Clinical Impact of New Treatment Strategies for HER2-Positive Metastatic Breast Cancer Patients with Resistance to Classical Anti-HER Therapies

HER2-positive breast cancer accounts for 15-20% of all breast cancer cases. This subtype is characterized by an aggressive behavior and poor prognosis. Anti-HER2 therapies have considerably improved the natural course of the disease. Despite this, relapse still occurs in around 20% of patients due to primary or acquired treatment resistance, and metastasis remains an incurable disease. This article reviews the main mechanisms underlying resistance to anti-HER2 treatments, focusing on newer HER2-targeted therapies. The progress in anti-HER2 drugs includes the development of novel antibody-drug conjugates with improvements in the conjugation process and novel linkers and payloads. Moreover, trastuzumab deruxtecan has enhanced the efficacy of trastuzumab emtansine, and the new drug trastuzumab duocarmazine is currently undergoing clinical trials to assess its effect. The combination of anti-HER2 agents with other drugs is also being evaluated. The addition of immunotherapy checkpoint inhibitors shows some benefit in a subset of patients, indicating the need for useful biomarkers to properly stratify patients. Besides, CDK4/6 and tyrosine kinase inhibitors are also included in the design of new treatment strategies. Lapitinib, neratinib and tucatinib have been approved for HER2-positive metastasis patients, however clinical trials are currently ongoing to optimize combined strategies, to reduce toxicity, and to better define the useful setting. Clinical research should be strengthened along with the discovery and validation of new biomarkers, as well as a deeper understanding of drug resistance and action mechanisms.

Nodal positivity and systemic therapy among patients with clinical T1-T2N0 human epidermal growth factor receptor-positive breast cancer: Results from two international cohorts

BACKGROUND

The optimal treatment strategy for patients with small human epidermal growth factor receptor 2 (HER2)-positive tumors is based on nodal status. The authors' objective was to evaluate pathologic nodal disease (pathologic lymph node-positive [pN-positive] and pathologic lymph node-positive after preoperative systemic therapy [ypN-positive]) rates in patients who had clinical T1-T2 (cT1-cT2)N0M0, HER2-positive breast cancer treated with upfront surgery or neoadjuvant chemotherapy (NAC).

METHODS

Two databases were queried for patients who had cT1-cT2N0M0, HER2-positive breast cancer: (1) the Dana-Farber Brigham Cancer Center (DF/BCC) from February 2015 to October 2020 and (2) the Hospital Clinic of Barcelona and the Hospital Clinico of Valencia (HCB/HCV) from January 2012 to September 2021. The pN-positive/ypN-positive and axillary lymph node dissection (ALND) rates were compared between patients who underwent upfront surgery versus those who received NAC.

RESULTS

Among 579 patients from the DF/BCC database, 368 underwent upfront surgery, and 211 received NAC; the rates of nodal positivity were 19.8% and 12.8%, respectively (p = .021). The pN-positive rates increased by tumor size (p < .001), reaching 25% for those with cT1c tumors. The ypN-positive rates did not correlate with tumor size. NAC was associated with decreased nodal positivity (odds ratio, 0.411; 95% confidence interval, 0.202-0.838), but the ALND rates were similar (22 of 368 patients [6.0%] who underwent upfront surgery vs. 18 of 211 patients [8.5%] who received NAC; p = .173). Among 292 patients from the HCB/HCV database, 119 underwent upfront surgery, and 173 received NAC; the rates of nodal positivity were 21% and 10.4%, respectively (p = .012). The pN-positive rates increased with tumor size (p = .011). The ALND rates were equivalent by treatment strategy (23 of 119 patients [19.3%] who underwent upfront surgery vs. 24 of 173 patients [13.9%] who received NAC; p = .213).

CONCLUSIONS

Among patients who had cT1-cT2N0M0, HER2-positive breast cancer, approximately 20% who underwent upfront surgery were pN-positive, and the rate reached 25% for those with cT1c tumors. Given the opportunity for tailored therapy among lymph node-positive, HER2-positive patients, these data provide rationale for future analyses investigating the utility of routine axillary imaging in patients with HER2-positive breast cancer.

