Non-operative management after immune checkpoint inhibitors for early-stage, dMMR/MSI-H gastrointestinal cancers.

Surgery is a standard treatment for early-stage gastrointestinal cancers, often preceded by neoadjuvant chemo(radio)therapy or followed by adjuvant therapy. While leading to cure in a proportion of patients, it has some drawbacks such as intra/post-operative complications, mutilation and life-long functional sequelae. Further to the unprecedented efficacy data from studies of immune checkpoint inhibitors for advanced mismatch repair deficient/microsatellite instable (dMMR/MSI-H) tumours, a strong interest has recently emerged for the investigation of such agents in the neoadjuvant setting. Although limited by the exploratory design and small sample size, trials of neoadjuvant immune checkpoint inhibitors for early-stage dMMR/MSI-H gastrointestinal cancers have consistently reported complete response rates ranging from 70 % to 100 %. As a result, the question has arisen as to whether surgery is still needed or organ-preserving strategies should be offered to this especially immuno-sensitive population. In this article, we discuss the available evidence for neoadjuvant immune checkpoint inhibitors in dMMR/MSI-H gastrointestinal cancers and analyse opportunities and challenges to the implementation of non-operative management approaches in this setting.

More Than Meets the Eye: A Case of Breast Cancer Switching from Being Luminal-Androgen-Receptor-Positive to Being Hormone-Receptor-Positive.

Triple-negative breast cancer (TNBC) represents about 15% of all breast cancers and is usually characterized by aggressive clinical behavior and a poor prognosis. Four TNBC subgroups have been previously defined with different molecular profiles: (i) luminal androgen receptor (LAR), (ii) mesenchymal (MES), (iii) basal-like immunosuppressed (BLIS) and (iv) basal-like immune-activated (BLIA). Among these, LAR is characterized by the expression of the androgen receptor (AR), and exhibits genomic characteristics that resemble luminal breast cancers, with a still undefined prognosis and clinical behavior. Here, we report a case of a woman affected by recurring LAR TNBC, which underwent phenotypic changes throughout its natural history. After the initial diagnosis of LAR breast cancer, the patient experienced local recurrence with strong expression of the estrogen receptor. Due to this finding, she started treatment with a CDK4/6-inhibitor and an aromatase inhibitor, followed by oral vinorelbine, both with dismal outcomes. Then, she received everolimus and exemestane, which determined temporary disease stabilization. An extensive NGS analysis of tumor tissue showed PIK3CA and HER2 mutations. Our case is consistent with previous reports of LAR breast cancer and underlines the potential utility of re-biopsy and molecular testing in breast cancer (BC), especially in rare subtypes.

HDAC11 deficiency disrupts oncogene-induced hematopoiesis in myeloproliferative neoplasms.

Protein acetylation is an important contributor to cancer initiation. Histone deacetylase 6 (HDAC6) controls JAK2 translation and protein stability and has been implicated in JAK2-driven diseases best exemplified by myeloproliferative neoplasms (MPNs). By using novel classes of highly selective HDAC inhibitors and genetically deficient mouse models, we discovered that HDAC11 rather than HDAC6 is necessary for the proliferation and survival of oncogenic JAK2-driven MPN cells and patient samples. Notably, HDAC11 is variably expressed in primitive stem cells and is expressed largely upon lineage commitment. Although Hdac11is dispensable for normal homeostatic hematopoietic stem and progenitor cell differentiation based on chimeric bone marrow reconstitution, Hdac11 deficiency significantly reduced the abnormal megakaryocyte population, improved splenic architecture, reduced fibrosis, and increased survival in the MPLW515L-MPN mouse model during primary and secondary transplantation. Therefore, inhibitors of HDAC11 are an attractive therapy for treating patients with MPN. Although JAK2 inhibitor therapy provides substantial clinical benefit in MPN patients, the identification of alternative therapeutic targets is needed to reverse MPN pathogenesis and control malignant hematopoiesis. This study establishes HDAC11 as a unique type of target molecule that has therapeutic potential in MPN.

Progression in migraine: Role of mast cells and pro-inflammatory and anti-inflammatory cytokines.

