Cell proliferation and epidermal growth factor signaling in non-small cell lung adenocarcinoma cell lines are dependent on Rin1

Identification of overlay differentially expressed genes in both rats and goats with blast lung injury through comparative transcriptomics

PURPOSE

To identify the potential target genes of blast lung injury (BLI) for the diagnosis and treatment.

METHODS

This is an experimental study. The BLI models in rats and goats were established by conducting a fuel-air explosive power test in an unobstructed environment, which was subsequently validated through hematoxylin-eosin staining. Transcriptome sequencing was performed on lung tissues from both goats and rats. Differentially expressed genes were identified using the criteria of q ≤ 0.05 and |log2 fold change| ≥ 1. Following that, enrichment analyses were conducted for gene ontology and the Kyoto Encyclopedia of Genes and Genomes pathways. The potential target genes were further confirmed through quantitative real-time polymerase chain reaction and enzyme linked immunosorbent assay.

RESULTS

Observations through microscopy unveiled the presence of reddish edema fluid, erythrocytes, and instances of focal or patchy bleeding within the alveolar cavity. Transcriptome sequencing analysis identified a total of 83 differentially expressed genes in both rats and goats. Notably, 49 genes exhibited a consistent expression pattern, with 38 genes displaying up-regulation and 11 genes demonstrating down-regulation. Enrichment analysis highlighted the potential involvement of the interleukin-17 signaling pathway and vascular smooth muscle contraction pathway in the underlying mechanism of BLI. Furthermore, the experimental findings in both goats and rats demonstrated a strong association between BLI and several key genes, including anterior gradient 2, ankyrin repeat domain 65, bactericidal/permeability-increasing fold containing family A member 1, bactericidal/permeability-increasing fold containing family B member 1, and keratin 4, which exhibited up-regulation.

CONCLUSIONS

Anterior gradient 2, ankyrin repeat domain 65, bactericidal/permeability-increasing fold containing family A member 1, bactericidal/permeability-increasing fold containing family B member 1, and keratin 4 hold potential as target genes for the prognosis, diagnosis, and treatment of BLI.

Cutaneous manifestations in Costello syndrome: HRAS p.Gly12Ser affects RIN1-mediated integrin trafficking in immortalized epidermal keratinocytes

Heterozygous germline missense variants in the HRAS gene underlie Costello syndrome (CS). The molecular basis for cutaneous manifestations in CS is largely unknown. We used an immortalized human cell line, HaCaT keratinocytes, stably expressing wild-type or CS-associated (p.Gly12Ser) HRAS and defined RIN1 as quantitatively most prominent, high-affinity effector of active HRAS in these cells. As an exchange factor for RAB5 GTPases, RIN1 is involved in endosomal sorting of cell-adhesion integrins. RIN1-dependent RAB5A activation was strongly increased by HRASGly12Ser, and HRAS-RIN1-ABL1/2 signaling was induced in HRASWT- and HRASGly12Ser-expressing cells. Along with that, HRASGly12Ser expression decreased total integrin levels and enriched β1 integrin in RAB5- and EEA1-positive early endosomes. The intracellular level of active β1 integrin was increased in HRASGly12Ser HaCaT keratinocytes due to impaired recycling, whereas RIN1 disruption raised β1 integrin cell surface distribution. HRASGly12Ser induced co-localization of β1 integrin with SNX17 and RAB7 in early/sorting and late endosomes, respectively. Thus, by retaining β1 integrin in intracellular endosomal compartments, HRAS-RIN1 signaling affects the subcellular availability of β1 integrin. This may interfere with integrin-dependent processes as we detected for HRASGly12Ser cells spreading on fibronectin. We conclude that dysregulation of receptor trafficking and integrin-dependent processes such as cell adhesion are relevant in the pathobiology of CS.

Novel Resistance Mechanisms to Osimertinib Analysed by Whole-Exome Sequencing in Non-Small Cell Lung Cancer

Purpose

Molecular-based targeted therapy has improved life expectancy for advanced non-small cell lung cancer (NSCLC). However, it does not have to be inevitable that patients receiving third-generation EGFR-TKIs become drug resistant. EGFR C797S and MET amplification are common mechanisms of osimertinib. However, a large part of these potential drug mechanisms remains unknown, and further research is needed.

Methods

Tumour and blood samples from forty advanced NSCLC patients were identified as acquired drug resistant to osimertinib. The NGS panel was applied to detect EGFR C797S and MET amplification in tumour tissues or plasma samples. Whole-exome sequencing was conducted in five pairs of tumour tissues obtained before osimertinib administration and after osimertinib resistance in patients without C797S/cMET amplification.

