Cancer cell death induced by novel small molecules degrading the TACC3 protein via the ubiquitin-proteasome pathway

The selective degradation of target proteins with small molecules is a novel approach to the treatment of various diseases, including cancer. We have developed a protein knockdown system with a series of hybrid small compounds that induce the selective degradation of target proteins via the ubiquitin–proteasome pathway. In this study, we designed and synthesized novel small molecules called SNIPER(TACC3)s, which target the spindle regulatory protein transforming acidic coiled-coil-3 (TACC3). SNIPER(TACC3)s induce poly-ubiquitylation and proteasomal degradation of TACC3 and reduce the TACC3 protein level in cells. Mechanistic analysis indicated that the ubiquitin ligase APC/C^CDH1 mediates the SNIPER(TACC3)-induced degradation of TACC3. Intriguingly, SNIPER(TACC3) selectively induced cell death in cancer cells expressing a larger amount of TACC3 protein than normal cells. These results suggest that protein knockdown of TACC3 by SNIPER(TACC3) is a potential strategy for treating cancers overexpressing the TACC3 protein.

Protective effect of the long pentraxin PTX3 against histone-mediated endothelial cell cytotoxicity in sepsis

Pentraxin 3 (PTX3), a member of the long pentraxin subfamily within the family of pentraxins, is a soluble pattern recognition molecule that functions in the innate immune system. Innate immunity affords the infected host protection against sepsis, a potentially life-threatening inflammatory response to infection. Extracellular histones are considered to be the main cause of septic death because of their cytotoxic effect on endothelial cells, which makes them a potential therapeutic target. We found that PTX3 interacted with histones to form coaggregates, which depended on polyvalent interactions and disorder in the secondary structure of PTX3. PTX3 exerted a protective effect, both in vitro and in vivo, against histone-mediated cytotoxicity toward endothelial cells. Additionally, the intraperitoneal administration of PTX3 reduced mortality in mouse models of sepsis. The amino-terminal domain of PTX3, which was required for coaggregation with histones, was sufficient to protect against cytotoxicity. Our results suggest that the host-protective effects of PTX3 in sepsis are a result of its coaggregation with histones rather than its ability to mediate pattern recognition. This long pentraxin-specific effect provides a potential basis for the treatment of sepsis directed at protecting cells from the toxic effects of extracellular histones.

PPARβ/δ activation of CD300a controls intestinal immunity

Macrophages are important for maintaining intestinal immune homeostasis. Here, we show that PPARβ/δ (peroxisome proliferator-activated receptor β/δ) directly regulates CD300a in macrophages that express the immunoreceptor tyrosine based-inhibitory motif (ITIM)-containing receptor. In mice lacking CD300a, high-fat diet (HFD) causes chronic intestinal inflammation with low numbers of intestinal lymph capillaries and dramatically expanded mesenteric lymph nodes. As a result, these mice exhibit triglyceride malabsorption and reduced body weight gain on HFD. Peritoneal macrophages from Cd300a-/- mice on HFD are classically M1 activated. Activation of toll-like receptor 4 (TLR4)/MyD88 signaling by lipopolysaccharide (LPS) results in prolonged IL-6 secretion in Cd300a-/- macrophages. Bone marrow transplantation confirmed that the phenotype originates from CD300a deficiency in leucocytes. These results identify CD300a-mediated inhibitory signaling in macrophages as a critical regulator of intestinal immune homeostasis.

An analysis of the best method for evaluating anteversion of the acetabular component after total hip replacement on plain radiographs

Several radiological methods of measuring anteversion of the acetabular component after total hip replacement (THR) have been described. These studies used different definitions and reference planes to compare methods, allowing for misinterpretation of the results. We compared the reliability and accuracy of five current methods using plain radiographs (those of Lewinnek, Widmer, Liaw, Pradhan, and Woo and Morrey) with CT measurements, using the same definition and reference plane. We retrospectively studied the plain radiographs and CT scans in 84 hips of 84 patients who underwent primary THR. Intra- and inter-observer reliability were high for the measurement of inclination and anteversion with all methods on plain radiographs and CT scans. The measurements of inclination on plain radiographs were similar to the measurements using CT (p = 0.043). The mean difference between CT measurements was 0.6° (-5.9° to 6.8°).

