A Phase Ib Study of Durvalumab (MEDI4736) in Combination with Carbon-Ion Radiotherapy and Weekly Cisplatin for Patients with Locally Advanced Cervical Cancer (DECISION Study): The Early Safety and Efficacy Results.

We conducted a phase Ib study to examine the safety of a combination of carbon-ion RT (CIRT) with durvalumab (MEDI4736; AstraZeneca) in patients with locally advanced cervical cancer. This was an open-label, single-arm study with a modified 3 + 3 design. Patients with newly diagnosed histologically proven locally advanced cervical cancer were enrolled. All patients received 74.4 Gy of CIRT in 20 fractions and concurrent weekly cisplatin (chemo-CIRT) at a dose of 40 mg/m2. Durvalumab was administered (1500 mg/body) at weeks two and six. The primary endpoint was the incidence of adverse events (AEs) and serious AEs (SAEs), including dose-limiting toxicity (DLT). All three enrolled patients completed the treatment without interruption. One patient developed hypothyroidism after treatment and was determined to be an SAE. No other SAEs were observed. The patient recovered after levothyroxine sodium hydrate treatment. None of the AEs, including hypothyroidism, were associated with DLT in the present study. All three patients achieved complete responses within the CIRT region concerning treatment efficacy. This phase 1b trial demonstrates the safety of combining chemo-CIRT and durvalumab for locally advanced cervical cancer in the early phase. Further research is required as only three patients were included in this study.

A Multicenter Randomized Controlled Trial To Evaluate the Efficacy and Safety of Nelfinavir in Patients with Mild COVID-19.

Nelfinavir, an orally administered inhibitor of human immunodeficiency virus protease, inhibits the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro. We conducted a randomized controlled trial to evaluate the clinical efficacy and safety of nelfinavir in patients with SARS-CoV-2 infection. We included unvaccinated asymptomatic or mildly symptomatic adult patients who tested positive for SARS-CoV-2 infection within 3 days before enrollment. The patients were randomly assigned (1:1) to receive oral nelfinavir (750 mg; thrice daily for 14 days) combined with standard-of-care or standard-of-care alone. The primary endpoint was the time to viral clearance, confirmed using quantitative reverse-transcription PCR by assessors blinded to the assigned treatment. A total of 123 patients (63 in the nelfinavir group and 60 in the control group) were included. The median time to viral clearance was 8.0 (95% confidence interval [CI], 7.0 to 12.0) days in the nelfinavir group and 8.0 (95% CI, 7.0 to 10.0) days in the control group, with no significant difference between the treatment groups (hazard ratio, 0.815; 95% CI, 0.563 to 1.182; P = 0.1870). Adverse events were reported in 47 (74.6%) and 20 (33.3%) patients in the nelfinavir and control groups, respectively. The most common adverse event in the nelfinavir group was diarrhea (49.2%). Nelfinavir did not reduce the time to viral clearance in this setting. Our findings indicate that nelfinavir should not be recommended in asymptomatic or mildly symptomatic patients infected with SARS-CoV-2. The study is registered with the Japan Registry of Clinical Trials (jRCT2071200023). IMPORTANCE The anti-HIV drug nelfinavir suppresses the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro. However, its efficacy in patients with COVID-19 has not been studied. We conducted a multicenter, randomized controlled trial to evaluate the efficacy and safety of orally administered nelfinavir in patients with asymptomatic or mildly symptomatic COVID-19. Compared to standard-of-care alone, nelfinavir (750 mg, thrice daily) did not reduce the time to viral clearance, viral load, or the time to resolution of symptoms. More patients had adverse events in the nelfinavir group than in the control group (74.6% [47/63 patients] versus 33.3% [20/60 patients]). Our clinical study provides evidence that nelfinavir, despite its antiviral effects on SARS-CoV-2 in vitro, should not be recommended for the treatment of patients with COVID-19 having no or mild symptoms.

LCAT-trial-24 weeks: Protocol for a clinical study to evaluate the safety of regenerative medicine and gene therapy by the autologous transplantation of human lecithin:cholesterol acyltransferase gene-transduced human pre-adipocytes.