Migraine is a common painful neurovascular disorder usually associated with several symptoms, such as photophobia, phonophobia, nausea, vomiting and inflammation, and involves immune cells. Mast cells (MCs) are immune cells derived from hematopoietic pluripotent stem cells which migrate and mature close to epithelial, blood vessels, and nerves. In almost all vascularized tissues there are MCs that produce, contain and release biologically active products including cytokines, arachidonic acid compounds, and proteases. In addition, MCs participate in innate and adaptive immune responses. Innate responses in the central nervous system (CNS) occur during neuroinflammatory phenomena, including migraine. Antigens found in the environment have a crucial role in inflammatory response, causing a broad range of diseases including migraine. They can be recognized by several innate immune cells, such as macrophages, microglia, dendritic cells and MCs, which can be activated trough Toll-like receptor (TLR) signaling. MCs reside close to primary nociceptive neurons, associate with nerves, and are capable of triggering local inflammation. MCs are involved in the pathophysiology of various tissues and organs, especially where there is an increase of angiogenesis. Activated MCs release preformed mediators include histamine, heparin, proteases (tryptase, chimase), hydrolases, cathepsin, carboxypeptidases, and peroxidase, and they also generate pro-inflammatory cytokines/chemokines. In addition, activated macrophages, microglia and MCs in the CNS release pro-inflammatory cytokines which provoke an increase of arachidonic acid product levels and lead to migraine and other neurological manifestations including fatigue, nausea, headaches and brain fog. Innate immunity and pro-inflammatory interleukin (IL)-1 cytokine family members can be inhibited by IL-37, a relatively new member of the IL-1 family. In this article, we report that some pro-inflammatory cytokines inducing migraine may be inhibited by IL-37, a natural suppressor of inflammation, and innate and acquired immunity.

Impact of mast cells in depression disorder: inhibitory effect of IL-37 (new frontiers).

The purpose of this article is to study the involvement of inflammatory mast cells (MCs) in depression which may be inhibited by IL-37. We evaluate mast cells in depression on the basis of our previous experimental data, and using the most relevant studies reported in the literature. Dysfunction of mood, feelings, and thoughts is a major risk factor for several metabolic diseases and may influence the physiology of the body leading to depression. Depression, present in mastocytosis, is an important endogenous process that promotes the activation of meningeal cell receptors through a low-grade neurogenic chronic inflammation, and MCs. Mast cells are localized along meningeal blood vessels and connective tissues, as well as between the ganglion cells and nerve fibers. They are present in the hypothalamus of mammalian brains capable of communication with nerves. MCs are classically activated by binding to IgE cross-link FcεRI high-affinity receptor leading to release a plethora of mediators responsible for the generation of inflammatory cytokines. Corticotropin-releasing hormone (CRH), produced by MCs, has been found in microglial cells where it regulates immune cells and contributes to the pathogenesis of neurodegenerative diseases including depression. Inflammatory cytokines released by MCs aggravate depression and could be partially inhibited by IL-37. A detailed understanding of the interaction between the immune system, including MCs and depression, is necessary in order to address an effective therapy which could include IL-37. As a consequence, the concepts reviewed here have treatment implications.

Discovery of novel N-hydroxy-2-arylisoindoline-4-carboxamides as potent and selective inhibitors of HDAC11.

N-Hydroxy-2-arylisoindoline-4-carboxamides are potent and selective inhibitors of HDAC11. The discovery, synthesis, and structure activity relationships of this novel series of inhibitors are reported. An advanced analog (FT895) displays promising cellular activity and pharmacokinetic properties that make it a useful tool to study the biology of HDAC11 and its potential use as a therapeutic target for oncology and inflammation indications.

Inhibition of histone deacetylase in cancer cells slows down replication forks, activates dormant origins, and induces DNA damage.

