Repairing effects of interleukin 11 (IL-11) towards high dose methotrexate-induced rat small intestinal mucositis and its impacts on T-lymphoblastic leukemia cell line

Headnote

ARTICLE INFO

Article type:

Original article

Article history:

Received: Jun 7, 2015

Accepted: Mar 3, 2016

Keywords:

CEM cell line

Interleukin 11

Methotrexate

Mucositis

ABSTRACT

Objective(s): To investigate the efficacy of interleukin 11 (IL-11) towards the high dose methotrexate (HDMTX)-concurrent rat small intestinal mucositis and its impacts on the proliferation of the human T-lymphoblastic leukemia (CEM) cell line.

Materials and Methods: 95 Wistar rats were randomly divided into five groups, the normal control group (A), the methotrexate (MTX) control group (B), the IL-11-pre-treated high-dose group (C), the post-IL-11-treatment high-dose group (D) and the post-IL-11-treatment low-dose group (E). After the intraperitoneal injection of MTX in the groups B-E, the rats were sacrificed at 1, 3, 5 and 7 days. The mortality, morphological and ultrastructural changes of small intestine of each group were observed. The cells were then cultured in vitro, and the MTT method was used to investigate the effects of different concentration of IL-11 on CEM proliferation and also on HDMTX-induced mucositis.

Results: IL-11 could reduce the intestinal histopathological score, increase the height of small intestinal villi, promote the proliferation of intestinal lacunar cells and reduce the mortality rate of rats. The IL-11 pre-treatment group exhibited the best efficacies, demonstrating significant difference with the control group (P<0.01). In addition, the proliferation of CEM was not promoted, indicating that IL-11 could not inhibit HDMTX.

Conclusion: IL-11 could reduce the severity of HDMTX-induced intestinal mucositis, and improve the survival rate of experimental rats, and could be safely used as the adjuvant treatment of HDMTX in childhood leukemia.

Introduction

The high dose methotrexate (HDMTX) chemotherapy had been widely used in the childhood. The HDMTX chemotherapy could not only be effective in preventing the occurrence of extramedullary leukemia, but also improve the disease-free survival of children with acute lymphocytic leukemia. Increasing the amount of methotrexate (MTX) can significantly increase the dru g concentrations in the blood and cerebrospinal fluid, thus enhancing the efficacy, while the side effects were also increasingly prominent. As it is well known that MTX had higher affinities towards the tissues such as the bone marrow, skin and gastrointestinal mucosa due to their higher proliferation rate, shorter proliferation cycle (24-48 hr) and faster regen eration speed, hence, myelosuppression and gastrointestinal mucositis can be considered as the main side effects of MTX. It has been reported that the incidence of mucositis could still be as high as 20-25% despite adequate preparation (1), and even up to 39% after HDMTX chemotherapy (2). The severe mucositis would not only affect the patients' eating, and prolong the hospitalization, but can also cause the bloody diarrhea, sepsis, septic shock, and even death, and as a consequence, can seriously influence the next course of chemotherapy. Currently, there is no effective strategy for the management of HDMTX chemotherapy side effects. How to maximally reduce the post-HDMTX incidence and severity of mucositis, and raise leukemia children's tolerance to HDMTX, had become the most important issue that needed to be solved.

In recent years, researchers had established a variety of MTX-induced mucositis model to reveal the pathological process of MTX-induced mucositis, thus providing the theoretical basis for the clinical treatment. Some studies have shown that a number of growth factors and certain amino acids may have mucosal protective effects through different mechanisms. For example, the hepatocyte growth factor, intestinal TFF3 factor and insulin-like growth factor (IGF-I) etc. can play their roles through the autocrine or paracrine mechanism; the keratinocyte growth factor (KGF) can enhance the DNA repair, thus affecting the proliferation and differentiation of intestinal epithelial stem cells; and the intes tinal transforming growth factor can repress the cell cycle of intestinal lacunar stem cells, thus preventing the differentiation of intestinal epithelial cells in the G1 phase, so that the lacunar stem cells will not be damaged by the cell cycle-specific chemotherapeutic drugs (3-10).

