Identification Of Growth Factors Research Articles

Identification of Growth Factors, Cytokines and Mediators Regulated by Artemisia annua L. Polyphenols (pKAL) in HCT116 Colorectal Cancer Cells: TGF-β1 and NGF-β Attenuate pKAL-Induced Anticancer Effects via NF-κB p65 Upregulation.

The anticancer effects of natural phytochemicals are relevant to the modulation of cytokine signaling pathways in various cancer cells with stem-like properties as well as immune cells. The aim of this study was to elucidate a novel anticancer mechanism of Artemisia annua L. polyphenols (pKAL) involved in the regulation of growth factors, cytokines and mediators in stem-like HCT116 colorectal cancer cells. Through RayBiotech human L-1000 antibody array and bioinformatics analysis, we show here that pKAL-induced anticancer effects are associated with downregulation of growth factor and cytokine signaling proteins including TGFA, FGF16, PDGFC, CCL28, CXCR3, IRF6 and SMAD1. Notably, we found that TGF-β signaling proteins such as GDF10, ENG and TGFBR2 and well-known survival proteins such as NGF-β, VEGFD and insulin were significantly upregulated by pKAL. Moreover, the results of hematoxylin staining, cell viability assay and Western blot analysis demonstrated that TGF-β1 and NGF-β attenuated pKAL-induced anticancer effects by inhibiting pKAL-induced downregulation of caspase-8, NF-κB p65 and cyclin D1. These results suggest that certain survival mediators may be activated by pKAL through the TGF-β1 and NGF-β signaling pathways during pKAL-induced cell death and thus, strategies to inhibit the survival signaling are inevitably required for more effective anticancer effects of pKAL.

Decreased plasma concentrations of BDNF and IGF-1 in abstinent patients with alcohol use disorders.

The identification of growth factors as potential biomarkers in alcohol addiction may help to understand underlying mechanisms associated with the pathogenesis of alcohol use disorders (AUDs). Previous studies have linked growth factors to neural plasticity in neurocognitive impairment and mental disorders. In order to further clarify the impact of chronic alcohol consumption on circulating growth factors, a cross-sectional study was performed in abstinent AUD patients (alcohol group, N = 91) and healthy control subjects (control group, N = 55) to examine plasma concentrations of brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1) and IGF-1 binding protein-3 (IGFBP-3). The association of these plasma peptides with relevant AUD-related variables and psychiatric comorbidity was explored. The alcohol group was diagnosed with severe AUD and showed an average of 13 years of problematic use and 10 months of abstinence at the moment of participating in the study. Regarding common medical conditions associated with AUD, we observed an elevated incidence of alcohol-induced liver and pancreas diseases (18.7%) and psychiatric comorbidity (76.9%). Thus, AUD patients displayed a high prevalence of dual diagnosis (39.3%) [mainly depression (19.9%)] and comorbid substance use disorders (40.7%). Plasma BDNF and IGF-1 concentrations were significantly lower in the alcohol group than in the control group (p<0.001). Remarkably, there was a negative association between IGF-1 concentrations and age in the control group (r = -0.52, p<0.001) that was not found in the alcohol group. Concerning AUD-related variables, AUD patients with liver and pancreas diseases showed even lower concentrations of BDNF (p<0.05). In contrast, the changes in plasma concentrations of these peptides were not associated with abstinence, problematic use, AUD severity or lifetime psychiatric comorbidity. These results suggest that further research is necessary to elucidate the role of BDNF in alcohol-induced toxicity and the biological significance of the lack of correlation between age and plasma IGF-1 levels in abstinent AUD patients.

Advances in the treatment of rotator cuff lesions by cytokines.

Rotator cuff tears are one of the most common shoulder problems that usually require operative treatments. Therapeutic options used to repair ruptured tendons have consisted of suture, autografts, allografts, and synthetic prostheses. Although surgical treatments have improved dramatically up to now, shoulder pathology is still challenging to orthopedic surgery primarily because these injuries often respond poorly to treatment and require prolonged rehabilitation. Recent attention has focused on several biologic pathways which can augment function to tendon healing, consequently leading to the identification of growth factors involved in this process. In this review, we discuss the studies published in these few years about these growth factors and their role in rotator cuff healing.

