CEA-Ki-67- Pathologic Subtype: An Adjunct Factor for Refining Prognosis in Stage I Pulmonary Adenocarcinoma.

Objectives: The prognosis for stage I pulmonary adenocarcinoma is generally good. However, some patients with stage I pulmonary adenocarcinoma have an unexpectedly poor outcome. This warrants consideration of adjunct markers. In this study, we analyze carcinoembryonic antigen, Ki-67, and a pathologic subtype in combination for prognostic evaluation of stage I pulmonary adenocarcinoma. These factors were selected for study as they have been shown to be individually associated with prognosis in many studies. Methods: A total of 650 patients with stage I pulmonary adenocarcinoma were investigated retrospectively. Each patient was re-staged using standard TNM criteria. Carcinoembryonic antigen (CEA) values were obtained from preoperative blood samples, and Ki-67 was evaluated with tumor tissue immunohistochemistry. Patient clinicopathologic characteristics, survival status, and date of death were obtained from medical records and telephone follow-up. Results: CEA > 4.4 ng/ml, Ki-67 > 13%, and a solid-micropapillary tumor growth pattern were each independent adverse prognostic markers for 5-year disease specific survival in stage I pulmonary adenocarcinoma. However, in combination, these 3 factors yielded a prognostic value (designated "CEA-Ki-67-pathologic subtype" value). Stage I pulmonary adenocarcinoma of low-risk CEA-Ki-67-pathologic subtype (CKP) value show biologic behavior similar to TNM stage IA1 tumors, while stage I tumors of high-risk CKP value are similar in prognosis to TNM stage II. Conclusion: The CKP value may be used as an adjunct to the TNM classification, which may yield a more accurately defined prognosis for cases of stage I pulmonary adenocarcinoma. CKP value may identify patients at higher risk who may benefit from adjuvant chemotherapy. Conversely, lower risk CKP values may support avoidance of chemotherapy.

The phosphatase PAC1 acts as a T cell suppressor and attenuates host antitumor immunity.

Cancer cells subvert immune surveillance through inhibition of T cell effector function. Elucidation of the mechanism of T cell dysfunction is therefore central to cancer immunotherapy. Here, we report that dual specificity phosphatase 2 (DUSP2; also known as phosphatase of activated cells 1, PAC1) acts as an immune checkpoint in T cell antitumor immunity. PAC1 is selectively upregulated in exhausted tumor-infiltrating lymphocytes and is associated with poor prognosis of patients with cancer. PAC1hi effector T cells lose their proliferative and effector capacities and convert into exhausted T cells. Deletion of PAC1 enhances immune responses and reduces cancer susceptibility in mice. Through activation of EGR1, excessive reactive oxygen species in the tumor microenvironment induce expression of PAC1, which recruits the Mi-2ß nucleosome-remodeling and histone-deacetylase complex, eventually leading to chromatin remodeling of effector T cells. Our study demonstrates that PAC1 is an epigenetic immune regulator and highlights the importance of targeting PAC1 in cancer immunotherapy.

PTENα regulates endocytosis and modulates olfactory function.

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) α is the first identified isoform of the well-known tumor suppressor PTEN. PTENα has an evolutionarily conserved 173-aa N terminus compared with canonical PTEN. Recently, PTENα has been shown to play roles in multiple biologic processes including learning and memory, cardiac homeostasis, and antiviral immunity. Here, we report that PTENα maintains mitral cells in olfactory bulb (OB), regulates endocytosis in OB neurons, and controls olfactory behaviors in mice. We show that PTENα directly dephosphorylates the endocytic protein amphiphysin and promotes its binding to adaptor-related protein complex 2 subunit ß1 (Ap2b1). In addition, we identified mutations in the N terminus of PTENα in patients with Parkinson disease and Lewy-body dementia, which are neurodegenerative disorders with early olfactory loss. Overexpression of PTENα mutant H169N in mice OB reduces odor sensitivity. Our data demonstrate a role of PTENα in olfactory function and provide insight into the mechanism of olfactory dysfunction in neurologic disorders.-Yuan, Y., Zhao, X., Wang, P., Mei, F., Zhou, J., Jin, Y., McNutt, M. A., Yin, Y. PTENα regulates endocytosis and modulates olfactory function.

