Mouse S180 Sarcoma Research Articles

GFAP palmitoylcation mediated by ZDHHC23 in spinal astrocytes contributes to the development of neuropathic pain

BackgroundCancer pain has a significant impact on patient’s quality of life. Astrocytes play an important role in cancer pain signaling. The direct targeting of astrocytes can effectively suppress cancer pain,...

Structural characteristics and anti-tumor effect of low molecular weight Dendrobium officinale polysaccharides by reconstructing tumor microenvironment

In this study, glucanase and mannanase were selected to hydrolysis DOP to obtain low molecular weight DOP (LMWDOP), namely glucanase-hydrolysis Dendrobium officinale polysaccharides (GDOP) and mannanase-hydrolysis Dendrobium officinale polysaccharides (MDOP). The antitumor activity of LMWDOPs and its effect on tumor immune microenvironment were investigated. The growth of transplantable S180 sarcoma in mice was significantly inhibited by GDOP, and MDOP in a dose-dependent manner compared with the model group (P < 0.05, P < 0.01). This indicated that mannanase-hydrolysis Dendrobium officinale polysaccharides have stronger anti-tumor activity. The structure of MDOP was systematically characterized to explore the structure–activity relationship. The average molecular weight of MDOP was 3494 Da. MDOP had a linear chain structure consisting mainly of →6)-α-d-Glcp-(1→ and →4)-β-d-Manp-(1 → residues. O-acetyl group linked to C2 of →4)-β-d-Manp-(1 → residue. In conclusion, it has been determined that the small molecule dendrobium polysaccharides obtained from the hydrolysis of mannanase have good anti-tumor activity and can reconstruct the immune microenvironment. “→ 6-α-d-Glcp- (1 → 4)-β-d-Manp-(1→) may be the structural basis for Dendrobium officinale polysaccharides to exert anti-tumor effects.

Preparation and anti-tumor effect of pig spleen ethanol extract against mouse S180 sarcoma cells in vivo

Numerous studies have shown that extracts derived from animal spleens have anti-tumor effects, but the biological activity of ethanol extract obtained from pig spleen has not been tested. Therefore, in the present study, we used ethanol as the extraction solvent to obtain the pig spleen ethanol extract (PSE) with immune activity, which provided a theoretical basis for further development and utilization of pig spleen as an anti-tumor drug. Then the structure characteristics and immune activity of PSE were investigated. According to the characterization analysis results, PSE was a high-purity protein complex mainly composed of hydrophobic amino acids, with an average molecular weight of 2.66 × 106 Da. The secondary structure was mainly α-helix and β-sheet. In vivo, PSE inhibited the growth of the S180 tumor, and immune organ toxicity was not detected. PSE induced S180 tumor cells to block and apoptosis in the S phase through the ROS-mediated mitochondrial pathway. Meanwhile, PSE improved the immunity of the body, such as promoting the proliferation activity of lymphocytes and increasing the level of IgG. In conclusion, PSE had significant cytotoxic and antiproliferative effects on S180 sarcoma cells.

Synthesis and Antitumor Activity of (3-Hydroxyacrylato-O,O′) Diammineplatinum(II)

AbstractAs an indispensable part of cancer chemotherapy, platinum drugs still play an important role in cancer treatment. In this study, two platinum(II) complexes with Michael acceptor 3-hydroxyacrylic acid as the leaving group were synthesized from cis-diamminediiodo platinum(II) and 3-ethoxyacrylic acid. The structures of complexes 1 and 2 were confirmed by elemental analysis, infrared, 1H NMR, 13C NMR, and HRMS (high-resolution mass spectrometry). Results from MTT assay showed that complexes 1 and 2 significantly inhibited the growth of the four human tumor cell lines (HCT-116, A549, CFPAC-1, and BxPC-3) with the IC50 values of the two compounds similar to that of the control drug (oxaliplatin) on HCT-116 and A549. Besides, results from an in vivo study in a mouse S180 sarcoma model showed that complex 1 had a higher antitumor activity in comparison to oxaliplatin. In conclusion, our article indicated that complex 1 deserved further research and development in cancer treatment.