The glutamine (GLN), not only provided the nutritional supports for the epithelium and mucosa, but also could increase the concentration of intracellular MTXPG and enhance anti-metabolic effects of MTX (11, 12). Findings show that the novel cytoprotective agent amifostine can prevent and treat th e radiotherapy and chemotherapy -induced oral and intestinal mucositis (13, 14). However, the mechanisms of HDMTX-induced mucositis had not been elucidated. Also, it has been found that MTX can directly inhibit the DNA synthesis of epithelial cells or accelerate the apoptosis of intestinal crypt cells (15, 16), so that the risk of gut-associated sepsis may be increased (17). In addition, the age and inadequately -prepared chemotherapy might also increase the toxicity of MTX.

The researches about whether the hematopoietic growth factor interleukin 11 (IL-11) had the mucosal protective effects were rare. A few single-center experimental researches have been conducted on the mucositis model or cancer patients who also suffered from the mucositis, and found that IL-11 could reduce the severity and duration of mucositis, thus improving the quality of life in these patients (18-20). However, IL-11 was basically one hematopoietic growth factor derived from the bone marrow stromal cells, which played a major role in the regulation of hematopoiesis. Since, no study has been performed on whether it can promote the proliferation of tumor cells during stimulating the hemocytogenesis, and affect the function of anticancer drugs, in this study; a research was conducted to study this issue.

Materials and Methods

Animals and induction of experimental intestina mucositis

In this study, 95 Wistar rats, weighed 120-150 g, were ran domly divided into five groups: Group A (n=15): the normal control group; Group B (n=20): the MTX control group; Group C (n=20): the high-dose IL-11 (475 μg/kg-1/d-1, Qilu Pharmaceutical Co, Ltd, Jinan, China) treatment before using MTX (Jiangsu Hengrui Medicine Co, Ltd, Lianyungang, China); Group D (n=20): the high-dose IL-11 (475 μg/k g-1/d-1) treatment after using MTX; Group E (n=20): the low-dose IL-11 (150 μg/kg-1/d-1) treatment after using MTX. A total of 95 5week-old Wistar rats (male or female), clean grade, weighed 120-150 g were housed at room temperature (20-22 °C) in 12/12 dark light cycles and 50-55% humidity.

The dose range of HD-MTX was based on a previous study (21), and the recommended dose was 3 g / m2 (100 mg / kg) in terms of body weight. The dose of IL11 referred to the package insert.

The group A was injected normal saline, with 1 ml/per rat from the 1st to 5th day, the group B-E were intraperitoneally injected 1 ml MTX (100 mg/kg) to establish the mucositis model. The Group B was intraperitoneally injected 1 ml MTX on the d0 day; meanwhile, 1 ml saline was subcutaneously injected simultaneously with MTX, as well as 2 days before and after the injection, respectively. The Group C was s ubcutaneously injected high-dose IL-11 2 days before the MTX injection, twice/day × 2 days. The Group D was subcutaneously injected high-dose IL-11 two days after the MTX injection, twice/day × 2 days. The Group E was subcutaneously injected low-dose IL-11 two days after the MTX injection, twice/day × 2 days.

Two rats of the Group B were sacrificed on the 1st, 3rd, 5th and 7th day after the MTX injection, respectively, and 2 rats of the C, D and E group were sacrificed on the 3rd and 5th day after the MTX injection; the time points of the group A were the same as the group B. This study was carried out in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. The animal use protocol has been reviewed and approved by the Institutional Animal Care and Use Committee (IACUC) of Liaocheng People's Hospital.

Hematoxylin and eosin staining

The pro ximal segment of jejunal tissues were tak en for pathological analysis and hemato xylin and eosin (HE) staining. each gro up was randomly selected two slices, and each slice was randomly selected three high -po wer fields, the calculation of histopathological score was in accordance wi th the Howarth et al method (4) for the semiquanti tative analysis. No lesion was recorded as 0 point, the mild lesion was recorded as 1 point, the moderate l esion was recorded as 2 points, and the s evere lesion was recorded as 3 points.

Determination of intestinal villus height, crypt depth

Determination of intestinal villus heigh t, crypt depth and c alculation of villus hei ght/crypt depth ratio was perfo rm ed. For this purpos e, 3 pathological sections of 2 rats of each gro up were co unted using 200 X light microscop e, and 10 villus heights and 10 crypt depths were detected in each slice.

