SARS-CoV-2 PCR positivity rate and seroprevalence of related antibodies among a sample of patients in Cairo: Pre-wave 2 results of a screening program in a university hospital.

BACKGROUND: Research has revealed that asymptomatic and pre-symptomatic infections are important contributors to the transmission of SARS-CoV-2 in populations. In Egypt, the true prevalence of infections is veiled due to the low number of screening tests. The aim of this study was to determine the SARS-CoV-2 PCR positivity rate as well the seroprevalence of the SARS-CoV-2 antibodies before the ultimate development of a second wave of the epidemic in Cairo, Egypt. METHODS: Our study was carried out between May 5 and the end of October 2020. It included all patients requiring admission to Ain Shams University hospitals. An interview questionnaire was used to collect demographic and clinical data. Laboratory tests for all participants included RT-PCR and total antibody assay for SARS-CoV-2. RESULTS: A total of 4,313 subjects were enrolled in our study, with females representing 56% of the sample. Adults and middle-aged individuals represented around 60% of the study sample. The positivity rate of SARS-CoV-2 PCR was 3.84% (95% CI 3.29-4.48), and the SARS-CoV-2 antibody seroprevalence was 29.82% (95% CI: 28.16-31.51). Males showed a higher risk for getting the COVID-19 infection, while middle-age group had significantly higher antibody seroprevalence rates. CONCLUSION: SARS-CoV-2 infection imposes a high burden on the community as detected by high seroprevalence rates.

Investigation of a COVID-19 outbreak in a University Cardio-Thoracic Hospital in Cairo: exploration of the risk to healthcare workers and patients.

Background: Corona virus Disease 2019 (COVID-19) pandemic has posed a challenge to health sectors all over the world. The pandemic arrived in Egypt a few weeks after Europe and Asia, with rapidly rising numbers. Health care workers (HCWs) are front liners sustaining a major risk of acquiring the infection. Aim: In this work, we analyse an outbreak of COVID-19 in a University hospital in Cairo involving HCWs of different categories, patients and patients' accompanying relatives. Methods: Following the reporting of the first COVID-19 confirmed case; a 55-year-old nurse at the hospital, a total of 645 healthcare workers, patients and patients' accompanying relatives were tested for SARS-CoV-2 by real-time reverse transcription polymerase chain reaction (rRT-PCR) assay. Results: Twenty-four out of 589 HCWs, 3 out of 42 patient and 4 out of 14 patients' accompanying relatives tested positive for COVID-19. No physicians, pharmacists or technicians were infected. Nursing staff and housekeeping staff were the most at risk of contracting the infection with a risk ratio of 4.99 (95% CI: 1.4-17.6) and 5.08 (95% CI: 1.4-18.4) respectively. Clustering of infected HCWs was observed in paediatrics' ICU and in the 6th floor of the hospital. Conclusions: Nursing and housekeeping staff sustain a significantly higher risk of COVID-19 infection compared to other staff categories. The nature of their duties and the frequent unprotected contact between members of these categories may play a role in increasing their risk.

Dose Issues in Cancer Chemotherapy.

In this review, human methotrexate dosing regimens, as well as their relationship to data from in vitro cell culture and in vivo animal and human studies, are discussed. Low-dose, intermediate-dose, and high-dose therapies are covered. Since in vitro and in vivo screenings of potential cancer drugs are commonplace in the development of cancer chemotherapy, comparisons of the three criteria for effectiveness are important.

Chemical constituents of the aerial parts of Salvia judaica Boiss. from Jordan.