The impact of SWI/SNF and NuRD inactivation on gene expression is tightly coupled with levels of RNA polymerase II occupancy at promoters

SWI/SNF and NuRD are protein complexes that antagonistically regulate DNA accessibility. However, repression of their activities often leads to unanticipated changes in target gene expression (paradoxical), highlighting our incomplete understanding of their activities. Here we show that SWI/SNF and NuRD are in a tug-of-war to regulate PRC2 occupancy at lowly expressed and bivalent genes in mouse embryonic stem cells (mESCs). In contrast, at promoters of average or highly expressed genes, SWI/SNF and NuRD antagonistically modulate RNA polymerase II (Pol II) release kinetics, arguably owing to accompanying alterations in H3.3 and H2A.Z levels at promoter-flanking nucleosomes, leading to paradoxical changes in gene expression. Owing to this mechanism, the relative activities of the two remodelers potentiate gene promoters toward Pol II-dependent open or PRC2-dependent closed chromatin states. Our results highlight RNA Pol II occupancy as the key parameter in determining the direction of gene expression changes in response to SWI/SNF and NuRD inactivation at gene promoters in mESCs.

Role of SALL4 in HER2+ Breast Cancer Progression: Regulating PI3K/AKT Pathway

Treatment for the HER2+ breast cancer subtype is still unsatisfactory, despite breakthroughs in research. The discovery of various new molecular mechanisms of transcription factors may help to make treatment regimens more effective. The transcription factor SALL4 has been related to aggressiveness and resistance therapy in cancer. Its molecular mechanisms and involvement in various signaling pathways are unknown in the HER2+ breast cancer subtype. In this study, we have evaluated the implication of SALL4 in the HER2+ subtype through its expression in patients' samples and gain and loss of function in HER2+ cell lines. We found higher SALL4 expression in breast cancer tissues compared to healthy tissue. Interestingly, high SALL4 expression was associated with disease relapse and poor patient survival. In HER2+ cell lines, transient overexpression of SALL4 modulates PI3K/AKT signaling through regulating PTEN expression and BCL2, which increases cell survival and proliferation while reducing the efficacy of trastuzumab. SALL4 has also been observed to regulate the epithelial-mesenchymal transition and stemness features. SALL4 overexpression significantly reduced the epithelial markers E-cadherin, while it increased the mesenchymal markers β-catenin, vimentin and fibronectin. Furthermore, it has been also observed an increased expression of MYC, an essential transcription factor for regulating epithelial-mesenchymal transition and/or cancer stem cells. Our study demonstrates, for the first time, the importance of SALL4 in the HER2+ subtype and partial regulation of trastuzumab sensitivity. It provides a viable molecular mechanism-driven therapeutic strategy for an important subset of HER2-overexpressing patients whose malignancies are mediated by SALL4 expression.

Immunological Landscape of HER-2 Positive Breast Cancer

Understanding the biological aspects of immune response in HER2+ breast cancer is crucial to implementing new treatment strategies in these patients. It is well known that anti-HER2 therapy has improved survival in this population, yet a substantial percentage may relapse, creating a need within the scientific community to uncover resistance mechanisms and determine how to overcome them. This systematic review indicates the immunological mechanisms through which trastuzumab and other agents target cancer cells, also outlining the main trials studying immune checkpoint blockade. Finally, we report on anti-HER2 vaccines and include a figure exemplifying their mechanisms of action.

Transcription factor-driven coordination of cell cycle exit and lineage-specification in vivo during granulocytic differentiation : In memoriam Professor Niels Borregaard

Differentiation of multipotent stem cells into mature cells is fundamental for development and homeostasis of mammalian tissues, and requires the coordinated induction of lineage-specific transcriptional programs and cell cycle withdrawal. To understand the underlying regulatory mechanisms of this fundamental process, we investigated how the tissue-specific transcription factors, CEBPA and CEBPE, coordinate cell cycle exit and lineage-specification in vivo during granulocytic differentiation. We demonstrate that CEBPA promotes lineage-specification by launching an enhancer-primed differentiation program and direct activation of CEBPE expression. Subsequently, CEBPE confers promoter-driven cell cycle exit by sequential repression of MYC target gene expression at the G1/S transition and E2F-meditated G2/M gene expression, as well as by the up-regulation of Cdk1/2/4 inhibitors. Following cell cycle exit, CEBPE unleashes the CEBPA-primed differentiation program to generate mature granulocytes. These findings highlight how tissue-specific transcription factors coordinate cell cycle exit with differentiation through the use of distinct gene regulatory elements.

Here the authors show that differentiation of haematopoietic stem cells into mature blood cells is primed by cell type-specific transcription factors at the enhancer level during early differentiation, before they confere promoter-driven growth arrest, and activate post-mitotic terminal differentiation.

