Anagallis arvensis Induces Apoptosis in HL-60 Cells Through ROS-Mediated Mitochondrial Pathway.

The present study was taken up to evaluate the apoptosis inducing ability of alcoholic extract of whole plant of Anagallis arvensis (AAE) in HL-60 cells. We observed time and concentration dependent decrease in cell viability after treatment with AAE. Fluorescent staining and scanning electron micrographs of treated HL-60 cells demonstrated chromatin condensation, nuclear fragmentation and formation of apoptotic blebs. There was a marked increase in hypodiploid population of cells as observed by cell cycle analysis. Annexin V-FITC/PI also depicted the presence of apoptotic cells. Anti-apoptotic protein Bcl-2 was observed to be decreased by 62% at 20 µg/ml concentration and a significant increase in ROS production up to 6.9-fold was observed in time dependent manner. In addition, alteration in mitochondrial membrane potential was observed, which was followed by cytochrome c release to cytoplasm. Activated levels of mitochondrial downstream pathway protein namely Caspase-3 and 9, were detected in treated HL-60 cells by colorimetric analysis. DNA ladder formation, a biochemical hallmark of apoptosis was also observed in treated HL-60 cells. The results of the present study support the apoptotic potential of AAE and probability of its promising role in development as effective anticancer agent against leukemia cells.

Immunosuppressive potential of Botryosphaeria dothidea, an endophyte isolated from Kigelia africana.

CONTEXT: For years, natural products from microbes have been used as drugs. Endophytes are the most important fungi that produce many novel metabolites for potential use in pharmacology and agriculture. OBJECTIVE: The objective of the present study was to explore new endophytes for novel natural products. MATERIALS AND METHODS: An endophyte BAK-I was isolated from the bark of Kigelia africana (Lam.) Beneth (Bignoniaceae). BAK-I was characterized morphologically and on the basis of ITS-5.8S rDNA sequences. BAK-I was fermented to yield an extract, which was evaluated for its anticancer, antimicrobial, and immunomodulatory activities, using MTT, agar well-diffusion, tube dilution method, lymphocyte proliferation, and pro-inflammatory cytokines (TNF-α) (by macrophages) evaluation assays. For lymphocyte proliferation and pro-inflammatory cytokines studies, four concentrations were evaluated 10, 30, 100, and 1000 µg/mL and the experiments were conducted for 72 and 48 h, respectively. RESULTS AND DISCUSSION: The BAK-I showed pink cottony growth. SEM studies showed smooth fusoid-oblong conidia with a truncated base. Furthermore, ITS-5.8S rDNA sequence showed 99% homology with the Botryosphaeria dothidea strain suggesting that the endophyte is a strain of the genus Botryosphaeria. Less than 50% growth inhibition of SF295, Lung A-549, and THP-1 cancer cell lines after treatment with BAK-I extract suggested that it did not have significant cytotoxic potential, whereas it is bactericidal for Gram-positive pathogens MRSA and VRE with MIC value 200 and 250 µg/mL, respectively. To elucidate its immunomodulation potential, splenocyte proliferation studies showed that BAK-1 suppressed the T cell proliferation by 50%. TNF-α evaluation studies also showed that the extract inhibited TNF-α production in a concentration-dependent manner suggesting that it had immunosuppressive potential. Inhibition at 10 µg/mL was found to be 55% as against 48% using ß-methasone. CONCLUSION: The results suggested that BAK-I extract can be used as a potential immunosuppressive agent.

Cell specific apoptosis by RLX is mediated by NFκB in human colon carcinoma HCT-116 cells.