Investigation of the chemical constituents of Salvia judaica growing wild in Jordan led to the isolation and identification of 15 known compounds. These included: luteolin-3'-methyl ether (1), indole-3-carboxyaldehyde (2), p-hydroxybenzaldehyde (3), tricin (4), apigenin (5), methyl isoferuloyl-7-(3,4-dihydroxyphenyl) lactate (6), methyl rosmarinate (7), rosmarinic acid (8), salvigenin (9), ß-sitosterol (10), 3ß, 28-dihydroxyurs-12-ene (11), cirsilineol (12), 2,3-dihydroxyurs-12-en-28-oic acid (13), ß-sitosteryl glucoside (14), and tormentic acid (15). Compounds 6 and 7 exhibited strong radical scavenging and chelating activities as compared to α-tocopherol and ascorbic acid, compound 7 showed a 2-fold greater antioxidant activity as compared to compound 6. Furthermore, low doses of compounds 6 and 7 were able to inhibit the growth of leukemic (HL-60, Jurkat, K562 and CCRF-SB) and solid tumor cells (MCF-7, MDA-MB-231 and Caco-2). Compound 7 showed a ca. 3-4-fold stronger cytotoxicity against the tested cells as compared to compound 6.

Rheumatoid Arthritis: A Brief Overview of the Treatment.

Rheumatoid arthritis (RA) is a chronic, inflammatory, systemic autoimmune disease, affecting the joints with varying severity among patients. The risk factors include age, gender, genetics, and environmental exposure (cigarette smoking, air pollutants, and occupational). Many complications can follow, such as permanent joint damage requiring arthroplasty, rheumatoid vasculitis, and Felty syndrome requiring splenectomy if it remains unaddressed. As there is no cure for RA, the treatment goals are to reduce the pain and stop/slow further damage. Here, we present a brief summary of various past and present treatment modalities to address the complications associated with RA.

Antibody responses to P. falciparum Apical Membrane Antigen 1(AMA-1) in relation to haemoglobin S (HbS), HbC, G6PD and ABO blood groups among Fulani and Masaleit living in Western Sudan.

Fulani and Masaleit are two sympatric ethnic groups in western Sudan who are characterised by marked differences in susceptibility to Plasmodium falciparum malaria. It has been demonstrated that Glucose-6-phosphate dehydrogenase (G6PD) deficiency and Sickle cell trait HbAS carriers are protected from the most severe forms of malaria. This study aimed to investigate a set of specific IgG subclasses against P. falciparum Apical Membrane Antigen 1 (AMA-1 3D7), haemoglobin variants and (G6PD) in association with malaria susceptibility among Fulani ethnic group compared to sympatric ethnic group living in Western Sudan. A total of 124 children aged 5-9 years from each tribe living in an area of hyper-endemic P. falciparum unstable malaria transmission were recruited and genotyped for the haemoglobin (Hb) genes, (G6PD) and (ABO) blood groups. Furthermore, the level of plasma IgG antibody subclasses against P. falciparum antigen (AMA-1) were measured using enzyme linked immunosorbent assays (ELISA). Higher levels of anti-malarial IgG1, IgG2 and IgG3 but not IgG4 antibody were found in Fulani when compared to Masaleit. Individuals carrying the HbCC phenotype were significantly associated with higher levels of IgG1 and IgG2. Furthermore, individuals having the HbAS phenotype were associated with higher levels of specific IgG2 and IgG4 antibodies. In addition, patients with G6PD A/A genotype were associated with higher levels of specific IgG2 antibody compared with those carrying the A/G and G/G genotypes. The results indicate that the Fulani ethnic group show lower frequency of HbAS, HbSS and HbAC compared to the Masaleit ethnic group. The inter-ethnic analysis shows no statistically significant difference in G6PD genotypes (P value = 0.791). However, the intra-ethnic analysis indicates that both ethnic groups have less A/A genotypes and (A) allele frequency of G6PD compared to G/G genotypes, while the HbSA genotype was associated with higher levels of IgG2 (AMA-1) and IgG4 antibodies. In addition, patients carrying the G6PD A/A genotype were associated with higher levels of specific IgG2 antibody compared with those carrying the A/G and G/G genotypes. The present results revealed that the Fulani ethnic group has statistically significantly lower frequency of abnormal haemoglobin resistant to malaria infection compared to the Masaleit ethnic group.

Applications of nanoparticle systems in drug delivery technology.

