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The inhibition of GHR enhanced cytotoxic effects of etoposide on neuroblastoma. Cell Signal 2021; 86:110081. [PMID: 34252534 DOI: 10.1016/j.cellsig.2021.110081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 07/02/2021] [Accepted: 07/06/2021] [Indexed: 11/22/2022]
Abstract
Etoposide, a DNA damage-inducing agent, is widely used to treat neuroblastoma. Etoposide binds to and inhibits topoisomerase II, thereby inducing the DNA damage response. However, the underlying mechanism of etoposide resistance in neuroblastoma remains unclear. The results of the present study revealed that etoposide upregulated growth hormone receptor (GHR) expression levels in etoposide-resistant neuroblastoma cells, suggesting that GHR upregulation may be involved in the underlying mechanism of etoposide resistance. Thus, the combined effect of GHR knockdown and etoposide treatment on cell viability, apoptosis and migration in vitro, as well as tumor growth in mouse xenograft models in vivo, was subsequently analyzed. The results of cell viability and colony formation assays demonstrated that GHR knockdown enhanced the inhibitory effects of etoposide on cell viability and sensitized cells to etoposide. The enhanced cell viability was discovered to be, at least in part, due to the increase in etoposide-induced apoptosis following GHR knockdown. Moreover, the knockdown of GHR enhanced the inhibitory effect of etoposide on cell migration. Mouse xenograft studies confirmed the effects of GHR silencing in etoposide-resistant neuroblastoma progression in vivo. Furthermore, the effects of GHR knockdown in etoposide resistance were hypothesized to occur via the inactivation of the MEK/ERK signaling pathway. In conclusion, the results of the present study provided novel insight into the underlying mechanism of etoposide resistance and a potential target for the treatment of etoposide-resistant neuroblastoma.
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Multifocal Pyoderma Gangrenosum with an Underlying Hemophagocytic Lymphohistiocytosis: Case Report and the Review of the Literature. Dermatol Ther (Heidelb) 2021; 11:1217-1237. [PMID: 34176093 PMCID: PMC8322207 DOI: 10.1007/s13555-021-00571-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Indexed: 11/11/2022] Open
Abstract
Pyoderma gangrenosum (PG) is an uncommon, serious, ulcerating skin disease of uncertain etiology. It manifests as a noninfectious, progressive necrosis of the skin characterized by sterile neutrophilic infiltrates. It seems to be a disorder of the immune system. PG is associated with certain underlying conditions in at least 50% of cases. Therefore, it is important to look carefully for comorbidities in every patient with PG and treat them adequately to improve the prognosis. Here, we demonstrate a 35-year-old man diagnosed with multifocal PG and hemophagocytic lymphohistiocytosis (HLH) with fatal outcome, despite combined, long-term, intensive dermatological and hematological treatment with high doses of steroids, cyclosporin, intravenous immunoglobulins (IVIG), HLH-2004 protocol with intravenously administered etoposide, and anakinra. This case is presented owing to the extremely rare coexistence of PG and HLH and the related diagnostic and therapeutic difficulties. It is also worth underlying that the diagnosis of HLH should perhaps be considered in the presence of a high percentage of double-negative T lymphocytes (DNTs) in flow cytometry, after excluding the diagnosis of lymphoma and leukemia. In this article we have also performed and present the critical literature review of local and systemic options in the management of PG lesions based on a detailed search of the PubMed database.
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Ma J, Liang Y, Wu M, Xie M, Hua J, Hu Y, Yang R, Zou Z, Wang X, Xu Y, Wang X, Ye X, Xie Y. Survival Benefit and Efficiency of Low Dose Decitabine With CEG Regimen Compared to Decitabine Alone in the Elderly MDS - A Multicenter, Retrospective Study. CLINICAL LYMPHOMA MYELOMA & LEUKEMIA 2021; 21:e792-e800. [PMID: 34226168 DOI: 10.1016/j.clml.2021.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/22/2021] [Accepted: 06/03/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Decitabine are used in the treatment of myelodysplastic syndrome (MDS), but none trials reported overall survival improvement. METHODS High-risk MDS and MDS transformed AML (sAML) patients (IPSS-R > 4.5, age above 60 years) in 6 medical centers of China were treated and compared a new regimen (decitabine with CEG) consisted of low dose decitabine (15 mg/m2, days 1-3), low dose etoposide (30 mg/m2, days 4,6,8,10,12), cytarabine (10 mg/m2 per day, days 4-12) and granulocyte colony-stimulating factor (G-CSF, 5ug/kg, adjusted by patients' WBC level, 12 hours prior to decitabine administration) with decitabine alone. The endpoints were death and disease progression. RESULTS The baseline characteristics of these 2 groups were equivalent and none patients received prior chemotherapy. The treatment response rate (P= .048) and progression free survival (PFS, P = .030) all demonstrated significant improvement compared with decitabine alone. Decitabine with CEG regimen had attained a CR rate of 45.7%, a median OS of 36 (19-53) months and a median PFS of 34 (16.7-51.3) months in high-risk MDS patients, a CR rate of 40% in sAML. While decitabine alone only attained a median OS of 26 (24.5-27.5) months and a CR rate of 18.2% as well as a median progression free survival of 20 (17.6-22.4) months in MDS patients. Treatment response to CR or PR and TP53 mutation were 2 prognostic factor for OS and PFS in decitabine with CEG regimen. CONCLUSION Decitabine with CEG regimen showed some promising advantage in elderly, high-risk MDS.
