A single oncogenic enhancer rearrangement causes concomitant EVI1 and GATA2 deregulation in leukemia

Chromosomal rearrangements without gene fusions have been implicated in leukemogenesis by causing deregulation of proto-oncogenes via relocation of cryptic regulatory DNA elements. AML with inv(3)/t(3;3) is associated with aberrant expression of the stem-cell regulator EVI1. Applying functional genomics and genome-engineering, we demonstrate that both 3q rearrangements reposition a distal GATA2 enhancer to ectopically activate EVI1 and simultaneously confer GATA2 functional haploinsufficiency, previously identified as the cause of sporadic familial AML/MDS and MonoMac/Emberger syndromes. Genomic excision of the ectopic enhancer restored EVI1 silencing and led to growth inhibition and differentiation of AML cells, which could be replicated by pharmacologic BET inhibition. Our data show that structural rearrangements involving the chromosomal repositioning of a single enhancer can cause deregulation of two unrelated distal genes, with cancer as the outcome.

Human papillomavirus 16 load in normal and abnormal cervical scrapes: an indicator of CIN II/III and viral clearance

The relation between human papillomavirus type 16 (HPV 16) viral load in cervical scrapes and development of high-grade cervical intraepithelial neoplasia (CIN II or III) was studied in a nested case-control study of women with normal cytology (group A) and in a cohort of women with abnormal cytology (group B). HPV 16 DNA load was determined using a quantitative real-time PCR assay. In group A, case women (women with CIN II/III, n = 12) had a significantly higher viral load than control women (women with CIN < or = I, n = 47). This resulted in an increased relative risk of women with the 50% highest viral load for development of CIN II/III (OR 7.7; CI 1.6-33). In group B, women with CIN II/III (n = 38) had a significantly higher viral load than women with CIN < or = I (n = 25). Women with the 50% highest viral load had an increased relative risk of CIN II/III (OR 3.2; CI 1.1-9.3) and a decreased chance of both viral clearance and cytologic regression. Our data suggest that in women with normal cytology an increased HPV 16 load confers an increased risk of developing a CIN lesion. A sustained high viral load is subsequently informative for progression to a high-grade CIN lesion.

Mechanisms of peripheral neuropathy associated with bortezomib and vincristine in patients with newly diagnosed multiple myeloma: a prospective analysis of data from the HOVON-65/GMMG-HD4 trial

BACKGROUND

Bortezomib-induced peripheral neuropathy is a dose-limiting toxicity in patients with multiple myeloma, often requiring adjustment of treatment and affecting quality of life. We investigated the molecular profiles of early-onset (within one treatment cycle) versus late-onset (after two or three treatment cycles) bortezomib-induced peripheral neuropathy and compared them with those of vincristine-induced peripheral neuropathy during the induction phase of a prospective phase 3 trial.

METHODS

In the induction phase of the HOVON-65/GMMG-HD4 trial, patients (aged 18-65 years) with newly diagnosed Salmon and Durie stage 2 or 3 multiple myeloma were randomly assigned to three cycles of bortezomib-based or vincristine-based induction treatment. We analysed the gene expression profiles and single-nucleotide polymorphisms (SNPs) of pretreatment samples of myeloma plasma cells and peripheral blood, respectively. This study is registered, number ISRCTN64455289.

FINDINGS

We analysed gene expression profiles of myeloma plasma cells from 329 (39%) of 833 patients at diagnosis, and SNPs in DNA samples from 369 (44%) patients. Early-onset bortezomib-induced peripheral neuropathy was noted in 20 (8%) patients, and 63 (25%) developed the late-onset type. Early-onset and late-onset vincristine-induced peripheral neuropathy was noted in 11 (4%) and 17 (7%) patients, respectively. Significant genes in myeloma plasma cells from patients that were associated with early-onset bortezomib-induced peripheral neuropathy were the enzyme coding genes RHOBTB2 (upregulated by 1·59 times; p=4·5×10(-5)), involved in drug-induced apoptosis, CPT1C (1·44 times; p=2·9×10(-7)), involved in mitochondrial dysfunction, and SOX8 (1·68 times; p=4·28×10(-13)), involved in development of peripheral nervous system. Significant SNPs in the same patients included those located in the apoptosis gene caspase 9 (odds ratio [OR] 3·59, 95% CI 1·59-8·14; p=2·9×10(-3)), ALOX12 (3·50, 1·47-8·32; p=3·8×10(-3)), and IGF1R (0·22, 0·07-0·77; p=8·3×10(-3)). In late-onset bortezomib-induced peripheral neuropathy, the significant genes were SOD2 (upregulated by 1·18 times; p=9·6×10(-3)) and MYO5A (1·93 times; p=3·2×10(-2)), involved in development and function of the nervous system. Significant SNPs were noted in inflammatory genes MBL2 (OR 0·49, 95% CI 0·26-0·94; p=3·0×10(-2)) and PPARD (0·35, 0·15-0·83; p=9·1×10(-3)), and DNA repair genes ERCC4 (2·74, 1·56-4·84; p=1·0×10(-3)) and ERCC3 (1·26, 0·75-2·12; p=3·3×10(-3)). By contrast, early-onset vincristine-induced peripheral neuropathy was characterised by upregulation of genes involved in cell cycle and proliferation, including AURKA (3·31 times; p=1·04×10(-2)) and MKI67 (3·66 times; p=1·82×10(-3)), and the presence of SNPs in genes involved in these processes-eg, GLI1 (rs2228224 [0·13, 0·02-0·97, p=1·18×10(-2)] and rs2242578 [0·14, 0·02-1·12, p=3·00×10(-2)]). Late-onset vincristine-induced peripheral neuropathy was associated with the presence of SNPs in genes involved in absorption, distribution, metabolism, and excretion-eg, rs1413239 in DPYD (3·29, 1·47-7·37, 5·40×10(-3)) and rs3887412 in ABCC1 (3·36, 1·47-7·67, p=5·70×10(-3)).