PTEN arginine methylation by PRMT6 suppresses PI3K-AKT signaling and modulates pre-mRNA splicing.

Arginine methylation is a ubiquitous posttranslational modification that regulates critical cellular processes including signal transduction and pre-mRNA splicing. Here, we report that the tumor-suppressor PTEN is methylated by protein arginine methyltransferase 6 (PRMT6). Mass-spectrometry analysis reveals that PTEN is dimethylated at arginine 159 (R159). We found that PTEN is mutated at R159 in cancers, and the PTEN mutant R159K loses its capability to inhibit the PI3K-AKT cascade. Furthermore, PRMT6 is physically associated with PTEN, promotes asymmetrical dimethylation of PTEN, and regulates the PI3K-AKT cascade through PTEN R159 methylation. In addition, using transcriptome analyses, we found that PTEN R159 methylation is involved in modulation of pre-mRNA alternative splicing. Our results demonstrate that PTEN is functionally regulated by arginine methylation. We propose that PTEN arginine methylation modulates pre-mRNA alternative splicing and influences diverse physiologic processes.

PTENα promotes neutrophil chemotaxis through regulation of cell deformability.

Neutrophils are a major component of immune defense and are recruited through neutrophil chemotaxis in response to invading pathogens. However, the molecular mechanism that controls neutrophil chemotaxis remains unclear. Here, we report that PTENα, the first isoform identified in the PTEN family, regulates neutrophil deformability and promotes chemotaxis of neutrophils. A high level of PTENα is detected in neutrophils and lymphoreticular tissues. Homozygous deletion of PTENα impairs chemoattractant-induced migration of neutrophils. We show that PTENα physically interacts with cell membrane cross-linker moesin through its FERM domain and dephosphorylates moesin at Thr558, which disrupts the association of filamentous actin with the plasma membrane and subsequently induces morphologic changes in neutrophil pseudopodia. These results demonstrate that PTENα acts as a phosphatase of moesin and modulates neutrophil-mediated host immune defense. We propose that PTENα signaling is a potential target for the treatment of infections and immune diseases.

Succinylation-dependent mitochondrial translocation of PKM2 promotes cell survival in response to nutritional stress.

Tumor growth and progression is characteristically associated with the synergistic effects of uncontrolled cellular proliferation and cell survival under stress. Pyruvate kinase M2 (PKM2) contributes to both of these effects. However, the specific mechanism by which PKM2 promotes uncontrolled proliferation or cell survival under stress in different nutritional environments is unclear. We show that succinylation mediated mitochondrial translocation of PKM2 under glucose starvation plays a role in switching the cellular machinery from proliferation to cell survival mode and vice versa. Mitochondrial PKM2 inhibits ubiquitination-mediated degradation of voltage-dependent anion channel 3 (VDAC3) and increases mitochondrial permeability to generate more ATP for cell survival under nutritional depletion. We found there is a positive correlation of upregulation of mitochondrial PKM2 and upregulation of VDAC3 in human colon cancer. This shows the mechanisms identified in this study in fact play a role in neoplastic biology. We therefore developed a small molecule designated compound 8 that blocks mitochondrial translocation of PKM2 and inhibits tumor development. Our data suggest that blocking PKM2 mitochondrial function with a small molecule inhibitor has potential for cancer treatment.

Mutations of deubiquitinase OTUD1 are associated with autoimmune disorders.

Dysregulation of innate immunity accompanied by excessive interferon production contributes to autoimmune disease. However, the mechanism by which the immune response is modulated in autoimmune disorders is largely unknown. Here we identified loss-of-function mutations of OTUD1 associated with multiple autoimmune diseases. Under inflammatory conditions, inducible OTUD1 acts as an immune checkpoint and blocks RIG-I-like receptors signaling. As a deubiquitinase, OTUD1 directly interacts with transcription factor IRF3 and removes the K63-linked poly-ubiquitin chains on IRF3 Lysine 98, which inhibits IRF3 nuclear translocation and transcriptional activity. In contrast, OTUD1 mutants impair its suppressive effects on IRF3 via attenuating the OTUD1 deubiquinase activity or its association with IRF3. Moreover, we found FOXO3 signaling is required for OTUD1 induction upon antigenic stimulation. Our data demonstrate that OTUD1 is involved in maintaining immune homeostasis and loss-of-function mutations of OTUD1 enhance the immune response and are associated with autoimmunity.