BACKGROUND: Resistance to chemotherapy represents a major obstacle in correcting colorectal carcinomas (CRC). Inspite of recent advances in the treatment of metastatic disease, the prognosis of the patients remains poor. RLX, a vasicinone analogue has been reported to possess potent bronchodilator, anti-asthmatic and anti-inflammatory properties. However, its anti-cancer activity is unknown. RESULTS: Here, we report for the first time that RLX has anti-cancer property against panel of human cancer cell lines and most potent activity was found against HCT-116 cells with IC50 value of 12 µM and have further investigated the involvement of NFκB and caspase-3 in RLX action in CRC apoptosis. Following RLX and BEZ-235 treatment in HCT-116, we observed significant down-regulation of NFκB (1 to 0.1 fold) and up-regulation of caspase-3 (1 to 2 fold) protein expressions. Additionally, morphological studies revealed membrane blebbing, cell shrinkage, chromatin condensation and finally apoptosis in HCT-116 cells. CONCLUSIONS: Overall, these findings indicate that RLX is a potent small molecule which triggers apoptosis, and promising potential candidate to be a chemotherapeutic agent.

Dual targeted polymeric nanoparticles based on tumor endothelium and tumor cells for enhanced antitumor drug delivery.

Some specific types of tumor cells and tumor endothelial cells represented CD13 proteins and act as receptors for Asn-Gly-Arg (NGR) motifs containing peptide. These CD13 receptors can be specifically recognized and bind through the specific sequence of cyclic NGR (cNGR) peptide and presented more affinity and specificity toward them. The cNGR peptide was conjugated to the poly(ethylene glycol) (PEG) terminal end in the poly(lactic-co-glycolic) acid PLGA-PEG block copolymer. Then, the ligand conjugated nanoparticles (cNGR-DNB-NPs) encapsulating docetaxel (DTX) were synthesized from preformed block copolymer by the emulsion/solvent evaporation method and characterized for different parameters. The various studies such as in vitro cytotoxicity, cell apoptosis, and cell cycle analysis presented the enhanced therapeutic potential of cNGR-DNB-NPs. The higher cellular uptake was also found in cNGR peptide anchored NPs into HUVEC and HT-1080 cells. However, free cNGR could inhibit receptor mediated intracellular uptake of NPs into both types of cells at 37 and 4 °C temperatures, revealing the involvement of receptor-mediated endocytosis. The in vivo biodistribution and antitumor efficacy studies indicated that targeted NPs have a higher therapeutic efficacy through targeting the tumor-specific site. Therefore, the study exhibited that cNGR-functionalized PEG-PLGA-NPs could be a promising approach for therapeutic applications to efficient antitumor drug delivery.

Fruits and barks extracts of Zanthozyllum heitzii a spice from Cameroon induce mitochondrial dependent apoptosis and Go/G1 phase arrest in human leukemia HL-60 cells.

BACKGROUND: Zanthoxylum heitzii is a spice used to prepare several dishes and to treat tumors, syphilis, malaria, cardiac palpitations, urogenital infections in the west region of Cameroon, but the antitumor mechanisms and chemical composition are not yet investigated. This study was aimed to determine the antiproliferative effects of four extracts from the fruits and barks of Zanthoxyllum heitzii (Rutaceae) on apoptosis in human promyelocytic cells, their mechanisms and the chemical composition. The 3-(4, 5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the fifty percent inhibition (IC50) concentration of the cell lines after treatment. The effect on morphology was observed using a light or fluorescence microscopy. The rate of apoptosis and the cell cycle were measured using flow cytometry (FCM). The phytochemical analysis of the extract was carried with HPLC/MS methods. RESULTS: The phytochemical analysis of the extracts indicated the presence of four known polyphenols (Syringic acid, Juglon, Luteolin and Myricetin) in both fruits and barks of Z. heitzii but in different quantities. Syringic acid and Myricetin concentrations were between 17-21 fold higher in the fruits than the stem bark. Rhamnetin (393.35 µg/mL) and Oleuropein (63.10 µg/mL) were identified only in the stem barks of Z. heitzii. Among the four extracts tested for cytotoxicity properties, only the methanol extract of fruits and barks significantly inhibited cell proliferation of HL-60 cells with IC50 value of 20 µg/mL and 12 µg/mL respectively. HL-60 cells treated with Z. heitzii extracts significantly produced reactive oxygen species (ROS) with concurrent loss of mitochondrial membrane potential (MMP). Modifications in the DNA distribution and enhanced of G1/G0 phase cell cycle arrest were observed in a concentration dependent manner. CONCLUSIONS: Polyphenols from Z. heitzii plant exert inhibitory effect on HL-60 cells through the reactive oxygen species (ROS) generation, loss of mitochondrial membrane potential and cell cycle destabilization.