Anti-tumor and immunomodulatory activity of peptide fraction from the larvae of Musca domestica

Ethnopharmacological relevanceThe larvae of Musca domestica (Diptera: Muscidae) have been used traditionally for malnutritional stagnation, decubital necrosis, osteomyelitis, ecthyma and lip scald and also to treat coma and gastric cancer in the traditional Chinese medicine. Its in vitro antitumor activity and immunomodulatory effect in naïve mice in relation to the traditional uses were also reported. However, the in vivo antitumor effect of this insect and its mechanism of action have not yet been well studied. The objectives of this study were to evaluate the in vivo antitumor potential of the peptide fraction from Musca domestica larvae (MDPF) and to elucidate its immunological mechanisms. Materials and methodsThe mice inoculated with sarcoma S180 cells were orally administered with MDPF at three doses for 10 days. The effects of MDPF on the growth of mouse S180 sarcoma, splenocyte proliferation, the activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTLs), production and mRNA expression of cytokines from splenocytes, and serum antigen-specific antibody levels in tumor-bearing mice were measured. ResultsMDPF could significantly not only inhibit the growth of mouse transplanted S180 sarcoma, but also promote splenocytes proliferation, NK cell and CTL activity from splenocytes, and enhance serum antigen-specific IgG, IgG2a and IgG2b antibody levels in S180-bearing mice. MDPF also significantly promoted the production of IFN-γ and up-regulated the mRNA expression levels of IFN-γ and Th1 transcription factors T-bet and STAT-4 in splenocytes from the S180-bearing mice. However, Th2 cytokine IL-10 and transcription factors GATA-3 and STAT-6 were not significantly changed both at transcriptional and protein levels following MDPF treatment. ConclusionsMDPF significantly inhibit the growth of transplantable tumor in mice and its in vivo antitumor activity might be achieved by switching-on of Th1-based protective cell-mediated immunity. MDPF could act as antitumor agent with immunomodulatory activity.

Effects of black yeast-derived β-1,3-1,6-glucan on serum cytokine and microRNA expression in transplanted sarcoma in mice

β-1,3-1,6-glucans are the most abundant glucose polymers in the cell walls of fungi. Previous studies have shown that β-1,3-1,6-glucans derived from fungi possess immunomodulating activitivies. Antitumor effects of these compounds have also been reported in animal models. Current studies mainly focus on the direct effects of β-1,3-1,6-glucans on immune systems, but no data are available to address the underlying molecular events in tumor cells. β-1,3-1,6-glucan purified from black yeast at 5 mg/100 g body weight (study group) or saline (control group) was intragastrically administered on a daily basis to subcutaneously-injected mice with mouse S180 sarcoma cells. Tumor sizes, tumor weights, serum concentrations of cytokines and levels of microRNAs (miRNAs) in transplanted tumors were compared between the treated and control groups. The volumes and weights of transplanted tumors were significantly lower in the treatment groups compared to the control groups by ∼150% and 70%, respectively. The treated mice demonstrated significantly higher levels of cytokines, including IL-2, IL-4, IL-6, IL-8, IL-10 and IL-12, compared to the control mice. Notably, the expression of several miRNAs in transplanted tumor tissues also markedly changed. These data suggest that black yeast-derived β-1,3-1,6-glucan, not only stimulates cytokine release from immune cells, but also changes the expression profiles of miRNAs in transplanted tumors.

Sonodynamic and photodynamic therapy in advanced refractory breast cancer.

118 Background: Sonodynamic therapy (SDT), a procedure related with photodynamic therapy, is a promising new modality for treating deep-seated cancer. Two new chlorophyll derived sono-photo-sensitizing agents, along with equipment for systemic SDT, have been developed by EEC Biotech and all approved by regulator for safety on human. Animal studies demonstrate that the sensitizers are specifically absorbed into tumor cells and SDT does inhibit growth of mouse S-180 sarcoma. An in vitro experiment with human breast cancer cell-line showed that SDT was strongly synergetic with chemotherapy. Using sono-photo-dynamic therapy (SPDT) as a supplementary or salvage treatment, we have got some positive results in advanced refractory breast cancers. Methods: Twelve patients were pathologically proven advanced breast carcinoma. Eleven had metastases in viscera including brain, and nine in bones. Ten had chemotherapy before, nine failed at least second lines of conventional chemotherapy. With SPDT, Patients took the sensitizers sublingually on days 1 and 2, red light and multiple ultrasound transducers irradiate tumor area and whole body on days 4 to 6. The treatment was repeated. Nine patients had concurrent chemo with range from moderate to ¼ conventional dosages selected to keep side effects at grade II or better. Results: The twelve patients achieved CR 3(25%), PR 6 (50%), MR 1, SD 2, with an overall response rate of 75%.Median overall survival exceeded 14.5 months. SPDT as sole therapy was effective in three cases. Four treated repeatly with SPDT also achieved positive result after tumor relapsed. One patient with brain metastases showed much reduced. The two SD were TNBC with inflammation-like metastases on the chest surface. The main SPDT side effects were easily reversible mild pain in tumor areas, tiredness and weakness.There was no skin sensitivity.SPDT/dose controlled chemo was well tolerated, even a terminally ill patient was treated safely and effectively. Conclusions: These preliminary data suggest that SPDT has almost no toxicity, and may dramatically enhance chemo efficacy in some refractory advanced breast cancer cases. SPDT has a good trend to be a new systemic, low toxicity tumor therapy and merit for further investigation.

