Biology and Development of DNA-Targeted Drugs, Focusing on Synthetic Lethality, DNA Repair, and Epigenetic Modifications for Cancer: A Review.

DNA-targeted drugs constitute a specialized category of pharmaceuticals developed for cancer treatment, directly influencing various cellular processes involving DNA. These drugs aim to enhance treatment efficacy and minimize side effects by specifically targeting molecules or pathways crucial to cancer growth. Unlike conventional chemotherapeutic drugs, recent discoveries have yielded DNA-targeted agents with improved effectiveness, and a new generation is anticipated to be even more specific and potent. The sequencing of the human genome in 2001 marked a transformative milestone, contributing significantly to the advancement of targeted therapy and precision medicine. Anticipated progress in precision medicine is closely tied to the continuous development in the exploration of synthetic lethality, DNA repair, and expression regulatory mechanisms, including epigenetic modifications. The integration of technologies like circulating tumor DNA (ctDNA) analysis further enhances our ability to elucidate crucial regulatory factors, promising a more effective era of precision medicine. The combination of genomic knowledge and technological progress has led to a surge in clinical trials focusing on precision medicine. These trials utilize biomarkers for identifying genetic alterations, molecular profiling for potential therapeutic targets, and tailored cancer treatments addressing multiple genetic changes. The evolving landscape of genomics has prompted a paradigm shift from tumor-centric to individualized, genome-directed treatments based on biomarker analysis for each patient. The current treatment strategy involves identifying target genes or pathways, exploring drugs affecting these targets, and predicting adverse events. This review highlights strategies incorporating DNA-targeted drugs, such as PARP inhibitors, SLFN11, methylguanine methyltransferase (MGMT), and ATR kinase.

Clinical utility of Todai OncoPanel in the setting of approved comprehensive cancer genomic profiling tests in Japan.

Comprehensive cancer genome profiling (CGP) has been nationally reimbursed in Japan since June 2019. Less than 10% of the patients have been reported to undergo recommended treatment. Todai OncoPanel (TOP) is a dual DNA-RNA panel as well as a paired tumor-normal matched test. Two hundred patients underwent TOP as part of Advanced Medical Care B with approval from the Ministry of Health, Labour and Welfare between September 2018 and December 2019. Tests were carried out in patients with cancers without standard treatment or when patients had already undergone standard treatment. Data from DNA and RNA panels were analyzed in 198 and 191 patients, respectively. The percentage of patients who were given therapeutic or diagnostic recommendations was 61% (120/198). One hundred and four samples (53%) harbored gene alterations that were detected with the DNA panel and had potential treatment implications, and 14 samples (7%) had a high tumor mutational burden. Twenty-two samples (11.1%) harbored 30 fusion transcripts or MET exon 14 skipping that were detected by the RNA panel. Of those 30 transcripts, 6 had treatment implications and 4 had diagnostic implications. Thirteen patients (7%) were found to have pathogenic or likely pathogenic germline variants and genetic counseling was recommended. Overall, 12 patients (6%) received recommended treatment. In summary, patients benefited from both TOP DNA and RNA panels while following the same indication as the approved CGP tests. (UMIN000033647).

Left Ventricular Mass Influences Relationship Between Filling Pressure and Early-Diastolic Ratio of Inflow Velocity to Mitral Annular Velocity (E/e').

BACKGROUND: Early-diastolic mitral annular velocity (e') and the ratio of early-diastolic left ventricular (LV) inflow velocity (E) to e' (E/e') have been widely used as indexes of LV relaxation and filling pressure, respectively. However, many recent studies have demonstrated that they are not reliable in various clinical settings. We thus investigated the factors influencing these echocardiographic parameters in a multicenter study.Methods and Results:The study group comprised 69 patients, referred for cardiac catheterization, and enrolled in 5 university hospitals. Time constant (τ) and LV mean diastolic pressure (LVMDP) were measured using a micromanometer-tipped catheter. Although e' only weakly correlated with τ (r=-0.35, P<0.01), E/e' modestly correlated with LVMDP (r=0.48, P<0.001). Multivariable analysis revealed that hypertension (ß=-0.33, P<0.01) and LV ejection fraction (LVEF) (ß=0.44, P<0.001) were the independent determinants of e', and LV mass index (LVMI) (ß=0.37, P<0.001) and LVMDP (ß=0.47, P<0.001) were those of E/e'. Additionally, E/e' significantly correlated with LVMDP in patients with normal LVMI (r=0.74, P<0.001) but not in those with increased LVMI. CONCLUSIONS: The coincidence of hypertension and LVEF affected the relationship between LV relaxation and e', whereas LVMI altered the relationship between LV filling pressure and E/e'. Thus, clinical conditions associated with an increase in LVMI, such as LV hypertrophy and LV dilatation, should be considered when estimating the filling pressure from E/e'.