Immunohistoche mical staining

The jejun al tissue paraffin sec tions were dewaxed and hydrated, followed by washing with phosphate buffered saline (PBS) fo r two tim es, 5 min for eac h time. After enzym e closure wi th 3% hydrogen peroxide at room temperature for 5 -10 min, the anti gen retri eval was performed. After washing with PBS fo r 5 min, the norm al goat serum (Fuzho u Maixin Biotechnology Develo pment Co., Ltd., Fuzhou, China) was added for blocking at roo m temperature for 20 min. The excess liquid was removed, and then the primary antibody (Fuzhou M aixin Biotechnology Development Co, L td, Fuzhou, China) was added, followed by incubation at room temperature for 1 h r. After was hing with PBS for 3 times, 2 min for each time, the bioti nylated secondary antibody (Fuzho u Maixin Biotechnology Dev elopment Co, Ltd., Fuzhou, China) was ad ded, followed by incubation at 20-3 7 °C for 20 min. After washing with PBS for 3 times, 2 min for each tim e, SABC was added, followed by incubation at 20-37 °C f or 20 min. After colo ration, counterstain and mounting, the sections w ere observed in Q550CW im age acquisition and analysis system (Leica Scienc e Lab, Berlin, Germ any). The absolute values of positively -stain ed cells tow ards the total sm all-intestinal glandular cells, as well as the ratio of the enti re positive nuclei were counted. The crypt and n uclei of 2 rats were counted with 400-600 nuclei and 10 similar crypts per rat.

Electron microscope

The pro ximal segment of jejunal tissues w ere sampled under the low temperature con ditions to prepare the ultra-thin slice, and then the Lead - Uranium dual-staining electron microscope was used to observe the ultrastructural changes.

Mortality rates

The mortality rates of the experimental animals were investi gated at the 1st, 3rd, 5th and 7th day after the HDMTX injection.

Proliferation of the human T-lymphobl astic leukemia (CEM) cells

The MTT (Sigma -Ald rich Corp., MO, USA) assay was performed to test the impacts of diff erent concentratio ns of IL-11 on proliferation of CEM cells (Institute of Hematology, Chin ese Academy of Medical Scienc es, Tianjin, China) in different tim e periods. CEM cells in the exponential growth phas e (with th e cell concentration at 3.0 ×105 /ml) w ere collected. The final conc entrations of IL-11 were 9.375, 18.75, 37.5, 75, 150, 300, 600, and 1200×10-3 μg/ml, respectively. One hundred microliter of various IL -11 co ncentrations to gether with 100 μl cell suspensions were added in to the 96-well flat-botto m culture plates. Three repeating w ells were set for each sample group (th e experimental group, the c ell control gro up and the control gro up) , and the samples were cul tured at 37 ° C, 5% CO2 and saturated humidity for 24, 48 and 7 2 hr. Ten microliter MTT reagent (5 mg/ml) w as added into each well 4 hr b efo re terminating th e culture. Afterwards, the s amples were centrifug ed at 2000 r/min for 10 min. Th e supern atant w as then discarded, and 150 μl DM SO (Bei jing Asia-Pacific Chemical Technolo gy Co, Ltd, Bei jing, China) was added to each w ell, followed by the thoro ugh shaking to completely dissolve the fo rm azan particles. The abso rbance was then measured with ELI SA assay (BS -1101, Nan jing Tiede Exp erimental Equipment Co, Ltd, Nan jin g, China) at 5 70 nm as the detection wavelength, and 630 nm as the referenc e wavelength, th e A570-630 was recorded as th e final absorbance value.

Impacts of IL-11 on the anti-tumor effects of MTX

The CEM cells in the exponential growth phas e (with the c ell concentration as 3.0×105/ml) were tak en. In the A group (MTX co ntrol group), the final concentratio ns of MTX were 6, 12.5, 25, 50, 1 00, and 200×10-3 μg/ml; but, in the B group (IL-11 + MT X groups), the final concentrations of IL -11 were 75, 150, 30 0, and 60 0×10-3 μg/ml, while the final concentrations of MTX were the same as the group A. The IL -11 co ntrol group an d the control group w ere also set simultaneously. Then, IL -11 and MTX would act to gether o n the CEM c ells for 24 and 48 hr, respectively. The detec tion method was with ELISA assay. Subsequently, the inhibi tion rates of the two gro ups were compared. The inhibitio n rate (%)= (absorbance of the cell control group - absorbance of the experim ental group)/absorbanc e of the cell control group × 100%.

