Effects of Vitellaria paradoxa (C.F. Gaertn.) aqueous leaf extract administration on Salmonella typhimurium-infected rats.

BACKGROUND: The present study investigates the effects of Vitellaria paradoxa crude extract administration on Salmonella typhimurium infected Wistar rats. METHODS: Rats were infected by single dose oral administration of Salmonella typhimurium (1.5×108 CFU). Negative control groups were infected and treated orally with distilled water (vehicle), neutral control group were not infected, while the four test groups were treated up to 18 days with 55 mg/kg, 110 mg/kg, 220 mg/kg and 440 mg/kg body weight of aqueous extract of V. paradoxa respectively. The effects of this extract administration on serum markers (total protein, creatinine, transaminases, bilirubin and lipid profile) as well as acute toxicity test and phytochemical screening were also investigated. RESULTS: Following in vivo studies, aqueous extract of V. paradoxa allowed to clear salmonellosis in previously infected rats within twelve days of treatment. Infection has resulted in a significant increase of transaminases activity. Besides, significant decrease was observed in liver and kidney relative weight and their protein content. Nevertheless, administration of this plant extract at higher doses has resulted in the correction of some of these injuries. Results obtained from acute toxicity study showed that mice administered with the aqueous leaf extract exhibited a mild reaction to noise and pinch; excreted watery discharges and the LD50 value was 12.0 g/kg. In addition, the extract showed no toxic effect after 14 days. However, it may have a sedative effect or depressant effect on the central nervous system, may induce a decrease in plasma levels of algogenic substances, and may cause diarrhea at high doses. Phytochemical screening of the extract revealed the presence of flavonoids, alkaloids, tannins, phenols and polyphenols, saponins, anthocyanins, steroids and anthraquinones. CONCLUSIONS: These results support the ethnomedicinal use of V. paradoxa, and suggest that its leave can be used in the management antibacterial phytomedicine.

Importance of epigenetic changes in cancer etiology, pathogenesis, clinical profiling, and treatment: what can be learned from hematologic malignancies?

Epigenetic alterations represent a key cancer hallmark, even in hematologic malignancies (HMs) or blood cancers, whose clinical features display a high inter-individual variability. Evidence accumulated in recent years indicates that inactivating DNA hypermethylation preferentially targets the subset of polycomb group (PcG) genes that are regulators of developmental processes. Conversely, activating DNA hypomethylation targets oncogenic signaling pathway genes, but outcomes of both events lead in the overexpression of oncogenic signaling pathways that contribute to the stem-like state of cancer cells. On the basis of recent evidence from population-based, clinical and experimental studies, we hypothesize that factors associated with risk for developing a HM, such as metabolic syndrome and chronic inflammation, trigger epigenetic mechanisms to increase the transcriptional expression of oncogenes and activate oncogenic signaling pathways. Among others, signaling pathways associated with such risk factors include pro-inflammatory nuclear factor κB (NF-κB), and mitogenic, growth, and survival Janus kinase (JAK) intracellular non-receptor tyrosine kinase-triggered pathways, which include signaling pathways such as transducer and activator of transcription (STAT), Ras GTPases/mitogen-activated protein kinases (MAPKs)/extracellular signal-related kinases (ERKs), phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR), and ß-catenin pathways. Recent findings on epigenetic mechanisms at work in HMs and their importance in the etiology and pathogenesis of these diseases are herein summarized and discussed. Furthermore, the role of epigenetic processes in the determination of biological identity, the consequences for interindividual variability in disease clinical profile, and the potential of epigenetic drugs in HMs are also considered.

Normal hematopoiesis and hematologic malignancies: role of canonical Wnt signaling pathway and stromal microenvironment.

Wnts are a family of evolutionary-conserved secreted signaling molecules critically involved in a variety of developmental processes and in cell fate determination. A growing body of evidence suggests that Wnt signaling plays a crucial role in the influence of bone marrow stromal microenvironment on the balance between hematopoietic stem cell self-renewal and differentiation. Emerging clinical and experimental evidence also indicates Wnt signaling involvement in the disruption of the latter balance in hematologic malignancies, where the stromal microenvironment favors the homing of cancer cells to the bone marrow, as well as leukemia stem cell development and chemoresistance. In the present review, we summarize and discuss the role of the canonical Wnt signaling pathway in normal hematopoiesis and hematologic malignancies, with regard to recent findings on the stromal microenvironment involvement in these process and diseases.