INTERPRETATION

Our results strongly suggest an interaction between myeloma-related factors and the patient's genetic background in the development of treatment-induced peripheral neuropathy, with different molecular pathways being implicated in bortezomib-induced and vincristine-induced peripheral neuropathy.

Genome-wide association study identifies multiple susceptibility loci for multiple myeloma

Multiple myeloma (MM) is a plasma cell malignancy with a significant heritable basis. Genome-wide association studies have transformed our understanding of MM predisposition, but individual studies have had limited power to discover risk loci. Here we perform a meta-analysis of these GWAS, add a new GWAS and perform replication analyses resulting in 9,866 cases and 239,188 controls. We confirm all nine known risk loci and discover eight new loci at 6p22.3 (rs34229995, P=1.31 × 10(-8)), 6q21 (rs9372120, P=9.09 × 10(-15)), 7q36.1 (rs7781265, P=9.71 × 10(-9)), 8q24.21 (rs1948915, P=4.20 × 10(-11)), 9p21.3 (rs2811710, P=1.72 × 10(-13)), 10p12.1 (rs2790457, P=1.77 × 10(-8)), 16q23.1 (rs7193541, P=5.00 × 10(-12)) and 20q13.13 (rs6066835, P=1.36 × 10(-13)), which localize in or near to JARID2, ATG5, SMARCD3, CCAT1, CDKN2A, WAC, RFWD3 and PREX1. These findings provide additional support for a polygenic model of MM and insight into the biological basis of tumour development.

High cereblon expression is associated with better survival in patients with newly diagnosed multiple myeloma treated with thalidomide maintenance

Recently, cereblon (CRBN) expression was found to be essential for the activity of thalidomide and lenalidomide. In the present study, we investigated whether the clinical efficacy of thalidomide in multiple myeloma is associated with CRBN expression in myeloma cells. Patients with newly diagnosed multiple myeloma were included in the HOVON-65/GMMG-HD4 trial, in which postintensification treatment in 1 arm consisted of daily thalidomide (50 mg) for 2 years. Gene-expression profiling, determined at the start of the trial, was available for 96 patients who started thalidomide maintenance. In this patient set, increase of CRBN gene expression was significantly associated with longerprogression-free survival (P = .005). In contrast, no association between CRBN expression and survival was observed in the arm with bortezomib maintenance. We conclude that CRBN expression may be associated with the clinical efficacy of thalidomide. This trial has been registered at the Nederlands Trial Register (www.trialregister.nl) as NTR213; at the European Union Drug Regulating Authorities Clinical Trials (EudraCT) as 2004-000944-26; and at the International Standard Randomized Controlled Trial Number (ISRCTN) as 64455289.

The role of EXT1 in nonhereditary osteochondroma: identification of homozygous deletions

BACKGROUND

Multiple osteochondromas is a hereditary syndrome that is characterized by the formation of cartilage-capped bony neoplasms (osteochondromas), for which exostosis (multiple)-1 (EXT1) has been identified as a causative gene. However, 85% of all osteochondromas present as solitary (nonhereditary) lesions in which somatic mutations in EXT1 are extremely rare, but loss of heterozygosity and clonal rearrangement of 8q24 (the chromosomal locus of EXT1) are common. We examined whether EXT1 might act as a classical tumor suppressor gene for nonhereditary osteochondromas.

METHODS

Eight nonhereditary osteochondromas were subjected to high-resolution array-based comparative genomic hybridization (array-CGH) analysis for chromosome 8q. The array-CGH results were validated by subjecting tumor DNA to multiple ligation-dependent probe amplification (MLPA) analysis for EXT1. EXT1 locus-specific fluorescent in situ hybridization (FISH) was performed on nuclei isolated from the three tissue components of osteochondroma (cartilage cap, perichondrium, bony stalk) to examine which parts of the tumor are of clonal origin.

RESULTS

Array-CGH analysis of tumor DNA revealed that all eight osteochondromas had a large deletion of 8q; five tumors had an additional small deletion of the other allele of 8q that contained the EXT1 gene. MLPA analysis of tumor DNA confirmed these findings and identified two additional deletions that were smaller than the limit of resolution of array-CGH. FISH analysis of the cartilage cap, perichondrium, and bony stalk showed that these homozygous EXT1 deletions were present only in the cartilage cap of osteochondroma.

CONCLUSION

EXT1 functions as a classical tumor suppressor gene in the cartilage cap of nonhereditary osteochondromas.

