Effective Chemotherapeutic Agent For Treatment Research Articles

Design, synthesis and pharmacological screening of novel renoprotective methionine-based peptidomimetics: Amelioration of cisplatin-induced nephrotoxicity

Cisplatin (CP) is an effective chemotherapeutic agent for treatment of various types of cancer, however efforts are needed to reduce its toxic side effect. Previous studies revealed promising effect of peptides in decreasing CP induced nephrotoxicity. Herein, novel Met-based peptidomimetics were synthesized using N-acylbenzotriazole as acylating agent in high yield. Evaluation of renoprotective effect of the synthesized targets on CP treated kidney cell line (LLC-PK1) revealed that pretreatment with 1/3 IC50 of targets II, IIIa-g attenuated CP induced cell death where the IC50 of CP was raised from 3.28 µM to 9.25-41.1 µM. The most potent compounds IIIg, II and IIIb exhibited antioxidative stress in CP-treated LLC-PK1 cells as confirmed by raising GSH/GSSG ratio and SOD concentration as well as decreasing ROS and MDA. Additionally, in vivo experiments using Sprague Dawley rats showed renoprotective effect of IIIg against CP-induced nephrotoxicity as evidenced by improved results of renal function tests and attenuated CP-induced renal structural injury. Moreover, antioxidant activity of IIIg was demonstrated via its ability to reduce renal MDA level and up-regulate renal antioxidant element GSH level. Further, immunohistochemistry of renal specimens showed the ability of IIIg to restore CP-induced suppression of Nrf2. Interestingly, in vivo and in vitro studies demonstrated that IIIg had no effect on CP antiproliferative activity. An assessment of the ADMET properties revealed that targets IIIg, II and IIIb showed good drug-likeness in terms of their physicochemical, pharmacokinetic properties. The findings presented here showcase that IIIg is a promising renoprotective candidate with antioxidative stress potential.

Identification of plumbagin as an effective chemotherapeutic agent for treatment of Gyrodactylus infections

Monogenean parasites are responsible for severe economic losses of both freshwater and marine aquaculture industries. Current chemotherapeutic treatments are consuming, expensive, and harmful to water quality and human health. Medicinal plants are a reliable source of alternative anthelmintic agents. In the pursuit of novel anti-monogenean drugs, in vivo anthelminthic efficacy of 26 selected phytochemical compounds was studied, by choosing Gyrodactylus kobayashi infecting goldfish (Carassius auratus) as a model. The screening results showed that four compounds (plumbagin (PLB), thymoquinone, osthole and psoralen) had the highest activity against G. kobayashii with EC99 value ranging from 0.4 to 4.0 mg/L after 48-h exposure. Among these active compounds, PLB was the most efficacious one and selected for the next study. In vitro trials revealed the clear anti-parasitic effects of PLB, with complete death at 45 min of exposure at a concentration of 2.0 mg/L, withdrawal of PLB afterward did not lead to the recovery of the exposed parasites. Bathing G. kobayashii infected goldfish in PLB also significantly reduced the worm burden, with an extremely low EC50 value of 0.09 mg/L after 48-h immersion. The results also showed that one short bath using very low concentrations of 0.4–0.7 mg/L for 30–60 min was effective in eliminating G. kobayashii infection with no visible fish toxicity. Acute toxicity assay indicated the 48-h LC50 of PLB against goldfish was 0.657 mg/L. Furthermore, SEM analysis displayed that PLB-mediated worm killing was associated with the tegumental damages. As seen by TEM, in vivo treatment against G. kobayashii with PLB also caused vacuolization and lysis of parasite's tegument, besides, differing degrees of damage to vitelline cells were observed in treated worms. Collectively, simple chemical structure along with the potent efficacy demonstrated that PLB could serve as an ideal leading compound in the development of a commercial drug to control Gyrodactylus infections in aquaculture

Effect of Spironolactone on Doxorubicin Induced Cardiomyopathy in Adult Male Albino Rat: Histological, Pharmacological and Biochemical Study

