The androgen receptor (AR) has a central role in prostate cancer progression, particularly treatment-resistance disease including castration-resistant prostate cancer. Loss of the p53 tumor ...suppressor, a nuclear transcription factor, is also known to contribute to prostate malignancy. Here we report that p53 is translocated to the cytoplasm by androgen-mediated induction of G3BP2, a newly described direct target gene of AR. G3BP2 induces both cell cycle progression and blocks apoptosis. Translocation of p53 is regulated by androgen-dependent sumoylation mediated by the G3BP2-interacting SUMO-E3 ligase, RanBP2. G3BP2 knockdown results in reduced tumor growth and increased nuclear p53 accumulation in mouse xenograft models of prostate cancer with or without long-term androgen deprivation. Moreover, strong cytoplasmic p53 localization is correlated clinically with elevated G3BP2 expression and predicts poor prognosis and disease progression to the hormone-refractory state. Our findings reveal a new AR-mediated mechanism of p53 inhibition that promotes treatment-resistant prostate cancer.
Inflammation has an important role in cancer development through various mechanisms. It has been shown that dysregulation of microRNAs (miRNAs) that function as oncogenes or tumor suppressors ...contributes to tumorigenesis. However, the relationship between inflammation and cancer-related miRNA expression in tumorigenesis has not yet been fully understood. Using K19-C2mE and Gan mouse models that develop gastritis and gastritis-associated tumors, respectively, we found that 21 miRNAs were upregulated, and that 29 miRNAs were downregulated in gastric tumors in an inflammation-dependent manner. Among these miRNAs, the expression of miR-7, a possible tumor suppressor, significantly decreased in both gastritis and gastric tumors. Moreover, the expression of miR-7 in human gastric cancer was inversely correlated with the levels of interleukin-1β and tumor necrosis factor-α, suggesting that miR-7 downregulation is related to the severity of inflammatory responses. In the normal mouse stomach, miR-7 expression was at a basal level in undifferentiated gastric epithelial cells, and was induced during differentiation. Moreover, transfection of a miR-7 precursor into gastric cancer cells suppressed cell proliferation and soft agar colony formation. These results suggest that suppression of miR-7 expression is important for maintaining the undifferentiated status of gastric epithelial cells, and thus contributes to gastric tumorigenesis. Although epigenetic changes were not found in the CpG islands around miR-7-1 of gastritis and gastric tumor cells, we found that activated macrophage-derived small molecule(s) (<3 kDa) are responsible for miR-7 repression in gastric cancer cells. Furthermore, the miR-7 expression level significantly decreased in the inflamed gastric mucosa of Helicobacter-infected mice, whereas it increased in the stomach of germfree K19-C2mE and Gan mice wherein inflammatory responses were suppressed. Taken together, these results indicate that downregulation of tumor suppressor miR-7 is a novel mechanism by which the inflammatory response promotes gastric tumorigenesis.
Androgen receptor (AR) functions as a ligand-dependent transcription factor to regulate its downstream signaling for prostate cancer progression. AR complex formation by multiple transcription ...factors is important for enhancer activity and transcriptional regulation. However, the significance of such collaborative transcription factors has not been fully understood. In this study, we show that Oct1, an AR collaborative factor, coordinates genome-wide AR signaling for prostate cancer growth. Using global analysis by chromatin immunoprecipitation sequencing (ChIP-seq), we found that Oct1 is recruited to AR-binding enhancer/promoter regions and facilitates androgen signaling. Moreover, a major target of AR/Oct1 complex, acyl-CoA synthetase 3 (ACSL3), contributes to tumor growth in nude mice, and its high expression is associated with poor prognosis in prostate cancer patients. Next, we examined the therapeutic effects of pyrrole-imidazole polyamides that target the Oct1-binding sequence identified in the center of the ACSL3 AR-binding site. We observed that treatment with Oct1 polyamide severely blocked the Oct1 binding at the ACSL3 enhancer responsible for its transcriptional activity and ACSL3 induction. In addition, Oct1 polyamides suppressed castration-resistant tumor growth and specifically repressed global Oct1 chromatin association and androgen signaling in prostate cancer cells, with few nonspecific effects on basal promoter activity. Thus, targeting Oct1 binding could be a novel therapeutic strategy for AR-activated castration-resistant prostate cancer.