Role of epigenetic in cancer biology, in hematologic malignancies and in anticancer therapy.

Major epigenetic changes are associated with carcinogenesis, including aberrant DNA methylations and post-translational modifications of histone. Indeed evidence accumulated in recent years indicates that inactivating DNA hypermethylation preferentially targets the subset of polycomb group (PcG) genes that are regulators of developmental processes. Conversely, activating DNA hypomethylation targets oncogenic signaling pathway genes, but outcomes of both events lead in the overexpression of oncogenic signaling pathways that contribute to the stem-like state of cancer cells. On the basis of recent evidence from population-basedclinical and experimental studies, we hypothesize that factors associated with risk for developing a hematologic malignancy (HM), such as metabolic syndrome and chronic inflammation, may trigger epigenetic mechanisms to increase the transcriptional expression of oncogenes and activate oncogenic signaling pathways. Signaling pathways associated with such risk factors include but are not limited to pro-inflammatory nuclear factor κB (NF-κB) and mitogenic, growth, and survival Janus kinase (JAK) intracellular non-receptor tyrosine kinase-triggered pathways. The latter includes signaling pathways such as transducer and activator of transcription (STAT), Ras GTPases/mitogen-activated protein kinases (MAPKs)/extracellular signal-related kinases (ERKs), phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR), and ß-catenin pathways. Recent findings on epigenetic mechanisms at work in the biology of cancer and in HMs and their importance in the etiology and pathogenesis of these diseases are herein summarized and discussed. Furthermore, the role of epigenetic processes in the determination of biological identity, the consequences for interindividual variability in disease clinical profile, and the potential of epigenetic drugs in HMs are also considered.

Assessment of breast cancer awareness and detection of asymptomatic cases in Ngaoundere, Adamawa region of Cameroon.

Introduction: In Cameroon and most African countries, breast cancer (BC) is mainly diagnosed at an advanced stage, leading to worse prognosis and disease consequences. This is partly due to the delayed presentation of patients, which constitutes a significant barrier to the effective management of the disease. The aim of this descriptive, cross-sectional study is to identify the level of awareness of breast cancer and screening practice among women and health professionals in the city of Ngaoundere, Cameroon. Methods: Women and medical personnel were randomly recruited in two health institutions in the Adamawa region, Cameroon: the Ngaoundere Regional Hospital and the Ngaoundere Protestant Hospital. Two different questionnaires were prepared. The first was to collect sociodemographic data and assess participants' awareness of BC and related symptoms. The second was to collect information from the recommended screening methods for early detection of cases, including the frequency of screening practice among women and the daily practice of medical personnel. Results: Out of the women surveyed, 88.05 % have heard of breast cancer, but the majority were unaware of its clinical signs (47.1 %) and the means of treatment (22 %). In the studied population, 66.4 % were aware of the screening, but the practice was very low, as only 1.1 % of women had ever undergone screening by mammography and only 6 % often practiced breast self-examination (BSE). The levels of screening knowledge and practice were significantly associated with the level of education and employment status (P = 0.0001). In the group of 94 health personnel surveyed, 68.1 % had no knowledge of breast cancer screening methods, and only 30 % performed breast cancer screening in their daily practice. The practice of BSE during the study allowed a detection of 2 % of screened women with some suspicious clinical signs. Conclusion: This study revealed a lack of knowledge about BC and its screening methods and practice among women and health personnel in Ngaoundere. This lack of knowledge constitutes a significant barrier to early diagnosis of BC. There is a need to raise awareness and provide education and information about BC screening.

Notch signaling in acute lymphoblastic leukemia: any role for stromal microenvironment?