Abstract Background: Doxorubicin, an anthracycline drug, is an effective chemotherapeutic agent for treatment of solid tumors and hematological malignancies. However, its clinical use is limited by cardiotoxicity, such as irreversible degenerative cardiomyopathy, electrocardiographic changes, and congestive heart failure. The studies have been proved that spironolactone can ameleorate cardiac fibrosis. This drug is already indicated in treatment of doxorubicin-induced cardiotoxicity to prevent further deterioration. Aim of Study: Is to elucidate protective and therapeutic effect of spironolactone on doxorubicin induced cardiomy-opathy. Material and Methods: Fifty adult male albino rats weigh-ing 180-220g were used in this study. The rats were divided into five groups 10 rats each: Group I (Normal control): Rats received single injection of saline solution 0.9% intraperito-neally once daily for 14 days. Group II (Doxorubicin admin-straion group): Rats were injected once with doxorubicin intaperitoneally at a dose of 10mg/kg once daily for 14 days. Group III (Doxorubicin and spironolactone pre-administration group): Rats were injected once with doxorubicin intaperito-neally at a dose of 10mg/kg once daily for 14 days and pretreated with spironolactone for seven days before doxoru-bicin administration Group IV (Doxorubicin and spironolactone co-administration group): Rats were injected once with dox-orubicin intaperitoneally at a dose of 10mg/kg once daily and co-treated with spironolactone for 14 days Group V (Doxoru-bicin and spironolactone Post-administration group): Rats were injected once with doxorubicin intaperitoneally at a dose of 10mg/kg once daily for 14 days and followed by spironol-actone for 7 days. The dose of spironolactone was 40mg/kg given by oral gavage. Results: Doxorubicin injection exerted various histological and laboratory alterations such as myocardial fibrosis, bal-looned mitochondria and elevated cardiac enzymes. Spironolactone could improve all histological and functional deterio-ration exerted by doxorubicin injection especially when given before doxorubicin administration. Conclusion: It could be concluded that Spironolactone could prevent the adverse histological and functional alterations induced by intraperitoneal injection of doxorubicin in the myocardium of adult male albino rat.

Remote Ischemic Preconditioning Protects Cisplatin-Induced Acute Kidney Injury through the PTEN/AKT Signaling Pathway.

Although cisplatin (Cis) is an effective chemotherapeutic agent in treatment of various cancers, its adverse effect of nephrotoxicity limits the clinical application. Remote ischemic preconditioning (RIPC) is a strategy to induce resistance in a target organ against the oxidative stress and injury by applying transient, brief episodes of ischemia. However, whether RIPC exerts protective effect on Cis-induced renal injury remains unclear. In this study, we showed that RIPC significantly alleviated the renal functional and histopathological damage of Cis-induced acute kidney injury (AKI) mice. Furthermore, RIPC substantially reversed the downregulation of miR-144 and upregulation of PTEN in renal tissues of Cis-induced AKI mice and alleviated tubular cell apoptosis via activating PTEN/AKT signaling. In mechanism, we demonstrated that miR-144 directly targets the 3′-UTR of PTEN mRNA, and then the elevation of miR-144 in RIPC activates PTEN/AKT signaling by downregulating PTEN expression to achieve its antiapoptosis effect. Collectively, our results indicate that RIPC may be a potential therapeutic strategy in Cis-induced AKI, and provide insights on the underlying molecular mechanisms of cisplatin's nephrotoxicity.

Biodegradable reduction-responsive polymeric micelles for enhanced delivery of melphalan to retinoblastoma cells