Cancer-selective targeting of the NF-κB survival pathway with GADD45β/MKK7 inhibitors

Constitutive NF-κB signaling promotes survival in multiple myeloma (MM) and other cancers; however, current NF-κB-targeting strategies lack cancer cell specificity. Here, we identify the interaction between the NF-κB-regulated antiapoptotic factor GADD45β and the JNK kinase MKK7 as a therapeutic target in MM. Using a drug-discovery strategy, we developed DTP3, a D-tripeptide, which disrupts the GADD45β/MKK7 complex, kills MM cells effectively, and, importantly, lacks toxicity to normal cells. DTP3 has similar anticancer potency to the clinical standard, bortezomib, but more than 100-fold higher cancer cell specificity in vitro. Notably, DTP3 ablates myeloma xenografts in mice with no apparent side effects at the effective doses. Hence, cancer-selective targeting of the NF-κB pathway is possible and, at least for myeloma patients, promises a profound benefit.

Identification of multiple risk loci and regulatory mechanisms influencing susceptibility to multiple myeloma

Genome-wide association studies (GWAS) have transformed our understanding of susceptibility to multiple myeloma (MM), but much of the heritability remains unexplained. We report a new GWAS, a meta-analysis with previous GWAS and a replication series, totalling 9974 MM cases and 247,556 controls of European ancestry. Collectively, these data provide evidence for six new MM risk loci, bringing the total number to 23. Integration of information from gene expression, epigenetic profiling and in situ Hi-C data for the 23 risk loci implicate disruption of developmental transcriptional regulators as a basis of MM susceptibility, compatible with altered B-cell differentiation as a key mechanism. Dysregulation of autophagy/apoptosis and cell cycle signalling feature as recurrently perturbed pathways. Our findings provide further insight into the biological basis of MM.

High-resolution array comparative genomic hybridization of chromosome arm 8q: evaluation of genetic progression markers for prostate cancer

Copy number increase of 8q has previously been shown to be associated with a poor clinical outcome and tumor recurrence in patients with prostate cancer. In this study, a detailed genomic analysis of 8q was performed of archival primary and metastatic prostatic adenocarcinomas (n = 22), and prostate cancer xenografts (n = 9), and cell lines (n = 3). We performed array comparative genomic hybridization (aCGH) using a whole chromosome arm contig array consisting of 702 8q-specific BAC clones. Five regions of frequent copy number increase were identified, i.e. at chromosome bands 8q21.13 (81-82 Mb), 8q22.1 (94-96 Mb), 8q22.2-3 (101-103 Mb), 8q24.13 (124-126 Mb), and 8q24.21 (127-129 Mb), the most distal region containing the MYC oncogene. MYC and 13 genes of the other four regions with putative relevance to cancer were selected. Two additional genes were derived from high-level amplifications detected by 8q aCGH analysis of prostate cancer xenograft PC339. Quantitative RT-PCR of these 16 genes was performed in a series of 26 prostate specimens, including normal tissue (n = 5), fresh-frozen adenocarcinoma (n = 7), cancer xenograft (n = 9), and cancer cell line material (n = 2). Three of the 16 genes were significantly overexpressed in cancer compared with that in normal prostate tissue, i.e. PDP, located at 8q22.1 (95 Mb), PABPC1 located at 8q22.3 (102 Mb), and KIAA0196 located at 8q24.13 (126 Mb). These genes can be considered putative progression markers for prostate cancer.

P, Anderson KC, Li C, Avet-Loiseau H, Munshi NC. Gene expression profile alone is inadequate in predicting complete response in multiple myeloma

With advent of several treatment options in multiple myeloma (MM), a selection of effective regimen has become an important issue. Use of gene expression profile (GEP) is considered an important tool in predicting outcome; however, it is unclear whether such genomic analysis alone can adequately predict therapeutic response. We evaluated the ability of GEP to predict complete response (CR) in MM. GEP from pretreatment MM cells from 136 uniformly treated MM patients with response data on an IFM, France led study were analyzed. To evaluate variability in predictive power due to microarray platform or treatment types, additional data sets from three different studies (n=511) were analyzed using same methods. We used several machine learning methods to derive a prediction model using training and test subsets of the original four data sets. Among all methods employed for GEP-based CR predictive capability, we got accuracy range of 56-78% in test data sets and no significant difference with regard to GEP platforms, treatment regimens or in newly diagnosed or relapsed patients. Importantly, permuted P-value showed no statistically significant CR predictive information in GEP data. This analysis suggests that GEP-based signature has limited power to predict CR in MM, highlighting the need to develop comprehensive predictive model using integrated genomics approach.

Cancer testis antigens in newly diagnosed and relapse multiple myeloma: prognostic markers and potential targets for immunotherapy

BACKGROUND

In multiple myeloma, expression of cancer testis antigens may provide prognostic markers and potential targets for immunotherapy. Expression at relapse has not yet been evaluated for a large panel of cancer testis antigens which can be classified by varying expression in normal tissue: restricted to testis, expressed in testis and brain and not restricted but selectively expressed in testis.