Notch signaling pathway regulates many different events of embryonic and adult development; among them, Notch plays an essential role in the onset of hematopoietic stem cells and influences multiple maturation steps of developing lymphoid and myeloid cells. Deregulation of Notch signaling determines several human disorders, including cancer. In the last decade it became evident that Notch signaling plays pivotal roles in the onset and development of T- and B-cell acute lymphoblastic leukemia by regulating the intracellular molecular pathways involved in leukemia cell survival and proliferation. On the other hand, bone marrow stromal cells are equally necessary for leukemia cell survival by preventing blast cell apoptosis and favoring their reciprocal interactions and cross-talk with bone marrow microenvironment. Quite surprisingly, the link between Notch signaling pathway and bone marrow stromal cells in acute lymphoblastic leukemia has been pointed out only recently. In fact, bone marrow stromal cells express Notch receptors and ligands, through which they can interact with and influence normal and leukemia T- and B-cell survival. Here, the data concerning the development of T- and B-cell acute lymphoblastic leukemia has been critically reviewed in light of the most recent findings on Notch signaling in stromal microenvironment.

Notch-3 and Notch-4 signaling rescue from apoptosis human B-ALL cells in contact with human bone marrow-derived mesenchymal stromal cells.

Although many literature data are available on the role of Notch signaling in T-cell acute lymphoblastic leukemia (ALL) biology, the importance of this molecular pathway in the development of B-lineage ALL (B-ALL) cells in the BM microenvironment is unknown so far. In this study, we used anti-Notch molecules neutralizing Abs and γ-secretase inhibitor (GSI) XII to investigate the role of the Notch signaling pathway in the promotion of human B-ALL cell survival in presence of stromal cell support. The treatment with combinations of anti-Notch molecule neutralizing Abs resulted in the decrease of B-ALL cell survival, either cultured alone or cocultured in presence of stromal cells from normal donors and B-ALL patients. Interestingly, the inhibition of Notch-3 and -4 or Jagged-1/-2 and DLL-1 resulted in a dramatic increase of apoptotic B-ALL cells by 3 days, similar to what is obtained by blocking all Notch signaling with the GSI XII. Our data suggest that the stromal cell-mediated antiapoptotic effect on B- ALL cells is mediated by Notch-3 and -4 or Jagged-1/-2 and DLL-1 in a synergistic manner.

Cervical Precancerous Lesions and Associated Factors Among Women Screened in Two Hospitals in the City of Douala, Cameroon.

INTRODUCTION: Cervical cancer remains the second leading cause of death among women in Cameroon despite the new strategies put in place. This study was conducted in order to determine the prevalence of precancerous cervical lesions and its associated factors in Douala (Cameroon). METHODS:  A cross-sectional study was conducted over a period of nine months in two hospitals of the city of Douala, Cameroon (Laquintinie Hospital and Gyneco-Ostetric and Pediatric Hospital). Cervico-vaginal and endocervical samples were taken from women attending the above-mentioned hospitals in order to identify and characterize precancerous lesions by cytological examination and to genotype for human papillomavirus (HPV) using the Abbott RealTime High-Risk (HR) HPV kit. Data of sociodemographic characteristics, clinical history, and knowledge about cervical cancer were collected using a questionnaire. RESULTS: Of the 196 women included in this study, 17% had precancerous lesions, including 1.53% for atypical glandular cells (AGC), 4.53% for atypical squamous cells (ASC), 4.53% for low-grade squamous intraepithelial lesion (LSIL), 5.61% for high-grade squamous intraepithelial lesion (HSIL), 0.51% for atypical squamous cells of undetermined significance (ASC-US), and 0.51% for atypical squamous cells cannot exclude HSIL (ASC-H). In addition, the prevalence of HPV infection was 18%, of which 2% was for HPV 16, 2% for HPV 18, and 14% for undetermined HPV. A positive association was recorded between the occurrence of precancerous lesions and HPV infection (P=0.01), age, and school level. Moreover, the occurrence of precancerous lesions was positively associated with the participants' level of knowledge (P=0.01). DISCUSSION: Precancerous lesions were predominantly HSIL, and the factor most associated with these lesions was HPV infection. CONCLUSION: This study demonstrates that diagnosis is made at a relatively late stage due to a low level of knowledge about cervical cancer in the population.

A new flavonoid glycoside from Tapinanthus sp. (Loranthaceae) and evaluation of anticancer activity of extract and some isolated compounds.

