mechanism have largely limited their clinical efficacy. Given the synergistic effect between EGFR and other compensatory targets during tumorigenesis and tumor development, EGFR dual-target inhibitors are promising for their reduced risk of drug resistance, higher efficacy, lower dosage, and fewer adverse events than those of single-target inhibitors. Hence, we present the synergistic mechanism underlying the role of EGFR dual-target inhibitors against drug resistance, their structure-activity relationships, and their therapeutic potential. Most importantly, we emphasize the optimal target combinations and design strategies for EGFR dual-target inhibitors and provide some perspectives on new challenges and future directions in this field.

Validation-Based Insertional Mutagenesis (VBIM), A Powerful Forward Genetic Screening Strategy

Forward genetics begins with a biological phenotype and attempts to identify genetic changes that influence that phenotype. These changes can be induced in a selected group of genes, for instance, by using libraries of cDNAs, shRNAs, CRISPR guide RNAs, or genetic suppressor elements (GSEs), or randomly throughout the genome using chemical or insertional mutagens, with each approach creating distinct genetic changes. The Validation-Based Insertional Mutagenesis (VBIM) strategy utilizes modified lentiviruses as insertional mutagens, placing strong promoters throughout the genome. Generating libraries with millions of cells carrying one or a few VBIM promoter insertions is straightforward, allowing selection of cells in which overexpression of VBIM-driven RNAs or proteins promote the phenotype of interest. VBIM-driven RNAs may encode full-length proteins, truncated proteins (which may have wild-type, constitutive, or dominant-negative activity), or antisense RNAs that can disrupt gene expression. The diversity in VBIM-driven changes allows for the identification of both gain-of-function and loss-of-function mutations in a single screen. Additionally, VBIM can target any genomic locus, regardless of whether it is expressed in the cells under study or known to have a biological function, allowing for true whole-genome screens without the complication and cost of constructing, maintaining, and delivering a comprehensive library. Here, we review the VBIM strategy and discuss examples in which VBIM has been successfully used in diverse screens to identify novel genes or novel functions for known genes. In addition, we discuss considerations for transitioning the VBIM strategy to in vivo screens. We hope that other laboratories will be encouraged to use the VBIM strategy to identify genes that influence their phenotypes of interest. © 2022 Wiley Periodicals LLC.

Interactions Between Adiponectin-Pathway Polymorphisms and Obesity on Postmenopausal Breast Cancer Risk Among African American Women: The WHI SHARe Study

BACKGROUND

A decreased level of serum adiponectin is associated with obesity and an increased risk of breast cancer among postmenopausal women. Yet, the interplay between genetic variants associated with adiponectin phenotype, obesity, and breast cancer risk is unclear in African American (AA) women.

METHODS

We examined 32 single-nucleotide polymorphisms (SNPs) previously identified in genome-wide association and replication studies of serum adiponectin levels using data from 7,991 AA postmenopausal women in the Women's Health Initiative SNP Health Association Resource.

RESULTS

Stratifying by obesity status, we identified 18 adiponectin-related SNPs that were associated with breast cancer risk. Among women with BMI ≥ 30 kg/m2, the minor TT genotype of FER rs10447248 had an elevated breast cancer risk. Interaction was observed between obesity and the CT genotype of ADIPOQ rs6773957 on the additive scale for breast cancer risk (relative excess risk due to interaction, 0.62; 95% CI, 0.32-0.92). The joint effect of BMI ≥ 30 kg/m2 and the TC genotype of OR8S1 rs11168618 was larger than the sum of the independent effects on breast cancer risk.

CONCLUSIONS

We demonstrated that obesity plays a significant role as an effect modifier in an increased effect of the SNPs on breast cancer risk using one of the most extensive data on postmenopausal AA women.

IMPACT

The results suggest the potential use of adiponectin genetic variants as obesity-associated biomarkers for informing AA women who are at greater risk for breast cancer and also for promoting behavioral interventions, such as weight control, to those with risk genotypes.

FER Regulated by miR-206 Promotes Hepatocellular Carcinoma Progression via NF-κB Signaling

Objectives

Feline sarcoma-related protein (FER) is known to play a critical regulatory role in several carcinomas. However, the exact biological function of FER in hepatocellular carcinoma (HCC) still needs to be investigated. The primary objective of this research was to investigate the unknown function and molecular mechanisms of FER in HCC.

Materials and Methods

The expression level of FER in HCC tissue samples and cells was examined by RT-qPCR, immunohistochemistry and western blot. Cellular and animal experiments were used to explore the effect of FER on the proliferative and metastatic capacities of HCC cells. The crosstalk between FER and NF-κB signaling was explored by western blot. The upstream factors that regulate FER were evaluated through dual-luciferase experiments and western blot assays.

