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Although improved treatment could inhibit progression of gastric cancer (GC), the recurrence and metastasis remain challenging issues. Methyltransferase like 13 (METTL13) has been implicated in most human cancers, but its function and mechanism in GC remain elusive. In the present study, we evaluated its expression in GC samples and found it was aberrantly overexpressed in cancer tissues than that in normal stomach tissues. High expression of METTL13 was closely associated with age, tumor size and T classification. Biological experiments showed that silencing METTL13 suppressed gastric cancer cell proliferation and metastasis in vivo and vitro, whereas opposite effects were observed upon METTL13 overexpression. Further mechanistic explorations revealed that METTL13 regulated the expression of HN1L (Hematological and neurological expressed 1-like), which is reported to be an oncogene in various cancers. Knockdown of HN1L dampened gastric cancer cell growth induced by METTL13. Eukaryotic translation elongation factor-1A (eEF1A), the present sole methylation substrate of METTL13, was involved in the regulation of HN1L by METTL13 in a K55 methylation independent manner. In addition, we also found HN1L could facilitate METTL13 expression in GC cells consistent with a previous report in hepatocellular carcinoma. Thus, these findings demonstrate a METTL13/eEF1A/HN1L positive feedback circuit promoting gastric cancer development and metastasis. It will help develop promising diagnostic and therapeutic targets for this disease.

Gastric cancer (GC) has always been a great threat to human health due to its aggressiveness and lethality. Anlotinib, a novel multi-target tyrosine kinase inhibitor (TKI), has been certified its anti-tumor effects on various tumors. Nonetheless, there are few studies on applying anlotinib as a treatment for GC. The underlying mechanism of acquired resistance during anlotinib administration remains unclear.We investigated the toxicologic effects of anlotinib on GC cells through CCK8, colony-forming, and flow cytometry assays in vitro and xenograft models in vivo. Anlotinib-resistant GC cells, AGS-R and MGC803-R, were generated and characterized by cell proliferation and apoptosis assays. The signaling pathways involved in anlotinib resistance were probed using Cignal™ Finder 10-Pathway Reporter Array. Western blot and dual-luciferase reporter assays were performed to confirm the relationships. The TGF-β inhibitor LY364947 was introduced to demonstrate the importance of TGF-β signaling in anlotinib resistance via a series of functional assays.Anlotinib suppressed cell growth and induced apoptosis in vitro and inhibited tumorigenesis and metastasis in vivo, while its anti-tumor effects were impaired in anlotinib-resistant cells. The results of dual-luciferase reporter assays and western blot indicated TGF-β signaling was activated in anlotinib-resistant GC cells. LY364947 combined with Anlotinib exerted a better antineoplastic effect than monotherapy and considerably reversed the anlotinib resistance in GC.Our findings suggested that TGF-β signaling may take a significant part in anlotinib resistance in GC. The suppression of TGF-β signaling may be a possible and promising approach for the GC oncotherapy when combined with anlotinib.

Patients with DNA mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) cancers are prone to response to programmed cell death-1 (PD-1) checkpoint inhibitors. Therefore, we explored the efficacy and safety of a PD-1 checkpoint inhibitor camrelizumab in advanced or metastatic solid tumour with dMMR/MSI-H. Patients with dMMR/MSI-H advanced or metastatic solid tumours who had received at least one line of prior systemic chemotherapy were recruited. Camrelizumab was given intravenously 200 mg every 2-week treatment cycle. The primary endpoint was objective response rate according to Response Evaluation Criteria in Solid Tumours v1.1. Twelve patients were enrolled. As data cutoff, eight patients (66.7%, 95% CI 34.9–90.1) achieved objective response. Disease control rate reached 100% (95% CI 73.5–100). Progression-free survival rate at 12 months was 83.3% (95% CI 48.2–95.6), and overall survival rate at 12 months was 90% (95% CI 47.3–98.5). The most common treatment-related adverse events were reactive cutaneous capillary endothelial proliferation (100%), increased alanine aminotransferase (41.7%), and increased aspartate aminotransferase (41.7%). Camrelizumab provided durable objective response and disease control in pre-treated patients with dMMR/MSI-H advanced or metastatic solid tumour, being a promising treatment option for these patients.