The present work describes the isolation and anticancer activity of Tapinanthus sp. which is a hemi parasitic plant harvested on Combretum glutinosum, the host plant. Phytochemical study afforded a new flavonoid glycoside, tapinantoside (1) isolated for the first time from natural source, alongside six known compounds (2-7). Structure of compounds were elucidated by extensive spectroscopic analyses including 1 D and 2 D NMR, mass spectrometry and by comparison with literature data. The anticancer activity of extract and some isolated compounds were evaluated on glioblastoma (U87MG, C6) and prostate (PC-3) cancer cells. The methanol leaves extract showed good anticancer activity against U87 (IC50 = 21.40 µg/mL) and PC-3 cells (IC50 = 10.26 µg/mL). Compound 3 powerfully inhibits the proliferation of C6 (IC50 = 38.84 µM) and PC-3 cells (IC50 = 21.33 µM), while its effect was moderated on U87MG cells. Compound 1 and 7 were not active on all tested cancer cell lines.

Awareness of Breast Cancer Screening among the Medical and General Population of the North Region of Cameroon.

Breast cancer has become a real public health problem in Cameroon, particularly in rural areas due to late diagnosis, resulting partly from the absence of national screening programs. This work is aimed at assessing breast cancer awareness in the North Region of Cameroon. Participants were selected in six health centers surrounding the rural area of Garoua, North Region, Cameroon, and administered a questionnaire aimed at assessing their awareness about breast cancer risk factors and screening. Out of the 475 women (including 37 medical personnel) interviewed, 45.5% attended at least secondary school; 91.3% were aware of the disease with the main sources of information from those around them (64.8%), media (46.5%), and health professionals in health facilities (42.7%). 23.3% had misconceptions and myth-based ideas on the origin of the disease. Ignorance was the main reason preventing the performance of breast self-examination, and the high cost prevents individuals from going for mammography. The highest awareness rate was observed in employed women with higher level of education. Our study highlights the need to raise awareness among the populations in North Region, Cameroon, about the risk factors and clinical signs of breast cancer and the importance of screening practice for early diagnosis of breast cancer.

Breast cancer awareness and screening practice amongst health personnel and general population of the littoral region of Cameroon.

Introduction: Late diagnosis has been observed as the hallmark of breast cancer in Cameroonian women where over 70% of patients report with either stage III or IV of the disease, with high mortality and dire socioeconomic consequences. The present study was undertaken to assess the awareness of breast cancer, warning signs and screening methods among Health professionals and general population of Douala. Methods: Participants included in this study were health practitioners and women randomly selected and enrolled in six health facilities in the city of Douala, Littoral Region, Cameroon. A self-administered questionnaire was designed for each group and aimed at assessing their knowledge about breast cancer, warning signs and screening practices. Then, 616 women underwent breast palpation, followed by fine needle aspiration (FNA) when a nodule was found. Results: Out of a total of 737 participants (121 health personnel and 616 women) interviewed, a majority (96.3%) were aware of the disease with the main source of information being the hospital (76.0%), media (47.1%) and vocational training schools (45.4%) for health personnel; medias (39.9%), health professionals (26.1%) and their entourage (21.9%) for the population. Health workforce presented suitable awareness of the risk factors for breast cancer and its clinical signs even though 37.1% of them had misconceptions and myth-based ideas on the origin of the disease. Both the population and health personnel were aware of the possibility of early screening for breast cancer and cited breast self-examination, clinical breast examination and mammography as screening techniques. Nonetheless, screening practice amongst all women is very poor and mainly due to ignorance, high cost of mammography, together with a lack of mastery of the BSE technique and the fear of actually discovering signs of the disease. Conclusion: Our findings show lack of awareness and low practice of breast cancer screening amongst women in Douala and highlight the need to raise awareness and provide the right information to the public for early detection of breast cancer.

Methylation Dynamics of RASSF1A and Its Impact on Cancer.

