LncRNA-42060 Regulates Tamoxifen Sensitivity and Tumor Development via Regulating the miR-204-5p/SOX4 Axis in Canine Mammary Gland Tumor Cells

Crosstalk of methylation and tamoxifen in breast cancer (Review)

Tamoxifen is a widely used anti‑estrogen drug in the endocrine therapy of breast cancer (BC). It blocks estrogen signaling by competitively binding to estrogen receptor α (ERα), thereby inhibiting the growth of BC cells. However, with the long‑term application of tamoxifen, a subset of patients with BC have shown resistance to tamoxifen, which leads to low overall survival and progression‑free survival. The molecular mechanism of resistance is mainly due to downregulation of ERα expression and abnormal activation of the PI3K/AKT/mTOR signaling pathway. Moreover, the downregulation of targeted gene expression mediated by DNA methylation is an important regulatory mode to control protein expression. In the present review, methylation and tamoxifen are briefly introduced, followed by a focus on the effect of methylation on tamoxifen resistance and sensitivity. Finally, the clinical application of methylation for tamoxifen is described, including its use as a prognostic indicator. Finally, it is hypothesized that when methylation is used in combination with tamoxifen, it could recover the resistance of tamoxifen.

Bringing the Genomic Revolution to Comparative Oncology: Human and Dog Cancers

Dogs are humanity's oldest friend, the first species we domesticated 20,000-40,000 years ago. In this unequaled collaboration, dogs have inadvertently but serendipitously been molded into a potent human cancer model. Unlike many common model species, dogs are raised in the same environment as humans and present with spontaneous tumors with human-like comorbidities, immunocompetency, and heterogeneity. In breast, bladder, blood, and several pediatric cancers, in-depth profiling of dog and human tumors has established the benefits of the dog model. In addition to this clinical and molecular similarity, veterinary studies indicate that domestic dogs have relatively high tumor incidence rates. As a result, there are a plethora of data for analysis, the statistical power of which is bolstered by substantial breed-specific variability. As such, dog tumors provide a unique opportunity to interrogate the molecular factors underpinning cancer and facilitate the modeling of new therapeutic targets. This review discusses the emerging field of comparative oncology, how it complements human and rodent cancer studies, and where challenges remain, given the rapid proliferation of genomic resources. Increasingly, it appears that human's best friend is becoming an irreplaceable component of oncology research.

The Impact of miRNAs on the Efficacy of Tamoxifen in Breast Cancer Treatment: A Systematic Review

Seventy percent of breast cancer patients have an active estrogen receptor. Tamoxifen interferes with estrogen's ability to bind to cancer cells. The most challenging aspect of tamoxifen, however, is that breast cancer cells become resistant to its effects. Some studies have shown that alterations in miRNA expression contribute significantly to drug resistance in breast cancer. Therefore, the present systematic review aims to investigate miRNAs that significantly influence the response to tamoxifen treatment. The present study follows the PRISMA instructions. The Web of Science, PubMed, and Scopus databases were searched to retrieve English articles. The searches were conducted up to September 11, 2022. The search strategy included the terms "Tamoxifen", "Breast Neoplasm", and "MicroRNA". The inclusion criteria of this study are English, original, and experimental studies investigating miRNAs that are effective in the treatment efficacy of tamoxifen. A total of 565 articles were retrieved. After screening, 75 studies met our inclusion criteria. This systematic review study examined 105 miRNAs, of which 44 have a positive effect, and 47 miRNAs inhibit tamoxifen function. Fourteen miRNAs have a controversial effect, ie, some studies show positive and negative effects. The study of miRNAs affecting tamoxifen function in breast cancer patients may facilitate the identification of individuals at higher risk of disease recurrence. Conversely, it can potentially utilize appropriate interventions to defeat drug resistance effectively.