Statistical methods

The SPSS 12.0 window statistical software w as used to analyze the data, and the χ2 test was used for the com parison of rates. In addition, t test was used to compare the m ean values of two samples. Bilateral P<0.05 was co nsidered as the s tatistically significant differences.

Results

Incidence and mortality

The A group exhibited norm al eating activities, without di arrhea and death; while, the rats of B~E gro up exhibited different degrees of hair loosening, back arching, diarrhea, activity and eati ng reduction two days after the MTX injec tion. The diarrhea was more s evere on the 3rd day, while the eating was increased fro m the 5th d ay, and the diarrhea gradually stopped on th e 7th day. The anatomical specimen rev ealed that MTX injection group exhibi ted severe retention of gastrointestinal liquid, flatulence, intestin al vascular congestion and mesenteric adhesions on the 3rd day, esp ecially in th e B group. T he mortality rate of the B group was higher th an o ther groups ( up to 50%), while th at of the C group was the lowest with only 15%, indicating that there was a significant difference betw een the 2 groups (P<0. 01). The mortality rate of D group was also 20%, which exhibited significant diff erence with the B group (P<0.05). The com parison among the C, D and E gro ups exhibited no significant differenc e (P>0.05). Although the comparison betwe en the E and B groups exhibited no statistic ally significant differenc e (χ2=1.08, P>0.05), the mortality rate was still lower than the MTX control group.

Morphological changes

The A group exhibited no significant pathological changes in the intestinal tis sues. The small intestine villi were slender, neatly arranged, and the brush-like border was clear. Also, the epithelial cells were intact, and the goblet cells were plenty. The B~E group exhibited different degrees of pathological changes in the intestinal tissues, among which the situation of the B group was more severe on the 3rd day. The intestinal villi were significantly shorter, flatter, atrophic, and even completely ablated. The lacunar morphology of small intestine was lost, and the goblet cells disappeared; moreover, the villous stroma exhibited congestion, with the infiltration of a large number of inflammatory cells, lacunar abscesses. Also, the cell proliferation was extremely reduced. The pathological changes were significantly reduced on the 5th day, the villi were increased, and the number of goblet cells was increased. The pathological changes of the C, D and E group, especially the C group (with the lightest pathological changes and the lowest pathological score) on the 3rd day were significantly lighter than the B group, exhibiting significant differences when compared with the B, C and D group (P<0.05). The villus height and the lacunar depth were greater than those of the B, D and E group at the same time point. The results of each group were shown in Table 1, 2 and 3. Also, the Figures 1, 2 and 3 were shown in the appendix.

As it could be seen fro m the Tables, the villus heights and crypts depths of the C, D and E grou p were greater than those of the B gro up at the same time. The com parison between the C and B Gro up, on the third day showed that the difference w as extremely significant (t=5.32, P<0.01).

The comp arison betw een the C and E group also showed that the difference was significant (P<0.05).

Results of PCNA immunohistochemical staining

Three days after the IL-11 treatment, th e intestinal lacunar cells began to si gnificantly proliferate and proliferated excessively on the 5th day (P<0.05).

The ratio of PCNA positive staini ng nuclei, as well as the absolute num bers of positive s taining nuclei inside each crypt were significantly higher than the control group (P<0.05).

Discussion

It is well known that IL-11 can promote the development and maturation of megakaryocytes. Also, it had been widely used in the treatment of chemotherapy-caused secondary thrombocytopenia. In recent years, it was found that IL-11 also has immunomodulatory, and anti-inflammatory roles as well as epithelial cell-regulatory effects (22). Based on this theory, in this study we established rat intestinal mucositis model, aiming to verify the anti - inflammatory mechanisms and the mucosal protective effects of IL-11 through different doses and different dosing time points. According to the results of this study, HDMTX-induced intestinal mucositis was an inflammatory process of acute injury. Different dosing time points and different doses of IL-11 could reduce the pathological scores of mucositis, with the villus length and lacunar depth significantly increased in comparison with the control group. The proliferation of intestinal lacunar nuclei was accelerated, and the mortality rate was declined, which showed a dose-dependent relationship. In this study, the pathological changes of mucositis after the HDMTX injection were aggravated, and the incidence of mucositis was significantly higher than other reports in the literature (1), which was deduced that it can partly because the eating and drinking were severely affected after the HDMTX injection. This situation was equivalent to the situations of non-hydration and non-alkalization.