Sorafenib is the standard first-line drug for the treatment of advanced hepatocellular carcinoma (HCC), however, its therapeutic efficacy is not satisfactory due to primary or secondary resistance of HCC cells. In the present study, we identified Metaxin 1 (MTX1) as a new regulator of sorafenib resistance in HCC through genome-scale CRISPR activation (CRISPRa) screening. We found that MTX1 was frequently upregulated in HCC tissues and overexpression of MTX1 promoted HCC cell proliferation in vitro and in vivo. As well, MTX1 overexpression increased cell growth rate and decreased cell apoptosis upon sorafenib treatment. Consistently, the resistance induced by MTX1 was also observed in subcutaneous xenograft tumor model. Clinically, high expression of MTX1 was closely related with poor outcomes in HCC patients who received sorafenib treatment. Mechanistically, overexpression of MTX1 could promote HCC cell autophagy via interacting with and inhibiting CDGSH iron sulfur domain 1 (CISD1), an autophagy negative regulator. Taken together, our findings suggest that MTX1 is upregulated in HCC and contributes to sorafenib resistance via a possible mechanism involving CISD1 mediated autophagy.

e15140 Background: PD-1 checkpoint inhibitor has been shown a significant effect in patients (pts) with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) solid tumor. Herein, we assessed the efficacy and safety of camrelizumab, a PD-1 checkpoint inhibitor, in advanced or metastatic solid tumor pts with MSI-H/dMMR. Methods: Pts with MSI-H/dMMR solid tumor who had received at least one line of prior systemic chemotherapy were recruited in this single-arm exploratory study. Pts received camrelizumab (200mg, ivd, D1/2W) until disease progression or intolerable toxicity. Response was assessed every 8 weeks. The primary endpoint was objective response rate (ORR) according to RECIST v1.1 criteria. This study was registered at Chinese Clinical Trial Registry, ChiCTR-OIC-17013249. Results: From November 2017 to February 27, 2019, 12 eligible pts were recruited, which covered 9 cancer types. The median age was 58 (range 27-72) years; male/female was 58.3/41.7%. 11 pts were confirmed as MSI-H status, and 1 patient as d-MMR status. All pts were included in efficacy and safety analysis. 2 pts achieved complete response (CR), 6 pts partial response (PR), 4 pts stable disease (SD), yielding the ORR of 66.7% (95% CI: 34.9-90.1), and the disease control rate of 100% (95% CI 73.5-100) at best. What’s more, cancer types of CR pts covered rectal cancer and bladder cancer (1 patient each); PR pts included colon cancer, liver cancer, endometrial cancer, ureteric cancer, intrahepatic cholangiocarcinoma, and small intestine cancer (1 patient each); SD pts contained 3 colon cancer pts and 1 retroperitoneal leiomyosarcoma patient. The overall incidence of adverse incidences (AEs) was 100%. The incidence of Grade ≥3 AEs was 58.3%, which mainly included anemia (16.7%), increased γ-transglutaminase (16.7%), increased alkaline phosphatase (16.7%), increased blood bilirubin (16.7%). As of Oct 30, 2019, 11 pts were still on study medication. Conclusions: Camrelizumab resulted in encouraging objective response and tolerable toxicity in MSI-H/dMMR advanced or metastatic solid tumor. The survival benefits will be further observed. Clinical trial information: ChiCTR-OIC-17013249 .

Spermatogenesis is composed of three distinctive phases, which include self-renewal of spermatogonia via mitosis, spermatocytes undergoing meiosis I/II and post-meiotic development of haploid spermatids via spermiogenesis. Spermatogenesis also involves condensation of chromatin in the spermatid head before transformation of spermatids to spermatozoa. Epigenetic regulation refers to changes of heritably cellular and physiological traits not caused by modifications in the DNA sequences of the chromatin such as mutations. Major advances have been made in the epigenetic regulation of spermatogenesis. In this review, we address the roles and mechanisms of epigenetic regulators, with a focus on the role of microRNAs and DNA methylation during mitosis, meiosis and spermiogenesis. We also highlight issues that deserve attention for further investigation on the epigenetic regulation of spermatogenesis. More importantly, a thorough understanding of the epigenetic regulation in spermatogenesis will provide insightful information into the etiology of some unexplained infertility, offering new approaches for the treatment of male infertility.