Backgrounds: Despite the absolute need for life-long treatment of inherited and genetic diseases, there has been little effort to develop such treatments for most of these conditions due to their rarity. Familial lecithin:cholesterol acyltransferase (LCAT) deficiency is recognized as one such orphan disease. We have been developing an adipocyte-based ex vivo gene therapy/regenerative medicine, a novel methodology that differs from the adeno-associated virus-mediated in vivo gene therapy or ex vivo gene-transduced hematopoietic cell therapy, to treat familial LCAT deficiency. Recently, a first-in-human (FIH) clinical study was conducted under the Act on Securement of Safety of Regenerative Medicine, wherein a patient with familial LCAT deficiency was treated. To obtain approval to put this treatment into practical use, a clinical trial has been designed with reference to the FIH clinical study. Methods: An interventional, open-label, unblinded dose-escalation trial was planned, referring to previous FIH clinical study. The trial aims to evaluate the safety of the investigational product in relation to the characteristics of the investigational product (ex vivo gene/cell therapy product by retroviral vector-mediated LCAT gene transduction) using two doses, and the efficacy of the treatment will be evaluated exploratively. A total of three patients will be enrolled sequentially and followed for 24 weeks after administration. This study is designed as a multicenter trial, with Chiba University Hospital administering and evaluating the safety/efficacy of the investigational products at the prescribed visit. Conclusion: This clinical trial is expected to facilitate the provision of lifelong treatment to many patients with LCAT deficiency. Trial registration number: Japan Registry of Clinical Trials (jRCT2033200096).

Phase Ib study of durvalumab (MEDI4736) in combination with carbon-ion radiotherapy and weekly cisplatin for patients with locally advanced cervical cancer (DECISION study): study protocol for a prospective open-label single-arm study.

INTRODUCTION: Concurrent chemoradiotherapy is considered the standard treatment strategy for locally advanced cervical cancer. Most recent reports indicate that patients with bulky tumours or adenocarcinoma subtypes have poorer local control. Carbon-ion radiotherapy (CIRT) with the concurrent use of chemotherapy has shown promising results in such cases of difficult-to-treat uterine cervical cancer. Programmed death-ligand 1 (PD-L1) upregulation was observed in tumour tissue samples from patients who had undergone CIRT. Thus, a combination of CIRT and anti-PD-L1 antibody may suppress metastasis by activating antitumour immune response, in addition to exhibiting strong local effects. OBJECTIVE: We will assess the safety and tolerability (primary endpoint) of the concomitant use of durvalumab, an anti-PD-L1 antibody, with CIRT and weekly cisplatin for locally advanced cervical cancer. METHODS AND ANALYSIS: This study is a non-randomised, open-label, prospective phase 1b study. Up to 10 patients with histologically proven uterine cervical cancer at stage IIB, IIIA, IIIB, IIIC1 or IVA as per International Federation of Gynecology and Obstetrics (2018) staging will be enrolled. All patients will receive CIRT of 74.4 Gy relative biological effectiveness in 20 fractions over 5 weeks (four fractions per week). Weekly cisplatin at a dose of 40 mg/m2 will be administrated up to five times. Durvalumab at a dose of 1500 mg/body will be administrated at weeks 2 and 6. Safety and tolerability will be evaluated based on the frequency of dose-limiting toxicities until 92 days after CIRT starts. Patients will be followed-up strictly as per the scheduled protocol for 1 year after CIRT initiation. ETHICS AND DISSEMINATION: The Human Research Ethics Committees of QST Hospital (#C21-002) and Chiba University (#2021006) have approved this study protocol. The findings will be published in peer-reviewed journals and presented at scientific conferences. TRIAL REGISTRATION NUMBER: Japan Registry of Clinical Trials (jRCT2031210083), registered on 12 May 2021.

Efficacy and safety of nelfinavir in asymptomatic and mild COVID-19 patients: a structured summary of a study protocol for a multicenter, randomized controlled trial.