IL-11 was a hematopoietic growth factor derived from the bone marrow stromal cells, and played a significant role in the regulation of hematopoiesis, while the mechanisms that how it affected the epithelial cells, thus playing the regulatory roles towards the epithelial cells and the anti-inflammatory effects were still unclear. Through the experiment, we found that the IL-11 pretreatment group and the high-dose group exhibited the faster recovery speed of intestinal mucosa, and the probable reasons might be related with that IL-11 could accelerate the mitosis of intestinal lacunar cells. This feature, which was basically consistent with the previous report, was verified by the PCNA immunohistochemical staining (18). PCNA was mainly synthesized in the G1 and S phase of cell cycle, playing important roles in the cellular proliferation. It has been previously reported that IL-11-accelerated mucosal recovery was because it speeded the proliferation of gastrointestinal mucosal cells and gastrointestinal wall muscle cells (19). It has also been demonstrated that IL-11 might reduce the expressions of pro-inflammatory factors, such as TNF-αs (20, 22). Findings have shown that transient cell cycle arrest is a possible mechanism by which rhIL-11 may protect intestinal epithelial cells from damage induced by chemotherapy or radiation therapy (23). In brief, in-depth studies are still needed to reveal the anti-infective mechanisms of IL-11. The results of in vivo studies on rat model of mucositis indicated that IL-11 might act through directly penetrating the epithelial cells and tissues.

In this study, the human T-lymphoblastic leukemia cell line (CEM) was used as the target, and morphological observation was also used to investigate the impacts of different -concentration of IL-11 towards the CEM proliferation and the anti-tumor effects of MTX. Findings showed that IL-11 could not promote the proliferation of CEM cells, thus it could be safely used for the bone marrow suppression after the HDMTX chemotherapy.

Conclusion

IL-11 could reduce the severity of HDMTX-induced intestinal mucositis, and improve the survival rate of experimental rats. But, IL-11 could not promote the proliferation of CEM cells. IL-11 could be safely used as the adjuvant treatment of HDMTX in childhood leukemia.

Acknowledgment

The results described in this paper were part of student thesis. Special acknowledgements should be given to the teachers in the Animal Laboratory , School of Medicine of Shandong University, and the Shandong Provincial Institute of Basic Medical research. Project No.: 2013-03-02-35-03, Shandong Provincial Health Bureau.

Conflict of interest

All authors have no conflict of interest regarding this paper.

Sidebar

*Please cite this article as:

Han Y, Zhu Y, Wang J, Han Y, Qin D, Yan g Q, Sun X, Chen L. Repairing effects of interleukin 11 (IL-11) towards high dose methotrexateinduced rat small intestinal mucositis and its impacts on T-lymphoblastic leukemia cell line. Iran J Basic Med Sci 2016; 19:734-740.

References

References

1. Chabner BA, Devita VT. Anticancer drugs in cancer. Hellman S, Rosenberg SA. editors. Principles and Practice of Oncology. 4th ed. 1995.p. 325-417.

2. Kapoor G, Sinha R, Abedin S. Experience with high dose methotrexate therapy in childhood acute lymphoblastic leukemia in a tertiary care cancer centre of a developing country. Pediatr Blood Cancer 2012; 59:448-453.

3. Xian CJ, Corper R, Howarth GS, Read LC, Kallincos NC. Incread expression of HGF and c-met in rat small intestinal during recovery from methotrexate-induced mucositis. Br J Cancer 2000; 82:945-952.

4. Howarth GS, Cool TC, Bourne AJ, Ballard FJ, Read LC. Insuline-like growth factor-I (IGF-I) stimulates regrowth of the damaged intestine in rats, when administered following, but not concurrent with methotrexate. Growth Factors 1998; 15:279-292.

5. Xian CJ, Howarth GS, Mardell CE, Cool JC, Familari M, Read LC, et al. Temporal changes in TFF3 expression and jejunal morphology during methotrexate-induced damage and repair. Am J Physiol 1999; 277:G785-795.

6. Zheng C, Cotrim AP, Sunshine AN, Sugito T, Liu L, Sowers A, et al. Prevention of radiation-induced oral mucositis after adenoviral vector-mediated transfer of the keratinocyte growth factor cDNA to mouse submandibular glands. Clin Cancer Res 2009; 15:4641-4648.

