Isolation and characterization of adult mammary stem cells from breast cancer-adjacent tissues

Navigating challenges: optimising methods for primary cell culture isolation

Primary cell lines are invaluable for exploring cancer biology and investigating novel treatments. Despite their numerous advantages, primary cultures are laborious to obtain and maintain in culture. Hence, established cell lines are still more common. This study aimed to evaluate a range of techniques for isolating primary breast cancer cultures, employing distinct enzymatic compositions, incubation durations, and mechanical approaches, including filtration. Out of several protocols, we opted for a highly effective method (Method 5) that gave rise to a primary cell culture (BC160). This method combines mechanical disaggregation and enzymatic digestion with hyaluronidase and collagenase. Moreover, the paper addresses common issues in isolating primary cultures, shedding light on the struggle against fibroblasts overgrowing cancer cell populations. To make primary cell lines a preferred model, it is essential to elaborate and categorise isolation methods, develop approaches to separate heterogeneous cultures and investigate factors influencing the establishment of primary cell lines.

From Donor to the Lab: A Fascinating Journey of Primary Cell Lines

Primary cancer cell lines are ex vivo cell cultures originating from resected tissues during biopsies and surgeries. Primary cell cultures are objects of intense research due to their high impact on molecular biology and oncology advancement. Initially, the patient-derived specimen must be subjected to dissociation and isolation. Techniques for tumour dissociation are usually reliant on the organisation of connecting tissue. The most common methods include enzymatic digestion (with collagenase, dispase, and DNase), chemical treatment (with ethylene diamine tetraacetic acid and ethylene glycol tetraacetic acid), or mechanical disaggregation to obtain a uniform cell population. Cells isolated from the tissue specimen are cultured as a monolayer or three-dimensional culture, in the form of multicellular spheroids, scaffold-based cultures (i.e., organoids), or matrix-embedded cultures. Every primary cell line must be characterised to identify its origin, purity, and significant features. The process of characterisation should include different assays utilising specific (extra- and intracellular) markers. The most frequently used approaches comprise immunohistochemistry, immunocytochemistry, western blot, flow cytometry, real-time polymerase chain reaction, karyotyping, confocal microscopy, and next-generation sequencing. The growing body of evidence indicates the validity of the usage of primary cancer cell lines in the formulation of novel anti-cancer treatments and their contribution to drug development.

miR-296-5p suppresses stem cell potency of hepatocellular carcinoma cells via regulating Brg1/Sall4 axis

Epithelial-mesenchymal transition (EMT), a pivotal event during cancer progression such as relapse and metastasis, is positively correlated with the stemness potency of tumor cells. Our previous study showed that miR-296-5p attenuated EMT program of hepatocellular carcinoma cells (HCC) through NRG1/ERBB2/ERBB3 signaling. In the present study, we uncovered that miR-296-5p was able to inhibit the stemness potency of HCC by decreasing the number and size of tumorspheres, downregulating the expression of CSC biomarkers and hampering the ability of tumorigenesis in NOD/SCID mice. Brahma-related gene-1 (Brg1), as the target protein of miR-296-5p detected by bioinformatics methods, activates a series of downstream cascades through directly binding to Sall4 promoter and enhancing Sall4 transcription. Importantly, the higher expressions of Brg1 and Sall4 in tumor tissues of HCC patients suggest poorer prognoses after surgical extraction. In conclusion, miR-296-5p exerts an inhibitory effect on stemness potency of HCC cells via Brg1/Sall4 axis.

Identification of tRNA-derived small noncoding RNAs as potential biomarkers for prediction of recurrence in triple-negative breast cancer

Triple‐negative breast cancer (TNBC), an intrinsic subtype of breast cancer, is characterized by aggressive pathology and shorter overall survival. Yet there is no effective therapy for these patients. Breast cancer stem cells (BCSCs) in TNBC may account for treatment failure. It is urgent to identify new therapeutic targets for TNBC. tRNA‐derived small noncoding RNAs (tDRs) represent a new class of small noncoding RNAs (sncRNA), which have been reported in some human diseases and biological processes. However, there is no detailed information about the relationship between tDRs and BCSCs. In this study, a population of CD44⁺/CD24^−/low cells was isolated and identified by reliable BCSC surface markers. tDR expression profiles in TNBC and non‐TNBC CSCs were performed by RNA sequencing. A total of 1327 differentially expressed tDRs contained 18 upregulated and 54 downregulated in TNBC group. Furthermore, the selected tDRs were validated by quantitative reverse transcription‐polymerase chain reaction (qRT‐PCR). tDR‐000620 expression level was consistently lower in TNBC cell lines CSCs (all P < 0.05) and serum samples (t = 2.597, P = 0.013). tDR‐000620 expression was significant association with age (P = 0.018), node status (P = 0.026) and local recurrence (P = 0.019) by chi‐square test. Kaplan‐Meier method with log‐rank test for comparison of recurrence curves. The results showed that the tDR‐000620 expression (P = 0.002) and node status (P = 0.001) group were statistically significant with recurrence‐free survival. Furthermore, multivariate Cox regression demonstrated that lymphatic metastasis (HR, 3.616; 95% CI, 1.234‐10.596; P = 0.019) and low tDR‐000620 expression (HR, 0.265; 95% CI, 0.073‐0.959; P = 0.043) were two independent adverse predictive factors for recurrence‐free survival. Finally, we found that tDR‐000620 participated in some important biological processes though GO and KEGG analysis. Taken together, our study reveals the expression profiles of tDRs in TNBC and non‐TNBC CSCs. It offers helpful information to understand the tDR‐000620 expression is responsible for the aggressive phenotype of BCSCs. It may provide predictive biomarkers and therapeutic targets for TNBC recurrence.