OBJECTIVES: The aim of this trial is to evaluate the antiviral efficacy, clinical efficacy, and safety of nelfinavir in patients with asymptomatic and mild COVID-19. TRIAL DESIGN: The study is designed as a multicenter, open-label, blinded outcome assessment, parallel group, investigator-initiated, exploratory, randomized (1:1 ratio) controlled clinical trial. PARTICIPANTS: Asymptomatic and mild COVID-19 patients will be enrolled in 10 university and teaching hospitals in Japan. The inclusion and exclusion criteria are as follows: Inclusion criteria: (1) Japanese male or female patients aged ≥ 20 years (2) SARS-CoV-2 detected from a respiratory tract specimen (e.g., nasopharyngeal swab or saliva) using PCR, LAMP, or an antigen test within 3 days before obtaining the informed consent (3) Provide informed consent Exclusion criteria: (1) Symptoms developed ≥ 8 days prior to enrolment (2) SpO2 < 96 % (room air) (3) Any of the following screening criteria: a) ALT or AST ≥ 5 × upper limit of the reference range b) Child-Pugh class B or C c) Serum creatinine ≥ 2 × upper limit of the reference range and creatinine clearance < 30 mL/min (4) Poorly controlled diabetes (random blood glucose ≥ 200 mg/dL or HbA1c ≥ 7.0%, despite treatment) (5) Unsuitable serious complications based on the assessment of either the principal investigator or the sub-investigator (6) Hemophiliac or patients with a marked hemorrhagic tendency (7) Severe diarrhea (8) Hypersensitivity to the investigational drug (9) Breastfeeding or pregnancy (10) With childbearing potential and rejecting contraceptive methods during the study period from the initial administration of the investigational drug (11) Receiving rifampicin within the previous 2 weeks (12) Participated in other clinical trials and received drugs within the previous 12 weeks (13) Undergoing treatment for HIV infection (14) History of SARS-CoV-2 vaccination or wishes to be vaccinated against SARS-CoV-2 (15) Deemed inappropriate (for miscellaneous reasons) based on the assessment of either the principal investigator or the sub-investigator INTERVENTION AND COMPARATOR: Patients who meet the inclusion criteria and do not meet any of the exclusion criteria will be randomized to either the nelfinavir group or the symptomatic treatment group. The nelfinavir group will be administered 750 mg of nelfinavir orally, three times daily for 14 days (treatment period). However, if a participant tests negative on two consecutive PCR tests of saliva samples, administration of the investigational drug for that participant can be discontinued at the discretion of the investigators. The symptomatic treatment group will not be administered the investigational drug, but all other study procedures and conditions will be the same for both groups for the duration of the treatment period. After the treatment period of 14 days, each group will be followed up for 14 days (observational period). MAIN OUTCOMES: The primary endpoint is the time to negative conversion of SARS-CoV-2. During the study period from Day 1 to Day 28, two consecutive negative PCR results of saliva samples will be considered as the negative conversion of the virus. The secondary efficacy endpoints are as follows: For patients with both asymptomatic and mild disease: area under the curve of viral load, half decay period of viral load, body temperature at each time point, all-cause mortality, incidence rate of pneumonia, percentage of patients with newly developed pneumonia, rate of oxygen administration, and the percentage of patients who require oxygen administration. For asymptomatic patients: incidence of symptomatic COVID-19, incidence of fever (≥ 37.0 °C for two consecutive days), incidence of cough For patients with mild disease: incidence of defervescence (< 37.0 °C), incidence of recovery from clinical symptoms, incidence of improvement of each symptom The secondary safety endpoints are adverse events and clinical examinations. RANDOMIZATION: Patients will be randomized to either the nelfinavir group or the symptomatic treatment group using the electric data capture system (1:1 ratio, dynamic allocation based on severity [asymptomatic], and age [< 60 years]). BLINDING (MASKING): Only the assessors of the primary outcome will be blinded (blinded outcome assessment). NUMBERS TO BE RANDOMIZED (SAMPLE SIZE): The sample size was determined based on our power analysis to reject the null hypothesis, S (t | z =1) = S (t | z = 0) where S is a survival function, t is time to negative conversion, and z denotes randomization group, by the log-rank test with a two-sided p value of 0.05. We estimated viral dynamic parameters by fitting a nonlinear mixed-effects model to reported viral load data, and simulated our primary endpoint from viral-load time-courses that were realized from sets of viral dynamics parameters sampled from the estimated probability distribution of the parameters (sample size: 2000; 1000 each for randomization group). From this estimation of the hazard ratio between the randomization groups for the event of negative conversion using this simulation dataset, the required number of events for rejecting our null hypothesis with a power of 0.80 felled 97.345 by plugging the estimated hazard ratio, 1.79, in Freedman's equation. Therefore, we decided the required number of randomizations to be 120 after consideration of the frequency of censoring and the anticipated rate of withdrawal caused by factors such as withdrawal of consent. TRIAL STATUS: Protocol version 6.0 of February 12, 2021. Recruitment started on July 22, 2020 and is anticipated to be completed by March 31, 2022. TRIAL REGISTRATION: This trial was registered in Japan Registry of Clinical Trials (jRCT) ( jRCT2071200023 ) on 21 July 21, 2020. FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol. The study protocol has been reported in accordance with the Standard Protocol Items: Recommendations for Clinical Interventional Trials (SPIRIT) guidelines (Additional file 2).