DESIGN AND METHODS

Evaluation of cancer testis antigen expression was made in newly diagnosed multiple myeloma cases (HOVON-65/GMMG-HD4 trial; n = 320) and in relapse cases (APEX, SUMMIT, CREST trials; n = 264). Presence of expression using Affymetrix GeneChips was determined for 123 cancer testis antigens. Of these 87 had a frequency of more than 5% in the newly diagnosed and relapsed patients, and were evaluated in detail.

RESULTS

Tissue restriction was known for 58 out of 87 cancer testis antigens. A significantly lower frequency of presence calls in the relapsed compared to newly diagnosed cases was found for 3 out of 13 testis restricted genes, 2 out of 7 testis/brain restricted genes, and 17 out of 38 testis selective genes. MAGEC1, MAGEB2 and SSX1 were the most frequent testis-restricted cancer testis antigens in both data sets. Multivariate analysis demonstrated that presence of MAGEA6 and CDCA1 were clearly associated with shorter progression free survival, and presence of MAGEA9 with shorter overall survival in the set of newly diagnosed cases. In the set of relapse cases, presence of CTAG2 was associated with shorter progression free survival and presence of SSX1 with shorter overall survival.

CONCLUSIONS

Relapsed multiple myeloma reveals extensive cancer testis antigen expression. Cancer testis antigens are confirmed as useful prognostic markers in newly diagnosed multiple myeloma patients and in relapsed multiple myeloma patients. The HOVON-65/GMMG-HD4 trial is registered under Dutch trial register n. NTR-213. CREST, SUMMIT and APEX trials were registered under ns. M34100-024, M34100-025 and NCT00049478/NCT00048230, respectively.

The myeloma stem cell concept, revisited: from phenomenology to operational terms

The concept of the myeloma stem cell may have important therapeutic implications, yet its demonstration has been hampered by a lack of consistency in terms and definitions. Here, we summarize the current documentation and propose single-cell in vitro studies for future translational studies. By the classical approach, a CD19^-/CD45^low/-/CD38^high/CD138⁺ malignant plasma cell, but not the CD19⁺/CD38^low/- memory B cell compartment, is enriched for tumorigenic cells that initiate myeloma in xenografted immunodeficient mice, supporting that myeloma stem cells are present in the malignant PC compartment. Using a new approach, analysis of c-DNA libraries from CD19⁺/CD27⁺/CD38^- single cells has identified clonotypic memory B cell, suggested to be the cell of origin. This is consistent with multiple myeloma being a multistep hierarchical process before or during clinical presentation. We anticipate that further characterization will require single cell geno- and phenotyping combined with clonogenic assays. To implement such technologies, we propose a revision of the concept of a myeloma stem cell by including operational in vitro assays to describe the cellular components of origin, initiation, maintenance, and evolution of multiple myeloma. These terms are in accordance with recent (2012) consensus statements on the definitions, assays, and nomenclature of cancer stem cells, which is technically precise without completely abolishing established terminology. We expect that this operational model will be useful for future reporting of parameters used to identify and characterize the multiple myeloma stem cells. We strongly recommend that these parameters include validated standard technologies, reproducible assays, and, most importantly, supervised prospective sampling of selected biomaterial which reflects clinical stages, disease spectrum, and therapeutic outcome. This framework is key to the characterization of the cellular architecture of multiple myeloma and its use in precision medicine.

Activation of the phospholipase C pathway by ATP is mediated exclusively through nucleotide type P2-purinoceptors in C2C12 myotubes

1. The presence of a nucleotide receptor and a discrete ATP-sensitive receptor on C2C12 myotubes has been shown by electrophysiological experiments. In this study, the ATP-sensitive receptors of C2C12 myotubes were further characterized by measuring the formation of inositol(1,4,5)trisphosphate (Ins(1,4,5)P3) and internal Ca2+. 2. The nucleotides ATP and UTP caused a concentration-dependent increase in Ins(1,4,5)P3 content with comparable time courses (EC50: ATP 33 +/- 2 microM, UTP 80 +/- 4 microM). ADP was less effective in increasing Ins(1,4,5)P3 content of the cells, while selective agonists for P1-, P2X- and P2Y-purinoceptors, adenosine, alpha,beta-methylene ATP and 2-methylthio ATP, appeared to be ineffective. 3. Under Ca(2+)-free conditions, the basal level of Ins(1,4,5)P3 was lower than in the presence of Ca2+, and the ATP- and UTP-induced formation of Ins(1,4,5)P3 was diminished. 4. The Ins(1,4,5)P3 formation induced by optimal ATP and UTP concentrations was not additive. ATP- and UTP-induced Ins(1,4,5)P3 formation showed cross-desensitization, whereas cross-desensitization was absent in responses elicited by one of the nucleotides and bradykinin. 5. The change in Ins(1,4,5)P3 content induced by effective nucleotides was inhibited by suramin. Schild plots for suramin inhibition of Ins(1,4,5)P3 formation in ATP- and UTP-stimulated myotubes showed slopes greater than unity (1.63 +/- 0.09 and 1.37 +/- 0.11, respectively). Apparent pA2 values were 4.50 +/- 0.48 and 4.41 +/- 0.63 for ATP and UTP, respectively. 6. Stimulation of the cells with ATP or UTP induced a rapid increase in intracellular Ca2+, followed by a slow decline to basal levels. Ca2+ responses reached lower maximal values and did not show the slow phase in the absence of extracellular Ca2+. The ATP and UTP-evoked increase in intracellular Ca2+ was not additive and showed cross-desensitization. Cross-desensitization was absent in myotubes stimulated with one of the nucleotides and bradykinin.7. These results show that ATP- and UTP-induced formation of Ins(1,4,5)P3, Ca2+ release from internal stores and Ca2+-influx from the extracellular space are mediated exclusively via the nucleotide type P2-purinoceptor in mouse C2C12 myotubes.