The development of nanoparticle-based drug formulations has yielded the opportunities to address and treat challenging diseases. Nanoparticles vary in size but are generally ranging from 100 to 500 nm. Through the manipulation of size, surface characteristics and material used, the nanoparticles can be developed into smart systems, encasing therapeutic and imaging agents as well as bearing stealth property. Further, these systems can deliver drug to specific tissues and provide controlled release therapy. This targeted and sustained drug delivery decreases the drug related toxicity and increase patient's compliance with less frequent dosing. Nanotechnology has proven beneficial in the treatment of cancer, AIDS and many other disease, also providing advancement in diagnostic testing.

Protective effect of metoclopramide against organophosphate-induced apoptosis in the murine skin fibroblast L929.

This study was performed to evaluate the protective efficacy of metoclopramide (MCP) against the organophosphates paraoxon (POX)- and malathion (MLT)-induced apoptosis in the murine L929 skin fibroblasts. L929 cells were exposed to either POX (10 nm) or 1.0 µm MLT in the absence and presence of increased concentrations of MCP. The protective effect of MCP on these organophosphate-stimulated apoptotic events was evaluated by flow cytometry analysis after staining with annexin-V/propidium iodide, processing and activation of the executioner caspase-3, cleavage of the poly-ADP ribose polymerase, fragmentation of the nucleosomal DNA and disruption of the mitochondrial membrane potential (Δψ). Our results showed that increased doses of MCP alone (≥10 µm) did not induce apoptosis or activation of caspase-3. Pretreatment of the cells with MCP attenuated all the apoptotic events triggered by the organophosphate compounds in a dose-dependent manner reaching ~70-80% protection when they were preincubated at 1 and 5 µm of the drug before the addition of POX and MLT, respectively. Interestingly, MCP did not offer a significant protective effect against the cytotoxicity of tumor necrosis factor-α, cisplatinum, etoposide or paclitaxel, which stimulate apoptosis by various mechanisms, suggesting that the anti-apoptotic effect of the drug is specific to organophosphates. The strong and specific anti-apoptotic activity of subclinical doses of MCP against the cytotoxicity of organophosphate compounds suggests its potential clinical application in treating their poisoning.

Towards personalized medicine of colorectal cancer.

Efforts in colorectal cancer (CRC) research aim to improve early detection and treatment for metastatic stages which could translate into better prognosis of this disease. One of the major challenges that hinder these efforts is the heterogeneous nature of CRC and involvement of diverse molecular pathways. New large-scale 'omics' technologies are making it possible to generate, analyze and interpret biological data from molecular determinants of CRC. The developments of sophisticated computational analyses would allow information from different omics platforms to be integrated, thus providing new insights into the biology of CRC. Together, these technological advances and an improved mechanistic understanding might allow CRC to be clinically managed at the level of the individual patient. This review provides an account of the current challenges in CRC management and an insight into how new technologies could allow the development of personalized medicine for CRC.

Comprehensive Analysis of the Chemical Composition and In Vitro Cytotoxic Mechanisms of Pallines Spinosa Flower and Leaf Essential Oils Against Breast Cancer Cells.

BACKGROUND/AIMS: In our quest for new natural anticancer agents, we studied the cytotoxicity of the essential oils extracted from flowers and leaves of Pallines spinosa. METHODS: The essential oils were extracted by hydrodistillation and solid phase microextraction (SPME) from flowers and leaves of the plant and their composition was determined by GC/GC-MS. The cytotoxicity of the oils was evaluated against MCF-7 and MDA-MB-231 breast adenocarcinomas, and the non-cancerous MCF-10-2A cells, using a flow cytometry-based assay Apoptosis was evaluated by flow cytometry, nuclear staining, caspases activation, and Western blotting techniques, and cell cycle by measuring DNA contents. RESULTS: The hydrodistilled flower oil contained mainly sesquiterpenes (96.39%), while the leaf sample was dominated by oxygenated-sesquiterpenes (51.60%) and sesquiterpene-hydrocarbons (34.06%). In contrast, the SPME oil contained mainly monoterpene-hydrocarbons (44.09%) and sesquiterpene-hydrocarbons (34.15%) in the flower and leaf samples, respectively. The cytotoxicity of the flower oil against MCF-7 (IC50 0.25 ± 0.03 µg/mL) and MDA-MB-231 (IC50 0.21 ± 0.03 µg/mL) was much stronger than the leaf oil (IC50 2.4 ± 0.5 µg/mL and 1.5 ± 0.1 µg/mL, respectively). The toxicity of the flower oil was ∼5 to 8-times less in normal MCF-10-2A (IC50 1.3 ± 0.2 µg/mL) and blood mononuclear cells (2.80 ± 0.45 µg/mL) as compared to breast and hematological cancer cells, respectively. Both oils induced a caspase-dependent and -independent apoptosis in MCF-7 and MDA-MB-231 cells, and altered the levels of Bcl-2 and Bax proteins. In addition, the oils arrested cell cycle in both cancer cell lines at G0/G1 phase by modulating the expression of cyclin D1, CDK4 and p21 proteins. CONCLUSION: The cytotoxicity of P. spinosa oils were mediated by apoptosis and cell cycle arrest, suggesting the potential use of their bioactive compounds as natural anticancer compounds.