Results

The overall C797S mutation rate was 20%, and MET amplification was detected in six out of sixteen C797S-negative samples. PDGFRA in the PI3K-AKT-mTOR signalling pathway, RASAL2, RIN3 and SOS2 in the RAS-Raf-ERK signalling pathway, PTK2 in the ERBB signalling pathway and ABCC1 and ABCB5 in the ABC membrane pump system were identified as candidate crucial genes of drug resistance to osimertinib.

Conclusion

EGFR C797S mutation and MET amplification are leading mechanisms for osimertinib resistance in lung cancer. The crucial potential mutated genes defined in our present study may need further validation in a considerable number of lung cancer patients.

Cancer-driving mutations and variants of components of the membrane trafficking core machinery

The core machinery for vesicular membrane trafficking broadly comprises of coat proteins, RABs, tethering complexes and SNAREs. As cellular membrane traffic modulates key processes of mitogenic signaling, cell migration, cell death and autophagy, its dysregulation could potentially results in increased cell proliferation and survival, or enhanced migration and invasion. Changes in the levels of some components of the core machinery of vesicular membrane trafficking, likely due to gene amplifications and/or alterations in epigenetic factors (such as DNA methylation and micro RNA) have been extensively associated with human cancers. Here, we provide an overview of association of membrane trafficking with cancer, with a focus on mutations and variants of coat proteins, RABs, tethering complex components and SNAREs that have been uncovered in human cancer cells/tissues. The major cellular and molecular cancer-driving or suppression mechanisms associated with these components of the core membrane trafficking machinery shall be discussed.

Promoter DNA methylation analysis reveals a novel diagnostic CpG-based biomarker and RAB25 hypermethylation in clear cell renel cell carcinoma

Clear-cell renal cell carcinoma (ccRCC) is a common aggressive urinary malignant tumor that cannot be easily diagnosed at an early stage. The DNA methylation occurs within promoter before precancerous lesion plays a pivotal role that could help us in diagnosing and understanding ccRCC. In this study, based on a whole-genome promoter DNA methylation profiling, we used shrunken centroids classifier method to identify a CpG-based biomarker that is capable of differentiating between ccRCC tumor and adjacent tissues. The biomarker was validated in 19 ccRCCs and three public datasets. We found that both CYP4B1 and RAB25 are downregulated with promoter hypermethylation and CA9 is upregulated with promoter hypomethylation, and we validated their mRNA differential expressions in 19 ccRCCs and 10 GEO datasets. We further confirmed that hypermethylated RAB25 is inversely correlated with its mRNA level. Log-rank test showed that ccRCC patients with low levels of CA9 promoter methylation had a higher survival rate. This reveals clinically a potential biomarker for use in early detection for ccRCC, and provides a better understanding of carcinogenesis.

CMTM7 knockdown increases tumorigenicity of human non-small cell lung cancer cells and EGFR-AKT signaling by reducing Rab5 activation

The dysregulation of epidermal growth factor receptor (EGFR) signaling has been well documented to contribute to the progression of non-small cell lung cancer (NSCLC), the leading cause of cancer death in the world. EGF-stimulated EGFR activation induces receptor internalization and degradation, which plays an important role in EGFR signaling. This process is frequently deregulated in cancer cells, leading to enhanced EGFR levels and signaling. Our previous study on CMTM7 is only limited to a brief description of the relationship of overexpressed CMTM7 with EGFR-AKT signaling. The biological functions of endogenous CMTM7 and its molecular mechanism remained unclear. In this study, we show that the stable knockdown of CMTM7 augments the malignant potential of NSCLC cells and enhances EGFR-AKT signaling by decreasing EGFR internalization and degradation. Mechanistically, CMTM7 knockdown reduces the activation of Rab5, a protein known to be required for early endosome fusion. In NSCLC, the loss of CMTM7 would therefore serve to sustain aberrant EGFR-mediated oncogenic signaling. Together, our findings highlight the role of CMTM7 in the regulation of EGFR signaling in tumor cells, revealing CMTM7 as a novel molecule related to Rab5 activation.

