Inhibitor Irinotecan Research Articles

The cell cycle inhibitor p21CIP1 is essential for irinotecan-induced senescence and plays a decisive role in re-sensitization of temozolomide-resistant glioblastoma cells to irinotecan

Background and purposeStandard of care for glioblastomas includes radio-chemotherapy with the monoalkylating compound temozolomide. Temozolomide induces primarily senescence, inefficiently killing glioblastoma cells. Recurrences are inevitable. Although recurrences presumably arise from cells evading/escaping TMZ-induced senescence, becoming resistant, they are often again treated with TMZ. As an alternative treatment, irinotecan could be used. Our aim was to examine to what extent and conditions the topoisomerase I inhibitor irinotecan induces senescence and to analyze the underlying mechanism. ResultsMultiple glioblastoma lines with different genetic signatures for p53, p21CIP1, p16INK4A, p14ARF, and PTEN were used. By means of LN229 glioblastoma clones which escaped from temozolomide-induced senescence, thus, being potentially recurrence-forming, we show that this escape is accompanied by increased p21CIP1 protein levels in temozolomide-unexposed senescence-evading clones and inability of temozolomide to induce p21CIP1. In contrast, irinotecan was still able to induce p21CIP1 and could elevate senescence and cell death. In combination with the senolytic drug BV6, irinotecan-induced senescence was significantly reduced. Differential response clusters were also observed in paired samples of newly diagnosed and recurrent patients’ tumors. This can partially explain a significantly prolonged progression-free time until surgery for recurrence in patients additionally treated with irinotecan after temozolomide consolidation and upon the first onset of recurrence. Conclusionsp21CIP1 is essentially involved in induction and maintenance of irinotecan-induced senescence. Neither p16INK4A, p14ARF, nor PTEN contribute to senescence, if p21CIP1 cannot be induced. Based on the positive results of the irinotecan/BV6 treatment, combatting recurrent glioblastomas by targeting senescence cell antiapoptotic pathways (SCAPs) should be considered.

Indolo[3,2-c]isoquinoline Hydroxamic Acid Derivatives as Novel Orally Topoisomerase-Histone Deacetylase Dual Inhibitors for NSCLC Therapy.

Based on the synergistic effects of topoisomerase (Top) inhibitors and histone deacetylase (HDAC) inhibitors in cancer therapy, a series of novel Top/HDAC dual inhibitors were designed and synthesized herein. The optimal compound 31 was identified to simultaneously inhibit both Tops and HDACs with potent antiproliferative activity against nonsmall cell lung cancer (NSCLC). Mechanistic studies indicated that compound 31 with increasing reactive oxygen species levels damages DNA, inhibiting cancer cell colony formation and migration and inducing both cancer cell apoptosis and cycle arrest. Noteworthily, compound 31 was orally active in the NSCLC xenograft model, and its antitumor efficacy (TGI = 77.5%, 100 mg/kg) was superior to that of HDAC inhibitor SAHA and SAHA in combination with the Top inhibitor irinotecan. Consequently, this work highlights the therapeutic potential of compound 31 as the Top/HDAC dual inhibitor in NSCLC therapy and provides valuable lead compounds for the further development of antitumor agents in solid tumor therapy.

Randomized Phase II Trial of Amrubicin Plus Irinotecan Versus Cisplatin Plus Irinotecan in Chemo-naïve Patients With Extensive-Disease Small-Cell Lung Cancer: Results of the Japan Multinational Trial Organization (JMTO) LC 08-01

BackgroundWe conducted a randomize phase II study to evaluate the efficacy and safety of topoisomerase II inhibitor amrubicin plus topoisomerase I inhibitor irinotecan (AI) compared with cisplatin plus irinotecan (PI) as first-line therapy in patients with extensive-disease (ED) small-cell lung cancer (SCLC). Patients and MethodsChemo-naïve patients with pathologically proven ED-SCLC (including limited disease (LD) SCLC with malignant effusion) were enrolled. Patients were randomized 1:1 to receive either AI (amrubicin 90mg/m2 on day 1 and irinotecan 50mg/m2 on days 1 and 8 of a 21-day cycle) or PI (cisplatin 60mg/m2 on day 1 and irinotecan 60mg/m2 on days 1, 8 and 15 of a 28-day cycle). The primary endpoint was overall survival proportion at 1 year. ResultsA total of 100 patients were randomly assigned to AI (n = 50) or to PI (n = 50). The 1-year overall survival proportions were 68.0% (95% confidence interval (CI): 56.2-82.2%) for AI and 59.2% (46.9-74.7%) for PI (1-sided P = .18). Median survival time was 14.8 months for AI and 13.5 months for PI with a hazard ratio (HR) of 0.618 (0.398-0.961, stratified log-rank test P = .031). Median progression-free survival time was 4.8 months for AI and 5.4 months for PI (stratified log-rank test, P = .54). Objective response rate was 70.0% (55.4-82.1%) for AI and 55.1% (40.2-69.3%) for PI (Fisher exact test, P = .15). There was no significant difference in hematological toxicity, whereas rates of vomiting, loss of appetite, diarrhea, and elevated serum creatinine are more frequent in PI. Interstitial lung disease (Grade 2 or 3) developed in 5 patients in AI and in 1 patient in PI. There was no treatment-related death. ConclusionAlthough the study did not meet its primary endpoint, AI showed promising efficacy and good tolerability in chemo-naïve patients with ED-SCLC.

