Deregulated JNK signaling enhances apoptosis during hyperthermia.

PURPOSE: c-Jun N-terminal kinases (JNKs) comprise a subfamily of mitogen-activated protein kinases (MAPKs). The JNK group is known to be activated by a variety of stimuli. However, the molecular mechanism underlying heat-induced JNK activation is largely unknown. The aim of this study was to clarify how JNK activity is stimulated by heat. METHODS AND MATERIALS: The expression levels of various MAPK members in HeLa cells, with or without hyperthermia treatment, were evaluated via western blotting. The kinase activity of MAPK members was assessed through in vitro kinase assays. Cell death was assessed in the absence or presence of siRNAs targeting MAPK-related members. RESULTS: Hyperthermia decreased the levels of MAP3Ks, such as ASK1 and MLK3 which are JNK kinase kinase members, but not those of the downstream MAP2K/SEK1 and MAPK/JNK. Despite the reduced or transient phosphorylation of ASK1, MLK3, or SEK1, downstream JNK was phosphorylated in a temperature-dependent manner. In vitro kinase assays demonstrated that heat did not directly stimulate SEK1 or JNK. However, the expression levels of DUSP16, a JNK phosphatase, were decreased upon hyperthermia treatment. DUSP16 knockdown enhanced the heat-induced activation of ASK1-SEK1-JNK pathway and apoptosis. CONCLUSION: JNK was activated in a temperature-dependent manner despite reduced or transient phosphorylation of the upstream MAP3K and MAP2K. Hyperthermia-induced degradation of DUSP16 may induce activation of the ASK1-SEK1-JNK pathway and subsequent apoptosis.

Meiotic chromosome organization and its role in recombination and cancer.

Chromosomes adopt specific conformations to regulate various cellular processes. A well-documented chromosome configuration is the highly compacted chromosome structure during metaphase. More regional chromatin conformations have also been reported, including topologically associated domains encompassing mega-bases of DNA and local chromatin loops formed by kilo-bases of DNA. In this review, we discuss the changes in chromatin conformation taking place between somatic and meiotic cells, with a special focus on the establishment of a proteinaceous structure, called the chromosome axis, at the beginning of meiosis. The chromosome axis is essential to support key meiotic processes such as chromosome pairing, homologous recombination, and balanced chromosome segregation to transition from a diploid to a haploid stage. We review the role of the chromosome axis in meiotic chromatin organization and provide a detailed description of its protein composition. We also review the conserved and distinct roles between species of axis proteins in meiotic recombination, which is a major factor contributing to the creation of genetic diversity and genome evolution. Finally, we discuss situations where the chromosome axis is deregulated and evaluate the effects on genome integrity and the consequences from protein deregulation in meiocytes exposed to heat stress, and aberrant expression of genes encoding axis proteins in mammalian somatic cells associated with certain types of cancers.

Implications of the germline variants of DNA damage response genes detected by cancer precision medicine for radiological risk communication and cancer therapy decisions.

Large-scale cancer-associated gene testing is now being rapidly incorporated into clinical settings, and is leading to incidental identification of the germline variants present in cancer patients. Because many cancer susceptibility genes are related to DNA damage response and repair, the variants may reflect not only the susceptibility to cancer but also the genetically defined radiation sensitivity of the patients and their relatives. When the presence of a certain germline variant increases the risk for developing radiation toxicity or radiation-induced secondary cancers, it will greatly influence the clinical decision-making. In order to achieve optimal radiological risk communication and to select the best cancer management for a given patient based on information from gene testing, healthcare professionals including genetic counselors, risk communicators and clinicians need to increase their knowledge of the health effects of various genetic variants. While germline loss-of-function mutations in both of the alleles of the DNA damage response genes cause rare hereditary diseases characterized by extreme hypersensitivity to radiation, the health effects of the carriers who have germline variants in one allele of such genes would be a matter of debate, especially when the significance of the variants is currently unknown. In this review, we describe the clinical significance of the genetic variants of the important DNA damage response genes, including ATM and TP53, and discuss how we can apply current knowledge to the management of cancer patients and their relatives from a radiological point of view.