Protein acetylation is a reversible process regulated by histone deacetylases (HDAC) that is often altered in human cancers. Suberoylanilide hydroxamic acid (SAHA) is the first HDAC inhibitor to be approved for clinical use as an anticancer agent. Given that histone acetylation is a key determinant of chromatin structure, we investigated how SAHA may affect DNA replication and integrity to gain deeper insights into the basis for its anticancer activity. Nuclear replication factories were visualized with confocal immunofluorescence microscopy and single-replicon analyses were conducted by genome-wide molecular combing after pulse labeling with two thymidine analogues. We found that pharmacologic concentrations of SAHA induce replication-mediated DNA damage with activation of histone gammaH2AX. Single DNA molecule analyses indicated slowdown in replication speed along with activation of dormant replication origins in response to SAHA. Similar results were obtained using siRNA-mediated depletion of HDAC3 expression, implicating this HDAC member as a likely target in the SAHA response. Activation of dormant origins was confirmed by molecular analyses of the beta-globin locus control region. Our findings demonstrate that SAHA produces profound alterations in DNA replication that cause DNA damage, establishing a critical link between robust chromatin acetylation and DNA replication in human cancer cells.

Chk1 inhibition after replicative stress activates a double strand break response mediated by ATM and DNA-dependent protein kinase.

Checkpoint kinase 1 (Chk1) regulates cell cycle checkpoints and DNA damage repair in response to genotoxic stress. Inhibition of Chk1 is an emerging strategy for potentiating the cytotoxicity of chemotherapeutic drugs. Here, we demonstrate that AZD7762, an ATP -competitive Chk1/2 inhibitor induces gammaH2AX in gemcitabine-treated cells by altering both dynamics and stability of replication forks, allowing the firing of suppressed replication origins as measured by DNA fiber combing and causing a dramatic increase in DNA breaks as measured by comet assay. Furthermore, we identify ATM and DNA-PK, rather than ATR, as the kinases mediating gammaH2AX induction, suggesting AZD7762 converts stalled forks into double strand breaks (DSBs). Consistent with DSB formation upon fork collapse, cells deficient in DSB repair by lack of BRCA2, XRCC3 or DNA-PK were selectively more sensitive to combined AZD7762 and gemcitabine. Checkpoint abrogation by AZD7762 also caused premature mitosis in gemcitabine-treated cells arrested in G(1)/early S-phase. Prevention of premature mitotic entry via Cdk1 siRNA knockdown suppressed apoptosis. These results demonstrate that chemosensitization of gemcitabine by Chk1 inhibition results from at least three cellular events, namely, activation of origin firing, destabilization of stalled replication forks and entry of cells with damaged DNA into lethal mitosis. Additionally, the current study indicates that the combination of Chk1 inhibitor and gemcitabine may be particularly effective in targeting tumors with specific DNA repair defects.

Topoisomerase I suppresses genomic instability by preventing interference between replication and transcription.

Topoisomerase I (Top1) is a key enzyme in functioning at the interface between DNA replication, transcription and mRNA maturation. Here, we show that Top1 suppresses genomic instability in mammalian cells by preventing a conflict between transcription and DNA replication. Using DNA combing and ChIP (chromatin immunoprecipitation)-on-chip, we found that Top1-deficient cells accumulate stalled replication forks and chromosome breaks in S phase, and that breaks occur preferentially at gene-rich regions of the genome. Notably, these phenotypes were suppressed by preventing the formation of RNA-DNA hybrids (R-loops) during transcription. Moreover, these defects could be mimicked by depletion of the splicing factor ASF/SF2 (alternative splicing factor/splicing factor 2), which interacts functionally with Top1. Taken together, these data indicate that Top1 prevents replication fork collapse by suppressing the formation of R-loops in an ASF/SF2-dependent manner. We propose that interference between replication and transcription represents a major source of spontaneous replication stress, which could drive genomic instability during the early stages of tumorigenesis.

Ataxia telangiectasia mutated activation by transcription- and topoisomerase I-induced DNA double-strand breaks.

