In this study we used a biocomplex constructed from dental pulp stem/progenitor cells (DPCs) and a collagen sponge scaffold for oro-maxillo-facial (OMF) bone tissue repair in patients requiring extraction of their third molars. The experiments were carried out according to our Internal Ethical Committee Guidelines and written informed consent was obtained from the patients. The patients presented with bilateral bone reabsorption of the alveolar ridge distal to the second molar secondary to impaction of the third molar on the cortical alveolar lamina, producing a defect without walls, of at least 1.5 cm in height. This clinical condition does not permit spontaneous bone repair after extraction of the third molar, and eventually leads to loss also of the adjacent second molar. Maxillary third molars were extracted first for DPC isolation and expansion. The cells were then seeded onto a collagen sponge scaffold and the obtained biocomplex was used to fill in the injury site left by extraction of the mandibular third molars. Three months after autologous DPC grafting, alveolar bone of patients had optimal vertical repair and complete restoration of periodontal tissue back to the second molars, as assessed by clinical probing and X-rays. Histological observations clearly demonstrated the complete regeneration of bone at the injury site. Optimal bone regeneration was evident one year after grafting. This clinical study demonstrates that a DPC/collagen sponge biocomplex can completely restore human mandible bone defects and indicates that this cell population could be used for the repair and/or regeneration of tissues and organs.

Tumors are composed of different types of cancer cells that contribute to tumor heterogeneity. Among these populations of cells, cancer stem cells (CSCs) play an important role in cancer initiation and progression. Like their stem cells counterpart, CSCs are also characterized by self-renewal and the capacity to differentiate. A particular population of CSCs is constituted by mesenchymal stem cells (MSCs) that differentiate into cells of mesodermal characteristics. Several studies have reported the potential pro-or anti-tumorigenic influence of MSCs on tumor initiation and progression. In fact, MSCs are recruited to the site of wound healing to repair damaged tissues, an event that is also associated with tumorigenesis. In other cases, resident or migrating MSCs can favor tumor angiogenesis and increase tumor aggressiveness. This interplay between MSCs and cancer cells is fundamental for cancerogenesis, progression, and metastasis. Therefore, an interesting topic is the relationship between cancer cells, CSCs, and MSCs, since contrasting reports about their respective influences have been reported. In this review, we discuss recent findings related to conflicting results on the influence of normal and CSCs in cancer development. The understanding of the role of MSCs in cancer is also important in cancer management. Stem Cells Translational Medicine 2017;6:2115–2125

Osteosarcoma is the most common primary tumour of bone. Solid tumours are made of heterogeneous cell populations, which display different goals and roles in tumour economy. A rather small cell subset can hold or acquire stem potentials, gaining aggressiveness and increasing expectancy of recurrence. The CD133 antigen is a pentaspan membrane glycoprotein, which has been proposed as a cancer stem cell marker, since it has been previously demonstrated to be capable of identifying a cancer initiating subpopulation in brain, colon, melanoma and other solid tumours. Therefore, our aim was to observe the possible presence of cells expressing the CD133 antigen within solid tumour cell lines of osteosarcoma and, then, understand their biological characteristics and performances. In this study, using SAOS2, MG63 and U2OS, three human sarcoma cell lines isolated from young Caucasian subjects, we were able to identify and characterize, among them, CD133⁺ cells showing the following features: high proliferation rate, cell cycle detection in a G2\M phase, positivity for Ki-67, and expression of ABCG2 transporters. In addition, at the FACS, we were able to observe the CD133⁺ cell fraction showing side population profile and forming sphere-clusters in serum-free medium with a high clonogenic efficiency. Taken together, our findings lead to the thought that we can assume that we have identified, for the first time, CD133⁺ cells within osteosarcoma cell lines, showing many features of cancer stem cells. This can be of rather interest in order to design new therapies against the bone cancer.

Pentose phosphate pathway (PPP) is a major glucose metabolism pathway, which has a fundamental role in cancer growth and metastasis. Even though PPP blockade has been pointed out as a very promising strategy against cancer, effective anti-PPP agents are not still available in the clinical setting. Here we demonstrate that the natural molecule polydatin inhibits glucose-6-phosphate dehydrogenase (G6PD), the key enzyme of PPP. Polydatin blocks G6PD causing accumulation of reactive oxygen species and strong increase of endoplasmic reticulum stress. These effects are followed by cell cycle block in S phase, an about 50% of apoptosis, and 60% inhibition of invasion in vitro. Accordingly, in an orthotopic metastatic model of tongue cancer, 100 mg/kg polydatin induced an about 30% tumor size reduction with an about 80% inhibition of lymph node metastases and 50% reduction of lymph node size (p < 0.005). Polydatin is not toxic in animals up to a dose of 200 mg/kg and a phase II clinical trial shows that it is also well tolerated in humans (40 mg twice a day for 90 days). Thus, polydatin may be used as a reliable tool to limit human cancer growth and metastatic spread.

This study aimed to identify, isolate, and characterize cancer stem cells from human primary sarcomas. We performed cytometric analyses for stemness and differentiation antigens, including CD29, CD34, CD44, CD90, CD117, and CD133, on 21 human primary sarcomas on the day of surgery. From sarcoma biopsies, we obtained 2 chondrosarcoma‐stabilized cell lines and 2 osteosarcoma stabilized cell lines, on which sphere formation, side population profile, stemness gene expression, and in vivo and in vitro assays were performed. All samples expressed the CD133, CD44, and CD29 markers. Therefore, we selected a CD133 ⁺ subpopulation from stabilized cell lines that displayed the capacity to grow as sarcospheres able to initiate and sustain tumor growth in nonobese diabetic/severe combined (NOD/SCID) mice, to express stemness genes, including OCT3/4, Nanog, Sox2, and Nestin, and to differentiate into mesenchymal lineages, such as osteoblasts and adipocytes. Our findings show the existence of cancer stem cells in human primary bone sarcomas and highlight CD133 as a pivotal marker for identification of these cells. This may be of primary importance in the development of new therapeutic strategies and new prognostic procedures against these highly aggressive and metastatic tumors.—Tirino, V., Desiderio, V., Paino, F., De Rosa, A, Papaccio, F., Fazioli, F., Pirozzi, G., Papaccio, G. Human primary bone sarcomas contain CD133 ⁺ cancer stem cells displaying high tumorigenicity in vivo. FASEB J. 25, 2022‐2030 (2011). www.fasebj.org