Abstract 5201: Identification of growth factors that promote the proliferation and drug resistance of human primary acute B lymphoblastic cells

Abstract Bone marrow mesenchymal stem cells (BMMSCs) contribute the survival, expansion, and drug resistance of leukemic cells. However, how BMMSCs promote the proliferation and drug resistance of leukemia remains to be poorly understood. Here, we derived a BM-derived stromal cell line that supported unlimited growth of human primary acute B lymphoblastic leukemic cells (B-ALL) by physical contacts with B-ALL cells and secreting growth factors. Nevertheless, its capacity of promoting primary B-ALL proliferation was abolished once the cell line was induced to differentiate into adipocytes. In xenograft models, we demonstrate that the presence of adipocytes suppressed the engraftment of primary B-ALL cells while the decrease of adipocytes enhanced the reconstitution of B-ALL. Consistently, we observed that the increase of numbers and diameters of adipocytes was correlated with remission after chemotherapy treatments in B-ALL patients. By comparing the global transcription profiles between the BM stromal cells and the adipocytes that were derived from the cell line, we identified a combination of cytokines and adherent proteins that were able to support the long-term growth of human primary B-ALL cells and desensitize them to chemotherapy drugs in a stromal-free culture condition. Furthermore, we showed that the PI3K/AKT pathways were involved in chemotherapy-induced resistance because targeting these signaling pathways increased the chemotherapy sensitivity of B-ALL in xenografts. Collectively, our results uncovered the mechanisms of BMMSCs supporting the survival, expansion, and drug resistance of human B-ALL cells. Citation Format: Peng Li, Zhiwu Jiang. Identification of growth factors that promote the proliferation and drug resistance of human primary acute B lymphoblastic cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5201.

Expression and functional studies of the GDNF family receptor alpha 3 in the pancreas.

The generation of therapeutic β-cells from human pluripotent stem cells relies on the identification of growth factors that faithfully mimic pancreatic β-cell development in vitro. In this context, the aim of the study was to determine the expression and function of the glial cell line derived neurotrophic factor receptor alpha 3 (GFRα3) and its ligand artemin (Artn) in islet cell development and function. GFRα3 and Artn expression were characterized by in situ hybridization, immunochemistry, and qRT-PCR. We used GFRα3-deficient mice to study GFRα3 function and generated transgenic mice overexpressing Artn in the embryonic pancreas to study Artn function. We found that GFRα3 is expressed at the surface of a subset of Ngn3-positive endocrine progenitors as well as of embryonic α- and β-cells, while Artn is found in the pancreatic mesenchyme. Adult β-cells lack GFRα3 but α-cells express the receptor. GFRα3 was also found in parasympathetic and sympathetic intra-islet neurons as well as in glial cells in the embryonic and adult pancreas. The loss of GFRα3 or overexpression of Artn has no impact on Ngn3 and islet cell formation and maintenance in the embryo. Islet organization and innervation as well as glucose homeostasis is normal in GFRα3-deficient mice suggesting functional redundancy.

Targeting the Angiopoietin-2/Tie-2 axis in conjunction with VEGF signal interference

Anti-angiogenic therapies target the tumor vasculature, impairing its development and growth. It was hypothesized over 40 years ago by the late Judah Folkman and Julie Denekamp that depriving a tumor of oxygen and nutrients, by targeting the tumor vasculature, could have therapeutic benefits. Identification of growth factors and signaling pathways important in angiogenesis subsequently led to the development of a series of anti-angiogenic agents that over the past decade have become part of the standard of care in several disease settings. Unfortunately not all patients respond to the currently available anti-angiogenic therapies while others become resistant to these agents following prolonged exposure. Identification of new pathways that may drive angiogenesis led to the development of second-generation anti-angiogenic agents such as those targeting the Ang-2/Tie2 axis. Recently, it has become clear that combination of first and second generation agents targeting the blood vessel network can lead to outcomes superior to those using either agent alone. The present review focuses on the current status of VEGF and Ang-2 targeted agents and the potential utility of using them in combination to impair tumor angiogenesis.