Results

FER was overexpressed in HCC specimens and HCC cell lines. FER expression levels were positively associated with unfavorable clinicopathological characteristics. The higher the expression of FER was, the worse the overall survival of HCC patients was. The results of loss-of-function and gain-of-function experiments indicated that knockdown of FER decreased, while overexpression of FER increased, the proliferation, invasion and metastasis of HCC cells in vitro and in vivo. Mechanistically, we found that FER activated the NF-κB signaling pathway and stimulated epithelial-to-mesenchymal transition (EMT). We also found that FER was directly regulated by miR-206, and the downregulation of miR-206 was associated with proliferation and metastatic progression in HCC.

Conclusions

The present research was the first to reveal that a decrease in miR-206 levels results in an increase in FER expression in HCC, leading to enhanced cell growth and metastatic abilities via activation of the NF-κB signaling pathway.

Loss of ZIP facilitates JAK2-STAT3 activation in tamoxifen-resistant breast cancer

Tamoxifen is beneficial in treating estrogen receptor–positive breast cancer, but resistance to this treatment eventually ensues. A method to identify mechanisms of tamoxifen resistance identified the histone deacetylase ZIP, leading to the finding that increased expression of the tyrosine kinase JAK2 is one important factor. As a result of this discovery, it may be possible to use an inhibitor of JAK2 to block the aberrant activation of STAT3 caused by ZIP deficiency to help overcome or prevent tamoxifen resistance.

Tamoxifen, a widely used modulator of the estrogen receptor (ER), targets ER-positive breast cancer preferentially. We used a powerful validation-based insertion mutagenesis method to find that expression of a dominant-negative, truncated form of the histone deacetylase ZIP led to resistance to tamoxifen. Consistently, increased expression of full-length ZIP gives the opposite phenotype, inhibiting the expression of genes whose products mediate resistance. An important example is JAK2. By binding to two specific sequences in the promoter, ZIP suppresses JAK2 expression. Increased expression and activation of JAK2 when ZIP is inhibited lead to increased STAT3 phosphorylation and increased resistance to tamoxifen, both in cell culture experiments and in a mouse xenograft model. Furthermore, data from human tumors are consistent with the conclusion that decreased expression of ZIP leads to resistance to tamoxifen in ER-positive breast cancer.

Yeast-Based Genetic Interaction Analysis of Human Kinome

Kinases are critical intracellular signaling proteins. To better understand kinase-mediated signal transduction, a large-scale human-yeast genetic interaction screen was performed. Among 597 human kinase genes tested, 28 displayed strong toxicity in yeast when overexpressed. En masse transformation of these toxic kinase genes into 4653 homozygous diploid yeast deletion mutants followed by barcode sequencing identified yeast toxicity modifiers and thus their human orthologs. Subsequent network analyses and functional grouping revealed that the 28 kinases and their 676 interaction partners (corresponding to a total of 969 genetic interactions) are enriched in cell death and survival (34%), small-molecule biochemistry (18%) and molecular transport (11%), among others. In the subnetwork analyses, a few kinases were commonly associated with glioma, cell migration and cell death/survival. Our analysis enabled the creation of a first draft of the kinase genetic interactome network and identified multiple drug targets for inflammatory diseases and cancer, in which deregulated kinase signaling plays a pathogenic role.

New genetic variations discovered in KRAS wild-type cetuximab resistant chinese colorectal cancer patients

To perform a comprehensive genomic analysis of colorectal cancer (CRC) tumor to detect genetic variants and identify novel resistant mutations associated with cetuximab-resistance in CRC patients. A retrospective study was performed using whole exome sequencing (WES) to identify common genetic factors from 22 cetuximab-sensitive and 10 cetuximab-resistant patients. In all 10 cetuximab-resistant patients, we discovered there are 37 significantly mutated genes (SMGs). CYP4A11 was the most frequently mutated gene in cetuximab-resistant patients. BCAS1 and GOLGA6L1 were found to be among the second group of frequently mutated genes with a frequency of 60%. After cosine similarity analysis, three mutational signatures (signature a, b, and c) were found in all CRC tumors, similar to signature 1, 5, and 6 in COSMIC, respectively. Gene ontology analysis was performed on SMGs and found 12 enriched GO terms. Four genes are enriched in six specific Kyoto Encyclopedia of Genes and Genomes pathway groups, including the metabolism of xenobiotics by cytochrome P450, steroid hormone biosynthesis, retinol metabolism, and drug metabolism. Our data supports a network composed of SMGs and cellular signaling pathways that have been positively linked to the mechanisms of cetuximab resistance. These involve DNA damage repair, angiogenesis, invasion, drug metabolism, and the CRC tumor microenvironment. There is a SMG, OR9G1 correlated with survival rates of KRAS wild-type colon adenocarcinoma patients. These findings support further investigation using WES in a prospective clinical study of cetuximab resistance CRC, to further identify, confirm, and extend the clinical significance of these and other potentially important new candidate predictive biomarkers of cetuximab response.