De novo design, synthesis and biological evaluation of 1,4-dihydroquinolin-4-ones and 1,2,3,4-tetrahydroquinazolin-4-ones as potent kinesin spindle protein (KSP) inhibitors

Kinesin spindle protein (KSP) inhibitors are a promising class of anticancer agents that cause mitotic arrest in cells from a failure to form functional bipolar mitotic spindles. Here, we report the design, synthesis and biological evaluation of a novel series of 1,4-dihydroquinolin-4-ones and 1,2,3,4-tetrahydroquinazolin-4-ones using de novo design method. The synthesized compound was evaluated and proved to have potent inhibitory activities in the KSP ATPase. Compounds 15j and 15p show potent inhibitory activities in cell proliferation assays. Preferred compound 15j markedly induced G2/M phase cell cycle arrest with characteristic monoastral spindles and subsequent cell death in A549 cells. In vivo evaluation of 15j on the growth of transplantable S180 sarcoma in mice suggested its therapeutic potential for further development.

Isolation of a polysaccharide with anticancer activity from Auricularia polytricha using high-speed countercurrent chromatography with an aqueous two-phase system

Polysaccharides from a crude extract of Auricularia polytricha were separated by high-speed countercurrent chromatography (HSCCC). The separation was performed with an aqueous two-phase system of PEG1000–K 2HPO 4–KH 2PO 4–H 2O (0.5:1.25:1.25:7.0, w/w). The crude sample (2.0 g) was successfully separated into three polysaccharide components of AAPS-1 (192 mg), AAPS-2 (137 mg), and AAPS-3 (98 mg) with molecular weights of 162, 259, and 483 kDa, respectively. These compounds were tested for growth inhibition of transplanted S180 sarcoma in mice. AAPS-2 had an inhibition rate of 40.4%. The structure of AAPS-2 was elucidated from partial hydrolysis, periodate oxidation, acetylation, methylation analysis, and NMR spectroscopy ( 1H, 13C). These results showed AAPS-2 is a polysaccharide with a backbone of (1 → 3)-linked-β- d-glucopyranosyl and (1 → 3, 6)-linked-β- d-glucopyranosyl residues in a 2:1 ratio, and has one terminal (1→)-β- d-glucopyranosyl at the O-6 position of (1→3, 6)-linked-β- d-glucopyranosyl of the main chain.

Anti-tumor activity of safflower polysaccbaride(SPS) and effecton cytotoxicity of CTL cells,NK cells of T739 lung cancer in mice

To study the anti-tumor activity of SPS in vivo and in vitro and the cytotoxicity of CTL cells, NK cells of T739 lung cancer in mice. The transplanted tumor model of S180 Sarcoma was established with KM mouse. The SPS was adminished i.p. for 10 d, the tumor weight was detected. The transplanted tumor model of LA795 lung cancer was established with T739 mouse and SPS was adminished i.p. for 10 d and the tumor weight and the cytotoxicity of CTL cells, NK cells were detected. The Anti-tumor activity of SPS on three types of tumor cells in vitro was observed with trypan blue exclusion staining. SPS 40 mg x kg(-1) can significantly inhibit the growth of S180 Sarcoma in mice and inhibitory rate was 51.33% (P<0.01). It can also inhibit the growth of LA795 lung cancer in mice and the tumor volume was reduced obviously for 3.29 mm3 (P<0.05). It can remarkably enhance the cytotoxicity of splenic CTL cells, NK cells in tumor-bearing (P<0.05). SPS have anti-tumor effects, the mechanism of the anti-tumor activity may be related to enhance the cytotoxicity of CTL cell and NK cell.