The Japanese domestic tobacco cultivar Kokubu (syn. Kou‐fan) is highly resistant to powdery mildew, and this trait is controlled by recessive alleles at two loci. To show the molecular mechanism of ...powdery mildew resistance of Kokubu, the transcripts and genomic sequences of tobacco Mildew resistance locus O (MLO) orthologues were compared between powdery mildew‐resistant and ‐susceptible cultivars. Two MLO orthologues (NtMLO1 and NtMLO2) corresponding to powdery mildew susceptibility were expressed in tobacco leaves. However, the transcripts of both NtMLO genes in the powdery mildew‐resistant cultivars harboured partial deletions or insertions. In a genomic DNA sequence alignment analysis, mutations in intron regions were detected in both NtMLO genes of powdery mildew‐resistant cultivars, and these mutations were linked to the powdery mildew‐resistant phenotype. Transgenic Kokubu expressing wildtype NtMLO1 or NtMLO2 exhibited severe disease symptoms, the same as those in susceptible cultivars. These results indicate that mutations of intron regions of two NtMLO genes in powdery mildew resistant cultivar Kokubu trigger the aberrant splicing of MLO transcripts and the subsequent inhibition of functional MLO protein synthesis, and that NtMLO1 and NtMLO2 are functionally redundant.
•Fatigue cracks originated from GBs, followed by the growth along the slip planes.•Heterogeneously precipitated δ-Ni2Si particles and PFZs were formed around GB areas.•The particles/PFZ-induced ...localized strain was main cause of the crack initiation.•There were a small number of DP grains which had negligible effects on fatigue strength.
Fatigue tests were conducted on round-bar specimens to understand the fatigue behavior of precipitate-strengthened Cu–6Ni–1.5Si alloy. Aging at 500°C for 0.5h produced δ-Ni2Si precipitates in the matrix, homogeneously and heterogeneously precipitated δ-Ni2Si particles, and a precipitate-free zone around the grain boundaries. The cracks were initiated at the grain boundaries, followed by growth along the crystallographic slip planes in the adjacent grains. Crack propagation from the crack origin along the grain boundaries was occasionally observed. The physical background of fatigue damage is discussed in light of the role of microstructure on the behavior of fatigue cracks.
Summary
Background
Taxanes are the current first‐line treatment for advanced cutaneous angiosarcoma (CAS) for patients who are considered difficult to treat with doxorubicin owing to advanced age or ...comorbidity. However, no effective second‐line therapy for such patients has been established.
Methods
We designed a single‐arm prospective observational study of eribulin mesylate (ERB) administered at a dose of 1·4 mg m−2 on days 1 and 8 in a 21‐day cycle. Patients with advanced CAS who were previously treated with a taxane and were scheduled to begin ERB treatment were enrolled. The primary endpoint was overall survival (OS) and the secondary endpoints were response rate (RR), progression‐free survival (PFS) and toxicity assessment.
Results
We enrolled a total of 25 patients. The median OS and PFS were 8·6 months and 3·0 months, respectively. The best overall RR was 20% (five of 25). In total, 16 grade 3/4 severe adverse events (SAEs) occurred; however, all patients recovered. Patients who achieved partial response or stable disease as best response had longer OS than those with progressive disease (median OS not reached and 3·3 months, respectively; P < 0·001). Patients who did not experience SAEs showed longer OS than those who did (median OS 18·8 months and 7·5 months, respectively; P < 0·05). Patients with distant metastasis had shorter median OS than those with locoregional disease, but without statistically significant difference.
Conclusions
ERB showed a promising RR and is a potential candidate for second‐line treatment for patients with CAS, after treatment with taxanes. However, owing to the occurrence of SAEs in over half of the participants, caution should be exercised regarding ERB use in elderly patients.
What is already known about this topic?
Taxanes are the current first‐line treatment for patients with advanced cutaneous angiosarcoma (CAS) who are considered difficult to treat with doxorubicin owing to advanced age or comorbidity.
No effective therapy for taxane‐resistant CAS has been established thus far.
Eribulin suppresses microtubule polymerization and elicits an antitumour effect similar to that of taxanes.
What does this study add?
In our single‐arm prospective observational study to evaluate the efficacy of eribulin for treating patients with advanced CAS who previously received taxanes, the median overall survival and progression‐free survival were 8·6 and 3·0 months, respectively.
Response rates at weeks 7, 13 and 25 were 20%, 17% and 14%, respectively.
Although 16 grade 3/4 severe adverse events occurred, all patients recovered.
