Gastrin as an autocrine growth factor in colorectal carcinoma:implications for therapy

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Autocrine Production of Interleukin-6: A Mechanism of Interleukin-6 Independence in Dexamethasone-Resistant 7TD1 Murine Myeloma Cells

Several factors could contribute to proliferation of multiple myeloma (MM) cells independent of interleukin-6 (IL6) in the later stages of the disease. Our previous studies established a dexamethasone-resistant 7TD1 cell line (7TD1-Dxm) and have shown that one mechanism of resistance to dexamethasone is due to inhibition of cytochrome c release. We have also observed that 7TD1-Dxm cells proliferate independently of externally-added IL6. This study therefore aimed to elucidate the mechanisms responsible for IL6-independent proliferation in 7TD1-Dxm cells. Our results indicated that 7TD1-Dxm cells produced IL6 in an autocrine fashion. We have observed that dexamethasone-resistant 7TD1 cells become dexamethasone-resistant and IL6-independent for proliferation concomitantly. This strongly suggests that production of IL6 by 7TD1-Dxm cells may play an important role in the development of dexamethasone resistance. Consequently, further investigation of the molecular mechanisms responsible for IL6 production may be helpful in delineating the mechanisms leading to dexamethasone resistance.

MORPHOLOGICAL EVIDENCE FOR THE AUTOCRINE HYPOTHESIS

Autocrine secretion is a concept which emerges in the search for the molecular basis of malignant tumour. Tumour cells can produce endogenous polypeptide growth factors which act on their producer cells via functional external receptors. This process has been termed 'autocrine secretion'. Autocrine hypothesis explains the malignant growth of tumour cells satisfactorily. Transforming growth factor-α (TGF-α)is one of the typical autocrine growth factors. TGF-α can induce the reversible phenotypic transformation of normal rat kidney cells in the presence of other growth factors. This suggests that TGF-α may play an im-

Effect of Fuzhenghuayu decoction on vascular endothelial growth factor secretion in hepatic stellate cells

Objective: To investigate the effect of Fuzhenghuayudecoction on autocrine activation of hepatic stellatecell (HSC).Methods: The drug serum containing Fuzhenghuayudecoction was collected from normal rats, and cul-tured with activated HSC in vitro. The conditionedmedium from the drug serum treated HSC was addedto primary cultured quiescent HSC. Cell prolifera-tion was assayed by tetrazolium colorimetric test,and the contents of type Ⅰ collagen and vascular endo-thelial growth factor (VEGF) in the supernatantwere measured with ELISA.Results: The conditioned medium from activatedHSC could stimulate the quiescent HSC proliferationand type Ⅰ collagen secretion. The drug serum inhibi-ted this stimulating action and VEGF secretion fromthe activated HSC.Conclusion: Fuzhenghuayu decoction acts effectivelyagainst the autocrine activation pathway of HSC.The mechanism may be associated with the inhibitionof the secretion of VEGF by activated HSC.

Hepatopoietin Cn suppresses apoptosis of human hepatocellular carcinoma cells by up-regulating myeloid cell leukemia-1

AIM:To investigate the role of hepatopoietin Cn(HPPCn) in apoptosis of hepatocellular carcinoma(HCC)cells and its mechanism. METHODS:Two human HCC cell lines,SMMC7721 and HepG2,were used in this study.Immunostaining, Western blotting and enzyme linked immunosorbent assay were conducted to identify the expression of HPPCn and the existence of an autocrine loop of HPPCn/ HPPCn receptor in SMMC7721 and HepG2.Apoptotic cells were detected using fluorescein isothiocyanate (FITC)-conjugated Annexin V and propidium iodide.RESULTS:The HPPCn was highly expressed in human HCC cells and secreted into culture medium(CM). FITC-labeled recombinant human protein(rhHPPCn) could specifically bind to its receptor on HepaG2 cells. Treatment with 400 ng/mL rhHPPCn dramatically increased the viability of HCC-derived cells from 48.1% and 36.9%to 85.6%and 88.4%,respectively(P< 0.05).HPPCn silenced by small-interfering RNA reduced the expression and secretion of HPPCn and increased the apoptosis induced by trichostatin A.Additionally, HPPCn could up-regulate the expression of myeloid cell leukemia-1(Mcl-1)in HCC cells via mitogen-activated protein kinase(MAPK)and sphingosine kinase-1. CONCLUSION:HPPCn is a novel hepatic growth factor that can be secreted to CM and suppresses apoptosis of HCC cells by up-regulating Mcl-1 expression.