Discovery of Indolo[3,2-c]isoquinoline Derivatives as Novel Top1/2 Dual Inhibitors with Orally Efficacious Antitumor Activity and Low Toxicity.

Topoisomerase (Top) inhibitors used in clinical cancer treatments are limited because of their toxicity and severe side effects. Noteworthily, Top1/2 dual inhibitors overcome the compensatory effect between Top1 and 2 inhibitors to exhibit stronger antitumor efficacies. In this study, a series of indolo[3,2-c]isoquinoline derivatives were designed as Top1/2 dual inhibitors possessing apparent antiproliferative activities. Mechanistic studies indicated that the optimal compounds 23 and 31 with increasing reactive oxygen species levels damage DNA, inducing both cancer cell apoptosis and cycle arrest. Importantly, the results of the toxicity studies showed that compounds 23 and 31 possessed good oral safety profiles. In xenograft models, compound 23 exhibited remarkable antitumor potency, which was superior to the clinical Top inhibitors irinotecan and etoposide. Overall, this work highlights the therapeutic potential and safety profile of compound 23 as a Top1/2 dual inhibitor in tumor therapy and provides valuable lead compounds for further development of Top inhibitors.

SACI-IO HR+: A randomized phase II trial of sacituzumab govitecan with or without pembrolizumab in patients with metastatic hormone receptor-positive/HER2-negative breast cancer.

LBA1004 Background: Sacituzumab govitecan (SG) is a TROP2 antibody drug conjugate (ADC) with a topoisomerase I inhibitor payload (SN-38) approved for previously treated triple negative and hormone receptor-positive/HER2-negative (HR+/HER2-) metastatic breast cancer (MBC). Double-strand DNA breaks induced by SN-38 activate cGAS-STING, stimulating type I IFN production and T cell recruitment. SN-38 can upregulate MHC class-I and PD-L1 expression, enhance cytotoxic T cell effector functions and deplete regulatory T cells. To evaluate if SG synergizes with pembrolizumab (PD-1 inhibitor) we conducted a randomized, open-label phase 2 study comparing SG with or without pembrolizumab in HR+/HER2- MBC (NCT04448886). Methods: Eligible patients (pts) had unresectable locally advanced or metastatic HR+ (ER≥1% and/or PR≥1%), HER2- breast cancer treated with ≥1 prior endocrine therapy and 0-1 chemotherapy (CT) for MBC. Pts with brain metastases were eligible if locoregional therapy was completed and steroids discontinued ≥7 days before study therapy. Pts who received prior topoisomerase I inhibitor ADC, irinotecan or PD-1/L1 inhibitors were excluded. Pts were randomized 1:1 to Arm A [SG 10 mg/kg IV (D1, D8) + pembrolizumab 200 mg IV (D1), 21-day cycle] or Arm B (SG alone). The primary endpoint was progression-free survival (PFS); secondary endpoints included PFS in PD-L1+ pts (22C3 CPS ≥1), overall survival (OS), objective response rate (ORR) and toxicity (NCI CTCAE v5.0). Baseline and on-treatment biopsies were performed for correlative analyses. For this preliminary analysis, data were locked 1/12/24. Results: Between 03/2021-01/2024, 110 pts enrolled; 104 pts (52 Arm A; 52 Arm B) started study therapy and were included in the analysis. Median age was 57 yrs (range: 27-81); 102 pts (98.1%) were female. 80 pts (76.9%) received prior CDK4/6 inhibitor for MBC; 58 (55.8%) had no prior CT, 46 (44.2%) had 1 prior line of CT for MBC. At a median follow-up of 9.2 months (mo), median PFS was 8.4 mo in Arm A vs 6.2 mo in Arm B (HR 0.76, 95% CI 0.47-1.23, log-rank p=0.26); ORR 21.2% and 17.3%, respectively. OS data are immature with only 26 events to date; OS was 16.9 mo vs 17.1 mo (HR 0.65, 95% CI 0.30-1.41, log-rank p=0.28), respectively. The most frequent treatment-related toxicities (≥G2) in Arm A were neutropenia (67.3%), fatigue (36.5%), alopecia (36.5%), anemia (32.7%), leukopenia (26.9%), diarrhea (21.2%) and nausea (21.2%); in Arm B, neutropenia (59.6%), alopecia (38.5%), diarrhea (34.6%), nausea (32.7%), fatigue (32.7%) and anemia (21.2%). Conclusions: Addition of pembrolizumab to SG showed a non-significant trend toward improved PFS in unselected HR+/HER2- MBC at this preliminary time point. Final PFS and updated OS with further follow-up will be presented at the meeting. Exploratory outcome analyses by TROP2 and PD-L1 expression will be reported. Clinical trial information: NCT04448886 .