PTENα regulates mitophagy and maintains mitochondrial quality control.

PTEN plays an important role in tumor suppression, and PTEN family members are involved in multiple biological processes in various subcellular locations. Here we report that PTENα, the first identified PTEN isoform, regulates mitophagy through promotion of PARK2 recruitment to damaged mitochondria. We show that PTENα-deficient mice exhibit accumulation of cardiac mitochondria with structural and functional abnormalities, and PTENα-deficient mouse hearts are more susceptible to injury induced by isoprenaline and ischemia-reperfusion. Mitochondrial clearance by mitophagy is also impaired in PTENα-deficient cardiomyocytes. In addition, we found PTENα physically interacts with the E3 ubiquitin ligase PRKN, which is an important mediator of mitophagy. PTENα binds PRKN through the membrane binding helix in its N-terminus, and promotes PRKN mitochondrial translocation through enhancing PRKN self-association in a phosphatase-independent manner. Loss of PTENα compromises mitochondrial translocation of PRKN and resultant mitophagy following mitochondrial depolarization. We propose that PTENα functions as a mitochondrial quality controller that maintains mitochondrial function and cardiac homeostasis. ABBREVIATIONS: BECN1 beclin 1; CCCP carbonyl cyanide m-chlorophenylhydrazone; FBXO7 F-box protein 7; FS fraction shortening; HSPA1L heat shock protein family A (Hsp70) member 1 like; HW: BW heart weight:body weight ratio; I-R ischemia-reperfusion; ISO isoprenaline; MAP1LC3/LC3 microtubule associated protein 1 light chain 3; MBH membrane binding helix; MFN1 mitofusin 1; MFN2 mitofusin 2; Nam nicotinamide; TMRM tetramethylrhodamine ethyl ester; WGA wheat germ agglutinin.

Serum levels of IL-17 are elevated in patients with acute gouty arthritis.

Acute gouty arthritis (AGA) is one of the most common forms of auto-inflammatory arthritis. IL-17 is a key proinflammatory cytokine which has been implicated in several autoimmune diseases. However, to date little is known about the role of IL-17 in AGA. In the present study, we show that serum IL-17 levels are significantly elevated in AGA patients early in the onset of symptoms of gout, and decrease gradually as symptoms diminish. Correlation analysis indicated that IL-17 expression is not only positively correlated with disease activity, but is also correlated with serum levels of IL-1ß which plays a critical role in the differentiation of IL-17- γδT cells into IL-17+γδT cells. Flow cytometry analysis indicated that γδ T cells are a major source of IL-17 production during the early onset of AGA. We therefore identify IL-17 as a potential novel biomarker for AGA and suggest that targeting the γδ T cell/IL-17 immune axis is a potential strategy for treatment of acute flares of AGA.

Synthesis and antitumor activity of novel 2, 3-didithiocarbamate substituted naphthoquinones as inhibitors of pyruvate kinase M2 isoform.

The M2 isoform of pyruvate kinase (PKM2) is a potential antitumor therapeutic target. In this study, we designed and synthesised a series of 2, 3-didithiocarbamate substituted naphthoquinones as PKM2 inhibitors based on the lead compound 3k that we previously reported. Among them, compound 3f (IC50 = 1.05 ± 0.17 µM) and 3h (IC50 = 0.96 ± 0.18 µM) exhibited potent inhibition of PKM2, and their inhibitory activities are superior to compound 3k (IC50 = 2.95 ± 0.53 µM) and the known PKM2 inhibitor shikonin (IC50 = 8.82 ± 2.62 µM). In addition, we evaluated in vitro antiproliferative effects of target compounds using MTS assay. Most target compounds exhibited dose-dependent cytotoxicity with IC50 values in nanomolar concentrations against HCT116, MCF7, Hela, H1299 and B16 cells. These small molecule PKM2 inhibitors not only provide candidate compounds for cancer therapy, but also offer a tool to probe the biological effects of PKM2 inhibition on cancer cells.

