Expression distribution of cancer stem cells, epithelial to mesenchymal transition, and telomerase activity in breast cancer and their association with clinicopathologic characteristics

Association between Obesity, Race or Ethnicity, and Luminal Subtypes of Breast Cancer

Luminal breast cancers are the most common genomic subtype of breast cancers where Luminal A cancers have a better prognosis than Luminal B. Exposure to sex steroids and inflammatory status due to obesity are key contributors of Luminal tumor development. In this study, 1928 patients with Luminal A breast cancer and 1610 patients with Luminal B breast cancer were compared based on body mass index (BMI), age, race, menopausal status, and expressed receptors (i.e., estrogen (ER), progesterone (PR), and human epidermal growth factor receptor 2 (HER2)). Patients with Luminal B tumors had a significantly higher mean BMI (Δ = 0.69 kgm−2 [0.17, 1.21], p = 0.010) versus Luminal A. Interestingly, the risks of Luminal B tumors were higher among Black/African American patients versus White and Hispanic patients (p < 0.001 and p = 0.001, respectively). When controlled for each other, Black/African American race (p < 0.001) and increased BMI (p = 0.008) were associated with increased risks of Luminal B carcinoma, while postmenopausal status was associated with a decreased risk (p = 0.028). Increased BMI partially mediated the strong association between Black/African American race and the risk of Luminal B carcinoma. Thus, Black/African American race along with obesity seem to be associated with an increased risk of more aggressive Luminal B breast carcinomas.

Evaluation of CD44s, CD44v6, CXCR2, CXCL1, and IL-1β in Benign and Malignant Tumors of Salivary Glands

BACKGROUND

Several studies have reported an association between high expression of CD44 in different types of cancer. However, no study has reported a link among CD44 expression, other biomarkers, and the aggressiveness of salivary gland tumors.

METHODS

A total of 38 specimens were obtained from non-tumorous salivary glands, benign and malignant tumors in salivary glands. Immunohistochemical analyses of CD44s, CD44v6, IL-1β, CXCL1, and CXCR2 were performed, and the area of positive cells was assessed.

RESULTS

We found that both CD44s and CXCR2 expression were increased in the benign and malignant groups. CD44v6 was also increased in both groups, but it had the highest level in the malignant group. IL-1β was the only biomarker that increased significantly in the malignant group in comparison to the other two groups.

CONCLUSIONS

CD44s, CD44v6, CXCR2, and IL-1β expressions were found to be higher in salivary gland tumors. However, IL-1β alone may play a crucial role in the aggressiveness of salivary gland tumors as this cytokine was expressed only in the malignant group with high expression associated with high-grade malignancy.

Identification of potential therapeutic target of naringenin in breast cancer stem cells inhibition by bioinformatics and in vitro studies

Cancer therapy is a strategic measure in inhibiting breast cancer stem cell (BCSC) pathways. Naringenin, a citrus flavonoid, was found to increase breast cancer cells' sensitivity to chemotherapeutic agents. Bioinformatics study and 3D tumorsphere in vitro modeling in breast cancer (mammosphere) were used in this study, which aims to explore the potential therapeutic targets of naringenin (PTTNs) in inhibiting BCSCs. Bioinformatic analyses identified direct target proteins (DTPs), indirect target proteins (ITPs), naringenin-mediated proteins (NMPs), BCSC regulatory genes, and PTTNs. The PTTNs were further analyzed for gene ontology, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, protein-protein interaction (PPI) networks, and hub protein selection. Mammospheres were cultured in serum-free media. The effects of naringenin were measured by MTT-based cytotoxicity, mammosphere forming potential (MFP), colony formation, scratch wound-healing assay, and flow cytometry-based cell cycle analyses and apoptosis assays. Gene expression analysis was performed using real-time quantitative polymerase chain reaction (q-RT PCR). Bioinformatics analysis revealed p53 and estrogen receptor alpha (ERα) as PTTNs, and KEGG pathway enrichment analysis revealed that TGF-ß and Wnt/ß-catenin pathways are regulated by PTTNs. Naringenin demonstrated cytotoxicity and inhibited mammosphere and colony formation, migration, and epithelial to mesenchymal transition in the mammosphere. The mRNA of tumor suppressors P53 and ERα were downregulated in the mammosphere, but were significantly upregulated upon naringenin treatment. By modulating the P53 and ERα mRNA, naringenin has the potential of inhibiting BCSCs. Further studies on the molecular mechanism and formulation of naringenin in BCSCs would be beneficial for its development as a BCSC-targeting drug.

Molecular and cellular paradigms of multidrug resistance in cancer

BACKGROUND

The acquisition of resistance to chemotherapy is a major hurdle in the successful application of cancer therapy. Several anticancer approaches, including chemotherapies, radiotherapy, surgery and targeted therapies are being employed for the treatment of cancer. However, cancer cells reprogram themselves in multiple ways to evade the effect of these therapies, and over a period of time, the drug becomes inactive due to the development of multi-drug resistance (MDR). MDR is a complex phenomenon where malignant cells become insensitive to anticancer drugs and attain the ability to survive even after several exposures of anticancer drugs. In this review, we have discussed the molecular and cellular paradigms of multidrug resistance in cancer.

