STAT3 Regulates the Redox Profile in MDA-MB-231 Breast Cancer Cells.

Unbalanced redox status and constitutive STAT3 activation are related to several aspects of tumor biology and poor prognosis, including metastasis and drug resistance. The triple-negative breast cancer (TNBC) is listed as the most aggressive and exhibits the worst prognosis among the breast cancer subtypes. Although the mechanism of reactive oxygen species (ROS) generation led to STAT3 activation is described, there is no data concerning the STAT3 influence on redox homeostasis in TNBC. To address the role of STAT3 signaling in redox balance, we inhibited STAT3 in TNBC cells and investigated its impact on total ROS levels, contents of hydroperoxides, nitric oxide (NO), and total glutathione (GSH), as well as the expression levels of 3-nitrotyrosine (3NT), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), and nuclear factor kappa B (NF-κB)/p65. Our results indicate that ROS levels depend on the STAT3 activation, while the hydroperoxide level remained unchanged, and NO and 3NT expression increased. Furthermore, GSH levels, Nrf2, and NF-κB/p65 protein levels are decreased in the STAT3-inhibited cells. Accordingly, TNBC patients' data from TCGA demonstrated that both STAT3 mRNA levels and STAT3 signature are correlated to NF-κB/p65 and Nrf2 signatures. Our findings implicate STAT3 in controlling redox balance and regulating redox-related genes' expression in triple-negative breast cancer.

Does photobiomodulation alter mitochondrial dynamics?

Mitochondrial dysfunction is one of the leading causes of disease development. Dysfunctional mitochondria limit energy production, increase reactive oxygen species generation, and trigger apoptotic signals. Photobiomodulation is a noninvasive, nonthermal technique involving the application of monochromatic light with low energy density, inducing non-thermal photochemical effects at the cellular level, and it has been used due to its therapeutic potential. This review focuses on the mitochondrial dynamic's role in various diseases, evaluating the possible therapeutic role of low-power lasers (LPL) and light-emitting diodes (LED). Studies increasingly support that mitochondrial dysfunction is correlated with severe neurodegenerative diseases such as Parkinson's, Huntington's, Alzheimer's, and Charcot-Marie-Tooth diseases. Furthermore, a disturbance in mitofusin activity is also associated with metabolic disorders, including obesity and type 2 diabetes. The effects of PBM on mitochondrial dynamics have been observed in cells using a human fibroblast cell line and in vivo models of brain injury, diabetes, spinal cord injury, Alzheimer's disease, and skin injury. Thus, new therapies aiming to improve mitochondrial dynamics are clinically relevant. Several studies have demonstrated that LPL and LED can be important therapies to improve health conditions when there is dysfunction in mitochondrial dynamics.

Lessons from transmissible cancers for immunotherapy and transplant.

The emergence of horizontal transmission of cancer between vertebrates is an issue that interests scientists and medical society. Transmission requires: (i) a mechanism by which cancer cells can transfer to another organism and (ii) a repressed immune response on the part of the recipient. Transmissible tumors are unique models to comprehend the responses and mechanisms mediated by the major histocompatibility complex (MHC), which can be transposed for transplant biology. Here, we discuss the mechanisms involved in immune-mediated tissue rejection, making a parallel with transmissible cancers. We also discuss cellular and molecular mechanisms involved in cancer immunotherapy and anti-rejection therapies.

Twist1 Correlates With Epithelial-Mesenchymal Transition Markers Fibronectin and Vimentin in Adrenocortical Tumors.

BACKGROUND/AIM: Although the knowledge regarding adrenocortical carcinomas (ACC) tumorigenesis has significantly improved during the last decade, it still remains to be completely determined. Epithelial-mesenchymal transition (EMT) is a well described transcription factor induced process, postulated as an essential step toward cancer progression and metastasis development. In this context, Twist1 has been described as the EMT master-regulator. The aim of this study was to assess the association among Twist1, fibronectin, vimentin and E-cadherin gene expression in adrenocortical tumor samples. MATERIALS AND METHODS: Twist1, fibronectin, vimentin and E-cadherin gene expression in 18 adrenal adenomas, 18 ACC, and 24 childhood onset adrenocortical tumors were assessed in formalin-fixed paraffin-embedded tissues. The fold expression was calculated according to the 2ΔCt method. RESULTS: A significant correlation between mRNA levels of Twist1, fibronectin and vimentin was evident. Although their expression was inversely proportional, no association was observed between Twist1 and E-cadherin expression. CONCLUSION: The expression of Twist1, the major regulator of EMT, is directly correlated to the expression of mesenchymal markers fibronectin and vimentin in ACC samples.

