The recently emerged concept of cancer stem cell (CSC) has led to a new hypothesis on the basis for tumor progression. Basically, the CSC theory hypothesizes the presence of a hierarchically organized and relatively rare cell population, which is responsible for tumor initiation, self-renewal, and maintenance, in addition to accumulation of mutation and resistance to chemotherapy. CSCs have recently been described in breast cancer. Different genetic markers have been used to isolate breast CSCs, none of which have been correlated with the tumorigenicity or metastatic potential of the cells, limiting their precise characterization and clinical application in the development of therapeutic protocols. Here, we sought for subpopulations of CSCs by analyzing 10 judiciously chosen stem cell markers in a normal breast cell line (MCF10-A) and in four human breast cancer cell lines (MCF-7, MDA-MB-231, MDA-MB-435, and Hs578-T) displaying different degrees of metastatic and invasiveness potential. We were able to identify two markers, which are differentially expressed in nontumorigenic versus tumor cells. The CD90 marker was highly expressed in the malignant cell lines. Interestingly, the CD14 molecule displayed higher expression levels in the nontumorigenic cell line. Therefore, we demonstrated that these two markers, which are more commonly used to isolate and characterize stem cells, are differentially expressed in breast tumor cells, when compared with nontumorigenic breast cells. ' 2012 International Society for Advancement of Cytometry Key terms CD90; Thy-1; breast cancer; cancer stem cell; CD14; breast cancer stem cell

We have investigated Amblyomin-X-treated horse melanomas to better understand its mode of action through transcriptome analysis and the in vivo model. Amblyomin-X is a Kunitz-type homologous protein that selectively leads to the death of tumor cells via ER stress and apoptosis, currently under investigation as a new drug candidate for cancer treatment. Melanomas are immunogenic tumors, and a better understanding of the immune responses is warranted. Equine melanomas are spontaneous and not so aggressive as human melanomas are, as this study shows that the in vivo treatment of encapsulated horse melanoma tumors led to a significant reduction in the tumor size or even the complete disappearance of the tumor mass through intratumoral injections of Amblyomin-X. Transcriptome analysis identified ER-and mitochondria-stress, modulation of the innate immune system, apoptosis, and possibly immunogenic cell death activation. Interactome analysis showed that Amblyomin-X potentially interacts with key elements found in transcriptomics. Taken together, Amblyomin-X modulated the tumor immune microenvironment in different ways, at least contributing to induce tumor cell death. Melanoma is a type of cancer arising from the malignant transformation of melanocytes, pigment producing-cells found predominantly in the basal layer of the epidermis and eyes. Cutaneous melanoma is the most aggressive and treatment-resistant form of skin cancer responsible for the vast majority of skin cancer-related deaths in the Caucasian population 1. The global incidence of melanoma continues to increase at an alarming rate, despite decades of public prevention programs in many countries. Around 232,000 new cases of skin cancer were recorded worldwide in 2012, accounting for 1.6% of all new cases of cancer back then, while over 300,000 new cases of melanoma were diagnosed worldwide in 2018, according to the World Cancer Research Foundation 2,3. In Brazil, 1,547 deaths were recorded in 2013 due to melanoma, with around 5,690 new cases reported back then, while around 6,260 new cases were expected due in 2018, according to the National Cancer Institute (INCA) 4. Cutaneous melanoma usually affects a higher proportion of patients, in the age range 40-60 years. They can be treated by surgical excision when detected in the early stage (0, I, II and resectable III), however, in the later stages (unresectable III, IV and recurrent melanoma) the treatment options are chemotherapy, target therapy (BRAF/ MEK pathway inhibitors), immunotherapy (checkpoint blockade CTLA-4 receptor inhibition, PD-1 ↔ PD-L1 axis inhibition, and interferon-gamma immunotherapy), or a combination of them. Death in most patients is caused by metastatic disease which may have evolved from the primary tumor. Therefore, there is a need for new

Specific reports have linked GPC3 with cancer. Its usefulness as a marker has been proved for hepatocarcinoma, melanoma and ovary carcinoma. However, there are no studies analyzing GPC3 usefulness as a biomarker in mammary tumors. The aim of this work was to analyze GPC3 expression in breast tissues and to determine whether it might be useful as a biomarker in breast cancer patients. Expression level of GPC3 mRNA in Brazilian and Argentine human breast tumor (n=121) and peritumoral "normal" tissue (n=77) samples was analyzed using qRT-PCR. GPC3 protein expression was analyzed from 69 breast cancer and 10 peritumoral samples using IHC. Statistical analyses were done to evaluate the clinical-pathological significance of GPC3 expression. We found that Brazilian and Argentine populations are statistically different regarding GPC3 mRNA expression. In Argentine patients a lower GPC3 mRNA expression was found in tumors as compared to peritumoral tissues. No association was found between GPC3 mRNA and protein expression and the clinical-pathological parameters. The Kaplan-Meier curves suggested that elevated levels of GPC3 mRNA are associated with relapse. Our results indicate differential expression of GPC3 in mammary tumors in comparasion to normal breast tissues. They also suggest the potential role of GPC3 as a biomarker and the importance of deepening the study.