BRAIN TUMOUR INITIATING CELLS AND TARGETING STAT3 ONCOGENIC SIGNALLING IN GBM

BACKGROUND: Glioblastoma (GBM) is a devastating disease and the most lethal of adult brain tumours. Despite standard surgery, radiation and chemotherapy, the median survival is 15 months, thought to be due, in part, to recurrence from a small reservoir of brain tumour initiating cells. Our laboratory discovered adult neural stem cells, now found to be present in the brains of all adult mammals, through the development of the clonal neurosphere assay. This assay has contributed to the identification of adult human brain tumour initiating cells (BTICs), which may represent a reservoir that leads to GBM recurrence and death. Building upon the identification of growth factors and cytokines that converge on the cytoplasmic signal transducer and activator of transcription 3 (STAT3) to maintain the adult neural stem cell undifferentiated state, and the fact that STAT3 is abnormally active in GBM and may be one of the causes of tumour growth and therapeutic resistance, targeting the janus kinase (JAK)/STAT3 signalling pathway has become a major research focus for our laboratory. Here, we report the GBM translational potential of R333, a JAK/SYK inhibitor in development for other indications by Rigel Pharmaceuticals. METHODS: We have developed a cellular resource of more than 100 BTIC lines derived from GBM patients. Collaborative studies with academic and industry partners has resulted in the identification of promising therapeutic candidates that target JAK/STAT3 signalling in GBM. These compounds are tested for their ability to attenuate growth of BTICs in cell culture, on target activity in vitro and in vivo, and for their impact on the the survival of immunocompromised mice that have received BTIC xenografts. We employed this approach to examine the therapeutic potential of R333. RESULTS: In a collection of diverse patient-derived BTIC lines, R333 demonstrated potent, on-target JAK/STAT3 inhibition at low micromolar doses that effectively decreased BTIC viability and clonogenic potential, without affecting human fetal astrocytes. Importantly, R333 could be co-administered with temozolomide without reducing therapeutic response. Using phosphoproteomics, we confirmed the primary target of R333 in BTSCs as activated STAT3. In a BTIC orthotopic xenograft model, systemic treatment with R348, the pro-drug form of R333, resulted in BBB penetration and significant increased overall median survival without major side effects. CONCLUSIONS: These data suggest that R333 (R348) is a potent, BBB-permeable JAK/STAT3 inhibitor, worthy of further clinical evaluation for GBM treatment. These findings support our overall hypothesis that targeting the STAT3 signalling pathway may represent an effective therapeutic approach to managing GBM. SECONDARY CATEGORY: Tumor Biology.

Restoring the resting potential brings maturity to induced stem cell–derived human cardiac myocytes

