Loss of Cavin-2 destabilizes PTEN and enhances Akt signaling pathway in cardiomyocytes.

AIMS: Specific cavins and caveolins, known as caveolae-related proteins, have been implicated in cardiac hypertrophy and myocardial injury. Cavin-2 forms complexes with other caveolae-related proteins, but the role of Cavin-2 in cardiomyocytes (CMs) is poorly understood. Here, we investigated an unknown function of Cavin-2 in CMs. METHODS AND RESULTS: Under cardiac stress-free conditions, systemic Cavin-2 knockout (KO) induced mild and significant CM hypertrophy. Cavin-2 KO suppressed phosphatase and tensin homolog (PTEN) associated with Akt signaling, whereas there was no difference in Akt activity between the hearts of the wild-type and the Cavin-2 KO mice under cardiac stress-free conditions. However, after swim training, CM hypertrophy was more facilitated with enhanced PI3K-Akt activity in the hearts of Cavin-2 KO mice. Cavin-2 knockdown neonatal rat CMs (NRCMs) using adenovirus expressing Cavin-2 shRNA were hypertrophied and resistant to hypoxia and H2O2-induced apoptosis. Cavin-2 knockdown increased Akt phosphorylation in NRCMs, and an Akt inhibitor inhibited Cavin-2 knockdown-induced anti-apoptotic responses in a dose-dependent manner. Cavin-2 knockdown increased PIP3 production and attenuated PTEN at the membrane fraction of NRCMs. Immunostaining and immunoprecipitation showed that Cavin-2 was associated with PTEN at the plasma membrane of NRCMs. A protein stability assay showed that Cavin-2 knockdown promoted PTEN destabilization in NRCMs. In an Angiotensin II (2-week continuous infusion)-induced pathological cardiac hypertrophy model, CM hypertrophy and CM apoptosis were suppressed in cardiomyocyte-specific Cavin-2 conditional KO (Cavin-2 cKO) mice. Because Cavin-2 cKO mouse hearts showed increased Akt activity but not decreased extracellular signal-regulated kinase activity, suppression of pathological hypertrophy by Cavin-2 loss may be due to increased survival of healthy CMs. CONCLUSIONS: Cavin-2 plays a negative regulator in the PI3K-Akt signaling in CMs through interaction with PTEN. Loss of Cavin-2 enhances Akt activity by promoting PTEN destabilization, which promotes physiological CM hypertrophy and may enhance Akt-mediated cardioprotective effects against pathological CM hypertrophy.

Extranodal NK/T-cell lymphoma with localized relapse in bone marrow of lower leg detected using PET-CT.

Extranodal natural killer (NK)/T-cell lymphoma (ENKTL) is a rare subtype of non-Hodgkin lymphoma (NHL) with poor prognosis, particularly in relapsed or refractory patients. Thus, timely detection of relapse and appropriate disease management are crucial. We present two patients with ENKTL, wherein positron emission tomography-computed tomography (PET-CT) with total-body coverage after induction therapy, detected newly relapsed regions in the bone marrow of the lower leg prior to progression. Case 1: A 47-year-old woman with nasal obstruction, showing 18F-fluoro-deoxyglucose (FDG) uptake in the nasal cavity (Lugano stage IE). After induction therapy (RT-2/3 DeVIC), PET-CT revealed abnormal uptake only in the right fibula. Case 2: A 68-year-old man with a skin nodule/ulcer and an enlarged right inguinal lymph node was diagnosed with advanced ENKTL. A PET-CT scan revealed abnormal uptake in the subcutaneous mass of the right medial thigh, lymph nodes, and descending colon (Lugano stage IV). After induction therapy, PET-CT revealed new abnormal uptake only in the left tibia. In both patients, CT-guided biopsy confirmed ENKTL recurrence. Moreover, PET-CT with whole-body coverage was useful for the timely assessment of relapse and detection of asymptomatic bone involvement. This approach allowed for modifications to treatment strategies in certain patients.

Dose Individualization of Cefepime for Febrile Neutropenia in Patients With Lymphoma or Multiple Myeloma: Implications for Therapeutic Drug Monitoring.

