Evodiamine-inspired dual inhibitors of histone deacetylase 1 (HDAC1) and topoisomerase 2 (TOP2) with potent antitumor activity

A great challenge in multi-targeting drug discovery is to identify drug-like lead compounds with therapeutic advantages over single target inhibitors and drug combinations. Inspired by our previous efforts in designing antitumor evodiamine derivatives, herein selective histone deacetylase 1 (HDAC1) and topoisomerase 2 (TOP2) dual inhibitors were successfully identified, which showed potent in vitro and in vivo antitumor potency. Particularly, compound 30a was orally active and possessed excellent in vivo antitumor activity in the HCT116 xenograft model (TGI = 75.2%, 150 mg/kg, p.o.) without significant toxicity, which was more potent than HDAC inhibitor vorinostat, TOP inhibitor evodiamine and their combination. Taken together, this study highlights the therapeutic advantages of evodiamine-based HDAC1/TOP2 dual inhibitors and provides valuable leads for the development of novel multi-targeting antitumor agents.     

膀胱癌组织P-gp,GST-π和TOPO-Ⅱ表达评估灌注化疗

目的：探讨膀胱癌的多药耐药性(MDR)，指导灌注化疗用药。方法：采用免疫组化法检测44例膀胱癌病理标本中P-糖蛋白(P-gp)、谷胱肽S转移酶(GST-π)和拓扑异构酶(TOPO—Ⅱ)的表达，评估肿瘤耐药谱。结果：①P-gp检测显示，54．5％的病例对阿毒索、丝裂毒索、长春新碱等抗生索类和生物碱类抗癌药高耐药。②GST-π检测显示仅34．1％的病例对顺铂、环磷酰胺等高耐药，而反有56．8％的病例对该类药无耐药或低度耐药。③TOPO-Ⅱ检测显示对阿霉索、柔红毒索、VP16等TOPO-Ⅱ抑制剂类抗癌药，仅13．6％的病例高度耐药，29．5％中度耐药。56．8％低度耐药。结论：检测膀胱癌MDR，了解多药耐药谱，可指导灌注化疗用药。     

Arsenic trioxide exposure to ovarian carcinoma cells leads to decreased level of topoisomerase II and cytotoxicity

The objective of this study was to investigate the effect of arsenic trioxide (As(2)O(3)) on topoisomerase II levels using western blotting method on MDAH 2774 ovarian carcinoma cell culture. Experimental designs were established to determine the cytotoxic effects of As(2)O(3) on MDAH 2774 cells and the IC50 (fatal dose for the 50% of cells) value. Cytotoxicity experiments were carried out using various concentrations of As(2)O(3). The 2,3-bis[2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) and trypan blue dye-exclusion tests were used to evaluate cytotoxicity. Topoisomerase II expressions were investigated using western blotting method with various concentrations of As(2)O(3). Densitometric analysis of topoisomerase 2 bands was carried out using Quantity One 1-D analysis software (Bio-Rad USA, Life Science Research, Hercules, CA). IC50 value of As(2)O(3) was found to be 5 x 10(-6) M for MDAH 2774 cells. When the bands were evaluated, it was observed that there was a decrease in topoisomerase II levels in MDAH 2774 cells with increasing concentrations of As(2)O(3). It was also observed by the densitometric analysis that topoisomerase II expression ratios of MDAH 2774 cells were decreased by approximately 50% at this concentration. Topoisomerase II levels were significantly decreased with the increasing concentrations of As(2)O(3). Inhibition of topoisomerase II enzyme was one of the antiproliferative influence mechanisms of As(2)O(3).     

拓扑替康在卵巢癌治疗中的新进展

拓扑替康是一种新的半合成喜树碱衍生物 ,通过抑制拓扑异构酶Ⅰ而产生抗肿瘤作用。大量研究表明拓扑替康对卵巢癌尤其是经铂类药物化疗失败 ,复发的卵巢癌患者有较好疗效。本文就拓扑替康在卵巢癌临床应用中的新进展进行综述。     

The potential of topoisomerase I inhibitors in the treatment of CNS malignancies: report of a synergistic effect between topotecan and radiation