Reprogramming of mature human cells to produce the equivalent of embryonic stem cells offers exciting possibilities for therapeutic tissue repair and artificial organs. A more immediate benefit is the possibility of testing potential new drugs and other therapies in human cells of any type that can easily be created in vitro without the use of human blastocysts and with a minimum of invasive procedures in patients. Fundamental research in embryology lead to the identification of growth factors that could be used to force cultured embryonic stem cells to differentiate into mature adult cells including atrial and ventricular cardiac myocytes. This work grew out of the initial approach of allowing the harvesting and subculturing regions of embryos growing in vitro that showed spontaneous beating. A spectacular advance came in 2006 when Takahashi and Yamanaka 1 showed that mouse or human adult fibroblasts could revert to pluripotent stem cells when exposed to 4 factors: Oct3/4, Sox2, c-Myc, and Klf4 under embryonic stem cell culture conditions. In 2012, Yamanaka received the Nobel Prize in Medicine or Physiology for this work, which he shared with Gurdon, who showed in l962 that the specialization of mature cells can be reversed by transplantation of a frog intestinal cell nucleus into a frog egg. By the time of this award, substantial work by others had shown what additional factors or conditions are needed to cause the so-called induced pluripotent stem (IPS) cells to differentiate into adult cardiac myocytes or other cellular components including vascular and endothelial cells. 2 In the heart, embryonic development and tissue differentiation is accompanied by important changes in the electrical activity that alter the cardiac action potential and underlying ionic currents. While the genome must contain sequence information for all ion channels in the heart and other tissues, the expression of the ion channels varies with the stage of embryonic development and with anatomic location. In the embryonic hearts of vertebrates, the action potential of the immature ventricle is similar to that found in the adult sinoatrial node. Specifically, there is spontaneous diastolic depolarization (the pacemaker potential) with a relatively low maximum diastolic potential in immature atrial and ventricular cells, which disappears during development. The upstroke of the action potential is mediated by calcium channels in the early embryo and by sodium channels in the late embryo and adult. The action potential upstroke becomes increasingly rapid during embryonic development, as demonstrated by Nathan and DeHaan 3 in the chick heart. Mature atrial and ventricular cells have a resting potential that is due to predominant permeability to potassium and is approximately � 90 mV, which is the potassium equilibrium

Rescue Screens with Secreted Proteins Reveal Compensatory Potential of Receptor Tyrosine Kinases in Driving Cancer Growth

The overall power of kinase inhibitors is substantially overshadowed by the acquisition of drug resistance. To address this issue, we systematically assessed the potential of secreted proteins to induce resistance to kinase inhibitors. To this end, we developed a high-throughput platform for screening a cDNA library encoding 3,432 secreted proteins in cellular assays. Using cancer cells originally dependent on either MET, FGFR2, or FGFR3, we observed a bypass of dependence through ligand-mediated activation of alternative receptor tyrosine kinases (RTK). Our findings indicate a broad and versatile potential for RTKs from the HER and FGFR families as well as MET to compensate for loss of each other. We further provide evidence that combined inhibition of simultaneously active RTKs can lead to an added anticancer effect.

Identification of Growth Factors Involved in Non-canonical (MCSF Independent) Pathways of Human Osteoclast Formation

Identification of Growth Factors Involved in Non-canonical (MCSF Independent) Pathways of Human Osteoclast Formation

Mesenchymal Stem Cells: Molecular Targets for Tissue Engineering

Mesenchymal stem cells (MSCs) represent an adherent, fibroblast-like population present not only in the bone marrow, but in a number of tissues, including blood, adipose tissue, muscle, and dermis. Their extensive proliferation and transdifferentiation potential makes them best suited for tissue engineering applications. Identification of growth factors and signaling pathways involved in self-renewal and differentiation is important for designing strategies to overcome replicative senescence and attain directed differentiation. Wnt, bone morphogenetic protein (BMP), and Notch pathways have been implicated to play key roles in self-renewal and differentiation of hematopoietic, intestinal, and epidermal stem cells. They are also involved in regulating MSC differentiation. However, MSC self-renewal has not received much attention, with Nucleostemin being the only recently identified proliferation molecule. Although immortalization using viral oncogenes and telomerase has been achieved, transformation in long-term cultures is a potential risk. Understanding of the mechanisms governing osteogenic differentiation of MSCs is expanding with the recent identification of two major transcription factors, Osterix and Runx2. Enhanced expansion as well as osteogenic differentiation of MSCs can be attained using a combinatorial approach involving co-expression of proliferation and differentiation genes. However, a thorough understanding of the molecular mechanism is necessary for enhancing the self-renewal ability and osteogenic potential in vitro.