Composition, Antioxidant, and Cytotoxic Activities of the Essential Oils from Fresh and Air-Dried Aerial Parts of Pallenis spinosa.

This study was performed to determine the chemical composition, antioxidant and cytotoxic effects of essential oils extracted from the aerial parts of fresh (F-PSEO) and air-dried (D-PSEO) Pallenis spinosa. The composition of the oils was analyzed by gas chromatography (GC) and GC/mass spectrometry, the antioxidant activity by free radical scavenging and metal chelating assays, and their cytotoxicity by a flow cytometry analysis. The primary components in both oils were sesquiterpene hydrocarbons and oxygentated sesquiterpenes. F-PSEO contained 36 different compounds; α-cadinol (16.48%), germacra-1(10),5-diene-3,4-diol (14.45%), γ-cadinene (12.03%), and α-muurolol (9.89%) were the principal components. D-PSEO contained 53 molecules; α-cadinol (19.26%), δ-cadinene (13.93%), α-muurolol (12.88%), and germacra-1(10),5-diene-3,4-diol (8.41%) constituted the highest percentages. Although both oils exhibited a weak radical scavenging and chelating activity, compared to α-tocopherol and ascorbic acid, D-PSEO showed a 2-fold greater antioxidant activity than F-PSEO. Furthermore, low doses of F-PSEO were able to inhibit the growth of leukemic (HL-60, K562, and Jurkat) and solid tumor cells (MCF-7, HepG2, HT-1080, and Caco-2) with an IC50 range of 0.25 - 0.66 µg/ml and 0.50 - 2.35 µg/ml, respectively. F-PSEO showed a ca. 2 - 3-fold stronger cytotoxicity against the tested cells than D-PSEO. The potent growth inhibitory effect of the plant essential oil encourages further studies to characterize the molecular mechanisms of its cytotoxicity.

Utility of cytokine, adhesion molecule and acute phase proteins in early diagnosis of neonatal sepsis.

BACKGROUND AND AIM: Neonatal infection, including bacterial sepsis, is a major health care issue with an annual global mortality in excess of one million lives. Therefore, this study aimed to evaluate the potential diagnostic value of C-reactive protein (CRP), E-selectin, procalcitonin (PCT), interleukins-6 (IL-6), and tumor necrosis factor-α (TNF-α) both independently and in combination for the diagnosis of neonatal sepsis in its earliest stages. MATERIALS AND METHODS: A total of 320 subjects were included in this study. A prospective cross-sectional study was conducted among neonates admitted to Neonatal Intensive Care Unit at King Abdulaziz Medical City, Riyadh, KSA during January 2013 to August 2015, the study based on three study groups categorized according to clinical symptoms and blood culture result. Study groups include healthy control neonates (n = 80), clinical sepsis (CS) group (n = 80) with clinical signs of sepsis but their blood culture was negative, and sepsis group with clinical signs of sepsis and their blood culture was positive. RESULTS: The study observed significant difference in plasma levels of CRP, IL-6, TNF-α, E-selectin, and PCT in patients group when compared with control group (P < 0.001). Furthermore, the levels are significantly different between patient groups including CS and neonatal sepsis group. Moreover, result observed significant difference in CRP and IL-6 in early onset sepsis (EOS) when compared with late onset sepsis (LOS) neonates (P < 0.001 and 0.01), respectively, while there were no significant difference in TNF-α, E-selectin, and PCT between EOS and LOS (P = 0.44, 0.27 and 0.24), respectively. Regarding biomarkers accuracy, the result showed that CRP has the best diagnostic accuracy with cutoff value of 3.6 ng/ml (sensitivity 78% and specificity of 70%). The best combination is shown with CRP and IL-6 in which sensitivity increased to 89% and specificity to 79%. CONCLUSION: It was concluded that infected new-born babies have a higher E-selectin, PCT, IL-6, TNF-α, and CRP compared with the neonates with CS and control. IL-6, TNF-α, and CRP should be measured in combination for mare diagnostic accuracy in neonatal sepsis. Likewise, PCT should be investigated as a part of sepsis screening for all suspected neonates.