Measurements using Widmer’s method were the most similar to those using CT (p = 0.088), with a mean difference between CT measurements of -0.9° (-10.4° to 9.1°), whereas the other four methods differed significantly from those using CT (p < 0.001).

This study has shown that Widmer’s method is the best for evaluating the anteversion of the acetabular component on plain radiographs.

Cite this article: Bone Joint J 2014; 96-B:597–603.

Identification of Wilms' tumor 1-associating protein complex and its role in alternative splicing and the cell cycle

Wilms' tumor 1-associating protein (WTAP) is a putative splicing regulator that is thought to be required for cell cycle progression through the stabilization of cyclin A2 mRNA and mammalian early embryo development. To further understand how WTAP acts in the context of the cellular machinery, we identified its interacting proteins in human umbilical vein endothelial cells and HeLa cells using shotgun proteomics. Here we show that WTAP forms a novel protein complex including Hakai, Virilizer homolog, KIAA0853, RBM15, the arginine/serine-rich domain-containing proteins BCLAF1 and THRAP3, and certain general splicing regulators, most of which have reported roles in post-transcriptional regulation. The depletion of these respective components of the complex resulted in reduced cell proliferation along with G2/M accumulation. Double knockdown of the serine/arginine-rich (SR)-like proteins BCLAF1 and THRAP3 by siRNA resulted in a decrease in the nuclear speckle localization of WTAP, whereas the nuclear speckles were intact. Furthermore, we found that the WTAP complex regulates alternative splicing of the WTAP pre-mRNA by promoting the production of a truncated isoform, leading to a change in WTAP protein expression. Collectively, these findings show that the WTAP complex is a novel component of the RNA processing machinery, implying an important role in both posttranscriptional control and cell cycle regulation.

Dose-dependent differential effects of thrombin in allergic bronchial asthma

BACKGROUND

Apart from its role in the coagulation system, thrombin plays an important role in the inflammatory response through its protease-activated receptors (PARs). However, the role of thrombin in the immune response is not clear.

OBJECTIVE

To evaluate whether thrombin has a modulatory role in allergic bronchial asthma.

METHODS

Bronchial asthma was induced in mice by intraperitoneal sensitization and inhalation challenge with ovalbumin. Thrombin or its inhibitors were administered by inhalation before each allergen challenge.

RESULTS

Mice with low but sustained coagulation activation had reduced allergic inflammation, and allergic asthma was inhibited by low doses of thrombin but worsened by high doses. Allergic asthma was worsened by antithrombin, argatroban, hirudin, and anti-thrombomodulin antibody. Mice with a higher level of an inhibitor of both thrombin and activated protein C had worse disease. Heterozygous PAR-1 mice had less allergic inflammation, but PAR-1 agonist worsened it. Allergic bronchial inflammation was worsened in mice that received adoptive transfer of PAR-1 agonist-treated Th2 cells as compared with controls. Low levels of thrombin suppressed the maturation and secretion of cytokines in dendritic cells, but high levels enhanced this.

CONCLUSIONS

The effects of thrombin on allergic asthma are dose-dependent, with detrimental effects at high doses and protective effects at low doses. These data demonstrate that thrombin modulates the outcome in allergic bronchial asthma.