Activin-Nodal signaling is involved in propagation of mouse embryonic stem cells

Embryonic stem (ES) cells are self-renewing cells that maintain pluripotency to differentiate into all types of cells. Because of their potential to provide a variety of tissues for use in regenerative medicine, there is great interest in the identification of growth factors that govern these unique properties of ES cells. However, the signaling pathways controlling ES cell proliferation remain largely unknown. Since transforming growth factor beta (TGFbeta) superfamily members have been implicated in the processes of early embryogenesis, we investigated their roles in ES cell self-renewal. Inhibition of activin-Nodal-TGFbeta signaling by Smad7 or SB-431542 dramatically decreased ES cell proliferation without decreasing ES pluripotency. By contrast, inhibition of bone morphogenetic protein (BMP) signaling by Smad6 did not exhibit such effects, suggesting that activin-Nodal-TGFbeta signaling, but not BMP signaling, is indispensable for ES cell propagation. In serum-free culture, supplementation of recombinant activin or Nodal, but not TGFbeta or BMP, significantly enhanced ES cell propagation without affecting pluripotency. We also found that activin-Nodal signaling was constitutively activated in an autocrine fashion in serum-free cultured ES cells, and that inhibition of such endogenous signaling by SB-431542 decreased ES cell propagation in serum-free conditions. These findings suggest that endogenously activated autocrine loops of activin-Nodal signaling promote ES cell self-renewal.

Cardiac specific differentiation of mouse embryonic stem cells.

Embryonic stem (ES) cells may represent an alternative source of functionally intact cardiomyocytes for the causal treatment of cardiovascular diseases. However, this requires cardiac-specific differentiation of stem cells and the selection of pure lineages consisting of early embryonic cardiomyocytes. Therefore, an understanding of the basic mechanisms of heart development is essential for selective differentiation of embryonic stem cells into cardiac cells. The development of cardiac cells from embryonic stem cells is regulated by several soluble factors and signalling molecules together with cardiac specific transcription factors such as the zinc-finger GATA proteins and Nkx-2.5. GATA-4 and Nkx-2.5 seem to be essential for heart development. The use of enhanced green fluorescent protein (EGFP) under the control of cardiac-specific promoters in combination with the ES cell system has allowed for the functional characterisation of cardiac precursor cells. Embryonic stem cell-derived cardiomyocytes developmentally express similar cardiac-specific proteins, ion channels and signalling molecules to that of adult cardiomyocytes. Furthermore, identification of growth factors and signalling molecules under cell culture conditions is crucial for the selective cardiac differentiation of embryonic stem cells. Therefore, serum-free culture conditions have to be established in order to examine the influence of different growth factors and signalling molecules on cardiac development and/or formation from ES cells. Although significant progress has been made in generating cardiac cell lineage by the combination of genetically manipulative methods with selective culture conditions for cell transplantation therapy, one of the remaining future challenges for transplantation in humans is the immunological rejection of the engrafted cardiomyocytes.

Identification of growth factors that promote long-term proliferation of olfactory ensheathing cells and modulate their antigenic phenotype

Olfactory ensheathing cells can develop into distinct subtypes in culture after incubation in serum-free medium conditioned by astrocytes, which have Schwann cell–like and astrocyte-like properties. It has not been possible so far to modulate and grow large numbers of these olfactory ensheathing cell subtypes. In this study, we have shown that astrocyte-conditioned medium, although promoting differentiation of the two olfactory ensheathing cell types, is growth-restrictive after 14 days, probably due to the upregulation of p16 and p27. Growth arrest can be overridden and cells maintained for a further 11 weeks, by a mitogen mix of fibroblast growth factor 2, forskolin, and heregulin (olfactory mitogen medium) combined with astrocyte-conditioned medium. In the absence of astrocyte-conditioned medium, combinations of the same factors can also override growth arrest but to a lesser extent. Olfactory mitogen medium combined with astrocyte-conditioned medium upregulates O4 and low-affinity nerve growth factor receptor expression on olfactory ensheathing cells, leading to a 100% Schwann cell–like phenotype. If cells are maintained in olfactory mitogen medium alone, or if they are treated with forskolin or fibroblast growth factor 2 diluted in serum-free medium, O4 and low-affinity nerve growth factor receptor expression remains at 100%, but there is also an increase in expression of E-NCAM, the astrocyte-like marker. Medium containing serum also overrides growth arrest, but for only 4 weeks, during which time most differentiation-specific markers disappear. These studies have allowed us to define conditions to modulate the olfactory ensheathing cell phenotype. GLIA 37:349–364, 2002. © 2002 Wiley-Liss, Inc.

