107 research outputs found
Novel Combination of Sorafenib and Celecoxib Provides Synergistic Anti-Proliferative and Pro-Apoptotic Effects in Human Liver Cancer Cells
Molecular targeted therapy has shown promise as a treatment for advanced hepatocellular carcinoma (HCC). Sorafenib, a multikinase inhibitor, recently received FDA approval for the treatment of advanced HCC. However, although sorafenib is well tolerated, concern for its safety has been expressed. Celecoxib (CelebrexĂÂź) is a selective cyclooxygenase-2 (COX-2) inhibitor which exhibits antitumor effects in human HCC cells. The present study examined the interaction between celecoxib and sorafenib in two human liver tumor cell lines HepG2 and Huh7. Our data showed that each inhibitor alone reduced cell growth and the combination of celecoxib with sorafenib synergistically inhibited cell growth and increased apoptosis. To better understand the molecular mechanisms underlying the synergistic antitumor activity of the combination, we investigated the expression profile of the combination-treated liver cancer cell lines using microarray analysis. Combination treatment significantly altered expression levels of 1,986 and 2,483 transcripts in HepG2 and Huh7 cells, respectively. Genes functionally involved in cell death, signal transduction and regulation of transcription were predominantly up-regulated, while genes implicated in metabolism, cell-cycle control and DNA replication and repair were mainly down-regulated upon treatment. However, combination-treated HCC cell lines displayed specificity in the expression and activity of crucial factors involved in hepatocarcinogenesis. The altered expression of some of these genes was confirmed by semi-quantitative and quantitative RT-PCR and by Western blotting. Many novel genes emerged from our transcriptomic analyses, and further functional analyses may determine whether these genes can serve as potential molecular targets for more effective anti-HCC strategies
Role of survivin and its splice variants in tumorigenesis
Survivin, a unique member of the inhibitor of apoptosis (IAP) protein family, is highly expressed in cancer but is undetectable in nonproliferating normal adult tissues, suggesting a potential role in tumorigenesis. Differential splicing of survivin pre-mRNA results in three new survivin variants, survivin-ÎEx3, survivin-2B, and survivin-3B. Loss of survivin-2B expression was found in the later stage of cancer development, while survivin and survivin-ÎEx3 are not, suggesting a differential role of them in tumour development. In this minireview, the author intends to summarise and discuss the current data relevant to the role of survivin and its splicing variants in tumorigenesis, which may facilitate further investigation in this interesting area
Intrinsically determined cell death of developing cortical interneurons
Cortical inhibitory circuits are formed by GABAergic interneurons, a cell population that originates far from the cerebral cortex in the embryonic ventral forebrain. Given their distant developmental origins, it is intriguing how the number of cortical interneurons is ultimately determined. One possibility, suggested by the neurotrophic hypothesis1-5, is that cortical interneurons are overproduced, and then following their migration into cortex, excess interneurons are eliminated through a competition for extrinsically derived trophic signals. Here we have characterized the developmental cell death of mouse cortical interneurons in vivo, in vitro, and following transplantation. We found that 40% of developing cortical interneurons were eliminated through Bax- (Bcl-2 associated X-) dependent apoptosis during postnatal life. When cultured in vitro or transplanted into the cortex, interneuron precursors died at a cellular age similar to that at which endogenous interneurons died during normal development. Remarkably, over transplant sizes that varied 200-fold, a constant fraction of the transplanted population underwent cell death. The death of transplanted neurons was not affected by the cell-autonomous disruption of TrkB (tropomyosin kinase receptor B), the main neurotrophin receptor expressed by central nervous system (CNS) neurons6-8. Transplantation expanded the cortical interneuron population by up to 35%, but the frequency of inhibitory synaptic events did not scale with the number of transplanted interneurons. Together, our findings indicate that interneuron cell death is intrinsically determined, either cell-autonomously, or through a population-autonomous competition for survival signals derived from other interneurons
The inhibition of FGF receptor 1 activity mediates sorafenib-induced antiproliferative effects in human mesothelioma tumor-initiating cells
Tumor-initiating cells (TICs), the subset of cells within tumors endowed with stem-like features, being highly resistant to conventional cytotoxic drugs, are the major cause of tumor relapse. The identification of molecules able to target TICs remains a significant challenge in cancer therapy. Using TIC-enriched cultures (MM1, MM3 and MM4), from 3 human malignant pleural mesotheliomas (MPM), we tested the effects of sorafenib on cell survival and the intracellular mechanisms involved. Sorafenib inhibited cell-cycle progression in all the TIC cultures, but only in MM3 and MM4 cells this effect was associated with induction of apoptosis via the down-regulation of Mcl-1. Although sorafenib inhibits the activity of several tyrosine kinases, its effects are mainly ascribed to Raf inhibition. To investigate the mechanisms of sorafenib-mediated antiproliferative activity, TICs were treated with EGF or bFGF causing, in MM3 and MM4 cells, MEK, ERK1/2, Akt and STAT3 phosphorylation. These effects were significantly reduced by sorafenib in bFGF-treated cells, while a slight inhibition occurred after EGF stimulation, suggesting that sorafenib effects are mainly due to FGFR inhibition. Indeed, FGFR1 phosphorylation was inhibited by sorafenib.
