Vascular Endothelial Growth Factor Receptor Inhibitors Impair Left Ventricular Diastolic Functions.

Vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR-TKIs) frequently induce cardiovascular adverse events, though VEGFR-TKIs contribute to the improvement of the prognosis of patients with malignancies. It is widely accepted that VEGFR-TKIs impair left ventricular systolic functions; however, their effects on diastolic functions remain to be fully elucidated. The purpose of this study was to analyze the impact of VEGFR-TKIs on left ventricular diastolic functions. This study was designed as a retrospective single-center cohort study in Japan. We assessed 24 cases who received VEGFR-TKI monotherapy (sunitinib, sorafenib, pazopanib, axitinib) with left ventricular ejection fraction (LVEF) above 50% during the therapy at the Osaka University Hospital from January 2008 to June 2019. Left ventricular diastolic functions were evaluated by the change in echocardiographic parameters before and after the VEGFR-TKI treatment. Both septal e' and lateral e's decreased after treatment (septal e': before, 6.1 ± 1.8; after, 5.0 ± 1.9; n = 21, P < 0.01; lateral e': before, 8.7 ± 2.8; after, 6.9 ± 2.3; n = 21, P < 0.01). E/A declined after VEGFR-TKIs administration, though not statistically significantly. In 20 cases with at least one risk factor for heart failure with preserved ejection fraction (HFpEF), E/A significantly decreased (0.87 ± 0.34 versus 0.68 ± 0.14; P < 0.05) as well as the septal and lateral e's. These results suggest that treatment with VEGFR-TKIs impairs left ventricular diastolic functions in patients with preserved LVEF, especially in those with risk factors for HFpEF.

Progesterone receptor membrane component 1 leads to erlotinib resistance, initiating crosstalk of Wnt/ß-catenin and NF-κB pathways, in lung adenocarcinoma cells.

In non-small-cell lung cancer, mutation of epidermal growth factor receptor (EGFR) stimulates cell proliferation and survival. EGFR tyrosine kinase inhibitors (EGFR-TKIs) such as erlotinib are used as first-line therapy with drastic and immediate effectiveness. However, the disease eventually progresses in most cases within a few years due to the development of drug resistance. Here, we explored the role of progesterone membrane component 1 (PGRMC1) in acquired resistance to erlotinib and addressed the molecular mechanism of EGFR-TKI resistance induced by PGRMC1. The erlotinib-sensitive cell line PC9 (derived from non-small-cell lung cancer) and the erlotinib-resistant cell line PC9/ER were used. In proteomic and immunoblotting analyses, the PGRMC1 level was higher in PC9/ER cells than in PC9 cells. WST-8 assay revealed that inhibition of PGRMC1 by siRNA or AG-205, which alters the spectroscopic properties of the PGRMC1-heme complex, in PC9/ER cells increased the sensitivity to erlotinib, and overexpression of PGRMC1 in PC9 cells reduced their susceptibility to erlotinib. In the presence of erlotinib, immunoprecipitation assay showed that AG-205 suppressed the interaction between EGFR and PGRMC1 in PC9/ER cells. AG-205 decreased the expression of ß-catenin, accompanied by up-regulation of IκBα (also known as NFKBIA). Furthermore, AG-205 reduced the expression of ß-TrCP (also known as BTRC), suggesting that PGRMC1 enhanced the crosstalk between NF-κB (also known as NFKB) signaling and Wnt/ß-catenin signaling in an erlotinib-dependent manner. Finally, treatment with the Wnt/ß-catenin inhibitor XAV939 enhanced the sensitivity of PC9/ER cells to erlotinib. These results suggest that PGRMC1 conferred resistance to erlotinib through binding with EGFR in PC9/ER cells, initiating crosstalk between the Wnt/ß-catenin and NF-κB pathways.

Eukaryotic translation initiation factor 3 subunit C is associated with acquired resistance to erlotinib in non-small cell lung cancer.