Progesterone receptor (PR) polyproline domain (PPD) mediates inhibition of epidermal growth factor receptor (EGFR) signaling in non-small cell lung cancer cells

Recent evidence has suggested a possible role for progesterone receptor (PR) in the progression of non-small cell lung cancer (NSCLC). However, little is known concerning roles of PR in NSCLC. PR contains a polyproline domain (PPD), which directly binds to the SH3 domain of signaling molecules. Because PPD-SH3 interactions are essential for EGFR signaling, we hypothesized that the presence of PR-PPD interfered with EGFR-mediated signaling and cell proliferation. We examined the role of PR-PPD in cell proliferation and signaling by stably expressing PR-B, or PR-B with disrupting mutations in the PPD (PR-BΔSH3), from a tetracycline-regulated promoter in A549 NSCLC cells. PR-B dose-dependently inhibited cell growth in the absence of ligand, and progestin (R5020) treatment further suppressed the growth. Treatment with RU486 abolished PR-B- and R5020-mediated inhibition of cell proliferation. Expression of PR-BΔSH3 and treatment with R5020 or RU486 had no effect on cell proliferation. Furthermore, PR-B expression but not PR-BΔSH3 expression reduced EGF-induced A549 proliferation and activation of ERK1/2, in the absence of ligand. Taken together, our data demonstrated the significance of PR extranuclear signaling through PPD interactions in EGFR-mediated proliferation and signaling in NSCLC.

Laricitrin suppresses increased benzo(a)pyrene-induced lung tumor-associated monocyte-derived dendritic cell cancer progression

Benzo(a)pyrene (BaP) stimulates lung cancer cells, promoting monocyte-derived dendritic cells to secrete soluble factors, including heparin binding-epidermal growth factor and C-X-C motif chemokine 5. The secretions from monocyte-derived dendritic cells stimulate the progression of lung cancer cells, including the migration and invasion of cells. To the best of our knowledge, these secretions remain unknown, and require additional study. The present study identified that treatment with BaP-H1395-tumor-associated dendritic cell-conditioned medium had the most marked effect on cell migration and invasion. This result may be associated with the female gender, stage 2 adenocarcinoma or mutation of the proto-oncogene B-Raf (BRAF), according to the cell line background. Laricitrin, a dietary flavonoid derivative present in grapes and red wine, suppresses certain factors and decreases the progression of lung cancer cells that are promoted by BaP in the lung cancer tumor microenvironment. The results of the present study suggest that prolonged exposure to BaP exacerbates lung cancer, particularly in female lung cancer patients with the BRAF mutation, but that laricitrin may ameliorate this effect.

Production of human epidermal growth factor using adenoviral based system

Epidermal growth factor (EGF), a growth factor involved in cell growth and differentiation, is a small polypeptide with molecular weight of approximately 6 kDa known to be present in a number of different mammalian species. Experimental studies in animals and humans have demonstrated that the topical application of EGF accelerates the rate of epidermal regeneration of partial-thickness wounds and second-degree burns. Due to its commercial applications, Human EGF (hEGF) has been cloned in several forms. In the present study, adenoviral based expression system was used to produce biologically active recombinant hEGF. The presence of secreted recombinant hEGF was confirmed by a dot blot and its expression level was determined by enzyme-linked immuno-sorbent assay. Moreover, biological activity of secreted hEGF was evaluated by a proliferation assay performed on A549 cells. For production of hEGF in a secretory form, a chimeric gene coding for the hEGF fused to the signal peptide was expressed using adenoviral based method. This method enables the production of hEGF at the site of interest and moreover it could be used for cell proliferation and differentiation assays in tissue engineering research experiments instead of using commercially available EGF.

Detection of Novel Genomic Markers for Predicting Prognosis in Hepatocellular Carcinoma Patients by Integrative Analysis of Copy Number Aberrations and Gene Expression Profiles: Results from a Long-Term Follow-Up

The aim of this study was to explore novel genomic biomarkers predicting hepatocellular carcinoma (HCC) prognosis by integrative analysis of DNA copy number aberrations (CNAs) and gene expression profiles. Array comparative genomic hybridization and expression array were performed on 45 and 31 HCC samples, respectively. To identify functionally important genes, concordant results of DNA copy number and gene expression were retrieved by integrative analysis. Cox regression analysis indicated that the CNAs in 192 genomic regions were significantly associated with overall survival (OS; p < 0.05). Integrative analysis capturing concordant results demonstrated that the low expression of TLE4 (p = 0.041) and XPA (p = 0.006) was associated with poor OS. In the analysis of tumor recurrence, 514 genomic regions with CNAs were associated with recurrence. Integrative analysis revealed that the overexpression of 16 genes, including FGR (p = 0.003), RELA (p = 0.049), LTBP3 (p = 0.050), and RIN1 (p = 0.023), was significantly associated with shorter time to tumor recurrence. On multivariate analysis, FGR and XPA were independent risk factors of early recurrence and poor OS, respectively. Integrated analysis of CNAs and gene expression profiles correlated with long-term follow-up data successfully identified potential prognostic markers predicting survival and tumor recurrence in patients with HCC who underwent surgical resection.