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Maleki H, Hosseini Najafabadi MR, Webster TJ, Hadjighassem MR, Sadroddiny E, Ghanbari H, Khosravani M, Adabi M. Effect of Paclitaxel/ etoposide co-loaded polymeric nanoparticles on tumor size and survival rate in a rat model of glioblastoma. Int J Pharm 2021; 604:120722. [PMID: 34022255 DOI: 10.1016/j.ijpharm.2021.120722] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/11/2021] [Accepted: 05/17/2021] [Indexed: 12/18/2022]
Abstract
The aim of this work is to co-load paclitaxel (PTX) and etoposide (ETP) in methoxy poly(ethylene glycol)-poly(lactic-co-glycolic acid) nanoparticles (mPEG-PLGA NPs) to overcome pharmacokinetics and physiological limitations and enhance therapeutic efficacy for treating intracranial glioblastoma. Both drugs were loaded into mPEG-PLGA NPs by a nano-precipitation method. The resultant NPs demonstrated an enhanced cytotoxic effect indicated by lower IC50 values and augmented cell apoptosis to U87 and C6 glioma cell lines compared to both free drugs. Additionally, blood compatibility assays showed that the PTX/ETP co-loaded mPEG-PLGA NPs did not induce blood hemolysis, blood clotting, or platelet aggregation. In vivo anti-glioma efficacy evaluation in rats bearingintracranialC6glioma revealed a superior anti-glioma activity for the treatment with PTX/ETP co-loaded mPEG-PLGA NPs compared to other formulations, particularly a significantly longer median survival, 76 days compared to 36 days for free PTX and 37 days for free ETP treatment, respectively, and higher tumor regression, proved by magnetic resonance imaging (MRI).
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Zhao W, Dovas A, Spinazzi EF, Levitin HM, Banu MA, Upadhyayula P, Sudhakar T, Marie T, Otten ML, Sisti MB, Bruce JN, Canoll P, Sims PA. Deconvolution of cell type-specific drug responses in human tumor tissue with single-cell RNA-seq. Genome Med 2021; 13:82. [PMID: 33975634 PMCID: PMC8114529 DOI: 10.1186/s13073-021-00894-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 04/23/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Preclinical studies require models that recapitulate the cellular diversity of human tumors and provide insight into the drug sensitivities of specific cellular populations. The ideal platform would enable rapid screening of cell type-specific drug sensitivities directly in patient tumor tissue and reveal strategies to overcome intratumoral heterogeneity. METHODS We combine multiplexed drug perturbation in acute slice culture from freshly resected tumors with single-cell RNA sequencing (scRNA-seq) to profile transcriptome-wide drug responses in individual patients. We applied this approach to drug perturbations on slices derived from six glioblastoma (GBM) resections to identify conserved drug responses and to one additional GBM resection to identify patient-specific responses. RESULTS We used scRNA-seq to demonstrate that acute slice cultures recapitulate the cellular and molecular features of the originating tumor tissue and the feasibility of drug screening from an individual tumor. Detailed investigation of etoposide, a topoisomerase poison, and the histone deacetylase (HDAC) inhibitor panobinostat in acute slice cultures revealed cell type-specific responses across multiple patients. Etoposide has a conserved impact on proliferating tumor cells, while panobinostat treatment affects both tumor and non-tumor populations, including unexpected effects on the immune microenvironment. CONCLUSIONS Acute slice cultures recapitulate the major cellular and molecular features of GBM at the single-cell level. In combination with scRNA-seq, this approach enables cell type-specific analysis of sensitivity to multiple drugs in individual tumors. We anticipate that this approach will facilitate pre-clinical studies that identify effective therapies for solid tumors.
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Sardou-Cezar I, Lopes BA, Andrade FG, Fonseca TCC, Fernandez TDS, Larghero P, de Souza RQ, Loth G, Ribeiro LL, Bonfim C, Morgado ES, Marschalek R, Meyer C, Pombo-de-Oliveira MS. Therapy-related acute myeloid leukemia with KMT2A-SNX9 gene fusion associated with a hyperdiploid karyotype after hemophagocytic lymphohistiocytosis. Cancer Genet 2021; 256-257:86-90. [PMID: 34034210 DOI: 10.1016/j.cancergen.2021.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 04/23/2021] [Accepted: 05/02/2021] [Indexed: 12/14/2022]
Abstract
Therapy-related acute myeloid leukemia (t-AML) following treatment with topoisomerase-II inhibitors has been increasingly reported. These compounds (e.g. etoposide) promote DNA damage and are associated with KMT2A rearrangements. They are widely used as first-line treatment in hemophagocytic lymphohistiocytosis (HLH). Here we describe a newborn who developed t-AML after HLH treatment. We provide detailed clinical, cytogenetic, and molecular characteristics of this patient, including the identification of a novel gene fusion - KMT2A-SNX9 - in t-AML. Considering the dismal outcome of this case, we discuss the side-effects of etoposide administration during HLH treatment in infants.