High-resolution structural analysis shows how different crystallographic environments can induce alternative modes of binding of a phosphotyrosine peptide to the SH2 domain of Fer tyrosine kinase

Fes and Fes-related (Fer) protein tyrosine kinases (PTKs) comprise a subfamily of nonreceptor tyrosine kinases characterized by a unique multidomain structure composed of an N-terminal Fer/CIP4 homology-Bin/Amphiphysin/Rvs (F-BAR) domain, a central Src homology 2 (SH2) domain, and a C-terminal PTK domain. Fer is ubiquitously expressed, and upregulation of Fer has been implicated in various human cancers. The PTK activity of Fes has been shown to be positively regulated by the binding of phosphotyrosine-containing ligands to the SH2 domain. Here, the X-ray crystal structure of human Fer SH2 domain bound to a phosphopeptide that has D-E-pY-E-N-V-D sequence is reported at 1.37 å resolution. The asymmetric unit (ASU) contains six Fer-phosphopeptide complexes, and the structure reveals three distinct binding modes for the same phosphopeptide. At four out of the six binding sites in the ASU, the phosphopeptide binds to Fer SH2 domain in a type I β-turn conformation, and this could be the optimal binding mode of this phosphopeptide. At the other two binding sites in the ASU, it appears that spatial proximity of neighboring SH2 domains in the crystal induces alternative modes of binding of this phosphopeptide.

FER promotes cell migration via regulating JNK activity

Objectives

Cell migration has a key role in cancer metastasis, which contributes to drug resistance and tumour recurrence. Better understanding of the mechanisms involved in this process will potentially reveal new drug targets for cancer therapy. Fer is a non‐receptor protein tyrosine kinase aberrantly expressed in various human cancers, whereas its role in tumour progression remains elusive.

Materials and Methods

Transgenic flies and epigenetic analysis were employed to investigate the role of Drosophila Fer (FER) in cell migration and underlying mechanisms. Co‐immunoprecipitation assay was used to monitor the interaction between FER and Drosophila JNK (Bsk). The conservation of Fer in regulating JNK signalling was explored in mammalian cancer and non‐cancer cells.

Results

Overexpression of FER triggered cell migration and activated JNK signalling in the Drosophila wing disc. Upregulation and downregulation in the basal activity of Bsk exacerbated and eliminated FER‐mediated migration, respectively. In addition, loss of FER blocked signal transduction of the JNK pathway. Specifically, FER interacted with and promoted the activity of Bsk, which required both the kinase domain and the C‐terminal of Bsk. Lastly, Fer regulated JNK activities in mammalian cells.

Conclusions

Our study reveals FER as a positive regulator of JNK‐mediated cell migration and suggests its potential role as a therapeutic target for cancer metastasis.

miR-7 Suppresses Tumor Progression by Directly Targeting MAP3K9 in Pancreatic Cancer

Extensive research has suggested that miR-7 plays a critical role in cancer progression. However, the biological function of miR-7 in pancreatic cancer (PC) progression is poorly understood. Therefore, in the present study, we investigated the function of miR-7 and its molecular mechanism in PC progression. We used multiple methods, such as MTT, FACS, Transwell assay, RT-PCR, western blotting, and transfection to investigate the role of miR-7 in PC cells. We found that miR-7 suppressed cell growth, migration, and invasion but induced apoptosis in PC cells. Moreover, overexpression of miR-7 repressed tumor growth in mice, suggesting that miR-7 could exert its tumor-suppressive function in PC. Mechanistically, we validated that MAP3K9 is a direct target of miR-7, which significantly enhanced PC cell proliferation and inhibited cell apoptosis partly through activation of the MEK/ERK pathway and NF-κB pathway. Moreover, rescue experiments also showed that miR-7 suppressed PC cell proliferation and induced PC cell apoptosis by directly targeting MAP3K9, leading to inhibition of the MEK/ERK and NF-κB pathways. Taken together, these results suggest that miR-7/MAP3K9 is critically involved in PC progression and that miR-7 may be a potential target for PC treatment.