Medroxyprogesterone acetate plus metformin for fertility-sparing treatment of atypical endometrial hyperplasia and endometrial carcinoma: trial protocol for a prospective, randomised, open, blinded-endpoint design, dose-response trial (FELICIA trial).

INTRODUCTION: Progestin therapy is the only fertility-sparing treatment option for patients with atypical endometrial hyperplasia (AEH) and endometrial cancer (EC). However, the results of three meta-analyses revealed a high remission rate, as well as an association with a high rate of relapse. We previously conducted a phase II of medroxyprogesterone acetate (MPA) plus metformin as a fertility-sparing treatment for AEH and EC patients, and reported that metformin inhibited disease relapse after remission. METHODS AND ANALYSIS: A randomised, open, blinded-endpoint design phase IIb dose response trial was planned to commence in July 2019. The trial aims to identify the appropriate dose of metformin to be combined with MPA therapy for fertility-sparing treatment of patients with AEH and EC. The primary endpoint of the trial is the 3-year relapse-free survival (RFS) rate. The secondary endpoints are RFS rate, the overall rate of response to MPA therapy, the conception rate after treatment, the outcome of pregnancy, toxicity evaluation and changes in insulin resistance and body mass index. A total of 120 patients will be enrolled from 15 Japanese institutions within a 2.5-year period and followed up for at least 3 years. ETHICS AND DISSEMINATION: The protocol was approved by the institutional review board at Chiba University Hospital and boards at 14 other institutions. The trial will be conducted according to the principles of the World Medical Association's Declaration of Helsinki and in accordance with Good Clinical Practice (GCP) standards. The trial findings will be published in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: Japan Registry of Clinical Trials (jRCT2031190065).

Targeting Excessive EZH1 and EZH2 Activities for Abnormal Histone Methylation and Transcription Network in Malignant Lymphomas.

Although global H3K27me3 reprogramming is a hallmark of cancer, no effective therapeutic strategy for H3K27me3-high malignancies harboring EZH2WT/WT has yet been established. We explore epigenome and transcriptome in EZH2WT/WT and EZH2WT/Mu aggressive lymphomas and show that mutual interference and compensatory function of co-expressed EZH1 and EZH2 rearrange their own genome-wide distribution, thereby establishing restricted chromatin and gene expression signatures. Direct comparison of leading compounds introduces potency and a mechanism of action of the EZH1/2 dual inhibitor (valemetostat). The synthetic lethality is observed in all lymphoma models and primary adult T cell leukemia-lymphoma (ATL) cells. Opposing actions of EZH1/2-polycomb and SWI/SNF complexes are required for facultative heterochromatin formation. Inactivation of chromatin-associated genes (ARID1A, SMARCA4/BRG1, SMARCB1/SNF5, KDM6A/UTX, BAP1, KMT2D/MLL2) and oncovirus infection (HTLV-1, EBV) trigger EZH1/2 perturbation and H3K27me3 deposition. Our study provides the mechanism-based rationale for chemical dual targeting of EZH1/2 in cancer epigenome.

Light quality determines primary production in nutrient-poor small lakes.