Melphalan (MEL) is an effective chemotherapeutic agent for treatment of retinoblastoma (Rb) which is the most common childhood malignancy. However, the inherent cardiopulmonary toxicity and hazardous integration limit its therapeutic effect on RB. N-Acetylheparosan (AH), a natural heparin-like polysaccharide in mammals with long circulation effect and good biocompatibility, was linked by d-α-tocopherol acid succinate (VES) via and cystamine (CYS) to synthesize reduction-responsive N-acetylheparosan-CYS-Vitamin E succinate (AHV) copolymers. In addition, CYS was replaced by adipic acid dihydrazide (ADH) to obtain a control of non-reduction-responsive polymers N-acetylheparosan-ADH-Vitamin E succinate (ADV). MEL-loaded AHV micelles (MEL/AHV) as well as ADV micelles (MEL/ADV) were prepared with small particle size and high drug loading content. In vitro drug release showed that MEL/AHV micelles presented obvious reduction-triggered release behavior compared with MEL/ADV. In vitro antitumor effects were investigated using WERI-Rb-1 retinoblastoma cells. Cytotoxicity experiments showed that the IC50 of MEL/AHV was significantly lower than that of free MEL and MEL/ADV, suggesting that MEL/AHV enhanced the cytotoxicity against retinoblastoma cells. Furthermore, MEL/AHV micelles were more easily uptaken by multiple pathways compared with MEL/ADV and free MEL. Therefore, MEL/AHV might be a potential delivery system for enhanced delivery of melphalan to Rb cells.

Cathepsin L silencing increases As2O3 toxicity in malignantly transformed pilocytic astrocytoma MPA58 cells by activating caspases 3/7

Low-grade, pilocytic astrocytomas are treated by resection, but additional therapy is necessary for those tumors with anaplastic features. Arsenic trioxide (As2O3) is emerging as an effective chemotherapeutic agent for treatment of malignant glioblastoma multiforme, where Cathepsin L silencing enables lower, less harmful As2O3 concentrations to achieve the desired cytotoxic effect. Here, we evaluated the effects of As2O3 combined with stable Cathepsin L shRNA silencing on cell viability/metabolic activity, and apoptosis in primary cultures of recurrent malignantly transformed pilocytic astrocytoma (MPA). These cells expressed high Cathepsin L levels, and when grown as monolayers and spheroids, they were more resistant to As2O3 than the U87MG glioblastoma cell line. Caspases 3/7 activity in MPA58 spheroids was not significantly affected by As2O3, possibly due to higher chemoresistance of primary biopsy tissue of less malignant astrocytoma versus the malignant U87MG cell line. However, As2O3 treatment was cytotoxic to MPA spheroids after silencing of Cathepsin L expression. While Cathepsin L silencing only slightly decreased the live/dead cell ratio in As2O3-treated MPA-si spheroids under our experimental conditions, there was an increase in As2O3-mediated apoptosis in MPA-si spheroids, as indicated by elevated caspases 3/7 activity. Therefore, Cathepsin L silencing by gene manipulation can be applied when a more aggressive approach is needed in treatment of pilocytic astrocytomas with anaplastic features.

Hesa-A Down-Regulates erb/b2 Oncogene Expression and Improves Outcome of Oral Carcinoma in a Rat Model.

Oral carcinoma (OC) remains one of the most difficult malignancies to cure. Hesa-A is an Iranian herbal-marine compound that has shown promising anti-tumor properties against various human tumors. However, its mechanism of action remains to be addressed. The present study was conducted to evaluate the effect of two doses of Hesa-A on mRNA expression of erb\b2 as a main prognosticator tumor marker for OC in an animal model. A total of 60 rats were randomly divided into 5 groups of 12 animals each. Rats in carcinoma groups received 0, 250 and 500 mg/kg body weight doses of Hesa-A 3 times a day. The other two groups were considered as treated and untreated control groups. At the end of the experiment, animals were sacrificed and tongue tissues subjected to H and E staining and real time PCR. Our results showed that compared to the control group, erb\ b2 was over-expressed ~ 30% in the carcinoma group. After treatment with 250 mg/kg and 500 mg/kg body weight of Hesa-A , erb\b2 levels dropped by 24.1% and 3.4 % respectively compared to the control carcinoma group (p<0.01, p<0.0001). Moreover, there was a significant relation between erb\ b2 mRNA content and observed pathological changes in studied groups (p<0.05). These data provide insight into mechanism(s) by which Hesa-A may improve clinical outcome of oral carcinoma by affecting oncogene erb\b2 expression and suggest Hesa-A as an effective chemotherapeutic agent in treatment of HER+ tumors.