New flavonol glycoside from Scabiosa prolifera L. aerial parts with in vitro antioxidant and cytotoxic activities.

Phytochemical investigation of the chemical constituents of the aerial parts of Scabiosa prolifera L. led to the isolation of one new flavonol glycoside, kaempferol-3-O-(4″,6″-di-E-p-coumaroyl)-ß-D-galactopyranoside (1), along with ten other known compounds including luteolin-7-O-(2″-O-ethyl-ß-glucopyranoside), ß-sitosterol, ß-sitosterylglucoside, ursolic acid, corosolic acid, ursolic acid 3-O-ß-D-arabinopyranoside, apigenin, methyl-α-D-glucopyranoside, luteolin-7-O-ß-glucopyranoside and isoorientin. The structures of all isolated compounds were established using chemical methods and spectroscopic methods including IR, UV, NMR (1D and 2D) and HRESIMS. All compounds were isolated for the first time from the plant. The antioxidant and cytotoxic activities of compounds 1 and 2 were also investigated.

Cytotoxic activity of the novel heterocyclic compound G-11 is primarily mediated through intrinsic apoptotic pathway.

Natural and chemically synthesized heterocyclic compounds have been explored for their potential use as anticancer agents. We had synthesized non-natural heterocyclic analogs and evaluated their anti-tumor activity by measuring effect on cell proliferation and induction of apoptosis in different cell lines. Previously, we identified a pyrazole-containing compound (G-11) showing cytotoxic effect towards leukemia and lymphoma cell lines. In this study, we further investigated the mechanistic aspects of anticancer properties of G-11 in HL-60 cell line. We demonstrated that cytotoxic effect of G-11 is mediated by caspase-dependent apoptosis. However, the involvement of mitochondrial dysfunction induced by G-11 was independent of caspases. G-11 triggered generation of ROS, caused disruption of mitochondrial transmembrane potential, increased release of cytochrome c to the cytosol, and altered the expression of Bcl-2 and Bax proteins. These results suggest significant involvement of intrinsic apoptotic pathway. This study comprehensively details the possible mechanisms of action of a novel heterocyclic compound which could find its potential use as an anticancer agent.

Neurocysticercosis: A case report and brief review.

Neurocysticercosis (NCC) is one of the seven neglected endemic zoonoses targeted by the World Health Organization. It is considered a common infection of the nervous system caused by the Taenia solium and is known to be the primary cause of preventable epilepsy in many developing countries. NCC is commonly resulted by the ingestion of Taenia solium eggs after consuming undercooked pork, or contaminated water. The parasite can grow in the brain and spinal cord within the nervous system, causing severe headache and seizures beside other pathological manifestations. Immigration and international travel to endemic countries has made this disease common in the United States. NCC can be diagnosed with computed tomography and magnetic resonance imaging of the brain. The treatment of the NCC including cysticidal drugs (e.g., albendazole and praziquantel), and neurosurgical procedure, depending upon the situation. A patient of Asian origin came to our clinic with complaints of dizziness, headaches and episodes seizures for the past twelve years without proper diagnosis. The computed tomography and magnetic resonance imaging scans indicated multilobulated cystic mass in the brain with the suspicion of neurocysticercosis.