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Naymagon L, Tremblay D, Mascarenhas J. The Efficacy of Etoposide-Based Therapy in Adult Secondary Hemophagocytic Lymphohistiocytosis. Acta Haematol 2021; 144:560-568. [PMID: 33827086 DOI: 10.1159/000514920] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 02/02/2021] [Indexed: 12/18/2022]
Abstract
Data supporting the use of etoposide-based therapy in hemophagocytic lymphohistiocytosis (HLH) arise largely from pediatric studies. There is a lack of comparable data among adult patients with secondary HLH. We conducted a retrospective study to assess the impact of etoposide-based therapy on outcomes in adult secondary HLH. The primary outcome was overall survival. The log-rank test was used to compare Kaplan-Meier distributions of time-to-event outcomes. Multivariable Cox proportional hazards modeling was used to estimate adjusted hazard ratios (HRs) with 95% confidence intervals (CIs). Ninety adults with secondary HLH seen between January 1, 2009, and January 6, 2020, were included. Forty-two patients (47%) received etoposide-based therapy, while 48 (53%) received treatment only for their inciting proinflammatory condition. Thirty-three patients in the etoposide group (72%) and 32 in the no-etoposide group (67%) died during follow-up. Median survival in the etoposide and no-etoposide groups was 1.04 and 1.39 months, respectively. There was no significant difference in survival between the etoposide and no-etoposide groups (log-rank p = 0.4146). On multivariable analysis, there was no association between treatment with etoposide and survival (HR for death with etoposide = 1.067, 95% CI: 0.633-1.799, p = 0.8084). Use of etoposide-based therapy was not associated with improvement in outcomes in this large cohort of adult secondary HLH patients.
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Wu C, Yi X, Xu R, Zhang M, Xu Y, Ma Y, Gao L, Zha Z. Biodistribution of etoposide via intratumoral chemotherapy with etoposide-loaded implants. Drug Deliv 2021; 27:974-982. [PMID: 32611260 PMCID: PMC8216434 DOI: 10.1080/10717544.2020.1787558] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Etoposide (VP16) is the traditional antitumor agent which has been widely used in a variety of cancers. However, intravenous administration of VP16 was limited in clinical application because of its low aqueous solubility, poor bioavailability and dose-limiting adverse effects. Local chemotherapy with VP16-loaded drug delivery systems could provide a continuous release of drug at the target site, while minimizing the systemic toxicity. In this study, we prepared the poly-l-lactic acid (PLLA) based VP16-loaded implants (VP16 implants) by the direct compression method. The VP16 implants were characterized with regards to drug content, micromorphology, drug release profiles, differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) analyses. Furthermore, the biodistribution of VP16 via intratumoral chemotherapy with VP16 implants was investigated using the murine Lewis lung carcinoma model. Our results showed that VP16 dispersed homogenously in the polymeric matrix. Both in vitro and in vivo drug release profiles of the implants were characterized by high initial burst release followed by sustained release of VP16. The VP16 implants showed good compatibility between VP16 and the excipients. Intratumoral chemotherapy with VP16 implants resulted in significantly higher concentration and longer duration of VP16 in tumor tissues compared with single intraperitoneal injection of VP16 solution. Moreover, we found the low level of VP16 in plasma and normal organ tissues. These results suggested that intratumoral chemotherapy with VP16 implants enabled high drug concentration at the target site and has the potential to be used as a novel method to treat cancer.
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Restoration of ligatable "clean" double-strand break ends is the rate-limiting step in the rejoining of ionizing-radiation-induced DNA breakage. DNA Repair (Amst) 2021; 93:102913. [PMID: 33087279 DOI: 10.1016/j.dnarep.2020.102913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Radiotherapy kills malignant cells by generating double-strand breaks (DSBs). Ionizing- radiation (IR) generates "dirty" DSBs, which associates with blocking chemical adducts at DSB ends. Homologous-directed repair (HDR) efficiently removes IR-induced blocking adducts from both 3' and 5' ends of DSBs. Nonhomologous end-joining (NHEJ) rejoins virtually all DSBs in G1 phase and ∼80 % of DSBs in G2 phase. However, DNA Ligase IV, an essential NHEJ factor, rejoins only "clean" ligatable DSBs carrying 3'-OH and 5'-phosphate DSB ends but not dirty DSBs. Recent studies have identified a number of nucleases, especially the MRE11 nuclease, as key factors performing the removal of blocking chemical adducts to restore clean ligatable DSBs for subsequent NHEJ. This restoration, but not subsequent NHEJ, is the rate-limiting step in the rejoining of IR- induced DSBs. This review describes repair factors that contribute to the restoration of clean DSBs before NHEJ.
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Funt SA, McHugh DJ, Tsai S, Knezevic A, O'Donnell D, Patil S, Silber D, Bromberg M, Carousso M, Reuter VE, Carver BS, Sheinfeld J, Motzer RJ, Bajorin DF, Bosl GJ, Feldman DR. Four Cycles of Etoposide plus Cisplatin for Patients with Good-Risk Advanced Germ Cell Tumors. Oncologist 2021; 26:483-491. [PMID: 33586274 PMCID: PMC8176973 DOI: 10.1002/onco.13719] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 02/05/2021] [Indexed: 01/08/2023] Open
Abstract
Background The National Comprehensive Cancer Network recommends either three cycles of bleomycin, etoposide, and cisplatin or four cycles of etoposide and cisplatin (EPx4) as initial chemotherapy for the treatment of good‐risk germ cell tumors (GCTs). To assess the response, toxicity, and survival outcomes of EPx4, we analyzed our experience. Material and Methods Response and survival outcomes, selected toxicities, and adherence to chemotherapy dose and schedule were assessed in patients with good‐risk GCT who received EPx4 at Memorial Sloan Kettering Cancer Center between 1982 and 2016. The results were compared with our past results and published data. Results Between 1982 and 2016, 944 patients with GCT were treated with EPx4, 289 who were previously reported plus 655 treated between January 2000 and August 2016. A favorable response was achieved in 928 of 944 patients (98.3%). Five‐year progression‐free, disease‐specific, and overall survival rates were 93.9%, 98.6%, and 97.9%, respectively. Median follow‐up was 7.3 years (range, 2.8 months to 35.5 years). Viable, nonteratomatous malignant GCT was present in 3.5% of 432 postchemotherapy retroperitoneal lymph node dissection specimens from patients with nonseminomatous GCT. Febrile neutropenia and thromboembolic events occurred in 16.0% and 8.9%, respectively, with one treatment‐related death. In the more recent 655‐patient cohort, full‐dose EPx4 was administered to 631 (96.3%), with deviations from planned treatment driven mainly by vascular (n = 13), hematologic (n = 11), renal (n = 7), or infectious (n = 5) events. Conclusion EPx4 is highly effective and well tolerated in patients with good‐risk GCTs and remains a standard of care. Implications for Practice Four cycles of etoposide and cisplatin (EPx4) is a standard‐of‐care regimen for all patients with good‐risk germ cell tumors with a favorable response rate and disease‐specific survival of 98%. Full‐dose administration of etoposide and cisplatin and complete resection of residual disease lead to optimal outcomes. EPx4 should be the recommended regimen in active smokers, patients with reduced or borderline kidney function, and patients aged 50 years or older, which are patient groups at increased risk for bleomycin pulmonary toxicity. Because of a risk of acquired severe pulmonary illness, EPx4 may also be favored for patients who vape or use e‐cigarettes and during ongoing transmission of severe acute respiratory syndrome coronavirus 2. The NCCN recommends either three cycles of bleomycin, etoposide, and cisplatin (BEPx3) or four cycles of etoposide and cisplatin (EPx4) as initial chemotherapy for the treatment of good‐risk germ cell tumors. This article assesses outcomes specific to EPx4 treatment.