Left Ventricular Global Strain for Estimating Relaxation and Filling Pressure　- A Multicenter Study.

BACKGROUND: Speckle-tracking echocardiography (STE)-derived parameters may have better correlation with left ventricular (LV) relaxation and filling pressure than tissue Doppler-derived parameters. However, it has not been elucidated which parameter - strain or strain rate - and which direction of myocardial deformation - longitudinal or circumferential - is the most useful marker of LV relaxation and filling pressure. METHODS AND RESULTS: We conducted a prospective multicenter study and compared the correlation of tissue Doppler- and STE-derived parameters with the time constant of LV pressure decay (τ) and LV mean diastolic pressure (MDP) in 77 patients. The correlation of early-diastolic mitral annular velocity (e´) with τ was weak (r=-0.32, P<0.01), and that of peak longitudinal strain (LS) was the strongest (r=-0.45, P<0.001) among the STE-derived parameters. There was a modest correlation between LVMDP and the ratio of early-diastolic inflow velocity (E) to e´ (E/e´) (r=0.50, P<0.001). In contrast, the ratio of E to LS (E/LS) correlated strongly with LVMDP (r=0.70, P<0.001). The correlation of E/LS with LVMDP was significantly better than that for E/e´ (P<0.01). Receiver-operating characteristic analysis showed that E/LS had the largest area under the curve for distinguishing elevated LVMDP (E/LS 0.86, E/e´ 0.74, E/A 0.67). CONCLUSIONS: STE-derived longitudinal parameters correlated well with LV relaxation and filling pressure. In particular, E/LS could be more accurate than E/e´ for estimating LV filling pressure. (Circ J 2016; 80: 1163-1170).

Combination of Urinary Sodium/Creatinine Ratio and Plasma Brain Natriuretic Peptide Level Predicts Successful Tolvaptan Therapy in Patients With Heart Failure and Volume Overload.

To evaluate the short-term clinical and hemodynamic effects of tolvaptan therapy and to identify predictors of the therapeutic outcomes, we retrospectively recruited 60 consecutive hospitalized heart failure (HF) patients (70 ± 11 years) with volume overload. The subjects were divided into two groups on the basis of the changes in HF symptom scores and hemodynamic status assessed by right heart catheterization after tolvaptan therapy (median: 7 days). The majority of patients were successfully treated (group 1). However, 22% of patients (group 2) were unsuccessfully treated, in whom 1) the HF symptom score worsened or 2) there was a stationary HF symptom score ≥ 6 points, and mean PCWP > 18 mmHg and mean RAP > 10 mmHg, after tolvaptan therapy. HF symptom scores, hemodynamic parameters, and plasma brain natriuretic peptide (BNP) level improved in group 1, but all of these parameters remained unchanged in group 2. Lower urine sodium/creatinine ratio (UNa/UCr) and higher BNP level at baseline were independently associated with unsuccessful tolvaptan therapy, and UNa/UCr best predicts unsuccessful tolvaptan therapy with a cut-off value of 46.5 mEq/g·Cr (AUC 0.847, 95% CI: 0.718-0.976, sensitivity 77%, specificity 81%, P < 0.01). Double-positive results of UNa/UCr < 46.5 mEq/g·Cr and plasma BNP level > 778 pg/mL predicted unsuccessful tolvaptan therapy with high diagnostic accuracy (sensitivity 54%, specificity 100%, positive predictive value 100%, negative predictive value 89%, and accuracy 90%). In summary, short-term tolvaptan therapy ameliorated HF symptoms and provided hemodynamic improvement in the majority of patients, and UNa/UCr and BNP level strongly predicted the therapeutic outcomes.

Analysis of the binding of bovine and human fibrinogen to ferritin: evidence that fibrinogen is a common ferritin-binding protein in mammals.