A phase I study of irinotecan combined with BAY1895344 (ATR inhibitor) in advanced solid tumors: Results of ETCTN 10402 dose escalation.

3077 Background: ATR protein kinase is activated by replication stress and recruited to stalled forks or single strand DNA defects in various cancers. The topoisomerase-I (Top1) inhibitor irinotecan induces DNA damage. The ATR inhibitor BAY1895344 (elimusertib) has demonstrated cytotoxic potential in SCLC and GI cancer xenografts when combined with Top1 inhibitors . Methods: This phase Ia trial assessed elimusertib in combination with irinotecan in adult patients with refractory advanced solid tumors for whom irinotecan can be considered standard care. Patients with previous irinotecan exposure were excluded. Two dosing schedules were used: 1) Biweekly - irinotecan IV (starting at 150 mg/m2) D1 + elimusertib (starting dose 20 mg PO BID) D1,D2 (cycle=14 days); 2) Weekly - irinotecan (starting at 50 mg/m2) IV on D1,8,15 with elimusertib (starting at 20 mg PO daily) on D2,D3,D9,D10 and D16,D17 (cycle=21 days). Dose escalation utilized a 3+3 design. Primary objectives were to assess safety and tolerability and estimate the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D). Secondary objectives included estimating pharmacokinetic (PK) profiles and assessing anti-tumor activity. Results: A total of 21 patients were enrolled in dose escalation (N=9 [Biweekly] and N=12 [Weekly], median age 58 and 2 lines of prior therapy. For the Biweekly cohort: 3/3 patients enrolled at dose level (DL) 1 experienced hematologic dose-limiting toxicity (DLT); 6 patients received DL-1 without any DLTs. The weekly regimen escalation comprised of 12 patients: 6 enrolled in DL1 with 2/6 having hematologic DLT and 5/6 unable to complete ≥75% of cycle 1 dosing; 6 enrolled in DL-1 with no DLTs observed. Notable grade 3+ treatment-related adverse events and summary best response are summarized (Table 1). The majority of evaluable patients in both schedules had initial disease control (56% [biweekly] and 67% [weekly]). One confirmed partial response was seen in the biweekly RP2D. Median progression-free survival was 2.1 mo [biweekly] and 2.5 mo [weekly]. PK results will be presented at time of meeting. Conclusions: Both RP2D and MTD of elimusertib in combination with irinotecan were reached for both dosing schedules: irinotecan 150 mg/m2 IV D1 + elimusertib 10 mg BID PO D1,D2 (biweekly) and irinotecan 25 mg/m2 IV on D1 + elimusertib (20 mg PO daily) on D2,D3 (weekly). Dose escalation was notably limited by myelotoxicity. Due to sponsor decision, the study was halted prior to planned expansion but the concept of ATR + topo I combination remains scientifically relevant. Clinical trial information: NCT04514497 . [Table: see text]

Abstract PO1-05-09: ASCENT-07: A phase 3, randomized, open-label study of sacituzumab govitecan versus treatment of physician’s choice in patients with HR+/HER2– inoperable, locally advanced, or metastatic breast cancer post-endocrine therapy

