Treatment of CD33-directed chimeric antigen receptor-modified T cells in one patient with relapsed and refractory acute myeloid leukemia.

We conducted a clinical trial to assess the feasibility and efficacy of CD33-directed chimeric antigen receptor-modified T cells (CART-33) for the treatment of refractory acute myeloid leukemia (AML). A 41-year-old male patient with AML was enrolled and received a total of 1.12 × 10(9) autologous CART-33 cells, of which ~38% were transduced with CAR. The CART-33 infusion alone induced rigorous chills and fevers; drastic fluctuations of his preexisting pancytopenia; elevated serum cytokine levels, including interleukin (IL)-6, IL-8, tumor necrosis factor-α, and interferon-γ; slight transient hyperbilirubinemia within 2 weeks; a subsequent intermittent moderate fever; and reversed fluctuation of the pancytopenia. A marked decrease of blasts in the bone marrow was observed on examination 2 weeks after therapy, and there was a gradual increase until florid disease progression occurred at 9 weeks after the cell infusion. These observations warrant further research on CART-33 treatment in refractory AML and may spur efforts to extend the CART-33-induced tumor burden to the preparation of other intensive strategies, such as hematopoietic stem cell transplantation. This study is registered at www.ClinicalTrials.gov as NCT01864902.

Effective response and delayed toxicities of refractory advanced diffuse large B-cell lymphoma treated by CD20-directed chimeric antigen receptor-modified T cells.

We conducted a trial testing a CD20-specific CAR coupled with CD137 and the CD3ζ moiety in patients with chemotherapy refractory advanced diffuse large B cell lymphomas (DLBCL). Seven patients were enrolled. One of the two patients with no bulky tumor obtained a 14-month durable and ongoing complete remission by cell infusion only, and another attained a 6-month tumor regression. Four of five patients with bulky tumor burden were evaluable for clinical efficacy, three of which attained 3- to 6-month tumor regression. Delayed toxicities related to cell infusion are directly correlated to tumor burden and tumor-harboring sites, and mainly included cytokine release symptoms, tumor lysis symptoms, massive hemorrhage of the alimentary tract and aggressive intrapulmonary inflammation surrounding extranodal lesions. These results show firstly that anti-CD20 CART cells can cause prolonged tumor regression in combination with debulking conditioning regimens for advanced DLBCL. This study is registered at www.clinicaltrials.gov as NCT01735604.

Separation and purification of Escherichia coli-expressed human thymosin-α1 using affinity chromatography and high-performance liquid chromatography.

In this study, a human thymosin-α1 (hTα1) fusion protein was overexpressed in Escherichia coli (E. coli). The hexahistidine-tagged hTα1 fusion protein was obtained in soluble form in cells of the engineered E. coli strain BL21 (DE3)/pET-28a-hTα1 that had been induced with isopropyl -D-1-thiogalactopyranoside (IPTG). The recombinant protein accounted for approximately 50-60% of the total protein. We then developed and validated a separation method for hTα1 from E. coli cells based on thermal denaturation, nickel-resin affinity chromatography and high-performance liquid chromatography. The purification method showed good reproducibility and was easy to operate. Purified recombinant hTα1 of high homogeneity was characterized and found to be of high purity (over 99%), as determined by high-voltage electrophoresis and high-performance liquid chromatography analysis. Isoelectric focusing analysis indicated a pI of approximately 4.0, and full wavelength screening showed an optimal absorbance wavelength at around 214nm.

RNA interference remarkably suppresses bcl-2 gene expression in cancer cells in vitro and in vivo.

Bcl-2 is an anti-apoptotic protein. If the level of Bcl-2 protein can be reduced sufficiently in tumors using RNA interference (RNAi) to target the gene message, the apoptosis of tumor cells may be promoted. In this study, we synthesized 19 nucleotides (nts) small interference RNA (siRNA) constructs suppressing bcl-2 gene expression in human tumor cells (HeLaB2 and BGC-823 cell lines) in vitro. The bcl-2 gene expression levels were significantly reduced when these siRNA were transfected into experimental two tumor cells for 72 hours. The apoptosis process was also examined in the tumor cells. Here we synthesized siRNA from a DNA template under the control of the RNA polymerase III promoter in transfected tumor cells. Using this DNA vector-based approach, we found that the siRNA efficiently and specifically inhibited the synthesis of protein encoded by the bcl-2 gene in HeLaB2 and BGC-823 tumor cells. Tumor growth was inhibited by 66.5% with 2mg/kg pSilencer 3.1H1-bcl-2 in mouse liver tumor-bearing BALB/c mice. This approach may prove to be a valuable clinical technique for the analysis of specific gene functions and gene therapy of malignant tumors that utilize the bcl-2 gene via RNA interference.

The methods for determining the purity and in vitro or in vivo activity of recombinant human endostatin.

In order to establish the methods of high-performance liquid chromatography (HPLC) for determining the purity of recombinant human endostatin (rhEndostatin) and in vitro or in vivo activity of rhEndostatin, two columns were firstly used in HPLC analysis for determining the purity of rhEndostatin, including Waters Symmetry 300C4 (4.6 mm x 250 mm, 5 microm) and the Superdex75 HR 10/30. Cell lines, bovine capillary endothelial cells (BCEs) or human umbilical vein endothelial cells (HUVECs) expression human vascular endothelial growth factor (hVEGF) were used in method MTT or LDH as substrate, respectively. The bioactivity in vivo was assayed by the anti-tumor proliferation rate in H22 liver tumor-bearing mice. The results showed that the retention time of rhEndostatin sample was stable at 19.066 min or 11.506 min in reverse phase HPLC (RP-HPLC) or gel filtering HPLC (GF-HPLC). The stableness, repeat and recovery rates were over 99% in both methods and there was no statistical difference between these two methods (p > 0.05). In nonserum culture medium, rhEndostatin can sensitively and stably inhibit the proliferation of the HUVEC cells that were transfected with plasmid encoding hVEGF. LDH substrate methods is the most sensitive and stable method. The anti-tumor activity in H22 tumor-bearing mice was also highly repeatable and had an inhibition rate over 50% at 20 mg kg(-1) weight. As a conclusion, the RP-HPLC and GF-HPLC set up in this paper are highly repeatable, accurate and sensitive for detecting the purity of rhEndostatin. The bioactivity of rhEndostatin can be measured through detection the proliferation-inhibition on HUVECs transfectants with hVEGF in vitro or on H22 liver tumor in vivo.