Identification of growth factors that promote long‐term proliferation of olfactory ensheathing cells and modulate their antigenic phenotype

Olfactory ensheathing cells can develop into distinct subtypes in culture after incubation in serum-free medium conditioned by astrocytes, which have Schwann cell-like and astrocyte-like properties. It has not been possible so far to modulate and grow large numbers of these olfactory ensheathing cell subtypes. In this study, we have shown that astrocyte-conditioned medium, although promoting differentiation of the two olfactory ensheathing cell types, is growth-restrictive after 14 days, probably due to the upregulation of p16 and p27. Growth arrest can be overridden and cells maintained for a further 11 weeks, by a mitogen mix of fibroblast growth factor 2, forskolin, and heregulin (olfactory mitogen medium) combined with astrocyte-conditioned medium. In the absence of astrocyte-conditioned medium, combinations of the same factors can also override growth arrest but to a lesser extent. Olfactory mitogen medium combined with astrocyte-conditioned medium upregulates O4 and low-affinity nerve growth factor receptor expression on olfactory ensheathing cells, leading to a 100% Schwann cell--like phenotype. If cells are maintained in olfactory mitogen medium alone, or if they are treated with forskolin or fibroblast growth factor 2 diluted in serum-free medium, O4 and low-affinity nerve growth factor receptor expression remains at 100%, but there is also an increase in expression of E-NCAM, the astrocyte-like marker. Medium containing serum also overrides growth arrest, but for only 4 weeks, during which time most differentiation-specific markers disappear. These studies have allowed us to define conditions to modulate the olfactory ensheathing cell phenotype.

Hematopoietic Growth Factors

The identification of growth factors that stimulate the proliferation and maturation of hematologic cells has been a major advance in the fields of hematology and oncology. Production of these growth factors for clinical use has had a significant impact in these and other fields by reducing the morbidity and mortality associated with diseases and treatments. Availability of these growth factors has also expanded the treatment options for many patients, particularly those with malignant neoplasms. Furthermore, the use of hematopoietic growth factors has resulted in improved quality of life for many patients.

Therapeutic potential of neurotrophins for treatment of hearing loss.

Degeneration of spiral ganglion neurons (SGNs) and hair cells in the cochlea induced by aging, injury, ototoxic drugs, acoustic trauma, and various diseases is the major cause of hearing loss. Discovery of growth factors that can either prevent SGN and hair-cell death or stimulate hair-cell regeneration would be of great interest. Studies over the past several years have provided evidence that specific neurotrophins are potent survival factors for SGNs and protect these neurons from ototoxic drugs in vitro and in vivo. Current research focuses more on understanding the mechanism of hair-cell regeneration/differentiation and identification of growth factors that can stimulate hair-cell regeneration. SGNs are required to relay the signal to the central nervous system even when a cochlear implant is used to replace hair-cell function or in the case that cochlear sensory epithelium can be stimulated to regenerate new hair cells successfully. Therefore, neurotrophins may have their therapeutic value in prevention and treatment of hearing impairment.

A review of the microcirculation of adipose tissue: anatomic, metabolic, and angiogenic perspectives.