Oral Selective Estrogen Receptor Degraders (SERDs) as a Novel Breast Cancer Therapy: Present and Future from a Clinical Perspective

Estrogen receptor-positive (ER+) is the most common subtype of breast cancer. Endocrine therapy is the fundamental treatment against this entity, by directly or indirectly modifying estrogen production. Recent advances in novel compounds, such as cyclin-dependent kinase 4/6 inhibitors (CDK4/6i), or phosphoinositide 3-kinase (PI3K) inhibitors have improved progression-free survival and overall survival in these patients. However, some patients still develop endocrine resistance after or during endocrine treatment. Different underlying mechanisms have been identified as responsible for endocrine treatment resistance, where ESR1 gene mutations are one of the most studied, outstanding from others such as somatic alterations, microenvironment involvement and epigenetic changes. In this scenario, selective estrogen receptor degraders/downregulators (SERD) are one of the weapons currently in research and development against aromatase inhibitor- or tamoxifen-resistance. The first SERD to be developed and approved for ER+ breast cancer was fulvestrant, demonstrating also interesting activity in ESR1 mutated patients in the second line treatment setting. Recent investigational advances have allowed the development of new oral bioavailable SERDs. This review describes the evolution and ongoing studies in SERDs and new molecules against ER, with the hope that these novel drugs may improve our patients’ future landscape.

A KMT2A-AFF1 gene regulatory network highlights the role of core transcription factors and reveals the regulatory logic of key downstream target genes

Regulatory interactions mediated by transcription factors (TFs) make up complex networks that control cellular behavior. Fully understanding these gene regulatory networks (GRNs) offers greater insight into the consequences of disease-causing perturbations than can be achieved by studying single TF binding events in isolation. Chromosomal translocations of the lysine methyltransferase 2A (KMT2A) gene produce KMT2A fusion proteins such as KMT2A-AFF1 (previously MLL-AF4), causing poor prognosis acute lymphoblastic leukemias (ALLs) that sometimes relapse as acute myeloid leukemias (AMLs). KMT2A-AFF1 drives leukemogenesis through direct binding and inducing the aberrant overexpression of key genes, such as the anti-apoptotic factor BCL2 and the proto-oncogene MYC However, studying direct binding alone does not incorporate possible network-generated regulatory outputs, including the indirect induction of gene repression. To better understand the KMT2A-AFF1-driven regulatory landscape, we integrated ChIP-seq, patient RNA-seq, and CRISPR essentiality screens to generate a model GRN. This GRN identified several key transcription factors such as RUNX1 that regulate target genes downstream of KMT2A-AFF1 using feed-forward loop (FFL) and cascade motifs. A core set of nodes are present in both ALL and AML, and CRISPR screening revealed several factors that help mediate response to the drug venetoclax. Using our GRN, we then identified a KMT2A-AFF1:RUNX1 cascade that represses CASP9, as well as KMT2A-AFF1-driven FFLs that regulate BCL2 and MYC through combinatorial TF activity. This illustrates how our GRN can be used to better connect KMT2A-AFF1 behavior to downstream pathways that contribute to leukemogenesis, and potentially predict shifts in gene expression that mediate drug response.

BET inhibition disrupts transcription but retains enhancer-promoter contact

Enhancers are DNA sequences that enable complex temporal and tissue-specific regulation of genes in higher eukaryotes. Although it is not entirely clear how enhancer-promoter interactions can increase gene expression, this proximity has been observed in multiple systems at multiple loci and is thought to be essential for the maintenance of gene expression. Bromodomain and Extra-Terminal domain (BET) and Mediator proteins have been shown capable of forming phase condensates and are thought to be essential for super-enhancer function. Here, we show that targeting of cells with inhibitors of BET proteins or pharmacological degradation of BET protein Bromodomain-containing protein 4 (BRD4) has a strong impact on transcription but very little impact on enhancer-promoter interactions. Dissolving phase condensates reduces BRD4 and Mediator binding at enhancers and can also strongly affect gene transcription, without disrupting enhancer-promoter interactions. These results suggest that activation of transcription and maintenance of enhancer-promoter interactions are separable events. Our findings further indicate that enhancer-promoter interactions are not dependent on high levels of BRD4 and Mediator, and are likely maintained by a complex set of factors including additional activator complexes and, at some sites, CTCF and cohesin.

The basic helix-loop-helix transcription factor SHARP1 is an oncogenic driver in MLL-AF6 acute myelogenous leukemia

Acute Myeloid Leukemia (AML) with MLL gene rearrangements demonstrate unique gene expression profiles driven by MLL-fusion proteins. Here, we identify the circadian clock transcription factor SHARP1 as a novel oncogenic target in MLL-AF6 AML, which has the worst prognosis among all subtypes of MLL-rearranged AMLs. SHARP1 is expressed solely in MLL-AF6 AML, and its expression is regulated directly by MLL-AF6/DOT1L. Suppression of SHARP1 induces robust apoptosis of human MLL-AF6 AML cells. Genetic deletion in mice delays the development of leukemia and attenuated leukemia-initiating potential, while sparing normal hematopoiesis. Mechanistically, SHARP1 binds to transcriptionally active chromatin across the genome and activates genes critical for cell survival as well as key oncogenic targets of MLL-AF6. Our findings demonstrate the unique oncogenic role for SHARP1 in MLL-AF6 AML.