Clonal evolution and clinical implications of genetic abnormalities in blastic transformation of chronic myeloid leukaemia.

Blast crisis (BC) predicts dismal outcomes in patients with chronic myeloid leukaemia (CML). Although additional genetic alterations play a central role in BC, the landscape and prognostic impact of these alterations remain elusive. Here, we comprehensively investigate genetic abnormalities in 136 BC and 148 chronic phase (CP) samples obtained from 216 CML patients using exome and targeted sequencing. One or more genetic abnormalities are found in 126 (92.6%) out of the 136 BC patients, including the RUNX1-ETS2 fusion and NBEAL2 mutations. The number of genetic alterations increase during the transition from CP to BC, which is markedly suppressed by tyrosine kinase inhibitors (TKIs). The lineage of the BC and prior use of TKIs correlate with distinct molecular profiles. Notably, genetic alterations, rather than clinical variables, contribute to a better prediction of BC prognosis. In conclusion, genetic abnormalities can help predict clinical outcomes and can guide clinical decisions in CML.

Synaptonemal complex proteins modulate the level of genome integrity in cancers.

The synaptonemal complex (SC) is a proteinaceous structure that is transiently formed during meiosis to promote homologous recombination between maternal and paternal chromosomes. As this structure is required only for meiotic recombination, the proteins constituting the complex are almost undetectable in normal somatic cells, but they can be expressed under the conditions in which the transcriptional machinery is deregulated. Accumulating evidence indicates that they are epigenetically expressed in cancers of various origin. Not surprisingly, in contrast to their meiotic roles, the somatic roles of the SC proteins remain to be investigated. However, it has recently been reported that SYCP3 and SYCE2 control DNA double-strand break repair negatively and positively, respectively, suggesting that the ectopic expression of the SC proteins in somatic cells could be associated with the maintenance of genomic instability. Thus, it is highly likely that the investigation of the somatic roles of the SC proteins would improve our understanding of the mechanisms underlying tumor development.

High-throughput functional evaluation of BRCA2 variants of unknown significance.

Numerous nontruncating missense variants of the BRCA2 gene have been identified, but there is a lack of convincing evidence, such as familial data, demonstrating their clinical relevance and they thus remain unactionable. To assess the pathogenicity of variants of unknown significance (VUSs) within BRCA2, here we develop a method, the MANO-B method, for high-throughput functional evaluation utilizing BRCA2-deficient cells and poly (ADP-ribose) polymerase (PARP) inhibitors. The estimated sensitivity and specificity of this assay compared to those of the International Agency for Research on Cancer classification system is 95% and 95% (95% confidence intervals: 77-100% and 82-99%), respectively. We classify the functional impact of 186 BRCA2 VUSs with our computational pipeline, resulting in the classification of 126 variants as normal/likely normal, 23 as intermediate, and 37 as abnormal/likely abnormal. We further describe a simplified, on-demand annotation system that could be used as a companion diagnostic for PARP inhibitors in patients with unknown BRCA2 VUSs.

[A Case of Breast Cancer Complicated with Castleman's Disease].

The patient was a 57-year-old woman with Castleman's disease. The follow-up CT scans obtained during the treatment of Castleman's disease, detected a 15mm nodule in the right breast AC area, and the patient was diagnosed with breast cancer. Lymphadenopathy was noted on both sides of the axilla; however, it was considered to be due to Catsleman's disease. Mastectomy and sentinel lymph node biopsy were performed with preoperative diagnosis of cT1cN0M0, cStage Ⅰ. Rapid diagnosis of the sentinel lymph node during the operation showed a metastatic tumor measuring 3mm and axillary dissection was performed. However, no metastasis was found in the dissected lymph node, which was, therefore, considered as an enlargement due to Castleman's disease.

Prognostic factors of Erdheim-Chester disease: a nationwide survey in Japan.