Chemical composition and antitumor activity of different polysaccharides from the roots of Actinidia eriantha

Four polysaccharides (AEPA, AEPB, AEPC and AEPD) isolated and purified from the roots of Actinidia eriantha using gel filtration were subjected to composition analysis and valuated for the antitumor and immunomodulatory activity. The predominant neutral monosaccharides in four fractions were identified as galactose, arabinose and fucose, while the composition and ratio of the monosaccharides were different from one another. All four polysaccharides could significantly not only inhibit the growth of transplantable S180 sarcoma in mice, but promote splenocytes proliferation, natural killer cells activity, interleukin-2 production from splenocytes and serum tumor antigen-specific antibody levels in tumor-bearing mice, indicating that their antitumor activity might be achieved by improving immune response. Among four polysaccharides, AEPC and AEPD showed the higher antitumor and immunomodulatory activity. Taken together, the chemical composition of these polysaccharides could affect their antitumor and immunomodulatory activity, and AEPC and AEPD could be explored as antitumor agent with immunomodulatory activity.

The Tumoricidal Effect of Sonodynamic Therapy (SDT) on S-180 Sarcoma in Mice

There are increasing data showing that sonodynamic therapy (SDT), which refers to a synergistic effect of drugs and ultrasound, is a promising new modality for cancer treatment. However, few clinical data on SDT have been published. One reason is the lack of suitable drugs for clinical SDT use. Recently a new sonosensitizing agent has been developed by SonneMed, LLC, referred to as SF1. In this study the effect of SDT with SF1 on S-180 sarcoma in mice was examined. The tumor bearing mice were allocated to the following groups: (1) sham-treatment (control, C); (2) ultrasound treatment (only ultrasound treatment, 1.2 mW/cm2 , without SF1, U); (3) SF1 treatment (SF1 20 mg/kg intraperitoneal [ip] without ultrasound treatment, S); and (4) SF1 + ultrasound treatment (SU). Following treatment, tumor volume was monitored. Tumor growth inhibition was seen only in group SU, and with increasing ultrasound intensity, the inhibitory effect was enhanced. Tumor growth inhibition was also visible even when covered by a barrier of bone. Pathological slices showed coagulated necrosis or metamorphic tissue with inflammatory reaction in the tumor taken from 2 to 36 hours after SDT. These data revealed that SDT with SF1 did inhibit growth of mouse S-180 sarcoma and the inhibitory effect was sound intensity dependent. SDT also induced some inflammation while it destroyed the tumor, indicative of a "vaccine" effect. SF1 shows great promise for clinical use in the future.

Antitumor effect and mechanism of Gecko on human esophageal carcinoma cell lines in vitro and xenografted sarcoma 180 in Kunming mice

To investigate the anti-tumor effect of Chinese medicine Gecko on human esophageal carcinoma cell lines and xenografted sarcoma 180 in Kunming mice and its mechanism. The serum pharmacological method was used in vitro. The growth rates of the human esophageal carcinoma cells (EC9706 or EC1) were measured by a modified 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The transplanted tumor model of the mouse S180 sarcoma was established. Fifty mice were randomly divided into five groups (n=10). Three Gecko groups were treated respectively with oral administration of Gecko powder at a daily dose of 13.5 g/kg, 9 g/kg, and 4.5 g/kg. The negative group (NS group) was treated with oral administration of an equal volume of saline and the positive group (CTX group) was treated with 100 mg/kg Cytoxan by intraperitoneal injection at the first day. After 2 wk of treatment, the anti-tumor activity was evaluated by tumor tissue weighing. The impact on immune organ was detected based on the thymus index, spleen index, phagocytic rate and phagocytic index. The protein expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were detected by immunohistochemistry. The cell apoptotic rate was detected by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay. The OD value in each group treated with Gecko after 72 h was reduced significantly in EC9706 and in EC1. The tumor weight in each group of Gecko was decreased significantly (1.087+/-0.249 vs 2.167+/-0.592; 1.021+/-0.288 vs 2.167+/-0.592; 1.234+/-0.331 vs 2.167+/-0.592; P<0.01, respectively). However, the thymus index and Spleen index of mice in Gecko groups had no significant difference compared with the NS group. The immunoreactive score of VEGF and bFGF protein expression of each Gecko group by immunohistochemical staining were lowered significantly. The apoptosis index (AI) of each group was increased progressively with increase of dose of Gecko by TUNEL. Gecko has anti-tumor effects in vitro and in vivo; induction of tumor cell apoptosis and the down-regulation of protein expression of VEGF and bFGF may be contributed to anti-tumor effects of Gecko.