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Ohmoto A, Fuji S. Clinical feasibility of oral low-dose etoposide and sobuzoxane for conventional chemotherapy-intolerant lymphoma patients. Expert Rev Anticancer Ther 2021; 21:715-722. [PMID: 33656972 DOI: 10.1080/14737140.2021.1898376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Introduction: In Japan, etoposide or sobuzoxane, a type of topoisomerase II inhibitor, is orally administered in patients with lymphoma who cannot tolerate conventional combination chemotherapy. However, the related clinical data remain to be fully summarized.Areas covered: We evaluate the efficacy and toxicity of etoposide and sobuzoxane.Expert opinion: Previous studies on etoposide or sobuzoxane monotherapy, including those among patients who could not tolerate conventional chemotherapy, suggested a favorable overall response rate (ORR) with moderate gastrointestinal or liver/renal toxicity. As for adult T-cell leukemia/lymphoma, a clinical trial with a limited sample size exhibited an ORR of >70%. Remarkably, the percentage of patients with a poor performance status was high among those receiving etoposide/sobuzoxane. Given a lack of randomized studies, etoposide/sobuzoxane might be a therapeutic option for lymphoma in a palliative setting. In the future, prospective trials with a homologous treatment schedule are warranted, in which the association between clinical efficacy and characteristics of lymphomas, such as specific gene alterations, should be elucidated.
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Tyriakidis K, Stadlmann S, Pederiva S. Long-Lasting Complete Remission of Small-Cell Carcinoma of the Pancreas with Carboplatin and Etoposide Complicated by Gallbladder Adenocarcinoma Diagnosed during Follow-Up. Case Rep Oncol 2021; 14:365-370. [PMID: 33776730 PMCID: PMC7983696 DOI: 10.1159/000514048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 12/20/2020] [Indexed: 11/19/2022] Open
Abstract
Small-cell carcinoma of the pancreas (PSCC) is a highly aggressive neoplasia with a dismal prognosis. It is extremely rare, with only a few cases reported in the literature. There is a paucity of clinical data to guide management and since the disease is mainly diagnosed at an advanced stage standard treatment consists of chemotherapy based upon treatment protocols used for small-cell lung cancer. We report the case of a female diagnosed with PSCC who achieved complete clinical remission after treatment with carboplatin and etoposide. During a 3-year follow-up the patient developed a gallbladder adenocarcinoma that was treated by surgical resection but relapsed within 20 months with widespread hematogenous metastasis.
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Fernández-Ferreira R, De la Peña-López IR, Zamudio-Coronado KW, Delgado-Soler LA, Torres-Pérez ME, Bourlón-de Los Ríos C, Cortés-González R. Calcitonin-Negative Neuroendocrine Carcinoma of the Thyroid Gland: Case Report and Literature Review. Case Rep Oncol 2021; 14:112-122. [PMID: 33776692 PMCID: PMC7983544 DOI: 10.1159/000510807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 08/07/2020] [Indexed: 11/24/2022] Open
Abstract
Calcitonin-negative neuroendocrine tumor (CNNET) of the thyroid is an extremely rare entity. In some of the previously reported cases within the literature, the terms “atypical medullary thyroid carcinoma,” “calcitonin-free oat cell carcinoma,” and “a distinct clinical entity” were applied to NETs without definitive evidence of calcitonin production. In the English-language literature, not only are there only few reported cases of CNNET, but the criteria for diagnosis in these cases are also controversial. Most of the current published cases were also treated surgically for local disease. We describe a case of NET of the thyroid with calcitonin, chromogranin A and thyroglobulin negativity, synaptophysin and TTF-1 positivity, and a high Ki-67 proliferation index with metastases in the cervical region as well as mediastinal adenopathies. This case was considered an unresectable thyroid carcinoma, and chemotherapy including cisplatin and etoposide was started as neoadjuvant treatment at the department of medical oncology. Total thyroidectomy plus bilateral and central cervical dissection was performed, and the patient underwent 2 cycles of adjuvant radiotherapy. Currently, the patient's <sup>18</sup>F-FDG-PET/CT findings show a complete response 17 months after diagnosis. In conclusion, CNNET of the thyroid is very rare and there is limited evidence regarding treatment in patients with metastases. Chemotherapy including cisplatin and etoposide as well as early aggressive surgical resection appears to positively impact patients' survival.