Abstract Background: Approximately 70% of all breast cancer (BC) cases are hormone receptor positive/human epidermal growth factor receptor 2-negative (HR+/HER2–), with ~65% of these being HR+/HER2-low (immunohistochemistry [IHC]1+, IHC2+/in situ hybridization [ISH]–). Despite an increasing number of available endocrine and targeted treatments for metastatic disease, tumors eventually develop resistance to endocrine therapy (ET). Chemotherapy, the standard of care for patients (pts) whose cancers no longer respond to ET, is associated with poor outcomes, representing a high unmet need in the first-line endocrine-resistant setting. Sacituzumab govitecan (SG) is a Trop-2–directed antibody-drug conjugate (ADC) that delivers SN-38 (the active metabolite of the topoisomerase inhibitor irinotecan) to tumor cells via internalization, and to the surrounding tumor microenvironment via the bystander effect. SG demonstrated a significant and clinically meaningful survival benefit in the phase 3, randomized TROPiCS-02 trial, and is approved in the US for inoperable, locally advanced, or metastatic HR+/HER2– BC after ET and ≥ 2 systemic therapies in the metastatic setting. ASCENT-07 will examine the efficacy and safety of SG in the first-line chemotherapy setting, ie, in patients with inoperable, locally advanced, or metastatic ET resistant HR+/HER2– BC. Study design: ASCENT-07 (NCT05840211) is a randomized, open-label, global study evaluating SG versus treatment of physician’s choice (TPC) chemotherapy in pts with HR+/HER2– inoperable, locally advanced, or metastatic BC who have received ET and are eligible for their first chemotherapy for advanced/metastatic disease. Pts aged ≥ 18 years with histologically confirmed HR+/HER2– (HER2 IHC0 or HER2-low [IHC1+, IHC2+/ISH–]) according to ASCO/CAP criteria, measurable disease per RECIST v1.1, and ECOG performance status of 0 or 1 will be included. Pts are eligible if they meet ≥ 1 of the following criteria: progressive disease (PD) in the metastatic setting on ≥ 2 lines of ET (± targeted therapy) (disease recurrence within the first 24 months of starting adjuvant ET is considered a line of therapy), PD within 6 months of first-line ET (± CDK 4/6 inhibitor) in the metastatic setting, or disease recurrence within 24 months of adjuvant ET with CDK 4/6 inhibitor initiation and no longer a candidate for additional ET. PD on the most recent therapy will be documented by CT or MRI per RECIST v1.1. Key exclusion criteria include prior treatment targeting topoisomerase I. Pts will be randomized to SG 10 mg/kg IV on days 1 and 8 of a 21-day cycle or TPC (capecitabine, paclitaxel, nab-paclitaxel). The primary endpoint is progression-free survival (PFS) assessed by blinded independent central review (BICR) per RECIST v1.1 criteria or death from any cause, whichever comes first. Secondary endpoints include PFS (assessed by the investigator), overall survival, objective response rate and duration of response per BICR and investigator, and quality of life (QoL) assessed using the EORTC QLQ-C30 cancer questionnaire (primarily change in the Physical Functioning domain at week 16 and time to deterioration in the Global Health Status/QoL domain). Pharmacokinetics and immunogenicity analyses will be undertaken in pts receiving SG. Incidence of adverse events and serious adverse events, including relationship to study drug(s), will be reported. Laboratory and vital signs will be monitored. ASCENT-07 is currently open for recruitment and requires ~654 eligible pts to provide adequate power for assessment of the primary and key secondary endpoints. Citation Format: Hope Rugo, Javier Cortés, Giuseppe Curigliano, Carlos Barrios, Kevin Punie, Yeon Park, Hiroji Iwata, Alex Young, Xuehan Ren, Pelin Cinar, Komal Jhaveri. ASCENT-07: A phase 3, randomized, open-label study of sacituzumab govitecan versus treatment of physician’s choice in patients with HR+/HER2– inoperable, locally advanced, or metastatic breast cancer post-endocrine therapy [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-05-09.

Minocycline and photodynamic priming significantly improve chemotherapy efficacy in heterotypic spheroids of pancreatic ductal adenocarcinoma

The prognosis for patients with advanced-stage pancreatic ductal adenocarcinoma (PDAC) remains dismal. It is generally accepted that combination cancer therapies offer the most promise, such as Folforinox, despite their associated high toxicity. This study addresses the issue of chemoresistance by introducing a complementary dual priming approach to attenuate the DNA repair mechanism and to improve the efficacy of a type 1 topoisomerase (Top1) inhibitor. The result is a regimen that integrates drug-repurposing and nanotechnology using 3 clinically relevant FDA-approved agents (1) Top1 inhibitor (irinotecan) at subcytotoxic doses (2) benzoporphyrin derivative (BPD) as a photoactive molecule for photodynamic priming (PDP) to improve the delivery of irinotecan within the cancer cell and (3) minocycline priming (MNP) to modulate DNA repair enzyme Tdp1 (tyrosyl-DNA phosphodiesterase) activity. We demonstrate in heterotypic 3D cancer models that incorporate cancer cells and pancreatic cancer-associated fibroblasts that simultaneous targeting of Tdp1 and Top1 were significantly more effective by employing MNP and photoactivatable multi-inhibitor liposomes encapsulating BPD and irinotecan compared to monotherapies or a cocktail of dual or triple-agents. These data are encouraging and warrant further work in appropriate animal models to evolve improved therapeutic regimens.

УЧЕТ ИНДЕКСА КОМОРБИДНОСТИ ПРИ ПРОВЕДЕНИИ ПРОТИВООПУХОЛЕВОЙ ЛЕКАРСТВЕННОЙ ТЕРАПИИ У ПАЦИЕНТОВ ПОЖИЛОГО И СТАРЧЕСКОГО ВОЗРАСТА С КОЛОРЕКТАЛЬНЫМ РАКОМ (ОБЗОР ЛИТЕРАТУРЫ)