Erdheim-Chester disease is a rare histiocytosis with insufficient clinical data. To clarify the clinical features and prognostic factors of Erdheim-Chester disease, we conducted a nationwide survey to collect the detailed data of 44 patients with Erdheim-Chester disease in Japan. The median age of onset of the participants was 51 (range: 23-76) years, and the median number of involved organs per patient was 4 (range: 1-11). The existence of central nervous system disease was correlated with older age (P=0.033), the presence of cardiovascular lesions (P=0.015), and an increased number of involved organs (P=0.0042). The median survival from the onset was 10.4 years, and >3.0 mg/dL C-reactive protein level at onset was associated with worse outcome (median survival, 14.6 vs. 7.4 years; P=0.0016). In a multivariate analysis, age >60 years (hazard ratio, 25.9; 95% confidence interval, 2.82-237; P=0.0040) and the presence of digestive organ involvement (hazard ratio, 4.74; 95% confidence interval, 1.05-21.4; P=0.043) were correlated with worse survival. Fourteen patients had available histological samples of Erdheim- Chester disease lesions. BRAFV600E mutation was detected in 11 patients (78%) by Sanger sequencing. A correlation between BRAF mutation status and clinical factors was not observed. Our study revealed that age and digestive organ involvement influence the outcome of Erdheim-Chester disease patients, and an inflammatory marker, such as C-reactive protein, might reflect the activity of this inflammatory myeloid neoplasm.

PI3K/mTOR pathway inhibition overcomes radioresistance via suppression of the HIF1-α/VEGF pathway in endometrial cancer.

Radiation therapy is a key therapeutic strategy for endometrial carcinomas. However, biomarkers that predict radiosensitivity and drugs to enhance this sensitivity have not yet been established. We aimed to investigate the roles of TP53 and MAPK/PI3K pathways in endometrial carcinomas and to identify appropriate radiosensitizing therapeutics. D10 values (the irradiating dose required to reduce a cell population by 90%) were determined in eight endometrial cancer cell lines with known mutational statuses for TP53, PIK3CA, and KRAS. Cells were exposed to ionizing radiation (2-6Gy) and either a dual PI3K/mTOR inhibitor (NVP-BEZ235) or a MEK inhibitor (UO126), and their radiosensitizing effects were evaluated using clonogenic assays. The effects of silencing hypoxia-inducible factor-1 α (HIF-1α) expression with small interfering RNAs (siRNAs) were evaluated following exposure to ionizing radiation (2-3Gy). D10 values ranged from 2.0 to 3.1Gy in three cell lines expressing wild-type TP53 or from 3.3 to more than 6.0Gy in five cell lines expressing mutant TP53. NVP-BEZ235, but not UO126, significantly improved radiosensitivity through the suppression of HIF-1α/vascular endothelial growth factor-A expression. HIF-1α silencing significantly increased the induction of the sub-G1 population by ionizing radiation. Our study data suggest that TP53 mutation and PI3K pathway activation enhances radioresistance in endometrial carcinomas and that targeting the PI3K/mTOR or HIF-1α pathways could improve radiosensitivity.

Anti-tumor activity of olaparib, a poly (ADP-ribose) polymerase (PARP) inhibitor, in cultured endometrial carcinoma cells.