A Genome-Wide Association Study Identifies a Novel Locus for Bortezomib-Induced Peripheral Neuropathy in European Patients with Multiple Myeloma

PURPOSE

Painful peripheral neuropathy is a frequent toxicity associated with bortezomib therapy. This study aimed to identify loci that affect susceptibility to this toxicity.

EXPERIMENTAL DESIGN

A genome-wide association study (GWAS) of 370,605 SNPs was performed to identify risk variants for developing severe bortezomib-induced peripheral neuropathy (BiPN) in 469 patients with multiple myeloma who received bortezomib-dexamethasone therapy prior to autologous stem cell in randomized clinical trials of the Intergroupe Francophone du Myelome (IFM) and findings were replicated in 114 patients with multiple myeloma of the HOVON-65/GMMG-HD4 clinical trial.

RESULTS

An SNP in the PKNOX1 gene was associated with BiPN in the exploratory cohort [rs2839629; OR, 1.89, 95% confidence interval (CI), 1.45-2.44; P = 7.6 × 10(-6)] and in the replication cohort (OR, 2.04; 95% CI, = 1.11-3.33; P = 8.3 × 10(-3)). In addition, rs2839629 is in strong linkage disequilibrium (r(2) = 0.87) with rs915854, located in the intergenic region between PKNOX1 and cystathionine-ß-synthetase (CBS) Expression quantitative trait loci mapping showed that both rs2839629 and rs915854 genotypes have an impact on PKNOX1 expression in nerve tissue, whereas rs2839629 affects CBS expression in skin and blood.

CONCLUSIONS

The use of GWAS in multiple myeloma pharmacogenomics has identified a novel candidate genetic locus mapping to PKNOX1 and in the immediate vicinity of CBS at 21q22.3 associated with the severe bortezomib-induced toxicity. The proximity of these two genes involved in neurologic pain whose tissue-specific expression is modified by the two variants provides new targets for neuroprotective strategies. Clin Cancer Res; 22(17); 4350-5. ©2016 AACR.

Characterization of P2-purinoceptor mediated cyclic AMP formation in mouse C2C12 myotubes

1. The formation of adenosine 3':5'-cyclic monophosphate (cyclic AMP) and inositol(1,4,5)trisphosphate (Ins(1,4,5)P3), induced by ATP and other nucleotides was investigated in mouse C2C12 myotubes. 2. ATP (100 microM) and ATP gamma S (100 microM) caused a sustained increase in cyclic AMP content of the cells, reaching a maximum after 10 min. The cyclic AMP content reached a maximum in the presence of 100 microM ATP, followed by a decline at higher ATP concentrations. ATP-induced cyclic AMP formation was inhibited by the P2-purinoceptor antagonist, suramin. 3. Myotubes hydrolysed ATP to ADP at a rate of 9.7 +/- 1.0 nmol mg-1 protein min-1. However, further hydrolysis of ADP to AMP and adenosine was negligible. 4. The cyclic AMP formation induced by ADP (10 microM-1 mM) showed similar characteristics to that induced by ATP, but a less pronounced decline was observed than with ATP. ADP-induced cyclic AMP formation was blocked by suramin, while cyclic AMP formation elicited by adenosine (10 microM-1 mM) was insensitive to suramin. 5. The ATP analogue, alpha,beta-methylene-ATP also induced a suramin-sensitive cyclic AMP formation, while 2-methylthio-ATP and the pyrimidine, UTP, did not affect cyclic AMP levels. 6. Stimulation of the myotubes with ATP or UTP (10 microM-1 mM) caused a concentration-dependent increase in the Ins(1,4,5)P3 content of the cells. ADP (100 microM-1 mM) was less effective. Adenosine did not affect Ins(1,4,5)P3 levels. 7. Incubation of the cells with UTP (30 microM- 1 mM) inhibited the ATP- and ADP-induced cyclic AMP formation, suggesting that stimulation of the 'nucleotide' type P2-receptor inhibits P2-purinoceptor mediated cyclic AMP formation in C2C12 myotubes. In contrast, UTP (30 microM-I mM) enhanced adenosine-induced cyclic AMP formation.8. Adenosine-sensitive P1-purinoceptors activating cyclic AMP formation were found in C2C12 myotubes.Further, a novel P2-purinoceptor is postulated, sensitive to ATP, ADP and ATPgammaS, which also activates the formation of cyclic AMP in C2C12 myotubes.

α1-Adrenoceptor-mediated contraction of rat aorta is partly mediated via transactivation of the epidermal growth factor receptor

BACKGROUND AND PURPOSE

High level of plasma catecholamines is a risk factor for vascular diseases such as hypertension and atherosclerosis. Catecholamines induce hypertrophy of vascular smooth muscle through α(1) -adrenoceptors, which in cell culture involves the transactivation of epidermal growth factor receptor (EGFR). We hypothesized that EGFR transactivation was also involved in contractions of rat aorta mediated by α(1) -adrenoceptors.