Ataxia telangiectasia mutated (ATM), the deficiency of which causes a severe neurodegenerative disease, is a crucial mediator for the DNA damage response (DDR). As neurons have high rates of transcription that require topoisomerase I (TOP1), we investigated whether TOP1 cleavage complexes (TOP1cc)-which are potent transcription-blocking lesions-also produce transcription-dependent DNA double-strand breaks (DSBs) with ATM activation. We show the induction of DSBs and DDR activation in post-mitotic primary neurons and lymphocytes treated with camptothecin, with the induction of nuclear DDR foci containing activated ATM, gamma-H2AX (phosphorylated histone H2AX), activated CHK2 (checkpoint kinase 2), MDC1 (mediator of DNA damage checkpoint 1) and 53BP1 (p53 binding protein 1). The DSB-ATM-DDR pathway was suppressed by inhibiting transcription and gamma-H2AX signals were reduced by RNase H1 transfection, which removes transcription-mediated R-loops. Thus, we propose that Top1cc produce transcription arrests with R-loop formation and generate DSBs that activate ATM in post-mitotic cells.

Quality of life, depression, and cytokine patterns in patients with chronic hepatitis C treated with antiviral therapy.

PURPOSE: To evaluate the effect of chronic hepatitis C and antiviral therapy on health-related quality of life (HRQoL), depression symptoms and cytokine patterns. METHODS: Twenty HCV+ patients treated with peginterferon plus ribavirin were enrolled in this cohort study and invited to complete SF-12 and BDI questionnaires prior to (T0) and at the end of the treatment (T1). HCV-RNA, serum levels of ALT, AST, haemoglobin, ferritin and IFN-gamma, TNF-alpha, IL-2, IL-4, IL-6 and IL-10 were evaluated at T0 and T1. The questionnaire results were correlated to biochemical and cytokine parameters. RESULTS: Two patients (1%) dropped out and 18 HCV patients composed the final sample (11 males (61.1%); mean age 42.5+/-11.9 yr; mean disease duration 9.7+/-6.9 yr). Between T0 and T1 ALT (p=0.02), AST (p=0.052) HCV-RNA (P=0.0002) and haemoglobin levels decreased (p=0.0003), whereas ferritin level increased (P=0.003). Also, at T1 all cytokine levels were augmented. Regarding depression status, at T0 10 patients (55.5%) scored above to the BDI questionnaire (suggesting clinically significant depression), whereas at T1 14 patients scored 10 or above (77.7%). At T1 the mean BDI score increased, but this difference was not significant. Regarding HRQoL, the majority of patients had T0 summary scores < or = 50. At T1 HRQoL changed and scores decreased in 66.7% of the patients. A correlation was observed between the T0 level of ferritin and the amount of change in BDI and SF-12 mental score between T0 and T1 (Spearman rho = -0.56 and +0.61, respectively) and IL-4 level at T0 and the change in BDI and SF-12 mental scores (Spearman rho = -0.49 and +0.45, respectively). CONCLUSION: BDI, SF-12, IL-4 and ferritin are good tools to predict the appearance of depressive symptoms and worsening of the quality of life in the HCV+ population.

The mammalian DNA replication elongation checkpoint: implication of Chk1 and relationship with origin firing as determined by single DNA molecule and single cell analyses.

The regulation of DNA replication initiation is well documented, for both unperturbed and damaged cells. The regulation of elongation, or fork velocity, however, has only recently been revealed with the advent of new techniques allowing us to view DNA replication at the single cell and single DNA molecule levels. Normally in S phase, the progression of replication forks and their stability are regulated by the ATR-Claspin-Chk1 pathway. We recently showed that replication fork velocity varies across the human genome in normal and cancer cells, but that the velocity of a given fork is positively correlated with the distance between origins on the same DNA fiber. (19) Accordingly, in DNA replication-deficient Bloom's syndrome cells, reduced fork velocity is associated with an increased density of replication origins. (21) Replication elongation is also regulated in response to DNA damage. In human colon carcinoma cells treated with the topoisomerase I inhibitor camptothecin, DNA replication is inhibited both at the level of initiation and at the level of elongation through a Chk1-dependent checkpoint mechanism. (10) Together, these new findings demonstrate that replication fork velocity (fork progression) is coordinated with inter-origin distance and that it can be actively slowed down by Chk1-dependent mechanisms in response to DNA damage. Thus, we propose that the intra-S phase checkpoint consist of at least three elements: (1) stabilization of damaged replication forks; (2) suppression of firing of late origins; and (3) arrests of normal ongoing forks to prevent further DNA lesions by replication of a damaged DNA template.