BACKGROUND: PTEN inactivation is the most frequent genetic aberration in endometrial cancer. One of the phosphatase-independent roles of PTEN is associated with homologous recombination (HR) in nucleus. Poly (ADP-ribose) polymerase (PARP) plays key roles in the repair of DNA single-strand breaks, and a PARP inhibitor induces synthetic lethality in cancer cells with HR deficiency. We examined the anti-tumor activity of olaparib, a PARP inhibitor, and its correlation between the sensitivity and status of PTEN in endometrial cancer cell lines. METHODS: The response to olaparib was evaluated using a clonogenic assay with SF50 values (concentration to inhibit cell survival to 50%) in 16 endometrial cancer cell lines. The effects of PTEN on the sensitivity to olaparib and ionizing radiation (IR) exposure were compared between parental HEC-6 (PTEN-null) and HEC-6 PTEN + (stably expressing wild-type PTEN) cells by clonogenic assay, foci formation of RAD51 and γH2AX, and induction of cleaved PARP. The effects of siRNA to PTEN were analyzed in cells with wild-type PTEN. RESULTS: The SF50 values were 100 nM or less in four (25%: sensitive) cell lines; whereas, SF50 values were 1,000 nM or more in four (25%: resistant) cell lines. PTEN mutations were not associated with sensitivity to olaparib (Mutant [n = 12]: 746 ± 838 nM; Wild-type [n = 4]: 215 ± 85 nM, p = 0.26 by Student's t test). RAD51 expression was observed broadly and was not associated with PTEN status in the 16 cell lines. The number of colonies in the clonogenic assay, the foci formation of RAD51 and γH2AX, and the induction of apoptosis were not affected by PTEN introduction in the HEC-6 PTEN + cells. The expression level of nuclear PTEN was not elevated within 24 h following IR in the HEC-6-PTEN + cells. In addition, knocking down PTEN by siRNA did not alter the sensitivity to olaparib in 2 cell lines with wild-type PTEN. CONCLUSIONS: Our results suggest that olaparib, a PARP inhibitor, is effective on certain endometrial cancer cell lines. Inactivation of PTEN might not affect the DNA repair function. Predictive biomarkers are warranted to utilize olaparib in endometrial cancer.

Targeting DNA damage response in cancer therapy.

Cancer chemotherapy and radiotherapy are designed to kill cancer cells mostly by inducing DNA damage. DNA damage is normally recognized and repaired by the intrinsic DNA damage response machinery. If the damaged lesions are successfully repaired, the cells will survive. In order to specifically and effectively kill cancer cells by therapies that induce DNA damage, it is important to take advantage of specific abnormalities in the DNA damage response machinery that are present in cancer cells but not in normal cells. Such properties of cancer cells can provide biomarkers or targets for sensitization. For example, defects or upregulation of the specific pathways that recognize or repair specific types of DNA damage can serve as biomarkers of favorable or poor response to therapies that induce such types of DNA damage. Inhibition of a DNA damage response pathway may enhance the therapeutic effects in combination with the DNA-damaging agents. Moreover, it may also be useful as a monotherapy when it achieves synthetic lethality, in which inhibition of a complementary DNA damage response pathway selectively kills cancer cells that have a defect in a particular DNA repair pathway. The most striking application of this strategy is the treatment of cancers deficient in homologous recombination by poly(ADP-ribose) polymerase inhibitors. In this review, we describe the impact of targeting the cancer-specific aberrations in the DNA damage response by explaining how these treatment strategies are currently being evaluated in preclinical or clinical trials.

Synaptonemal complex protein SYCP3 impairs mitotic recombination by interfering with BRCA2.

The meiosis-specific synaptonemal complex protein SYCP3 has been reported to be aberrantly expressed in tumours. However, in contrast to its well-defined function in meiosis, its possible role in mitotic cells is entirely unknown. Here, we show that SYCP3 is expressed in a range of primary tumours and that it impairs chromosomal integrity in mitotic cells. Expression of SYCP3 inhibits the homologous recombination (HR) pathway mediated by RAD51, inducing hypersensitivity to DNA-damaging agents such as a poly(ADP-ribose) polymerase (PARP) inhibitor and chromosomal instability. SYCP3 forms a complex with BRCA2 and inhibits its role in HR. These findings highlight a new mechanism for chromosomal instability in cancer and extend the range of PARP-inhibitor sensitive tumours to those expressing SYCP3.

[Pancreatoduodenectomy for locally advanced ascending colon cancer after neoadjuvant chemotherapy (mFOLFOX6)].

A 69-year-old man was referred to our hospital with the chief complaint of a palpable abdominal mass. Computed tomography and colonofiberscopy revealed that a large type 2 ascending colon cancer had invaded the duodenum and pancreas. To down-size the tumor, chemotherapy was planned and a FOLFOX regimen was effective; we therefore decided to perform a radical operation. The patient is still alive and disease-free 1 year and 8 months after the surgery.