Cytotoxic and antimicrobial activities of endophytic fungi isolated from Bacopa monnieri (L.) Pennell (Scrophulariaceae).

BACKGROUND: Endophytes, which reside in plant tissues, have the potential to produce novel metabolites with immense benefits for health industry. Cytotoxic and antimicrobial activities of endophytic fungi isolated from Bacopa monnieri (L.) Pennell were investigated. METHODS: Endophytic fungi were isolated from the Bacopa monnieri. Extracts from liquid cultures were tested for cytotoxicity against a number of cancer cell lines using the MTT assay. Antimicrobial activity was determined using the micro dilution method. RESULTS: 22% of the examined extracts showed potent (IC50 of <20 µg/ml) cytotoxic activity against HCT-116 cell line. 5.5%, 11%, 11% of the extracts were found to be cytotoxic for MCF-7, PC-3, and A-549 cell lines respectively. 33% extracts displayed antimicrobial activity against at least one test organism with MIC value 10-100 µg/ml. The isolate B9_Pink showed the most potent cytotoxic activity for all the cell lines examined and maximum antimicrobial activity against the four pathogens examined which was followed by B19. CONCLUSIONS: Results indicated the potential for production of bioactive agents from endophytes of Bacopa monnieri.

Antiproliferative activity and induction of apoptosis by Annona muricata (Annonaceae) extract on human cancer cells.

BACKGROUND: Annona muricata (A. muricata) is widely distributed in Asia, Africa and South America. Different parts of this plant are used to treat several diseases in Cameroon. The aim of this study is to determine the in vitro anti-proliferative effects and apoptotic events of A. muricata extracts on HL-60 cells as well as to quantify its phenols content. METHODS: The cell viability was measured by using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay while the changes in morphology of HL-60 cells, membrane mitochondrial potential (MMP) and the cell cycle were used for assessment apoptosis induction. RESULTS: The results show that the concentration of phenols, flavonoids and flavonols in the extracts varied depending on the part of the plant. All the extracts tested inhibited the proliferation of HL-60 cells in a concentration dependent manner with IC50 varied from 6-49 µg/mL. The growth inhibition of the cells by extracts was associated with the disruption of MMP, reactive oxygen species (ROS) generation and the G0/G1 cell arrest. CONCLUSION: These findings suggest that the extracts from A. muricata have strong antiproliferation potential and can induce apoptosis through loss of MMP and G0/G1 phase cell arrest.

Cytotoxic compounds from the leaves of Garcinia polyantha.

A new compound, named banganxanthone C (=12-(1,1-dimethylprop-2-en-1-yl)-5,10-dihydroxy-9-methoxy-2-methyl-2-(4-methylpent-3-en-1-yl)-2H,6H-pyrano[3,2-b]xanthen-6-one; 4), together with five known compounds, were isolated from the leaves of Garcinia polyantha. The structures of the compounds were elucidated on the basis of 1D- and 2D-NMR spectroscopy. Among the known compounds, two were xanthones, one was a pentacyclic triterpene, one sterol, and one benzophenone derivative. Isoxanthochymol (2) and 4-[(2E)-3,7-dimethylocta-2,6-dien-1-yl]-1,5,8-trihydroxy-3-methoxy-9H-xanthen-9-one (3) exhibited significant antiproliferative activity against the leukemia cell line TPH-1 with IC50 inhibition values of 1.5 and 2.8 µg/ml, respectively. The cytotoxic activity was found to be related to apoptosis induction.