Is there a role for epithelial-mesenchymal transition in adrenocortical tumors?

PURPOSE: Epithelial-mesenchymal transition (EMT) is a biological dynamic process by which epithelial cells lose their epithelial phenotype and acquire mesenchymal invasive and migratory characteristics. This has been postulated as an essential step during cancer progression and metastasis. Although this is well described in other tumors, the role of EMT in adrenocortical tumors (ACT) has yet to be addressed. METHODS: The aim of this study was to evaluate the expression of EMT markers e-cadherin, vimentin, and fibronectin, along with EMT-transcription factors (EMT-TFs), TWIST1, SIP1, and SNAIL in 24 adrenocortical carcinoma (ACC), 19 adrenocortical adenomas (ACA), 27 childhood-onset adrenocortical tumors (CAT), and 12 normal adrenal glands. The association of EMT and EMT-TFs with clinical outcomes and pathology features were also evaluated. RESULTS: Cytoplasmic vimentin expression was increased among CAT samples when compared to ACC, ACA, and normal adrenal samples (p < 0.001). There was no difference in e-cadherin and fibronectin expression observed between groups. Nuclear and cytoplasmic expression of TWIST1 and SIP1 was stronger in CAT and ACC vs. ACA and normal tissue samples (all, p < 0.05). ACT, regardless of classification, exhibited increased SNAIL expression when compared to normal tissue (p < 0.05). A significant correlation was observed between vimentin and TWIST1 (r s = 0.44, p < 0.001); SIP1 (r s = 0.51, p < 0.001); and SNAIL (r s = 0.23, p < 0.05). TWIST1 and SIP1 expressions demonstrated a significant correlation (r s = 0.56, p < 0.001). High SIP1 expression was associated with a lower survival rate among ACC cases (p < 0.05). CONCLUSIONS: Vimentin, TWIST1, and SIP1 expressions are increased in aggressive ACT. Therefore, EMT may play a relevant role in adrenal tumorigenesis.

A Novel TP53 Mutation Associated with TWIST1 and SIP1 Expression in an Aggressive Adrenocortical Carcinoma.

Adrenocortical carcinomas (ACC) are very rare tumors related to TP53 mutations mostly in childhood onset cases. Epithelial-mesenchymal transition (EMT) transcription factors TWIST1 and Smad interacting protein 1 (SIP1) are related to poorer outcomes in other malignancies, but their role in ACC is unknown. We describe a case of an advanced metastatic ACC (Weiss-score of 9) in a patient at age 76. After primary tumor resection, mitotane therapy was started as palliation to low-volume liver metastasis. After a 2-year period of stable disease, the patient died due to brain metastasis. Somatic gene sequencing revealed a novel TP53 mutation in DNA extracted from paraffin-embedded tissue, a deletion of 8bp in exon 8 (c.811_818del8; GAGGTGCG/-) in homo or hemizygosis causing a subsequent frameshift and premature stop codon at position 302. Immunohistochemistry of P53 and p-Ser-15 P53 showed absent tumoral staining. In addition, immunohistochemical analysis showed an increased expression of the mesenchymal markers vimentin and fibronectin. At last, EMT transcription factors TWIST1 and SIP1 were also overexpressed in tumoral cells. This case report describes an aggressive ACC with not only a novel somatic mutation, but also a novel International Agency for Research on Cancer database 8 base-pair deletion in TP53 exon 8. In addition, the expression of EMT inducers TWIST1 and SIP1 have been reported for the first time in an ACC case. Further investigation is needed to clarify the biologic significance of this new TP53 mutation and its role in the EMT process.

Targeting Cellular Signaling Pathways in Breast Cancer Stem Cells and its Implication for Cancer Treatment.

Breast cancer is a public health problem both in developing and developed countries. The breast cancer stem cell (BCSC) hypothesis has grown in the cancer research community. These BCSCs comprise of a small subpopulation of cells within the tumor mass which exhibit stem cell-like characteristics and have emerged as being responsible for tumor development, recurrence and metastasis in BC. The complexity of control of gene expression in BCSC is commonly driven by a myriad of signaling pathways triggered by extracellular signals, mutations and epigenetic control. Thus, some signaling pathways have been highlighted in BC, especially those linked to stem cell phenotype, such as nuclear factor-kappa B, signal transducer and activator of transcription 3, wingless-type MMTV integration site family (Wnt)/ß-catenin, Hedgehog and NOTCH. Moreover, these BCSCs can also be influenced by the tumor microenvironment, for instance, hypoxic areas. Given the importance of signaling pathways and tumor microenvironment for breast cancer, this review focuses on the relationship between cellular signaling and BCSCs and its therapeutic implications.