An Insight into the Mechanism of Holamine- and Funtumine-Induced Cell Death in Cancer Cells.

Holamine and funtumine, steroidal alkaloids with strong and diverse pharmacological activities are commonly found in the Apocynaceae family of Holarrhena. The selective anti-proliferative and cell cycle arrest effects of holamine and funtumine on cancer cells have been previously reported. The present study evaluated the anti-proliferative mechanism of action of these two steroidal alkaloids on cancer cell lines (HT-29, MCF-7 and HeLa) by exploring the mitochondrial depolarization effects, reactive oxygen species (ROS) induction, apoptosis, F-actin perturbation, and inhibition of topoisomerase-I. The apoptosis-inducing effects of the compounds were studied by flow cytometry using the APOPercentageTM dye and Caspase-3/7 Glo assay kit. The two compounds showed a significantly greater cytotoxicity in cancer cells compared to non-cancer (normal) fibroblasts. The observed antiproliferative effects of the two alkaloids presumably are facilitated through the stimulation of apoptosis. The apoptotic effect was elicited through the modulation of mitochondrial function, elevated ROS production, and caspase-3/7 activation. Both compounds also induced F-actin disorganization and inhibited topoisomerase-I activity. Although holamine and funtumine appear to have translational potential for the development of novel anticancer agents, further mechanistic and molecular studies are recommended to fully understand their anticancer effects.

Patterns of copy number alterations in primary breast tumors of South African patients and their impact on functional cellular pathways.

Breast cancer is the most common and the leading cause of female mortality among South African (SA) women. Several non­biological and biological risk factors may be attributed to their observed high mortality rate; however, the molecular profiles associated with their breast tumors are poorly characterized. The present study examined the patterns of genome-wide copy number alterations (CNAs) and their potential impact on functional cellular pathways targeted by cancer driver genes in patients with breast cancer from the Western Cape region of SA. Array-comparative genomic hybridization analysis, performed in 28 cases of invasive breast cancer, revealed a mean number of 8.68±6.18 CNAs per case, affecting primarily the Xp22.3 and 6p21-p25 cytobands (57.14% of the cases), followed by 19p13.3-p13.11 (35.7%), 2p25.3-p24.3, 4p16.3-p15.3, 8q11.1-q24.3 and 16 p13.3-p11.2 (32.14%). Functional enrichment analysis of genes and microRNA targets mapped in these affected cytobands revealed critical cancer-associated pathways, including fatty acid biosynthesis and metabolism, extracellular matrix-receptor interaction, hippo and tumor protein p53 signaling pathways, which are regulated by known cancer genes, including CCND1, CDKN1A, MAPK1, MDM2, TP53 and SMAD2. An inverse correlation was observed among the number of CNAs and tumor size and grade; CNAs on the 4p and 6p cytobands were also inversely correlated with tumor grade. No association was observed in the number of CNAs and/or the affected cytobands and the different ethnic groups of the SA patients, indicating that their tumor genome is affected by CNAs, irrespectively of their genetic descent. Additional genomic tumor profiling in SA and other Sub-Saharan African patients with breast cancer is required to determine the associations of the CNAs observed with prognosis and clinical outcome.

Isolation and antioxidant activity of flavonoids from Holarrhena floribunda (G.don) leaves.

Bioactive polyphenolics are ubiquitously present in plants and may play an important role in the prevention and management of certain human diseases. Three known flavonoids viz Kaemperol-3-O-rutinoside (1), quercetin-3-O-glucoside (2) and kaemperol-3-O-glucoside (3) and inseparable mixture (1:1) of quercetin-3-O-glucose/galactose (4) were isolated, and identified for the first time from Holarrhena floribunda. The antioxidant capacity using the ORAC, FRAP and TEAC assays and inhibition of lipid peroxidation were measured for isolated flavonoids. The result showed that compounds 2 and 4 showed significantly increased ORAC, TEAC, and FRAP activities with low pro-oxidant potential as well as improved lipid peroxidation inhibition levels when compared to compounds 1 and 3. The most active compounds were found to be flavonoids with a quercetin basic structure. These results imply that the isolated flavonoid glycosides are responsible for the antioxidant activity of the plant leaves and it forms the scientific basis for its traditional usage.

In Vitro and In Vivo Biochemical Evaluations of the Methanolic Leaf Extract of Garcinia kola.