Tyrosine phosphorylation of RAS by ABL allosterically enhances effector binding

RAS proteins are signal transduction gatekeepers that mediate cell growth, survival, and differentiation through interactions with multiple effector proteins. The RAS effector RAS- and RAB-interacting protein 1 (RIN1) activates its own downstream effectors, the small GTPase RAB5 and the tyrosine kinase Abelson tyrosine-protein kinase (ABL), to modulate endocytosis and cytoskeleton remodeling. To identify ABL substrates downstream of RAS-to-RIN1 signaling, we examined human HEK293T cells overexpressing components of this pathway. Proteomic analysis revealed several novel phosphotyrosine peptides, including Harvey rat sarcoma oncogene (HRAS)-pTyr(137). Here we report that ABL phosphorylates tyrosine 137 of H-, K-, and NRAS. Increased RIN1 levels enhanced HRAS-Tyr(137) phosphorylation by nearly 5-fold, suggesting that RAS-stimulated RIN1 can drive ABL-mediated RAS modification in a feedback circuit. Tyr(137) is well conserved among RAS orthologs and is part of a transprotein H-bond network. Crystal structures of HRAS(Y137F) and HRAS(Y137E) revealed conformation changes radiating from the mutated residue. Although consistent with Tyr(137) participation in allosteric control of HRAS function, the mutations did not alter intrinsic GTP hydrolysis rates in vitro. HRAS-Tyr(137) phosphorylation enhanced HRAS signaling capacity in cells, however, as reflected by a 4-fold increase in the association of phosphorylated HRAS(G12V) with its effector protein RAF proto-oncogene serine/threonine protein kinase 1 (RAF1). These data suggest that RAS phosphorylation at Tyr(137) allosterically alters protein conformation and effector binding, providing a mechanism for effector-initiated modulation of RAS signaling.

Hypomethylated Rab27b is a progression-associated prognostic biomarker of glioma regulating MMP-9 to promote invasion

In the present study, in order to analyze abnormalities in DNA methylation in glioma, we utilized a large cohort methylation microarray (119 glioma samples). Genes associated with tumor grade progression were screened through Significance Analysis of Microarrays (SAM) in the methylation microarray. We found that Rab27b was hypomethylated in high-grade glioma (anaplastic gliomas and glioblastomas) compared with low-grade glioma (astrocytoma, oligodendrocytoma and oligoastrocytoma) (p=0.02). In 52 glioma samples, we determined both the methylation status of the Rab27b promoter region and protein expression, and confirmed a negative correlation between the methylation status and expression (p<0.01). Immunohistochemistry of 91 gliomas revealed that the Rab27b expression scores of high-grade glioma were higher than scores of low-grade gliomas (p<0.01). In high‑grade gliomas, patients haboring Rab27b hypomethylation or overexpression had unfavorable survival prognosis. Transwell invasion assays identified that invasive cell number of glioma U87 and LN229 cells decreased when Rab27b was knocked down. Decreased invasion partly resulted from reduced expression and activation of MMP-9 after Rab27b knockdown. Downregulation of Rab27b also suppressed tumor growth in vivo. Hypomethylated Rab27b was identified as a progression-associated and prognostic molecular marker of glioma.

Role of Rab GTPases and their interacting proteins in mediating metabolic signalling and regulation

The vesicular transport pathways, which shuttle materials to and from the cell surface and within the cell, and the metabolic (growth factor and nutrient) signalling pathways, which integrate a variety of extracellular and intracellular signals to mediate growth, proliferation or survival, are both important for cellular physiology. There is evidence to suggest that the transport and metabolic signalling pathways intersect-vesicular transport can affect the regulation of metabolic signals and vice versa. The Rab family GTPases regulate the specificity of vesicular transport steps in the cell. Together with their interacting proteins, Rabs would likely constitute the points of intersection between vesicular transport and metabolic signalling pathways. Examples of these points would include growth factor signalling, glucose and lipid metabolism, as well as autophagy. Many of these processes involve mechanistic/mammalian target of rapamycin (mTOR) complex 1 (mTORC1) in downstream cascades, or are regulated by TORC signalling. A general functionality of the vesicular transport processes controlled by the Rabs is also important for spatial and temporal regulation of the transmission of metabolic signals between the cell surface and the nucleus. In other cases, specific Rabs and their interacting proteins are known to function in recruiting metabolism-related proteins to target membranes, or may compete with other factors in the TORC signalling pathway as a means of metabolic regulation. We review and discuss herein examples of how Rabs and their interacting proteins can mediate metabolic signalling and regulation in cells.

