Long-term cultures of stem/progenitor cells from lobular and ductal breast carcinomas under non-adherent conditions

Biological characteristics of a sub-population of cancer stem cells from two triple-negative breast tumour cell lines

Triple-negative breast tumours (TNBTs) make up 15-20% of all breast tumours. There is no treatment for them, and the role that cancer stem cells (CSCs) have in carcinogenesis is still unclear, so finding markers and therapeutic targets in CSC exosomes requires these cells to exist as a homogeneous cell population. The objective of this work was to determine differences in ultrastructural morphology, proliferative capacity, and mouse-xenotransplantation characteristics of the MDA-MB-231 and MDA-MB-436 TNBT cell lines with the CD44 high /CD24 low phenotype in order to study their exosomes. The results show that the CD44 high /CD24 low MBA-MB-231 cells had a population doubling time of 41.56 h, compared to 44.79 h in the MDA-MB-436 cell line. After magnetic immunoseparation, 18.75% and 14.56% of the stem cell population of the MDA-MB-231 and MDA-MB-436 cell lines, respectively, were of the CD44 high /CD24 low phenotype, which were expanded to reach purities of 80.4% and 87.6%. The same expanded lineage in both cell lines was shown to possess the pluripotency markers Nanog and Oct4. Under a scanning electron microscope, the CD44 high /CD24 low lineage of the MBA-MD-231 cell line formed groups of more interconnected cells than this lineage of the MBA-MD-436 line. A total of 16% of the mice inoculated with the CD44 high /CD24 low lineage of either cell line presented tumours of the breast, lung, and submandibular ganglia, in whose tissues variable numbers of inoculated cells were found 30 days post-inoculation. By magnetic immunoselection, it was possible to isolate in similar quantities and characterize, expand, and xenotransplant the CD44 high /CD24 low lineage of the MDA-MB-231 and MDA-MB-436 cell lines. The former cell line has greater proliferative capacity, the two lines differ under scanning electron microscopy in how they intercommunicate, and both cell lines induce new tumours in mice and persist at least 30 days post-inoculation in the transplanted animal so their exosomes would also be different.

Dysregulated expression of Dicer in invasive ductal breast carcinoma

Several lines of evidence suggest that the global down-regulation of the microRNAome (miRNAome) involved in pathogenesis of various malignancies. Impaired microRNAs processing pathway is one possible mechanism for global down-regulation of the miRNAome. Dicer is a key enzyme in miRNA processing pathway, and dysregulation of its expression has been suggested as a possible cause of miRNAome alterations observed in various cancers. However, Dicer mRNA expression in invasive ductal breast carcinoma (IDC) has not been investigated in depth. Therefore, this study aimed to evaluate the mRNA expression of Dicer in IDC and also to assess the correlation of its expression with clinicopathological parameters including age, histological grade, tumor size and lymph node metastasis. We investigated the expression of the Dicer in seventy fresh invasive ductal breast carcinomas and matched adjacent non-neoplastic tissue by quantitative real-time PCR using validated reference genes. In addition, the possible impact of clinicopathological characteristics on Dicer expression levels was analyzed. Our results showed that Dicer mRNA expression is down-regulated in slightly more than half (51.43 %) of the tumor specimens when compared to adjacent non-neoplastic tissue. Comparison of the Dicer expression level between tumor and matched adjacent non-neoplastic tissue showed that there is no statistical significant differences between them (P = 0.425). We also found that Dicer mRNA expression in IDC samples was not correlated with clinicopathological features. In conclusion, our findings provide additional evidence to support the hypothesis that Dicer expression down-regulated in breast cancer. This study suggested that the decreased expression of Dicer may be potential underlying mechanism in pathogenesis of IDC.

Inhibition of Hedgehog signalling by NVP-LDE225 (Erismodegib) interferes with growth and invasion of human renal cell carcinoma cells

Background:

Multiple lines of evidence support that the Hedgehog (Hh) signalling has a role in the maintenance and progression of different human cancers. Therefore, inhibition of the Hh pathway represents a valid anticancer therapeutic approach for renal cell carcinoma (RCC) patients. NVP-LDE225 is a Smoothened (Smo) antagonist that induces dose-related inhibition of Hh and Smo-dependent tumour growth.

Methods:

We assayed the effects of NVP-LDE225 alone or in combination with everolimus or sunitinib on the growth and invasion of human RCC models both in vitro and in vivo. To this aim, we used a panel of human RCC models, comprising cells with acquired resistance to sunitinib – a multiple tyrosine kinase inhibitor approved as a first-line treatment for RCC.