Gene fusions involving MLL and different partner genes define unique subgroups of acute myelogenous leukemia, but the mechanisms underlying specific subgroups are not fully clear. Here the authors elucidate the mechanisms of MLL-AF6 induced transformation, providing a distinct pathway that involves SHARP1 as a critical target.

In situ functional dissection of RNA cis-regulatory elements by multiplex CRISPR-Cas9 genome engineering

RNA regulatory elements (RREs) are an important yet relatively under-explored facet of gene regulation. Deciphering the prevalence and functional impact of this post-transcriptional control layer requires technologies for disrupting RREs without perturbing cellular homeostasis. Here we describe genome-engineering based evaluation of RNA regulatory element activity (GenERA), a clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 platform for in situ high-content functional analysis of RREs. We use GenERA to survey the entire regulatory landscape of a 3′UTR, and apply it in a multiplex fashion to analyse combinatorial interactions between sets of miRNA response elements (MREs), providing strong evidence for cooperative activity. We also employ this technology to probe the functionality of an entire MRE network under cellular homeostasis, and show that high-resolution analysis of the GenERA dataset can be used to extract functional features of MREs. This study provides a genome editing-based multiplex strategy for direct functional interrogation of RNA cis-regulatory elements in a native cellular environment.

RNA regulatory elements (RREs) are important post-transcriptional control features but studying them requires disrupting their activity without disturbing cellular homeostasis. Here the authors present GenERA, a CRISPR-Cas9 screening platform of in situ analysis of native RREs.

MLL-AF4 Spreading Identifies Binding Sites that Are Distinct from Super-Enhancers and that Govern Sensitivity to DOT1L Inhibition in Leukemia

Understanding the underlying molecular mechanisms of defined cancers is crucial for effective personalized therapies. Translocations of the mixed-lineage leukemia (MLL) gene produce fusion proteins such as MLL-AF4 that disrupt epigenetic pathways and cause poor-prognosis leukemias. Here, we find that at a subset of gene targets, MLL-AF4 binding spreads into the gene body and is associated with the spreading of Menin binding, increased transcription, increased H3K79 methylation (H3K79me2/3), a disruption of normal H3K36me3 patterns, and unmethylated CpG regions in the gene body. Compared to other H3K79me2/3 marked genes, MLL-AF4 spreading gene expression is downregulated by inhibitors of the H3K79 methyltransferase DOT1L. This sensitivity mediates synergistic interactions with additional targeted drug treatments. Therefore, epigenetic spreading and enhanced susceptibility to epidrugs provides a potential marker for better understanding combination therapies in humans.

•

MLL-AF4 binding requires an unmethylated CpG (uCpG) island and Menin

•

MLL-AF4 and Menin can spread into the gene body of some targets

•

Spreading targets are highly transcribed and have an aberrant chromatin signature

•

Spreading of MLL-AF4 is a predictor of sensitivity to DOT1L inhibitors

MLL-AF4 binds directly to a BCL-2 specific enhancer and modulates H3K27 acetylation

Survival rates for children and adults carrying mutations in the Mixed Lineage Leukemia (MLL) gene continue to have a very poor prognosis. The most common MLL mutation in acute lymphoblastic leukemia is the t(4;11)(q21;q23) chromosome translocation that fuses MLL in-frame with the AF4 gene producing MLL-AF4 and AF4-MLL fusion proteins. Previously, we found that MLL-AF4 binds to the BCL-2 gene and directly activates it through DOT1L recruitment and increased H3K79me2/3 levels. In the study described here, we performed a detailed analysis of MLL-AF4 regulation of the entire BCL-2 family. By measuring nascent RNA production in MLL-AF4 knockdowns, we found that of all the BCL-2 family genes, MLL-AF4 directly controls the active transcription of both BCL-2 and MCL-1 and also represses BIM via binding of the polycomb group repressor 1 (PRC1) complex component CBX8. We further analyzed MLL-AF4 activation of the BCL-2 gene using Capture-C and identified a BCL-2-specific enhancer, consisting of two clusters of H3K27Ac at the 3' end of the gene. Loss of MLL-AF4 activity results in a reduction of H3K79me3 levels in the gene body and H3K27Ac levels at the 3' BCL-2 enhancer, revealing a novel regulatory link between these two histone marks and MLL-AF4-mediated activation of BCL-2.