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Kopa P, Macieja A, Pastwa E, Majsterek I, Poplawski T. DNA double-strand breaks repair inhibitors potentiates the combined effect of VP-16 and CDDP in human colorectal adenocarcinoma (LoVo) cells. Mol Biol Rep 2021; 48:709-720. [PMID: 33389482 DOI: 10.1007/s11033-020-06124-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 12/22/2020] [Indexed: 12/18/2022]
Abstract
I. BACKGROUND A combination of etoposide (VP-16) and cisplatin (CDDP) is the standard treatment for certain colon cancers. These drugs promote the death of cancer cells via direct and indirect induction of the most lethal DNA lesions - DNA double-stand breaks. However, cancer cells can reverse the DNA damaging effect of anticancer drugs by triggering DNA repair processes. In eukaryotic cells, the main DNA repair pathway responsible for DNA double-stand breaks repair is non-homologous end-joining (NHEJ). Inhibitors of DNA repair are of special interest in cancer research as they could break the cellular resistance to DNA-damaging agents and increase the efficiency of standard cancer treatments. In this study, we investigated the effect of two NHEJ inhibitors, SCR7 and NU7441, on the cytotoxic mechanism of VP-16/CDDP in a LoVo human colorectal adenocarcinoma cell line. SCR7 blocks Ligase IV-mediated joining by interfering with its DNA binding, whereas NU7441 is a highly potent and selective DNA-PK inhibitor.II. METHODS AND RESULTS Both inhibitors synergistically increased the cytotoxicity of CDDP and VP-16 when combined, but the effect of SCR7 was more pronounced. SCR7 and NU7441 also significantly increased VP-16; CDDP induced DNA double-stand breaks level and delayed drug-induced DSB repair, as seen on the comet assay and measured using H2AX foci. We also observed changes in cell cycle distribution and enhanced apoptosis ratio in colorectal adenocarcinoma cells treated with DNA repair inhibitors and VP-16/CDDP.III. CONCLUSIONS Our data support the hypothesis that NHEJ inhibitors could be used in conjunction with standard therapy to provide effective clinical improvement and allow reduction in drug doses.
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R-CHOEP14 in younger high-risk patients with large B cell lymphoma: an effective front-line regimen with cardiac toxicity: a real-life, single-center experience. Ann Hematol 2020; 100:1517-1524. [PMID: 33216199 DOI: 10.1007/s00277-020-04353-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 11/17/2020] [Indexed: 10/23/2022]
Abstract
Currently, there is no consensus regarding optimal front-line treatment for younger high-risk patients with large B cell lymphoma. American recommendations list only R-CHOP as standard, while European also include R-ACVBP and R-CHOEP14. We have been routinely using the latter regimen at our institution since 2011 and performed this retrospective real-life single-center study to analyze outcomes. Between September 2011 and April 2019, 66 newly diagnosed patients aged 18 to 60 years with B-large cell lymphoma and high-risk age-adjusted International Prognostic Index score were scheduled to receive 6 or 8 cycles of bi-weekly chemoimmunotherapy with cyclophosphamide, doxorubicin, vincristine, etoposide, steroids, and rituximab (R-CHOEP14). After a median follow-up of 4.7 years, the estimated 3-year progression-free survival was 87% (95% CI 80-96%) and 3-year overall survival 90% (95% CI 83-98%). Grade ≥ 3 hematological side effects occurred in 83% and infectious in 41% of patients; one patient died of toxicity. Grade ≥ 2 cardiac toxicity occurred in 21% of patients, more frequently than previously reported. The cumulative 5-year risk of congestive heart failure with all-cause mortality as the competing risk was 17%. R-CHOEP14 is a very effective and manageable regimen for younger high-risk patients with B-large cell lymphoma, but the risk of cardiotoxicity warrants further investigations.
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Lovetrue B. The AI-discovered aetiology of COVID-19 and rationale of the irinotecan+ etoposide combination therapy for critically ill COVID-19 patients. Med Hypotheses 2020; 144:110180. [PMID: 33254502 PMCID: PMC7428675 DOI: 10.1016/j.mehy.2020.110180] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 04/21/2020] [Indexed: 02/06/2023]
Abstract
We present the AI-discovered aetiology of COVID-19, based on a precise disease model of COVID-19 built under five weeks that best matches the epidemiological characteristics, transmission dynamics, clinical features, and biological properties of COVID-19 and consistently explains the rapidly expanding COVID-19 literature. We present that SARS-CoV-2 implements a unique unbiased survival strategy of balancing viral replication with viral spread by increasing its dependence on (i) ACE2-expressing cells for viral entry and spread, (ii) PI3K signaling in ACE2-expressing cells for viral replication and egress, and (iii) viral- non-structural-and-accessory-protein-dependent immunomodulation to balance viral spread and viral replication. We further propose the combination of irinotecan (an in-market topoisomerase I inhibitor) and etoposide (an in-market topoisomerase II inhibitor) could potentially be an exceptionally effective treatment to protect critically ill patients from death caused by COVID-19-specific cytokine storms triggered by sepsis, ARDS, and other fatal comorbidities.