In vitro anticancer activity of extracts of Mentha Spp. against human cancer cells.

In vitro anticancer potential of methanolic and aqueous extracts of whole plants of Mentha arvensis, M. longifolia, M. spicata and M. viridis at concentration of 100 µg/ml was evaluated against eight human cancer cell lines--A-549, COLO-205, HCT-116, MCF-7, NCI-H322, PC-3, THP-1 and U-87MG from six different origins (breast, colon, glioblastoma, lung, leukemia and prostate) using sulphorhodamine blue (SRB) assay. Methanolic extracts of above-mentioned Mentha Spp. displayed anti-proliferative effect in the range of 70-97% against four human cancer cell lines, namely COLO-205, MCF-7, NCI-H322 and THP-1; however, aqueous extracts were found to be active against HCT-116 and PC-3. The results indicate that Mentha Spp. contain certain constituents with cytotoxic properties which may find use in developing anticancer agents.

In vitro cytotoxic activity of leaves extracts of Holarrhena antidysenterica against some human cancer cell lines.

In vitro cytotoxic potential of extracts (95% and 50% ethanolic extract and hot water extract at concentration of 100 microg/ml) from leaves of Holarrhena antidysenterica was evaluated against fourteen human cancer cell lines--A-549, COLO-205, DU-145, HeLa, HEP-2, IMR-32, KB, MCF-7, NCI-H23, OVCAR-5, SiHa, SK-N-MC, SW-620 and ZR-75-1 from nine different tissues (breast, colon, cervix, CNS, lung, liver, oral, ovary and prostate) using SRB assay. The 95% ethanolic extract displayed maximum anti-proliferative effect in the range of 73-92% against eight human cancer cell lines, while 50% ethanolic extract showed cytotoxic activity in the range of 70-94% against seven human cancer cell lines. However, the hot water extract did not show any activity. Among the fractions of 95% and 50% ethanolic extract, significant cytotoxic activity was found in the chloroform soluble fraction of 95% ethanolic extract at 100 microg/ml; it inhibited the growth in the range of 71-99% of seven human cancer cell lines from five different tissues viz., OVCAR-5 (ovary), HT-29 (colon), SK-N-MC (neuroblastoma), HEP-2 (liver), COLO-205 (colon), NIH-OVCAR-3 (ovary) and A-549 (lung). The cytotoxic activity of chloroform soluble fraction was found to be higher than 5-flurouracil, adriamycin, mitomycin-c and paclitaxel (anticancer drugs used as positive controls). Further in vivo studies and identification of active components from the chloroform fraction and their exact mechanism of action could be useful in designing new anticancer therapeutic agents.

Emerging Role of Autophagy in Governing Cellular Dormancy, Metabolic Functions, and Therapeutic Responses of Cancer Stem Cells.

Tumors are composed of heterogeneous populations of dysregulated cells that grow in specialized niches that support their growth and maintain their properties. Tumor heterogeneity and metastasis are among the major hindrances that exist while treating cancer patients, leading to poor clinical outcomes. Although the factors that determine tumor complexity remain largely unknown, several genotypic and phenotypic changes, including DNA mutations and metabolic reprograming provide cancer cells with a survival advantage over host cells and resistance to therapeutics. Furthermore, the presence of a specific population of cells within the tumor mass, commonly known as cancer stem cells (CSCs), is thought to initiate tumor formation, maintenance, resistance, and recurrence. Therefore, these CSCs have been investigated in detail recently as potential targets to treat cancer and prevent recurrence. Understanding the molecular mechanisms involved in CSC proliferation, self-renewal, and dormancy may provide important clues for developing effective therapeutic strategies. Autophagy, a catabolic process, has long been recognized to regulate various physiological and pathological processes. In addition to regulating cancer cells, recent studies have identified a critical role for autophagy in regulating CSC functions. Autophagy is activated under various adverse conditions and promotes cellular maintenance, survival, and even cell death. Thus, it is intriguing to address whether autophagy promotes or inhibits CSC functions and whether autophagy modulation can be used to regulate CSC functions, either alone or in combination. This review describes the roles of autophagy in the regulation of metabolic functions, proliferation and quiescence of CSCs, and its role during therapeutic stress. The review further highlights the autophagy-associated pathways that could be used to regulate CSCs. Overall, the present review will help to rationalize various translational approaches that involve autophagy-mediated modulation of CSCs in controlling cancer progression, metastasis, and recurrence.