Spermatogenesis is a special process by which spermatogonial stem cells (SSCs) divide and differentiate to male gametes called mature spermatozoa. SSCs are the unique cells because they are adult stem cells that transmit genetic information to subsequent generations. Accumulating evidence has demonstrated that SSCs can be reprogrammed to acquire pluripotency to become embryonic stem-like cells that differentiate into all cell lineages of the three germ layers, highlighting potential important applications of SSCs for regenerative medicine. Recent studies from peers and us have made great achievements on the characterization, isolation, and culture of mouse and human SSCs, which could lead to better understanding the biology of SSCs and the applications of SSCs in both reproductive and regenerative medicine. In this review, we first compared the cell identity and biochemical phenotypes between mouse SSCs and human SSCs. Notably, the cell types of mouse and human SSCs are distinct, and human SSCs share some but not all phenotypes with mouse SSCs. The approaches for isolating SSCs as well as short- and long-term culture of mouse SSCs and short-period culture of human SSCs were also discussed. We further addressed the new advances on the self-renewal of SSCs with an aim to establish the long-term culture of human SSCs which has not yet been achieved. J. Cell. Physiol. 229: 407–413, 2014. © 2013 Wiley Periodicals, Inc.

Spermatogonial stem cells (SSCs) can differentiate into spermatids, reflecting that they could be used in reproductive medicine for treating male infertility. SSCs are able to become embryonic stem-like cells with the potentials of differentiating into numerous cell types of the three germ layers and they can transdifferentiate to mature and functional cells of other lineages, highlighting significant applications of human SSCs for treating human diseases. However, human SSCs are very rare and a long-term culture system of human SSCs has not yet established. This aim of study was to isolate, identify and culture human SSCs for a long period. We isolated GPR125-positive spermatogonia with high purity and viability from adult human testicular tissues utilizing the two-step enzymatic digestion and magnetic-activated cell sorting with antibody against GPR125. These freshly isolated cells expressed a number of markers for SSCs, including GPR125, PLZF, GFRA1, RET, THY1, UCHL1 and MAGEA4, but not the hallmarks for spermatocytes and spermatozoa, e.g. SYCP1, SYCP3, PRM1, and TNP1. The isolated human SSCs could be cultured for two months with a significant increase of cell number with the defined medium containing growth factors and hydrogel. Notably, the expression of numerous SSC markers was maintained during the cultivation of human SSCs. Furthermore, SMAD3 and AKT phosphorylation was enhanced during the culture of human SSCs. Collectively, these results suggest that human SSCs can be cultivated for a long period and expanded whilst retaining an undifferentiated status via the activation of SMAD3 and AKT pathways. This study could provide sufficient cells of SSCs for their basic research and clinic applications in reproductive and regenerative medicine.

Stem cells, by definition, are the primitive cells that have the potential of both self-renewal and differentiation into a number of mature and functional cells, and thus they have great applications in cell therapy and tissue engineering for regenerative medicine. Bone morphogenetic protein 6 (BMP6) belongs to transforming growth factor β(TGF-β) superfamily. The fate determinations of stem cells require complex regulatory networks that involve BMP6 signaling pathway. Recent studies have demonstrated that BMP6 plays crucial roles in controlling the self-renewal and differentiation of stem cells. In this review, we address the expression, function and regulation of BMP6 in various kinds of stem cells, with focus on mesenchymal stem cells (MSCs), germline stem cells (GSCs), hematopoietic stem cells (HSCs), and neural stem cells (NSCs). Notably, there are distinct effects of BMP6 on promoting self-renewal and differentiation of these stem cells. We also discuss the involement of BMP6 in diseases, including leukemia, astrocytic glioma, and Alzheimer's disease, and the therapy of these diseases via gene targeting. We further highlight certain issues for further investigation on the regulation and function of BMP6 in stem cells. Significantly, a thorough understanding of BMP6 regulation on a variety of adult stem cells could make them feasible for applications in both regenerative and reproductive medicine, and it would shed novel insights into the etiology of the diseases and offer new targets for drug design to treat these disorders.