Measuring Emotional Intelligence

The purposes of this study were (a) to develop a measure of emotional intelligence, the Emotional Intelligence Inventory and (b) to find the underlying dimensions of the inventory by testing 111 high school students at a bilingual college preparatory school. The inventory has 45 items. After excluding the four weakest items, the reliability coefficient α was .83. Subsequently, 319 junior and senior high school students at the same school were administered the 41 items. The reliability coefficient was .81. A maximum likelihood factor analysis with a varimax rotation yielded four factors of empathy, utilization of feelings, handling relationships, and self-control. Psychometric properties were sound, and the revised Emotional Intelligence Inventory can be recommended for use in the investigation of emotional intelligence.

Fosfomycin: Uses and potentialities in veterinary medicine

Fosfomycin (FOS) is a natural bactericidal broad-spectrum antibiotic which acts on proliferating bacteria by inhibiting cell wall and early murein/peptidoglycan synthesis. Bactericidal activity is evident against Gram positive and Gram negative bacteria and can also act synergistically with other antibiotics. Bacterial resistance to FOS may be natural or acquired. Other properties of this drug include inhibition of bacterial adhesion to epithelial cells, exopolysaccharide biofilm penetration, immunomodulatory effect, phagocytosis promotion and protection against the nephrotoxicity caused by other drugs. FOS has chemical characteristics not typically observed in organic phosphoric compounds and its molecular weight is almost the lowest of all the antimicrobials. It tends to form salts easily due to its acidic nature (disodium salt, for intravenous (IV), intramuscular (IM) and subcutaneous (SC) administration; calcium and trometamol salt: for oral (PO) administration). FOS has a very low protein binding (<0.5%) which, along with its low molecular weight and water solubility, contributes to its good diffusion into fluids (cerebrospinal fluid, aqueous and vitreous humor, interstitial fluid) and tissues (placenta, bone, muscle, liver, kidney and skin/fat). In all species, important differences in the bioavailability have been found after administration in relation to the various derivatives of FOS salts. Pharmacokinetic profiles have been described in humans, chickens, rabbits, cows, dogs, horses and weaning piglets. The low toxicity and potential efficacy of FOS are the main factors that contribute to its use in humans and animals. Thus, it has been used to treat a broad variety of bacterial infections in humans, such as localized peritonitis, brain abscesses, severe soft tissue infections, cystitis and other conditions. In veterinary medicine, FOS is used to treat infectious diseases of broiler chickens and pigs. In broilers, it is administered for the treatment of E. coli and Salmonella spp. infections. In piglets, the drug is prescribed to treat a wide variety of bacterial infections. FOS penetration is demonstrated in phagocytic, respiratory (HEP-2) and intestinal (IPEC-J2) cells. Although not widely used in animals, the drug has shown good results in human medicine. The potentialities of FOS suggest that this drug is a promising candidate for the treatment of infections in veterinary medicine. For these reasons, the aim of this work is to provide animal health practitioners with information on a drug that is not extensively recognized.

Cytocompatibility of a matrix of methylated cassava starch and chitosan

Starches can be used to form edible or biodegradable films, and recently modified starches have been used to form self-supporting films by casting from aqueous solution. In this work, we aimed to propose a novel starch-based composite biomaterial matrix for use in biomedical applications, especially tissue engineering. The goal of the study was to evaluate the cytocompatibility of composite hydrogels of methylated starch and chitosan, using glutaraldehyde as the cross-linker. Commercial cassava starch with high purity (96.69%) was methylated with dimethyl sulfate in order to obtain a rigid material that could possibly render stronger mechanical properties to chitosan hydrogels. Therefore, methylated starch was mixed with a solution of chitosan and the cross-linking was induced by the addition of glutaraldehyde, allowing the formation of hydrogel films which were visualized under scanning electron microscopy. The method of fabrication was optimized based on the capacity of the cells to attach to the material and proliferate. After thorough washes with ethanol and saline solution, human fibroblasts were seeded on top of the gels and allowed to grow for 3 to 5 days. Cell viability was measured using an (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) MMT assay, and cell morphology was visualized by light microscopy. It was found that cells were viable at every time point, with their metabolic activity comparable to the controls (tissue culture plastic and chitosan alone), as well as clear cell–matrix interactions. Moreover, an increase in the metabolic activity over time indicated the capacity of the material to support cell proliferation. The proposed methylated starch–chitosan system is an excellent matrix that allows cell adhesion and could thereby be further assessed as a scaffold for tissue engineering.