Tiron and trolox potentiate the autophagic cell death induced by magnolol analog Ery5 by activation of Bax in HL-60 cells.

This study describes the mechanism of trolox and tiron induced potentiation of cytotoxicity caused by Ery5, an analog of magnolol, in human myeloid leukemia HL-60 cells. Ery5 induced cytotoxicity in HL-60 cells by involving activation of bax and cleavage of caspase 3, which contributed towards activation of both apoptotic and autophagic pathways. Trolox and tiron, even at non-toxic concentrations, contributed to the cytotoxicity of Ery5 by activation of autophagic proteins like ATG7, ATG12 and LC3-II. Z-VAD-fmk mediated reduction in the cytotoxicity and expression of autophagic proteins, further suggested that autophagy induced by Ery5 is largely dependent upon caspases. Interestingly, Ery5 induced autophagy was accompanied by the downregulation of PI3K/AKT pathway whereas, trolox and tiron strongly enhanced this effect. In addition to that treatment of cells with Ery5, trolox and tiron individually, displayed a marked upregulation of Bax. The involvement of Bax in trolox and tiron induced enhancement of the cytotoxicity of Ery5 was confirmed, when siRNA induced silencing of Bax led to increased viability of the cells and exerted a strong inhibitory effect on LC3-II accumulation and p62 degradation in case of cells treated by the combination of Ery5 with trolox or tiron. Additionally, an important role of PARP in Ery5 mediated cell death has been suggested by PARP silencing experiments, however, potentiation of autophagic cytotoxicity by trolox and tiron did not seem to be dependent on PARP-1. Therefore, Bax seems to play a vital role in trolox and tiron mediated potentiation of autophagic cell death by Ery5 in HL-60 cells.

Cytogenetic profile of aplastic anaemia in Indian children.

BACKGROUND & OBJECTIVES: Aplastic anaemia is a rare haematological disorder characterized by pancytopenia with a hypocellular bone marrow. It may be inherited/genetic or acquired. Acquired aplastic anaemia has been linked to many drugs, chemicals and viruses. Cytogenetic abnormalities have been reported infrequently with acquired aplastic anaemia. Majority of the studies are in adult patients from the West. We report here cytogenetic studies on paediatric patients with acquired aplastic anaemia seen in a tertiary care hospital in north India. METHODS: Patients (n=71, age 4-14 yr) were diagnosed according to the guidelines of International Agranulocytosis and Aplastic Anaemia Study. Conventional cytogenetics with Giemsa Trypsin Giemsa (GTG) banding was performed. Karyotyping was done according to the International System for Human Cytogenetics Nomenclature (ISCN). RESULTS: Of the 71 patients, 42 had successful karyotyping where median age was 9 yr; of these 42, 27 (64.3%) patients had severe, nine (21.4%) had very severe and six (14.3%) had non severe aplastic anaemia. Five patients had karyotypic abnormalities with trisomy 12 (1), trisomy 8 (1) and monosomy 7 (1). Two patients had non numerical abnormalities with del 7 q - and t (5:12) in one each. Twenty nine patients had uninformative results. There was no difference in the clinical and haematological profile of patients with normal versus abnormal cytogenetics although the number of patients was small in the two groups. INTERPRETATION & CONCLUSIONS: Five (11.9%) patients with acquired aplastic anaemia had chromosomal abnormalities. Trisomy was found to be the commonest abnormality. Cytogenetic abnormalities may be significant in acquired aplastic anaemia although further studies on a large sample are required to confirm the findings.