The problem of treating elderly patients is one of the most pressing in modern clinical medicine. Colorectal cancer is one of the main causes of mortality from malignant neoplasms in Russia and other developed countries. At the same time, the incidence of tumors of the colon and rectum steadily increases with age. Before starting treatment for elderly patients, it is necessary to carefully weigh the potential risks and the possibility of achieving positive results of antitumor therapy. Objective: To summarize the literature on the use of a comprehensive geriatric assessment, including the Cancer and Aging Research Group (CARG) toxicity assessment, to predict the risk of adverse events during anticancer drug treatment in elderly patients diagnosed with colorectal cancer. Materials and methods: The search for scientific sources was carried out in PubMed / Medline / UpToDate using the following keywords: “malignant tumors”, “metastatic colorectal cancer”, “senile age”, “antitumor drug therapy”. The time horizon covered 2016–2023. Using a time filter, the most relevant and innovative research papers on the issues of chemotherapy treatment of elderly and senile patients were selected. Results: Most current evidence demonstrates the importance of performing a comprehensive geriatric assessment (CGA), Cancer and Aging Research Group (CARG) toxicity assessment in elderly and geriatric patients. Information obtained from geriatric assessment should be used to predict and manage treatment toxicity. And also for assessing and predicting overall survival. Activities based on CGA can reduce the toxicity of chemotherapy, improve the quality of life of patients, and increase compliance with medical recommendations. Undoubtedly, a comprehensive geriatric assessment (CGA) can help achieve the necessary balance between the potential effectiveness and adverse events of chemotherapy. The choice of treatment tactics for an elderly and senile cancer patient should be based on the patient’s functional status (PS), general somatic status according to the ECOG scale, and the risk of toxicity according to the CARG scale. In the presence of colorectal cancer, patients with good functional status who need antitumor systemic effects can be prescribed polychemotherapy with FOLFOX, XELOX, FOLFIRI doublets with the addition of targeted drugs: bevacizumab or cetuximab (depending on the results of gene profiling of the tumor). Patients who are not candidates for polychemotherapy in standard doses, who have a general somatic status on the ECOG scale of 1-2 and an average risk of developing toxicity of grade 3 on the CARG scale, can undergo PCT with FOLFOX, XELOX, FOLFIRI doublets with a reduction in the starting dose by 20%, or monochemotherapy with antimetabolites: capecitabine, 5-fluorouracil; topoisomerase I inhibitor irinotecan. Patients with poor functional status, general somatic status on the ECOG scale 3-4, and a high risk of developing toxicity on the CARG scale are not candidates for systemic combination chemotherapy. Particular attention should be paid to maintenance therapy in this subgroup of patients. However, if the decrease in PS level is directly related to malignancy and PS ≥2, the possibility of monochemotherapy by infusion of a combination of 5-fluorouracil and leucovorin FU/LV can be evaluated.

Abstract 674: Novel anti-cancer small molecule targeting the protein regulator of cytokinesis pathway

Abstract Aberrant migration and proliferation of cancer cells are the hallmark of metastatic tumors. Protein Regulator of Cytokinesis 1 (PRC1) is a scaffold protein that regulates metabolic pathways of cancer cell proliferation, survival, and metastasis. BKT300 is a small molecule (MW 399.33, C22H25NO6), that selectively inhibits the migration and survival of hematological and solid cancer cells. BKT300 inhibits, at high affinity, both actin and microtubule formation and organization leading to G2/M cell cycle arrest, mitotic catastrophe, and apoptosis through the caspase 3 pathway. These effects are selective to cancer cells and were not observed on normal cells. BKT300 was found to arrest PRC1 in a phosphorylated form at position T481, down regulates the expression of CDC25C and up regulate p21. Suppression of PRC1 using SiRNA ablation inhibited BKT300 induced apoptosis on several tumor cell lines and inhibited the effect of BKT300 on G2M cell cycle arrest. Furthermore, using Biacore SPR, microscale thermophoresis (MST), and ELISA assays we were able to demonstrate the direct binding of BKT300 to PRC1. Beyond its single agent activity, BKT300 was shown to synergize with standard of care (SoC) treatments, including anti PD-1 immunotherapy, BCL-2 inhibitor (Ventoclax), topoisomerase I inhibitor (Irinotecan) topoisomerase II inhibitor (Doxorubicin), anti-metabolite Fluorouracil (5-FU) and alkylating agent (Temozolomide). BKT300 has a remarkable safety profile when administered at high doses to mice rats, minipigs and non-human primates. Treatment with BKT300 showed almost no effects on hematopoiesis and biochemistry in doses far higher than the affective ones. The in-vivo activity of BKT300 was demonstrated in multiple Xenograft, Syngeneic and PDX models in mice. In-vivo treatment with BKT300 resulted in preventive (small tumors) as well as therapeutic (large tumors) activity in triple negative breast cancer (TNBC) xenograft, MDA-MB-453 and MDA-MB-468 models leading to over then 70%-90% reduction in tumor size following one to two treatments cycles. Similar results were obtained using PDX models derived from patients with Colon, Ovarian and Pancreatic cancer. BKT300 is a novel, first in class, targeted anti-cancer treatment that inhibits the activity of the scaffold protein PRC1. BKT300 is expected to provide a new treatment option to, the high unmet medical need of, advanced difficult to treat cancers, specifically ones that overexpress PRC1 and CDC25C. Citation Format: Amnon Peled, Michal Abraham, Hanna Wald, Rakefet Rosenfeld, Orly Eizenberg, Arnon Aharon. Novel anti-cancer small molecule targeting the protein regulator of cytokinesis pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 674.

Tapcin, an In Vivo Active Dual Topoisomerase I/II Inhibitor Discovered by Synthetic Bioinformatic Natural Product (Syn-BNP)-Coupled Metagenomics.