Converting "cold" to "hot": epigenetics strategies to improve immune therapy effect by regulating tumor-associated immune suppressive cells

Significant developments in cancer treatment have been made since the advent of immune therapies. However, there are still some patients with malignant tumors who do not benefit from immunotherapy. Tumors without immunogenicity are called "cold" tumors which are unresponsive to immunotherapy, and the opposite are "hot" tumors. Immune suppressive cells (ISCs) refer to cells which can inhibit the immune response such as tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), regulatory T (Treg) cells and so on. The more ISCs infiltrated, the weaker the immunogenicity of the tumor, showing the characteristics of "cold" tumor. The dysfunction of ISCs in the tumor microenvironment (TME) may play essential roles in insensitive therapeutic reaction. Previous studies have found that epigenetic mechanisms play an important role in the regulation of ISCs. Regulating ISCs may be a new approach to transforming "cold" tumors into "hot" tumors. Here, we focused on the function of ISCs in the TME and discussed how epigenetics is involved in regulating ISCs. In addition, we summarized the mechanisms by which the epigenetic drugs convert immunotherapy-insensitive tumors into immunotherapy-sensitive tumors which would be an innovative tendency for future immunotherapy in "cold" tumor.

Establishment and characterization of cisplatin-resistant cell lines from canine mammary gland tumors

The development of cisplatin resistance is one of the major causes of mammary cancer treatment failure, and is associated with changes in Sox4 gene expression. To investigate the characteristic changes that occur in canine mammary gland tumor (CMGT) cells following the development of acquired cisplatin resistance, along with the relationship between these changes and the Sox4 gene. We constructed cisplatin-resistant cell line, CHMpCIS, from the cell line CHMp, which was isolated from the primary lesion of a malignant CMGT. The biological characteristics of these cells were examined by Western blot analysis, Transwell assays, and mammosphere formation assays. Compared to CHMp cells, CHMpCIS cells exhibited elevated cisplatin resistance, apoptotic escape ability, enhanced epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) features, in addition to over-activation of the Wnt/β-catenin signaling pathway and increased Sox4 protein. In CMGT cases, CMGT tissues (CMGTT) expressed higher levels of Sox4 protein and mRNA compared to adjacent tissues (CAMGTT). We found that these changes were inhibited by silencing of Sox4 expression in CHMpCIS cells. Furthermore, activation of the Wnt/β-catenin signaling pathway increased Sox4 expression levels through a positive feedback loop. These results suggested that CHMpCIS cells circumvented the damage caused by cisplatin through altering the expression of the Sox4 gene and activating the Wnt/β-catenin pathway, thereby changing the cellular biological characteristics.

Long Non-Coding RNA as a Potential Biomarker for Canine Tumors

Cancer is the leading cause of death in both humans and companion animals. Long non-coding RNA (lncRNA) plays a crucial role in the progression of various types of cancers in humans, involving tumor proliferation, metastasis, angiogenesis, and signaling pathways, and acts as a potential biomarker for diagnosis and targeted treatment. However, research on lncRNAs related to canine tumors is in an early stage. Dogs have long been considered a promising natural model for human disease. This article summarizes the molecular function of lncRNAs as novel biomarkers in various types of canine tumors, providing new insights into canine tumor diagnosis and treatment. Further research on the function and mechanism of lncRNAs is needed, which will benefit both human and veterinary medicine.

Molecular Mechanisms of Anti-Estrogen Therapy Resistance and Novel Targeted Therapies

Breast cancer (BC) is the most commonly diagnosed cancer in women, constituting one-third of all cancers in women, and it is the second leading cause of cancer-related deaths in the United States. Anti-estrogen therapies, such as selective estrogen receptor modulators, significantly improve survival in estrogen receptor-positive (ER+) BC patients, which represents about 70% of cases. However, about 60% of patients inevitably experience intrinsic or acquired resistance to anti-estrogen therapies, representing a major clinical problem that leads to relapse, metastasis, and patient deaths. The resistance mechanisms involve mutations of the direct targets of anti-estrogen therapies, compensatory survival pathways, as well as alterations in the expression of non-coding RNAs (e.g., microRNA) that regulate the activity of survival and signaling pathways. Although cyclin-dependent kinase 4/6 and phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) inhibitors have significantly improved survival, the efficacy of these therapies alone and in combination with anti-estrogen therapy for advanced ER+ BC, are not curative in advanced and metastatic disease. Therefore, understanding the molecular mechanisms causing treatment resistance is critical for developing highly effective therapies and improving patient survival. This review focuses on the key mechanisms that contribute to anti-estrogen therapy resistance and potential new treatment strategies alone and in combination with anti-estrogen drugs to improve the survival of BC patients.