Identification and Biological Characterization of Angiogenic and Tumor Growth Inhibitors derived from Sinica cetorhinus maximum Cartilage

Shark (Sinica cetorhinus maximum) cartilage was extracted in 1 mol/L Gu-HCl guanidine. Two purified active proteins with apparent molecular weights of 15.2x103 Da and 8.0×103 Da (designated as Sp15 and Sp8, respectively) were obtained through ultrafiltration and Superdex 75 chromatography. The activities of the samples were studied in terms of their potential inhibition of vascular endothelial cell growth in vitro, of angiogenesis both in rabbit cornea and chick embryo chorioallantoic membrane (CAM) assay models in vivo, and of growth of transplanted S180 sarcoma in mice in vivo. The results showed that Sp15 expressed a typical lysozymatic activity up to 223,000 U/mg and its N-terminus was highly homologous to lysozymes of various mammalian origins. Sp15 exhibited a strong anti-angiogenic activity only in vitro, whereas Sp8 shared this effect both in vitro and in vivo. Both Sp15 and Sp8 provided an effective anti-tumor activity in mice bearing transplanted S180 sarcoma. These results suggest that Sp15 is a shark cartilage-derived lysozyme that participates in the defense to bacterial invasion to the body, while Sp8 is an angiogenic inhibitor that mediates at least part of the anti-tumor activity associated with shark cartilage probably through the inhibition of tumor-induced angiogenesis.

Intercedensides A-C, three new cytotoxic triterpene glycosides from the sea cucumber Mensamaria intercedens Lampert.

Three new triterpene glycosides, intercedensides A (1), B (2), and C (3), were isolated from the sea cucumber Mensamria intercedens Lampert, which is found in the South China Sea, and their structures have been elucidated by spectroscopic analysis (NMR and ESIMS) and chemical transformations. Intercedensides A (1) and C (3) have a conjugated double bond (22E,24-diene) in the side chain of the aglycon. Intercedenside B (2) has two beta-D-xylose and two sulfate groups in the carbohydrate chain. All three glycosides showed significant cytotoxicity against 10 human tumor cell lines with ED(50) in the range 0.6-4.0 microg/mL. Intercedenside A (1) exhibited significant in vivo antineoplastic activity against mouse Lewis lung cancer and mouse S180 sarcoma. On the basis of these initially promising results, intercedensides A-C merit further study as potential anticancer agents.

Experimental studies on extremely low frequency pulsed magnetic field inhibiting sarcoma and enhancing cellular immune functions

The previous observation with an electron microscope showed that extremely low frequency (ELF) pulsed magnetic field (PMF) (with the maximum intensity of 0.6-2.0 T, gradient of 10-100 T*M(-1), pulse width of 20-200 ms and frequency of 0.16-1.34 Hz) inhibited the growth of S-180 sarcoma in mice and enhanced the ability of immune cell's dissolving sarcoma cells. In this study, the DNA contents of nuclei were assayed by using Faulgen Staining method. With an electron microscope and cell stereoscopy technology it was observed that magnetic field affected the sarcoma cell 's metabolism, lowered its malignancy, and restrained its rapid and heteromorphic growth. The magnetic field enhanced the cellular immune ability and the reaction of lymphocytes and plasma. Since ELF pulsed magnetic fields can inhibit the growth of sarcomas and enhance the cellular immune ability, it is possible to use it as a new method to treat cancer.

Tumor cell-conditioned medium stimulates expression of the urokinase receptor in vascular endothelial cells.

We have previously reported that culture medium conditioned by human SK-Hep1 hepatoma cells or mouse S180 sarcoma cells induces in vitro angiogenesis and stimulates production of urokinase plasminogen activator (uPA) in vascular endothelial cells. These activities are mediated by a 3.5-10 kDa, heparin-binding peptide that upregulates endothelial cell expression of basic fibroblast growth factor (bFGF; Peverali et al., 1994, J. Cell. Physiol. 161:1-14.) We now report that SK-Hep 1 or S180 cell-conditioned medium rapidly induces a 4- to 5-fold increase in cell-bound uPA activity and in the high-affinity binding of 125I-prouPA to vascular endothelial cells. Ligand blotting and purification experiments show an equivalent increase in the synthesis of a cell surface protein corresponding to the endothelial cell uPA receptor (uPAR) on the basis of M, (45-50 kDa) and sensitivity to phosphatidylinositol-specific phospholipase C (PI-PLC). The tumor cell-conditioned media also upregulate uPAR mRNA levels in endothelial cells. Thus, the increase in uPA binding capacity of endothelial cells is mediated by an increased expression of uPAR. The uPAR-inducing activity of SK-Hep 1 or S180 cell-conditioned medium is not neutralized by antibodies to bFGF, and is associated with a peptide that has a M, higher than 10 kDa and no affinity for heparin. Therefore, it appears to be distinct from the bFGF/uPA-inducing factor secreted by the same cells, and from other heparin-binding cytokines that upregulate uPAR expression in endothelial cells.