Survey of clinical features, pathogenesis and therapeutic options for Ebola haemorrhagic fever

The genus Ebola virus first was recognized in 1976, when two outbreaks occurred in Zaire and Sudan. Ebola virus disease (EVD) is a highly contagious disease that can affect both human and nonhuman primates: Zaire ebolavirus (ZEBOV), Sudan ebolavirus (SEBOV), Cote d’Ivoire ebolavirus (CEBOV), Bundibugyo ebolavirus (BEBOV) and Reston ebolavirus (REBOV) are five members of the Filoviridae family that can cause haemorrhagic fever. EVD is transmitted by direct contact with contaminated blood or other biological fluids of the infected animals such as chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the rainforest. Ebola is responsible for different clinical futures that can be ranged from fever, headache, arthralgia, myalgia, abdominal pain, anorexia and vomiting to severe respiratory disorders, viral hemorrhagic fever, cardio-vascular disorders and hypovolaemic shock. Although there is no specific treatment for EVD, considerable advances like use of monoclonal antibody, intefron and Favipiravir/T-705 as effective chemotherapeutic agent in treatment of EBV have been made. To date, 25 outbreaks of EVD have been reported. Hence, EVD as a zoonotic disease should be more focused not only in endemic area but also in throughout the world. Awareness of the disease and routes of transmission and also continuous surveillance to combat disease and outbreaks is necessary.

Identification of plumbagin and sanguinarine as effective chemotherapeutic agents for treatment of schistosomiasis

Schistosomiasis, a snail-borne parasitic disease, affects more than 200 million people worldwide. Currently the treatment of schistosomiasis relies on a single therapy of praziquantel, a drug developed over 30years ago. Thus, there is an urgent need to develop alternative antischistosomal drugs. In the pursuit of novel antischistosomal drugs, we examined the antischistosomal activities of 45 compounds that had been reported to exhibit antimicrobial and/or antiparasitic activities. Two plant-derived compounds, plumbagin and sanguinarine, were found to possess potent antischistosomal activities in vitro. For both the compounds, a concentration of 10μM (equivalent to 1.88μg/ml for plumbagin and 3.68μg/ml for sanguinarine) resulted in 100% mortality at 48h, which meets the World Health Organization’s (WHO) criterion of “hit” compounds for the control of schistosomiasis. Morphological changes and tegumental alterations of the dead worms treated by the two compounds were quite different. The significant morphological changes of worms after treatment by the two compounds suggest the two compounds target different biological pathways, both of which result in parasite’s death. This study provides evidence to suggest plumbagin and sanguinarine have real potential as effective alternative chemotherapeutic agents for the treatment of schistosomiasis.

Camptothecin Induces Apoptosis in Cancer Cells via MicroRNA-125b-Mediated Mitochondrial Pathways

Camptothecin (CPT) is an effective chemotherapeutic agent for treatment of patients with cancer. The mechanisms underlying CPT-mediated responses in cancer cells are not fully understood. MicroRNA (miRNA) play important roles in tumorigenesis and drug sensitivity. However, the interaction between camptothecin and miRNA has not been previously explored. In this study, we verified that miR-125b was down-regulated in CPT-induced apoptosis in cancer cells and that ectopic expression of miR-125b partially restored cell viability and inhibited cell apoptosis that was induced by CPT. In addition, we demonstrated that CPT induced apoptosis in cancer cells by miR-125b-mediated mitochondrial pathways via targeting to the 3'-untranslated (UTR) regions of Bak1, Mcl1, and p53. A significant increase in Bak1, Mcl1, and p53 protein levels was detected in response to the treatments of CPT. It is noteworthy that the expression levels of Bak1, Mcl1, and p53 increased in a time-dependent manner and negatively correlated with miR-125b expression. It is noteworthy that we revealed that miR-125b directly targeted the 3'UTR regions of multiple genes in a CPT-induced mitochondrial pathway. In addition, most targets of miR-125b were proapoptotic genes, whereas some of the targets were antiapoptotic genes. We hypothesized that miR-125b may mediate the activity of chemotherapeutic agents to induce apoptosis by regulating multiple targets. This is the first report to show that camptothecin induces cancer cell apoptosis via miRNA-mediated mitochondrial pathways. The results suggest that suppression of miR-125b may be a novel approach for the treatment of cancer.