Novel anticancer compound [trifluoromethyl-substituted pyrazole N-nucleoside] inhibits FLT3 activity to induce differentiation in acute myeloid leukemia cells.

Anticancer properties of chemically synthesized compounds have continuously been optimized for better efficacy and selectivity. Derivatives of heterocyclic compounds are well known to have selective antiproliferative effect against many types of cancer. In this study, we investigated the ability of an indigenously synthesized anticancer molecule, G-11 [1-(2",3",4",6"-Tetra-O-acetyl-ß-D-glucopyranosyl)-4-(3'-trifluoromethylphenylhydrazono)-3-trifluoromethyl-1,4-dihydropyrazol-5-one], to cause selective cytotoxicity and induce differentiation in the acute myeloid leukemia HL-60 cells. G-11 was able to exert cytotoxic effect on hematological (Jurkat, U937, K562, HL-60, CCRF-SB) and solid tumor (MCF-7, HepG2, HeLa, Caco-2) cell lines, with IC50 values significantly lower than noncancerous cells (HEK-293, BJ and Vero) and normal peripheral blood mononuclear cells. G-11 induced differentiation of HL-60 cells to granulocytes and monocytes/macrophages by inhibiting the activation of FLT3 (CD135 tyrosine kinase). ITD-FLT3 mutation found in many acute myeloid leukemia patients could also be targeted by G-11 as exhibited by its inhibitory effect on MOLM-13 and MV4-11 cell lines. Molecular docking studies suggest the involvement of Leu616, Asp698, Cys694 and Cys828 residues in binding of G-11 to FLT3. The ability of G-11 to cause selective cytotoxicity and induce differentiation in cancer cells could be clinically relevant for therapeutic gains.

Altered Lamin A/C splice variant expression as a possible diagnostic marker in breast cancer.

BACKGROUND: Lamin A/C alternative splice variants (Lamin A, Lamin C, Lamin AΔ10 and Lamin AΔ50) have been implicated in cell cycle regulation, DNA replication, transcription regulation, cellular differentiation, apoptosis and aging. In addition, loss of Lamin A/C expression has been observed in several cancers, including breast cancer, and it has been found that Lamin A/C suppression may lead to cancer-like aberrations in nuclear morphology and aneuploidy. Based on these observations, we hypothesized that Lamin A/C transcript variant quantification might be employed for the diagnosis of breast cancer. METHODS: Newly designed TaqMan qRT-PCR assays for the analysis of Lamin A/C splice variants were validated and their use as biomarkers for the diagnosis of breast cancer was assessed using 16 normal breast tissues and 128 breast adenocarcinomas. In addition, the expression levels of the Lamin A/C transcript variants were measured in samples derived from seven other types of cancer. RESULTS: We found that the expression level of Lamin C was significantly increased in the breast tumors tested, whereas the expression levels of Lamin A and Lamin AΔ50 were significantly decreased. No significant change in Lamin AΔ10 expression was observed. Our data also indicated that the Lamin C : Lamin A mRNA ratio was increased in all clinical stages of breast cancer. Additionally, we observed increased Lamin C : Lamin A mRNA ratios in liver, lung and thyroid carcinomas and in colon, ovary and prostate adenocarcinomas. CONCLUSIONS: From our data we conclude that the Lamin C : Lamin A mRNA ratio is increased in breast cancer and that this mRNA ratio may be of diagnostic use in all clinical stages of breast cancer and, possibly, also in liver, lung, thyroid, colon, ovary and prostate cancers.

Quantification of insulin receptor mRNA splice variants as a diagnostic tumor marker in breast cancer.