Factors Associated With Detection of Helicobacter pylori in Gastric Biopsies: A Case-Control Study of 396 Biopsies.

AIM OF THE STUDY: Helicobacter pylori (HP) infection is associated with significant gastric mucosal inflammation. We aimed to determine the clinicopathologic features associated with HP in gastric biopsy. METHODS AND RESULTS: Three hundred ninety-six gastric biopsies were evaluated including 165 HP-positive cases and 231 randomly selected HP-negative controls. HP was detected using hematoxylin and eosin (H&E), Giemsa, and immunohistochemistry staining. The univariate and multivariate analyses were conducted to study the relationship of clinicopathologic characteristics and HP infection. Among the HP-positive cases, 131 cases were confirmed by H&E staining and 34 cases were confirmed by Giemsa or immunohistochemistry staining. Compared with chronic inactive gastritis, chronic active gastritis was more likely associated with having HP detected by H&E. Males were more likely to have HP gastritis than females (odds ratio: 1.72, P=0.01). The patients who had chronic active gastritis or chronic gastritis (moderate or severe) were more likely to have HP infection than patients with mild chronic gastritis (P<0.001). Conversely, patients who had intestinal metaplasia were less likely to have HP infection than patients without intestinal metaplasia (odds ratio: 0.22, P<0.001). However, concurrent atrophic gastritis was not related to HP infection (P=0.37). HP infection history was not associated with HP infection (P=0.74). CONCLUSIONS: HP detection in gastric biopsies is associated with active inflammation, male sex, and the lack of intestinal metaplasia, but not atrophic gastritis or HP infection history. Routine ancillary staining may not be required for HP detection in all biopsy specimens. We do not recommend ancillary staining for mild chronic inactive gastritis.

PTEN regulates spindle assembly checkpoint timing through MAD1 in interphase.

The spindle assembly checkpoint (SAC) restrains anaphase progression to ensure all chromosomes attach properly to the spindle. Although SAC timing has been extensively investigated in mitosis, its mechanism of regulation in interphase is unclear. We report that PTEN functions as a crucial activator of SAC timing and protects chromosome segregation under both spindle poison treated and untreated conditions. We show that PTEN physically interacts with MAD1 and promotes its dimerization and localization in the nuclear pore. Consequently, PTEN is important for the formation of the mitotic checkpoint complex (MCC) in interphase. We propose PTEN/MAD1 signaling is essential for maintenance of SAC timing and chromosome integrity.

Discovery of novel naphthoquinone derivatives as inhibitors of the tumor cell specific M2 isoform of pyruvate kinase.

Pyruvate kinase M2 (PKM2) is a rate-limiting enzyme of the glycolytic pathway which is highly expressed in cancer cells. Cancer cells rely heavily on PKM2 for anabolic and energy requirements, and specific targeting of PKM2 therefore has potential as strategy for cancer therapy. Here, we report the synthesis and biologic evaluation of novel naphthoquinone derivatives as selective small molecule inhibitors of PKM2. Some target compounds, such as compound 3k, displayed more potent PKM2 inhibitory activity than the reported optimal PKM2 inhibitor shikonin. The well performing compound 3k also showed nanomolar antiproliferative activity toward a series of cancer cell lines with high expression of PKM2 including HCT116, Hela and H1299 with IC50 values ranging from 0.18 to 1.56 µM. Moreover, compound 3k exhibited more cytotoxicity on cancer cells than normal cells. The identification of novel potent small molecule inhibitors of PKM2 not only offers candidate compounds for cancer therapy, but also provides a tool with which to evaluate the function of PKM2 in depth.

PTENα Modulates CaMKII Signaling and Controls Contextual Fear Memory and Spatial Learning.