Tumor cells secrete an angiogenic factor that stimulates basic fibroblast growth factor and urokinase expression in vascular endothelial cells.

Culture medium conditioned by human SK-Hep1 hepatoma cells or mouse S180 sarcoma cells rapidly up-regulates endothelial cell expression of basic fibroblast growth factor (bFGF) and induces formation of capillary-like structures by vascular endothelial cells grown on three-dimensional fibrin gels (in vitro angiogenesis). Incubation of endothelial cells with the tumor cell-conditioned media also results in increased expression of urokinase plasminogen activator (uPA), a key component of the proteolytic system required for cell invasion and capillary formation. Although the tumor cell-conditioned media contain no bFGF, addition of anti-recombinant bFGF IgG abolishes the up-regulation of uPA and blocks in vitro angiogenesis. This indicates that both the increase in uPA production and formation of capillary-like structures are mediated by endogenous bFGF expressed by the endothelial cells. Both the bFGF/uPA-inducing activity and the angiogenic activity of SK-Hep1 cell-conditioned medium copurify with a relatively acid-resistant peptide that has moderate affinity for heparin and M(r) < 18 kDa > 3.5 kDa. Known cytokines with similar biochemical features do not possess the same biological activity. These findings indicate that angiogenesis can be mediated by endothelial cell bFGF through an autocrine mechanism and that the bFGF-inducing peptide may represent a novel tumor-derived angiogenic factor that modulates in endothelial cells the concerted expression of cytokines and proteolytic enzymes required for capillary formation.

Biological and biochemical properties of nerve growth factor synthesized by mouse S-180 cells in culture

Nerve Growth Factor (NGF), a protein involved in the maintenance and differentiation of sensory and sympathetic neuronal cells [1], is synthesized by several different types of cells in culture [2–7]. In this paper, the biochemical and biological properties of NGF synthesized by a mouse S-180 sarcoma cell line were examined. These cells do not appear to produce the 7S-NGF molecule, a form of NGF found in high concentrations in the mouse submandibular gland [8]. The 7S-NGF is comprised of three distinct protein subunits named β-NGF, α and γ [9]. Although the S-180 cells do not produce 7S-NGF, the cells do synthesize one of the component subunits of 7S-NGF, the β-NGF subunit. Biological, electrophoretic, immunological and molecular weight criteria were used to establish that the β-NGF synthesized by the S-180 cells is very similar to the submandibular gland β-NGF. The S-180 β-NGF was bound to an unidentified binding component(s) which is not immunologically similar to either the α- or γ-subunit. The functional significance of this interaction is not known.

S-180 cells secrete nerve growth factor protein similar to 7S-nerve growth factor.

The nerve growth factor protein (NGF) has been identified by biological assay and rocket immunoelectrophoresis in media conditioned by monolayers of mouse S-180 sarcoma cells, a transformed cell line of salivary gland origin. By utilization of a purification procedure designed to enrich for acid-dissociable, high-molecular-weight complexes similar to the 7S-NGF isolated from male mouse submaxillary gland, it has been determined that a significant portion of mouse sarcoma NGF is initially present as a complex at neutral pH with a molecular weight indistinguishable from that of 7S-NGF. At pH 4.0 the mouse sarcoma NGF complex dissociates, and the active subunit can be isolated as a species with a molecular weight of less than 40,000. The induced dissociation at pH 4.0 of the mouse sarcoma NGF high-molecular-weight complex, as well as the complex's behavior in isoelectric focusing and sucrose gradient sedimentation is consistent with the hypothesis that 7S-NGF is packaged as a subunit containing protein intracellularly prior to secretion into the extracellular space. Moreover, the stability of the mouse sarcoma NGF complex at dilute concentrations is similar to that reported for the purified 7S-NGF complex.