Garcinia kola Heckel (Guttiferae) leaves have received limited scientific attention despite their traditionally acclaimed medicinal properties. The scavenging ability of the methanolic leaf extract (MLE) of G. kola was assayed for hydroxyl radical (OH(•)), superoxide anion (O2 (-)), 1,1-diphenyl-2-picrylhydrazyl (DPPH), azinobis-3-ethyl-benzothiazoline-6-sulfonic acid (ABTS(•+)), and lipid peroxidation (LP) activity in egg yolk, rat liver, and brain homogenates. Total phenolic and flavonoid contents of the extract were also evaluated. Group I animals were given oral doses of water, whereas Group II and Group III animals received 100 and 200 mg/kg body weight (bw) MLE, respectively, for 14 days. Plasma glucose, magnesium, γ-glutamyltransferase (GGT/γGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, and urea were evaluated. Hepatic reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), LP, and liver histopathological appearance were also assessed. The extract scavenged OH(•), O2 (-), DPPH, and ABTS(•+) and inhibited LP in egg yolk, rat liver, and brain homogenates. Furthermore, oral administration of the extract showed no adverse effects on hepatic and renal function tests. Increased hepatic GSH and nonsignificant changes in LP, GPx and SOD activities, and liver histology were observed. These results suggest that G. kola leaves have antioxidant activities which may have application in traditional medicine.

Evaluation of antioxidant, antimutagenic, and lipid peroxidation inhibitory activities of selected fractions of Holarrhena floribunda (G. Don) leaves.

Exposure to environmental pollutants often leads to an upsurge in the production of reactive oxygen species (ROS). ROS oxidize cellular fatty acids to produce lipid peroxyl radicals, subsequently transformed into lipid peroxides, which decrease membrane fluidity and increase the activity of various enzymes implicated in degenerative diseases and cancer formation. Edible plants that contain exogenous compounds like curcumeroid, ß-carotene, turmeric, and so on, protect the aerobic cells from oxidation of free radicals. This study thus evaluates antioxidant and antimutagenic activities of ethyl acetate, aqueous and methanolic fractions of Holarrhena floribunda leaves. Inhibitory activities of the ethyl acetate fraction on Fe(2+)-induced lipid peroxidation in hen egg yolk; rat liver and brain tissues were also evaluated. The Allium cepa root assay was used to evaluate antimutagenic activity. Results showed that the ethyl acetate scavenged DPPH, OH•, and •O2(-) much stronger than other fractions, as evidenced by its lowest respective IC50 values. All the fractions displayed antimutagenic activities against cyclophosphamide-induced chromosomal aberrations. Likewise, all the fractions induced a reduction in mitotic index, a hallmark of cytotoxicity in the root meristem of Allium cepa. The decrease in mitotic index was most profound for the ethyl acetate fraction, which also demonstrated a significant lipid peroxidation inhibitory activity in the liver and brain homogenates, but not in egg yolk, compared with the ascorbic acid standard. In general, the results suggest that the ethyl acetate fraction might contain beneficial phytochemicals that should be explored as novel candidates for preclinical drug development.

Criteria to facilitate the implementation of woman-centred care in childbirth units of Limpopo Province, South Africa (Part 2).

BACKGROUND: Facilitation of mutual participation, respectful and egalitarian relationship between the mother and the midwife during childbirth is a critical aspect. This article delineated the criteria that would facilitate the implementation of woman-centred care in childbirth units of the Limpopo Province in South Africa, following a concept analysis described in Part 1. Empirical referents or indicators were used to measure the concept woman-centred care and to validate its existence in reality. These empirical referents were referred to as measurable properties that further verified the concept. OBJECTIVE: The objective of this article was to formulate criteria that would facilitate implementation of woman-centred care in childbirth units of Limpopo Province in South Africa. METHOD: Criteria to facilitate the implementation of woman-centred care were formulated by the gathering of information about the topic under review and the use of resources to define the key elements of the criteria which were integrated into the Batho Pele principles. The criteria were then validated by selecting with a vested interest in the successful development and implementation of the criteria. RESULTS: Criteria were formulated to facilitate the implementation of woman-centred care that was integrated within the framework of Batho Pele principles. CONCLUSION: These formulated criteria for woman-centred care will be used as an institutional self-evaluation tool to enhance implementation of the Batho Pele principles in childbirth units. These criteria will give direction and provide guidelines for the performance of midwifery staff and will also help supervisors to guide staff to improve performance.

Optimization and preclinical design of genetically engineered viruses for human oncolytic therapy.

INTRODUCTION: Oncolytic viruses (OVs) occupy a strategic niche in the dynamic era of biological and gene therapy of human cancers. However, the use of OVs is the subject of close scrutiny due to impediments such as the insufficiency of patient generalizations posed by heterogeneous tumor responses to treatment, inherent or potentially lethal viral pathogenicities, unanticipated host- or immune-related adverse effects, and the emergence of virus-resistant cancer cells. These challenges can be overcome by the design and development of more definitive (optimized, targeted, and individualized) cancer virotherapeutics. AREAS COVERED: The translation of current knowledge and recent innovations into rational treatment prospects hinges on an iterative loop of variables pertaining to genetically engineered viral oncolytic efficacy and safety profiles, mechanism-of-action data, potencies of synergistic oncolytic viral combinations with conventional tumor, immuno-, chemo-, and radiation treatment modalities, optimization of the probabilities of treatment successes in heterogeneous (virus-sensitive and -resistant) tumor cell populations by mathematical modeling, and lessons learned from preclinical studies and human clinical trials. EXPERT OPINION: In recent years, it has become increasingly clear that proof-of-principle is critical for the preclinical optimization of oncolytic viruses to target heterogeneous forms of cancer and to prioritize current concerns related to the efficacy and safety of oncolytic virotherapy.