EXPERIMENTAL APPROACH

Thoracic aorta was isolated from 12-14 week old male Wistar rats. In vitro aortic contractile responses to cumulative doses of phenylephrine were characterized in the absence and presence of the EGFR kinase inhibitors, AG1478 and DAPH, in intact and endothelium-denuded rings. Involvement of signal transduction pathways was investigated by using heparin and inhibitors of Src, matrix metalloproteinase (MMP), extracellular signal-regulated kinase (ERK)1/2 and phosphatidyl inositol 3-kinase (PI3K). Phosphorylation of EGFR and ERK1/2 was measured after short-term phenylephrine or EGF stimulation in aorta segments in the presence of AG1478 and the PI3K inhibitor, wortmannin.

KEY RESULTS

AG1478 and DAPH concentration dependently attenuated phenylephrine-induced contractile responses in intact or endothelium-denuded aortic rings. Inhibition of PI3K (wortmannin and LY294002) but not heparin or inhibitors of Src or MMP, prevented the effect of AG1478 on the responses to phenylephrine. Phenylephrine induced phosphorylation of EGFR, which was partially blocked by AG1478. Phenylephrine also increased phosphorylation of ERK1/2, time-dependently and was blocked by AG1478 and wortmannin.

CONCLUSIONS AND IMPLICATIONS

Contractions of rat thoracic aorta mediated by α(1) -adrenoceptors involved transactivation of EGFR, mediated via a PI3K and ERK1/2 dependent pathway.

Variation in the E2-binding domain of HPV 16 is associated with high-grade squamous intraepithelial lesions of the cervix

Human papillomaviruses (HPV) are strongly associated with cervical intraepithelial neoplasia (CIN) and invasive cancer mainly through the action of the E6 and E7 viral proteins, transcription of which is down-regulated by the E2 protein. To test the hypothesis that HPV 16 E2 variation is important in the development of high-grade squamous neoplasia of the cervix, we carried out a cross-sectional analysis of low-grade and high-grade squamous intraepithelial lesions (SILs) for specific mutations in the HPV 16 E2 gene and for E2 gene disruption in these regions. Isolates were also analysed for the HPV 16 350T-G variant. 22 of 178 low-grade SILs and 43 of 61 high-grade SILs examined, contained HPV 16. No relationship was found between the E6 350T-G variant, or the E2 hinge region 3410C-T variant, and lesion grade. However, disruption of the regions of E2 analysed was significantly more frequent in high-grade lesions, and there was a significant association between the 3684C-A variant in the E2 DNA binding domain and high-grade histology suggesting that this variant may be important in progression to high-grade intraepithelial disease.

Regulation of histamine- and UTP-induced increases in Ins(1,4,5)P3, Ins (1,3,4,5)P4 and Ca2+ by cyclic AMP in DDT1 MF-2 cells

1. Stimulation of P2U-purinoceptors with UTP or histamine H1-receptors with histamine gave rise to the formation of inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) and inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4) in DDT1 MF-2 smooth muscle cells. 2. Stimulation of P2U-purinoceptors or histamine H1-receptors caused an increase in cytoplasmic Ca2+, consisting of an initial peak, representing the release of Ca2+ from internal stores and a sustained phase representing Ca2+ influx. 3. The P2U-purinoceptor-mediated Ca(2+)-entry mechanism was more sensitive to UTP than Ca(2+)-mobilization (EC50: 3.3 microM +/- 0.4 microM vs 55.1 microM +/- 9.2 microM), in contrast to these processes activated by histamine H1-receptors (EC50: 5.8 microM +/- 0.6 microM vs 3.1 microM +/- 0.5 microM). 4. Pre-stimulation of cells with several adenosine 3':5'-cyclic monophosphate (cyclic AMP) elevating agents, reduced the histamine H1-receptor-mediated formation of Ins(1,4,5)P3 and Ins(1,3,4,5)P4. Forskolin completely inhibited Ins(1,4,5)P3 formation (IC50: 158 +/- 24 nM) whereas Ins(1,3,4,5)P4 formation was inhibited by only 45% (IC50: 173 +/- 16 nM). The P2U-purinoceptor-mediated production of these inositol phosphates was not affected by cyclic AMP. 5. Forskolin and isoprenaline reduced the histamine-induced increase in cytoplasmic Ca2+, as measured in Ca2+ containing medium and in nominally Ca(2+)-free medium but did not change the UTP-induced increase in cytoplasmic Ca2+. 6. These results clearly demonstrate that cyclic AMP differentially regulates components of the histamine induced phospholipase C signal transduction pathway. Furthermore, cyclic AMP does not affect the phospholipase C pathway activated by stimulation of P2U-purinoceptors in DDT1 MF-2 cells.