Androgen deprivation promotes intratumoral synthesis of dihydrotestosterone from androgen metabolites in prostate cancer

Intratumoral synthesis of dihydrotestosterone (DHT) from precursors cannot completely explain the castration resistance of prostate cancer. We showed that DHT was intratumorally synthesized from the inactive androgen metabolites 5α-androstane-3α/β,17β-diol (3α/β-diol) in prostate cancer cells via different pathways in a concentration-dependent manner. Additionally, long-term culture in androgen-deprived media increased transcriptomic expression of 17β-hydroxysteroid dehydrogenase type 6 (HSD17B6), a key enzyme of oxidative 3α-HSD that catalyzes the conversion of 3α-diol to DHT in prostate cancer cells. Correspondingly, the score for HSD17B6 in tissues of 42 prostate cancer patients undergoing androgen deprivation therapy (ADT) was about 2-fold higher than that in tissues of 100 untreated individuals. In men receiving ADT, patients showing biochemical progression had a higher HSD17B6 score than those without progression. These results suggested that 3α/β-diol also represent potential precursors of DHT, and the back conversion of DHT from androgen derivatives can be a promising target for combination hormone therapy.

The calcineurin-NFAT-angiopoietin-2 signaling axis in lung endothelium is critical for the establishment of lung metastases

The premetastatic niche is a predetermined site of metastases, awaiting the influx of tumor cells. However, the regulation of the angiogenic switch at these sites has not been examined. Here, we demonstrate that the calcineurin and nuclear factor of activated T cells (NFAT) pathway is activated specifically in lung endothelium prior to the detection of tumor cells that preferentially metastasize to the lung. Upregulation of the calcineurin pathway via deletion of its endogenous inhibitor Dscr1 leads to a significant increase in lung metastases due to increased expression of a newly identified NFAT target, Angiopoietin-2 (ANG2). Increased VEGF levels specifically in the lung, and not other organ microenvironments, trigger a threshold of calcineurin-NFAT signaling that transactivates Ang2 in lung endothelium. Further, we demonstrate that overexpression of DSCR1 or the ANG2 receptor, soluble TIE2, prevents the activation of lung endothelium, inhibiting lung metastases in our mouse models. Our studies provide insights into mechanisms underlying angiogenesis in the premetastatic niche and offer targets for lung metastases.

Chronological changes of delayed-type hypersensitivity in mice immunised with testicular germ cells alone

Experimental autoimmune orchitis (EAO), comprising a breakdown of the testicular immune privilege, is one of the models of immunological male infertility. EAO is characterised by CD4 + T-cell-dependent lymphocytic inflammation and augmented delayed-type hypersensitivity (DTH) against testicular antigens. We previously established an EAO model in mice by immunisation with viable syngeneic testicular germ cells (TGC) alone. However, the sequential change of DTH during development of this EAO has not been analysed yet. In this study, the DTH response during TGC-induced EAO was investigated by the injection of syngeneic TGC protein into the ears of mice. The results showed that a significant DTH response was observed on injection of 20 μg TGC protein, but not on that of 0.2 or 2 μg TGC protein. Also, the level of the DTH response to 20 μg TGC protein was highly relevant to the pathology of EAO development. These results indicate that the DTH response on injection of 20 μg TGC protein into the ears of mice is effective for predicting the pathology of EAO development.

Immunoglobulin G4-related disease with several inflammatory foci

We herein report the case of a 62-year-old Japanese man who presented with jaundice, dry eyes and abdominal discomfort. Imaging studies revealed swelling of the periorbital tissue, parotid and submandibular glands, pulmonary hilar lymph nodes, pancreas, bile ducts, gall bladder walls, bilateral kidneys, arterial walls and prostate. A significant increase in the serum level IgG4 was seen, and the patient was diagnosed with IgG4-related disease after undergoing a biopsy of the pancreas and prostate. We herein report a case of IgG4-related disease with multiple ten organ involvement at the onset of the disease that was successfully treated with prednisolone (PSL) therapy.