Expression and secretion of CXCL8 (IL-8), release of tryptase and transcription of histidine decarboxylase mRNA by anti-IgE-activated human umbilical cord blood-derived cultured mast cells.

Activation of cytokine receptors and alterations in cytokines are thought to play important roles in neuronal dysfunction and in the pathogenesis of the nervous system diseases. CXCL8 (IL-8) is a CXC chemokine with chemotactic and inflammatory properties. Chemokines control mast cell infiltration in several inflammatory diseases, including stress and neurological dysfunctions. Using isolated human umbilical cord blood-derived cultured mast cells (HUCMC) from hematopoietic stem cells CD34+, mast cells were immunologically activated with anti-IgE at concentrations of 1, 5, 10 and 20 microg/ml leading to the dose-dependent production of IL-8 (p < 0.05). The increase in IL-8 mRNA expression was also noted when the cells were treated with anti-IgE at 10 microg/ml for 6 h. Immunologically activated HUCMC provoked the generation of tryptase in a dose- and time-dependent manner. We also found increased histidine decarboxylase (HDC) expression in activated HUCMC after 6 h of incubation, a rate-limiting enzyme responsible for the generation of histamine from histidine. Taken together, these results confirm that anti-IgE-activated mast cells release inflammatory mediators including CXCL8, a CXC chemokine which regulates several biological effects of mast cells, e.g. chemoattraction, and possibly causes cell arrest.

Endogenous gamma-H2AX-ATM-Chk2 checkpoint activation in Bloom's syndrome helicase deficient cells is related to DNA replication arrested forks.

The Bloom syndrome helicase (BLM) is critical for genomic stability. A defect in BLM activity results in the cancer-predisposing Bloom syndrome (BS). Here, we report that BLM-deficient cell lines and primary fibroblasts display an endogenously activated DNA double-strand break checkpoint response with prominent levels of phosphorylated histone H2AX (gamma-H2AX), Chk2 (p(T68)Chk2), and ATM (p(S1981)ATM) colocalizing in nuclear foci. Interestingly, the mitotic fraction of gamma-H2AX foci did not seem to be higher in BLM-deficient cells, indicating that these lesions form transiently during interphase. Pulse labeling with iododeoxyuridine and immunofluorescence microscopy showed the colocalization of gamma-H2AX, ATM, and Chk2 together with replication foci. Those foci costained for Rad51, indicating homologous recombination at these replication sites. We therefore analyzed replication in BS cells using a single molecule approach on combed DNA fibers. In addition to a higher frequency of replication fork barriers, BS cells displayed a reduced average fork velocity and global reduction of interorigin distances indicative of an elevated frequency of origin firing. Because BS is one of the most penetrant cancer-predisposing hereditary diseases, it is likely that the lack of BLM engages the cells in a situation similar to precancerous tissues with replication stress. To our knowledge, this is the first report of high ATM-Chk2 kinase activation and its linkage to replication defects in a BS model.

The intra-S-phase checkpoint affects both DNA replication initiation and elongation: single-cell and -DNA fiber analyses.

To investigate the contribution of DNA replication initiation and elongation to the intra-S-phase checkpoint, we examined cells treated with the specific topoisomerase I inhibitor camptothecin. Camptothecin is a potent anticancer agent producing well-characterized replication-mediated DNA double-strand breaks through the collision of replication forks with topoisomerase I cleavage complexes. After a short dose of camptothecin in human colon carcinoma HT29 cells, DNA replication was inhibited rapidly and did not recover for several hours following drug removal. That inhibition occurred preferentially in late-S-phase, compared to early-S-phase, cells and was due to both an inhibition of initiation and elongation, as determined by pulse-labeling nucleotide incorporation in replication foci and DNA fibers. DNA replication was actively inhibited by checkpoint activation since 7-hydroxystaurosporine (UCN-01), the specific Chk1 inhibitor CHIR-124, or transfection with small interfering RNA targeting Chk1 restored both initiation and elongation. Abrogation of the checkpoint markedly enhanced camptothecin-induced DNA damage at replication sites where histone gamma-H2AX colocalized with replication foci. Together, our study demonstrates that the intra-S-phase checkpoint is exerted by Chk1 not only upon replication initiation but also upon DNA elongation.