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Jha SK, Han HS, Subedi L, Pangeni R, Chung JY, Kweon S, Choi JU, Byun Y, Kim YH, Park JW. Enhanced oral bioavailability of an etoposide multiple nanoemulsion incorporating a deoxycholic acid derivative-lipid complex. Drug Deliv 2020; 27:1501-1513. [PMID: 33107339 PMCID: PMC7594851 DOI: 10.1080/10717544.2020.1837293] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
In this study, a system for oral delivery of etoposide (ETP) was designed to avoid the problems associated with low and variable bioavailability of a commercially available ETP emulsion comprised of polyethylene glycol, glycerol, and citric acid anhydrous. ETP was complexed with low-molecular-weight methylcellulose (ETP/LMC) and loaded into a water-in-oil-in-water multiple nanoemulsion to formulate an ETP/LMC-nanoemulsion (ELNE). To further enhance the oral bioavailability, an ionic complex formed by anionic lipid 1,2-didecanoyl-sn-glycero-3-phosphate (sodium salt) and cationic Nα-deoxycholyl-l-lysyl-methylester was incorporated into ELNE, yielding ELNE#7. As expected, ELNE#7 showed 4.07- and 2.25-fold increases in artificial membrane and Caco-2/HT29-MTX-E12 permeability (Papp), respectively, resulting in 224% greater oral bioavailability compared with the commercially available ETP emulsion. In contrast, inhibition of clathrin- and caveola-mediated endocytosis, macropinocytosis, and bile acid transporters by chlorpromazine, genistein, amiloride, and actinomycin D in Caco-2/HT-29-MTX-E12 monolayers reduced the Papp by 45.0%, 20.5%, 28.8%, and 31.1%, respectively. These findings suggest that these routes play important roles in enhancing the oral absorption of ELNE#7. In addition, our mechanistic study suggested that P-glycoprotein did not have an inhibitory effect on the permeation of ELNE#7. Notably, ELNE#7 showed significantly enhanced toxicity in LLC and A549 cells compared with ETP-E. These observations support the improved oral absorption of ETP in ELNE#7, suggesting that it is a better alternative than ETP emulsion.
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Dong Q, Zhou C, Ren H, Zhang Z, Cheng F, Xiong Z, Chen C, Yang J, Gao J, Zhang Y, Xu L, Fang J, Cao Y, Wei H, Wu Z. Lactate-induced MRP1 expression contributes to metabolism-based etoposide resistance in non-small cell lung cancer cells. Cell Commun Signal 2020; 18:167. [PMID: 33097055 PMCID: PMC7583203 DOI: 10.1186/s12964-020-00653-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 08/26/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Metabolic reprogramming contributes significantly to tumor development and is tightly linked to drug resistance. The chemotherapeutic agent etoposide (VP-16) has been used clinically in the treatment of lung cancer but possess different sensitivity and efficacy towards SCLC and NSCLC. Here, we assessed the impact of etoposide on glycolytic metabolism in SCLC and NSCLC cell lines and investigated the role of metabolic rewiring in mediating etoposide resistance. METHODS glycolytic differences of drug-treated cancer cells were determined by extracellular acidification rate (ECAR), glucose consumption, lactate production and western blot. DNA damage was evaluated by the comet assay and western blot. Chemoresistant cancer cells were analyzed by viability, apoptosis and western blot. Chromatin immunoprecipitation (ChIP) was used for analysis of DNA-protein interaction. RESULTS Here we showed that exposure to chemotherapeutic drug etoposide induces an exacerbation of ROS production which activates HIF-1α-mediated the metabolic reprogramming toward increased glycolysis and lactate production in non-small cell lung cancer (NSCLC). We identified lactic acidosis as the key that confers multidrug resistance through upregulation of multidrug resistance-associated protein 1 (MRP1, encoded by ABCC1), a member of ATP-binding cassette (ABC) transporter family. Mechanistically, lactic acid coordinates TGF-β1/Snail and TAZ/AP-1 pathway to induce formation of Snail/TAZ/AP-1 complex at the MRP1/ABCC1 promoter. Induction of MRP1 expression inhibits genotoxic and apoptotic effects of chemotherapeutic drugs by increasing drug efflux. Furthermore, titration of lactic acid with NaHCO3 was sufficient to overcome resistance. CONCLUSIONS The chemotherapeutic drug etoposide induces the shift toward aerobic glycolysis in the NSCLC rather than SCLC cell lines. The increased lactic acid in extracellular environment plays important role in etoposide resistance through upregulation of MRP expression. These data provide first evidence for the increased lactate production, upon drug treatment, contributes to adaptive resistance in NSCLC and reveal potential vulnerabilities of lactate metabolism and/or pathway suitable for therapeutic targeting. Video Abstract The chemotherapeutic drug etoposide induces metabolic reprogramming towards glycolysis in the NSCLC cells. The secreted lactic acid coordinates TGF-β1/Snail and TAZ/AP-1 pathway to activate the expression of MRP1/ABCC1 protein, thus contributing to chemoresistance in NSCLC.
