干细胞样CD8+ T细胞：肿瘤免疫疗法的新生力量

CD8+ T 细胞是抗肿瘤免疫应答的主要执行者。通过重塑CD8+ T 细胞杀伤肿瘤细胞的能力,免疫疗法已在抗肿瘤领域取得重大突破,但临床获益仅局限于部分患者和癌症类型。如何克服CD8+ T细胞功能障碍是肿瘤免疫疗法亟待解决的关键问题。近年来,多项研究揭示了CD8+ T细胞的干性调控机制,发现了干细胞样CD8+ T细胞具有自我更新和增殖能力,阐明了该细胞亚群在维持持续性肿瘤免疫治疗应答中的重要性。本文论述了干细胞样CD8+ T 细胞的分子与功能特征、CD8+ T 细胞干性的细胞内外影响因素,归纳总结了目前靶向CD8+ T细胞的干性重编程策略,进一步展望了靶向CD8+ T细胞干性程序来提高肿瘤免疫疗法疗效的思路和方法。     

人大细胞肺癌干细胞样细胞的富集及其功能研究

背景与目的目前国内外还没有确切的、得到公认的肺癌干细胞的筛选标记分子、指标和方法,常用方法为通过流式细胞技术,借鉴其他肿瘤干细胞分选标记来分选肺癌干细胞,但其筛选特异性低、工作量巨大。本研究采用无血清悬浮培养法富集肺癌干细胞,对肺癌干细胞的筛选方法进行探索。方法采用添加生长因子的无血清培养基对人大细胞肺癌细胞株L9981进行悬浮培养,获得肺癌细胞球体。对含血清培养贴壁L9981细胞和无血清培养成球后的L9981细胞,通过显微镜下观察比较二者的生物学形态,应用Vi-cell细胞活力分析仪计数细胞并绘制生长曲线比较二者的增殖能力,通过Transwell实验研究它们的侵袭能力差异,并通过接种裸鼠观察二者在体内的成瘤性来研究肺癌细胞球体的生物学功能。结果与血清贴壁培养L9981细胞相比,无血清培养L9981细胞成球形生长,贴壁L9981和L9981球体细胞的倍增时间分别为(56.05±1.95)h和(33.00±1.44)h,球体细胞的侵袭和成瘤能力分别为贴壁L9981细胞的5倍和20倍。结论通过无血清悬浮培养的L9981细胞可以形成肺癌球体细胞群,L9981球体细胞的侵袭和成瘤能力均明显高于贴壁L9981细胞,显示L9981球体细胞中富集了肺癌干细胞样的细胞。无血清悬浮培养肺癌球体细胞可作为富集肺癌干细胞样细胞的一种候选方法。     

Identification of cancer stem cell-like side population cells in human nasopharyngeal carcinoma cell line

Side population (SP) cells have been isolated from several solid tumors. They lack distinct molecular markers for cancer stem cells (CSC) and increasing evidence suggests that they may play an important role in tumorigenesis and cancer therapy. However, there are no reports about the existence and function of SP cells in nasopharyngeal carcinoma (NPC) cells thus far. In this study, we scanned SP cells from five NPC cell lines and investigated stem cell characteristics, such as proliferation, self-renewal, and differentiation, using SP cells from the widely-used CNE-2 NPC cell line. We observed a strong tumorigenesis ability of SP cells following in vivo transplantation into nonobese diabetic/severe combined immunodeficient mice. Immunofluorescence revealed that cytokine 19 was highly expressed on SP cells. SP cells were found to be more resistant to chemotherapy and radiotherapy and this was related to the ATP-binding cassette half transporter member 2 of G family protein and Smoothened protein expression, respectively. Our results not only showed that SP cells in human NPC cell line CNE-2 had stem cell characteristics in vitro but also showed that they had a strong ability to form tumors in vivo. Importantly, we found the cell marker, cytokine 19, may serve as a potential molecular marker for further characterization of CSC. Taken together, our data shed light on tumorigenesis and therapeutic-resistant mechanisms, which are helpful for developing novel targets for effective clinical treatment of NPC.     