BACKGROUND: Optimal cefepime dosing is a challenge because of its dose-dependent neurotoxicity. This study aimed to determine individualized cefepime dosing for febrile neutropenia in patients with lymphoma or multiple myeloma. METHODS: This prospective study enrolled 16 patients receiving cefepime at a dose of 2 g every 12 hours. Unbound concentrations were determined at 0.5 hours, 7.2 hours [at the 60% time point of the 12 hours administration interval (C7.2h)], and 11 hours (trough concentration) after the first infusion (rate: 2 g/h). The primary and secondary end points were the predictive performance of the area under the unbound concentration-time curve (AUC unbound ) and the effect of unbound cefepime pharmacokinetic parameters on clinical response, respectively. RESULTS: The mean (SD) AUC unbound was 689.7 (226.6) mcg h/mL, which correlated with C7.2h (R 2 = 0.90), and the Bayesian posterior AUC unbound using only the trough concentration (R 2 = 0.66). Although higher exposure was more likely to show a better clinical response, each parameter did not indicate a statistical significance between positive and negative clinical responses ( P = 0.0907 for creatinine clearance (Ccr), 0.2523 for C7.2h, 0.4079 for trough concentration, and 0.1142 for AUC unbound ). Cutoff values were calculated as 80.2 mL/min for Ccr (sensitivity: 0.889, specificity: 0.714), 18.6 mcg/mL for C7.2h (sensitivity: 0.571, specificity: 1.000), and 9.2 mcg/mL for trough concentration (sensitivity: 0.571, specificity: 1.000). When aiming for a time above 100% the minimum inhibitory concentration, both continuous infusion of 4 g/d and intermittent infusion of 2 g every 8 hours achieved a probability of approximately 100% at a minimum inhibitory concentration of 8 mcg/mL. CONCLUSIONS: Therapeutic drug monitoring by sampling at C7.2h or trough can facilitate rapid dose optimization. Continuous infusion of 4 g/d was recommended. Intermittent dosing of 2 g every 8 hours was alternatively suggested for patients with a Ccr of 60-90 mL/min.

Emphysematous changes as red flag signs preceding rapidly progressive infectious aortic disease: two case reports.

BACKGROUND: Infectious aortic disease is a rare and fatal disease, that requires the appropriate intervention. An accurate diagnosis should be promptly established. However, this is difficult because the clinical manifestations of this disease vary and are non-specific. CASE PRESENTATION: (CASE 1) An 87-year-old male, presenting with generalized malaise and weight loss, was admitted for further examination. A chest computed tomography (CT) showed mediastinal emphysema. Empirical intravenous antibiotics were administered to address the non-specific infectious findings in the laboratory data. The treatment was effective, and the patient fully recovered. However, he was in shock due to aortic rupture and marked pseudo aneurysmal formation around the aortic arch day 25 of hospitalization. An emergency total aortic arch replacement was performed, and the patient was discharged. (CASE 2) An 82-year-old male who had undergone Y-graft replacement in the abdominal aorta 15 years previously was admitted due to general malaise and anorexia. Abdominal CT revealed emphysematous changes adjacent to the abdominal aorta. The patient responded favorably to empirical treatment with intravenous antibiotics and was discharged 19 days after admission. Four days after discharge, the patient went into cardiac arrest after an episode of hematemesis. Abdominal CT revealed an enlarged stomach and duodenum, filled with massive high-density contents proximal to the abdominal aorta. He died of hemorrhagic shock despite cardiopulmonary resuscitation. CONCLUSIONS: Although emphysematous changes are rare, they are red flag signs during the early stage of infectious aortic disease. Thus, physicians should remain vigilant for this kind of critical sign.

Waldenstrom's macroglobulinemia-like B cell lymphoma with MYD88 L265P mutation and t(14;18)(q32;q21) involving IGH-MALT1.