Identification of High-Risk Multiple Myeloma With a Plasma Cell Leukemia-Like Transcriptomic Profile

PURPOSE

Primary plasma cell leukemia (pPCL) is an aggressive subtype of multiple myeloma, which is distinguished from newly diagnosed multiple myeloma (NDMM) on the basis of the presence of ≥ 20% circulating tumor cells (CTCs). A molecular marker for pPCL is currently lacking, which could help identify NDMM patients with high-risk PCL-like disease, despite not having been recognized as such clinically.

METHODS

A transcriptomic classifier for PCL-like disease was bioinformatically constructed and validated by leveraging information on baseline CTC levels, tumor burden, and tumor transcriptomics from 154 patients with NDMM included in the Cassiopeia or HO143 trials and 29 patients with pPCL from the EMN12/HO129 trial. Its prognostic value was assessed in an independent cohort of 2,139 patients with NDMM from the HOVON-65/GMMG-HD4, HOVON-87/NMSG-18, EMN02/HO95, MRC-IX, Total Therapy 2, Total Therapy 3, and MMRF CoMMpass studies.

RESULTS

High CTC levels were associated with the expression of 1,700 genes, independent of tumor burden (false discovery rate < 0.05). Of these, 54 genes were selected by leave-one-out cross-validation to construct a transcriptomic classifier representing PCL-like disease. This not only demonstrated a sensitivity of 93% to identify pPCL in the validation cohort but also classified 10% of NDMM tumors as PCL-like. PCL-like MM transcriptionally and cytogenetically resembled pPCL, but presented with significantly lower CTC levels and tumor burden. Multivariate analyses in NDMM confirmed the significant prognostic value of PCL-like status in the context of Revised International Staging System stage, age, and treatment, regarding both progression-free (hazard ratio, 1.64; 95% CI, 1.30 to 2.07) and overall survival (hazard ratio, 1.89; 95% CI, 1.42 to 2.50).

CONCLUSION

pPCL was identified on the basis of a specific tumor transcriptome, which was also present in patients with high-risk NDMM, despite not being clinically leukemic. Incorporating PCL-like status into current risk models in NDMM may improve prognostic accuracy.

Calcium release from separate receptor-specific intracellular stores induced by histamine and ATP in a hamster cell line

1. The specificity of intracellular Ca2+ stores to Ca(2+)-mobilizing agonists was studied in DDT1 MF-2 vas deferens cells of the Syrian hamster. 2. Application of histamine (100 microM) or ATP (100 microM) to the DDT1 MF-2 cells caused an initial increase of intracellular Ca2+ followed by a lower phase as measured by using Indo-1 as fluorescent probe at 22 degrees C. The basal Ca2+ level (146 nM) was enhanced to 309 nM by histamine and to 379 nM by ATP. 3. A transient rise in intracellular Ca2+ lasting for about 2 min was measured in the presence of histamine or ATP in the absence of extracellular Ca2+. The basal Ca2+ level (78 nM) was increased to 128 nM by histamine and to 145 nM by ATP. 4. A transient hyperpolarization was elicited in single cells as measured with microelectrodes by both agonists under Ca(2+)-free conditions with a similar time course as the change in internal Ca2+. The hyperpolarization observed in the presence of histamine amounted to 23 mV and 31 mV with ATP. The histamine-induced responses were abolished by the H1 histaminoceptor antagonist mepyramine (10 microM) and the responses evoked by ATP were blocked by the P2 purinoceptor antagonist suramin (300 microM). 5. A second internal Ca2+ response could only be evoked under Ca(2+)-free conditions by applying a higher agonist concentration or after replenishing the intracellular stores with Ca2+ from the extracellular space. 6. A second addition of an optimal concentration (100 microM) of the agonist to the cells under Ca(2+)-free conditions did not evoke mobilization of internal Ca2+ or hyperpolarization, but resulted in a rise of the cellular inositol (1,4,5)-trisphosphate content (Ins(1,4,5)P3) as determined by a radioligand binding assay. 7. The cells responded to both agonists (100 microM) with a transient Ca2+ response if successively applied at a maximal effective concentration (100 microM) under Ca(2+)-free conditions. 8. Simultaneous stimulation of H1 histaminoceptors and P2 purinoceptors resulted in the absence of external Ca2+ in an additional increase in internal Ca2+ represented by the amplitude and area of the response and in an increased response area of the hyperpolarization.(ABSTRACT TRUNCATED AT 400 WORDS)

Different mechanisms of Ca2(+)-handling following nicotinic acetylcholine receptor stimulation, P2U-purinoceptor stimulation and K(+)-induced depolarization in C2C12 myotubes