Sertoli cell plays critical roles in regulating testis development and spermatogenesis. Any change in the number or biological functions of Sertoli cells can affect the normal formation of spermatozoa. However, the roles and molecular mechanisms of factors in controlling the fate determinations of human Sertoli cells and underlying male infertility remain unknown. Here we have for the first time explored the function and signaling pathway of BMP4 in regulating adult human Sertoli cells and their association with non-obstructive azoospermia (NOA) patients. Immunocytochemistry and immunohistochemistry revealed that BMP4 and its multiple receptors were present in human Sertoli cells. Cell proliferation and BrdU incorporation assays showed that BMP4 promoted DNA synthesis and proliferation of Sertoli cells. In contrast, BMP4 antagonist noggin and BMP4 knockdown reduced the division of Sertoli cells. Moreover, BMP4 knockdown inhibited the synthesis of FGF2, SCF, zonula occludens 1, and claudin 11 but enhanced p27kip1 transcription. BMP4 activated Smad1/5 phosphorylation and upregulated ID2 and ID3 transcription, whereas noggin counteracted these increases. Significantly, tissue arrays disclosed that overexpression of BMP4 may be associated with Sertoli cell-only syndrome and maturation arrest in spermatogonia or spermatocytes. BMP4 was identified as the first autocrine factor that regulates the proliferation and protein synthesis of human Sertoli cells via Smad1/5 and ID2/3 and its abnormality is associated with human non-obstructive azoospermia patients. This study thus provides novel insights into molecular mechanism underlying adult human Sertoli cell growth and offers new targets for gene therapy of male infertility.

Background Sertoli cells play key roles in regulating spermatogenesis and testis development by providing structural and nutritional supports. Recent studies demonstrate that Sertoli cells can be converted into functional neural stem cells. Adult Sertoli cells have previously been considered the terminally differentiated cells with a fixed and unmodifiable population after puberty. However, this concept has been challenged. Since the number of adult human Sertoli cells is limited, it is essential to culture these cells for a long period and expand them to obtain sufficient cells for their basic research and clinic applications. Nevertheless, the studies on human Sertoli cells are restricted, because it is difficult to get access to human testis tissues. Results Here we isolated adult human Sertoli cells with a high purity and viability from obstructive azoospermia patients with normal spermatogenesis. Adult human Sertoli cells were cultured with DMEM/F12 and fetal bovine serum for 2 months, and they could be expanded with a 59,049-fold increase of cell numbers. Morphology, phenotypic characteristics, and the signaling pathways of adult human Sertoli cells from different passages were compared. Significantly, adult human Sertoli cells assumed similar morphological features, stable global gene expression profiles and numerous proteins, and activation of AKT and SMAD1/5 during long-period culture. Conclusions This study demonstrates that adult human Sertoli cells can be cultured for a long period and expanded with remarkable increase of cell numbers whilst maintaining their primary morphology, phenotype and signaling pathways. This study could provide adequate human Sertoli cells for reproductive and regenerative medicine. Electronic supplementary material The online version of this article (doi:10.1186/s12964-015-0101-2) contains supplementary material, which is available to authorized users.

Human spermatogenic cells have not yet been isolated and notably, their global miRNA profiles remain unknown. Here we have effectively isolated human spermatogonia, pachytene spermatocytes and round spermatids using STA-PUT velocity sedimentation. RT-PCR, immunocytochemistry and meiosis spread assays revealed that the purities of isolated human spermatogonia, pachytene spermatocytes and round spermatids were 90% and the viability of these isolated cells was over 98%. MiRNA microarrays showed distinct global miRNA profiles among human spermatogonia, pachytene spermatocytes and round spermatids. Thirty-two miRNAs were significantly up-regulated whereas 78 miRNAs were down-regulated between human spermatogonia and pachytene spermatocytes, suggesting that these miRNAs are involved in the meiosis and mitosis, respectively. In total, 144 miRNAs were significantly up-regulated while 29 miRNAs were down-regulated between pachytene spermatocytes and round spermatids, reflecting potential roles of these miRNAs in mediating spermiogenesis. A number of novel binding targets of miRNAs were further identified using various softwares and verified by real-time PCR. Our ability of isolating human spermatogonia, pachytene spermatocytes and round spermatids and unveiling their distinct global miRNA signatures and novel targets could provide novel small RNA regulatory mechanisms mediating three phases of human spermatogenesis and offer new targets for the treatment of male infertility.

Parkinson's disease (PD) is a common neurodegenerative syndrome characterized by loss of midbrain dopaminergic (DA) neurons. Generation of functional dopaminergic (DA) neurons is of unusual significance for treating Parkinson's disease (PD). However, direct conversion of spermatogonial stem cells (SSCs) to functional DA neurons without being reprogrammed to a pluripotent status has not been achieved. Here, we report an efficient approach to obtain morphological, phenotypic, and functional DA neurons from SSCs using a specific combination of olfactory ensheathing cell-conditioned medium (OECCM) and several defined growth factors (DGF). By following the current protocol, direct conversion of SSCs (both SSC line and primary SSCs) to neural cells and DA neurons was demonstrated by expression of numerous phenotypic genes and proteins for neural cells, as well as cell morphological features. More significantly, SSCs-derived DA neurons acquired neuronal functional properties such as synapse formation, electrophysiology activity, and dopamine secretion. Furthermore, PI3K/Akt pathway and p21/Nolz1 cascades were activated whereas Smurf2 was inactivated, leading to cell cycle exit during the conversion of SSCs into DA neurons. Collectively, this study could provide sufficient neural cells from SSCs for applications in the treatment of PD and offers novel insights into mechanisms underlying neural system development from the line of germ cells.