Breast cancer is the most prevalent cancer among women, with the basal-like triple negative (TNBC) being the most agressive one, displaying the poorest prognosis within the ductal carcinoma subtype. Due to the lack of adequate molecular targets, the diagnosis and treatment of patients with the TNBC phenotype has been a great challenge. In a previous work, we identified CD90/Thy-1 as being highly expressed in the aggressive high malignancy grade Hs578T basal-like breast tumor cell line, pointing to this molecule as a promising breast tumor marker, which should be further investigated. Here, CD90 expression was analyzed in human breast cancer samples and its functional role was investigated to better assess the oncogenic nature of CD90 in mammary cells. Quantification of CD90 expression in human breast cancer samples, by tissue microarray, showed that high CD90 positivity correlates with metastasis and poor patient survival in the basal-like subtype. The functional genetic approach, by overexpression in the CD90 cDNA in a basal-like normal mammary cell line (MCF10A) and knockdown in a highly malignant cell line (Hs578T), allowed us to demonstrate that CD90 is involved with several cellular processes that lead to malignant transformation, such as: morphological change, increased cell proliferation, invasiveness, metastasis and activation of the EGFR pathway. Therefore, our results reveal that CD90 is involved with malignant transformation in breast cancer cell lines and is correlated with metastasis and poor patient survival in the basal-like subtype, being considered as a promising new breast cancer target.

Mesenchymal stem cells (MSCs) are multipotent cells found in both fetal and adult tissues. MSCs show promise for cellular therapy for several disorders such as those associated with inflammation. In adults, MSCs primarily reside in the bone marrow (BM) and adipose tissues. In BM, MSCs are found at low frequency around blood vessels and trabecula. MSCs are attractive candidates for regenerative medicine given their ease in harvesting and expansion and their unique ability to bypass the immune system in an allogeneic host. Additionally, MSCs exert pathotropism by their ability to migrate to diseased regions. Despite the “attractive” properties of MSCs, their translation to patients requires indepth research. “Off-the-shelf” MSCs are proposed for use in an allogeneic host. Thus, the transplanted MSCs, when placed in a foreign host, could receive cue from the microenvironment for cellular transformation. An important problem with the use of MSCs involves their ability to facilitate the support of breast and other cancers as carcinoma-associated fibroblasts. MSCs could show distinct effect on each subset of cancer cells. This could lead to untoward effect during MSC therapy since the MSCs would be able to interact with undiagnosed cancer cells, which might be in a dormant state. Based on these arguments, further preclinical research is needed to ensure patient safety with MSC therapy. Here, we discuss the basic biology of MSCs, discuss current applications, and provide evidence why it is important to understand MSC biology in the context of diseased microenvironment for safe application.

The skin is a rich source of readily accessible stem cells. The level of plasticity afforded by these cells is becoming increasingly important as the potential of stem cells in Cell Therapy and Regenerative Medicine continues to be explored. Several protocols described single type stem cell isolation from skin; however, none of them afforded simultaneous isolation of more than one population. Herein, we describe the simultaneous isolation and characterization of three stem cell populations from the dermis and epidermis of murine skin, namely Epidermal Stem Cells (EpiSCs), Skin-derived Precursors (SKPs) and Mesenchymal Stem Cells (MSCs). The simultaneous isolation was possible through a simple protocol based on culture selection techniques. These cell populations are shown to be capable of generating chondrocytes, adipocytes, osteocytes, terminally differentiated keratinocytes, neurons and glia, rendering this protocol suitable for the isolation of cells for tissue replenishment and cell based therapies. The advantages of this procedure are far-reaching since the skin is not only the largest organ in the body, but also provides an easily accessible source of stem cells for autologous graft.

Salivary glands are vital structures responsible for successful tick feeding. The saliva of ticks contains numerous active molecules that participate in several physiological processes. A Kunitz-type factor Xa (FXa) inhibitor, similar to the tissue factor pathway inhibitor (TFPI) precursor, was identified in the salivary gland transcriptome of Amblyomma sculptum ticks. The recombinant mature form of this Kunitz-type inhibitor, named Amblyomin-X, displayed anticoagulant, antiangiogenic, and antitumor properties. Amblyomin-X is a protein that inhibits FXa in the blood coagulation cascade and acts via non-hemostatic mechanisms, such as proteasome inhibition. Amblyomin-X selectively induces apoptosis in cancer cells and promotes tumor regression through these mechanisms. Notably, the cytotoxicity of Amblyomin-X seems to be restricted to tumor cells and does not affect non-tumorigenic cells, tissues, and organs, making this recombinant protein an attractive molecule for anticancer therapy. The cytotoxic activity of Amblyomin-X on tumor cells has led to vast exploration into this protein. Here, we summarize the function, action mechanisms, structural features, pharmacokinetics, and biodistribution of this tick Kunitz-type inhibitor recombinant protein as a promising novel antitumor drug candidate.

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