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94
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All-oral metronomic DEVEC schedule in elderly patients with peripheral T cell lymphoma. Cancer Chemother Pharmacol 2020; 86:841-846. [PMID: 33070248 PMCID: PMC7568761 DOI: 10.1007/s00280-020-04172-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 10/06/2020] [Indexed: 11/20/2022]
Abstract
Purpose Peripheral T cell lymphomas (PTCLs) have an overall poor prognosis. Indeed, registry data in elderly patients show that the median progression-free survival (mPFS) following first- and second-line therapies are only 6.7 and 3.1 months, respectively. The aim of the study is to show the activity of metronomic chemotherapy, a regular administration of low chemotherapeutic drug doses allowing a favourable toxicity profile, on elderly PTCL patients. Methods We report a series of 17 PTCL patients, treated with the all-oral metronomic schedule DEVEC (prednisolone–etoposide–vinorelbine–cyclophosphamide) in four Italian centres. Patients 5/17 (29.4%) were treatment-naïve (naïve) and 12/17 (70.6%) were relapsed-refractory (RR), respectively. The median age was 83 years (range 71–87) and 71.5 years (range 56–85) for naïve and RR, respectively. In vitro activity of metronomic vinorelbine (VNR), etoposide (ETO) and their concomitant combination on HH, a PTCL cell line, was also assessed. Results Histology: PTCL-not-otherwise-specified = 12; angioimmunoblastic = 2; NK/T nasal type = 1; adult-type leukaemia lymphoma = 1, transformed Mycosis Fungoides = 1. The overall response rate was 80 and 58% in naïve and RR, respectively; whereas the PFS was 20 in naïve (95% CI 0–43) and 11 months (95% CI 4.2–17.8) in RR. The occurrence of relevant adverse events was 23.5%, which was managed with ETO dose reduction. In vitro experiments showed that both metronomic VNR and ETO caused a significant inhibitory activity on HH cells and a strong synergism when administered concomitantly. Conclusion All-oral DEVEC showed an encouraging activity and acceptable toxicity. This schedule deserves further studies in elderly PTCL also for assessing combinations with targeted drugs. Electronic supplementary material The online version of this article (10.1007/s00280-020-04172-3) contains supplementary material, which is available to authorized users.
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95
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Erkisa M, Ari F, Ulku I, Khodadust R, Yar Y, Yagci Acar H, Ulukaya E. Etoposide Loaded SPION-PNIPAM Nanoparticles Improve the in vitro Therapeutic Outcome on Metastatic Prostate Cancer Cells via Enhanced Apoptosis. Chem Biodivers 2020; 17:e2000607. [PMID: 32918383 DOI: 10.1002/cbdv.202000607] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/11/2020] [Indexed: 01/02/2023]
Abstract
Prostate cancer is among the leading causes of death worldwide because its metastatic form is a deadly disease. Therefore, the development of new chemotherapeutics is of immense importance. Nanoparticle technology seems to provide diverse options in this regard. Therefore, poly(N-isopropylacrylamide) (PNIPAM) coated superparamagnetic iron oxide nanoparticles (SPION) loaded with Etoposide were prepared in small sizes (57 nm) and with 3.5 % drug content to improve the efficiency of Etoposide in prostate cancer therapy. Sustained release of the drug was achieved, which found to be sensitive to low pH and high temperature. The anti-growth activity of SPION-PNIPAM-Etoposide formulation against metastatic prostate cancer cells (PC-3, LNCaP) were investigated by SRB assay, then, confirmed by ATP assay. Mode of cell death was evaluated by using flow cytometry analyses. A significant improvement of nanoformulated drug was observed at 5-10 μg/ml doses of the drug in both cell lines. More importantly, this formulation enhanced the cytotoxic effect of Etoposide on PC-3 cells, which is considered more resistant to Etoposide than LNCaP and reduced the IC50 value by 55 % reaching to 4.5 μg drug/ml, which is a very significant improvement in the literature. It was clearly shown that nanoformulated drug provided about 3-fold increases in caspase-dependent early apoptotic cells in PC-3 cells. The novel formulation seems to successfully cause cell death of especially PC-3 metastatic prostate cancer cells. It should therefore be taken into consideration for further animal studies as a novel potent anticancer agent.
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Wang B, Jiao N, Shi L. A case report of advanced gastric small cell carcinoma with neoadjuvant chemotherapy followed by radical total gastrectomy. Asian J Surg 2020; 43:1205-1206. [PMID: 33069575 DOI: 10.1016/j.asjsur.2020.09.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 09/24/2020] [Indexed: 11/28/2022] Open
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McCrorie P, Mistry J, Taresco V, Lovato T, Fay M, Ward I, Ritchie AA, Clarke PA, Smith SJ, Marlow M, Rahman R. Etoposide and olaparib polymer-coated nanoparticles within a bioadhesive sprayable hydrogel for post-surgical localised delivery to brain tumours. Eur J Pharm Biopharm 2020; 157:108-120. [PMID: 33068736 DOI: 10.1016/j.ejpb.2020.10.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 10/07/2020] [Accepted: 10/11/2020] [Indexed: 02/09/2023]
Abstract
Glioblastoma is a malignant brain tumour with a median survival of 14.6 months from diagnosis. Despite maximal surgical resection and concurrent chemoradiotherapy, reoccurrence is inevitable. To try combating the disease at a stage of low residual tumour burden immediately post-surgery, we propose a localised drug delivery system comprising of a spray device, bioadhesive hydrogel (pectin) and drug nanocrystals coated with polylactic acid-polyethylene glycol (NCPPs), to be administered directly into brain parenchyma adjacent to the surgical cavity. We have repurposed pectin for use within the brain, showing in vitro and in vivo biocompatibility, bio-adhesion to mammalian brain and gelling at physiological brain calcium concentrations. Etoposide and olaparib NCPPs with high drug loading have shown in vitro stability and drug release over 120 h. Pluronic F127 stabilised NCPPs to ensure successful spraying, as determined by dynamic light scattering and transmission electron microscopy. Successful delivery of Cy5-labelled NCPPs was demonstrated in a large ex vivo mammalian brain, with NCPP present in the tissue surrounding the resection cavity. Our data collectively demonstrates the pre-clinical development of a novel localised delivery device based on a sprayable hydrogel containing therapeutic NCPPs, amenable for translation to intracranial surgical resection models for the treatment of malignant brain tumours.