Pluripotent reprogramming and lineage reprogramming: promises and challenges in cardiovascular regeneration.

Cardiovascular disease is a leading cause of death in industrialized countries. Scientists are trying to generate cardiomyocytes in vitro and in vivo to repair damaged heart tissue. Pluripotent reprogramming brings an alternative source of embryonic-like stem cells, and the possibility of regenerating mammalian tissues by first reverting somatic cells to induced pluripotent stem cells, followed by redifferentiating these cells into cardiomyocytes. More recently, lineage reprogramming of fibroblasts directly into functional cardiomyocytes has been reported. The procedure does not involve reverting cells back to a pluripotent stage, and, thus, would presumably reduce tumorigenic potential. Interestingly, lineage reprogramming could be used for in situ conversion of cell fate. Moreover, zebrafish-like regenerative mechanism in mammalian heart tissue, which was observed in mice within the first week of postpartum, should be further addressed. Here, we review the landmark progresses of the two major reprogramming strategies, compare their pros and cons in cardiovascular regeneration, and forecast the future directions of cardiac repair.

The four-herb Chinese medicine ANBP enhances wound healing and inhibits scar formation via bidirectional regulation of transformation growth factor pathway.

The four-herb Chinese medicine ANBP is a pulverized mixture of four herbs including Agrimonia Eupatoria (A), Nelumbo Nucifera Gaertn (N), Boswellia Carteri (B) and Pollen Typhae Angustifoliae (P). The combination of the four herbs was first described in Chinese canonical medicine about 2000 years ago for treatment of various trauma disorders, such as hemostasis, antiinflammatory, analgesia, and wound healing, etc. However, the precise mechanisms of ANBP are still unclear. In our study, using rabbit ear hypertrophic scar models of full-thickness skin defect, we showed that local ANBP treatment not only significantly enhanced wound healing by relieving inflammation, increasing formation of granulation tissue and accelerating re-epithelialization, but also reduced scar formation by decreasing collagen production, protuberant height and volume of scars, and increasing collagen maturity. We demonstrated that these effects of ANBP are associated with transforming growth factor (TGF)-ß1-mediated signalling pathways through Smad-dependent pathways. ANBP treatment significantly increased expression of TGF-ß1 and Smad2/3 mRNA at the early stage of wound healing, and led to markedly decrease expression of TGF-ß1 and Smad2/3 compared with the control group after 14 days post-wounding. Taken together, our results defined a bidirectional regulation role of ANBP for TGF-ß1/Smad pathway in promoting wound healing and alleviating scar formation, which may be an effective therapy for human wounds at the earliest stage.

Reprogramming fibroblasts into bipotential hepatic stem cells by defined factors.

Recent studies have demonstrated direct reprogramming of fibroblasts into a range of somatic cell types, but to date stem or progenitor cells have only been reprogrammed for the blood and neuronal lineages. We previously reported generation of induced hepatocyte-like (iHep) cells by transduction of Gata4, Hnf1α, and Foxa3 in p19 Arf null mouse embryonic fibroblasts (MEFs). Here, we show that Hnf1ß and Foxa3, liver organogenesis transcription factors, are sufficient to reprogram MEFs into induced hepatic stem cells (iHepSCs). iHepSCs can be stably expanded in vitro and possess the potential of bidirectional differentiation into both hepatocytic and cholangiocytic lineages. In the injured liver of fumarylacetoacetate hydrolase (Fah)-deficient mice, repopulating iHepSCs become hepatocyte-like cells. They also engraft as cholangiocytes into bile ducts of mice with DDC-induced bile ductular injury. Lineage conversion into bipotential expandable iHepSCs provides a strategy to enable efficient derivation of both hepatocytes and cholangiocytes for use in disease modeling and tissue engineering.

The existence of multipotent stem cells with epithelial-mesenchymal transition features in the human liver bud.

During early stage of embryonic development, the liver bud, arising from the foregut endoderm, is the beginning for the formation of future liver three-dimensional structure. While the gene expression profiles associated with this developmental stage have been well explored, the detailed cellular events are not as clear. Epithelial-mesenchymal transition (EMT) was thought to be essential for cell migration in the early vertebrate embryo but seldom demonstrated in human liver development. In this study, we tried to identify the cell populations with both stem cell and EMT features in the human liver bud. Our in situ studies show that the phenotype of EMT occurs at initiation of human liver development, accompanied by up-regulation of EMT associated genes. A human liver bud derived stem cell line (hLBSC) was established, which expressed not only genes specific to both mesenchymal cells and hepatic cells, but also octamer-binding protein 4 (OCT4) and nanog. Placed in appropriate media, hLBSC differentiated into hepatocytes, adipocytes, osteoblast-like cells and neuron-like cells in vitro. When transplanted into severe combined immunodeficiency mice pre-treated by carbon tetrachloride, hLBSC engrafted into the liver parenchyma and proliferated. These data suggests that there are cell populations with stem cell and EMT-like properties in the human liver bud, which may play an important role in the beginning of the spatial structure construction of the liver.