Replication fork velocities at adjacent replication origins are coordinately modified during DNA replication in human cells.

The spatial organization of replicons into clusters is believed to be of critical importance for genome duplication in higher eukaryotes, but its functional organization still remains to be fully clarified. The coordinated activation of origins is insufficient on its own to account for a timely completion of genome duplication when interorigin distances vary significantly and fork velocities are constant. Mechanisms coordinating origin distribution with fork progression are still poorly elucidated, because of technical difficulties of visualizing the process. Taking advantage of a single molecule approach, we delineated and compared the DNA replication kinetics at the genome level in human normal primary and malignant cells. Our results show that replication forks moving from one origin, as well as from neighboring origins, tend to exhibit the same velocity, although the plasticity of the replication program allows for their adaptation to variable interorigin distances. We also found that forks that emanated from closely spaced origins tended to move slower than those associated with long replicons. Taken together, our results indicate a functional role for origin clustering in the dynamic regulation of genome duplication.

Comparison of comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry and gas chromatography-mass spectrometry for the qualitative characterisation of roasted barley by solid-phase microextraction.

Volatile compounds of roasted barley used in the production of barley coffee, the most common coffee substitute, were analysed by using solid-phase microextraction (SPME) followed by GC-MS and comprehensive GC x GC-TOF-MS, respectively. The optimised SPME extraction conditions in terms of selection of the fibre coating, extraction time and extraction temperature allowed to obtain the highest GC response, thus enhancing the identification capabilities of the developed method. As for the SPME-GC x GC-TOF-MS analysis, 64 compounds with similarity, reverse and probability values above 800, 900 and 6000, respectively, were identified, by using a polar x apolar column set combination; in contrast, GC-MS was able to identify a lower number of compounds, i.e. 40 volatiles.

Unscheduled DNA replication origin activation at inserted HPV 18 sequences in a HPV-18/MYC amplicon.

Oncogene amplification is a critical step leading to tumorigenesis, but the underlying mechanisms are still poorly understood. Despite data suggesting that DNA replication is a major source of genomic instability, little is known about replication origin usage and replication fork progression in rearranged regions. Using a single DNA molecule approach, we provide here the first study of replication kinetics on a previously characterized MYC/papillomavirus (HPV18) amplicon in a cervical cancer. Using this amplicon as a model, we investigated the role DNA replication control plays in generating amplifications in human cancers. The data reveal severely perturbed DNA replication kinetics in the amplified region when compared with other regions of the same genome. It was found that DNA replication is initiated from both genomic and viral sequences, resulting in a higher median frequency of origin firings. In addition, it was found that the higher initiation frequency was associated with an equivalent increase in the number of stalled replication forks. These observations raise the intriguing possibility that unscheduled replication origin activation at inserted HPV-18 viral DNA sequences triggers DNA amplification in this cancer cell line and the subsequent overexpression of the MYC oncogene.

Upregulation of error-prone DNA polymerases beta and kappa slows down fork progression without activating the replication checkpoint.

There is rising evidence that cancer development is associated from its earliest stages with DNA replication stress, a major source of spontaneous genomic instability. However, the origin of these replication defects has remained unclear. We have investigated the consequences of upregulating error-prone DNA polymerases (pol) beta and kappa on chromosomal DNA replication. These enzymes are misregulated in different types of cancers and induce major chromosomal instabilities when overexpressed at low levels. Here, we have used DNA combing to show that a moderate overexpression of pol beta or pol kappa is sufficient to impede replication fork progression and to promote the activation of additional replication origins. Interestingly, alterations of the normal replication program induced by excess error-prone polymerases were not detected by the replication checkpoint. We therefore propose that upregulation of error-prone DNA polymerases induces a checkpoint-blind replication stress that contributes to genomic instability and to cancer development.