A 65-year-old woman was referred to the hospital for further investigation of weight loss, hyperproteinemia, and anemia. Serum immunofixation electrophoresis revealed IgM-κ M protein. Bone marrow examination revealed an increase in the number of B -cells with immunoglobulin kappa light-chain restriction. Although the MYD88 L265P mutation was identified in bone marrow mononuclear cells, which suggested the diagnosis of Waldenstrom's macroglobulinemia (WM), a fusion signal of IgH-MALT1, which is commonly observed in extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) lymphoma, was also identified. Here, we describe a rare case of low-grade B-cell lymphoma with MYD88 L265P mutations accompanying IgH-MALT1.

IFNα primes cancer cells for Fusicoccin-induced cell death via 14-3-3 PPI stabilization.

The natural product family of the fusicoccanes (FCs) has been shown to display anti-cancer activity, especially when combined with established therapeutic agents. FCs stabilize 14-3-3 protein-protein interactions (PPIs). Here, we tested combinations of a small library of FCs with interferon α (IFNα) on different cancer cell lines and report a proteomics approach to identify the specific 14-3-3 PPIs that are induced by IFNα and stabilized by FCs in OVCAR-3 cells. Among the identified 14-3-3 target proteins are THEMIS2, receptor interacting protein kinase 2 (RIPK2), EIF2AK2, and several members of the LDB1 complex. Biophysical and structural biology studies confirm these 14-3-3 PPIs as physical targets of FC stabilization, and transcriptome as well as pathway analyses suggest possible explanations for the observed synergistic effect of IFNα/FC treatment on cancer cells. This study elucidates the polypharmacological effects of FCs in cancer cells and identifies potential targets from the vast interactome of 14-3-3s for therapeutic intervention in oncology.

[Follicular T-cell lymphoma successfully treated with long-term corticosteroid].

Follicular T-cell lymphoma (FTCL) is a rare disease, recently defined in the revised WHO classification Tumours of Haematopoietic and lymphoid tissues (4th edition). Although angioimmunoblastic T-cell lymphoma (AITL) and FTCL share similar T follicular helper (TFH) cell immunophenotypes and gene mutations, the clinical course of FTCL is not well characterized. Herein, we report the case of a 91-year-old woman with FTCL, who was successfully treated with corticosteroid. The patient, who had systemic lymphadenopathy and splenomegaly, was first diagnosed with necrotizing lymphadenitis. Re-biopsy was performed because of her persistent lymphadenopathy, which revealed FTCL. She was treated with corticosteroid because of her advanced age, poor performance, edema, and pleural effusion. After administering 100 mg prednisone, her condition improved and was discharged with prednisone tapering. Six-month positron emission tomography-computed tomography (PET-CT) scan showed complete metabolic remission. With a low dose of prednisone (6-10 mg), she remained disease-free for >3 years. Thus, these findings suggest that corticosteroid treatment is effective in some patients with peripheral T-cell lymphoma of TFH origin, including FTCL.

Predictive impact of soluble interleukin-2 receptor and number of extranodal sites for identification of patients at very high risk of CNS relapse in diffuse large B-cell lymphoma.

There remains an unmet clinical need to identify which patients with diffuse large B-cell lymphoma (DLBCL) would benefit from central nervous system (CNS) prophylaxis, due to the low positive predictive value (PPV; 10%-15%) of the currently available predictive models. To stratify patients at high risk of developing CNS relapse, we retrospectively analyzed 182 patients with DLBCL initially treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), or a R-CHOP-like regimen. Among them, 17 patients relapsed with CNS involvement, and the 2-year rate of CNS relapse was 7.9%. Upon carrying out multivariate analysis, ≥3 extranodal sites and elevated soluble interleukin-2 receptor (sIL-2R) levels at diagnosis were identified as independent risk factors for CNS relapse. The 2-year and 3.5-year rates of CNS relapse were 57.1% and 78.6%, respectively, in patients with both elevated sIL-2R and ≥3 extranodal sites. Furthermore, combined use of these risk factors of both elevated sIL-2R and ≥3 extranodal sites resulted in a high PPV (71.4%), negative predictive value (93.1%), and overall accuracy (92.3%) for undergoing CNS relapse. In conclusion, we propose a simple and valuable tool to predict patients with DLBCL at very high risk of CNS relapse.