Quinacrine Inhibits ICAM-1 Transcription by Blocking DNA Binding of the NF-κB Subunit p65 and Sensitizes Human Lung Adenocarcinoma A549 Cells to TNF-α and the Fas Ligand

Quinacrine has been used for therapeutic drugs in some clinical settings. In the present study, we demonstrated that quinacrine decreased the expression of intercellular adhesion molecule-1 (ICAM-1) induced by tumor necrosis factor (TNF)-α and interleukin-1 (IL-1) α in human lung adenocarcinoma A549 cells. Quinacrine inhibited ICAM-1 mRNA expression and nuclear factor κB (NF-κB)-responsive luciferase reporter activity following a treatment with TNF-α and IL-1α. In the NF-κB signaling pathway, quinacrine did not markedly affect the TNF-α-induced degradation of the inhibitor of NF-κB or the TNF-α-induced phosphorylation of the NF-κB subunit, p65, at Ser-536 and its subsequent translocation to the nucleus. In contrast, a chromatin immunoprecipitation assay showed that quinacrine prevented the binding of p65 to the ICAM-1 promoter following TNF-α stimulation. Moreover, TNF-α and the Fas ligand effectively reduced the viability of A549 cells in the presence of quinacrine only. Quinacrine down-regulated the constitutive and TNF-α-induced expression of c-FLIP and Mcl-1 in A549 cells. These results revealed that quinacrine inhibits ICAM-1 transcription by blocking the DNA binding of p65 and sensitizes A549 cells to TNF-α and the Fas ligand.

MAN2A1-FER Fusion Gene Is Expressed by Human Liver and Other Tumor Types and Has Oncogenic Activity in Mice

BACKGROUND & AIMS

Human tumors and liver cancer cell lines express the product of a fusion between the first 13 exons in the mannosidase α class 2A member 1 gene (MAN2A1) and the last 6 exons in the FER tyrosine kinase gene (FER), called MAN2A1-FER. We investigated whether MAN2A1-FER is expressed by human liver tumors and its role in liver carcinogenesis.

METHODS

We performed reverse transcription polymerase chain reaction analyses of 102 non-small cell lung tumors, 61 ovarian tumors, 70 liver tumors, 156 glioblastoma multiform samples, 27 esophageal adenocarcinomas, and 269 prostate cancer samples, as well as 10 nontumor liver tissues and 20 nontumor prostate tissues, collected at the University of Pittsburgh. We also measured expression by 15 human cancer cell lines. We expressed a tagged form of MAN2A1-FER in NIH3T3 and HEP3B (liver cancer) cells; Golgi were isolated for analysis. MAN2A1-FER was also overexpressed in PC3 or DU145 (prostate cancer), NIH3T3 (fibroblast), H23 (lung cancer), and A-172 (glioblastoma multiforme) cell lines and knocked out in HUH7 (liver cancer) cells. Cells were analyzed for proliferation and in invasion assays, and/or injected into flanks of severe combined immunodeficient mice; xenograft tumor growth and metastasis were assessed. Mice with hepatic deletion of PTEN were given tail-vein injections of MAN2A1-FER.

RESULTS

We detected MAN2A1-FER messenger RNA and fusion protein (114 kD) in the hepatocellular carcinoma cell line HUH7, as well as in liver tumors, esophageal adenocarcinoma, glioblastoma multiforme, prostate tumors, non-small cell lung tumors, and ovarian tumors, but not nontumor prostate or liver tissues. MAN2A1-FER protein retained the signal peptide for Golgi localization from MAN2A1 and translocated from the cytoplasm to Golgi in cancer cell lines. MAN2A1-FER had tyrosine kinase activity almost 4-fold higher than that of wild-type FER, and phosphorylated the epidermal growth factor receptor at tyrosine 88 in its N-terminus. Expression of MAN2A1-FER in 4 cell lines led to epidermal growth factor receptor activation of BRAF, MEK, and AKT; HUH7 cells with MAN2A1-FER knockout had significant decreases in phosphorylation of these proteins. Cell lines that expressed MAN2A1-FER had increased proliferation, colony formation, and invasiveness and formed larger (>2-fold) xenograft tumors in mice, with more metastases, than cells not expressing the fusion protein. HUH7 cells with MAN2A1-FER knockout formed smaller xenograft tumors, with fewer metastases, than control HUH7 cells. HUH7, A-172, and PC3 cells that expressed MAN2A1-FER were about 2-fold more sensitive to the FER kinase inhibitor crizotinib and the epidermal growth factor receptor kinase inhibitor canertinib; these drugs slowed growth of xenograft tumors from MAN2A1-FER cells and prevented their metastasis in mice. Hydrodynamic tail-vein injection of MAN2A1-FER resulted in rapid development of liver cancer in mice with hepatic disruption of Pten.

CONCLUSIONS

Many human tumor types and cancer cell lines express the MAN2A1-FER fusion, which increases proliferation and invasiveness of cancer cell lines and has liver oncogenic activity in mice.