Recombination activator function of the novel RAD51- and RAD51B-binding protein, human EVL.

The RAD51 protein is a central player in homologous recombinational repair. The RAD51B protein is one of five RAD51 paralogs that function in the homologous recombinational repair pathway in higher eukaryotes. In the present study, we found that the human EVL (Ena/Vasp-like) protein, which is suggested to be involved in actin-remodeling processes, unexpectedly binds to the RAD51 and RAD51B proteins and stimulates the RAD51-mediated homologous pairing and strand exchange. The EVL knockdown cells impaired RAD51 assembly onto damaged DNA after ionizing radiation or mitomycin C treatment. The EVL protein alone promotes single-stranded DNA annealing, and the recombination activities of the EVL protein are further enhanced by the RAD51B protein. The expression of the EVL protein is not ubiquitous, but it is significantly expressed in breast cancer-derived MCF7 cells. These results suggest that the EVL protein is a novel recombination factor that may be required for repairing specific DNA lesions, and that may cause tumor malignancy by its inappropriate expression.

Functional evidence for Eme1 as a marker of cisplatin resistance.

The ability to predict cisplatin sensitivity in tumors has been expected to greatly improve the outcome of cancer therapy, because the drug is frequently used in a variety of tumors. Although ERCC1 and other repair proteins have been investigated as markers of cisplatin resistance, reliable markers are still needed. Here, we demonstrate that Eme1 levels can predict cisplatin sensitivity more accurately than ERCC1 or Rad51 levels in a variety of human cancer cell lines. Eme1 forms a heterodimeric protein complex with Mus81 and functions as a structure-specific endonuclease. Haploinsufficiency of Eme1 led to hypersensitivity to cisplatin in the colon cancer cell line HCT116. On the basis of this finding, we examined the relationships between levels of proteins involved in the repair of interstrand cross-links and cisplatin sensitivity in human tumor cell lines with a variety of origins. Although ERCC1, Rad51 and Mus81 levels correlated with sensitivity to some extent, the clearest correlation was observed with Eme1. Tumors with low Eme1 levels were more sensitive to the drug than tumors with high levels. This suggests that the measurement of Eme1 in tumors may be more informative for cisplatin-based chemotherapy than that of the currently available markers.

Herpes simplex encephalitis and subsequent cytomegalovirus encephalitis after chemoradiotherapy for central nervous system lymphoma: a case report and literature review.

Neurological complications during the treatment of hematological malignancies have a wide range of causes. Treatment-related leukoencephalopathy has been recognized as a major complication of combined chemotherapy and radiotherapy for central nervous system (CNS) lymphoma, and can complicate the diagnosis of CNS infection. Herein, we present a patient with diffuse large B-cell lymphoma who developed herpes simplex encephalitis (HSE) and subsequent cytomegalovirus encephalitis after chemoradiotherapy for CNS relapse. Although cerebrospinal fluid examination (CSF) showed no significant pleocytosis, brain magnetic resonance imaging and polymerase chain reaction analysis of the CSF were useful in the diagnosis. With a review of the literature on the association between HSE and radiotherapy for CNS malignancies, our case suggests that an awareness of viral encephalitis is important in the differential diagnosis of acute neurologic disturbance during chemoradiotherapy for CNS lymphoma.

Clinical features of late cytomegalovirus infection after hematopoietic stem cell transplantation.