Both human and horse fibrinogen are heme-binding proteins, and horse fibrinogen also exhibits heme-mediated ferritin binding. This study found that bovine and human fibrinogen are heme-mediated ferritin-binding proteins and demonstrated direct binding of bovine ferritin to protoporphyrin (PPIX) and its derivatives or to Zn ions. Binding of bovine and human fibrinogen to bovine spleen ferritin coated on microtiter plate wells was detected using an anti-human fibrinogen antibody, and this binding was inhibited in a dose-dependent manner by hemin (iron-PPIX) and also inhibited by Zn-PPIX. PPIX showed less of an inhibitory effect on the binding of bovine and human fibrinogen to bovine ferritin. The inhibitory effect of Sn-PPIX was similar to that of PPIX, but with respect to human fibrinogen, PPIX did not inhibit the binding of human fibrinogen to ferritin. Bovine fibrinogen immobilized on CNBr-activated Sepharose 4B beads showed affinity for hemin, Sn-PPIX, Zn-PPIX, and iron-free PPIX in the order Sn-PPIX < iron-free PPIX < hemin < Zn-PPIX. The fibrinogen beads also directly bound to zinc ions. These results suggest that bovine fibrinogen is a heme- and zinc-binding protein and that binding of circulating mammalian fibrinogen to ferritin is heme mediated.

Reduced canine BRCA2 expression levels in mammary gland tumors.

BACKGROUND: Mammary tumors are the most common tumor type in intact female dogs. Recently, the breast cancer 2 early onset (BRCA2) gene was proposed to be associated with tumorigenesis in dogs. The expression level of BRCA2 is important for its DNA repair function in mammalian cells, and its expression level is linked to tumorigenesis in mammary tissue. However, the expression of canine BRCA2 in mammary tumors is unclear. RESULTS: BRCA2 mRNA levels were compared between seven mammary gland samples and seventeen mammary tumor samples isolated from dogs. The expression level of canine BRCA2 in mammary tumor samples was lower than levels in mammary gland samples. We attempted to identify why the BRCA2 expression level was decreased in mammary tumor samples by promoter sequencing analysis; however, we did not find any mutations in the canine BRCA2 promoter that altered BRCA2 transcription levels. We did detect two types of BRCA2 splice variants in 8 mammary tumor samples. One of the variants induced a frame-shift mutation that could lead to nonsense-mediated mRNA decay, a ubiquitous cellular mechanism that eliminates mRNA containing a premature termination codon. CONCLUSIONS: Reduced expression of canine BRCA2 mRNA in mammary tumor samples is a possible mechanism to explain mammary tumor development in dogs. One possible reason for reduced BRCA2 mRNA levels in these tumor samples was nonsense-mediated mRNA decay, not mutations in the BRCA2 promoter region. While it remains unclear why canine BRCA2 expression levels are reduced in mammary tumor samples, this study found that the expression level of BRCA2 was associated with canine mammary tumorigenesis.

Effectiveness of an Intervention Program to Enhance the Self-Confidence of Kindergarten Teachers Dealing with Radiation-Related Health Concerns from Parents of Young Children: A Quasi-Experimental Study.

OBJECTIVE: This study examined the effectiveness of an intervention program to enhance the self-confidence of kindergarten teachers who address radiation-related health concerns among parents following the Fukushima Daiichi Nuclear Power Plant accident in March 2011, wherein radiation anxiety among mothers with young children was high. Kindergarten teachers are expected to address the concerns of these parents. METHODS: Participants from 2 private kindergartens in Fukushima City were assigned to either the intervention group (n = 10), which received an intervention program comprising lectures, group discussions, and presentations, or the control group (n = 16), which received only written materials used in the intervention program. Changes in the measured scores post-intervention were calculated, and the mean values were compared between both groups using the Student's t-test. RESULTS: The primary outcome was self-confidence, and the difference-in-differences approach was used to assess the effectiveness of the intervention program. The study found a more significant difference between pre- and post-intervention self-confidence in the intervention group compared to the control group (P < 0.01). CONCLUSIONS: The intervention program effectively enhanced the self-confidence of kindergarten teachers in dealing with radiation-related health concerns of parents with young children.

Efficacy and safety of pharmacotherapy for cancer cachexia: A systematic review and network meta-analysis.