Preferential accumulation of the near infrared heptamethine dye IR-780 in the mitochondria of drug-resistant lung cancer cells

Personalized oncology significantly relies on the development of theranostic agents to integrate cancer therapeutics and diagnostics. Current strategy for development of such multifunctional agents requires multistep chemical conjugation with cancer specific ligands, contrast agents and therapeutic drugs. In this study, we reported a near infrared (NIR) heptamethine indocyanine dye, IR-780, which selectively accumulated in the mitochondria of drug-resistant human lung cancer cells (A549/DR) and significantly inhibited cell growth, self-renewal and migration without the need of any chemical conjugation. IR-780 was also able to induce A549/DR cell apoptosis by disrupting the mitochondrial function. Furthermore, IR-780 dye exhibited remarkable tumoricidal activity and inhibited tumor recurrence in mouse syngeneic Lewis lung carcinoma xenograft model. With the unique properties of targeting, near infrared imaging and inhibitive effect to the drug-resistant cancer cells both in vitro and in vivo, IR-780 may represent a potential theranostic agent for tumor recurrence.

Endocytosis and cancer

Endocytosis entails selective packaging of cell-surface proteins, such as receptors for cytokines and adhesion components, in cytoplasmic vesicles (endosomes). The series of sorting events that determines the fate of internalized proteins, either degradation in lysosomes or recycling back to the plasma membrane, relies on intrinsic sequence motifs, posttranslational modifications (e.g., phosphorylation and ubiquitination), and transient assemblies of both Rab GTPases and phosphoinositide-binding proteins. This multicomponent process is enhanced and skewed in cancer cells; we review mechanisms enabling both major drivers of cancer, p53 and Ras, to bias recycling of integrins and receptor tyrosine kinases (RTKs). Likewise, cadherins and other junctional proteins of cancer cells are constantly removed from the cell surface, thereby disrupting tissue polarity and instigating motile phenotypes. Mutant forms of RTKs able to evade Cbl-mediated ubiquitination, along with overexpression of the wild-type forms and a variety of defective feedback regulatory loops, are frequently detected in tumors. Finally, we describe pharmacological attempts to harness the peculiar endocytic system of cancer, in favor of effective patient treatment.

Genomic profiles and CRTC1-MAML2 fusion distinguish different subtypes of mucoepidermoid carcinoma

Mucoepidermoid carcinoma is the most common salivary gland malignancy, and includes a spectrum of lesions ranging from non-aggressive low-grade tumors to aggressive high-grade tumors. To further characterize this heterogeneous group of tumors we have performed a comprehensive analysis of copy number alterations and CRTC1-MAML2 fusion status in a series of 28 mucoepidermoid carcinomas. The CRTC1-MAML2 fusion was detected by RT-PCR or fluorescence in situ hybridization in 18 of 28 mucoepidermoid carcinomas (64%). All 15 low-grade tumors were fusion-positive whereas only 3 of 13 high-grade tumors were fusion-positive. High-resolution array-based comparative genomic hybridization revealed that fusion-positive tumors had significantly fewer copy number alterations/tumor compared with fusion-negative tumors (1.5 vs 9.5; P=0.002). Twelve of 18 fusion-positive tumors had normal genomic profiles whereas only 1 out of 10 fusion-negative tumors lacked copy number alterations. The profiles of fusion-positive and fusion-negative tumors were very similar to those of low- and high-grade tumors. Thus, low-grade mucoepidermoid carcinomas had significantly fewer copy number alterations/tumor compared with high-grade mucoepidermoid carcinomas (0.7 vs 8.6; P<0.0001). The most frequent copy number alterations detected were losses of 18q12.2-qter (including the tumor suppressor genes DCC, SMAD4, and GALR1), 9p21.3 (including the tumor suppressor genes CDKN2A/B), 6q22.1-q23.1, and 8pter-p12.1, and gains of 8q24.3 (including the oncogene MAFA), 11q12.3-q13.2, 3q26.1-q28, 19p13.2-p13.11, and 8q11.1-q12.2 (including the oncogenes LYN, MOS, and PLAG1). On the basis of these results we propose that mucoepidermoid carcinoma may be subdivided in (i) low-grade, fusion-positive mucoepidermoid carcinomas with no or few genomic imbalances and favorable prognosis, (ii) high-grade, fusion-positive mucoepidermoid carcinomas with multiple genomic imbalances and unfavorable prognosis, and (iii) a heterogeneous group of high-grade, fusion-negative adenocarcinomas with multiple genomic imbalances and unfavorable outcome. Taken together, our studies indicate that molecular genetic analysis can be a useful adjunct to histologic scoring of mucoepidermoid carcinoma and may lead to development of new clinical guidelines for management of these patients.