DNA topoisomerases are attractive targets for anticancer agents. Dual topoisomerase I/II inhibitors are particularly appealing due to their reduced rates of resistance. A number of therapeutically relevant topoisomerase inhibitors are bacterial natural products. Mining the untapped chemical diversity encoded by soil microbiomes presents an opportunity to identify additional natural topoisomerase inhibitors. Here we couple metagenome mining, bioinformatic structure prediction algorithms, and chemical synthesis to produce the dual topoisomerase inhibitor tapcin. Tapcin is a mixed p-aminobenzoic acid (PABA)-thiazole with a rare tri-thiazole substructure and picomolar antiproliferative activity. Tapcin reduced colorectal adenocarcinoma HT-29 cell proliferation and tumor volume in mouse hollow fiber and xenograft models, respectively. In both studies it showed similar activity to the clinically used topoisomerase I inhibitor irinotecan. The study suggests that the interrogation of soil microbiomes using synthetic bioinformatic natural product methods has the potential to be a rewarding strategy for identifying potent, biomedically relevant, antiproliferative agents.

Tapcin, an In Vivo Active Dual Topoisomerase I/II Inhibitor Discovered by Synthetic Bioinformatic Natural Product (Syn‐BNP)‐Coupled Metagenomics

AbstractDNA topoisomerases are attractive targets for anticancer agents. Dual topoisomerase I/II inhibitors are particularly appealing due to their reduced rates of resistance. A number of therapeutically relevant topoisomerase inhibitors are bacterial natural products. Mining the untapped chemical diversity encoded by soil microbiomes presents an opportunity to identify additional natural topoisomerase inhibitors. Here we couple metagenome mining, bioinformatic structure prediction algorithms, and chemical synthesis to produce the dual topoisomerase inhibitor tapcin. Tapcin is a mixed p‐aminobenzoic acid (PABA)‐thiazole with a rare tri‐thiazole substructure and picomolar antiproliferative activity. Tapcin reduced colorectal adenocarcinoma HT‐29 cell proliferation and tumor volume in mouse hollow fiber and xenograft models, respectively. In both studies it showed similar activity to the clinically used topoisomerase I inhibitor irinotecan. The study suggests that the interrogation of soil microbiomes using synthetic bioinformatic natural product methods has the potential to be a rewarding strategy for identifying potent, biomedically relevant, antiproliferative agents.

Treatment with novel topoisomerase inhibitors in Ewing sarcoma models reveals heterogeneity of tumor response.

The topoisomerase 1 (TOP1) inhibitor irinotecan is a standard-of-care agent for relapsed Ewing sarcoma (EWS), but its efficacy is limited by chemical instability, rapid clearance and reversibility, and dose-limiting toxicities, such as diarrhea. Indenoisoquinolines (IIQs) represent a new class of clinical TOP1 inhibitors designed to address these limitations. In this study, we evaluated the preclinical efficacy of three IIQs (LMP400, LMP744, and LMP776) in relevant models of EWS. We characterized the pharmacokinetics of IIQs in orthotopic xenograft models of EWS, optimized the dosing regimen through tolerability studies, and tested the efficacy of IIQs in a panel of six molecularly heterogeneous EWS patient-derived xenograft (PDX) models. For each PDX, we conducted whole genome and RNA sequencing, and methylation analysis. We show that IIQs potently inhibit the proliferation of EWS cells in vitro, inducing complete cell growth inhibition at nanomolar concentrations via induction of DNA damage and apoptotic cell death. LMP400 treatment induced ≥30% tumor regression in two of six PDX models, with more durable regression compared to irinotecan treatment in one of these models. RNA sequencing of PDX models identified a candidate predictive biomarker gene signature for LMP400 response. These data, along with pharmacogenomic data on IIQs in sarcoma cell lines, are available at a new interactive public website: https://discover.nci.nih.gov/rsconnect/EwingSarcomaMinerCDB/. Our findings suggest that IIQs may be promising new agents for a subset of EWS patients.

Increased binding of anti-dsDNA antibodies to short oligonucleotides modified with topoisomerase I reveals a potential new enzyme function independent from DNA relaxation

ObjectiveTopoisomerase I (topo I) is a highly conserved enzyme which is known to reduce torsional stress at double-stranded (ds) DNA. Torsional stress induced by supercoiling of dsDNA requires either very long dsDNA existing in genomic DNA or circulation as presented in plasmid DNA. To enable DNA relaxation, topo I induce a transient single-strand break followed by stress-relieving rotation of the released DNA strand. Our group found by serendipity that the topo I inhibitor irinotecan is able to suppress murine systemic lupus erythematosus (SLE), an autoimmune disease which is characterized by the existence of pathogenic anti-dsDNA antibodies (abs). As a possible mechanism we demonstrated in the absence of immunosuppression an increased binding of anti-dsDNA abs to long genomic or circulated plasmid dsDNA modified with topo I.ResultsHere we show that this effect requires active site tyrosine of topo I which is known to facilitate DNA relaxation activity. Moreover, topo I enhanced anti-dsDNA abs binding to short linear oligonucleotides down to a size of 42 bp. Since oligonucleotides of such length are devoid of torsional stress and relaxation respectively, our results suggest a new and unknown function for the enzyme topo I.