BACKGROUND: Cancer cachexia affects more than half of all cancer patients, reducing survival rates. Evidence-based approaches are urgently needed to optimize treatment. METHODS: A systematic review and network meta-analysis were conducted to assess the effectiveness and safety of different pharmacotherapies for cancer cachexia. Three databases (PubMed, Cochrane Library, and Web of Science) were searched for the period from January 1, 2000, to March 20, 2024. The netmeta package in R software was used to calculate the pooled effect, employing a random effects model. RESULTS: Seven placebo-controlled randomized trials involving 1421 patients were analyzed. Pairwise analysis showed that body weight increases were 4.6 kg (95% confidence interval [CI] 0.83-8.37 kg) for olanzapine, 3.82 kg (95% CI 0.73-6.91 kg) for espindolol (20 mg), 2.36 kg (95% CI 1.84-2.89 kg) for anamorelin (100 mg), and 1.31 kg (95% CI 0.42-2.19 kg) for anamorelin (50 mg). In terms of safety profiles, olanzapine demonstrated the lowest odds ratio when compared to placebo, at 0.26 (95% CI 0.07-0.94), followed by anamorelin (50 mg) at 0.86 (95% CI 0.30-2.48), and anamorelin (100 mg) at 0.89 (95% CI 0.42-1.88). However, network meta-analysis could not confirm the superiority of olanzapine over anamorelin in terms of efficacy and safety. CONCLUSION: Both olanzapine and anamorelin are useful in improving body weight in patients with cancer cachexia. Personalization may be helpful for different patients.

Cardiac angiosarcoma with pulmonary and adrenal metastases diagnosed by FDG-PET/CT-guided adrenal biopsy.

Primary cardiac angiosarcoma is a high-grade aggressive tumor with a poor prognosis and low incidence. We describe a case of cardiac angiosarcoma, with pulmonary and adrenal metastases, diagnosed via fluorodeoxyglucose-positron emission tomography/computed tomography-guided adrenal biopsy. Learning objective: Cardiac angiosarcoma should be considered in a patient with a cardiac mass with no tumor cells in the pericardial fluid. Fluorodeoxyglucose-positron emission tomography/computed tomography could be useful in determining the biopsy site.

Quantifying longitudinal right ventricular dysfunction in patients with old myocardial infarction by using speckle-tracking strain echocardiography.

BACKGROUND: We investigated longitudinal right ventricular (RV) function assessed using speckle-tracking strain echocardiography in patient with myocardial infarction (MI), and identified the contributing factors for RV dysfunction. METHODS: We retrospectively studied 71 patients with old MI (the OMI group) and 45 normal subjects (the Control group) who underwent a transthoracic echocardiography. Global and free wall RV peak systolic strains (PSSs) in the longitudinal direction were measured by using speckle-tracking strain echocardiography. Left ventricular (LV) PSSs were measured in the longitudinal, radial and circumferential directions. Cardiac hemodynamics including peak systolic pulmonary artery pressure was also assessed non-invasively. Plasma brain natriuretic peptide (BNP) levels were measured in all patients. RESULTS: In the OMI group, 73% of the patients had a normal estimated peak systolic pulmonary artery pressure of less than 35 mmHg. Global and free wall RV PSS were impaired in the OMI group compared with the Control group, and these RV systolic indices were significantly associated with heart rate, logarithmic transformed plasma BNP, greater than 1 year after onset of MI, Doppler-derived estimated pulmonary vascular resistance, LV systolic indices, LV mass index, infarcted segments within a territory of the left circumflex artery and residual total occlusion in the culprit right coronary artery. Multivariable linear regression analysis indicated that reduced longitudinal LV PSS in the 4-chamber view and BNP levels ≥500 pg/ml were independently associated with reduced global and free wall RV PSS. Moreover, when patients were divided into 3 groups according to plasma BNP levels (BNP <100 pg/ml; n = 31, 100 ≤BNP <500 pg/ml; n = 24, and BNP ≥500 pg/ml; n = 16), only patients with BNP ≥500 pg/ml had a strong correlation between RV PSS and longitudinal LV PSS in the 4-chamber view (r = 0.78 for global RV PSS and r = 0.71 for free wall RV PSS, p <0.05). CONCLUSION: Longitudinal RV systolic strain depends significantly on longitudinal LV systolic strain especially in patients with high plasma BNP levels, but not on estimated peak systolic pulmonary artery pressure. These results indicate that process of RV myocardial dysfunction following MI may be governed by neurohormonal activation which causing ventricular remodeling rather than increased RV afterload.