RIN3 is a negative regulator of mast cell responses to SCF

Stimulation of the receptor tyrosine kinase KIT by Stem Cell Factor (SCF) triggers activation of RAS and its downstream effectors. Proper KIT activation is essential for the maturation, survival and proliferation of mast cells. In addition, SCF activation of KIT is critical for recruiting mast cells to sites of infection or injury, where they release a mix of pro-inflammatory substances. RIN3, a RAS effector and RAB5-directed guanine nucleotide exchange factor (GEF), is highly expressed and enriched in human mast cells. SCF treatment of mast cells increased the amount of GTP-bound RAB5, and the degree of RAB5 activation correlated with the expression level of RIN3. At the same time, SCF caused the dissociation of a pre-formed complex of RIN3 with BIN2, a membrane bending protein implicated in endocytosis. Silencing of RIN3 increased the rate of SCF-induced KIT internalization, while persistent RIN3 over-expression led to KIT down regulation. These observations strongly support a role for RIN3 in coordinating the early steps of KIT endocytosis. Importantly, RIN3 also functioned as an inhibitor of mast cell migration toward SCF. Finally, we demonstrate that elevated RIN3 levels sensitize mastocytosis cells to treatment with a KIT tyrosine kinase inhibitor, suggesting the value of a two-pronged inhibitor approach for this difficult to treat malignancy. These findings directly connect KIT activation with a mast cell-specific RAS effector that regulates the cellular response to SCF and provide new insight for the development of more effective mastocytosis treatments.

Prognostic significance of RIN1 gene expression in human non-small cell lung cancer

Ras interaction/interference 1 (RIN1), originally identified as a Ras effector protein, has been implicated in tumorigenesis and development of human cancers. The aim of this study was to detect RIN1 expression in human non-small cell lung cancer (NSCLC) and to analyze its association with prognosis of NSCLC patients. Quantitative real-time RT-PCR was performed to examine the expression of RIN1 mRNA in 25 cases of NSCLC and corresponding non-tumor tissue samples. Immunohistochemistry was performed to detect the expression of RIN1 in 90 NSCLC tissues. We found that the expression levels of RIN1 mRNA in NSCLC tissues were significantly higher than those in corresponding non-tumor tissues. High-level RIN1 expression was observed in 53.3% (48 of 90 cases), and correlated with poor tumor differentiation (P=0.024), TNM stage (P=0.032), and lymph node metastasis (P=0.018). Patients with high expression levels of RIN1 showed lower overall survival rate than those with low expression levels (P=0.033). Multivariate analysis showed that high RIN1 protein expression was an independent prognostic factor for NSCLC patients (P=0.021). Our study suggests that over-expression of RIN1 may play an important role in the progression of NSCLC and RIN1 expression may offer a valuable marker for predicting the outcome of patients with NSCLC.

Eosinophil crystalloid granules: structure, function, and beyond

Eosinophils are granulocytes associated with host defense against parasitic helminths with allergic conditions and more recently, with immunoregulatory responses. Eosinophils are distinguished from leukocytes by their dominant population of cytoplasmic crystalloid (also termed secretory, specific, or secondary) granules that contain robust stores of diverse, preformed cationic proteins. Here, we provide an update on our knowledge about the unique and complex structure of human eosinophil crystalloid granules. We discuss their significance as rich sites of a variety of receptors and review our own recent research findings and those of others that highlight discoveries concerning the function of intracellular receptors and their potential implications in cell signaling. Special focus is provided on how eosinophils might use these intracellular receptors as mechanisms to secrete, selectively and rapidly, cytokines or chemokines and enable cell-free extracellular eosinophil granules to function as independent secretory structures. Potential roles of cell-free eosinophil granules as immune players in the absence of intact eosinophils will also be discussed.

RIN1 exhibits oncogenic property to suppress apoptosis and its aberrant accumulation associates with poor prognosis in melanoma

Malignant melanoma is an increasing disease in China, and its molecular mechanisms of development and progression are limited. The objective of this study was to investigate the expression of Ras interaction/interference 1 (RIN1) protein and its clinical significance in human melanoma. Immunohistochemistry was performed to detect the expression of RIN1 in 81 melanoma patients with a 5-year follow-up. The prognosis of the patients, classified by the clinicopathologic features and RIN1 expression, was assessed by multivariate analysis. RIN1 levels were then analyzed with overall survival (OS), progression-free survival (PFS), and recurrence-free survival (RFS) in the cohort. The biological function was determined by proliferation assay, flow cytometry analysis through knocking down of RIN1 in melanoma cells A375, as well as caspase-3 activation and PARP cleavage were detected by western blot or fluorometric assay. Data showed that RIN1 was overexpressed in melanoma samples. High-level RIN1 expression was observed in 49.4 % (40 of 81 cases), associated with thickness grade (P = 0.008) and lymph node metastasis (P < 0.001). Two distinguished subgroups were segregated by RIN1 levels within this set comparing prognostication of OS, PFS, and RFS. Importantly, RIN1 level was revealed as the significant independent prognostic factor for death and progression but a weak contribution for recurrence. Moreover, knock down of RIN1 expression in A375 cells, suppressed cell proliferation and induced apoptosis through caspase-3 activation and PARP cleavage. RIN1 expression could be a potential prognostic predictor for the melanoma patients and provide a potential target therapy for melanoma treatment.