Control of cancer stem cell like population by intracellular target identification followed by the treatment with peptide-siRNA complex

Cancer stem cells (CSCs) are a subpopulation of cancer cells and have been known to create cancer reoccurrence during cancer therapy due to their stem cell-like characteristics. However, exact target to control the CSC has not been fully established. Here, we enriched CD44^High population of MDA-MB-231 cells by CD44 antibody as a CSC marker. By Phospho Antibody Array, CD44^High population of MDA-MB-231 cells reveals Feline sarcoma-related tyrosine kinase (FER) protein was highly activated. When FER siRNA and low molecular weight protamine (LMWP) as cell penetrating peptides are applied to this population, cancer migration and colony forming ability are inhibited. Moreover, silencing FER using FER siRNA and LMWP conjugates enhances anti-metastasis related factors including E-cadherin, p75 and p63. Taken together, FER is a new marker for targeting breast CSCs and peptide-mediated siRNA method could be an effective and safe way of delivery and be a new therapeutic strategy for targeting breast cancer.

HGF-independent regulation of MET and GAB1 by nonreceptor tyrosine kinase FER potentiates metastasis in ovarian cancer

In this study, Fan et al. report a novel ligand- and autophosphorylation-independent activation of MET through the nonreceptor tyrosine kinase FER. The findings show that levels of FER were elevated in ovarian cancer cell lines and that loss of FER impaired the metastasis of ovarian cancer cells in vivo, providing new insights into signaling events that underlie metastasis in ovarian cancer cells.

Ovarian cancer cells disseminate readily within the peritoneal cavity, which promotes metastasis, and are often resistant to chemotherapy. Ovarian cancer patients tend to present with advanced disease, which also limits treatment options; consequently, new therapies are required. The oncoprotein tyrosine kinase MET, which is the receptor for hepatocyte growth factor (HGF), has been implicated in ovarian tumorigenesis and has been the subject of extensive drug development efforts. Here, we report a novel ligand- and autophosphorylation-independent activation of MET through the nonreceptor tyrosine kinase feline sarcoma-related (FER). We demonstrated that the levels of FER were elevated in ovarian cancer cell lines relative to those in immortalized normal surface epithelial cells and that suppression of FER attenuated the motility and invasive properties of these cancer cells. Furthermore, loss of FER impaired the metastasis of ovarian cancer cells in vivo. Mechanistically, we demonstrated that FER phosphorylated a signaling site in MET: Tyr1349. This enhanced activation of RAC1/PAK1 and promoted a kinase-independent scaffolding function that led to recruitment and phosphorylation of GAB1 and the specific activation of the SHP2–ERK signaling pathway. Overall, this analysis provides new insights into signaling events that underlie metastasis in ovarian cancer cells, consistent with a prometastatic role of FER and highlighting its potential as a novel therapeutic target for metastatic ovarian cancer.

The ubiquitin ligase Cullin5SOCS2 regulates NDR1/STK38 stability and NF-κB transactivation

SOCS2 is a pleiotropic E3 ligase. Its deficiency is associated with gigantism and organismal lethality upon inflammatory challenge. However, mechanistic understanding of SOCS2 function is dismal due to our unawareness of its protein substrates. We performed a mass spectrometry based proteomic profiling upon SOCS2 depletion and yield quantitative data for ~4200 proteins. Through this screen we identify a novel target of SOCS2, the serine-threonine kinase NDR1. Over-expression of SOCS2 accelerates turnover, while its knockdown stabilizes, endogenous NDR1 protein. SOCS2 interacts with NDR1 and promotes its degradation through K48-linked ubiquitination. Functionally, over-expression of SOCS2 antagonizes NDR1-induced TNFα-stimulated NF-κB activity. Conversely, depletion of NDR1 rescues the effect of SOCS2-deficiency on TNFα-induced NF-κB transactivation. Using a SOCS2^−/− mice model of colitis we show that SOCS2-deficiency is pro-inflammatory and negatively correlates with NDR1 and nuclear p65 levels. Lastly, we provide evidence to suggest that NDR1 acts as an oncogene in prostate cancer. To the best of our knowledge, this is the first report of an identified E3 ligase for NDR1. These results might explain how SOCS2-deficiency leads to hyper-activation of NF-κB and downstream pathological implications and posits that SOCS2 induced degradation of NDR1 may act as a switch in restricting TNFα-NF-κB pathway.