Implications of endoplasmic reticulum stress, the unfolded protein response and apoptosis for molecular cancer therapy. Part II: targeting cell cycle events, caspases, NF-κB and the proteasome.

BACKGROUND: Endoplasmic reticulum stress (ERS), the unfolded protein response (UPR) and apoptosis signal transduction pathways are fundamental to normal cellular homeostasis and survival, but are exploited by cancer cells to promote the cancer phenotype. OBJECTIVE: Collateral activation of ERS and UPR role players impact on cell growth, cell cycle arrest or apoptosis, genomic stability, tumour initiation and progression, tumour aggressiveness and drug resistance. An understanding of these processes affords promising prospects for specific cancer drug targeting of the ERS, UPR and apoptotic pathways. METHOD: This review (Part II of II) brings forward the latest developments relevant to the molecular connections among cell cycle regulators, caspases, NF-κB, and the proteasome with ERS and UPR signalling cascades, their functions in apoptosis induction, apoptosis resistance and oncogenesis, and how these relationships can be exploited for targeted cancer therapy. CONCLUSION: Overall, ERS, the UPR and apoptosis signalling cascades (the molecular therapeutic targets) and the development of drugs that attack these targets signify a success story in cancer drug discovery, but a more reductionist approach is necessary to determine the precise molecular switches that turn on antiapoptotic and pro-apoptotic programmes.

Implications of endoplasmic reticulum stress, the unfolded protein response and apoptosis for molecular cancer therapy. Part I: targeting p53, Mdm2, GADD153/CHOP, GRP78/BiP and heat shock proteins.

BACKGROUND: In eukaryotes, endoplasmic reticulum stress (ERS) and the unfolded protein response (UPR) are coordinately regulated to maintain steady-state levels and activities of various cellular proteins to ensure cell survival. OBJECTIVE: This review (Part I of II) focuses on specific ERS and UPR signalling regulators, their expression in the cancer phenotype and apoptosis, and proposes how their implication in these processes can be rationalised into proteasome inhibition, apoptosis induction and the development of more efficacious targeted molecular cancer therapies. METHOD: In this review, we contextualise many ERS and UPR client proteins that are deregulated or mutated in cancers and show links between ERS and the UPR, their implication in oncogenic transformation, tumour progression and escape from immune surveillance, apoptosis inhibition, angiogenesis, metastasis, acquired drug resistance and poor cancer prognosis. CONCLUSION: Evasion of programmed cell death or apoptosis is a hallmark of cancer that enables tumour cells to proliferate uncontrollably. Successful eradication of cancer cells through targeting ERS- and UPR-associated proteins to induce apoptosis is currently being pursued as a central tenet of anticancer drug discovery.

Combination of tunicamycin with anticancer drugs synergistically enhances their toxicity in multidrug-resistant human ovarian cystadenocarcinoma cells.

BACKGROUND: The pharmacologic modulatory effects of the antibiotic, tunicamycin (TM), on multidrug-resistant human UWOV2 ovarian cancer cells are reported. The UWOV2 cell line was derived from a cystadenocarcinoma in a patient refractory to combination chemotherapy with actinomycin D, vincristine (VCR), cis-diaminedichloroplatinum (II) (CDDP) and doxorubicin (DXR). In an attempt to explain drug resistance in this cell line, we examined the effects of TM on their sensitivity to various anticancer drugs, the uptake, efflux and retention of [3H]VCR, and their ability to bind [14C]DXR and [3H]azidopine (AZD), a photoaffinity label of the multidrug transporter, P-glycoprotein (Pgp). RESULTS: TM effectively decreased the EC50 for DXR, EXR, VCR and CDDP, thus enhancing their cytotoxicity. The antibiotic also prolonged the intracellular retention time of [3H]VCR and increased the binding of both [14C]DXR and [3H]AZD to the cells. CONCLUSION: It is concluded that the pharmacomodulatory effects of TM in these cells are mediated by global inhibition of protein and glycoprotein synthesis and synergistic interaction with antineoplastic drugs. The ability of TM to enhance the sensitivity of drug resistant tumour cells may have impact on the design and optimization of novel resistance modifiers to improve the efficacy of combination treatment of intractable neoplasms.