Beneficial impact of first-line mogamulizumab-containing chemotherapy in adult T-cell leukaemia-lymphoma.

Chemotherapy in combination with mogamulizumab (Mog) was approved in Japan in 2014 for untreated aggressive adult T-cell leukaemia-lymphoma (ATL), but the survival benefit remains unclear. Therefore, we retrospectively analysed clinical outcomes in 39 transplant-ineligible patients with untreated aggressive ATL at Kumamoto University Hospital between 2010 and 2021. The probability of four-year overall survival was 46.3% in the first-line Mog-containing treatment group compared to 20.6% in the chemotherapy-alone group (p = 0.033). Furthermore, this survival benefit was observed even in the elderly. In conclusion, first-line Mog-containing treatment can be a promising strategy for transplant-ineligible patients with ATL, especially in the elderly.

[Adult T-cell leukemia/lymphoma diagnosed by RNA in situ hybridization for HTLV-1 bZIP factor].

A 62-year-old man visited the Department of Otorhinolaryngology at our hospital with a chief complaint of a pharyngeal mass. He was admitted to our department with a diagnosis of T-cell lymphoma based on a biopsy of a mesopharyngeal tumor. Although clonality analysis was not performed due to the lack of an appropriate sample, we considered the possibility of lymphoma-type (Lugano classification stage II) adult T-cell leukemia-lymphoma (ATL), as the anti-HTLV-1 antibody was positive. During the course of the disease, the peripheral blood smear revealed atypical lymphocytes with cleaved nuclei, and inverse PCR was performed with DNA extracted from those cells; however, the result showed that the pattern of HTLV-1 proviral DNA integration sites was polyclonal. Further, we performed RNA in situ hybridization targeting HTLV-1 bZIP factor (HBZ-ISH) using the formalin-fixed paraffin-embedded (FFPE) tissue samples of the mesopharyngeal tumor, and a high expression of HBZ was found in the tumor cells, leading to the diagnosis of ATL. These findings suggest the effectiveness of the novel diagnostic method using FFPE tissue samples for ATL.

Requirement of Cavin-2 for the expression and stability of IRß in adequate adipocyte differentiation.

OBJECTIVE: Adipogenesis plays an essential role in maintaining energy and hormonal balance. Cavin-2, one of the caveolae-related proteins, is abundant in adipocytes, the leading site of adipogenesis. However, the details of the roles of Cavin-2 in adipogenesis remain unknown. Here, we demonstrate the requirement of Cavin-2 for the expression and stability of IRß in adequate adipocyte differentiation. METHODS: Cavin-2 knockout (Cavin-2 KO) and wild-type (WT) mice were fed with a high-fat diet (HFD) for 8 weeks. We evaluated body weight, food intake, and several tissues. Glucose homeostasis was assessed by glucose and insulin tolerance tests. Insulin signaling in epididymal white adipose tissue (eWAT) was determined by Akt phosphorylation. In vitro study, we evaluated adipocyte differentiation, adipogenesis-related genes, and insulin signaling to clarify the relationship between Cavin-2 and adipogenesis under the manipulation of Cavin-2 expression. RESULTS: Caveolae structure decreased in eWAT of Cavin-2 KO mice and Cavin-2 knockdown 3T3-L1 cells. Cavin-2 enhanced the stability of insulin receptor (IR) through direct association at the plasma membrane in adipocytes, resulting in accelerated insulin/IR/Akt signaling-induced adipogenic gene expression in insulin-containing solution-stimulated 3T3-L1 adipocytes. IR-mediated Akt activation also enhanced Cavin-2 and IR expression. Cavin-2 knockout mice showed insulin resistance with dyslipidemia and pathological hypertrophic adipocytes after a HFD. CONCLUSIONS: Cavin-2 enhances IR stability through binding IR and regulates insulin signaling, promoting adequate adipocyte differentiation. Our findings highlight the pivotal role of Cavin-2 in adipogenesis and lipid metabolism, which may help to develop novel therapies for pathological obesity and adipogenic disorders.

Differential Kat3 Usage Orchestrates the Integration of Cellular Metabolism with Differentiation.