Cytotoxic and antimicrobial activity of selected Cameroonian edible plants.

BACKGROUND: In Cameroon, the use of edible plants is an integral part of dietary behavior. However, evidence of the antimicrobial as well as the cytotoxic effects of many of them has not been investigated. In the present study, aqueous and methanol extracts from barks, seeds, leaves and roots of three Cameroonian edible plants namely Garcina lucida, Fagara heitzii and Hymenocardia lyrata were evaluated for their cytotoxic and antimicrobial activities. METHODS: Antibacterial and antifungal activities were assessed by the broth micro-dilution method meanwhile the cytotoxicity was performed using sulphorhodamine B assay (SRB) against the human leukemia THP-1, the alveolar epithelial A549, prostate cancer PC-3, breast adenocarcinoma MCF-7 and cervical cancer HeLa cell lines. RESULTS: The minimum inhibitory concentration (MIC) values of the seven tested extracts ranged from 62.5 µg/ml to 1000 µg/ml. The methanol (MeOH) extract from the roots of H. lyrata showed the highest antibacterial activity against Gram-positive bacteria S. aureus and S. epidermitis. The best antifungal activity was obtained with the MeOH extract from the leaves of G. lucida against C. tropicalis (MIC value of 62.5 µg/ml). The in vitro antiproliferative activity revealed that, extract from the bark of F. heitzii and extract from H. lyrata roots had significant cytotoxic activity on THP-1 (IC50 8.4 µg/ml) and PC-3 (IC50 9.5 µg/ml) respectively. CONCLUSION: Our findings suggest that Cameroonian spices herein studied could be potentially useful for the development of therapeutic agents against bacterial infections as well as for prostate and leukemia cancer.

Induction of mitochondrial dependent apoptosis and cell cycle arrest in human promyelocytic leukemia HL-60 cells by an extract from Dorstenia psilurus: a spice from Cameroon.

BACKGROUND: The use of edible plants is an integral part of dietary behavior in the West region of Cameroon. Dorstenia psilurus (Moraceae) is widely used as spice and as medicinal plant for the treatment of several diseases in Cameroon. The aim of this study is to investigate the cytotoxic and apoptotic potential of methanol extract of D. psilurus in human promyelocytic leukemia (HL-60) cells and prostate cancer (PC-3) cells. METHODS: Cytotoxicity of D. psilurus extract was tested in HL-60 and PC-3 cells using 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay and flow cytometric methods RESULTS: The methanol extract of D. psilurus have significant in vitro cytotoxic activity in HL-60 cells and PC-3 cells with IC50 value of 12 ± 1.54 µg/ml and 18 ± 0.45 µg/ml respectively after 48 h. The mechanism of antiproliferative activity showed that after 24 h, D. psilurus extract induces apoptosis on HL-60 cells by the generation of reactive oxygen species (ROS) along with concurrent loss of mitochondrial membrane potential, modification in the DNA distribution and enhance of G2/M phase cell cycle. CONCLUSION: The extract induces apoptosis of HL-60 cells associated with ROS production, loss of mitochondrial membrane potential and apoptotic DNA fragmentation.

Are fragile sites "hot-spots": a causative factor in tumor biology.