小鼠乳腺癌4T1细胞中肿瘤干细胞样细胞的富集和鉴定

目的：无血清培养基(serum-free medium, SFM)悬浮培养小鼠乳腺癌细胞株4T1,富集并鉴定4T1细胞株中肿瘤干细胞样细胞。方法：通过含EGF、bFGF和B27等细胞因子的SFM培养富集4T1细胞中肿瘤干细胞样细胞,将其接种于含血清培养基（serum-supplemented medium, SSM),观察4T1肿瘤干细胞样细胞分化情况。应用细胞表面标志CD44+CD24-/low和Hoechst 33342染色法检测4T1细胞中肿瘤干细胞样细胞的比例,小鼠致瘤实验验证不同培养条件下4T1肿瘤干细胞样细胞的致瘤能力。结果：4T1细胞在SFM中能够存活、增殖,并形成细胞球,细胞球可连续传代,若重新接种于SSM中可贴壁分化。4T1细胞球中CD44+CD24-/low细胞比例为6.4%~68.9%,侧群 (side population,SP) 细胞比例为7.3%~61.2%,均显著高于SSM中培养的4T1细胞（P<0.05）;随着SFM中细胞球传代次数增加,CD44+CD24-/low细胞和SP细胞的比例逐渐升高。小鼠致瘤实验结果显示,富集了肿瘤干细胞的细胞球比常规培养4T1细胞的致瘤性更强。结论：乳腺癌4T1细胞可在含多种生长因子的SFM中悬浮生长并形成细胞球,4T1细胞中含有的乳腺癌干细胞样细胞可通过SFM培养法富集。     

人结肠癌细胞系肿瘤干细胞特性的初步研究

目的:本研究对8种人结肠癌细胞系的干细胞特性进行初步检测,以寻找适合分选结肠癌干细胞的细胞系.方法:利用流式细胞术,RT-PCR检测8种结肠癌细胞中CD133的表达情况;利用条件培养观察8种细胞系的肿瘤细胞在无血清培养基中的生物学特性;利用裸鼠成瘤模型检测成瘤能力和转移能力.结果:CD133在8种细胞系中的表达有显著差异,最高的HCT116细胞系中CD133+细胞含量为(91.4±5.0)%;各种细胞系细胞均能在无血清培养基中增殖,但只有HCT116细胞能形成典型的"神经球样结构"且具有较高的成瘤能力和转移能力.同等细胞浓度下移植瘤体积HCT116(1.06±0.13) cm3, LOVO(0.22±0.09) cm3, P=0.01, 差异具有统计学意义.结论:相对于其他7种细胞系,HCT116细胞具有多种肿瘤干细胞的生物学特性,更适合于结肠癌干细胞的研究.     

Stem cell-like glioma cells promote tumor angiogenesis through vascular endothelial growth factor

Malignant gliomas are highly lethal cancers dependent on angiogenesis. Critical tumor subpopulations within gliomas share characteristics with neural stem cells. We examined the potential of stem cell-like glioma cells (SCLGC) to support tumor angiogenesis. SCLGC isolated from human glioblastoma biopsy specimens and xenografts potently generated tumors when implanted into the brains of immunocompromised mice, whereas non-SCLGC tumor cells isolated from only a few tumors formed secondary tumors when xenotransplanted. Tumors derived from SCLGC were morphologically distinguishable from non-SCLGC tumor populations by widespread tumor angiogenesis, necrosis, and hemorrhage. To determine a potential molecular mechanism for SCLGC in angiogenesis, we measured the expression of a panel of angiogenic factors secreted by SCLGC. In comparison with matched non-SCLGC populations, SCLGC consistently secreted markedly elevated levels of vascular endothelial growth factor (VEGF), which were further induced by hypoxia. In an in vitro model of angiogenesis, SCLGC-conditioned medium significantly increased endothelial cell migration and tube formation compared with non-SCLGC tumor cell-conditioned medium. The proangiogenic effects of glioma SCLGC on endothelial cells were specifically abolished by the anti-VEGF neutralizing antibody bevacizumab, which is in clinical use for cancer therapy. Furthermore, bevacizumab displayed potent antiangiogenic efficacy in vivo and suppressed growth of xenografts derived from SCLGC but limited efficacy against xenografts derived from a matched non-SCLGC population. Together these data indicate that stem cell-like tumor cells can be a crucial source of key angiogenic factors in cancers and that targeting proangiogenic factors from stem cell-like tumor populations may be critical for patient therapy.     