The availability of nutrients for primary producers has long been thought to be the main limiting factor for primary productivity in nutrient-poor lake ecosystems. However, recent studies have indicated that the availability of light energy is also important. On the other hand, the amount of phototroph was reported to decrease in summer in Antarctic lakes, furthermore, the light environment underwater was shown containing high amount of ultraviolet energy in small Antarctic lakes. Here, we hypothesized that primary productivity is limited by not only nutrients and simple light quantity but also light quality in nutrient-poor lakes. Then, we investigate factors influencing primary production by benthic phototrophic communities in shallow nutrient-poor lakes. We examine the relationships between primary production in 17 Antarctic freshwater lakes and nutrient concentrations in lake and benthic water, temperature and light energy. Primary production is decreased by ultraviolet energy reaching the lake bed, showing that production is determined by light quality. We also correlate ultraviolet energy in lake water with the catchment area of each lake. Our results show that the underwater light environment has an important influence on primary production as a key limitation factor and is sensitive to materials in runoff from the surrounding environment for pristine lakes.

Polycomb-dependent epigenetic landscape in adult T-cell leukemia.

Adult T-cell leukemia-lymphoma (ATL) shows global gene expression alterations that confer cellular characteristics and unfavorable prognosis. However, molecular mechanisms of the sustained expression changes are largely unknown, because there is no study addressing the relationship between landscapes of the gene expression and epigenetic modifications. Here, we analyzed ATL epigenome and integrated it with transcriptome from primary ATL cells and those from corresponding normal CD4(+)T cells to decipher ATL-specific "epigenetic code" that was critical for cell identity. We found that polycomb-repressive complex 2 (PRC2)-mediated trimethylation at histone H3Lys27 (H3K27me3) was significantly and frequently reprogrammed at half of genes in ATL cells. A large proportion of the abnormal gene downregulation was detected at the early stage of disease progression and was explained by H3K27me3 accumulation. The global H3K27me3 alterations involved ATL-specific gene expression changes that included several tumor suppressors, transcription factors, epigenetic modifiers, miRNAs, and developmental genes, suggesting diverse outcomes by the PRC2-dependent hierarchical regulation. Interestingly, a key enzyme, EZH2, was sensitive to promiscuous signaling network including the NF-κB pathway and was functionally affected by human T-cell leukemia virus type I (HTLV-1) Tax. The Tax-dependent immortalized cells showed H3K27me3 reprogramming that was significantly similar to that of ATL cells. Of note, a majority of the epigenetic silencing has occurred in leukemic cells from indolent ATL and also in HTLV-1-infected T cells from asymptomatic HTLV-1 carriers. Because pharmacologic inhibition of EZH2 reversed epigenetic disruption and selectively eliminated leukemic and HTLV-1-infected cells, targeting the epigenetic elements will hold great promise in treatment and prevention of the onset of ATL and HTLV-1-related diseases.

Establishment of ponasterone A-inducible the wild-type p53 protein-expressing clones from HSC-1 cells, cell growth suppression by p53 expression and the suppression mechanism.

Gene therapy for a variety of human cancers containing the mutant p53 (mt-p53) gene has been performed by direct injection of a retroviral or adenoviral vector containing the wild-type p53 (wt-p53) gene. Because many individuals with skin squamous cell carcinoma (SCC) have been shown to carry the p53 gene mutation, these patients are candidates for p53 gene therapy. For this reason, we established ponasterone A-inducible the wild-type p53 (wt-p53) protein-expressing clones by transfecting a ponasterone-inducible vector containing the wt-p53 gene into HSC-1 cells, which harbor the mutated p53 (m/w) at codon 173 (GTG --> TTG in one allele). Upon the induction of the wt-p53 protein, severe growth suppression was observed. Based on the results of the expression patterns of the p21, p16, RB, BAX and Bcl-2 proteins, as well as on the results of senescence-associated beta-galactosidase staining, the suppression was caused by senescence-like growth arrest of the cells. Although it is generally accepted that the suppression of tumor cell growth is caused by p53-induced apoptosis, permanent G1 arrest induced by p53 is also an important part of the growth-suppression mechanism in p53 gene therapy. The present results should expand the possibilities for p53 gene therapy for human skin SCCs containing the mutant p53 gene.

A case of 'lymphomatosis cerebri' diagnosed in an early phase and treated by whole brain radiation: case report and literature review.