RUNX1 is a key target in t(4;11) leukemias that contributes to gene activation through an AF4-MLL complex interaction

The Mixed Lineage Leukemia (MLL) protein is an important epigenetic regulator required for the maintenance of gene activation during development. MLL chromosomal translocations produce novel fusion proteins that cause aggressive leukemias in humans. Individual MLL fusion proteins have distinct leukemic phenotypes even when expressed in the same cell type, but how this distinction is delineated on a molecular level is poorly understood. Here, we highlight a unique molecular mechanism whereby the RUNX1 gene is directly activated by MLL-AF4 and the RUNX1 protein interacts with the product of the reciprocal AF4-MLL translocation. These results support a mechanism of transformation whereby two oncogenic fusion proteins cooperate by activating a target gene and then modulating the function of its downstream product.

Strengthening immunization in a West African country: Mali

OBJECTIVES AND CONTEXT: This paper describes the preliminary outcomes of a collaborative capacity-building initiative performed in Mali to strengthen the immunization program.

METHODS

We conducted baseline assessments, training and post-training assessments in four programmatic areas: vaccine management, immunization safety, surveillance, and vaccine coverage, using adapted World Health Organization (WHO) tools. Impact assessment was done by evaluation of trainee performance, programmatic impact and sustainability.

RESULTS

Qualitative and quantitative improvement of trainee performance was seen after the training interventions: some knowledge improvement, greater compliance with vaccine management practices and improved vaccine coverage. Deficiencies in information transfer to the periphery were identified.

CONCLUSIONS

The program involves shared responsibility for planning, implementation and financing with national stakeholders while emphasizing the training of leaders and managers to ensure sustainability. Although short-term gains were measured, our initial assessments indicate that sustained impact will require improvements in staffing, financing and guidelines to ensure delivery of information and skills to the periphery.

Pharmacological inhibition and silencing of classical IKK-NF-κB pathway by siRNA sensitizes cancer cells to doxorubicin

2059

Background: The IKK/NF-κB pathway (IKK1, IKK2 and NEMO; p65, p50, p52, c-Rel, RelB) is involved in chemoresistance. NF-κB is activable by either a classical or an alternative Ipathway. Here we studied whether NF-κB inhibitors sensitized cells to doxorubicin (dox), and assessed the role of individual IKK or NF-κB subunits by RNA interference [ small interfering RNA (siRNA)] on doxorubicin sensitization. Methods: We used BT474 and MDA-MB453 cells (breast) and HeLa cells (cervix). NF-κB inhibitors were bortezomib (Velcade, a proteasome inhibitor, which inhibits NF-κB by promoting accumulation of the inhibitory Iκ B-α) and a NEMO-Binding-Peptide (NBP, which prevents IKK proteins from complexing). NF-κB DNA binding activity was measured by EMSA. Western blot was used to assess nuclear translocation of individual NF-κB subunits (Iκ B-α, p65, c-Rel, RelB, p50 and p52). BT474 and MDA-MB453 cells were cultured with dox with/without NF-κB inhibitors and viability was assayed by MTT. siRNA was used to transiently down-regulate subunits that act preferentially on the classical NF-κ B (p65, p52, c-Rel, or NEMO) or on the alternative pathway (RelB) in HeLa cells. Chemosensitivity of transfected and control cells to dox was measured by MTT. Results: Dox increased NF-κB activity in BT474 and HeLa cells, as assayed by EMSA and/or by showing Iκ B-α degradation and phosphorylation of p65. Pretreatment of BT474 cells with bortezomib followed by dox resulted in a 30% reduction in cell viability compared to dox alone. Moreover, a 40% higher dox sensitivity was observed when cells were pretreated with a NEMO-Binding-Peptide. Similar data were obtained in MDA-MB453 cells. Transient down-regulation of key members of the classical IKK- NF-κB pathway (p65, p52, c-Rel and NEMO) by siRNA in HeLa cells lead to a 30% increase in dox cytotoxicity. In contrast, silencing of RelB, a key subunit of the alternative pathway, had no effect on dox cytotoxicity under our assay conditions. Conclusions: NF-κB inhibition sensitized cells to dox, implying directly p65, p52, c-Rel and NEMO subunits in chemoresistance, but not RelB. These findings suggest that selective inhibition of the classical IKK-NF-κB pathway is sufficient to improve dox antitumor effects.

[Table: see text]

Indicadores bioquímicos predictivos de fístula faringocutánea postlaringuectomía: un estudio clínico

The aim of this clinical study was to determinate biochemical predictor indicators of postlaryngectomy pharyngocutaneous fistula.