Inactivation of M2 AChR/NF-κB signaling axis reverses epithelial-mesenchymal transition (EMT) and suppresses migration and invasion in non-small cell lung cancer (NSCLC)

Non-neuronal cholinergic system is involved in lung physiology and lung cancer. However, the biochemical events downstream acetylcholine (ACh) receptor activation leading to carcinogenesis and tumor progression are not fully understood. Our previous work has shown that non-neuronal ACh acts as an autoparacrine growth factor to stimulate cell proliferation and promote epithelial-mesenchymal transition (EMT) in non-small cell lung cancer (NSCLC) via activation of M2 muscarinic receptor (M2R). The aim of the present study was to delineate the underlying mechanisms linking M2R and lung tumor progression, which may provide potential therapeutic targets to delay lung cancer progression. Inhibition of M2R by antagonist or siRNA suppresses NSCLC cell migratory and invasive capacities, reverses EMT and simultaneously inactivates PI3K/Akt, MAPK ERK and NF-κB p65. On the other hand, M2R activation stimulates NSCLC migration and invasion and promotes EMT via NF-κB p65 activation. Moreover, NF-κB p65 activation induced by M2R activation was partially inhibited by either Akt or ERK inhibitor. Taken together, these results demonstrated for the first time that NF-κB p65 activation is essential in NSCLC progression associated with non-neuronal cholinergic system. Our data suggest that M2R/ERK/Akt/NF-κB axis could be a potential target for NSCLC treatment.

Asymmetric Wnt Pathway Signaling Facilitates Stem Cell-Like Divisions via the Nonreceptor Tyrosine Kinase FRK-1 in Caenorhabditis elegans

Asymmetric cell division is critical during development, as it influences processes such as cell fate specification and cell migration. We have characterized FRK-1, a homolog of the mammalian Fer nonreceptor tyrosine kinase, and found it to be required for differentiation and maintenance of epithelial cell types, including the stem cell-like seam cells of the hypodermis. A genomic knockout of frk-1, allele ok760, results in severely uncoordinated larvae that arrest at the L1 stage and have an excess number of lateral hypodermal cells that appear to have lost asymmetry in the stem cell-like divisions of the seam cell lineage. frk-1(ok760) mutants show that there are excess lateral hypodermal cells that are abnormally shaped and smaller in size compared to wild type, a defect that could be rescued only in a manner dependent on the kinase activity of FRK-1. Additionally, we observed a significant change in the expression of heterochronic regulators in frk-1(ok760) mutants. However, frk-1(ok760) mutants do not express late, nonseam hypodermal GFP markers, suggesting the seam cells do not precociously differentiate as adult-hyp7 cells. Finally, our data also demonstrate a clear role for FRK-1 in seam cell proliferation, as eliminating FRK-1 during the L3-L4 transition results in supernumerary seam cell nuclei that are dependent on asymmetric Wnt signaling. Specifically, we observe aberrant POP-1 and WRM-1 localization that is dependent on the presence of FRK-1 and APR-1. Overall, our data suggest a requirement for FRK-1 in maintaining the identity and proliferation of seam cells primarily through an interaction with the asymmetric Wnt pathway.

Discovery and Classification of Fusion Transcripts in Prostate Cancer and Normal Prostate Tissue

Fusion transcript formation is one of the fundamental mechanisms that drives the development of prostate cancer. Because of the advance of high-throughput parallel sequencing, many fusion transcripts have been discovered. However, the discovery rate of fusion transcripts specific for prostate cancer is lagging behind the discoveries made on chromosome abnormalities of prostate cancer. Recent analyses suggest that many fusion transcripts are present in both benign and cancerous tissues. Some of these fusion transcripts likely represent important components of normal gene expression in cells. It is necessary to identify the criteria and features of fusion transcripts that are specific for cancer. In this review, we discuss optimization of RNA sequencing depth for fusion transcript discovery and the characteristics of fusion transcripts in normal prostate tissues and prostate cancer. We also propose a new classification of cancer-specific fusion transcripts on the basis of their tail gene fusion protein product and the roles that these fusions may play in cancer development.

Fer tyrosine kinase oligomer mediates and amplifies Src-induced tumor progression

c-Src is upregulated in various human cancers, suggesting its role in malignant progression. However, the molecular circuits of c-Src oncogenic signaling remain elusive. Here we show that Fer tyrosine kinase oligomer mediates and amplifies Src-induced tumor progression. Previously, we showed that transformation of fibroblasts is promoted by the relocation of c-Src to non-raft membranes. In this study, we identified Fer and ezrin as non-raft c-Src targets. c-Src directly activated Fer by initiating its autophosphorylation, which was further amplified by Fer oligomerization. Fer interacted with active c-Src at focal adhesion membranes and activated Fer-phosphorylated ezrin to induce cell transformation. Fer was also crucial for cell transformation induced by v-Src or epidermal growth-factor receptor activation. Furthermore, Fer activation was required for tumorigenesis and invasiveness in some cancer cells in which c-Src is upregulated. We propose that the Src-Fer axis represents a new therapeutic target for treatment of a subset of human cancers.