Lipid raft-dependent death receptor 5 (DR5) expression and activation are critical for ursodeoxycholic acid-induced apoptosis in gastric cancer cells

Ursodeoxycholic acid (UDCA) is known as a suppressor of cholestatic liver diseases and colorectal cancer development. Here, we demonstrate that UDCA induces apoptosis without necrotic features in SNU601, SNU638, SNU1 and SNU216 human gastric cancer cells, implying its possible use as an effective chemotherapeutic agent in treatment of gastric cancer. UDCA-induced apoptosis was dominantly mediated by an extrinsic pathway dependent on caspase-8, -6 and -3. UDCA increased expression of death receptor 5 [(DR5), also known as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 2], and this DR appeared to be responsible for UDCA-induced apoptosis, as evidenced by DR5 knockdown. UDCA triggered formation of lipid rafts that played crucial roles in UDCA-induced apoptotic actions. Lipid rafts were required not only for provision of a proper site for DR5 action but also for mediation of DR5 expression. In addition, reactive oxygen species (ROS) and protein kinase C (PKC) δ appeared to be implicated in UDCA-induced raft-dependent DR5 expression. Our results indicate that UDCA-induced apoptosis is mediated by DR5 expression, which is regulated by the raft formation/ROS production/PKCδ activation pathway and DR5 localization into lipid rafts in gastric cancer cells. Tumor-suppressive activity of UDCA was confirmed in an in vivo system: UDCA (120 mg/kg/day) significantly decreased tumor growth in gastric cancer xenograft mice. Taken together, our results demonstrate that UDCA can be used as a potent chemotherapeutic agent for treatment of gastric cancer.

MicroRNA-125b Confers the Resistance of Breast Cancer Cells to Paclitaxel through Suppression of Pro-apoptotic Bcl-2 Antagonist Killer 1 (Bak1) Expression

Paclitaxel (Taxol) is an effective chemotherapeutic agent for treatment of cancer patients. Despite impressive initial clinical responses, the majority of patients eventually develop some degree of resistance to Taxol-based therapy. The mechanisms underlying cancer cells resistance to Taxol are not fully understood. MicroRNA (miRNA) has emerged to play important roles in tumorigenesis and drug resistance. However, the interaction between the development of Taxol resistance and miRNA has not been previously explored. In this study we utilized a miRNA array to compare the differentially expressed miRNAs in Taxol-resistant and their Taxol-sensitive parental cells. We verified that miR-125b, miR-221, miR-222, and miR-923 were up-regulated in Taxol-resistant cancer cells by real-time PCR. We further investigated the role and mechanisms of miR-125b in Taxol resistance. We found that miR-125b was up-regulated in Taxol-resistant cells, causing a marked inhibition of Taxol-induced cytotoxicity and apoptosis and a subsequent increase in the resistance to Taxol in cancer cells. Moreover, we demonstrated that the pro-apoptotic Bcl-2 antagonist killer 1 (Bak1) is a direct target of miR-125b. Down-regulation of Bak1 suppressed Taxol-induced apoptosis and led to an increased resistance to Taxol. Restoring Bak1 expression by either miR-125b inhibitor or re-expression of Bak1 in miR-125b-overexpressing cells recovered Taxol sensitivity, overcoming miR-125-mediated Taxol resistance. Taken together, our data strongly support a central role for miR-125b in conferring Taxol resistance through the suppression of Bak1 expression. This finding has important implications in the development of targeted therapeutics for overcoming Taxol resistance in a number of different tumor histologies.

