Mesenchymal stromal cells (MSCs) are adult multipotent stem cells residing as pericytes in various tissues and organs where they can differentiate into specialized cells to replace dying cells and damaged tissues. These cells are commonly found at injury sites and in tumors that are known to behave like " wounds that do not heal.” In this article, we discuss the mechanisms of MSCs in migrating, homing, and repairing injured tissues. We also review a number of reports showing that tumor microenvironment triggers plasticity mechanisms in MSCs to induce malignant neoplastic tissue formation, maintenance, and chemoresistance, as well as tumor growth. The antitumor properties and therapeutic potential of MSCs are also discussed.

Master developmental pathways, such as Notch, Wnt, and Hedgehog, are signaling systems that control proliferation, cell death, motility, migration, and stemness. These systems are not only commonly activated in many solid tumors, where they drive or contribute to cancer initiation, but also in primary and metastatic tumor development. The reactivation of developmental pathways in cancer stroma favors the development of cancer stem cells and allows their maintenance, indicating these signaling pathways as particularly attractive targets for efficient anticancer therapies, especially in advanced primary tumors and metastatic cancers. Metastasis is the worst feature of cancer development. This feature results from a cascade of events emerging from the hijacking of epithelial-mesenchymal transition, angiogenesis, migration, and invasion by transforming cells and is associated with poor survival, drug resistance, and tumor relapse. In the present review, we summarize and discuss experimental data suggesting pivotal roles for developmental pathways in cancer development and metastasis, considering the therapeutic potential. Emerging targeted antimetastatic therapies based on Notch, Wnt, and Hedgehog pathways are also discussed.

Overall, the antiproliferative and antioxidant activities of some of the extracts lend some support to their use in the traditional medicine of Adamawa Region, Cameroon to treat cancer.

Background Senecio biafrae (Asteraceae) is a medicinal plant widely used by traditional healers in the western region of Cameroon for the treatment of female infertility. This experiment was designed to evaluate the effect of the aqueous extract from leaves and stems of S. biafrae (AESb) on the onset of puberty and some biochemical and physiological parameters of reproduction in immature Wistar female rats. Methods Different doses of AESb were daily and orally administered to immature female rats (13 animals/group) for 30 days. At the end of the treatment period, six animal of each experimental group were sacrificed and their body, ovarian, uterus weight; uterine, ovarian protein or cholesterol level as well as data on puberty onset recorded. The remaining animals of each group were used for the fertility test and some gestational parameters recorded. Results A linear increase in the growth rate of all animals was observed. The body weight gain in animals treated at the dose of 8 mg/kg of AESb significantly increased (p < 0.05) after 25 days of treatment while those receiving the doses of 32 and 64 mg/kg presented a significantly low body weight gain starting from the 19 th day till the end of the treatment period. The ages (days) of animals at vaginal opening (VO) was significantly reduced (p < 0.05) in those treated with the doses of 32 (41.25 ± 0.51) and 64 mg/kg (41.42 ± 0.54) as compared to control animals (43.33 ± 0.73). AESb significantly increased (p < 0.05) the ovarian weight and the number of corpora lutea in animals treated with 8 mg/kg as well as the uterine weight and protein levels irrespective of the dose. No significant effect of the extract on various fertility and gestational parameters was registered. Conclusion The overall results of the present study provide evidence on the puberty onset induction and ovarian folliculogenesis effect of AESb in immature female rat.

The role of mesenchymal stromal cells (MSCs) in the tumor microenvironment is well described. Available data support that MSCs display anticancer activities, and that their reprogramming by cancer cells in the tumor microenvironment induces their switch toward pro-tumorigenic activities. Here we discuss the recent evidence of pro-tumorigenic effects of stromal cells, in particular (i) MSC support to cancer cells through the metabolic reprogramming necessary to maintain their malignant behavior and stemness, and (ii) MSC role in cancer cell immunosenescence and in the establishment and maintenance of immunosuppression in the tumor microenvironment. We also discuss the mechanisms of tumor microenvironment mediated reprogramming of MSCs, including the effects of hypoxia, tumor stiffness, cancer-promoting cells, and tumor extracellular matrix. Finally, we summarize the emerging strategies for reprogramming tumor MSCs to reactivate anticancer functions of these stromal cells.

The tumor microenvironment fuels tumorigenesis and induces the development of resistance to anticancer drugs. A growing number of reports support that the tumor microenvironment mediates these deleterious effects partly by overexpressing insulin-like growth factor 1 (IGF-1). IGF-1 is known for its role to support cancer progression and metastasis through the promotion of neovascularization in transforming tissues, and the promotion of the proliferation, maintenance and migration of malignant cells. Anti-IGF therapies showed potent anticancer effects and the ability to suppress cancer resistance to various chemotherapy drugs in in vivo and in vitro preclinical studies. However, high toxicity and resistance to these agents are increasingly being reported in clinical trials. We review data supporting the notion that tumor microenvironment mediates tumorigenesis partly through IGF-1 signaling pathway. We also discuss the therapeutic potential of IGF-1 receptor targeting, with special emphasis on the ability of IGF-R silencing to overcome chemotherapy drug resistance, as well as the challenges for clinical use of anti-IGF-1R therapies.

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