Stem cells in colon cancer

The concept that cancer might arise from a rare population of cells with stem cell-like properties was proposed 150 years ago. Increasing evidence during the past 2 decades suggests the existence of a small subgroup of cells in cancer that are responsible for tumor growth and proliferation. Stem cells have self-renewing properties; thus, they are appealing candidates for generating the malignant phenotype. Although the concept of stem cells in leukemia has received significant attention for more than the past decade, over the past several years, expression of several surface markers on cancer cells has led to identification of tumor-initiating cells in several solid tumors, including melanoma, brain, breast, prostate, liver, pancreatic, ovarian, and recently, colon cancer. This review will provide an update of the biologic basis of the stem cell model and possible targets for the treatment of colon cancer.     

Clinical implications of cancer stem cell-like side population cells in human laryngeal cancer

In this study, we try to detect and isolate the cancer stem cell-like side population cells (SP) from the laryngeal carcinoma cell line and primary laryngeal carcinoma and explore the clinical implications of SP cells in laryngeal carcinoma. The SP cells and non-side population cells (NSP) cells were sorted by Hoechst 33342 through FACS. The proliferation capacity, invasion ability, migration ability, and tumorigenic activity of the SP cells were evaluated. In addition, the association between the SP cells ratio and the prognostic factors of laryngeal cancer was analyzed. As a result, the percentage of the SP cells in Hep-2 cells was 5.1 %. The SP cells depicted float colonies, but the NSP cells failed to generate the typical cell spheres. The clone formation ratios were 47.47?±?10.20 % vs. 4.98?±?1.41 % in the flat plates and 46.82?±?5.67 % vs. 12.53?±?3.51 % in the soft agar for SP and NSP cells (P?=?0.01 and 0.01). The SP cells depicted a higher migrating potency than the NSP cells in both the transwell assay and scarification test (all P?<?0.05). The matrigel invasion assay showed that the artificial basement membrane penetration rate of SP cells was 39.04?±?4.78 %, which was higher than 25.16?±?4.63 % of the NSP cells (P?<?0.05). Only 10³ SP cells were able to form tumors in mice, whereas 10⁴ NSP cells failed to form tumors. The SP cells were correlated with the differentiation, lymph node metastasis, and clinical stage of the laryngeal cancers. In conclusion, SP cells may be a potential prognostic factor of laryngeal cancer.     

Two cell lines with epithelial cell-like characteristics established from malignant fibrous histiocytomas.

Two malignant fibrous histiocytoma (MFH) cell lines were established: one from a storiform-pleomorph subtype and the other from a myxoid one (codes, MFH-3 and MFH-4). Light microscopic examination revealed large rounded cells, growing mostly separately, in both cell lines. Their ultrastructure was different in various aspects. The MFH-3 cells showed abundant lysosomal activity, a well-developed Golgi apparatus, and a few desmosome-like cell contacts. The MFH-4 cells had a well-developed rough endoplasmic reticulum, delicate bundles of tonofilaments, the formation of pseudoacini, and the presence of small completely developed desmosomes. Based on immunostaining and immunoblotting assays of cultured cells, both cell lines expressed immunoreactivity for vimentin; cytokeratins 7, 8, and 18; desmin; and laminin, but they lacked reactivity for cytokeratins 10 and 19, neurofilament, alpha-smooth muscle actin, S-100 protein, collagen type IV, carcinoembryonic antigen, and antigens specific for macrophages. Fibronectin and, to a variable extent, glial fibrillary acid protein and epithelial membrane antigen (EMA) were detectable in MFH-3 cells only. Furthermore, a 60-kilodalton band was present in both cell lines which was reactive for cytokeratins 8 and 18. The MFH-3 cells had the capacity to grow as xenografts with a carcinoma-like pattern. The cells retained their immunoreactivity for vimentin and cytokeratin 8 and showed the presence of desmosomes. Several of these immunophenotypic features also were noticed in established sarcoma cell lines and in short-term cultures of fibroblasts, smooth muscle cells, and endothelial cells. However, experimental data on the two MFH cell lines show that the MFH cell line may express some immunophenotypic and ultrastructural features considered to be specific for epithelial cells. The MFH cells may originate from multipotential mesenchymal cells with a capacity to differentiate to fibroblast-like cells, and less frequently, to epithelial cells, smooth muscle cells, and Schwannian cells. Such a differentiation became evident when these cells were adapted to culture conditions or grew in nude mice.     