RECENT FINDINGS

An Extensive research in cancer biology revealed that drug resistance in cancer is the result of perpetuated intracellular and extracellular mechanisms such as drug efflux, drug inactivation, drug target alteration, oncogenic mutations, altered DNA damage repair mechanism, inhibition of programmed cell death signaling, metabolic reprogramming, epithelial mesenchymal transition (EMT), inherent cell heterogeneity, epigenetic changes, redox imbalance, or any combination of these mechanisms. An inevitable cross-link between inflammation and drug resistance has been discussed. This review provided insight molecular mechanism to understand the vulnerabilities of cancer cells to develop drug resistance.

CONCLUSION

MDR is an outcome of interplays between multiple intricate pathways responsible for the inactivation of drug and development of resistance. MDR is a major obstacle in regimens of successful application of anti-cancer therapy. An improved understanding of the molecular mechanism of multi drug resistance and cellular reprogramming can provide a promising opportunity to combat drug resistance in cancer and intensify anti-cancer therapy for the upcoming future.

Association of CD44 and CD24 phenotype with lymph node metastasis and survival in triple-negative breast cancer

BACKGROUND

CD44⁺CD24^-/low phenotypes are associated with poor outcome of triple-negative breast cancer (TNBC); however, the role of the CD44⁺CD24^-/low phenotype in lymph node metastasis and survival has not been fully understood in TNBC.

METHODS

A total of 51 TNBC patients were included. CD44 and CD24 expression was determined using immunohistochemistry by which CD44 and CD24 were double-immunostained. Overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan-Meier method.

RESULTS

The proportion of the CD44⁺CD24^-/low phenotype was 33.3% in TNBC specimens without lymph node metastases and 69.0% in those with lymph node metastases. In addition, the CD44⁺CD24^-/low phenotype correlated significantly with tumor size, histologic classification, TNM stage, and lymph node metastasis (P < 0.05). The CD44⁺CD24^-/low phenotype was detected in 69.0% of TNBC patients with lymph node metastases, and 51.7% of TNBC patients without lymph node metastases. In TNBC patients without lymph node metastases, the median DFS and OS were 18.2 and 28 months in cases with a CD44⁺CD24^-/low phenotype and 26.5 and 42.5 months in those without a CD44⁺CD24^-/low phenotype (P < 0.05), and in TNBC patients with lymph node metastases, the median DFS and OS were 17.2 and 25.7 months in cases with a CD44⁺CD24^-/low phenotype and 24.5 and 39.3 months in those without a CD44⁺CD24^-/low phenotype, respectively (P < 0.05).

CONCLUSIONS

CD44 and CD24 are independent prognostic markers for patients with TNBC. The CD44⁺CD24^-/low phenotype correlates with more aggressive clinicopathologic features and is strongly associated with poor prognosis in patients with TNBC.

The effect of centromere protein U silencing by lentiviral mediated RNA interference on the proliferation and apoptosis of breast cancer

Centromere protein U (CENPU) is a novel transcriptional repressor that is associated with different types of cancer. However, its function in breast cancer is poorly understood. In the present study, it was identified that CENPU was highly expressed in breast cancer tissues compared with expression in normal breast tissues (P=0.001). Furthermore, the CENPU mRNA level in tumors was often elevated, compared with the matched adjacent normal breast cancer tissue specimens in the dataset from The Cancer Genome Atlas database (n=106; P<0.001). To understand the function of CENPU in human breast carcinogenesis, its effects on the proliferation, apoptosis and cell cycle progression of MDA-MB-231 cells were examined using the lentiviral-mediated CENPU knockdown approach. The RNA and protein expression levels in the transfected cells were monitored using reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. The mRNA and protein expression levels of the CENPU gene were significantly lower in the CENPU-shRNA transfected cells than in the control (P<0.01), indicating successful gene expression knockdown. Post-transfection, cell counting and MTT analysis revealed that the proliferation activity was significantly suppressed in CENPU knockdown cells relative to the control (P<0.01). Additionally, fluorescence activated cell sorting analysis revealed that the (G2+S) phase fraction was significantly declined in CENPU knockdown cells relative to the control; while the G1 phase fraction was significantly increased (P<0.01) and the percentage of the apoptotic cells was significantly increased (P<0.01). In conclusion, downregulation of CENPU gene expression may inhibit cell proliferation and cell cycle progression, and increase the apoptosis of the breast cancer cells. These results suggested a possible function of this protein in breast cancer pathogenesis and prognosis.

miR-340 and ZEB1 negative feedback loop regulates TGF-β- mediated breast cancer progression

MicroRNAs act as key regulators in carcinogenesis and progression in various cancers. In present study, we explored the role of miR-340 in the breast cancer progression. Our results showed that overexpression of miR-340 inhibits breast cancer cell proliferation and invasion, whereas depletion of miR-340 promotes breast cancer progression. Molecularly, ZEB1 was identified as a target gene of miR-340 and miR-340 suppressed the expression of ZEB1 by directly binding to the 3′-UTR of ZEB1. Furthermore, ZEB1 transcriptionally suppresses miR-340 expression. The negative feedback loop regulated TGF-β-mediated breast cancer progression. In conclusion, our data suggested that miR-340 acted as a tumor suppressor in breast cancer progression.