Results:

NVP-LDE225 cooperated with either everolimus or sunitinib to inhibit proliferation, migration, and invasion of RCC cells even in sunitinib-resistant (SuR) cells. Some major transducers involved in tumour cell motility, including paxillin, were also efficiently inhibited by the combination therapy, as demonstrated by western blot and confocal microscopy assays. Moreover, these combined treatments inhibited tumour growth and increased animal survival in nude mice xenografted with SuR RCC cells. Finally, lung micrometastasis formation was reduced when mice were treated with NVP-LDE225 plus everolimus or sunitinib, as evidenced by artificial metastatic assays.

Conclusions:

Hedgehog inhibition by NVP-LDE225 plus sunitinib or everolimus bolsters antitumour activity by interfering with tumour growth and metastatic spread, even in SuR cells. Thus, this new evidence puts forward a new promising therapeutic approach for RCC patients.

Cell sorting in cancer research--diminishing degree of cell heterogeneity

Increasing evidence of intratumor heterogeneity and its augmentation due to selective pressure of microenvironment and recent achievements in cancer therapeutics lead to the need to investigate and track the tumor subclonal structure. Cell sorting of heterogeneous subpopulations of tumor and tumor-associated cells has been a long established strategy in cancer research. Advancement in lasers, computer technology and optics has led to a new generation of flow cytometers and cell sorters capable of high-speed processing of single cell suspensions. Over the last several years cell sorting was used in combination with molecular biological methods, imaging and proteomics to characterize primary and metastatic cancer cell populations, minimal residual disease and single tumor cells. It was the principal method for identification and characterization of cancer stem cells. Analysis of single cancer cells may improve early detection of tumors, monitoring of circulating tumor cells, evaluation of intratumor heterogeneity and chemotherapeutic treatments. The aim of this review is to provide an overview of major cell sorting applications and approaches with new prospective developments such as microfluidics and microchip technologies.

MicroRNAs in endometrial cancer

MicroRNAs (miRNAs) are small non-coding ribonucleic acids (RNAs) of approximately 22 bp that induce RNA interference with a complementary messenger RNA (mRNA) and act in silencing of mRNA. miRNAs are strongly associated with cancer development and those involved in carcinogenesis are classified into oncogenic miRNAs and tumor suppressor miRNAs (tumor suppressor miRs). Specific miRNAs are expressed in various tissues and changes in regulation of gene expression are thought to cause carcinogenesis. Thus, tissue-specific miRNAs may be biomarkers for cancer diagnosis and prognosis. Approaches to application of miRNAs as cancer therapy are also ongoing, based on the involvement of miRNAs in carcinogenesis. In endometrial cancer, miRNAs are associated with regulation of gene expression, epigenetic dysfunction and carcinogenesis. Thus, miRNAs are likely to have key roles in diagnosis, prognostic prediction, and therapy in endometrial cancer.

Cytometric and biochemical characterization of human breast cancer cells reveals heterogeneous myoepithelial phenotypes

To determine whether cell cultures maintain the cellular heterogeneity of primary tissues and may therefore be used for in vitro modeling of breast cancer subtypes, we evaluated the expression of a cell surface marker panel in breast cancer cell cultures derived from various subtypes of human breast carcinoma. We used a four-color flow cytometry strategy to immunophenotype seven human breast cancer cell cultures and four reference breast cancer cell lines. We analyzed 28 surface markers selected based on their potential to distinguish epithelial or mesenchymal lineage, to identify stem cell populations, and to mediate cell adhesion and migration. We determined their ability to form mammospheres and analyzed luminal cytokeratins CK18, CK19, and myoepithelial/basal CK5, SMA (alpha-smooth muscle actin), and vimentin expression by western blot. All cell surface markers showed a unimodal profile. Ten/28 markers were homogenously expressed. Four (CD66b, CD66c, CD165, CD324) displayed negative/low expression. Six (CD29, CD55, CD59, CD81, CD151, CD166) displayed homogenous high expression. Eighteen (CD9, CD10, CD24, CD26, CD44, CD47, CD49b, CD49f, CD54, CD61, CD90, CD105, CD133, CD164, CD184, CD200, CD227, CD326) were heterogeneously expressed. Spearman's rank test demonstrated a significant correlation (p< 0.001) between mesenchymal phenotype and breast cancer cell cultures. Breast cancer cell cultures, all CD44+, displayed concomitant high expression of only three antigens (CD10, CD54, CD90), and low expression of CD326; cell cultures formed mammospheres and expressed CK5, SMA and vimentin, and were weakly CK19-positive. We demonstrate that breast cancer cell cultures preserve inter-tumor heterogeneity and express stem/progenitor markers that can be identified, quantified and categorized by flow cytometry. Therefore, cell cultures can be used for in vitro modeling of breast cancer subtypes; immunophenotyping may mirror breast cancer heterogeneity and reveal molecular characteristics of individual tumors useful for testing target therapy.

[Enrichment and function research of large cell lung cancer stem cell-like cells]

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。