Summary Despite innovations in imaging, surgery, and radiation therapy, local failure remains the principle clinical problem in most CNS malignancies. To date, chemotherapy has not made a major impact in the treatment of most adult CNS tumors. The inroads made by chemotherapy in pediatric CNS malignancies suggest that novel drugs, or drug combinations, may improve therapy. Topoisomerase I (Topo I) inhibitors are a relatively new group of chemotherapy drugs with a novel mechanism of action. Drugs in this group currently undergoing clinical trials are the Camptothecin analogues Topotecan, CPT-11, and 9-aminocamptothecin. There is substantial preclinical and some clinical evidence to suggest that these drugs could be useful in the treatment of CNS malignancies. Preclinical studies with the water soluble Topo I inhibitor, Topotecan, demonstrate antineoplastic activity in a variety of CNS malignancies. In addition, Topotecan has good CNS penetration in primates, and recent preliminary phase I and II clinical trials of Topotecan in pediatric and adult CNS malignancies have been promising. In this paper, we describe the unique mechanism of action, antineoplastic activity, and radiosensitizing properties of Topo I inhibitors. We present the first report demonstrating potentiation of radiation lethality by Topotecan in a human glioma (1354) cell line. The dose enhancement ratio was 3.2 at 10% survival. Thus, there is evidence to suggest that Topo I inhibitors may be beneficial in the treatment of CNS neoplasms on the basis of their antineoplastic activity alone, as well as their radiosensitizing effects. Two clinical trials which utilize concurrent Topotecan and radiation in the treatment of pediatric and adult CNS malignancies are discussed.     

Prognostic Significance of p27, Ki-67, and Topoisomerase lla Expression in Clinically Nonfunctioning Pancreatic Endocrine Tumors

Nonfunctioning islet cell tumors or pancreatic endocrine tumors are the most common type of malignant islet cell tumor. Although previously detected usually at an advanced stage because of mass effect, the early detection rate of small localized disease has been increasing. To date it has been difficult to predict the clinical behavior in localized regional nonfunctioning tumors. To investigate potential markers predicting malignancy and poor prognosis in nonfunctioning pancreatic endocrine tumors, we analyzed the expression of Ki-67, topoisomerase IIα (Topollα), and p27, as well as a variety of clinicopathologic parameters in 76 cases of nonfunctioning islet cell tumors (23 benign cases and 53 malignant cases). Ki-67, Topollα, and p27 labeling indices were significantly different between benign and malignant tumors. Expression of Ki-67, Topollα, and p27 were associated with survival in patients with a malignant tumor in a univariate setting. However, only p27 and Topollα were jointly associated with survival in multivariate analysis. Immunohistochemical staining for p27, Topollα, and Ki-67 can be helpful in the diagnosis of nonfunctioning pancreatic endocrine tumor. Analysis of p27 and Topollα may also have potential utility as prognostic factors for malignant tumors.     

New opportunities in chemosensitization and radiosensitization: modulating the DNA-damage response

Many current cancer treatments, including certain classes of chemotherapeutics and radiation, induce cytotoxicity by damaging DNA. However, many cancers are resistant to these therapies, which represents a significant challenge in the clinic. Thus, modulating DNA-damage responses to selectively enhance the sensitivity of cancer cells to these therapies is highly desirable. When DNA damage is detected, DNA checkpoint mechanisms are activated to halt cells at various phases of the cell cycle. Simultaneously, DNA-damage sensors transduce signals to activate DNA-repair mechanisms via de novo expression or post-translational modification of enzymes required for DNA repair. p53 is the major player in a checkpoint that arrests cells at the G₁/S boundary, while checkpoint kinase (Chk)1 is critical for the G₂/M checkpoint and also the S checkpoint that prevents cell cycle progression after replication defects (intra-S-phase checkpoint) or S/M uncoupling (S/M checkpoint). Poly(ADP-ribose) polymerase is involved in sensing DNA single-strand breaks and inducing DNA repair via poly(ADP-ribosyl)ating various DNA-binding and DNA-repair proteins. In this review, strategies for implementing small-molecule inhibitors of poly(ADP-ribose) polymerase and Chk1, which are emerging as potential adjuncts to current therapies, are discussed.     

The role of pixantrone in the treatment of non-Hodgkin’s lymphoma

Pixantrone is an anthraquinone-based inhibitor of topoisomerase II. It is similar to both the anthracycline doxorubicin and the anthracenedione mitoxantrone, but lacks the 5,8-dihydroxy substitution pattern of mitoxantrone, and has a tricyclic system unlike the tetracyclic structure seen with anthracyclines. Anthracyclines are the most active drugs in lymphoma therapy, but their use is limited by their cumulative and irreversible cardiotoxicity. Pixantrone was developed to improve the toxicity profile of the current anthracyclines and anthracenediones while maintaining their activity. Interestingly, pixantrone showed no measurable cardiotoxicity compared with its parent compound mitoxantrone or other anthracyclines at equi-effective doses in several animal models. Together with its superior cytotoxic activity in leukaemia and lymphoma models, these features render the drug a promising candidate for clinical development in indolent and aggressive non-Hodgkin’s lymphoma. In this review, the latest results of the use of pixantrone in indolen-t and aggressive non-Hodgkin’s lymphomas are summarised.