The integration of cellular status with metabolism is critically important and the coupling of energy production and cellular function is highly evolutionarily conserved. This has been demonstrated in stem cell biology, organismal, cellular and tissue differentiation and in immune cell biology. However, a molecular mechanism delineating how cells coordinate and couple metabolism with transcription as they navigate quiescence, growth, proliferation, differentiation and migration remains in its infancy. The extreme N-termini of the Kat3 coactivator family members, CBP and p300, by far the least homologous regions with only 66% identity, interact with members of the nuclear receptor family, interferon activated Stat1 and transcriptionally competent ß-catenin, a critical component of the Wnt signaling pathway. We now wish to report based on multiomic and functional investigations, utilizing p300 knockdown, N-terminal p300 edited and p300 S89A edited cell lines and p300 S89A knockin mice, that the N-termini of the Kat3 coactivators provide a highly evolutionarily conserved hub to integrate multiple signaling cascades to coordinate cellular metabolism with the regulation of cellular status and function.

Discovering protein-protein interaction stabilisers by native mass spectrometry.

Protein-protein interactions (PPIs) are key therapeutic targets. Most PPI-targeting drugs in the clinic inhibit these important interactions; however, stabilising PPIs is an attractive alternative in cases where a PPI is disrupted in a disease state. The discovery of novel PPI stabilisers has been hindered due to the lack of tools available to monitor PPI stabilisation. Moreover, for PPI stabilisation to be detected, both the stoichiometry of binding and the shift this has on the binding equilibria need to be monitored simultaneously. Here, we show the power of native mass spectrometry (MS) in the rapid search for PPI stabilisers. To demonstrate its capability, we focussed on three PPIs between the eukaryotic regulatory protein 14-3-3σ and its binding partners estrogen receptor ERα, the tumour suppressor p53, and the kinase LRRK2, whose interactions upon the addition of a small molecule, fusicoccin A, are differentially stabilised. Within a single measurement the stoichiometry and binding equilibria between 14-3-3 and each of its binding partners was evident. Upon addition of the fusicoccin A stabiliser, a dramatic shift in binding equilibria was observed with the 14-3-3:ERα complex compared with the 14-3-3:p53 and 14-3-3:LRRK2 complexes. Our results highlight how native MS can not only distinguish the ability of stabilisers to modulate PPIs, but also give important insights into the dynamics of ternary complex formation. Finally, we show how native MS can be used as a screening tool to search for PPI stabilisers, highlighting its potential role as a primary screening technology in the hunt for novel therapeutic PPI stabilisers.

p300 Serine 89: A Critical Signaling Integrator and Its Effects on Intestinal Homeostasis and Repair.

Differential usage of Kat3 coactivators, CBP and p300, by ß-catenin is a fundamental regulatory mechanism in stem cell maintenance and initiation of differentiation and repair. Based upon our earlier pharmacologic studies, p300 serine 89 (S89) is critical for controlling differential coactivator usage by ß-catenin via post-translational phosphorylation in stem/progenitor populations, and appears to be a target for a number of kinase cascades. To further investigate mechanisms of signal integration effected by this domain, we generated p300 S89A knock-in mice. We show that S89A mice are extremely sensitive to intestinal insult resulting in colitis, which is known to significantly increase the risk of developing colorectal cancer. We demonstrate cell intrinsic differences, and microbiome compositional differences and differential immune responses, in intestine of S89A versus wild type mice. Genomic and proteomic analyses reveal pathway differences, including lipid metabolism, oxidative stress response, mitochondrial function and oxidative phosphorylation. The diverse effects on fundamental processes including epithelial differentiation, metabolism, immune response and microbiome colonization, all brought about by a single amino acid modification S89A, highlights the critical role of this region in p300 as a signaling nexus and the rationale for conservation of this residue and surrounding region for hundreds of million years of vertebrate evolution.

Safety and pharmacokinetics of polatuzumab vedotin in Japanese patients with relapsed/refractory B-cell non-Hodgkin lymphoma: a phase 1 dose-escalation study.