BACKGROUND: The mature human insulin receptor (INSR) has two isoforms: The A isoform and the B isoform. INSR upregulation has been suggested to play a role in cancer. OBJECTIVE: To establish quantitative PCR method for INSR transcript variants and examine their differential expression as a diagnostic tumor marker in breast cancer. METHODS: The differential expression of IR-A and IR-B were evaluated by TaqMan qRT-PCR assay in the commercially available Breast Cancer Disease cDNA and Cancer Survey cDNA arrays. RESULTS: The mRNA expression levels of IR-A was statistically significantly higher in breast cancer when compared to normal breast tissue while IR-B mRNA expression was down regulated significantly in breast cancer. Stratification of patients into groups according to metastatic stages indicated statistically significantly higher levels of IR-A mRNA in clinical stage (CS)-IV, and lower IR-B levels in CS-IIA, CS-IIIB and CS-IIIC. However, IR-A:IR-B ratio showed a statistically significant increase in all stages. Cancer Survey cDNA array demonstrated lower levels of IR-B mRNA in breast adenocarcinoma, liver carcinoma and lung carcinoma only while IR-A expression was significantly altered in kidney carcinoma without any significant differences in IR-A:IR-B ratios. CONCLUSIONS: The results demonstrate an increased IR-A:IR-B ratio in all clinical stages of breast cancer. Thus, IR-A:IR-B ratio may have a diagnostic biomarker utility in breast cancer.

New isoflavones from Gynandriris sisyrinchium and their antioxidant and cytotoxic activities.

Chemical investigation of Gynandriris sisyrinchium (L.) Parl growing in Jordan resulted in the isolation and characterization of a total of twelve compounds two of which are reported here for the first time in nature. These new compounds included the isoflavones; 3'-methyl tenuifone (2) and gynandrinone (5). In addition, ten known compounds including; ß-sitosterol (1), 7,3'-dimethoxy-5,6,4'-trihydroxyisoflavone (3), iristectorigenin (4), hispidulin (6), galangustin (7), 6-hydroxybiochanin A (8), ursolic acid (9), ladanetin (10), 4'-O-methylgenistein (11) and ß-sitosterol glucoside (12) are also reported here for the first time from G. sisyrinchium. The isolated compounds were characterized by different spectroscopic methods including NMR (1D and 2D), UV, IR and MS (HRESIMS and EIMS). The antioxidant and cytotoxic activities of isoflavones 2, 3 and 5 were investigated. Compound 3 showed the highest antioxidant activity (IC50=17.3µg/mL), as compared to compounds 5 and 2 (IC50=26.7 and 51.7µg/mL, respectively). The cytotoxic activity against the human promyelocytic leukemia HL-60 cells revealed that compound 2 was the most active (40µM). The results indicate that the cytotoxicity of compound 2 is mediated by apoptosis.

The anticancer activity of the substituted pyridone-annelated isoindigo (5'-Cl) involves G0/G1 cell cycle arrest and inactivation of CDKs in the promyelocytic leukemia cell line HL-60.

BACKGROUND/AIMS: The antileukemic potential of isoindigos make them desired candidates for understanding their mechanism of action. We have recently synthesized a novel group of pyridone-annelated isoindigos and identified the derivative 5'-Cl that is cytotoxic to various cancer cell lines. In the present study, we analyzed the effect of this compound on cell cycle of the promyelocytic leukemia cell line HL-60. METHODS: HL-60 cells were treated with 5'-Cl and its effect on cell cycle stages were determined by flow cytometry. Expression of cyclins, cyclin dependent kinases (CDKs) and cyclin kinase inhibitors (CKIs) were determined by Western blotting, and activation of CDKs was studied using kinase assays. RESULTS: 5'-Cl remarkably arrested cell cycle in HL-60 cells at the G0/G1 phase in a dose and time-dependent manner. Furthermore, 5'-Cl treatment significantly inhibited expression of D-cyclins, CDK2 and CDK4 and suppressed phosphorylation of the retinoblastoma protein Rb, whereas it increased the level of CKI p21. Molecular modelling experiments show that 5'-Cl may compete with ATP for binding to the catalytic subunit of CDK2 and CDK4 that could lead to inhibition of these enzymes. Indeed, 5'-Cl inhibited the kinase activity of CDK2 and CDK4 both in cell free systems and in treated cells. 5'-Cl also inhibited cell cycle progression in several other tumor cell lines. CONCLUSION: We demonstrate the potent inhibitory effects of 5'-Cl on HL-60 cells could be mediated by arresting cells in the G0/G1 phase.