High RIN1 expression is associated with poor prognosis in patients with gastric adenocarcinoma

The aim of this study was to investigate the expression and prognostic significance of RIN1 in gastric adenocarcinoma. RIN1 expression was analyzed using quantitative real-time PCR (qRT-PCR), Western blotting, and immunohistochemical staining on tissue samples from a consecutive series of 315 gastric adenocarcinoma patients who underwent tumor resections between 2003 and 2006. The relationship between RIN1 expression, clinicopathological factors, and patient survival was investigated. qRT-PCR results showed that the RIN1 mRNA expression was higher in tumor tissue samples than in the adjacent normal tissues, and a corresponding increase in protein expression was confirmed by Western blotting. Immunohistochemical staining indicated that RIN1 is highly expressed in 54.3 % of gastric adenocarcinomas. RIN1 expression levels were closely associated with tumor size, histological differentiation, tumor stage, and lymph node involvement. Kaplan-Meier survival analysis showed that high RIN1 expression exhibited a significant correlation with poor prognosis for gastric adenocarcinoma patients. Multivariate analysis revealed that RIN1 expression is an independent prognostic parameter for the overall survival rate of gastric adenocarcinoma patients. Our data suggest that RIN1 plays an important role in gastric adenocarcinoma progression and that a high RIN1 expression predicts an unfavorable prognosis in gastric adenocarcinoma patients.

High RIN1 expression is associated with poor prognosis in patients with gastric adenocarcinoma

The aim of this study was to investigate the expression and prognostic significance of RIN1 in gastric adenocarcinoma. RIN1 expression was analyzed using quantitative real-time PCR (qRT-PCR), Western blotting, and immunohistochemical staining on tissue samples from a consecutive series of 315 gastric adenocarcinoma patients who underwent tumor resections between 2003 and 2006. The relationship between RIN1 expression, clinicopathological factors, and patient survival was investigated. qRT-PCR results showed that the RIN1 mRNA expression was higher in tumor tissue samples than in the adjacent normal tissues, and a corresponding increase in protein expression was confirmed by Western blotting. Immunohistochemical staining indicated that RIN1 is highly expressed in 54.3 % of gastric adenocarcinomas. RIN1 expression levels were closely associated with tumor size, histological differentiation, tumor stage, and lymph node involvement. Kaplan-Meier survival analysis showed that high RIN1 expression exhibited a significant correlation with poor prognosis for gastric adenocarcinoma patients. Multivariate analysis revealed that RIN1 expression is an independent prognostic parameter for the overall survival rate of gastric adenocarcinoma patients. Our data suggest that RIN1 plays an important role in gastric adenocarcinoma progression and that a high RIN1 expression predicts an unfavorable prognosis in gastric adenocarcinoma patients.

Overexpression of RIN1 associates with tumor grade and progression in patients of bladder urothelial carcinoma

Ras and Rab interactor 1 (RIN1) is an effector of H-Ras, which plays an important role in the development and progression of carcinomas, but it has not been reported in bladder cancer. Hence, the association of RIN1 expression with prognosis of bladder urothelial carcinoma (UC) was examined. RIN1 mRNA and protein expression in 20 paired UCs and the adjacent normal tissues was detected by quantitative reverse transcription polymerase chain reaction and Western blot. The expression of RIN1 protein in 96 specimens of UCs and 22 specimens of adjacent normal bladder tissues were analyzed by immunohistochemistry. The overall survival (OS) was assessed by univariate and multivariate analysis. Moreover, the progression-free survival (PFS) and recurrence-free survival (RFS), classified by the clinicopathologic features with RIN1 expression, were assessed by multivariate analysis. RIN1 mRNA and protein level was higher in UCs than in the adjacent normal tissues (P < 0.01). Enhanced RIN1 immunoexpression was associated with high histologic grades (P = 0.046), cancer progression (P = 0.047) as well as Ki-67 expression (P = 0.023). Furthermore, the 5-year survival rate was 29% in the subgroup with high level of RIN1 expression, while it was 43% in the subgroup with normal level of RIN1 expression (P < 0.05). Importantly, RIN1 level was revealed as the significant independent prognostic factor for death (P = 0.023) and progression (P = 0.003), but a weak contribution for recurrence (P = 0.063). Collectively, RIN1 expression could be a potential prognostic predictor for UC patients.