Eribulin showed a promising response rate and is a potential candidate for second‐line treatment in CAS after taxane treatment.
Linked Comment: Smrke and Benson. Br J Dermatol 2020; 183:797–798.
What is already known about this topic?
Taxanes are the current first‐line treatment for patients with advanced cutaneous angiosarcoma (CAS) who are considered difficult to treat with doxorubicin owing to advanced age or comorbidity.
No effective therapy for taxane‐resistant CAS has been established thus far.
Eribulin suppresses microtubule polymerization and elicits an antitumour effect similar to that of taxanes.
What does this study add?
In our single‐arm prospective observational study to evaluate the efficacy of eribulin for treating patients with advanced CAS who previously received taxanes, the median overall survival and progression‐free survival were 8·6 and 3·0 months, respectively.
Response rates at weeks 7, 13 and 25 were 20%, 17% and 14%, respectively.
Although 16 grade 3/4 severe adverse events occurred, all patients recovered.
Eribulin showed a promising response rate and is a potential candidate for second‐line treatment in CAS after taxane treatment.
Linked Comment: Smrke and Benson. Br J Dermatol 2020; 183:797–798.
Background
Dermatophagoides farinae is a source of airborne house dust mite (HDM) allergens. We elucidated IgE‐reactive allergens from D. farinae by two‐dimensional immunoblotting‐based allergenome ...analysis, and identified one new allergen, named Der f 35, that possesses IgE‐binding capacity comparable to that of Der f 2. The aim of this study was to clarify the allergenic capacity of new HDM allergen Der f 35.
Methods
We cloned der f 35 from D. farinae mRNA and produced recombinant Der f 35 in Escherichia coli. The IgE‐binding capacity of Der f 35 and its cross‐reactivity with group 2 allergens from D. farinae and Psoroptes ovis were determined by enzyme‐linked immunosorbent assay (ELISA) and ELISA inhibition assays, respectively.
Results
The deduced amino acid sequence for der f 35, which possesses the MD‐2‐related lipid‐recognition domain, showed higher identity with group 2 allergens from P. ovis (61.5%) and Blomia tropicalis (50.7%) than with Der f 2 (40.8%). Der f 35 showed IgE‐binding frequencies of 77.5% (31/40) for the native form upon allergenome analysis and 51.4% (18/35) for recombinant structure by ELISA. Der f 35 showed cross‐reactivity with Der f 2 and Pso o 2 in reaction with HDM‐allergic patients' IgE by ELISA inhibition assay.
Conclusion
Der f 35 is a candidate major allergen from D. farinae, which is more similar to group 2 allergens from sheep scab mite and storage mites. Der f 35 could be responsible for the cross‐reactivity among group 2 mite allergens.
Human prostate cancer (PCa) is a highly heterogeneous and multifactorial disease. Current clinical biomarkers are not sufficiently accurate, thus being unable to predict the clinical outcome. ...Therefore, searching for new biomarkers aiming to improve diagnosis, prognosis and therapy is still required. In this study, we performed 3D Cell-SELEX against PC-3 prostate cancer cell line, a novel strategy to select specific nucleic acid ligands against spheroid cells in 3D cell culture. This original system combines Cell-SELEX, a process that exploits the cellular structure to generate specific ligands, and 3D cell culture, an approach that mimics the tissue microenvironment in vitro. In the first round of 3D Cell-SELEX, a negative selection against RWPE-1, non-tumor cell line, was performed to subtract non-tumor specific aptamers. The supernatant was used in eight additional rounds of selection, which were performed against PC-3 cell line. After nine selection cycles, eight PC-3 specific RNA aptamers were selected and sequenced. The aptamers presented sizes between 20 and 50 nucleotides-long, with low free energy (∆G<−13.6), which contributed for their spontaneous folding and high stability. Furthermore, our results showed the aptamer A4 as a specific ligand to prostate tumor cells, with dissociation constant in the nanomolar scale. Therefore, the novel 3D Cell-SELEX procedure improved the selection of PCa cell-surface ligands and the aptamer A4 has shown potential for the identification of prostate tumor cells, suggesting the application of this molecule in further screening assays for PCa.
•3D cell culture spheroids mimic the tumor microenvironment.•Aptamers selected in 3D cell culture is ideal for discovery of novel markers.•Small aptamers with spontaneous folding (−∆G) were enriched against tumor spheroids.•Aptamers may be used as potential markers for prostate cancer.
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