Phosphatidylinositol 3-phosphatase myotubularin-related protein 6 (MTMR6) is regulated by small GTPase Rab1B in the early secretory and autophagic pathways

A large family of myotubularin phosphatases dephosphorylates phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-bisphosphate, which are known to play important roles in vesicular trafficking and autophagy. The family is composed of 16 members, and understanding their regulatory mechanisms is important to understand their functions and related genetic diseases. We prepared anti-myotubularin-related protein 6 (MTMR6) monoclonal antibody and used it to study the regulatory mechanism of MTMR6. Endogenous MTMR6 was present in the cytoplasm and was condensed in the perinuclear region in a microtubule-dependent manner. MTMR6 preferentially interacted with GDP-bound Rab1B via the GRAM domain and partly overlapped with Rab1B in the pericentrosomal and peri-Golgi regions in normal rat kidney cells. Overexpression of GDP-bound Rab1B and the reduction of Rab1B disrupted the localization of MTMR6, suggesting that Rab1B regulates the localization of MTMR6. The reduction of MTMR6 accelerated the transport of vesicular stomatitis virus glycoprotein in which Rab1B is involved. Furthermore, reduction of MTMR6 or Rab1B inhibited the formation of the tubular omegasome that is induced by overexpression of DFCP1 in autophagy. Our results indicate that the cellular localization of MTMR6 is regulated by Rab1B in the early secretory and autophagic pathways. We propose a new regulatory mechanism of myotubularin phosphatase by the small GTPase Rab1B.

Delayed emergence of oseltamivir-resistant seasonal influenza A (H1N1) and pandemic influenza A(H1N1)pdm09 viruses in Myanmar

Please cite this paper as: Dapat et al. (2012) Delayed emergence of oseltamivir‐resistant seasonal influenza A (H1N1) and pandemic influenza A(H1N1)pdm09 viruses in Myanmar. Influenza and Other Respiratory Viruses DOI: 10.1111/irv.12030.

The prevalence and timing of emergence of oseltamivir‐resistant seasonal and pandemic influenza A (H1N1) viruses in Myanmar in 2008 and 2009 are described in this report. In 2008, the oseltamivir‐resistant seasonal H1N1 virus was detected at a lower rate (6%) and emerged at least 2 months later when compared with neighboring countries. Similarly, the prevalence of pandemic H1N1 virus was low (3%) and the timing of emergence was late (August 2009) in Myanmar. Interestingly, we detected three isolates that were resistant to both amantadine and oseltamivir. Limited movement of people into the country is attributed to the delayed emergence of drug‐resistant seasonal and pandemic A(H1N1) viruses.

Induced pluripotent stem cells generated from diabetic patients with mitochondrial DNA A3243G mutation

AIMS/HYPOTHESIS

The aim of this study was to generate induced pluripotent stem (iPS) cells from patients with mitochondrial DNA (mtDNA) mutation.

METHODS

Skin biopsies were obtained from two diabetic patients with mtDNA A3243G mutation. The fibroblasts thus obtained were infected with retroviruses encoding OCT4 (also known as POU5F1), SOX2, c-MYC (also known as MYC) and KLF4. The stem cell characteristics were investigated and the mtDNA mutation frequencies evaluated by Invader assay.

RESULTS

From the two diabetic patients we isolated four and ten putative mitochondrial disease-specific iPS (Mt-iPS) clones, respectively. Mt-iPS cells were cytogenetically normal and positive for alkaline phosphatase activity, with the pluripotent stem cell markers being detectable by immunocytochemistry. The cytosine guanine dinucleotide islands in the promoter regions of OCT4 and NANOG were highly unmethylated, indicating epigenetic reprogramming to pluripotency. Mt-iPS clones were able to differentiate into derivatives of all three germ layers in vitro and in vivo. The Mt-iPS cells exhibited a bimodal degree of mutation heteroplasmy. The mutation frequencies decreased to an undetectable level in six of 14 clones, while the others showed several-fold increases in mutation frequencies (51-87%) compared with those in the original fibroblasts (18-24%). During serial cell culture passage and after differentiation, no recurrence of the mutation or no significant changes in the levels of heteroplasmy were seen.

CONCLUSIONS/INTERPRETATION

iPS cells were successfully generated from patients with the mtDNA A3243G mutation. Mutation-rich, stable Mt-iPS cells may be a suitable source of cells for human mitochondrial disease modelling in vitro. Mutation-free iPS cells could provide an unlimited, disease-free supply of cells for autologous transplantation therapy.