Role of Lactobacillus and calcium in colorectal cancer

Colorectal cancer (CRC) is the third most cancer which is prevalent globally. It is the second most leading cause of mortality worldwide. In Asia Colorectal cancer is most abundant type of cancer. Causative factors involved are genetic pattern, western lifestyle, alcohol, smoking, etc. The commonest therapy for colorectal cancer is the combination therapy of 5-fluorouracil with Leucovorin which is either co-administered with alkylating agent Oxaliplatin or with a topoisomerase inhibitor Irinotecan. There is still a need of therapeutic agent that increases the survival rate in colorectal cancer patients. Probiotics are well known to increase the proliferation of beneficial bacteria and recently they are widely researched for regression of carcinogenesis. a commonly used probiotic, is observed to increase the expression of apoptotic ligand by modulating TNF action. has also shown to represses cyclin D1 and inhibit the Wnt/β-catenin signaling thereby, not only prevent the proliferation of cancerous cells but also ensure the apoptosis of CRC cells. Calcium is a vital element in many biological pathways including cancer signaling pathway. A wide variety of research reflects the role of calcium in suppression of cancerous cells. Recently calcium has shown its role in inhibiting Wnt/-catenin signaling canonical pathway in colorectal cancer cells. The review focuses on the role of calcium and probiotic as a natural therapeutic option in the treatment of CRC.

IN SILICO MOLECULAR SCREENING AND DOCKING APPROACHES ON ANTINEOPLASTIC AGENT-IRINOTECAN TOWARDS THE MARKER PROTEINS OF COLON CANCER

Objective: The present investigation explores the binding affinities of Irinotecan, which is a topoisomerase I inhibitor, against the targets such as AKT1, TNKS-2, MMP, EGFR, TNKS-1, and BRAF, which are the protein that was overexpressed by colorectal carcinogenesis. Methods: In this study, the drug structure was drawn by chemdraw software and explored for its anti-cancer potential by Schrodinger software against selected targeted proteins such as epidermal growth factor receptor (EGFR), matrix metalloproteinase (MMPs), serine/threonine protein kinase Ba (AKT1), BRAF, tankyrases 1 (TNKS-1, and tankyrases 2 (TNKS-2). Results: From the results of docking analysis, the targets with the maximum binding affinity towards the preselected drug Irinotecan were further subjected to ADME prediction by the QikProp module of Schrodinger Maestro version 2018.4. Molecular docking analysis revealed that surface protein targets AKT1, TNKS-2, MMP, and EGFR have the highest binding affinity towards the selected topoisomerase I inhibitor Irinotecan when compared to TNKS-1 and BRAF targets. The higher docking score of Irinotecan with extracellular colorectal cancer target proteins was discovered in this investigation. Conclusion: Cancer is one of the most prevalent, lethal and risky malignant pathologies with an elevated prevalence and mortality rate worldwide. The current work will be more beneficial for rationalising the effective anticancer treatment according to the intensities of expression of the colon cancer target protein and for creating an optimum targeted drug delivery system of an anticancer agent to treat colon cancer.

Targeting neddylation sensitizes colorectal cancer to topoisomerase I inhibitors by inactivating the DCAF13-CRL4 ubiquitin ligase complex

Colorectal cancers (CRCs) are prevalent worldwide, yet current treatments remain inadequate. Using chemical genetic screens, we identify that co-inhibition of topoisomerase I (TOP1) and NEDD8 is synergistically cytotoxic in human CRC cells. Combination of the TOP1 inhibitor irinotecan or its bioactive metabolite SN38 with the NEDD8-activating enzyme inhibitor pevonedistat exhibits synergy in CRC patient-derived organoids and xenografts. Mechanistically, we show that pevonedistat blocks the ubiquitin/proteasome-dependent repair of TOP1 DNA-protein crosslinks (TOP1-DPCs) induced by TOP1 inhibitors and that the CUL4-RBX1 complex (CRL4) is a prominent ubiquitin ligase acting on TOP1-DPCs for proteasomal degradation upon auto-NEDD8 modification during replication. We identify DCAF13, a DDB1 and Cullin Associated Factor, as the receptor of TOP1-DPCs for CRL4. Our study not only uncovers a replication-coupled ubiquitin-proteasome pathway for the repair of TOP1-DPCs but also provides molecular and translational rationale for combining TOP1 inhibitors and pevonedistat for CRC and other types of cancers.