Predictors of central line-associated bloodstream infections in cancer patients undergoing chemotherapy through implanted venous access ports: a retrospective, observational study.

Background: Central venous catheters (CVCs) are sometimes superior to peripheral vascular access for chemotherapy. Central line-associated bloodstream infections (CLABSIs) are an important complication of CVCs in chemotherapy. Methods: A retrospective, observational study was conducted to investigate patients with implanted venous access ports (PORTs) from July 2010 to June 2021 in a teaching hospital. General conditions of the PORTs, backgrounds, and characteristics of patients were compared between CLABSI cases and uninfected cases to identify predictors of CLABSI. Results: A total of 566 patients with PORTs who underwent chemotherapy were enrolled in this study, with CLABSI identified in 41 patients, for a total of 436,597 catheter-days. The median duration of PORT use was 26 vs. 494 days (P<0.001) in the CLABSI and uninfected groups, respectively. There were no significant differences in tumor classification, staging, white blood cell (WBC) count, neutrophil proportion, lymphocyte proportion, albumin, C-reactive protein (CRP), and performance status between the CLABSI and uninfected groups. Multivariable analysis showed that antibiotic usage within the previous week, total protein (TP), and immediate PORT use were independently associated with CLABSI, and their odds ratios (ORs) were 4.89 [95% confidence interval (CI): 1.67, 14.35], 1.95 (95% CI: 1.14, 3.53), and 3.13 (95% CI: 1.18, 8.30), respectively. The area under the curve (AUC) of the receiver-operating characteristic curve for TP was 0.63, and the cutoff value was 5.9 g/dL. Conclusions: PORT implantation should be avoided in patients who had antibiotic treatment episodes within 1 week, especially for those with low serum TP levels.

Significance of the comprehensive geriatric assessment in the administration of chemotherapy to older adults with cancer: Recommendations by the Japanese Geriatric Oncology Guideline Committee.

INTRODUCTION: The number of older patients with cancer is expected to continue to increase owing to the aging population. Recently, the usefulness of geriatric assessment (GA) conducted by multiple staff members from different medical backgrounds has been reported; however, a consensus on the effectiveness of GA has not yet been achieved. MATERIALS AND METHODS: We, as the Japanese Geriatric Oncology Guideline Committee for elderly patients with cancer, conducted a literature search of randomized controlled trials published before August 2021 that used GA or comprehensive GA (CGA) as an intervention for patients with cancer undergoing chemotherapy. As the key outcomes for answering the clinical question, we focused on survival benefit, adverse events, and quality of life (QOL). After a systematic review of these studies, the expert panel member developed recommendations according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. RESULTS: For older patients with cancer, GA or CGA is suggested during or before chemotherapy (weakly recommended). Chemotherapy-induced adverse events were significantly reduced by GA/CGA interventions without any adverse effects on survival. Health-related QOL tended to improve with the GA/CGA interventions. DISCUSSION: Although, in our opinion, GA/CGA does require time and resources, it poses no harm patients. Therefore, we suggest expanding the human resources and educating skills of medical providers for clinical implementation of GA/CGA.

Iron-dependent binding of bovine milk α-casein with holo-lactoferrin, but not holo-transferrin.

Bovine milk α-casein has been identified as an iron- and heme-binding protein. However, the physiological role of its iron-binding remains to be elucidated in more detail. α-Casein was immobilized on CNBr-activated Sepharose 4B beads, and the α-casein agarose beads efficiently bound hemin as well as ferrous ammonium sulfate (Fe(2+)) as compared with control beads. Additionally, α-casein-beads bound bovine holo-lactoferrin (Lf), but not holo-transferrin. Lf caused the release of Fe(2+) which had bound to the α-casein-agarose beads beforehand. These results suggest that bovine α-casein iron-dependently binds holo-bovine Lf more strongly than Fe(2+), and that strong binding between them may play a physiological role in regulating iron homeostasis in the bovine mammary gland.

Feasibility study of an intervention program to enhance self-confidence of kindergarten teachers who deal with radiation-related health concerns from parents with young children.