7. Ceccarelli S, Romano F, Angeloni A, Marchese C. Potential dual role of KGF/K GFR as a target option in novel therapeutic strategies for the treatment of cancers and mucosal damages. Export Opin Ther Targets 2012; 16:377-393.

8. Ben-Lulu S, Pollak Y, Mogilner J, Bejar J, G Coran A, Sukhotnik I. Dietary transforming growth factor-beta 2 (TGF-β2) supplementation reduces methotrexate - induced intestinal mucosal injury in a rat. PLoS One 2012; 7:e45221.

9. Raber-Durlacher JE, von Bültzingslöwen I, Logan RM, Bowen J, Al-Azri AR, Everaus H, et al. Systematic review of cytokines and growth factors for the management of oral mucositis in cancer patients. Suport Care Cancer 2013; 21:343-355.

10. Worthington HV, Clarkson JE, Bryan G, Furness S, Glenny AM, Littlewood A, et al. Interventions for preventing oral mucositis for patients with cancer receiving treatment. Cochrane Database Syst Rev 2011; CD000978.

11. Sukhotnik I, Pollak Y, Coran AG, Pilatov J, Bejar J, Mogilner JG, et al. Glutamine attenuates the inhibitory effect of methotrexate on TLR signaling during intestinal chemotherapy-induced mucositis in a rat. Nutr Metab (Lond) 2014; 11:17.

12. Sukhotnik I, Mogilner JG, Karry R, Shamian B, Lurie M, Kokhanovsky N, et al. Effect of oral glutamine on enterocyte turnover during methotrexate-induced mucositis in rats. Digestion 2009; 79:5-13.

13. Gu J, Zhu S, Li X, Wu H, Li Y, Hua F. Effect of amifostine in head and neck cancer patients treated with radiotherapy: a systematic review and meta-analysis based on randomized controlled trials. PLoS One 2014; 9:e95968.

14. Chen C, Tian L, Zhang M, Sun Q, Zhang X, Li X, et al. Protective effect of amifostine on high-dose methotrexate-induced small intestinal mucositis in mice. Dig Dis Sci 2013; 58:3134-3143.

15. Morón-Medina A, Viera N, de Morales TR, Alcocer S, Bohorquez D. Methotrexate as inducer of proinflammatory cytokines by ep ithelial cells. Invest Clin 2014; 55:15-22.

16. Gibson RJ, Keefe DM, Thompson FM, Clarke JM, Goland GJ, Cummins AG. Effect of interleukin -11 on ameliorating intestinal damage after methotrexate treament of breast cancer in rats. Dig Dis Sci 2002; 47:2751-2757.

17. Yang L, Hu X, Xu L. Impact of methylenetetra-hydrofolate reductase (MTHFR) polymorphisms on methotrexate-induced toxicities in acute lymphoblastic leukemia: a meta-analysis. Tumour Biol 2012; 33:1445-1454.

18. Du XX, Doerschuk CM, Orazi A, Williams DA. A bone marrow stromal-derived growth factor, interleukin-11, stimulates recovery of small intestinal mucosal cells after cytoablative therapy. Blood 1994; 83:33-37.

19. Wen CY, Ito M, Matsuu M, Fukuda E, Shichijo K, Nakashima M, et al. Mechanism of the antiulcerogenic effect of IL-11 on acetic acid-induced gastric ulcer in rats. Life Sci 2002; 70:2997-3005.

20. Sonis ST, Person RL, Edward LJ, Lucey CA, Wang L, Mason L, et al. Defining mechanisms of action of interleukin-11 on the progression of radiation-induced oral mucositis in hamsters. Oral Oncol 2000; 36:373381.

21. Chinese Pediatric Society, Chinese Medical Association. Diagnosis and treatment of acute lymphoblastic leukemia of childhood (The Fourth revised draft). Chin J Pediatr 2014; 52:641-644.

22. Schwertschlag US, Trepicchio WL, Dykstra KH, Keith JC, Turner KJ, Dorner AJ. Hematopoietic, immunomodulatory and epithelial effect of interleukin-11. Leukemia 1999; 13:1307-1315.

23. Peterson RL, Bozza MM, Dorner AJ. Interleukin-11 induces intestinal epithelial cell growth arrest through effects on retinoblastoma protein phosphorylation. Am J Pathol 1996; 149:895-902.