PTEN (phosphatase and tensin homology deleted on chromosome 10) has multiple functions, and recent studies have shown that the PTEN family has isoforms. The roles of these PTEN family members in biologic activities warrant specific evaluation. Here, we show that PTENα maintains CaMKII in a state that is competent to induce long-term potentiation (LTP) with resultant regulation of contextual fear memory and spatial learning. PTENα binds to CaMKII with its distinctive N terminus and resets CaMKII to an activatable state by dephosphorylating it at sites T305/306. Loss of PTENα impedes the interaction of CaMKII and NR2B, leading to defects in hippocampal LTP, fear-conditioned memory, and spatial learning. Restoration of PTENα in the hippocampus of PTENα-deficient mice rescues learning deficits through regulation of CaMKII. CaMKII mutations in dementia patients inhibit CaMKII activity and result in disruption of PTENα-CaMKII-NR2B signaling. We propose that CaMKII is a target of PTENα phosphatase and that PTENα is an essential element in the molecular regulation of neural activity.

Protein Phosphatase 2A (PP2A) Regulates EG5 to Control Mitotic Progression.

EG5 (KIF11) is a member of the kinesin-like protein family involved in centrosome separation and bipolar spindle formation. When a cell enters mitosis, CDK1 phosphorylates EG5 at Thr926 and promotes EG5 localization on the mitotic spindle which drives bipolar spindle formation. EG5 provides power for spindle movement and thus controls the dynamics of spindle assembly. However, little is known about EG5 regulation or how EG5 detaches from the spindle upon mitotic exit. In this study we identify EG5 as a novel substrate of PP2A phosphatase, and we show that the PP2A/B55α complex plays an important role in mitotic exit by a mechanism involving EG5. The PP2A/B55α complex physically associates with the EG5 C-terminal tail domain and dephosphorylates EG5 at Thr926 that enables mitotic exit. Conversely PP2A knockdown cells show a high level of phospho-EG5 in late metaphase, which is associated with a delay in mitotic exit. These phenotypic features are similar to those induced by EG5/T926D transfection that mimics phosphorylated EG5 status. Our results argue that PP2A controls mitotic exit through EG5 dephosphorylation. Lack of PP2A leads to abnormal EG5 activation, resulting in delay of mitotic exit.

Eg5 inhibitor YL001 induces mitotic arrest and inhibits tumor proliferation.

Eg5 is a kinesin spindle protein that controls chromosomal segregation in mitosis and is thus a critical drug target for cancer therapy. We report the discovery of a potent, selective inhibitor of Eg5 designated YL001. YL001 was obtained through shape similarity based virtual screening, and it bears a 1,5-disubstituted tetrazole scaffold. YL001 exhibits favorable bioactivity in a variety of cancer cell lines, including taxol-resistant ovarian cancer and 6TG-resistant breast cancer cell lines. This compound inhibits tumor growth by 60% and significantly prolongs median survival time by more than 50% in a xenograft mouse model. YL001 blocks the ATPase activity of Eg5 and causes mitotic failure, ultimately resulting in apoptosis of cancer cells through activation of the caspase-3 pathway. Our findings demonstrate that YL001 is a potent antitumor agent that may be developed for cancer therapeutics.

PTENß is an alternatively translated isoform of PTEN that regulates rDNA transcription.

PTEN is a critical tumour suppressor that is frequently mutated in human cancer. We have previously identified a CUG initiated PTEN isoform designated PTENα, which functions in mitochondrial bioenergetics. Here we report the identification of another N-terminal extended PTEN isoform, designated PTENß. PTENß translation is initiated from an AUU codon upstream of and in-frame with the AUG initiation sequence for canonical PTEN. We show that the Kozak context and a downstream hairpin structure are critical for this alternative initiation. PTENß localizes predominantly in the nucleolus, and physically associates with and dephosphorylates nucleolin, which is a multifunctional nucleolar phosphoprotein. Disruption of PTENß alters rDNA transcription and promotes ribosomal biogenesis, and this effect can be reversed by re-introduction of PTENß. Our data show that PTENß regulates pre-rRNA synthesis and cellular proliferation. These results demonstrate the complexity of the PTEN protein family and the diversity of its functions.