Effect and mechanism of apelin on lipopolysaccharide induced acute pulmonary vascular endothelial barrier dysfunction

Vascular endothelial barrier dysfunction is the most prominent manifestation and important cause of mortality in infectious acute lung injury (ALI). Exogenous apelin is effective in ameliorating lipopolysaccharide (LPS)-induced inflammatory response in ALI lungs, reducing exudation of lung tissue and decreasing mortality. This study set out to investigate the association between apelin and Friend leukemia integration-1 (Fli-1) in the prevention and treatment of ALI, and to elucidate the molecular mechanism by which apelin protects the permeability of the vascular endothelial barrier. At the vivo functional level, lung wet/dry weight ratio was used to detect whole lung permeability, evans blue assay and dual fluorescent protein tracking assay were used to detect lung vascular endothelial permeability, HE staining to observe the inflammatory status of lung tissue, and immunofluorescence staining for VE-cadherin expression levels in blood vessels. The changes in inflammatory factors in bronchoalveolar lavage fluid (BALF) were detected by ELASA. Western blot was used to detect the expression level of proteins. qRT-PCR was performed to detect changes in mRNA expression of Fli-1 and adherent junction-related proteins. The correlation analysis of Fli-1 with vascular endothelial permeability and SRC showed that Fli-1 participated in the process of ALI. After preventive and therapeutic treatment of ALI mice with exogenous apelin, Fli-1, APJ, VE-cadherin, phosphorylated-VE-cadherin (p-VE-cadherin) and β-catenin were up-regulated, while SRC, phosphorylated-SRC (p-SRC), VEGF and VEGF-R were down-regulated, which indicated that the stability of vascular endothelial barrier was enhanced. With the use of Fli-1 inhibitor irinotecan, the protective effect of apelin was weakened in various functional indexes, genes and proteins. The lung was maintained at the level of the injury. Our research shows that Fli-1 is involved in the LPS-induced ALI process. The molecular mechanism for apelin in preventing endothelial barrier dysfunction in ALI is through up-regulating Fli-1, thus regulating adherens junction-related proteins, and finally recovering the endothelial barrier function.

The Interactions of the 70 kDa Fragment of Cell Adhesion Molecule L1 with Topoisomerase 1, Peroxisome Proliferator-Activated Receptor γ and NADH Dehydrogenase (Ubiquinone) Flavoprotein 2 Are Involved in Gene Expression and Neuronal L1-Dependent Functions.

The cell adhesion molecule L1 is essential not only for neural development, but also for synaptic functions and regeneration after trauma in adulthood. Abnormalities in L1 functions cause developmental and degenerative disorders. L1's functions critically depend on proteolysis which underlies dynamic cell interactions and signal transduction. We showed that a 70 kDa fragment (L1-70) supports mitochondrial functions and gene transcription. To gain further insights into L1-70's functions, we investigated several binding partners. Here we show that L1-70 interacts with topoisomerase 1 (TOP1), peroxisome proliferator-activated receptor γ (PPARγ) and NADH dehydrogenase (ubiquinone) flavoprotein 2 (NDUFV2). TOP1, PPARγ and NDUFV2 siRNAs reduced L1-dependent neurite outgrowth, and the topoisomerase inhibitors topotecan and irinotecan inhibited L1-dependent neurite outgrowth, neuronal survival and migration. In cultured neurons, L1 siRNA reduces the expression levels of the long autism genes neurexin-1 (Nrxn1) and neuroligin-1 (Nlgn1) and of the mitochondrially encoded gene NADH:ubiquinone oxidoreductase core subunit 2 (ND2). In mutant mice lacking L1-70, Nrxn1 and Nlgn1, but not ND2, mRNA levels are reduced. Since L1-70's interactions with TOP1, PPARγ and NDUFV2 contribute to the expression of two essential long autism genes and regulate important neuronal functions, we propose that L1 may not only ameliorate neurological problems, but also psychiatric dysfunctions.

Anti-Colorectal Cancer Effects of a Novel Camptothecin Derivative PCC0208037 In Vitro and In Vivo

Colorectal cancer is one of the most common malignancies, and the topoisomerase inhibitor irinotecan (CPT-11)-based chemotherapeutic regimen is currently the first-line treatment with impressive therapeutic efficacy. However, irinotecan has several clinically significant side effects, including diarrhea, which limit its clinical utility and efficacy in many patients. In an effort to discover better and improved pharmacotherapy against colorectal cancer, we synthesized a novel topoisomerase inhibitor, PCC0208037, examined its anti-tumor efficacy and related molecular mechanisms, and characterized its toxicity and pharmacokinetic profiles. PCC0208037 suppressed colorectal cancer cell (CRC) proliferation and increased cell cycle arrest, which may be related to its effects on up-regulating DNA damage response (DDR)-related molecules and apoptosis-related proteins. PCC0208037 demonstrated robust anti-tumor activity in vivo in a colorectal cancer cell xenograft model, which was comparable to or slightly better than CPT-11. In a preliminary toxicology study, PCC0208037 demonstrated much weaker tissue damage to colorectal tissue than CPT-11, and its impacts on food intake and body weight loss were more transient and recovered faster than CPT-11 in mice. This could be partially explained by the pharmacokinetic findings, which showed that PCC0208037 and its active metabolite, SN-38, were more accumulated in tumor tissue than in the intestine, as compared to CPT-11. Taken together, these results described a novel Topo I inhibitor with a comparative advantage over the standard treatment of colorectal cancer CPT-11 and could be a promising candidate compound for the treatment of colorectal cancer that warrants further investigation.