'Lymphomatosis cerebri' (LC) is a term indicating a diffusely infiltrating form of primary central nervous system lymphoma (PCNSL) without evidence of a mass lesion. Not infrequently, diagnostic confusion is caused by its presentation on cranial magnetic resonance images (MRI), which is characterized by diffuse leukoencephalopathy without contrast enhancement. In this report, we describe a 53-year-old, immunocompetent man who had an insidiously progressive dementia and right weakness. On serial MRI in 4 months duration, diffuse white matter lesions without contrast enhancement gradually progressed, which was clinically consistent with his worsening condition. Biopsy specimen demonstrated nondestructive, diffusely infiltrating, large B-cell lymphoma, diagnosing LC. After the biopsy, corticosteroids were initiated, which dramatically alleviated his symptoms. Afterwards, he was treated by whole brain irradiation (total 36Gy) and discharged without noticeable deficits. Diagnosis of LC requires additional examinations generally not performed in the other white matter disorders. In suspected cases, biopsy should be performed to avoid deferring adequate cytostatic treatment.

DNA sequencing and transcriptional analysis of the kasugamycin biosynthetic gene cluster from Streptomyces kasugaensis M338-M1.

Streptomyces kasugaensis M338-M1 produces the aminoglycoside antibiotic kasugamycin (KSM). We previously cloned, sequenced and characterized the KSM acetyltransferase, transporter, and some of the biosynthetic genes from this strain. To identify other potential genes in a chromosome walk experiment, a 6.8-kb EcoRI-PstI region immediately downstream from the KSM transporter genes was sequenced. Five open reading frames (designated as kasN, kasO, kasP, kasQ, kasR) and the 5' region of kasA were found in this region. The genes are apparently co-transcribed as bicistrons, all of which are co-directional except for the kasPQ transcript. Homology analysis of the deduced products of kasN, kasP, kasQ and kasR revealed similarities with known enzymes: KasN, D-amino acid oxidase from Pseudomonas aeruginosa (35% identity); KasP, F420-dependent H4MPT reductase from Streptomyces lavendulae (33% identity); KasQ, UDP-N-acetylglucosamine 2-epimerase from Streptomyces verticillus (45% identity); and KasR, NDP-hexose 3,4-dehydratase from Streptomyces cyanogenus (38% identity); respectively. A gel retardation assay showed that KasT, a putative pathway-specific regulator for this gene cluster, bound to the upstream region of kasN and to the intergenic region of kasQ-kasR, suggesting that the expression of these operons is under the control of the regulator protein.

Aged human skin removes UVB-induced pyrimidine dimers from the epidermis more slowly than younger adult skin in vivo.

Although many studies have been reported on the repair of ultraviolet light (UV)-induced cyclobutane-type pyrimidine dimers (CPDs) in DNA, the effects of aging on the removal of UV-induced CPDs from the human skin epidermis in vivo remains uncertain. Therefore, we employed immunoblotting and immunohistochemical methods using monoclonal antibodies (TDM-2) to CPDs to study age-related differences in the time required for the in vivo removal of UVB-induced CPDs. The flexure surfaces of the upper arms of five young men were exposed to UVB light at a fluence of 35 and 700 mJ/cm2, and four older men were also irradiated with the same doses of UVB mentioned above. Each area of skin was biopsied before and immediately after irradiation, and at 4, 24 h, 2 and 4 days after irradiation in the younger group; and before and immediately after irradiation, and at 24 h, 4, 7, and 14 days after irradiation in the older group. A total of 108 DNA samples were taken from the epidermis of 108 biopsied specimens. These samples were immunoblotted using TDM-2 and the intensities of the immunoprecipitates were measured by photodensitometer. Our results show that the CPDs had been removed from the epidermis at 4 days after irradiation at either dose in the younger group, and between 7-14 days after irradiation in the aged group. The results of our immunohistochemical studies were consistent with those of our immunoblotting studies, and indicated that basal cells repair CPDs more quickly than prickle cells in the epidermis except the amounts at 24 h after UVB irradiation, and that the CPDs were removed by epidermal turnover after the nucleotide excision repair (NER). Our results showed age-associated decline in the NER in vivo, indicating high risk of UV-associated skin cancer.