5-methyl cytosine (5mC) is a key epigenetic mark entwined with gene expression and the specification of cellular phenotypes. Its distribution around gene promoters sets a barrier for transcriptional enhancers or inhibitor proteins binding to their target sequences. As a result, an additional level of regulation is added to the signals that organize the access to the chromatin and its structural components. The tumor suppressor gene RASSF1A is a microtubule-associated and multitasking scaffold protein communicating with the RAS pathway, estrogen receptor signaling, and Hippo pathway. RASSF1A action stimulates mitotic arrest, DNA repair and apoptosis, and controls the cell cycle and cell migration. De novo methylation of the RASSF1A promoter has received much attention due to its increased frequency in most cancer types. RASSF1A methylation is preceded by histones modifications and could represent an early molecular event in cell transformation. Accordingly, RASSF1A methylation is proposed as an epigenetic candidate marker in many cancer types, even though an inverse correlation of methylation and expression remains to be fully ascertained. Some findings indicate that the epigenetic abrogation of RASSF1A can promote the alternative expression of the putative oncogenic isoform RASSF1C. Understanding the complexity and significance of RASSF1A methylation is instrumental for a more accurate determination of its biological and clinical role. The review covers the molecular events implicated in RASSF1A methylation and gene silencing and provides a deeper view into the significance of the RASSF1A methylation patterns in a number of gastrointestinal cancer types.

Developmental pathways associated with cancer metastasis: Notch, Wnt, and Hedgehog.

Master developmental pathways, such as Notch, Wnt, and Hedgehog, are signaling systems that control proliferation, cell death, motility, migration, and stemness. These systems are not only commonly activated in many solid tumors, where they drive or contribute to cancer initiation, but also in primary and metastatic tumor development. The reactivation of developmental pathways in cancer stroma favors the development of cancer stem cells and allows their maintenance, indicating these signaling pathways as particularly attractive targets for efficient anticancer therapies, especially in advanced primary tumors and metastatic cancers. Metastasis is the worst feature of cancer development. This feature results from a cascade of events emerging from the hijacking of epithelial-mesenchymal transition, angiogenesis, migration, and invasion by transforming cells and is associated with poor survival, drug resistance, and tumor relapse. In the present review, we summarize and discuss experimental data suggesting pivotal roles for developmental pathways in cancer development and metastasis, considering the therapeutic potential. Emerging targeted antimetastatic therapies based on Notch, Wnt, and Hedgehog pathways are also discussed.

Mesenchymal stromal cells' role in tumor microenvironment: involvement of signaling pathways.

Mesenchymal stromal cells (MSCs) are adult multipotent stem cells residing as pericytes in various tissues and organs where they can differentiate into specialized cells to replace dying cells and damaged tissues. These cells are commonly found at injury sites and in tumors that are known to behave like " wounds that do not heal." In this article, we discuss the mechanisms of MSCs in migrating, homing, and repairing injured tissues. We also review a number of reports showing that tumor microenvironment triggers plasticity mechanisms in MSCs to induce malignant neoplastic tissue formation, maintenance, and chemoresistance, as well as tumor growth. The antitumor properties and therapeutic potential of MSCs are also discussed.

Notch signalling drives bone marrow stromal cell-mediated chemoresistance in acute myeloid leukemia.

Both preclinical and clinical investigations suggest that Notch signalling is critical for the development of many cancers and for their response to chemotherapy. We previously showed that Notch inhibition abrogates stromal-induced chemoresistance in lymphoid neoplasms. However, the role of Notch in acute myeloid leukemia (AML) and its contribution to the crosstalk between leukemia cells and bone marrow stromal cells remain controversial. Thus, we evaluated the role of the Notch pathway in the proliferation, survival and chemoresistance of AML cells in co-culture with bone marrow mesenchymal stromal cells expanded from both healthy donors (hBM-MSCs) and AML patients (hBM-MSCs*). As compared to hBM-MSCs, hBM-MSCs* showed higher level of Notch1, Jagged1 as well as the main Notch target gene HES1. Notably, hBM-MSCs* induced expression and activation of Notch signalling in AML cells, supporting AML proliferation and being more efficientin inducing AML chemoresistance than hBM-MSCs*. Pharmacological inhibition of Notch using combinations of Notch receptor-blocking antibodies or gamma-secretase inhibitors (GSIs), in presence of chemotherapeutic agents, significant lowered the supportive effect of hBM-MSCs and hBM-MSCs* towards AML cells, by activating apoptotic cascade and reducing protein level of STAT3, AKT and NF-κB.These results suggest that Notch signalling inhibition, by overcoming the stromal-mediated promotion of chemoresistance,may represent a potential therapeutic targetnot only for lymphoid neoplasms, but also for AML.

Newtonoate as an active principle of Newtonia griffoniana for anxiolytic activity in Swiss mice.