PATIENTS AND METHODS

We have studied 100 patients with T2- 4 a laryngeal and piryform sinus carcinoma who underwent a laryngectomy. All patients were ASA 2-3. We studied serum albumin, protein serum level, cholesterol and lymphocites in each patient. These variables underwent statistical analysis (p < 0.05).

RESULTS

19% of the patients developed a postlaryngectomy pharyngocutaneous fistula, with a long-stay of 25 days vs. 10 days of stay in patients without postlaryngectomy pharyngocutaneous fistula. 7 postlaryngectomy pharyngocutaneous fistula needed surgical repair. Low serum albumin (< 3.5 g/dL) and a low level of serum proteins (< 6.5 g/dL) were predictive indicators of postlaryngectomy pharyngocutaneous fistula (p < 0.05).

CONCLUSIONS

Our results suggest that a low-level of serum proteins and albumin are predictive clinical parameters of postlaryngeal pharyngocutaneous fistula.

Effects of tamoxifen on lipid profile and coagulation parameters in male patients with pubertal gynecomastia

BACKGROUND/AIM

The estrogenic actions of tamoxifen on lipid profiles and hemostasis have been extensively demonstrated in women. Due to limited experience with this drug in males, it is uncertain whether these effects are also present in men. The aim of our study was to assess the response of blood lipids, lipoproteins, and coagulation parameters in a group of men taking tamoxifen.

METHODS

We studied 15 healthy boys with pubertal gynecomastia who were given 10 mg tamoxifen per day. Total testosterone, sex-hormone-binding globulin, estradiol, serum lipids, apolipoprotein B, apolipoprotein A-I, lipoprotein(a), fibrinogen, antithrombin III, von Willebrand factor, and markers of activated coagulation and fibrinolysis were determined at baseline and 1 and 3 months after beginning of the tamoxifen treatment.

RESULTS

Total cholesterol and lipoprotein(a) showed moderate but significant decreases from baseline. Low-density lipoprotein and high-density lipoprotein cholesterol concentrations as well as triglyceride and apolipoprotein B levels became lower, but these changes were not statistically significant. Among clotting parameters, antithrombin III was reduced, and von Willebrand factor increased significantly. Markers of activated coagulation and fibrinolysis remained unchanged throughout the period of therapy.

CONCLUSIONS

The effects of tamoxifen on blood lipids and hemostasis we found in this group of healthy young men were qualitatively similar, but lesser than those previously described in women.

[Human brain activity in response to emotional visual stimuli: open issues and recent data]

INTRODUCTION

The traditional circumplex model on the structure of emotion postulates that this process is organized in two basic dimensions: valence (positive negative) and activation (relaxing activating). This model assumes that the valence activates a single evaluative system. With regard to cerebral activity, two ideas are derived from this assumption: 1) a single set of mechanisms and neural circuits becomes activated in response to both positive and negative events, 2) the faculty of response to adverse and pleasant responses (i.e., latency and intensity with which the neural structures involved can respond) is potentially balanced.

DEVELOPMENT

We describe the debates on these two issues and, subsequently, the current data regarding them are also described. These data indicate that, in response to aversive stimuli (often noxious), neural systems characterized by their ability to produce an immediate response are preferentially activated. On the other hand, pleasant stimuli (which lead to an approaching behavior towards the stimulus) preferentially activate systems associated with more intense and precise information processing. This is a slower but longer lasting type of activity.

CONCLUSION

The data suggest that there are separate mechanisms for the evaluation and preparation of a response according to whether the stimulus is negative or positive.

Emotion, attention, and the 'negativity bias', studied through event-related potentials

Behavioral studies indicate that there exists a 'negativity bias' in the way surrounding events are processed. Particularly, it has been indicated that negative events elicit more rapid and more prominent responses than non-negative events. The objective of the present study was to explore the role of attention in relation to this negativity bias. Three groups of emotional pictures were used as stimuli: positive, negative and neutral. Event-related potentials were recorded from 35 subjects at F5, Fz, F6, C5, Cz, C6, P5, Pz and P6. Valence and arousal content of the stimulation was measured via a questionnaire. The experimental design ensured that subjects whose data were finally analyzed attended to the stimuli. ANOVAs showed that P200, an attention-related component, showed higher amplitudes and shorter latencies in response to negative stimuli than in response to positive stimuli. Additional partial correlation analyses indicated that P200 amplitude, but not latency, significantly associates (at frontal and central sites) with valence content of the stimulation. Therefore, due to the valence-related nature of the bias, it is concluded that intensity aspects (more than timing aspects) of the P200-related attentional processes are particularly involved in the negativity bias.