Adipose tissue microcirculation is unique within the vascular system because of a capacity for this tissue to grow throughout most of adult life. A review of the microcirculation of adipose tissue has included a historical review of the early studies, which served as a foundation for later investigations on this topic, including basic hemodynamic measurements in mammalian adipose tissue. The various methods for measuring blood flow in white and brown adipose tissue are discussed with respect to studies of transport of substrates involved in adipose tissue metabolism. The role of innervation and vascular adrenergic receptors and the effects of diet and exercise on adipose tissue blood flow are also included. An in-depth analysis of the development of adipose tissue microvasculature indicates that angiogenesis often precedes adipogenesis. The clinical effects of hemodynamic adaptations to adipose tissue expansion are discussed in view of an epidemic increase in the prevalence of obesity and its co-morbidities. The recent discovery of sites of nuclear regulation of adipocyte differentiation, together with the identification of growth factors in adipose tissue, is an indication of the progress that is being made in the further understanding of molecular and cellular events that affect adipose tissue growth and, ultimately, adipose tissue microcirculation.

Long-Term Survival of Transplanted Basal Forebrain Cells Followingin VitroPropagation with Fibroblast Growth Factor-2

The intracerebral transplantation of freshly dissected fetal tissue containing cholinergic neurons of the developing basal forebrain has been reported to reverse lesion-induced or age-related cognitive deficits in animal models of cholinergic neuronal degeneration. Grafts of cultured fetal neurons, however, have generally shown poor cellular survival and limited therapeutic benefit. We tested the hypothesis that recent advances in the identification of growth factors that promote the survival and propagation of fetal precursor cellsin vitrowould improve the long-term survival of cultured neurons following intracerebral implantation. Dissociated cells from gestational Day 14 rodent basal forebrain were grown in chemically defined media supplemented with 20 ng/ml basic fibroblast growth factor. Two weeks postplating, numerous cells were present in the cultures and showed immunoreactive labeling for a variety of markers, including glutamic acid decarboxylase, neuron-specific enolase, neurofilament proteins, glial fibrillary acidic protein and, occasionally, choline acetyltransferase. To determine if cultured basal forebrain cells would survive intracerebral implantation, the cells were implanted homotypically into the nucleus basalis magnocellularis. To enhance the potential for graft survivalin vivo,cells were also implanted into the nucleus basalis magnocellularis following an ibotenic acid lesion and into the denervated frontal cortex. Animals sacrificed between 2 weeks and 7 months following transplantation showed good and comparable graft survival in all sites. Immunocytochemical analysis revealed that representative populations of cells observedin vitrosurvived for prolonged periodsin vivo,even in sites distal from their normal cellular targets. Thus, neuronal populations expandedin vitrocan successfully survive and maintain cellular phenotypes post-transplantation. These results suggest a potential for isolating and growing specific neuronal populationsin vitrofor intracerebral transplantation.

Future directions in the treatment of non-small cell lung cancer: Shepherd FA. Toronto Hospital, 200 Elizabeth St, Toronto, Ont. M5G 2C4. Semin Oncol 1994;21:Suppl 4:48–62

In recent years significant advances have been made in the treatment of metastatic non-small cell lung cancer. These advances have been due to both the discovery of new, more active drugs and an enhanced understanding of the biology of the disease, which has guided treatment decisions. Today, agents such as paclitaxel, docetaxel, vinorelbine, irinotecan, and gemcitabine are used in combinations that have demonstrated higher overall response rates and longer median overall survival durations than the previous generation of regimens based primarily on cisplatin, etoposide, and vinblastine. Of these new agents, paclitaxel has been the most widely studied and has demonstrated considerable activity when administered in a wide range of doses and schedules. Regimens with significant activity include paclitaxel and carboplatin as well as paclitaxel, carboplatin, and gemcitabine. However, because the optimal doses and schedules have not been clearly elucidated, current research efforts continue to focus on variations of these regimens. Just as advances have been made in the treatment of metastatic disease, it also has been clearly demonstrated that preoperative chemotherapy (+/- radiation) dramatically improves the overall survival for patients with stage III disease. The identification of growth factors, growth factor receptors, oncogenes, and tumor suppressor genes, which influence this disease, is providing new targets for future treatment strategies. Likewise, new therapeutic entities such as antiangiogenesis agents and matrix metalloproteinase inhibitors are being evaluated.