Abstract 2109: Mir-125b confers the resistance of cancer cells to Taxol through suppression of Bak1

Abstract Paclitaxel (Taxol) is one of the most effective chemotherapeutic agents for treatment of cancer patients. Despite impressive initial clinical responses, the majority of patients will eventually develop some degree of resistance to Taxol-based therapy. The mechanisms underlying cancer cells resistance to Taxol are not fully understood. microRNA (miRNA) has emerged to play important roles in tumorigenesis and drug-resistance. However, the interaction between the development of Taxol resistance and miRNA has not been previously explored. In this study, we utilized a miRNA array to screen differentially expressed miRNAs, comparing Taxol-resistant and their Taxol-sensitive parental cells, and investigated the role and mechanisms of miR-125b in Taxol resistance of breast cancer cells. We found that miR-125b was up-regulated in Taxol-resistant cells, with its overexpression causing a marked inhibition of Taxol-induced cytotoxicity and apoptosis, and a subsequent increase in the resistance of cancer cells to Taxol. Moreover, we demonstrated that Bak1 is a direct target of miR-125b in breast cancer cells, and down- regulation of Bak1 suppressed Taxol- induced apoptosis and led to an increased resistance to Taxol. Furthermore, restoring the expression of Bak1 by either miR-125b inhibitor or specific siRNA recovered Taxol sensitivity, overcoming miR-125-mediated Taxol resistance. Taken together, our data strongly supports a central role for miR-125b in conferring Taxol resistance through the suppression of Bak1 expression. This finding has important implications in the development of targeted therapeutics for overcoming Taxol resistance in a number of different tumor histologies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2109.

Tamoxifen-induced activation of p21Waf1/Cip1 gene transcription is mediated by Early Growth Response-1 protein through the JNK and p38 MAP kinase/Elk-1 cascades in MDA-MB-361 breast carcinoma cells

Tamoxifen (TAM) is a synthetic non-steroidal anti-estrogen compound that is widely used as an effective chemotherapeutic agent for treatment and prevention of breast cancer. Unfortunately, prolonged treatment with TAM causes TAM-responsive tumors to become TAM resistant through an as-yet-unknown mechanism. To develop novel anti-breast cancer agents that are therapeutically superior to TAM, we must first fully understand the biological effects of TAM. In this study, we found that TAM treatment of MDA-MB-361 breast cancer cells activated p21Waf1/Cip1 gene transcription independently of p53. Furthermore, TAM-induced p21Waf1/Cip1 promoter activity was enhanced by transient expression of the gene encoding Early Growth Response-1 (Egr-1) protein, a transcription factor that plays an important role in cell growth and differentiation. The TAM-induced p21Waf1/Cip1 promoter activity was blocked by the expression of small interfering RNA (siRNA) targeted to Egr-1 mRNA. In addition, induction of Egr-1 expression by TAM occurred at the transcriptional level via Ets-domain transcription factor Elk-1 through the JNK and p38 mitogen-activated protein (MAP) kinase pathways. Inhibition of the JNK and p38 MAP kinase signals inhibited Egr-1-mediated p21Waf1/Cip1 promoter activity. We conclude that TAM stimulation of p21Waf1/Cip1 gene transcription in MDA-MB-361 cells depends largely on Elk-1-mediated Egr-1 expression induced by activation of the JNK and p38 MAP kinase pathways.

Thymidylate synthetase mRNA levels are increased in liver metastases of colorectal cancer patients resistant to fluoropyrimidine-based chemotherapy.