1. The increase in intracellular CA2+ on nicotinic acetylcholine receptor (nAChR) stimulation, P2U-purinoceptor stimulation and K(+)-induced depolarization was investigated in mouse C2C12 myotubes by use of fura-2 fluorescence to characterize the intracellular organisation of Ca2+ releasing stores and Ca(2+)-entry process. 2. Stimulation of nAChRs with carbachol induced a rapid rise in internal Ca2+ (EC50 = 0.85 +/- 0.09 microM), followed by a sustained phase. The Ca2+ response evoked by carbachol (10 microM) was completely blocked by the nAChR antagonist, pancuronium (3 microM), but was not affected by the muscarinic antagonist, atropine (3 microM), or under conditions when Ca2+ entry was blocked by La3+ (50 microM) or diltiazem (10 microM). Addition of pancuronium (3 microM) during the sustained phase of the carbachol-evoked response did not affect this phase. 3. Stimulation of P2U purinoceptors with ATP (1 mM) induced a somewhat higher biphasic Ca2+ response (EC50 of the rapid phase: 8.72 +/- 0.08 microM) than with carbachol. Pretreatment with La3+ abolished the sustained phase of the ATP-induced Ca2+ response, while the response was unaffected by diltiazem or pancuronium. 4. Stimulation of the cells with high K+ (60 mM), producing the same depolarization as with carbachol (10 microM), induced a rapid monophasic Ca2+ response, insensitive to diltiazem, pancuronium or La3+. 5. Under Ca(2+)-free conditions, the sustained phase of the carbachol- and ATP-evoked responses were abolished. Pre-emptying of depolarization-sensitive stores by high K+ under Ca(2+)-free conditions did not affect the carbachol- or ATP-evoked Ca2+ mobilization and vice versa. Preincubation of the cells with ATP in the absence of extracellular Ca2+ decreased the amplitude of the subsequent carbachol-induced Ca2+ response to 11%, while in the reverse procedure the ATP-induced response was decreased to 65%. Ca2+ mobilization evoked by simultaneous addition of optimal concentrations of carbachol and ATP was increased compared to levels obtained with either agonist. 6. Preincubation with high K+ under normal conditions abolished the sustained phase of the ATP-evoked Ca2+ response. The carbachol response consisted only of the sustained phase in the presence of high K+. 7. The carbachol-induced Ca2+ response was completely abolished under low Na+/Ca(2+)-free conditions, while under low Na+ conditions only a sustained Ca2+ response was observed. The ATP- and K(+)-induced responses were changed compared to Ca(2+)-free conditions. 8. ATP (300 microM) induced the formation of Ins(1,4,5)P3 under Ca(2+)-free conditions with a comparable time course to that found for the rise in internal Ca2+. In contrast to ATP, carbachol (10 microM) did not affect Ins(1,4,5)P3 levels under Ca(2+)-free conditions. 9. It is concluded that the Ca2+ release from discrete stores of C2C12 myotubes is induced by stimulation of nAChRs, P2U-purinoceptors and by high K+. Only the P2U-purinoceptor and nAChR activated stores show considerable overlap in releasable Ca2+. Sustained Ca(2+)-entry is activated by stimulation of nAChRs and P2U-purinoceptors via separate ion-channels, which are different from the skeletal muscle nAChR-coupled cation-channel.

Genetic correlation between multiple myeloma and chronic lymphocytic leukaemia provides evidence for shared aetiology

The clustering of different types of B-cell malignancies in families raises the possibility of shared aetiology. To examine this, we performed cross-trait linkage disequilibrium (LD)-score regression of multiple myeloma (MM) and chronic lymphocytic leukaemia (CLL) genome-wide association study (GWAS) data sets, totalling 11,734 cases and 29,468 controls. A significant genetic correlation between these two B-cell malignancies was shown (Rg = 0.4, P = 0.0046). Furthermore, four of the 45 known CLL risk loci were shown to associate with MM risk and five of the 23 known MM risk loci associate with CLL risk. By integrating eQTL, Hi-C and ChIP-seq data, we show that these pleiotropic risk loci are enriched for B-cell regulatory elements and implicate B-cell developmental genes. These data identify shared biological pathways influencing the development of CLL and, MM and further our understanding of the aetiological basis of these B-cell malignancies.

P2 purinoceptor-mediated inositol phosphate formation in relation to cytoplasmic calcium in DDT1 MF-2 smooth muscle cells

The effect of P2 purinoceptor stimulation on inositol phosphate (InsP) formation in relation to the intracellular Ca2+ concentration was measured in vas deferens DDT1 MF-2 smooth muscle cells. The different [3H]myo-inositol-labelled InsP fractions were analyzed by high performance liquid chromatography and intracellular Ca2+ was determined by measuring fluorescence using Indo-1 as indicator. Stimulation with ATP (10(-4) M) resulted in an enhanced formation of inositol mono-, bis-, tris- and tetrakisphosphate (InsP1, InsP2, InsP3 and InsP4), but no changes occurred in the formation of inositol pentakis- and hexakisphosphate (InsP5 and InsP6). The putative second messenger Ins(1,3,4,5)P4 rapidly increased after addition of the agonist, reaching a maximum after about 2 min. The isomer Ins(1,4,5)P3 showed a delayed rise starting after about 2 min. The formation of Ins(1,3,4,5)P4 in the presence of ATP (2 min) was concentration-dependent, reaching a half maximal value at about 50 microM of the agonist. The intracellular Ca2+ concentration showed an initial increase after P2 purinoceptor stimulation, reaching a plateau after 2 min. Both the top of the initial phase and the plateau value of the response reached a half maximal value at an ATP concentration of about 7 microM. This Ca2+ response could be evoked repeatedly by ATP and was not affected by diltiazem (10(-5) M). In the absence of external Ca2+, the internal Ca2+ concentration increased transiently in the presence of ATP without showing the plateau phase. This response could be evoked only once under Ca2(+)-free conditions.(ABSTRACT TRUNCATED AT 250 WORDS)