A different picture was observed in MM1 cells, which, releasing high levels of bFGF, showed an autocrine activation of FGFR1 and a constitutive phosphorylation/activation of MEK-ERK1/2. A powerful inhibitory response to sorafenib was observed in these cells, indirectly confirming the central role of sorafenib as FGFR inhibitor.
These results suggest that bFGF signaling may impact antiproliferative response to sorafenib of MPM TICs, which is mainly mediated by a direct FGFR targeting
Role of Stem Cells in Human Uterine Leiomyoma Growth
Uterine leiomyoma is the most common benign tumor in reproductive-age women. Each leiomyoma is thought to be a benign monoclonal tumor arising from a single transformed myometrial smooth muscle cell; however, it is not known what leiomyoma cell type is responsible for tumor growth. Thus, we tested the hypothesis that a distinct stem/reservoir cell-enriched population, designated as the leiomyoma-derived side population (LMSP), is responsible for cell proliferation and tumor growth.LMSP comprised approximately 1% of all leiomyoma and 2% of all myometrium-derived cells. All LMSP and leiomyoma-derived main population (LMMP) but none of the side or main population cells isolated from adjacent myometrium carried a mediator complex subunit 12 mutation, a genetic marker of neoplastic transformation. Messenger RNA levels for estrogen receptor-α, progesterone receptor and smooth muscle cell markers were barely detectable and significantly lower in the LMSP compared with the LMMP. LMSP alone did not attach or survive in monolayer culture in the presence or absence of estradiol and progestin, whereas LMMP readily grew under these conditions. LMSP did attach and survive when directly mixed with unsorted myometrial cells in monolayer culture. After resorting and reculturing, LMSP gained full potential of proliferation. Intriguingly, xenografts comprised of LMSP and unsorted myometrial smooth muscle cells grew into relatively large tumors (3.67 ± 1.07 mm(3)), whereas xenografts comprised of LMMP and unsorted myometrial smooth muscle cells produced smaller tumors (0.54 ± 0.20 mm(3), p<0.05, n = 10 paired patient samples). LMSP xenografts displayed significantly higher proliferative activity compared with LMMP xenografts (p<0.05).Our data suggest that LMSP, which have stem/reservoir cell characteristics, are necessary for in vivo growth of leiomyoma xenograft tumors. Lower estrogen and progesterone receptor levels in LMSP suggests an indirect paracrine effect of steroid hormones on stem cells via the mature neighboring cells
Negative regulation of signal transducer and activator of transcription-3 signalling cascade by lupeol inhibits growth and induces apoptosis in hepatocellular carcinoma cells
Background: Constitutive activation of signal transducer and activator of transcription signalling 3 (STAT3) has been linked with survival, proliferation and angiogenesis in a wide variety of malignancies including hepatocellular carcinoma (HCC). Methods: We evaluated the effect of lupeol on STAT3 signalling cascade and its regulated functional responses in HCC cells. Results: Lupeol suppressed constitutive activation of STAT3 phosphorylation at tyrosine 705 residue effectively in a dose- and time-dependent manner. The phosphorylation of Janus-activated kinases (JAKs) 1 and 2 and Src was also suppressed by lupeol. Pervanadate treatment reversed the downregulation of phospho-STAT3 induced by lupeol, thereby indicating the involvement of a phosphatase. Indeed, we observed that treatment with lupeol increased the protein and mRNA levels of SHP-2, and silencing of SHP-2 abolished the inhibitory effects of lupeol on STAT3 activation. Treatment with lupeol also downregulated the expression of diverse STAT3-regulated genes and decreased the binding of STAT3 to VEGF promoter. Moreover, the proliferation of various HCC cells was significantly suppressed by lupeol, being associated with substantial induction of apoptosis. Depletion of SHP-2 reversed the observed antiproliferative and pro-apoptotic effects of lupeol. Conclusions: Lupeol exhibited its potential anticancer effects in HCC through the downregulation of STAT3-induced pro-survival signalling cascade
CCN3 modulates bone turnover and is a novel regulator of skeletal metastasis
The CCN family of proteins is composed of six secreted proteins (CCN1-6), which are grouped together based on their structural similarity. These matricellular proteins are involved in a large spectrum of biological processes, ranging from development to disease. In this review, we focus on CCN3, a founding member of this family, and its role in regulating cells within the bone microenvironment. CCN3 impairs normal osteoblast differentiation through multiple mechanisms, which include the neutralization of pro-osteoblastogenic stimuli such as BMP and Wnt family signals or the activation of pathways that suppress osteoblastogenesis, such as Notch. In contrast, CCN3 is known to promote chondrocyte differentiation. Given these functions, it is not surprising that CCN3 has been implicated in the progression of primary bone cancers such as osteosarcoma, Ewingâs sarcoma and chondrosarcoma. More recently, emerging evidence suggests that CCN3 may also influence the ability of metastatic cancers to colonize and grow in bone
Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic
This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic
Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study
Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28â2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65â3·22], p\textless0·0001), American Society of Anesthesiologists grades 3â5 versus grades 1â2 (2·35 [1·57â3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01â2·39], p=0·046), emergency versus elective surgery (1·67 [1·06â2·63], p=0·026), and major versus minor surgery (1·52 [1·01â2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research
Regulation of endometrial regeneration; mechanisms contributing to repair and restoration of tissue integrity following menses
The human endometrium is a dynamic, multi-cellular tissue that lines the inside of the
uterine cavity. During a womanâs reproductive lifespan the endometrium is subjected to
cyclical episodes of proliferation, angiogenesis, differentiation/decidualisation, shedding
(menstruation), repair and regeneration in response to fluctuating levels of oestrogen and
progesterone secreted by the ovaries. The endometrium displays unparalleled, tightly
regulated, tissue remodelling resulting in a healed, scar-free tissue following menses or
parturition. Mechanisms responsible for initiation of menses have been well documented:
following progesterone withdrawal there is an increase in inflammatory mediators, focal
hypoxia and induction and activation of matrix-degrading enzymes. In contrast, the
molecular and cellular changes responsible for rapid, regulated, tissue repair at a time when
oestrogen and progesterone are low are poorly understood.
Histological studies using human menstrual phase endometrium have revealed that tissue
destruction and shedding occur in close proximity to re-epithelialisation/repair. It has been
proposed that re-epithelialisation involves proliferation of glandular epithelial cells in the
remaining basal compartment; there is also evidence for a contribution from the underlying
stroma. A role for androgens in the regulation of apoptosis of endometrial stromal cells has
been proposed but the impact of androgens on tissue repair has not been investigated. Studies
using human xenografts and primates have been used to model some aspects of the impact of
progesterone withdrawal but simultaneous shedding (menses) and repair have not been
modelled in mice; the species of choice for translational biomedical research.
In the course of the studies described in this thesis, the following aims have been addressed:
1. To establish a model of menses in the mouse which mimics menses in women,
namely; simultaneous breakdown and repair, overt menstruation, immune cell
influx, tissue necrosis and re-epithelialisation.
2. To use this model to determine if the stromal cell compartment contributes to
endometrial repair.
3. To examine the impact of androgens on the regulation of menses (shedding) and
repair.
An informative mouse model of endometrial breakdown that was characterised by overt
menses, as well as rapid repair, was developed. Immunohistological evidence for extensive
tissue remodelling including active angiogenesis, transient hypoxia, epithelial cell-specific
proliferation and re-epithelialisation were obtained by examining uterine tissues recovered
during an âearly window of breakdown and repairâ (4 to 24 hours after progesterone
withdrawal). Novel data included identification of stromal cells that expressed epithelial cell
markers, close to the luminal surface following endometrial shedding, suggesting a role for
mesenchymal to epithelial transition (MET) in re-epithelialisation of the endometrium. In
support of this idea, array and qRTPCR analyses revealed dynamic changes in expression of
mRNAs encoded by genes known to be involved in MET during the window of breakdown
and repair. Roles for hypoxia and tissue-resident macrophages in breakdown and tissue
remodelling were identified.
Treatment of mice with dihydrotestosterone to mimic concentrations of androgens circulated
in women at the time of menses had an impact on the timing and duration of endometrial
breakdown. Array analysis revealed altered expression of genes implicated in MET and
angiogenesis/inflammation highlighting a potential, previously unrecognised role for
androgens in regulation of tissue turnover during menstruation.
In summary, using a newly refined mouse model new insights were obtained, implicating
androgens and stromal MET in restoration of endometrial tissue homeostasis during
menstruation. These findings may inform development of new treatments for disorders
associated with aberrant repair such as heavy menstrual bleeding and endometriosis
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