BACKGROUND: Newtonia griffoniana (Mimosaceae) is a Central African rain forest tree, whose bark extracts are used in Cameroonian folk medicine for the treatment of anxiety and sleep disorders. METHODS: We evaluated the anxiolytic effects of N. griffoniana stem bark methanol extract and its major isolated constituent 2,3,4-trihydroxybutylpentatriacontanoate (newtonoate) on the elevated plus maze. RESULTS: Significant increases in the percentage of entries into open arms were induced by both N. griffoniana extract (100 and 150 mg/kg BW; p<0.01) and newtonoate (doses of 3 and 15 mg/kg BW; p<0.05). Conversely, decreases in the percentage of entries into closed arms were observed at the same doses. In addition, N. griffoniana methanol extract (100 mg/kg) and the isolated newtonoate (30 mg/kg) induced significant (p<0.01 and p<0.05, respectively) increases in the time spent in the open arms, while inducing a decrease in the time spent in the closed arms. Newtonoate treatment also decreased head dipping number at doses of 3 and 15 mg/kg, while N. griffoniana methanol extract induced the same effect at 200 mg/kg. CONCLUSIONS: These results suggest that N. griffoniana bark extract has anxiolytic properties, which justify its use in folk medicine. Such effects are at least partly mediated by newtonoate.

New targeted therapies for breast cancer: A focus on tumor microenvironmental signals and chemoresistant breast cancers.

Breast cancer is the most frequent female malignancy worldwide. Current strategies in breast cancer therapy, including classical chemotherapy, hormone therapy, and targeted therapies, are usually associated with chemoresistance and serious adverse effects. Advances in our understanding of changes affecting the interactome in advanced and chemoresistant breast tumors have provided novel therapeutic targets, including, cyclin dependent kinases, mammalian target of rapamycin, Notch, Wnt and Shh. Inhibitors of these molecules recently entered clinical trials in mono- and combination therapy in metastatic and chemo-resistant breast cancers. Anticancer epigenetic drugs, mainly histone deacetylase inhibitors and DNA methyltransferase inhibitors, also entered clinical trials. Because of the complexity and heterogeneity of breast cancer, the future in therapy lies in the application of individualized tailored regimens. Emerging therapeutic targets and the implications for personalized-based therapy development in breast cancer are herein discussed.

Signaling pathways in breast cancer: therapeutic targeting of the microenvironment.

Breast cancer is the most common cancer in women worldwide. Understanding the biology of this malignant disease is a prerequisite for selecting an appropriate treatment. Cell cycle alterations are seen in many cancers, including breast cancer. Newly popular targeted agents in breast cancer include cyclin dependent kinase inhibitors (CDKIs) which are agents inhibiting the function of cyclin dependent kinases (CDKs) and agents targeting proto-oncogenic signaling pathways like Notch, Wnt, and SHH (Sonic hedgehog). CDKIs are categorized as selective and non-selective inhibitors of CDK. CDKIs have been tried as monotherapy and combination therapy. The CDKI Palbocyclib is now a promising therapeutic in breast cancer. This drug recently entered phase III trial for estrogen receptor (ER) positive breast cancer after showing encouraging results in progression free survival in a phase II trials. The tumor microenvironment is now recognized as a significant factor in cancer treatment response. The tumor microenvironment is increasingly considered as a target for combination therapy of breast cancer. Recent findings in the signaling pathways in breast cancer are herein summarized and discussed. Furthermore, the therapeutic targeting of the microenvironment in breast cancer is also considered.

Signaling pathways bridging fate determination of neural crest cells to glial lineages in the developing peripheral nervous system.

Fate determination of neural crest cells is an essential step for the development of different crest cell derivatives. Peripheral glia development is marked by the choice of the neural crest cells to differentiate along glial lineages. The molecular mechanism underlying fate acquisition is poorly understood. However, recent advances have identified different transcription factors and genes required for the complex instructive signaling process that comprise both local environmental and cell intrinsic cues. Among others, at least the roles of Sox10, Notch, and neuregulin 1 have been documented in both in vivo and in vitro models. Cooperative interactions of such factors appear to be necessary for the switch from multipotent neural crest cells to glial lineage precursors in the peripheral nervous system. This review summarizes recent advances in the understanding of fate determination of neural crest cells into different glia subtypes, together with the potential implications in regenerative medicine.