USP9X destabilizes pVHL and promotes cell proliferation.

Numerous mutations of the Von Hippel-Lindau (VHL) gene have been reported to cause dysfunction of VHL protein (pVHL) and lead to processes related to tumor progression. pVHL acts as an E3 ligase and degrades downstream targets, such as hypoxia-inducible transcription factor (HIF) which is essential for tumor growth. Previous studies reported reduction of VHL protein, rather than mRNA in VHL-related tumor patients, suggesting that instability of the pVHL protein itself is a primary cause of dysfunction. Regulation of pVHL stability has therefore been a major focus of research. We report that ubiquitin-specific protease 9X (USP9X), which is a deubiquitinase binds and promotes degradation of both wild-type and mutants of pVHL that retain E3 ligase function, thus activating the HIF pathway. USP9X degrades pVHL through protection of its substrate, the newly identified pVHL E3 ligase Smurf1. In addition, USP9X activates glycolysis and promotes cell proliferation through pVHL. Treatment with a USP9X inhibitor shows an effect similar to USP9X knockdown in pVHL induction, and suppresses HIF activity. Our findings demonstrate that USP9X is a novel regulator of pVHL stability, and USP9X may be a therapeutic target for treatment of VHL-related tumors.

Simian Immunodeficiency Virus Impacts MicroRNA-16 Mediated Post-Transcriptional Regulation of mu Opioid Receptor in CEM ×174 Cells.

Although the mechanism which regulates transcription in the 5'-UTR of the mu opioid receptor gene (OPRM1) in lymphocytes has been well-studied, a question remains as to whether there is post-transcriptional regulation of OPRM1 gene in lymphocytes. In this study, the authors describe both the role played by miRNAs and the impact of SIVmac239 infection on post-transcriptional regulation of OPRM1 gene in CEM ×174 cells. Our results show that miR-16 is able to bind the target site in the range of 8699-8719 nt from the stop codon in MOR-1 mRNA 3'-UTR and suppress the expression of OPRM1 gene. Mutation of this target site reduces the effect of miR-16. Morphine (1 µM) inhibits the expression of miR-16, and this effect is reversed by the antagonist naloxone. Thus, morphine may up-regulate receptor level by both stimulating OPRM1 gene transcription and stabilizing its mRNA. SIVmac239 infection results in an apparent elevation of miR-16 and gradual reduction of OPRM1 gene expression. The inverse correlation of elevated miR-16 and reduced OPRM1 gene expression under viral loading confirmed the effect of SIVmac239 on post-transcriptional regulation of OPRM1 gene in lymphocytes. The authors conclude that miR-16 is a primary factor in post-transcriptional regulation of OPRM1 gene. SIVmac239 upregulates miR-16 levels and consequently suppresses OPRM1 gene expression. This finding will be helpful for full understanding of the regulatory mechanism of OPRM1 gene in lymphocytes, as well as the synergistic mechanism of HIV infection and morphine addiction in the pathogenesis of AIDS.

PTEN Controls the DNA Replication Process through MCM2 in Response to Replicative Stress.

PTEN is a tumor suppressor frequently mutated in human cancers. PTEN inhibits the phosphatidylinositol 3-kinase (PI3K)-AKT cascade, and nuclear PTEN guards the genome by multiple mechanisms. Here, we report that PTEN physically associates with the minichromosome maintenance complex component 2 (MCM2), which is essential for DNA replication. Specifically, PTEN dephosphorylates MCM2 at serine 41 (S41) and restricts replication fork progression under replicative stress. PTEN disruption results in unrestrained fork progression upon replication stalling, which is similar to the phenotype of cells expressing the phosphomimic MCM2 mutant S41D. Moreover, PTEN is necessary for prevention of chromosomal aberrations under replication stress. This study demonstrates that PTEN regulates DNA replication through MCM2 and loss of PTEN function leads to replication defects and genomic instability. We propose that PTEN plays a critical role in maintaining genetic stability through a replication-specific mechanism, and this is a crucial facet of PTEN tumor suppressor activity.