Growth Hormone In Vitro Experimental Study, Cholangiocarcinoma, Pancreatic Cancer Cell Proliferation And Its Mechanism

Growth Hormone(GH) is a proteohormone, a unity peptide with molecular weight being 22000U, secreted by acidophilic cell of anterior lobe of hypophysis. GH has been shown to accrue lean mass tissue and improve the volume and number of somatic cell, It can affect nearly all tissues, including bone,cartilage,adipose,immune system and generative system. In addition, GH influences organs growth, nervous system, haematological system, and other functions, such as acute or chronic reflection of protein metabolism and tissue structure, adjustion of body fluid balance, metabolism of carbohydrate and lipid. Protein balance in body is mostly determined by that of protein metabolism. However, under other condition, such balance may undergo a series of changes through many non-hormone factors, as malnutrition and infection.Since 1989, Serono Lit. Cop successfully manufactured the recombined human growth hormone(rhGH). Growth hormone has been widely applied in GH-deflciency patients, and it has been confirmed that GH can promote immune functions, protein synthesis and ameliorate nutritional status. Clinicians have saved many non-tumor patients lives using GH which can mitigate the loss of protein in body and mass tissues. Malnutrition and negative nitrogen balance greatly discounts curative effect and rise fatality rate, so it's urgent to ameliorate the whole nitrogen balance. Nevertheless, concerning the accelerating proliferation influence of GH, usage of GH on patients with cancer is still confined. Although we have arguments on the effect caused by GH which can potentially stimulate tumor cell proliferation, researches have showed that exogenous GH can delay the total protein loss time, improve nutrition, increase body weight, reinforce chemo-effect, depress chemo-toxicity, promote cellular and humoral immune function, relieve cachexia and be benefit for the host. In this case, GH can decrease fatality rate of the tumor-bearing host. GH, as mitogen, it can promote cell renewing and increase cell malignant transformation, so it may intensify tumor cell malignant action. In view of this, many clinicians insisted that we should be cautious about the GH using.Combination of the recent researches result, we still face many unsolved problems about GH effect on the tumor genesis and development. For example: 1)The question whether GH has proliferation effect on tumor cell may has different results, such as possibly for different pathology type of tumor cell, research method and observation time; 2)lack of prospective study; 3)diversity of vitro and vivo experiment, animal experiment and clinic try; 4) deficiency of systemic research on mechanism action; 5)quality of epidemiologic survey: in case selection, be ware of whether children has tumor high risk factor, whether adult has enough follow-up visit, whether the data come from the same center, also differences of GH dosage, drug-intake time, therapeutic effect related to variety patients.In view of this, we took bile duct carcinoma cell and pancreatic carcinoma cell as research target, and did a series of study in vitro. We tried to illustrate the effect of exogenous GH on proliferation of these two-team tumor cells, using flow cytometer to observe feature of cell cycle kinetics affected by GH, contrasted by the control group taken by placebo, detect IGF1/2 secreted by tumor cell with ELISA method, meanwhile, detect IGF 1/2RmRNA expression using hybridization in situ after fixation of the cells. It was the first time to illuminate the possible mechanism of GH effect on carcinoma of bile duct cell and pancreatic carcinoma cell with protein/gene approach. Relevant experimental protocol and results were provided as follows:Part A: The effect of GH on proliferation of bile duet carcinoma cell and pancreatic carcinoma cell and on cell cycle kinetics.The bile duct carcinoma cell line QBC939 and pancreatic carcinoma cell line BXPC-3 were cultured and harvested during exponential growth stage in vitro and divided into experimental group(group GH) and control group(group NS). The experimental group was separated into four sub-groups [50ng/ml2h(GH50-2h), 50ng/ml24h(GH50-24h), 100ng/ml2h(GH100-2h), 100ng/ml24h(GH 100-24h)] according to the dose of GH and culture time. The control group was also divided into two sub-groups(NS-2h, NS-24h) by the culture time. After 2h,24h, Insulin-like Growth Factorl/2 were detected by ELISA respectively. The results revealed that exogenous GH stimulated cell growth and growth hormone also elevated percent S phase and proliferation index(PI) of cells after 24-hour culture, without significant relation with GH dosage.Part B: The effect of GH on IGFs secreted by tumor cells and expression of IGFsRmRNA in cytoplasmCell QBC939 and Cell BXPC-3 were divided into experimental group(group GH) and control group(group NS) during exponential growth stage and cultured 2 hours and 24 hours respectively, the concentration of IGFs detected with ELISA method in the centrifugated supernatant liquid. The expresstion of IGF1/2RmRNA were detected with hybridization in situ after cells were fixed.To summarize, we can make a conclusion from this study as follows: Growth hormone stimulates QBC939 cell and BXPC-3 cell growth in vitro, and elevates percent S phase and proliferation index(PI) of cells and, intensifies IGF1 secretion excreted by tumor cells, but it doesn't accelerate IGF2 secretion. IGFsRmRNA is expressed in tumor cells, but only IGF1RmRNA is impacted by GH, which means GH-IGF1 axis may be major one of its mechanisms.