Stem cells and cancer

The cell of origin of cancer has been a strongly debated topic through out the history of cancer research. This review provides a historic framework and a synopsis of how the theories of cancer initiation and progression evolved from early times to the present day. We present the concept of a cancer stem cell, and review for you the literature supporting the existence of cancer stem cells in addition to a brief discussion on our own work supporting a bone marrow-derived source for the cancer stem cell, as well as cells of the cancer stroma.     

干细胞、肿瘤干细胞与肿瘤的关系

干细胞理论认为肿瘤是一种干细胞疾病，该理论为肿瘤的研究及治疗提供了新的方向和靶点。干细胞(stem cell)是一类具有自我更新和增殖分化能力的细胞，肿瘤细胞是一类具有无限增殖和失去分化为成熟细胞能力的细胞，肿瘤干细胞(cancer stem cell)是存在于肿瘤组织中的一小部分具有干细胞性质的细胞群体，能够驱使肿瘤的形成。本文拟综述干细胞、肿瘤干细胞与肿瘤发生发展之间的关系，为肿瘤的研究及临床治疗提供参考。     

乳腺癌细胞系中肿瘤干细胞相关亚群的初步研究

目的 通过乳腺癌细胞系及其干细胞的培养,化疗药干预和流式细胞仪筛选鉴定,探讨不同乳腺癌细胞系中CD44⁺CD24^-/low细胞比例,及富集乳腺癌干细胞相关亚群的方法。方法 通过细胞培养乳腺癌细胞系MCF-7、MDA-MB-231,观察生长曲线,比较化疗药物干预下生长情况;利用流式细胞仪检测两种乳腺癌细胞系中CD44⁺CD24^-/low细胞比例;无血清悬浮培养,化疗药(多西紫杉醇、表阿霉素)干预这两种乳腺癌细胞系,观察其是否形成细胞球。结果 (1)MDA-MB-231细胞系倍增时间短,生长速率高于MCF-7细胞系;(2)MCF-7细胞系中可能存在较大比例肿瘤干细胞,其对化疗抵制,能自我更新;(3)化疗敏感性用两独立样本t检验,MCF-7细胞,差异没有统计学意义;MDA-MB-231细胞,差异有统计学意义,提示MDA-MB-231细胞系对该方案化疗较敏感;(4)无血清悬浮培养,MDA-MB-231细胞系未发现明显细胞球;MCF-7细胞系初次无血清培养约6天出现细胞球。加入化疗药筛选后两种细胞,见大部分肿瘤细胞逐渐死亡,未发现明显细胞球;(5)流式细胞仪检测,MCF-7、MDA-MB-231两种细胞系中主要是CD44⁺CD24⁺亚群和CD44^-CD24⁺亚群,CD44⁺CD24^-/low细胞比例分别2.07%和0.20%。结论 (1)MDA-MB-231细胞系增值较快,恶性度相对较高,其对TA联合化疗药物较敏感;MCF-7细胞系中可能存在少量肿瘤干细胞,对化疗抵制,能自我更新;(2)无血清培养液培养MCF-7细胞系能形成悬浮细胞球;流式细胞仪检测两种细胞系中CD44⁺CD24^-/low细胞比例小;(3)CD44⁺CD24^-/low表型可能不是乳腺癌干细胞唯一特异性的表面标志。     