BackgroundFluoropyrimidines such as 5-fluorouracil (5-FU) and 5-fluoro-2'deoxyuridine (FUDR) are among the most effective chemotherapeutic agents for treatment of metastatic colorectal cancer (CRC). Increased expression of thymidylate synthetase (TS) in CRC metastases has been proposed to be an important mechanism of resistance to fluoropyrimidine-based chemotherapy.MethodsThe present study investigated whether TS mRNA levels in liver metastases of 20 CRC patients before treatment with FUDR by hepatic arterial infusion (HAI) correlated with frequency of clinical response or survival duration.ResultsMedian survival duration of patients with TS mRNA levels above and below the median was 15 and 18 months, respectively (p > 0.05). Clinical response was achieved in 40% of patients with low TS mRNA levels, but in only 20% of patients with high TS mRNA levels (p = 0.01). TS mRNA levels were also measured for liver metastases of 7 of the patients that did not achieve a clinical response. A statistically significant increase in expression of TS mRNA was observed for liver metastases resistant to chemotherapy (21 ± 14) in comparison to liver metastases of the same patients before chemotherapy (8 ± 4) (p = 0.03).ConclusionThis is the first report to demonstrate increased TS expression in liver metastases from CRC patients resistant to fluoropyrimidine based chemotherapy. These findings are consistent with previous studies indicating that increased TS expression is associated with resistance to fluoropyrimidine-based chemotherapy.

In vitro inhibition of estrogen sulfoconjugation by some 2- and 4-substituted estra-1,3,5(10)-trien-17.beta.-ols

Hormone-responsive rat and human mammary tumor, unlike normal epithelium, actively sulfoconjugates estrogens. The title compounds (9-11) were synthesized in search of specific inhibitors of estrogen sulfotransferase as a possible means of developing effective chemotherapeutic agents for treatment of hormone-dependent human mammary cancer. 4-Nitroestrone 3-triflate (7a) was converted to the corresponding estradiol derivative (8a) in 93% yield by reduction with NaBH4 under phase-transfer conditions. Catalytic reduction (10% Pd/C) of the latter gave 4-aminoestra-1,3,5(10)-trien-17 beta-ol (9a) in 77% yield. These same reactions were applied consecutively to 4-nitroestrone 3-nonaflate (7b) to give 9a in 56% overall yield. The amino steroid (9a) was converted to 4-fluoroestra-1,3,5(10)-trien-17 beta-ol (10a) via a Balz-Schiemann reaction, in 17% overall yield. Successive NaBH4 and (10% Pd/C) catalytic reductions of 4-fluoroestrone 3-O-(1-phenyl-1H-tetrazol-5-yl) ether (2b) provided a less satisfactory route to 10a. MCPBA oxidation of 9a gave 4-nitroestra-1,3,5(10)-trien-17 beta-ol (11a) in 56% yield. The same series of reactions were applied to 2-nitroestrone 3-triflate (7c) to give 2-amino- (9b), 2-fluoro- (10b), and 2-nitro- (11b) estra-1,3,5(10)-trien-17-ols in comparable yields. Substitution in the A ring results in improved inhibition of porcine endometrial sulfotransferase sulfoconjugation of estradiol relative to estra-1,3,5(10)-trien-17 beta-ol (4a). Moreover, electronegative substitution at C-4 of 4a is more effective than at C-2. In particular, the Ki (2.43 +/- 0.16 microM) of 11a is sixfold smaller than that of the unsubstituted steroid (4a).

Characteristics of prognosis and response to an imidazole carboxamide in malignant melanoma.

In a prospective randomized study of 155 patients, dimethyltriazeno imidazole carboxamide, 2.0 or 4.5 mg. per kilogram given for 10 successive daily intravenous doses, resulted in ob;ective response in 28 per cent of 115 evaluable patients. The 2.0 mg. schedule produced a significantly greater rate and duration of response (p ≤ 0.05) than did the 4.5 mg. schedule. In half of the responding patients the response exceeded 6 months in duration. Urinary melanogens, detected by a qualitative test in 29 per cent of patients tested, suggested widespread disease but were not helpful in diagnosing clinically occult recurrent disease. Toxicity was somewhat greater on the 4.5 mg. regimen, but in general it was mild; there were no drug deaths. The drug, which has some interesting and unusual dose‐toxicity‐response relationships, appears to be the most effective chemotherapeutic agent for treatment of malignant melanoma.

Further experience in the treatment of rocky mountain spotted fever with chloramphenicol

The data on sixteen patients with Rocky Mountain spotted fever treated with chloramphenicol are presented. Findings in these patients confirm previous results that the antibiotic is an effective chemotherapeutic agent for treatment of this rickettsiosis.