Spermatogenesis is a complex process by which spermatogonial stem cells (SSCs) self-renew and differentiate into spermatozoa under the elaborate coordination of testicular microenvironment, namely, niche. Sertoli cells, which locate around male germ cells, are the most critical component of the niche. Significant progress has recently been made by peers and us on uncovering the effects of Sertoli cells on regulating fate determinations of SSCs. Here we addressed the roles and regulation of Sertoli cells in normal and abnormal spermatogenesis. Specifically, we summarized the biological characteristics of Sertoli cells, and we emphasized the roles of Sertoli cells in mediating the self-renewal, differentiation, apoptosis, de-differentiation, and trans-differentiation of SSCs. The association between abnormal function of Sertoli cells and impaired spermatogenesis was discussed. Finally, we highlighted several issues to be addressed for further investigation on the effects and mechanisms of Sertoli cells in spermatogenesis. Since Sertoli cells are the key supportive cells for SSCs and they are very receptive to modification, a better understanding of the roles and regulation of Sertoli cells in SSC biology and spermatogenesis would make it feasible to identify novel targets for gene therapy of male infertility as well as seek more efficient and safer strategies for male contraception.

Infertility is a major and largely incurable disease caused by disruption and loss of germ cells. It affects 10–15% of couples, and male factor accounts for half of the cases. To obtain human male germ cells ‘especially functional spermatids’ is essential for treating male infertility. Currently, much progress has been made on generating male germ cells, including spermatogonia, spermatocytes, and spermatids, from various types of stem cells. These germ cells can also be used in investigation of the pathology of male infertility. In this review, we focused on advances on obtaining male differentiated germ cells from different kinds of stem cells, with an emphasis on the embryonic stem (ES) cells, the induced pluripotent stem (iPS) cells, and spermatogonial stem cells (SSCs). We illustrated the generation of male differentiated germ cells from ES cells, iPS cells and SSCs, and we summarized the phenotype for these stem cells, spermatocytes and spermatids. Moreover, we address the differentiation potentials of ES cells, iPS cells and SSCs. We also highlight the advantages, disadvantages and concerns on derivation of the differentiated male germ cells from several types of stem cells. The ability of generating mature and functional male gametes from stem cells could enable us to understand the precise etiology of male infertility and offer an invaluable source of autologous male gametes for treating male infertility of azoospermia patients.

Colorectal cancer is one of the most common and fatal tumors. However, molecular mechanisms underlying carcinogenesis of colorectal cancer remain largely undefined. Here, we explored the expression and function of Nodal in colon cancer stem cells (CCSCs). Nodal and its receptors were present in numerous human colorectal cancer cell lines. NODAL and ALK-4 were coexpressed in human colon cancerous tissues, and NODAL, CD24, and CD44, markers for CCSCs, were expressed at higher levels in human colon cancerous tissues than adjacent noncancerous colon tissues. Human CCSCs were isolated by magnetic activated cell sorting using anti-CD24 and anti-CD44. Nodal transcript and protein were hardly detectable in CD44- or CD24-negative human colorectal cancer cell lines, whereas Nodal and its receptors were present in CCSCs. Notably, Nodal facilitated spheroid formation of human CCSCs, and phosphorylation of Smad2 and Smad3 was activated by Nodal in cells of spheres derived from human CCSCs. Collectively, these results suggest that Nodal promotes the self-renewal of human CCSCs and mediate carcinogenesis of human colorectal cancer via an autocrine manner through Smad2/3 pathway. This study provides a novel insight into molecular mechanisms controlling fate of human CCSCs and offers new targets for gene therapy of human colorectal cancer.