Genomic integrity of the cancer cell is doubt-full because of fragility on chromosome. Fragile--sites are non-randomly distributed on human genome prone to form gaps or breaks at either pre/or metaphase chromosome arise when cells are exposed to a perturbation of DNA replication process. Cancer cells commonly show various form of "hot spots" including point mutation, chromosome copy number and translocation involving specific gene mutation but the genetic diversity of fragile sites are still not clear. The chromosomal fragile sites (rare & common fragile sites) make the cancer cells not only susceptible to genomic instability but also contribute the process of malignancy due to expansions of microsatellite CGG or AT rich minisatellite. Fragile sites have been implicated due to inter chromosomal amplification events by initiation breakage - fusion cycles. The mechanisms behind these changes give raise to new insight the cytogenetic manifestation of oncogenesis. Fragile sites loci are associated with activation of oncogenesis during cell--cycle analysis. However, these mutations at fragile sites loci might have play a causative or functional role in tumor biology. The topography organization and informatics complexity of the fragile sites remained unexplored due to lack of systematic approach towards molecular cloning of the fragile sites DNA sequences and specific models as not are under taken. The information regarding mode of inheritance of fragile sites are still lacking but the first degree relative specially young proband and maternal side having variable prevalence in different population could be uses as suitable marker for determining genetic predisposition to cancer. This comprehensive review of fragile sites in tumor biology probably helpful to explore to understand the molecular mechanism of carcinogenesis or tumorgenesis.

PARP cleavage and perturbance in mitochondrial membrane potential by 3-α-propionyloxy-ß-boswellic acid results in cancer cell death and tumor regression in murine models.

BACKGROUND: Apoptotic induction in cancer cells has become a major focus of anticancer therapeutics. In this regard, ß-boswellic acids, naturally occurring pentacyclic triterpenes, have demonstrated antiproliferative and cytotoxic effects against different types of cancers. Surprisingly, not much has been reported regarding the chemical modifications or preparation of structural analogs of the key constituents of ß-boswellic acid. AIM: The anticancer activity of 3-α-propionyloxy-ß-boswellic acid (POBA) was investigated and this article reports for the first time that the triterpenoid ring of the boswellic acid derivative POBA is targeting the PI3K pathway. MATERIALS & METHODS: Induction of apoptosis of the semi-synthetic derivative of ß-boswellic acid-POBA in vitro was analyzed using a battery of human cancer cell lines followed by cell cycle phase distribution, further validated by DNA fragmentation, and was found to cause mitochondrial membrane potential loss with ultrastructural changes, as observed by electron microscopy studies and expression study using PARP cleavage, as well as validated by in vivo anti-tumor activity. RESULTS: The cytotoxicity data revealed the sensitivity of various human cancer cell lines of varied tissue origin to ß-boswellic acid, which robustly induced cell cycle arrest, DNA fragmentation and loss of mitochondrial membrane potential. Morphological studies of the effects of POBA revealed loss of surface projections, chromatin condensation, apoptotic body formation and POBA-mediated PARP cleavage. For in vivo therapeutic experiments, murine tumor models were treated with POBA and the treatment resulted in a significantly higher level of growth inhibition and apoptosis was significantly induced. CONCLUSION: These findings demonstrate that acyl substituents/groups in the main skeleton of ß-boswellic acid have the potential to be potent chemotherapeutic agents.

Anti-proliferative effect of leaf extracts of Eucalyptus citriodora against human cancer cells in vitro and in vivo.

Six different extracts from Eucalyptus citriodora leaves were investigated for their anticancer effect. Extracts were prepared using a range of polar and non-polar solvents to leach out maximum active components. Phytochemical analysis of the extracts revealed the presence of anthraquinones, cardiac glycosides, flavonoids, saponins and tannins. Cytotoxic activity of different extracts was tested in vitro against seven human cancer cell lines from seven different tissues, such as SW-620 (colon), HOP-62 (lung), PC-3 (prostate), OVCAR-5 (ovary), HeLa (cervix), IMR-32 (neuroblastoma) and HEP-2 (liver). The ethyl acetate, chloroform and 50% methanolic extract displayed highest anti-proliferative effect in a dose-dependent manner. In vivo anti-tumor activity was evaluated against murine tumor (solid) model of Ehrlich ascites carcinoma and Sarcoma 180. The results showed that ethyl acetate and aqueous extracts suppressed the growth of Ehrlich ascites carcinoma (29.79% and 18.48%, respectively), but showed little growth inhibition in case of Sarcoma 180 (13. 86% and 8.57%, respectively). The activity might be due to the flavonoids, tannins and saponins that are present in all the extracts of the plant. Further investigation is required for the isolation of active principle(s) from the ethyl acetate extract, which has shown significant in vitro and in vivo anticancer potential.