Recovery of replication-competent virus from CD4 T cell reservoirs and change in coreceptor use in human immunodeficiency virus type 1-infected children responding to highly active antiretroviral therapy

Highly active antiretroviral therapy (HAART) suppresses plasma viremia in most patients with human immunodeficiency virus (HIV) infection. Prospective study of HIV-infected children (n=27) shows that, in 8 of 12 who responded to HAART (>/=0.5 log reduction in plasma HIV RNA), HAART restricted the number of coreceptors used by the predominant HIV isolate (mean number of coreceptors used at baseline was 4, vs. 1 coreceptor used at 6 months after treatment). This decrease was most striking in 6 of 8 children whose HIV coreceptor tropism changed from X4-tropic at baseline to R5-tropic. In 6 of 10 children tested, with plasma HIV RNA levels of <50 copies/mL, R5-tropic virus was isolated from CD4 T cell reservoirs. All the responding children had a significant increase in naive CD4 T cells (P<.05). These results show that persistent HIV T cell reservoirs are present in children and that HAART may influence the number and type of coreceptors used by the predominant virus isolate.

[Partial tricuspid homograft: a new technique for tricuspid valve repair. Report of a case]

The authors report the case of a drug abuser treated successfully for fungal tricuspid endocarditis complicated by massive pulmonary embolism. Partial valvular replacement with a segment of a tricuspid homograft associated with disobliteration of a pulmonary artery was performed. Peroperative transoesophageal echocardiography showed satisfactory tricuspid valve function. The postoperative course was uneventful. After 5 months' follow-up, the patient was asymptomatic and in good general condition. Control echocardiography showed a stable operative result.

New 3-methyoxyflavones, an iridoid lactone and a flavonol from duroia hirsuta

Investigation of the roots of Duroia hirsuta from Ecuador yielded the iridoid lactone duroin (1) together with 3,7,3', 5'-tetramethoxy-4'-hydroxyflavone (2), 3,7,3'-trimethoxy-4', 5'-dihydroxyflavone (3), and 7,3',5'-trimethoxy-3, 4'-dihydroxyflavone (4) as novel constituents.

Exploratory assessment of fish consumption among Asian-origin sportfishers on the St. Lawrence river in the montreal region

An exploratory survey was undertaken in the fall 1995 open-water fishing season with nine Bangladeshi and nine Vietnamese-origin sportfishers. Survey methodology and techniques of dietary and fish intake assessment were adapted to the cultural values and second language of each community. A 70-item instrument assessing sportfishing practices and fish consumption habits was administered by dietitians in participants' homes. Two 24-h diet recalls (aided by photographs taken by the participants) and a fish consumption calendar permitted the assessment of fish intake in the overall dietary context. A fish frequency item addressed consumption of locally available fish species (both sport and market fish) as well as imported frozen or dried species. Annually, Bangladeshi fishers consumed 46.8+/-25.6 sportfish meals, and Vietnamese fishers ate 40. 7+/-35.1 meals. In contrast, Bangladeshis reported greater annual consumption of imported, frozen nonsportfish (76.0+/-40.9 meals), and the Vietnamese ate more ocean than freshwater fish (45.1+/-34.4 ocean fish meals). Fish constituted approximately 19% of all protein foods eaten among the Bangladeshi fishers and 10% in the Vietnamese sample. Plasma and erythrocyte eicosapentanoic acid (EPA):arachidonic acid (AA) ratios supported findings from the fish frequency question showing that the two groups of Asian-origin fishers eat differing quantities of different fish species and that Asian-origin sportfishers-particularly the Bangladeshis-eat fish overall more frequently and in greater variety and quantity than francophone Quebecers; species selection appears to be both culturally motivated and influenced by the availability of St. Lawrence sportfish.

[Carcinoid heart disease]

Carcinoid cardiac disease is a common complication of metastatic carcinoid tumours. It is characterized by tricuspid regurgitation and pulmonary stenosis. A 68 years old woman with a metastatic carcinoid tumour was admitted to hospital for congestive cardiac failure secondary to severe tricuspid regurgitation. Typical carcinoid lesions of the tricuspid and pulmonary valves were observed at echocardiography. A double valve replacement was performed with a favourable outcome. Postoperative echocardiography showed a significant improvement in right ventricular function. Surgical management of carcinoid valvular heart disease of NYHA Stage III patients is associated with an improved 2 years survival (from 8 to 40%) despite a high operative mortality (about 27%). Cardiac surgery remains the only hope of long-term survival with a spectacular improvement in symptoms.