Spermatogenesis is a special process by which spermatogonial stem cells (SSCs) divide and differentiate to male gametes called mature spermatozoa. SSCs are the unique cells because they are adult stem cells that transmit genetic information to subsequent generations. Accumulating evidence has demonstrated that SSCs can be reprogrammed to acquire pluripotency to become embryonic stem-like cells that differentiate into all cell lineages of the three germ layers, highlighting potential important applications of SSCs for regenerative medicine. Recent studies from peers and us have made great achievements on the characterization, isolation, and culture of mouse and human SSCs, which could lead to better understanding the biology of SSCs and the applications of SSCs in both reproductive and regenerative medicine. In this review, we first compared the cell identity and biochemical phenotypes between mouse SSCs and human SSCs. Notably, the cell types of mouse and human SSCs are distinct, and human SSCs share some but not all phenotypes with mouse SSCs. The approaches for isolating SSCs as well as short- and long-term culture of mouse SSCs and short-period culture of human SSCs were also discussed. We further addressed the new advances on the self-renewal of SSCs with an aim to establish the long-term culture of human SSCs which has not yet been achieved.

This study was designed to explore the regulatory effects of male germ cell secreting factor NODAL on Sertoli cell fate decisions from obstructive azoospermia (OA) and nonobstructive azoospermia (NOA) patients. Human Sertoli cells and male germ cells were isolated using two-step enzymatic digestion and SATPUT from testes of azoospermia patients. Expression of NODAL and its multiple receptors in human Sertoli cells and male germ cells were characterized by reverse transcription-polymerase chain reaction (RT-PCR) and immunochemistry. Human recombinant NODAL and its receptor inhibitor SB431542 were employed to probe their effect on the proliferation of Sertoli cells using the CCK-8 assay. Quantitative PCR and Western blots were utilized to assess the expression of Sertoli cell functional genes and proteins. NODAL was found to be expressed in male germ cells but not in Sertoli cells, whereas its receptors ALK4, ALK7, and ACTR-IIB were detected in Sertoli cells and germ cells, suggesting that NODAL plays a regulatory role in Sertoli cells and germ cells via a paracrine and autocrine pathway, respectively. Human recombinant NODAL could promote the proliferation of human Sertoli cells. The expression of cell cycle regulators, including CYCLIN A, CYCLIN D1 and CYCLIN E, was not remarkably affected by NODAL signaling. NODAL enhanced the expression of essential growth factors, including GDNF, SCF, and BMP4, whereas SB431542 decreased their levels. There was not homogeneity of genes changes by NODAL treatment in Sertoli cells from OA and Sertoli cell-only syndrome (SCO) patients. Collectively, this study demonstrates that NODAL produced by human male germ cells regulates proliferation and numerous gene expression of Sertoli cells.

Background Severe shortage of liver donors and hepatocytes highlights urgent requirement of extra-liver and stem cell source of hepatocytes for treating liver-related diseases. Here we hypothesized that spermatogonial stem cells (SSCs) can directly transdifferentiate to hepatic stem-like cells capable of differentiating into mature hepatocyte-like cells in vitro without an intervening pluripotent state. Results SSCs first changed into hepatic stem-like cells since they resembled hepatic oval cells in morphology and expressed Ck8, Ck18, Ck7, Ck19, OV6, and albumin. Importantly, they co-expressed CK8 and CK19 but not ES cell markers. Hepatic stem-like cells derived from SSCs could differentiate into small hepatocytes based upon their morphological features and expression of numerous hepatic cell markers but lacking of bile epithelial cell hallmarks. Small hepatocytes were further coaxed to differentiate into mature hepatocyte-like cells, as identified by their morphological traits and strong expression of Ck8, Ck18, Cyp7a1, Hnf3b, Alb, Ta t, Ttr, albumin, and CYP1A2 but not Ck7 or CK19. Notably, these differentiated cells acquired functional attributes of hepatocyte-like cells because they secreted albumin, synthesized urea, and uptake and released indocyanine green. Moreover, phosphorylation of ERK1/2 and Smad2/3 rather than Akt was activated in hepatic stem cells and mature hepatocytes. Additionally, cyclin A, cyclin B and cyclin E transcripts and proteins but not cyclin D1 or CDK1 and CDK2 transcripts or proteins were reduced in mature hepatocyte-like cells or hepatic stem-like cells derived from SSCs compared to SSCs. Conclusions SSCs can transdifferentiate to hepatic stem-like cells capable of differentiating into cells with morphological, phenotypic and functional characteristics of mature hepatocytes via the activation of ERK1/2 and Smad2/3 signaling pathways and the inactivation of cyclin A, cyclin B and cyclin E. This study thus provides an invaluable source of mature hepatocytes for treating liver-related diseases and drug toxicity screening and offers novel insights into mechanisms of liver development and cell reprogramming.