TRIB2 Stimulates Cancer Stem-Like Properties through Activating the AKT-GSK3β-β-Catenin Signaling Axis

Advances in ovarian tumor stem cells and therapy

Ovarian cancer is considered the most lethal among all gynecological malignancies due to its early metastatic dissemination, extensive spread, and malignant ascites. The current standard of care for advanced ovarian cancer involves a combination of cytoreductive surgery and chemotherapy utilizing platinum-based and taxane-based agents. Although initial treatment yields clinical remission in 70-80% of patients, the majority eventually develop treatment resistance and tumor recurrence. A growing body of evidence indicates the existence of cancer stem cells within diverse solid tumors, including ovarian cancer, which function as a subpopulation to propel tumor growth and disease advancement by means of drug resistance, recurrence, and metastasis. The presence of ovarian cancer stem cells is widely considered to be a significant contributor to the unfavorable clinical outcomes observed in patients with ovarian cancer, as they play a crucial role in mediating chemotherapy resistance, recurrence, and metastasis. Ovarian cancer stem cells possess the capacity to reassemble within the entirety of the tumor following conventional treatment, thereby instigating the recurrence of ovarian cancer and inducing resistance to treatment. Consequently, the creation of therapeutic approaches aimed at eliminating ovarian cancer stem cells holds great potential for the management of ovarian cancer. These cells are regarded as one of the most auspicious targets and mechanisms for the treatment of ovarian cancer. There is a pressing need for a comprehensive comprehension of the fundamental mechanisms of ovarian cancer's recurrence, metastasis, and drug resistance, alongside the development of effective strategies to overcome chemoresistance, metastasis, and recurrence. The implementation of cancer stem cell therapies may potentially augment the tumor cells' sensitivity to existing chemotherapy protocols, thereby mitigating the risks of tumor metastasis and recurrence, and ultimately improving the survival rates of ovarian cancer patients.

The role of tribbles homolog 2 in vascular smooth muscle cell proliferation

Tribbles homolog 2 (TRIB2) functions as an adapter protein that regulates signal transductions involved in a variety of cellular functions, including tumorigenesis. However, the role of TRIB2 in the proliferation of vascular smooth muscle cells (VSMCs) and the underlying expression mechanisms remain unclear. The present study investigated the role of TRIB2 in VSMC proliferation and revealed that TRIB2 expression increases following vascular injury and platelet-derived growth factor (PDGF)-BB-stimulated VSMCs. We found that pretreatment with diphenyleneiodonium (a nicotinamide adenine dinucleotide phosphate oxidase inhibitor), U0126 (an inhibitor of mitogen-activated protein kinase kinase 1 [MEK1]), or siRNA targeting the gene encoding early growth response 1 (EGR-1) significantly inhibits PDGF-BB-induced TRIB2 expression in VSMCs. Furthermore, TRIB2 knockdown significantly inhibits PDGF-BB-induced proliferation of VSMCs but does not affect the phosphorylation of AKT. However, phosphorylation of ERK1 and expression of proliferating cell nuclear antibody are significantly suppressed in VSMCs by PDGF-BB stimulation. Thus, PDGF-BB-induced TRIB2 expression is mediated by ROS/ERK/EGR-1 pathways and plays a critical role in VSMC proliferation via modulation of ERK activity. We propose TRIB2 as a promising therapeutic target for the prevention of neointima formation and vascular disease.

Cancer Stem Cells and Their Vesicles, Together with Other Stem and Non-Stem Cells, Govern Critical Cancer Processes: Perspectives for Medical Development

Stem cells, identified several decades ago, started to attract interest at the end of the nineties when families of mesenchymal stem cells (MSCs), concentrated in the stroma of most organs, were found to participate in the therapy of many diseases. In cancer, however, stem cells of high importance are specific to another family, the cancer stem cells (CSCs). This comprehensive review is focused on the role and the mechanisms of CSCs and of their specific extracellular vesicles (EVs), which are composed of both exosomes and ectosomes. Compared to non-stem (normal) cancer cells, CSCs exist in small populations that are preferentially distributed to the niches, such as minor specific tissue sites corresponding to the stroma of non-cancer tissues. At niches and marginal sites of other cancer masses, the tissue exhibits peculiar properties that are typical of the tumor microenvironment (TME) of cancers. The extracellular matrix (ECM) includes components different from non-cancer tissues. CSCs and their EVs, in addition to effects analogous to those of MSCs/EVs, participate in processes of key importance, specific to cancer: generation of distinct cell subtypes, proliferation, differentiation, progression, formation of metastases, immune and therapy resistance, cancer relapse. Many of these, and other, effects require CSC cooperation with surrounding cells, especially MSCs. Filtered non-cancer cells, especially macrophages and fibroblasts, contribute to collaborative cancer transition/integration processes. Therapy developments are mentioned as ongoing preclinical initiatives. The preliminary state of clinical medicine is presented in terms of both industrial development and future treatments. The latter will be administered to specific patients together with known drugs, with the aim of eradicating their tumor growth and metastases.