Late cytomegalovirus (CMV) disease beyond day 100 after hematopoietic stem cell transplantation (HSCT) has become an increasing problem after the introduction of preemptive ganciclovir (GCV) administration. To clarify the risk factors and outcome for late CMV reactivation and disease, we retrospectively analyzed the records of 101 Japanese adult patients who underwent allogeneic HSCT between 1998 and 2005 at our hospital. Fifty-one developed late positive CMV antigenemia, with a cumulative incidence of 53%. Recipient CMV seropositivity, the use of alemtuzumab, chronic GVHD, and high-dose steroids were significantly associated with late positive antigenemia. Eight patients developed late CMV disease, with a cumulative incidence of 8%, including retinitis and gastrointestinal disease. None progressed to a fatal disease. The use of alemtuzumab was identified as an independent significant risk factor for late CMV disease, although it was not associated with increased non-relapse mortality. Among the 51 patients with late positive antigenemia, 28 had consistently less than three positive cells, 25 of whom showed negative conversion without antiviral agents. In conclusion, late CMV antigenemia appeared to develop frequently, especially in patients with profound immune suppression; however, a fatal outcome could be prevented by optimal preemptive therapy. Low-level antigenemia may not require antiviral treatments.

Long-term ultra-low-dose acyclovir against varicella-zoster virus reactivation after allogeneic hematopoietic stem cell transplantation.

To evaluate the efficacy of long-term prophylaxis with ultra-low-dose acyclovir against varicella-zoster virus (VZV) reactivation, we analyzed the records of 242 Japanese adult patients who underwent allogeneic hematopoietic stem cell transplantation for the first time from 1995 to 2006 at our hospital. We started long-term oral acyclovir at 200 mg/day in July 2001. Acyclovir was continued until the end of immunosuppressive therapy and at least 1 year after transplantation. Sixty-six patients developed VZV reactivation at a median of 248 days after HSCT, with a cumulative incidence of 34.7%. Only one breakthrough reactivation occurred during long-term acyclovir, which responded well to therapeutic dose of valacyclovir. The use of long-term acyclovir was the only independent determinant that significantly decreased the overall incidence of VZV reactivation (20% vs. 50%, P < 0.0001). With this prophylaxis, visceral dissemination and serious complications other than post-herpetic neuralgia was completely eliminated, and thereby need for hospitalization was significantly reduced (21% vs. 71%, P = 0.0034). Fifteen of the 57 patients who discontinued acyclovir developed VZV reactivation, with a cumulative incidence of 32.1%. VZV reactivation following discontinuation tended to occur in patients who were receiving immunosuppressive therapy at the cessation of acyclovir. These findings suggested that long-term prophylaxis of ultra-low-dose acyclovir resulted in a successful prevention of severe VZV-related symptoms and death, with a significantly decreased overall incidence of VZV reactivation. Prolongation of prophylactic acyclovir on profound immunosuppression might be important for thorough suppression of VZV reactivation.

False-positive Aspergillus galactomannan antigenaemia after haematopoietic stem cell transplantation.

OBJECTIVES: Although Aspergillus galactomannan (GM) antigen detection is widely applied in the diagnosis of invasive aspergillosis (IA), false-positive reactions with fungus-derived antibiotics, other fungal genera or the passage of dietary GM through injured mucosa are a matter of concern. The aim of this study was to investigate the cumulative incidence and risk factors for false-positive GM antigenaemia. PATIENTS AND METHODS: The records of 157 adult allogeneic haematopoietic stem cell transplantation (HSCT) recipients were retrospectively analysed. Episodes of positive GM antigenaemia, defined as two consecutive GM results with an optical density index above 0.6, were classified into true, false and inconclusive GM antigenaemia by reviewing the clinical course. RESULTS: Twenty-five patients developed proven or probable IA with a 1 year cumulative incidence of 12.9%, whereas 50 experienced positive GM antigenaemia with an incidence of 32.2%. Among the total 58 positive episodes of the 50 patients, 29 were considered false-positive. The positive predictive value (PPV) was lower during the first 100 days than beyond 100 days after HSCT (37.5% versus 58.8%). Gastrointestinal chronic graft-versus-host disease (GVHD) was identified as the only independent significant factor for the increased incidence of false-positive GM antigenaemia (PPV 0% versus 66.7%, P = 0.02). CONCLUSIONS: GM antigen results must be considered cautiously in conjunction with other diagnostic procedures including computed tomography scans, especially during the first 100 days after HSCT and in patients with gastrointestinal chronic GVHD.