Combined efficacy of cediranib and quinacrine in glioma is enhanced by hypoxia and causally linked to autophagic vacuole accumulation

We have previously reported that the in vivo anti-glioma efficacy of the anti-angiogenic receptor tyrosine kinase inhibitor cediranib is substantially enhanced via combination with the late-stage autophagy inhibitor quinacrine. The current study investigates the role of hypoxia and autophagy in combined cediranib/quinacrine efficacy. EF5 immunostaining revealed a prevalence of hypoxia in mouse intracranial 4C8 glioma, consistent with high-grade glioma. MTS cell viability assays using 4C8 glioma cells revealed that hypoxia potentiated the efficacy of combined cediranib/quinacrine: cell viability reductions induced by 1 µM cediranib +2.5 µM quinacrine were 78±7% (hypoxia) vs. 31±3% (normoxia), p<0.05. Apoptosis was markedly increased for cediranib/quinacrine/hypoxia versus all other groups. Autophagic vacuole biomarker LC3-II increased robustly in response to cediranib, quinacrine, or hypoxia. Combined cediranib/quinacrine increased LC3-II further, with the largest increases occurring with combined cediranib/quinacrine/hypoxia. Early stage autophagy inhibitor 3-MA prevented LC3-II accumulation with combined cediranib/quinacrine/hypoxia and substantially attenuated the associated reduction in cell viability. Combined efficacy of cediranib with bafilomycin A1, another late-stage autophagy inhibitor, was additive but lacked substantial potentiation by hypoxia. Substantially lower LC3-II accumulation was observed with bafilomycin A1 in comparison to quinacrine. Cediranib and quinacrine each strongly inhibited Akt phosphoryation, while bafilomycin A1 had no effect. Our results provide compelling evidence that autophagic vacuole accumulation plays a causal role in the anti-glioma cytotoxic efficacy of combined cediranib/quinacrine. Such accumulation is likely related to stimulation of autophagosome induction by hypoxia, which is prevalent in the glioma tumor microenvironment, as well as Akt signaling inhibition from both cediranib and quinacrine. Quinacrine's unique ability to inhibit both Akt and autophagic vacuole degradation may enhance its ability to drive cytotoxic autophagic vacuole accumulation. These findings provide a rationale for a clinical evaluation of combined cediranib/quinacrine therapy for malignant glioma.

Extending in silico mechanism-of-action analysis by annotating targets with pathways: application to cellular cytotoxicity readouts

Background: An in silico mechanism-of-action analysis protocol was developed, comprising molecule bioactivity profiling, annotation of predicted targets with pathways and calculation of enrichment factors to highlight targets and pathways more likely to be implicated in the studied phenotype. Results: The method was applied to a cytotoxicity phenotypic endpoint, with enriched targets/pathways found to be statistically significant when compared with 100 random datasets. Application on a smaller apoptotic set (10 molecules) did not allowed to obtain statistically relevant results, suggesting that the protocol requires modification such as analysis of the most frequently predicted targets/annotated pathways. Conclusion: Pathway annotations improved the mechanism-of-action information gained by target prediction alone, allowing a better interpretation of the predictions and providing better mapping of targets onto pathways.

EGF receptor uses SOS1 to drive constitutive activation of NFκB in cancer cells

Activation of nuclear factor κB (NFκB) is a central event in the responses of normal cells to inflammatory signals, and the abnormal constitutive activation of NFκB is important for the survival of most cancer cells. In nonmalignant human cells, EGF stimulates robust activation of NFκB. The kinase activity of the EGF receptor (EGFR) is required, because the potent and specific inhibitor erlotinib blocks the response. Down-regulating EGFR expression or inhibiting EGFR with erlotinib impairs constitutive NFκB activation in several different types of cancer cells and, conversely, increased activation of NFκB leads to erlotinib resistance in these cells. We conclude that EGF is an important mediator of NFκB activation in cancer cells. To explore the mechanism, we selected an erlotinib-resistant cell line in which the guanine nucleotide exchange factor Son of Sevenless 1 (SOS1), well known to be important for EGF-dependent signaling to MAP kinases, is overexpressed. Increased expression of SOS1 increases NFκB activation in several different types of cancer cells, and ablation of SOS1 inhibits EGF-induced NFκB activation in these cells, indicating that SOS1 is a functional component of the pathway connecting EGFR to NFκB activation. Importantly, the guanine nucleotide exchange activity of SOS1 is not required for NFκB activation.