OBJECTIVE: A phase 1 dose-escalation study of polatuzumab vedotin (pola) was conducted to assess safety, pharmacokinetics and preliminary antitumor activity of pola in Japanese patients with relapsed/refractory B-cell non-Hodgkin lymphoma. METHODS: Patients received pola (1.0 or 1.8 mg/kg) intravenously every 21 days until disease progression or intolerance. Intra-patient dose escalation was prohibited. Tolerability was determined by the standard 3 + 3 rule. Blood sampling was performed to characterize pharmacokinetics. Antitumor activity was evaluated through computed tomography and bone marrow sampling. RESULTS: Four patients received pola 1.0 mg/kg; three received 1.8 mg/kg. Patients had follicular lymphoma (n = 4) or diffuse large B-cell lymphoma (n = 3), median age of 62 years, received a median of 3 prior therapies; six were female. Pola was well tolerated in both cohorts, with no dose-limiting toxicities observed. The most common adverse event was peripheral sensory neuropathy (n = 4). Grade 3 adverse events were cholecystitis and neutrophil count decreased (one each; both 1.0 mg/kg), and syncope and cataract (one each; both 1.8 mg/kg). The plasma half-life of antibody-conjugate monomethyl auristatin E was 4.43-7.98 days, and systemic exposure of unconjugated monomethyl auristatin E was limited in both cohorts. Four patients achieved objective responses (three complete, one partial) without disease progression during the study. CONCLUSIONS: This phase 1 dose-escalation study demonstrated that pola has an acceptable safety profile and offers encouraging antitumor activity to Japanese patients with relapsed/refractory B-cell non-Hodgkin lymphoma. Pola 1.8 mg/kg, the recommended phase 2 dose, was tolerable in Japanese patients.

HTLV-1 induces T cell malignancy and inflammation by viral antisense factor-mediated modulation of the cytokine signaling.

Human T cell leukemia virus type 1 (HTLV-1) is the etiologic agent of a T cell neoplasm and several inflammatory diseases. A viral gene, HTLV-1 bZIP factor (HBZ), induces pathogenic Foxp3-expressing T cells and triggers systemic inflammation and T cell lymphoma in transgenic mice, indicating its significance in HTLV-1-associated diseases. Here we show that, unexpectedly, a proinflammatory cytokine, IL-6, counteracts HBZ-mediated pathogenesis. Loss of IL-6 accelerates inflammation and lymphomagenesis in HBZ transgenic mice. IL-6 innately inhibits regulatory T cell differentiation, suggesting that IL-6 functions as a suppressor against HBZ-associated complications. HBZ up-regulates expression of the immunosuppressive cytokine IL-10. IL-10 promotes T cell proliferation only in the presence of HBZ. As a mechanism of growth promotion by IL-10, HBZ interacts with STAT1 and STAT3 and modulates the IL-10/JAK/STAT signaling pathway. These findings suggest that HTLV-1 promotes the proliferation of infected T cells by hijacking the machinery of regulatory T cell differentiation. IL-10 induced by HBZ likely suppresses the host immune response and concurrently promotes the proliferation of HTLV-1 infected T cells.

Polypharmacological Perturbation of the 14-3-3 Adaptor Protein Interactome Stimulates Neurite Outgrowth.

Targeting protein-protein interactions (PPIs) is a promising approach in the development of drugs for many indications. 14-3-3 proteins are a family of phosphoprotein-binding molecules with critical functions in dozens of cell signaling networks. 14-3-3s are abundant in the central nervous system, and the small molecule fusicoccin-A (FC-A), a tool compound that can be used to manipulate 14-3-3 PPIs, enhances neurite outgrowth in cultured neurons. New semisynthetic FC-A derivatives with improved binding affinity for 14-3-3 complexes have recently been developed. Here, we use a series of screens that identify these compounds as potent inducers of neurite outgrowth through a polypharmacological mechanism. Using proteomics and X-ray crystallography, we discover that these compounds extensively regulate the 14-3-3 interactome by stabilizing specific PPIs, while disrupting others. These results provide new insights into the development of drugs to target 14-3-3 PPIs, a potential therapeutic strategy for CNS diseases.