Altered Expression of TRIM Proteins-Inimical Outcome and Inimitable Oncogenic Function in Breast Cancer with Diverse Carcinogenic Hallmarks

Deregulation of ubiquitin-mediated degradation of oncogene products or tumor suppressors appears to be implicated in the genesis of carcinomas, according to new clinical findings. Conferring to recent research, some members of the tripartite motif (TRIM) proteins (a subfamily of the RING type E3 ubiquitin ligases) act as significant carcinogenesis regulators. Intracellular signaling, development, apoptosis, protein quality control, innate immunity, autophagy, and carcinogenesis are all regulated by TRIM family proteins, the majority of which have E3 ubiquitin ligase activity. The expression of TRIMs in tumors is likely to be related to the formation and/or progression of the disease, and TRIM expression could be used to predict cancer prognosis. Breast cancer is the most common malignancy in women and also the leading cause of death. TRIM family proteins have unique, vital activities, and their dysregulation, such as TRIM 21, promotes breast cancer, according to growing evidence. Many TRIM proteins have been identified as important cancer biomarkers, with decreased or elevated levels of expression. TRIM29 functions as a hypoxia-induced tumor suppressor gene, revealing a new molecular mechanism for ATM-dependent breast cancer suppression. In breast cancer cells, the TRIM28-TWIST1-EMT axis exists, and TRIM28 enhances breast cancer metastasis by stabilizing TWIST1 and thereby increasing epithelial-to-mesenchymal transition. Interestingly, many TRIM proteins are involved in the control of p53, and many TRIM proteins are likewise regulated by p53, according to current research. Furthermore, TRIMs linked to specific tumors may aid in the creation of innovative TRIM-targeted cancer treatments. This review focuses on TRIM proteins that are involved in tumor development, progression, and clinical significance in breast cancer.

Compression enhances invasive phenotype and matrix degradation of breast Cancer cells via Piezo1 activation

Background Uncontrolled growth in solid breast cancer generates mechanical compression that may drive the cancer cells into a more invasive phenotype, but little is known about how such compression affects the key events and corresponding regulatory mechanisms associated with invasion of breast cancer cells including cellular behaviors and matrix degradation. Results Here we show that compression enhanced invasion and matrix degradation of breast cancer cells. We also identified Piezo1 as the putative mechanosensitive cellular component that transmitted compression to not only enhance the invasive phenotype, but also induce calcium influx and downstream Src signaling. Furthermore, we demonstrated that Piezo1 was mainly localized in caveolae, and both Piezo1 expression and compression-enhanced invasive phenotype of the breast cancer cells were reduced when caveolar integrity was compromised by either knocking down caveolin1 expression or depleting cholesterol content. Conclusions Taken together, our data indicate that mechanical compression activates Piezo1 channels to mediate enhanced breast cancer cell invasion, which involves both cellular events and matrix degradation. This may be a critical mechanotransduction pathway during breast cancer metastasis, and thus potentially a novel therapeutic target for the disease.

Metabolite profiling reveals a connection between aldehyde dehydrogenase 1A3 and GABA metabolism in breast cancer metastasis

Introduction Aldehyde dehydrogenase 1A3 (ALDH1A3) is a cancer stem cell (CSC) marker and in breast cancer it is associated with triple-negative/basal-like subtypes and aggressive disease. Studies on the mechanisms of ALDH1A3 in cancer have primarily focused on gene expression changes induced by the enzyme; however, its effects on metabolism have thus far been unstudied and may reveal novel mechanisms of pathogenesis. Objective Determine how ALDH1A3 alters the metabolite profile in breast cancer cells and assess potential impacts. Method Triple-negative MDA-MB-231 tumors and cells with manipulated ALDH1A3 levels were assessed by HPLC–MS metabolomics and metabolite data was integrated with transcriptome data. Mice harboring MDA-MB-231 tumors with or without altered ALDH1A3 expression were treated with γ-aminobutyric acid (GABA) or placebo. Effects on tumor growth, and lungs and brain metastasis were quantified by staining of fixed thin sections and quantitative PCR. Breast cancer patient datasets from TCGA, METABRIC and GEO were used to assess the co-expression of GABA pathway genes with ALDH1A3. Results Integrated metabolomic and transcriptome data identified GABA metabolism as a primary dysregulated pathway in ALDH1A3 expressing breast tumors. Both ALDH1A3 and GABA treatment enhanced metastasis. Patient dataset analyses revealed expression association between ALDH1A3 and GABA pathway genes and corresponding increased risk of metastasis. Conclusion This study revealed a novel pathway affected by ALDH1A3, GABA metabolism. Like ALDH1A3 expression, GABA treatment promotes metastasis. Given the clinical use of GABA mimics to relieve chemotherapy-induced peripheral nerve pain, further study of the effects of GABA in breast cancer progression is warranted.

Dissecting RAS Oncogene-Induced Kinome Involved in Breast Cancer Metastasis

Background and Hypothesis: The RAS and PI3K-AKT-mTOR signaling pathways are often dysregulated in cancer. RAS pathway alterations, however, are more common in breast cancer metastasis. The laboratory’s recently developed model system demonstrated the ability of RAS but not PIK3CA-induced signals in promoting metastasis of breast cancer. Unbiased kinome analyses of isogenic RAS-transformed primary tumor and metastatic cells and PIK3CA-transformed primary tumor cells enabled identification of RAS-activated kinome, which included FER, PAK4, LIMK1, PIK3CD and Casein Kinase 2 (CK2). We hypothesized that therapeutic targeting of these kinases may reduce breast cancer metastasis. As a proof-of-principle, the effect of the CK2 inhibitor Silmitasertib, which is in clinical trial for COVID-19 and refractory multiple myeloma, was tested. Experimental Design: The study included four isogenic cell lines: “normal” (KTB34-hTERT), PIK3CA-transformed (TKTB34-PIK3CA), RAS-transformed (TKTB34-RAS), and RAS-transformed cells metastasized to lungs (MKTB34-RAS). Active kinomes in these cells were identified using phospho-proteomics and functional kinome profiling using multiplexed kinase inhibitor beads. Expression levels of FER, PAK4, LIMK1, and PIK3CD kinases were compared through Western Blot using the phospho-antibodies as an indicator of kinase activation. Sensitivity to Silmitasertib was measured using the BrdU Cell Proliferation Assay. Results: FER, PAK4, LIMK1, and PIK3CD were all overexpressed in the TKTB34-RAS and MKTB34-RAS cells compared to KTB34-hTERT and TKTB34-PIK3CA cells. The tested concentration range for Silmitasertib (500 nM to 5 µM) was ineffective in killing the RAS-transformed cells and was overly toxic to “normal” cells. Conclusion and Potential Impact: FER, PAK4, LIMK1, PIK3CD, and CK2 are potential therapeutic targets for breast cancer metastasis. However, Silmitasertib may not be a good candidate as it is more toxic to “normal” cells compared to cancer cells. The isogenic “normal” and transformed cell line model system described here may help to discover new targets and drugs that kill cancer but not normal cells.