Search

The therapy of colorectal cancer (CRC) patients is often unsuccessful because of the presence of cancer stem cells (CSCs) resistant to conventional approaches. Dendritic cells (DC)-based protocols are believed to effectively supplement CRC therapy. Our study was aimed to assess how the number and properties of CSCs isolated from tumor tissue of CRC patients will affect the biological characteristics of in vitro modified DCs. Similar procedures were conducted with the using of CRC HCT116 and HT29 cell lines. We found that the detailed configuration of CSC-like markers significantly influenced the maturation and activation of DCs after stimulation with cancer cells lysates or culture supernatants. This basic stimulatory effect was enhanced by LPS that is normally present in CRC CSCs niche. The increased number of CD29 + and CD44 + CSCs presented the opposite impact on treated DCs as showed by many significant correlations. The CD133 + CSCs seemed to impair the functions of DCs. The more CD133 + CSCs in tumor sample the lower number of activated DCs evidenced after stimulation. Moreover, our results showed superiority of the spherical culture model over the adherent one since spherical HCT116 and HT29 cells presented similar influence on DCs properties as CRC patients cancer cells. We concluded that the DCs features may depend directly on the properties of CSCs affected by progression status of tumor.

There is growing interest in developing drugs that specifically target glioblastoma tumor-initiating cells (TICs). Current cell culture methods, however, cannot cost-effectively produce the large numbers of glioblastoma TICs required for drug discovery and development. In this paper we report a new method that encapsulates patient-derived primary glioblastoma TICs and grows them in 3 dimension thermoreversible hydrogels. Our method allows long-term culture (~50 days, 10 passages tested, accumulative ~>10(10)-fold expansion) with both high growth rate (~20-fold expansion/7 days) and high volumetric yield (~2.0 × 10(7) cells/ml) without the loss of stemness. The scalable method can be used to produce sufficient, affordable glioblastoma TICs for drug discovery.

Tumors evolve from initial tumorigenic events into increasingly aggressive behaviors in a process usually driven by subpopulations of cancer stem cells (CSCs). Mesenchymal stromal/stem cells (MSCs) may act as the cell-of-origin for sarcomas, and CSCs that present MSC features have been identified in sarcomas due to their ability to grow as self-renewed floating spheres (tumorspheres). Accordingly, we previously developed sarcoma models using human MSCs transformed with relevant oncogenic events. To study the evolution/emergence of CSC subpopulations during tumor progression, we compared the tumorigenic properties of bulk adherent cultures and tumorsphere-forming subpopulations both in the sarcoma cell-of-origin models (transformed MSCs) and in their corresponding tumor xenograft-derived cells. Tumor formation assays showed that the tumorsphere cultures from xenograft-derived cells, but not from the cell-of-origin models, were enriched in CSCs, providing evidence of the emergence of bona fide CSCs subpopulations during tumor progression. Relevant CSC-related factors, such as ALDH1 and SOX2, were increasingly upregulated in CSCs during tumor progression, and importantly, the increased levels and activity of ALDH1 in these subpopulations were associated with enhanced tumorigenicity. In addition to being a CSC marker, our findings indicate that ALDH1 could also be useful for tracking the malignant potential of CSC subpopulations during sarcoma evolution.

One of greatest challenges to the successful treatment of cancer is drug resistance. An exciting approach is the eradication of cancer stem cells (CSCs). However, little is known about key signals regulating the formation and expansion of CSCs. Moreover, lack of a reliable predictive preclinical model has been a major obstacle to discover new cancer drugs and predict their clinical activity. Here, in ovarian cancer, a highly chemoresistant tumor that is rapidly fatal, we provide the first evidence demonstrating the causal involvement of mechanical stimulus in the CSC phenotype using a customizable microfluidic platform and three-dimensional spheroids, which most closely mimic tumor behavior. We found that ovarian cancer cells significantly acquired the expression of epithelial-to-mesenchymal transition and CSC markers and a remarkable chemoresistance to clinically relevant doses of frontline chemotherapeutic drugs cisplatin and paclitaxel when grown under fluid shear stress, which corroborates with the physiological attainable levels in the malignant ascites, but not under static condition. Furthermore, we uncovered a new link of microRNA-199a-3p, phosphatidylinositol 3-kinase/Akt, and multidrug transporter activation in shear stress-induced CSC enrichment. Our findings shed new light on the significance of hydrodynamics in cancer progression, emphasizing the need of a flow-informed framework in the development of therapeutics.

The mortality rate of ovarian cancer remains high due to late diagnosis and recurrence. A fundamental step toward improving detection and treatment of this lethal disease is to understand its origin. A growing number of studies have revealed that ovarian cancer can develop from multiple extra-ovarian origins, including fallopian tube, gastrointestinal tract, cervix and endometriosis. However, the mechanism leading to their ovarian localization is not understood. We utilized in vitro, ex vivo, and in vivo models to recapitulate the process of extra-ovarian malignant cells migrating to the ovaries and forming tumors. We provided experimental evidence to support that ovulation, by disrupting the ovarian surface epithelium and releasing chemokines/cytokines, promotes the migration and adhesion of malignant cells to the ovary. We identified the granulosa cell-secreted SDF-1 as a main chemoattractant that recruits malignant cells towards the ovary. Our findings revealed a potential molecular mechanism of how the extra-ovarian cells can be attracted by the ovary, migrate to and form tumors in the ovary. Our data also supports the association between increased ovulation and the risk of ovarian cancer. Understanding this association will lead us to the development of more specific markers for early detection and better prevention strategies.