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Etoposide and topoisomerase II inhibition for aggressive prostate cancer: Data from a translational study. Cancer Treat Res Commun 2020; 25:100221. [PMID: 33091733 DOI: 10.1016/j.ctarc.2020.100221] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/05/2020] [Accepted: 10/04/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Etoposide phosphate (VP-16) is a topoisomerase 2 (TOP2) inhibitor that demonstrated activity in patients with metastatic castration-resistant prostate cancer (mCRPC). We investigated the sensitivity of prostate cancer (PCa) cells (LNCaP, 22Rv1, PC3, DU145, PDB and MDB) to VP-16 and the possible relationship between VP-16 activity and TOP2 expression. The activity of VP-16 was compared with that of docetaxel, enzalutamide and olaparib. The prevalence and clinical significance of TOP2 genetic and transcriptomic alterations was also explored in mCRPC. METHODS Cell cultures and crystal violet cell proliferation assays were performed. Specific antibodies were used in western blots analyses of cell protein extracts. Datasets were analyzed in cBioportal. RESULTS VP-16 was active in all PCa cell lines analyzed and demonstrated increased activity in PC3 and DU145 cells. VP-16 was more cytotoxic compared to the other treatments, except for LNCaP and 22Rv1, which were more sensitive to docetaxel. Maintenance of antiandrogen treatment in MDB and PDB increased sensitivity to VP-16, docetaxel and enzalutamide. TOP2A was found overexpressed in 22Rv1, DU145 and PC3, whereas TOP2B was overexpressed in 22Rv1 and PDB. In the mCRPC datasets analysis, TOP2A mRNA overexpression was associated with worse patients' prognosis, with the molecular features of neuroendocrine prostate cancer (NEPC) and with lower androgen receptor (AR) score. Patients overexpressing TOP2A mRNA were more likely to harbor RB1 loss. CONCLUSIONS Specific subpopulations of patients with aggressive variant prostate cancer (AVPC) could benefit from VP-16 treatment. TOP2A overexpression, rather than TOP2B, might be a good biomarker to predict response to VP-16.
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Using etoposide + dexamethasone-based regimens to treat nasal type extranodal natural killer/T-cell lymphoma-associated hemophagocytic lymphohistiocytosis. J Cancer Res Clin Oncol 2020; 147:863-869. [PMID: 33025280 PMCID: PMC7538035 DOI: 10.1007/s00432-020-03376-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/24/2020] [Indexed: 11/02/2022]
Abstract
PURPOSE Nasal type extranodal natural killer/T-cell lymphoma (ENKTL) can be associated with hemophagocytic lymphohistiocytosis (NK/T-LAHLH), which is a rare and fatal disease with no effective therapy. We evaluated whether etoposide + dexamethasone-based chemotherapy regimens might be useful for treating NK/T-LAHLH. METHODS This retrospective single-center study evaluated clinical data from 37 patients with NK/T-LAHLH who were treated between May 2008 and January 2020. RESULTS Among 363 patients with ENKTL, the cumulative incidence of HLH was 11.9%. Among 43 patients with NK/T-LAHLH, 37 patients received etoposide + dexamethasone-based chemotherapy regimens, with an overall response rate of 45.9% for the HLH. The overall response rate was substantially higher for newly diagnosed NK/T-LAHLH than it was for relapsed or refractory NK/T-LAHLH (66.7% vs. 18.8%). The median overall follow-up time was 4 months, with overall survival rates of 81.1% at 1 month, 62.2% at 2 months, 56.8% at 3 months, and 34.4% at 6 months. Significantly better overall survival (all P < 0.05) was observed for patients with newly diagnosed NK/T-LAHLH (vs. relapsed/refractory disease), stage I/II disease (vs. stage III/IV disease), and nasal disease (vs. non-nasal disease). Patients who responded to the ENKTL treatment also experienced response in their HLH; 8 patients experienced continued complete response for both HLH and ENKTL. Multivariate analysis revealed that a poor prognosis among patients with NK/T-LAHLH was independently related to relapsed/refractory ENKTL and non-nasal disease. CONCLUSION Although patients with NK/T-LAHLH generally experienced poor outcomes, etoposide + dexamethasone-based chemotherapy regimens were associated with good outcomes among select patients with newly diagnosed or stage I/II NK/T-LAHLH.
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Murphy MB, Kumar P, Bradley AM, Barton CE, Deweese JE, Mercer SL. Synthesis and evaluation of etoposide and podophyllotoxin analogs against topoisomerase IIα and HCT-116 cells. Bioorg Med Chem 2020; 28:115773. [PMID: 33035756 DOI: 10.1016/j.bmc.2020.115773] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 08/18/2020] [Accepted: 09/09/2020] [Indexed: 12/21/2022]
Abstract
Etoposide is a widely-used anticancer agent that targets human type II topoisomerases. Evidence suggests that metabolism of etoposide in myeloid progenitor cells is associated with translocations involved in leukemia development. Previous studies suggest halogenation at the C-2' position of etoposide reduces metabolism. Halogens were introduced into the C-2' position by electrophilic aromatic halogenation onto etoposide (ETOP, 1), podophyllotoxin (PPT, 2), and 4-dimethylepipodophyllotoxin (DMEP, 3), and to bridge the gap of knowledge regarding the activity of these metabolically stable analogs. Five halogenated analogs (6-10) were synthesized. Analogs 8-10 displayed variable ability to inhibit DNA relaxation. Analog 9 was the only analog to show concentration-dependent enhancement of Top2-mediated DNA cleavage. Dose response assay results indicated that 8 and 10 were most effective at decreasing the viability of HCT-116 and A549 cancer cell lines in culture. Flow cytometry with 8 and 10 in HCT-116 cells provide evidence of sub-G1 cell populations indicative of apoptosis. Taken together, these results indicate C-2' halogenation of etoposide and its precursors, although metabolically stable, decreases overall activity relative to etoposide.
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