BACKGROUND: Following the Fukushima Daiichi Nuclear Power Station accident in March 2011, radiation anxiety was high among residents in affected areas. Enhancing radiation-related health literacy is effective in reducing radiation anxiety. This feasibility study aimed to examine a novel intervention program to enhance the self-confidence of kindergarten teachers who deal with radiation-related health concerns from parents in order to determine the feasibility of conducting a future randomized controlled trial. METHODS: Teachers and administrative staff of two private kindergartens in Fukushima City and members of Media Doctor Japan (a research group for enhancing the quality of health news reporting in Japan) were recruited for study participation. Participants were randomly assigned to intervention and control groups. The intervention group participated in the intervention program, comprised of lectures, group discussions, and presentations. The control group received the same written materials used in the intervention program. The primary outcome of this study was feasibility, assessed via four questions concerning program acceptability and described without quantitative analysis. Secondary outcomes were self-confidence concerning parent consultation (1 question, 4-point Likert scale), radiation-related health knowledge (5 question quiz, 1 point for each correct answer, score: 0-5), and health literacy (assessment developed by Ishilawa, et al., score: 1-5) assessed numerically before and after the intervention. Means and standard deviations of outcomes before and after the intervention and their changes in both groups were reported with groups of participants (kindergartens and the Media Doctor Research Japan) reported separately. No quantitative analyses were performed for secondary outcomes. RESULTS: Five and six kindergarten workers and seven and seven Media Doctor Japan members participated in the intervention and control groups, respectively. Reported acceptability was generally positive, and only one participant gave a negative response regarding program usefulness. Improved self-confidence was found in kindergarten employee participants. Radiation-related health knowledge was higher after the intervention in both kindergarten teachers and Media Doctor Japan members. The amount of change was higher in the intervention group than in the control group. CONCLUSIONS: The intervention program enhanced self-confidence in kindergarten employees. The feasibility of the intervention program for a larger randomized controlled trial was ascertained. Time to conduct lectures and group discussions should be increased to further enhance health literacy. TRIAL REGISTRATIONS: UMIN000042527 [University Hospital Medical Information Network (UMIN) Center] registered on November 25, 2020.

Endovascular therapy for cardiocerebral infarction associated with atrial fibrillation: A case report and literature review.

Background: Cardiocerebral infarction (CCI) is a rare entity that refers to the simultaneous occurrence of acute myocardial infarction and acute ischemic stroke. The management of CCI patients remains unclear. Case Description: An 86-year-old woman with a medical history of paroxysmal atrial fibrillation presented with a sudden onset of consciousness disturbance and right hemiplegia. Computed tomography of the head revealed no intracranial hemorrhage but the left hyperdense middle cerebral artery sign, associated with ST-segment elevation in II, III, and aVF noted on a routine 12-lead electrocardiogram at admission. The patient was immediately brought to the catheterization laboratory and percutaneous coronary intervention (PCI) was performed first, followed by mechanical thrombectomy, resulting in successful revascularization of the both diseases. Conclusion: Although the treatment strategy of CCI may depend on the condition of coronary and cerebral ischemia, it may be appropriate to prioritize coronary angiography and PCI if not acute ischemic stroke is critical.

Effect of diquat-induced oxidative stress on iron metabolism in male Fischer-344 rats.

Diquat toxicity causes iron-mediated oxidative stress; however, it remains unclear how diquat affects iron metabolism. Here, we examined the effect of diquat-induced oxidative stress on iron metabolism in male Fischer-344 rats, with particular focus on gene expression. Hepatic nonheme iron content was unchanged until 20 h after diquat treatment. Hepatic free iron levels increased markedly in the early stages following treatment and remained elevated for at least 6 h, resulting in severe hepatotoxicity, until returning to control levels at 20 h. The level of hepatic ferritin, especially the H-subunit, increased 20 h after diquat treatment due to elevated hepatic ferritin-H mRNA expression. These results indicate that early elevated levels of free iron in the liver of diquat-treated rats cause hepatotoxicity, and that this free iron is subsequently sequestered by ferritin synthesized under conditions of oxidative stress, thus limiting the pro-oxidant challenge of iron. The plasma iron concentration decreased at 6 and 20 h after diquat treatment, whereas the level of plasma interleukin-6 increased markedly at 3 h and remained high until 20 h. In the liver of diquat-treated rats, expression of hepcidin mRNA was markedly upregulated at 3 and 6 h, whereas ferroportin mRNA expression was downregulated slightly at 20 h. Transferrin receptor 1 mRNA expression was significantly upregulated at 3, 6, and 20 h. These results indicate that inhibition of iron release from iron-storage tissues, through stimulation of the interleukin-6-hepcidin-ferroportin axis, and enhanced iron uptake into hepatocytes, mediated by transferrin receptor 1, cause hypoferremia.