CD30 induces Reed-Sternberg cell-like morphology and chromosomal instability in classic Hodgkin lymphoma cell lines

Classic Hodgkin lymphoma (cHL) is characterized by multinucleated cells called Reed-Sternberg (RS) cells and genetic complexity. Although CD30 also characterizes cHL cells, its biological roles are not fully understood. In this report, we examined the link between CD30 and these characteristics of cHL cells. CD30 stimulation increased multinucleated cells resembling RS cells. We found chromatin bridges, a cause of mitotic errors, among the nuclei of multinucleated cells. CD30 stimulation induced DNA double-strand breaks (DSBs) and chromosomal imbalances. RNA sequencing showed significant changes in the gene expression by CD30 stimulation. We found that CD30 stimulation increased intracellular reactive oxygen species (ROS), which induced DSBs and multinucleated cells with chromatin bridges. The PI3K pathway was responsible for CD30-mediated generation of multinucleated cells by ROS. These results suggest that CD30 involves generation of RS cell-like multinucleated cells and chromosomal instability through induction of DSBs by ROS, which subsequently induces chromatin bridges and mitotic error. The results link CD30 not only to the morphological features of cHL cells, but also to the genetic complexity, both of which are characteristic of cHL cells.     

5-FU对小鼠乳腺癌4T1细胞株中肿瘤干细胞样细胞的富集作用

目的:探讨以氟尿嘧啶(5-fluorouracil,5-FU)处理并通过荷瘤小鼠模型体内传代的方法富集乳腺癌干细胞样细胞的可行性,为靶向肿瘤干细胞治疗奠定基础.方法:以乳腺癌细胞株4T1皮下接种小鼠制备荷瘤模型,以一定剂量5-FU腹腔注射4周;处死小鼠后取肿瘤组织制成细胞悬液,并接种小鼠制备下一代小鼠荷瘤模型,5-FU处理及再次传代方法同上,共传4代.对照组小鼠给予生理盐水注射,其余处理同模型组.流式细胞术检测各代肿瘤组织中CD44+ CD24-/low细胞比例,Hoechast 33342染色法检测侧群(side population,SP)细胞的比例,免疫组化法检测CD55和ALDH1蛋白的表达,倒置显微镜观察乳腺癌细胞微球体的形成,小鼠致瘤实验检测不同肿瘤细胞的致瘤能力.结果:各代对照组小鼠模型肿瘤组织中CD44+CD24-/low细胞比例为(11.5±0.9)％,SP细胞比例为(9.7±1.3)％,ALDH1表达阴性,CD55强阳性表达细胞数为(0.6±0.3)％,乳腺癌细胞微球体比例为(0.5±0.2)％;5-FU处理组4代小鼠模型肿瘤组织中CD44+ CD24-/low细胞比例分别为(49.8±1.2)％、(56.8％±1.7)％、(66.4±1.5)％、(69.0±1.6)％,SP细胞比例分别为(25.0±1.2)％、(42.6±2.8)％、(58.4±2.1)％、(61.3±2.6)％,ALDH1阳性表达细胞比例为(3.8±0.7)％、(14.1±2.4)％、(25.2±3.1)％、(27.5±2.7)％,CD55强阳性细胞比例为(7.8±1.6)％、(10.1±2.0)％、(15.6±1.4)％、(17.3±1.9)％,乳腺癌细胞微球体形成比例为(5.9±0.4)％;两组各相应指标之间差异均具有统计学意义(P＜0.05或P＜0.01).5-FU作用后富集了肿瘤干细胞的第3代肿瘤细胞的致瘤作用显著强于对照组细胞(P＜0.05).结论:5-FU作用并通过荷瘤小鼠体内传代能够富集小鼠乳腺癌4T1细胞株中的肿瘤干细胞样细胞.     