The acquisition of resistance to EGFR tyrosine kinase inhibitors (EGFR-TKIs) is one of the major problems in the pharmacotherapy against non-small cell lung cancers; however, molecular mechanisms remain to be fully elucidated. Here, using a newly-established erlotinib-resistant cell line, PC9/ER, from PC9 lung cancer cells, we demonstrated that the expression of translation-related molecules, including eukaryotic translation initiation factor 3 subunit C (eIF3c), was upregulated in PC9/ER cells by proteome analyses. Immunoblot analyses confirmed that eIF3c protein increased in PC9/ER cells, compared with PC9 cells. Importantly, the knockdown of eIF3c with its siRNAs enhanced the drug sensitivity in PC9/ER cells. Mechanistically, we found that LC3B-II was upregulated in PC9/ER cells, while downregulated by the knockdown of eIF3c. Consistently, the overexpression of eIF3c increased the number of autophagosomes, proposing the causality between eIF3c expression and autophagy. Moreover, chloroquine, an autophagy inhibitor, restored the sensitivity to erlotinib. Finally, immunohistochemical analyses of biopsy samples showed that the frequency of eIF3c-positive cases was higher in the patients with EGFR-TKI resistance than those prior to EGFR-TKI treatment. Moreover, the eIF3c-positive cases exhibited poor prognosis in EGFR-TKI treatment. Collectively, the upregulation of eIF3c could impair the sensitivity to EGFR-TKI as a novel mechanism of the drug resistance.

The Metabolism of Methazolamide in Immortalized Human Keratinocytes, HaCaT Cells.

OBJECTIVE: Drug therapy is occasionally accompanied by an idiosyncratic severe toxicity, which occurs very rarely, but can lead to patient mortality. Methazolamide, an anti-glaucomatous agent, could cause severe skin eruptions called Stevens-Johnson syndrome/toxic epidermal necrolyis (SJS/TEN). Its precise etiology is still uncertain. In this study, the metabolism of methazolamide was investigated in immortalized human keratinocytes to reveal the possible mechanism which causes SJS/TEN. METHODS: The metabolism of methazolamide was studied using immortalized human keratinocytes, HaCaT cells. HPLC was used to isolate a metabolite from the culture medium. Mass spectrometry (LCMS/ MS) was employed for its characterization. Three typical chemical inducers were assessed for the inducibility of cytochrome P450, and methimazole was used as the inhibitor of flavin-containing monooxygenase (FMO). RESULTS: A sulfonic acid, N-[3-methyl-5-sulfo-1,3,4-thiadiazol-2(3H)-ylidene]acetamide (MSO) was identified as the final metabolite. Dexamethasone and ß-naphthoflavone behaved as an inducer of cytochrome P450 in the metabolism, but isoniazid did not. The effect of methimazole was not consistent. We did not detect any glucuronide nor any mercapturic acid (N-acetylcysteine conjugate). CONCLUSION: N-[3-methyl-5-sulfo-1,3,4-thiadiazol-2(3H)-ylidene]acetamide (MSO) is not considered to be a direct product of an enzymatic reaction, but rather an auto-oxidation product of N-[3-methyl-5- sulfe-1,3,4-thiadiazol-2(3H)-ylidene]acetamide, a chemically unstable sulfenic acid, which is produced by cytochrome P450 from the ß-lyase product of cysteine conjugate of methazolamide. MSO is considered to be susceptible to glutathione and to return to glutathione conjugate of methazolamide, forming a futile cycle. A hypothetical scenario is presented as to the onset of the disease.

Gab1 adaptor protein acts as a gatekeeper to balance hepatocyte death and proliferation during acetaminophen-induced liver injury in mice.