Abstract 960: Intratumoral dihydrotestosterone regulation by conversion of androstanediol to dihydrotestosterone in prostate cancer

Purpose It has become apparent that resurgent androgen receptor activity in castration-resistant prostate cancer can be accounted for in part through intratumoral androgen synthesis. The potent androgen dihydrotestosterone (DHT) yields an inactive androgen 5α-androstane-3α17α-diol (androstanediol/3α-diol) in the prostate. The metabolism of 3α-diol and relationships among other androgens have not been elucidated. Therefore, we studied the metabolism of 3α-diol in prostate cancer cells, as well as the expression of 17α-hydroxysteroid dehydrogenase 6 (17α-HSD6), a key enzyme of oxidative 3α-HSD that converts 3α-diol into DHT, in prostate cancer cells and tissues using real time-PCR and immunohistochemistry. Finally, we studied the correlation between serum 3α-diol G levels and androgens in localized prostate cancer patients. Methods LNCaP and VCaP cells were cultured in the hormone-depleted medium with presence/absence of 3α-diol, and the intracellular levels of androstenedione, testosterone and DHT were concurrently determined by liquid chromatography tandem mass spectrometry. LNCaP and VCaP cells were exposed to 3α-diol and bicalutamide in various concentrations. Prostate-specific antigen (PSA) levels in media were assayed. To examine the long term effect of androgen deprivation, LNCaP was cultured in hormone-depleted medium with 1nM DHEA. Transcriptome expression was analyzed to detect expression levels of 17α-HSD6. Expression scores for 17α-HSD6 in radical prostatectomy specimens treated with or without androgen deprivation therapy (ADT) were evaluated using immunohistochemistry. Seventy-two patients with localized prostate cancer patients were prospectively studied based on blood samples before and after ADT for 6 months. Results DHT was synthesized from 3α-diol in prostate cancer cells. Prostate cancer cells produced PSA in a dose-dependent manner with 3α-diol. Prostate cancer cells pretreated with 3α-diol showed a dose-dependent decrease in PSA production with bicalutamide. In the lower passages LNCaP cells treated with DHEA, expression of 17α-HSD6 showed much less striking change. However, in the higher passage LNCaP cells, 17α-HSD6 was up-regulated. The score for 17α-HSD6 in prostate cancer tissues treated with ADT was significantly higher than that without ADT (p&lt;0.001). There were significant positive relationships between serum DHEA-S and 3α-diol G levels before and after ADT. Conclusion We verified the synthesis of DHT from 3α-diol in prostate cancer cells in this study and elucidated that the serum 3α-diol G level well reflects the adrenal androgen milieu in localized prostate cancer patients. Therefore, 3α-diol can be a potential precursor of the most active androgen DHT in prostate cancer. Our data suggest that the adrenal androgen-DHT axis can be a potential therapeutic target for treating prostate cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 960. doi:1538-7445.AM2012-960

Efficient palliative involved-field radiotherapy on highly progressive diffuse large B-cell primary gastric lymphoma with liver cirrhosis

We report the case of a 73-year-old woman having diffuse large B-cell primary gastric lymphoma with a cirrhotic liver caused by hepatitis C virus infection. She visited our hospital with symptoms of nausea and vomiting, which appeared to be caused by stenosis due to the tumor. Metastatic tumors were seen in the gastric and jugular lymph nodes. The clinical stage was IVB with a high risk of poor prognosis according to the international index. Because of poor hepatic reserve function, standard chemotherapy could not be administered. To maintain her quality of life, palliative involved-field radiotherapy was performed. The symptoms and tumor markers significantly improved, and computed tomography and endoscopy indicated the disappearance of the primary gastric tumor. Two months after radiotherapy and her return home, she died of pneumonia. Autopsy showed neither lymphoma cells nor stenosis of gastric lesion. The significant anti-tumor effect on primary tumor in our case suggests that the involved-field radiotherapy, although palliative, can be a therapeutic option for primary gastric lymphoma patients with various complications.