Epigenetic alterations in canine mammary cancer

In dogs, mammary cancer is the most common tumor type, especially in unspayed females. As in humans, this type of cancer has spontaneous development and is influenced by several risk factors, such as age and hormonal exposure in addition to genetic and epigenetic factors. Epigenetic mechanisms are responsible for gene expression modulation without alterations in the DNA sequence and include but are not limited to DNA methylation, histone modifications, and noncoding RNAs. Epigenetic patterns are known to influence a variety of biological mechanisms, such as cellular differentiation and development, and dysregulations of those patterns may result in several diseases, such as cancer. In this respect, this review summarizes the main findings concerning epigenetic alterations in canine mammary cancer, their relationship with the carcinogenic process, and their use as diagnostic and prognostic markers.

Tumor imaging and photothermal therapy in second near infrared window: A systematic review and meta-analysis

Background

Second near-infrared window (NIR-II, 1000-1700 nm) technology for tumor imaging and photothermal therapy (PTT) is an innovative method for tumor diagnosis and treatment. The NIR-II probe can specifically identify tumor cells, and effectively convert light energy into heat energy under the irradiation of NIR laser, thus achieving the integration of non-invasive tumor diagnosis and treatment. In the present study, we conducted a systematic review and meta-analysis of preclinical investigations to corroborate the efficacy and safety of photothermal therapy.

Methods

Relevant preclinical data were retrieved by searching PubMed, Web of Science, CNKI, WANFANG and VIP information databases. And the acquired data were analyzed by RevMan Version 5.3 software.

Results

According to the inclusion criteria, forty-two articles relating to NIR-II tumor imaging and PTT were recruited for further in-depth analysis. The NIR-II photoacoustic and fluorescence imaging could quickly and accurately identify tumor in mice, manifesting higher signal intensity on tumor site than that of normal tissue. After PTT, the tumor volume of mice decreased miraculously [RR=8.49, 95%CI (4.64, 15.55), P<0.00001], and even disappeared completely [RR=7.01, 95%CI (3.04, 16.13), P<0.00001] with no potential risk of affecting the blood routine.

Conclusions

PTT guided by NIR-II imaging can effectively diagnose the tumor lesion and eliminate it with the advantages of non-invasive and higher biosafety.

LncRNA: a new perspective on the study of neurological diseases

Long non-coding RNAs (lncRNAs) are a class of non-coding RNA with a length greater than 200 nt. It has a mRNA-like structure, formed by splicing after transcription, and contains a polyA tail and a promoter, of whom promoter plays a role by binding transcription factors. LncRNAs' sequences are low in conservation, and other species can only find a handful of the same lncRNAs as humans, and there are different splicing ways during the differentiation of identical species, with spatiotemporal expression specificity. With developing high-throughput sequencing and bioinformatics, found that more and more lncRNAs associated with nervous system disease. This article deals with the regulation of certain lncRNAs in the nervous system disease, by mean of to understand its mechanism of action, and the pathogenesis of some neurological diseases have a fresh understanding, deposit a foundation for resulting research and clinical treatment of disease.

LncRNA Expression Profiles in Canine Mammary Tumors Identify lnc34977 as a Promoter of Proliferation, Migration and Invasion of Canine Mammary Tumor Cells

Canine mammary tumor (CMT) is the most common tumor in canines after skin tumors. Long noncoding RNAs (lncRNAs) have crucial roles in human breast tumor initiation and progression, but the role of lncRNAs in canine mammary tumors is unclear. We analyzed the expression profiles of canine mammary tumors and their adjacent non-neoplastic tissue to explore abnormally expressed lncRNAs. LncRNA expression was detected by qRT–PCR. After overexpression of lnc40589 and knockdown of lnc34977 in CMT cells, CCK-8, colony formation, wound healing and Transwell assays were used to assess the proliferation, migration and invasive ability of canine mammary tumor cells. We also established a mammary tumor-bearing nude mouse model. GO analysis and KEGG pathway analysis demonstrated that the differentially expressed lncRNAs were closely related to the mammary tumor. lnc40589 was significantly upregulated and lnc34977 was significantly downregulated in CMTs. In addition, lnc40589 inhibits cell proliferation, migration and invasion, while lnc34977 promotes cell proliferation, migration and invasion. In addition, lnc34977 promotes the development of mammary tumors in animals. Taken together, our study results reveal the lncRNA expression profiles in CMTs and indicate that lnc34977 promotes the development of CMT both in cell culture and in vivo.