Supplementary MaterialsAdditional file 1: Table S1. in human intestine and aberrantly expressed in several types of tumor. However, studies on CRIP1 are limited and its role on tumor development and progression remains controversial and elusive. Methods Immunohistochemistry was performed to evaluate the expression of CRIP1 in paired normal and colorectal tumor specimens, as well as colorectal cell lines. GNE-7915 inhibitor Functional assays, such as CCK8, TUNEL assay and in vivo tumor growth assay, were used to detect the proliferation, apoptosis and response to 5-FU of CRIP1. Western blot was used to analyze Fas-mediated pathway induced by CRIP1. Rescue experiments were performed to evaluate the essential role of CRIP1 for Fas-mediated apoptosis. Results We demonstrated that CRIP1 is overexpressed in CRC tissues compared with adjacent normal mucosa. CRIP1 could dramatically recover the 5-Fluorouracil (5-FU) inhibited CRC cell proliferation in vitro and stimulate the tumor formation of CRC in vivo, probably through inhibiting CRC cell apoptosis. Moreover, CRIP1 also dramatically recovered the 5-Fluorouracil (5-FU) induced tumor cell apoptosis in vitroFurther study demonstrated that CRIP1 down-regulated the expression of Fas protein and proteins related to Fas-mediated apoptosis. CRIP1 could interact with Fas protein and stimulate its ubiquitination and degradation. In addition, a negative correlation was detected between the expression of CRIP1 and Fas protein in most of the clinical human CRC samples. Conclusion The GNE-7915 inhibitor current research reveals a vital role of CRIP1 in CRC progression, which provide a novel target for clinical drug resistance of colorectal cancer and GNE-7915 inhibitor undoubtedly contributing to the therapeutic strategies in CRC. Electronic supplementary material The online version of this article (10.1186/s13046-019-1117-z) contains supplementary material, which is available to authorized users. strong class=”kwd-title” Keywords: Cysteine-rich intestinal protein 1, Colorectal cancer, Apoptosis, Chemoresistant, FAS Introduction Colorectal cancer (CRC) ranks third in terms of incidence but second in terms of mortality [1]. Although numerous efforts have been made to improve diagnostic and therapeutic strategies for CRC patients, survival rate GNE-7915 inhibitor of patients with advanced colorectal cancer remains low within five years [2]. Most patients still die due to the therapeutic resistance of CRC to conventional anti-cancer drugs and recurrence after resection. The internationally accepted first-line treatment for metastatic colorectal cancer (mCRC) is FOLFOX or FOLFIRI treatment regimen consists of 5-fluorouracil (5-FU)/leucovorin (LV) plus oxaliplatin or irinotecan [3]. 5-FU, the cornerstone of CRC chemotherapy, could stop the DNA production of tumor cells through blocking the action of thymidylate synthase. Therefore, it is urgent to uncover vital molecular mechanisms underlying CRC progression and drug resistance, which helps to figure out novel diagnostic and prognostic biomarkers. Cysteine-rich intestinal protein1 (CRIP1) is a member of LIM/double-zinc finger protein family predominantly expressed in the intestine, which is first verified important for zinc transport and absorption [4]. Besides intestine, CRIP1 is subsequently recognized in other organs including Hif3a colon, lung, spleen, thymus and head in transgenic mice [5]. CRIP1 was further recognized in immune cells in cells of rats, suggested the involvement of this protein in host defense [6]. Aberrant manifestation of CRIP1 was also described in several tumor types including prostate malignancy, pancreatic caner, cervical malignancy, breast tumor, osteosarcoma, gastric malignancy, and thyroid malignancy [7C13]. However, related studies are very limited and the part of CRIP1 is definitely controversial in different tumor types. Large manifestation of CRIP1 is definitely correlated with a favorable prognosis in osteosarcoma and breast tumor [10, 11]. In contrast, high CRIP1 manifestation was confirmed like a novel and self-employed prognostic element for poor prognosis in gastric malignancy individuals [12]. Knockdown of CRIP1 inhibited the proliferation GNE-7915 inhibitor of thyroid carcinoma cells through inducing G1 arrest and apoptosis, while silencing of CRIP1 significantly elevated the proliferation of T47D and BT474 breast tumor cells via reducing the phosphorylation of cdc2. In addition, knockdown of CRIP1 improved breast tumor cell invasion in vitro [10]. CRIP1 was also identified as a bone specific breast tumor metastasis gene [14, 15]. Except thoes practical stdudies mentioned above, mechanisms under CRIP1 mediated tumor devlopment and progression are mainly unfamiliar. As few data is definitely available on CRIP1 in colorectal malignancy, this study was carried out to systematically characterize the manifestation and functions of CRIP1 during CRC development and progression. Our results suggest that CRIP1.