c-Jun N-terminal kinase 2 (JNK2) enhances cell migration through epidermal growth factor substrate 8 (EPS8)

Membrane-bound receptors induce biochemical signals to remodel the actin cytoskeleton and mediate cell motility. In association with receptor tyrosine kinases, several downstream mitogen-induced kinases facilitate cell migration. Here, we show a role for c-Jun N-terminal kinase 2 (JNK2) in promoting mammary cancer cell migration through inhibition of epidermal growth factor substrate 8 (EPS8) expression, a key regulator of EGF receptor (R) signaling and trafficking. Using jnk2(-/-) mice, we found that EPS8 expression is higher in polyoma middle T antigen (PyVMT)jnk2(-/-) mammary tumors and jnk2(-/-) mammary glands compared with the respective jnk2(+/+) controls. The inverse relationship between the jnk2 and eps8 expression was also associated with cancer progression in that patients with basal-type breast tumors expressing high jnk2 and low eps8 experienced poor disease-free survival. In mammary tumor cell lines, the absence of jnk2 greatly reduces cell migration that is rescued by EPS8 knockdown. Subsequent studies show that JNK2 enhances formation of the EPS8-Abi-1-Sos-1 complex to augment EGFR activation of Akt and ERK, whereas the absence of JNK2 promotes ESP8/RN-Tre association to inhibit endocytotic trafficking of the EGFR. Together, these studies unveil a critical role for JNK2 and EPS8 in receptor tyrosine kinase signaling and trafficking to convey distinctly different effects on cell migration.

Integrin-mediated function of Rab GTPases in cancer progression

The RAS (rat sarcoma) superfamily of small GTPases is broadly subdivided into five groups: Ras, Rho, Rab, Ran, and Arf. Rab family proteins are important in regulating signal transduction and cellular processes such as differentiation, proliferation, vesicle transport, nuclear assembly, and cytoskeleton formation. However, some Rab proteins have been reported to be necessary for the adhesion and migration of cancer cells. Although Ras and Rho family members have been strongly implicated in cancer progression, knowledge of Rabs action in this regard is limited. Some reports have also linked Rab GTPases with cancer cell migration and invasiveness. This review discusses the implications of the involvement of Rabs in malignant transformation and cancer therapy through integrin-mediated signaling events, with particular emphasis on breast cancer.

ABL fusion oncogene transformation and inhibitor sensitivity are mediated by the cellular regulator RIN1

ABL gene translocations create constitutively active tyrosine kinases that are causative in chronic myeloid leukemia, acute lymphocytic leukemia and other hematopoietic malignancies. Consistent retention of ABL SH3/SH2 autoinhibitory domains, however, suggests that these leukemogenic tyrosine kinase fusion proteins remain subject to regulation. We resolve this paradox, demonstrating that BCR-ABL1 kinase activity is regulated by RIN1, an ABL SH3/SH2 binding protein. BCR-ABL1 activity was increased by RIN1 overexpression and decreased by RIN1 silencing. Moreover, Rin1(-/-) bone marrow cells were not transformed by BCR-ABL1, ETV6-ABL1 or BCR-ABL1(T315I), a patient-derived drug-resistant mutant, as judged by growth factor independence. Rescue by ectopic RIN1 verified a cell autonomous mechanism of collaboration with BCR-ABL1 during transformation. Sensitivity to the ABL kinase inhibitor imatinib was increased by RIN1 silencing, consistent with RIN1 stabilization of an activated BCR-ABL1 conformation having reduced drug affinity. The dependence on activation by RIN1 to unleash full catalytic and cell transformation potential reveals a previously unknown vulnerability that could be exploited for treatment of leukemic cases driven by ABL translocations. The findings suggest that RIN1 targeting could be efficacious for imatinib-resistant disease and might complement ABL kinase inhibitors in first-line therapy.

Signaling by internalized G-protein-coupled receptors

G-protein-coupled receptors (GPCRs) are cell surface receptors and are generally assumed to signal to second messengers such as cyclic AMP (cAMP) exclusively from the plasma membrane. However, recent studies indicate that GPCRs can continue signaling to cAMP after internalization together with their agonists. Signaling from inside the cell is persistent and appears to trigger specific downstream effects. Here, we will review these recent data, which form the basis for a novel concept of intracellular GPCR signaling and suggest new and intriguing scenarios for the functions of GPCRs in the endocytic compartment. We propose that current models of GPCR signaling should be revised to accommodate the ability of receptors to change their signaling properties depending on their subcellular localization.