CO-EXPRESSION OF MACROPHAGE COLONY-STIMULATING FACTOR WITH ITS RECEPTOR IN HUMAN HEPATOMA CELLS AND ITS POTENTIAL ROLES

Objective: To investigate the potential role of macrophage colony-stimulating factor (M-CSF) and macrophage colony-stimulating factor receptor (M-CSFR) on the growth of human hepatoma cells. Methods:Specimens of different origin, including tissues of human hepatocellular carcinoma (HCC), human fetal liver (FL) and normal liver (NL), the hepatoma cell lines,as well as the peripheral blood mononuclear cells (PBMC) from patients with HCC or liver metastatic tumor (LMT), were used to detect the expression levels of M-CSF and M-CSF-R by ABC immunohistochemistry staining and reverse transcription polymerase chain reaction methods the expression levels of M-CSF and MCSF’R. Influence of monoclonal antibody against MCSF (BS) or M-CSF’R (RE2) on proliferation ability of hepatoma cell tilles in vitro was also studied. Results: The results showed that hepatoma tissues produced elevated levels of both M-CSF and M-CSF-R compared with those of fetal liver (P<0.001). The M-CSFIM’CSF-R expression levels of PBMC from hepatoma patients were higher than those of LMT patients (P<0.01, P<0.05) and the normal people (P<0.001). The hepatoma cell lines showed strong positive for M-CSF and M-CSF-R production. Both BS and REZ displayed a dosedependent inhibitory effect on the growth and proliferation of hepatoma cells. Conclusion: The study indicates a co-expression model for M-CSF-R in hepatoma cells, suggesting an involvement of M-CSFIMCSF-R in growth signaling of those malignant cells. The M-CSFIM-CSF-R seems to function through an autonomy mechanism in human hepatoma.

The expression of the products of IGF-Ⅱ,IGF-Ⅱ receptors and CSF-Ⅰ receptors in human primary hepatocellular carcinoma and juxtacancerous liver tissue

The expression of the products of IGF-Ⅱ,IGF-Ⅱ receptors(IGF-Ⅱ-R)and CSF-Ⅰ re-ceptors(CSF-Ⅰ-R)was observed in 17 cases of human primary hepatocellular carcinoma(PHC)and the juxtacancerous liver tissue with immunohistochemistry(ABC),Western blot and North-ern blot technique,It was found that the expression of IGF-Ⅱ,IGF-Ⅱ-R and CSF-Ⅰ-R was signif-icantly higher in PHC than in normal liver tissue and the expression of IGF-Ⅱ and IGF-Ⅱ-R wasremarkably higher in the juxtacancerous liver tissue from PHC patients than in PHC proper.Itwas noteworthy that the expression of IGF-Ⅱ in both the cancer proper and the juxtacancerousliver tissue was characterized by its fetal type.Besides,the expression of CSF-Ⅰ-R was signifi-cantly higher in PHC than in the juxtacancerous liver tissue.It is believed that the abnormal ex-pression of IGF-Ⅱ,IGF-Ⅱ-R and CSF-I-R in PHC and the juxtacaneerous liver tissue might berelated to the autocrine mechanism of human PHC.

Endothelin increases the proliferation of rat olfactory mucosa cells

The olfactory mucosa holds olfactory sensory neurons directly in contact with an aggressive environment. In order to maintain its integrity, it is one of the few neural zones which are continuously renewed during the whole animal life. Among several factors regulating this renewal, endothelin acts as an anti-apoptotic factor in the rat olfactory epithelium. In the present study, we explored whether endothelin could also act as a proliferative factor. Using primary culture of the olfactory mucosa, we found that an early treatment with endothelin increased its growth. Consistently, a treatment with a mixture of BQ123 and BQ788(endothelin receptor antagonists) decreased the primary culture growth without affecting the cellular death level. We then used combined approaches of calcium imaging, reverse transcriptase-quantitative polymerase chain reaction and protein level measurements to show that endothelin was locally synthetized by the primary culture until it reached confluency. Furthermore, in vivo intranasal instillation of endothelin receptor antagonists led to a decrease of olfactory mucosa cell expressing proliferating cell nuclear antigen(PCNA), a marker of proliferation. Only short-term treatment reduced the PCNA level in the olfactory mucosa cells. When the treatment was prolonged, the PCNA level was not statistically affected but the expression level of endothelin was increased. Overall, our results show that endothelin plays a proliferative role in the olfactory mucosa and that its level is dynamically regulated. This study was approved by the Comité d’éthique en expérimentation animale COMETHEA(COMETHEA C2 EA-45;protocol approval #12-058) on November 28, 2012.