Antitumor efficacy and apoptotic activity of substituted chloroalkyl 1H-benz[de]isoquinoline-1,3-diones: a new class of potential antineoplastic agents.

A series of ten chloroalkyl 1H-benz[de]isoquinoline-1,3-diones (naphthalimides) were synthesized and evaluated for antitumor activity. Amongst them, new compounds 2d and 2i carrying a 6-NO(2) substituent in the aromatic portion of the molecule possessed significant antineoplastic activity. The most active compound 2i had elicited significant cytotoxicity in 15 human tumor cell lines namely Leukemia: MOLT-4, HL-60; Lymphoma: U-937; Colon: 502713, HT-29, SW-620, HCT-15, COLO-205; Liver: Hep-2; Prostate DU-145, PC-3; Breast: MCF-7; Neuroblastoma: IMR-32, SK-N-SH and Ovary: OVCAR-5 out of the 17 cell lines screened. Flow cytometric analysis performed to study the effect of compound 2i on the progression of cell cycle of MOLT-4 cells, revealed rise in sub-G(1) fraction and concomitant accumulation of cells in S and G(2)/M phases, indicating apoptosis, mitotic arrest and/or delay in exit of daughter cells from mitotic cycle respectively. It also induced caspase-mediated apoptosis of MOLT-4 cells in a dose dependant manner. Light and electron microscopic studies revealed characteristic morphology of apoptotic MOLT-4 cells after in vitro treatment with 10 µM concentration of the compound. Apoptosis induction was also observed in HL-60 cells by compounds 2d and 2i to an extent much greater than camptothecin and cis-platin at 10 µM concentration. Both the compounds have shown minimal suppressive effect on human PBMC having high IC(50) values of 3,582 and 1,536 µM respectively. These compounds inhibited DNA and RNA synthesis in murine ascites Sarcoma-180 tumor cells in vitro at 8 µM concentration. Above results indicate promising chemotherapeutic potential of the key compound 2i.

Induction of apoptosis in human promyelocytic leukemia HL60 cells by an extract from Erythrina suberosa stem bark.

In this study, the apoptosis-inducing effect of an alcoholic extract from Erythrina suberosa stem bark (ESB) was investigated using human promyelocytic leukemia HL60 cells. Cell viability was estimated by MTT assay. We found that the ESB inhibited cell proliferation in a dose- and time-dependent manner. A series of well-documented morphological changes, such as cell shrinkage, condensation of nuclear chromatin, and nuclear fragmentation, were observed by fluorescence microscopy. The gold standard scanning electron micrographs showed apoptotic bodies and formation of blebs. Cell cycle analysis showed a significant increase in Sub G(0) population of cells above 50 µg/ml. ESB treatment resulted in a dose-dependent increase in annexin V positive cells. Increase in intracellular ROS production up to sixfold was detected in ESB-treated HL60 cells by DCFH-DA assay. Dissipation of mitochondrial membrane potential of intact cells accompanied by increase in cytosolic cytochrome c was observed, which was followed by activation of caspase-9 and -3 but not caspase-8. DNA fragmentation analysis revealed typical ladders as early as 18 h indicative of caspase-3 role in the apoptotic pathway. The overall results suggest that ESB induces mitochondria-mediated intrinsic apoptotic pathway in HL60 cells and might have therapeutic value against human leukemia.