FER kinase promotes breast cancer metastasis by regulating α6- and β1-integrin-dependent cell adhesion and anoikis resistance

Metastatic breast cancer cannot be treated successfully. Currently, the targeted therapies for metastatic disease are limited to human epidermal growth factor receptor 2 and hormone receptor antagonists. Understanding the mechanisms of breast cancer growth and metastasis is therefore crucial for the development of new intervention strategies. Here, we show that FER kinase (FER) controls migration and metastasis of invasive human breast cancer cell lines by regulating α₆- and β₁-integrin-dependent adhesion. Conversely, the overexpression of FER in non-metastatic breast cancer cells induces pro-invasive features. FER drives anoikis resistance, regulates tumour growth and is necessary for metastasis in a mouse model of human breast cancer. In human invasive breast cancer, high FER expression is an independent prognostic factor that correlates with high-grade basal/triple-negative tumours and worse overall survival, especially in lymph node-negative patients. These findings establish FER as a promising target for the prevention and inhibition of metastatic breast cancer.

Fer protein-tyrosine kinase promotes lung adenocarcinoma cell invasion and tumor metastasis

Epidermal growth factor receptor (EGFR) is frequently amplified or mutated in non-small cell lung cancer (NSCLC). Although Fer protein-tyrosine kinase signals downstream of EGFR, its role in NSCLC tumor progression has not been reported. Here, Fer kinase was elevated in NSCLC tumors compared to normal lung epithelium. EGFR signaling in NSCLC cells fosters rapid Fer activation and increased localization to lamellipodia. Stable silencing of Fer in H1299 lung adenocarcinoma cells (Fer KD) caused impaired EGFR-induced lamellipodia formation compared to control cells. Fer KD NSCLC cells showed reduced Vav2 tyrosine phosphorylation that was correlated with direct Fer-mediated phosphorylation of Vav2 on tyrosine-172, which was previously reported to increase the guanine nucleotide exchange factor activity of Vav2. Indeed, Fer KD cells displayed defects in Rac-GTP localization to lamellipodia, cell migration, and cell invasion in vitro. To test the role of Fer in NSCLC progression and metastasis, control and Fer KD cells were grown as subcutaneous tumors in mice. Although Fer was not required for tumor growth, Fer KD tumor-bearing mice had significantly fewer numbers of spontaneous metastases. Combined, these data demonstrate that Fer kinase is elevated in NSCLC tumors and is important for cellular invasion and metastasis.

IMPLICATIONS

Fer protein-tyrosine kinase is a potential therapeutic target in metastatic lung cancer. Mol Cancer Res; 11(8); 952-63. ©2013 AACR.

A system for reconstructing B cell antigen receptor signaling in the mouse myeloma J558L cell line

B cell antigen receptor (BCR) signaling is positively and negatively regulated by various cell surface receptors such as CD19 and CD45. Functional analysis of these receptors has been performed using gene targeting technology, which is a valid approach to elucidate their functions. However, this type of analysis is restricted when multiple molecules are evaluated simultaneously. From a different perspective, synthetic biology provides a high degree of freedom for analyzing various molecules. Here we developed a system to reconstruct BCR signaling using the J558L myeloma cell line in combination with the protein-based Ca(2+) indicator YC3.60. BCR-reconstituted J558L cells harboring YC3.60 (J558Lμv11 cells) permitted monitoring of Ca(2+) mobilization. Reconstituting CD19 in J558Lμv11 cells resulted in detectable BCR-induced Ca(2+) mobilization but with kinetics different from that of CD45-expressing cells. Furthermore, we evaluated the validity of the J558L system by proteomic analysis of tyrosine-phosphorylated proteins after antigen stimulation. Identification of more than 100 BCR-induced tyrosine-phosphorylated proteins in J558Lμv11 cells revealed a similarity to that observed in B cells, and a novel member, non-receptor protein tyrosine kinase Fer, was found. Thus, this reconstruction system using J558L cells appeared to be valid for comprehensively investigating BCR signaling.

The BAR Domain Superfamily Proteins from Subcellular Structures to Human Diseases

Eukaryotic cells have complicated membrane systems. The outermost plasma membrane contains various substructures, such as invaginations and protrusions, which are involved in endocytosis and cell migration. Moreover, the intracellular membrane compartments, such as autophagosomes and endosomes, are essential for cellular viability. The Bin-Amphiphysin-Rvs167 (BAR) domain superfamily proteins are important players in membrane remodeling through their structurally determined membrane binding surfaces. A variety of BAR domain superfamily proteins exist, and each family member appears to be involved in the formation of certain subcellular structures or intracellular membrane compartments. Most of the BAR domain superfamily proteins contain SH3 domains, which bind to the membrane scission molecule, dynamin, as well as the actin regulatory WASP/WAVE proteins and several signal transduction molecules, providing possible links between the membrane and the cytoskeleton or other machineries. In this review, we summarize the current information about each BAR superfamily protein with an SH3 domain(s). The involvement of BAR domain superfamily proteins in various diseases is also discussed.