THE CELL ORIGIN OF INTERLEUKIN 6 IN THE DISEASE OF MULTIPLE MYELOMA

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AMF siRNA treatment of keloid through inhibition signaling pathway of RhoA/ROCK1

A keloid(KD)is a benign dermal fibrotic tumor.Treatment of KDs is challenging and the recurrence rate is high;thus,there is an unmet need to explore new target sites and new treatment methods.As a tumor-associated cytokine,autocrine motility factor(AMF)can effectively stimulate the random and directional movement of cells.We first found that AMF was overexpressed in keloid fibroblasts(KFs)and the proliferation and migration of KFs were promoted by AMF stimulation.After treatment with Y-27632,RhoA kinase inhibitor,the proliferation and migration capacity of KFs declined significantly,and type I collagen protein,active RhoA and ROCK1 also were downregulated.In addition,a KD transplantation model was established under the skin of nude mice,with KD intramural injection AMF siRNA,we found that the weight of the KD was smaller than in the control group(P<0.05),KD tissue sections stained by HE and Masson showed that fibers became loose and the blood vessels were visibly reduced.In conclusion,AMF siRNA is expected to be a novel strategy to treat KD by inhibiting signaling pathway of RhoA/ROCK1.

FURTHER STUDY ON CHARACTERIZATION OF 615 MOUSE LEUKEMIC AUTOINHIBITORY ACTIVITY

There have been some reports on autocrine of leukemic cell lines, however, very few on leukemic negative autocrine up to date. It was demonstrated that some of leukemic cell lines could produce Tumor Necrosis Factor(TNF) and also its receptor. We have found an inhibitor from murine leukemia L7811 which could inhibit autologus leukemic cells. Later on leukemic cells from another 615 murine transplantable leukemia L615 was found to have similar autoinhibitor activit. Subsequently, it was confirmed that other

EXPRESSION OF TRANSFORMING GROWTH FACTOR-beta mRNA IN SOME LEUKEMIC CELLS

Bifunctional regulatory effects of TGF-beta for cell proliferation have been focused. TGFbeta becomes a candidate as the autocrine growth inhibitor to some malignant cells. Evidence has been gained in breast cancer cell. However, it has not been proved in leukemia and other tumors. Recently, regulations of external TGF-beta on normal and

ESTABLISHMENT OF A GROUP OF MURINE LEUKEMIC CELL LINES AND INVESTIGATION OF THEIR BIOLOGICAL CHARACTERISTICS

An in vitro-vivo technique for establishment of cell lines on murine leukemia has beendeveloped. Using this method, suppressive T lymphoblastic leukemia L7811-85, L7212-85, non-T, non-B lymphocytic leukemia L1210-86, B lymphocytic leukemia P 388-86 and Friend erythroleu-kemia FLCL cell lines have been established. Incidence of leukemia with these cell lines was 100%. Along with the increase of genera-tions of cell lines, cell growth accelerated, generation time shortened and cloning efficienciesrose. A following up electron microscopic observation on L7811-85 and L7212-85 showed thatthe virus particles were "A" particles in original cells. When they became cell lines in vitro,virus particles increased and transformed into typical "C" particles with budding. An inhibitory activity relevant to leukemic cells on proliferation of leukemic cells hasbeen observed in the supernatant of L7811-85 medium and was regarded as an "autocrine".

Crosstalk between glioblastoma and tumor microenvironment drives proneural–mesenchymal transition through ligand-receptor interactions

Glioblastoma(GBM)is the most common intrinsic and aggressive primary brain tumor in adults,with a median survival of approximately 15 months.GBM heterogeneity is considered responsible for the treatment resistance and unfavorable prognosis.Proneural-mesenchymal transition(PMT)represents GBM malignant progression and recurrence,which might be a breakthrough to understand GBM heterogeneity and overcome treatment resistance.PMT is a complicated process influenced by crosstalk between GBM and tumor microenvironment,depending on intricate ligand-receptor interactions.In this review,we summarize the autocrine and paracrine pathways in the GBM microenvironment and related ligand-receptor interactions inducing PMT.We also discuss the current therapies targeting the PMT-related autocrine and paracrine pathways.Together,this review offers a comprehensive understanding of the failure of GBM-targeted therapy and ideas for future tendencies of GBM treatment.