Heme-mediated binding of α-casein to ferritin: evidence for preferential α-casein binding to ferrous iron.

Bovine milk α-casein was identified as a ferritin-binding protein, and ferritin is known to be a heme-binding protein. In this study, we found that the binding of α-casein to bovine spleen ferritin in vitro was blocked by hemin, but not by iron-free hemin (protoporphyrin IX) or zinc-protoporphyrin IX, suggesting that the presence of iron in heme play a key role in this interaction. Indeed, the binding of α-casein to ferritin and biotinylated hemin was inhibited by adding excess ferrous ammonium sulfate (FAS). To further elucidate the binding mechanism of α-casein to biotinylated hemin, Ferrozine and nitrilotriacetic acid (NTA) were used as ferrous and ferric iron chelators, respectively. FAS-mediated inhibition of α-casein to biotinylated hemin was neutralized with Ferrozine, but not NTA, while FAS- as well as ferric chloride-mediated inhibition in their interaction was neutralized by NTA. The following ions also inhibited α-casein-biotinylated hemin binding in order of potency of inhibition: FAS (Fe(2+)) << ferric chloride (Fe(3+)) < copper sulfate (Cu(2+)) < zinc sulfate (Zn(2+)) < manganese chloride (Mn(2+)) < calcium chloride (Ca(2+)) < magnesium sulfate (Mg(2+)). These results suggests that the binding of α-casein to ferritin is heme-mediated through direct binding of α-casein to iron in the heme on the surface of ferritin molecule, and that α-casein preferentially binds Fe(2+) compared with any other metal ions, including Fe(3+).

Wheat bran protects Fischer-344 rats from diquat-induced oxidative stress by activating antioxidant system: selenium as an antioxidant.

Wheat bran had a protective effect against diquat toxicity in rats fed a purified diet (PD). We studied the effects of wheat bran on the antioxidant system in the liver of rats treated with saline and diquat. Although feeding wheat bran did not affect the concentration of hepatic non-protein sulfhydryl or the activity of glucose 6-phosphate dehydrogenase in the saline-injected rats, these values were significantly higher in the rats fed PD containing wheat bran (W-PD) than in rats fed only PD after administering diquat. The glutathione peroxidase and reductase activities were significantly elevated by wheat bran in the saline-injected rats. Although the glutathione peroxidase activity was unchanged in both the PD-fed rats and W-PD-fed rats after the diquat treatment, the glutathione reductase activity was significantly decreased in both the PD-fed and W-PD-fed rats. Feeding the rats with PD containing 0.15 ppm selenium as well as with W-PD elevated the activity of hepatic glutathione peroxidase and attenuated the diquat toxicity. These results indicate that wheat bran protected against diquat toxicity by activating the hepatic antioxidant system, and that selenium was the key antioxidant in wheat bran.

Binding of mammalian and avian ferritins with biotinylated hemin: demonstration of preferential binding of the H subunit to heme.

The binding of ferritin to heme has been well studied using commercial horse spleen apoferritin, which is almost entirely composed of the L subunit, suggesting that mammalian ferritins bind heme. The present study revealed that both mammalian holoferritins (commercial horse spleen ferritin and purified horse spleen, bovine spleen and canine liver ferritins with L/H subunit ratios of 4.0, 1.1, and 2.3, respectively) and their apoferritins bound biotinylated hemin; apoferritins had higher binding activity than holoferritins, except for canine holo- and apoferritins, which showed the same binding. Bovine ferritin H subunit homopolymers expressed by a baculovirus expression system showed heme binding and had higher binding activity to biotinylated hemin than the L subunit homopolymer expressed by the same system. These bindings were inhibited by heme but not by iron-free or Zn-protoporphyrin IX (Zn-PPIX). Purified chicken liver holoferritin was found to be composed of only H subunits and showed the highest binding activity with biotinylated hemin compared with mammalian holoferritins. The binding of chicken liver holoferritin to biotinylated hemin was also inhibited by heme but not by PPIX or Zn-PPIX. These results indicate that mammalian and avian ferritins bind heme and that the H subunit preferentially recognizes heme.