Destruxin E, a cyclodepsipeptide antibiotic, reduces cyclin D1 levels and inhibits anchorage-independent growth of v-Ki-ras-expressed pMAM-ras-REF cells.

Destruxin E (DE), a cyclodepsipeptide isolated from fermentation broths of Metarhizium sp. MA324, inhibited the growth of v-Ki-ras-expressed pMAM-ras-REF (rasREF) cells in the suspension (anchorage-independent) culture (a) more strongly than that in the substratum-attached (anchorage-dependent) culture (b) or that of v-Ki-ras-unexpressed pMAM-ras-REF (REF) cells in the substratum-attached culture (c); the IC(50) values of DE were 0.07 microM (a), 0.4 microM (b), and 1.2 microM (c). DE arrested G1 phase cell cycle progression of rasREF cells in the substratum-attached culture (b). In rasREF cells treated with DE for 72 h in suspension culture (a), the levels of cyclin D1, cyclin A, p27(Kip1), and hyperphosphorylated Rb were decreased, but the levels of cdk4, cdk6, cdk2, p16(INK4a), and p21(Cip1) were not affected. Among these effects, the decrease in cyclin D1 was prominent. DE decreased the level of cyclin D1 in rasREF cells in the suspension culture (a) at 0.1 microM and in the substratum-attached culture (b) at 1 microM, while the level of cyclin D1 in REF cells in the substratum-attached culture (c) was not decreased at 1 microM. The extent of growth inhibition correlated with the decrease in cyclin D1. The level of cyclin D1 mRNA of rasREF cells in the suspension culture (a) was also decreased by DE. DE decreased cyclin D1 mRNA, resulting in inhibition of anchorage-independent growth of rasREF cells.

Modulation of iron regulatory protein-1 by various metals.

Iron regulatory protein-1 (IRP-1) is known as a cytosolic aconitase and a central regulator of iron (Fe) homeostasis. IRP-1 regulates the expression of Fe metabolism-related proteins by interacting with the Fe-responsive element (IRE) in the untranslated regions of mRNAs of these proteins. However, it is less known whether IRP-1 modulates various non-Fe metals. In the present study, we showed that treatment of homogenously purified IRP-1 with non-Fe metals decreased the affinity to IRE in RNA band shift assays and increased aconitase activity. Non-Fe metals also inhibited (55)Fe incorporation into the fourth labile position of the Fe-S cluster of IRP-1. In PLC hepatoma cells, metal loading inactivated binding activity and activated enzyme activity. It also suppressed transferrin receptor mRNA expression in the cells. These results suggest that various non-Fe metals modulate IRP-1 by conversion of the 3Fe-4S apo-form to a [1 non-Fe metal + 3Fe]-4Fe holo-form.

kasT gene of Streptomyces kasugaensis M338-M1 encodes a DNA-binding protein which binds to intergenic region of kasU-kasJ in the kasugamycin biosynthesis gene cluster.

We previously reported that a 4.2 kb SacI-EcoRI DNA region from Streptomyces kasugaensis M338-M1, a kasugamycin (KSM) producer, included KSM transporter genes (kasKLM). As an extension of that study, a 3.7 kb Psti-SacI DNA region, located at 1.5 approximately 5.2 kb upstream of kasK, was cloned and sequenced, revealing three complete open reading frames, designated kasT, kasU and kasJ. The kasJ gene encodes a protein (KasJ) with a conserved dinucleotide (FAD)-binding motif Homology search for KasJ showed its similarity to NADH: N-amidino-scyllo-inosamine oxidoreductase (StsB) which is involved in biosynthesis of the streptidine moiety of streptomycin (SM) in S. griseus. The kasT gene encodes a DNA-binding protein (KasT), including a helix-turn-helix motif near the center of the sequence. This protein is similar in structure to a pathway-specific activator protein (StrR) that plays a role in regulating the SM biosynthesis gene cluster of S. griseus. A fusion protein (Trx-KasT) clearly showed DNA binding activity with the intergenic region of kasU-kasJ, suggesting that KasT is a pathway-specific regulator of the KSM biosynthesis gene cluster.