UNLABELLED: Acetaminophen (APAP) overdose is the leading cause of drug-induced acute liver failure. In APAP-induced acute liver failure, hepatocyte death and subsequent liver regeneration determines the prognosis of patients, making it necessary to identify suitable therapeutic targets based on detailed molecular mechanisms. Grb2-associated binder 1 (Gab1) adaptor protein plays a crucial role in transmitting signals from growth factor and cytokine receptors to downstream effectors. In this study, we hypothesized that Gab1 is involved in APAP-induced acute liver failure. Hepatocyte-specific Gab1 conditional knockout (Gab1CKO) and control mice were treated with 250 mg/kg of APAP. After APAP treatment, Gab1CKO mice had significantly higher mortality and elevated serum alanine aminotransferase levels compared to control mice. Gab1CKO mice had increased hepatocyte death and increased serum levels of high mobility group box 1, a marker of hepatocyte necrosis. In addition, Gab1CKO mice had reduced hepatocyte proliferation. The enhanced hepatotoxicity in Gab1CKO mice was associated with increased activation of stress-related c-Jun N-terminal kinase (JNK) and reduced activation of extracellular signal-regulated kinase and AKT. Furthermore, Gab1CKO mice showed enhanced mitochondrial translocation of JNK accompanied by an increase in the release of mitochondrial enzymes into the cytosol, which is indicative of increased mitochondrial dysfunction and subsequent nuclear DNA fragmentation. Finally, in vitro experiments showed that Gab1-deficient hepatocytes were more susceptible to APAP-induced mitochondrial dysfunction and cell death, suggesting that hepatocyte Gab1 is a direct target of APAP-induced hepatotoxicity. CONCLUSION: Our current data demonstrate that hepatocyte Gab1 plays a critical role in controlling the balance between hepatocyte death and compensatory hepatocyte proliferation during APAP-induced liver injury.

Multicomponent high-performance liquid chromatography/tandem mass spectrometry analysis of ten chemotherapeutic drugs in wipe samples.

Progress in chemotherapy leads to increased numbers and variety of chemotherapeutic drugs, and multicomponent analysis of these drugs is a necessary step. We used liquid chromatography-tandem mass spectrometry and developed a multicomponent analysis of ten drugs used in chemotherapy: vindesine, vincristine, vinblastine, doxorubicin, epirubicin, ifosfamide, cyclophosphamide, irinotecan, docetaxel, and paclitaxel. We selected five internal standards for each category of drug, because the ionization efficiencies of product ions varied widely. The total run time was 22min, applying a gradient elution of water and acetonitrile in the presence of 0.1% formic acid. The lower limit of quantification was 50ng/wipe samples for vindesine, vincristine, and vinblastine, and 5ng/wipe samples for the remaining seven drugs. Accuracy (88.6-112.9%, 85.2-111.7%) and precision (1.0-11.5%CV, 3.6-14.4%CV) in within-run and between-run assays of QC solutions were acceptable. Without outliers, in within-run and between-run assays of QC samples, accuracy was 90.6-113.9% and 91.1-130.4%, respectively, and precision was 2.2-19.0%CV and 4.8-14.9%CV, respectively. Accuracy and precision of High QC samples of irinotecan were deviated. Our analysis procedure has sufficient sensitivity and is convenient enough for regular monitoring.

Evaluation of environmental contaminations and occupational exposures involved in preparation of chemotherapeutic drugs.

Many healthcare workers are concerned about the risk of occupational exposures to hazardous drugs. The Japanese Society of Hospital Pharmacists (JSHP) revised the "Guidelines for the Handling of Antineoplastic Drugs in Hospitals", however, the precautions and awareness of handling drugs varied in institutions. We assessed the levels of environmental contaminations in our hospital and urinary excretion of cyclophosphamide (CP) and ifosfamide (IF) in pharmacists and nurses. In environmental studies, we obtained samples by wiping the surfaces around two biological safety cabinets (BSCs) on eight days for four months. One BSC was equipped in hospital pharmacy and the other was equipped in an oncology ward, and used for preparing chemotherapeutic drugs for outpatients and for inpatients, respectively. We obtained the urine samples from 6 pharmacists and 2 nurses. We used solid phase extraction (SPE) as a convenient extraction procedure and liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) for the analysis of the samples. CP was detected on the working surfaces inside both BSCs, and detected at low levels on the back surfaces of the BSCs and at the working tables around the BSCs. IF over the LLOQ was not detected in both BSCs. CP and IF were not detected in all urine samples of pharmacists and nurses. Detection frequencies and amounts of these drugs were low levels, compared with previous reports in Japan, and our results showed that improving awareness about handling hazardous drugs could reduce the risk of the occupational exposures.