Mesenchymal stem cell-like cells derived from human gastric cancer tissues

Mesenchymal stem cells (MSCs) have been identified in and isolated from numerous human tissues. The characteristics of mesenchymal stem cells, including their plasticity, the secretion of cytokines, and their low immunogenicity, contribute to their therapeutic potential. It has recently been reported that MSCs are also involved in tumorigenesis and its prognosis. Here, we present the first report of MSC-like cells isolated from human gastric cancer tissues. In our study, gastric cancer-derived MSC-like cells (hGC-MSCs) were isolated from 13 out of 20 cancer tissue samples. Their characteristics, including their morphology, surface antigens, specific gene expression, and differentiation potential, were similar to those of MSCs derived from human bone marrow (hBM-MSCs) but different from gastric cancer cells. The existence of MSC-like cells in gastric cancer tissues suggests that they may be potential targets for cancer therapy and provides an experimental foundation for investigating their role in the initiation and progression of gastric cancers.     

HepG2 cells acquire stem cell-like characteristics after immune cell stimulation

Background

The presence of cancer stem cells (CSCs) is currently regarded as one of the main culprits of tumor formation and therapy failure. It is known that chronic inflammation is associated with CSCs, but it is not clear yet how inflammation affects the development of CSCs. In the present study we aimed to examine the relationship between cancer cell stimulation mediated by immune cells and the acquisition of a CSC-like phenotype.

Methods

Cancer cells derived from single hepatocarcinoma HepG2 cells were treated with mouse splenic B cells (MSBCs) and mouse peritoneal macrophage cells (MPMCs), respectively. The stem cell-like characteristics of the resulting HepG2 cells (MSBC-HepG2 and MPMC-HepG2) were evaluated using different assays, including biomarker assays, in vitro tumoroid and colony forming assays, in vivo tumor forming assays and signal transduction pathway activation assays.

Results

Various stemness characteristics of HepG2 cells, including self-renewal, proliferation, chemoresistance and tumorigenicity were evaluated. The expression levels of stemness-related genes and its encoded proteins in the MSBC-HepG2 and MPMC-HepG2 cells were assessed using RT-PCR and FACS analyses. We found that MSBC-HepG2 and MPMC-HepG2 cells possess hepatic CSC properties, including persistent self-renewal, extensive proliferation, drug resistance, high tumorigenic capacity and over-expression of CSC-related genes and proteins (i.e., EpCAM, ALDH, CD133 and CD44), compared to the parental cells. We also found that 1x10³ MSBC-HepG2 and MPMC-HepG2 cells were able to form tumors in NOD/SCID mice and that the Notch and SHH signaling pathways were highly activated in MSBC-HepG2 cells.

Conclusions

We conclude that the immune system may have a double-edge effect on cancer development. On one hand, immune cells such as B lymphocytes and macrophages may recognize, attack and eliminate cancer cells, whereas on the other hand, they may promote a subset of cancer cells to acquire stem cell-like characteristics.

     

Co-ordination of cell cycle,migration and stem cell-like activity in breast cancer

Migration, proliferation and stem cell-like activity are all key cellular characteristics which aid the formation and progression of breast cancer, in addition to involvement in treatment resistance. Many current therapies aim to target tumour proliferation, and although successful, mortality rates in breast cancer remain significant. Our main objectives were to investigate the relationship between proliferation, migration and stem cell-like activity in breast cancer.We used a panel of cell lines and primary human breast cancer samples to assess the relationship between migration, proliferation and stem cells. We performed live cell sorting according to cell cycle (Hoechst-33324) and in combination with stem-cell markers (CD44/CD24/ESA) followed by assessment of migration and stem cell activity (mammosphere formation).We identified an inverse relationship between proliferation and migration/stem cell-like activity. G0/1 cells showed increased migration and mammosphere formation. Furthermore we identified a subpopulation of low proliferative stem-like cells (CD44+/24lo/ESA+) with increased migration and mammosphere formation that are specifically inhibited by Dickkopf 1 (DKK1) and Dibenzazepine (DBZ) known stem-cell inhibitors.These data show the co-ordination of migration, proliferation and stem cell activity in breast cancer, and has identified a sub-population of stem-like cells, greatly adding to our understanding of the complex nature of stem cell biology.