HER2 Overexpression Triggers an IL1α Proinflammatory Circuit to Drive Tumorigenesis and Promote Chemotherapy Resistance

Systemic inflammation in breast cancer correlates with poor prognosis, but the molecular underpinnings of this connection are not well understood. In this study, we explored the relationship between HER2 overexpression, inflammation, and expansion of the mammary stem/progenitor and cancer stem-like cell (CSC) population in breast cancer. HER2-positive epithelial cells initiated and sustained an inflammatory milieu needed to promote tumorigenesis. HER2 induced a feedforward activation loop of IL1α and IL6 that stimulated NFκB and STAT3 pathways for generation and maintenance of breast CSC. In mice, Il1a genetic deficiency delayed MMTV-Her2-induced tumorigenesis and reduced inflammatory cytokine expression as well as CSC in primary tumors. In clinical specimens of human breast tumor tissues, tissue microarray analysis revealed a strong positive correlation between IL1α/IL6 expression and CSC-positive phenotype. Pharmacologic blockade of IL1α signaling reduced the CSC population and improved chemotherapeutic efficacy. Our findings suggest new therapeutic or prevention strategies for HER2-positive breast cancers.Significance: IL1α signaling driven by HER2 promotes chronic inflammation needed to support cancer stem-like cell maintenance in HER2-positive breast cancers. Cancer Res; 78(8); 2040-51. ©2018 AACR.

Drug Resistance Driven by Cancer Stem Cells and Their Niche

Drug resistance represents one of the greatest challenges in cancer treatment. Cancer stem cells (CSCs), a subset of cells within the tumor with the potential for self-renewal, differentiation and tumorigenicity, are thought to be the major cause of cancer therapy failure due to their considerable chemo- and radioresistance, resulting in tumor recurrence and eventually metastasis. CSCs are situated in a specialized microenvironment termed the niche, mainly composed of fibroblasts and endothelial, mesenchymal and immune cells, which also play pivotal roles in drug resistance. These neighboring cells promote the molecular signaling pathways required for CSC maintenance and survival and also trigger endogenous drug resistance in CSCs. In addition, tumor niche components such as the extracellular matrix also physically shelter CSCs from therapeutic agents. Interestingly, CSCs contribute directly to the niche in a bilateral feedback loop manner. Here, we review the recent advances in the study of CSCs, the niche and especially their collective contribution to resistance, since increasingly studies suggest that this interaction should be considered as a target for therapeutic strategies.

Inhibition of RAB1A suppresses epithelial-mesenchymal transition and proliferation of triple-negative breast cancer cells

RAB1A acts as an oncogene in various cancers, and emerging evidence has verified that RAB1A is an mTORC1 activator in hepatocellular and colorectal cancer, but the role of RAB1A in breast cancer remains unclear. In this investigation, RAB1A siRNA was successfully transfected in MDA-MB-231 and BT-549 human triple-negative breast cancer cells, and verified by real‑time quantitative polymerase chain reaction and western blotting. Then, MTT cell proliferation, colony formation, cell invasion and wound healing assays were performed to characterize the function of RAB1A in the breast cancer cell lines. Downregulation of RAB1A inhibited cellular growth, cell migration, cell invasion and cell epithelial-mesenchymal transition. Furthermore, compared with NC siRNA transfected cells, RAB1A siRNA transfected breast cancer cells inhibited the phosphorylation of S6K1, the effector molecular of mTORC1. Collectively, our data suggested that RAB1A acts as an oncogene by regulating cellular proliferation, growth, invasion and metastasis via activation of mTORC1 pathway in triple-negative breast cancer.

Molecular characterization of CD44+/CD24-/Ck+/CD45- cells in benign and malignant breast lesions

Breast cancer epithelial cells with the CD44⁺/CD24^-/low phenotype possess tumor-initiating cells and epithelial-mesenchymal transition (EMT) capacity. Massive parallel sequencing can be an interesting approach to deepen the molecular characterization of these cells. We characterized CD44⁺/CD24^-/cytokeratin(Ck)⁺/CD45^- cells isolated through flow cytometry from 43 biopsy and 6 mastectomy samples harboring different benign and malignant breast lesions. The Ion Torrent Ampliseq Cancer Hotspot panel v2 (CHPv2) was used for the identification of somatic mutations in the DNA extracted from isolated CD44⁺/CD24^-/Ck⁺/CD45^- cells. E-Cadherin and vimentin immunohistochemistry was performed on sections from the corresponding formalin-fixed, paraffin-embedded (FFPE) blocks. The percentage of CD44⁺/CD24^-/Ck⁺/CD45^- cells increased significantly from non-malignant to malignant lesions and in association with a significant increase in the expression of vimentin. Non-malignant lesions harbored only a single-nucleotide polymorphism (SNP). Mutations in the tumor suppressor p53 (TP53), NOTCH homolog 1 (NOTCH1), phosphatase and tensin homolog (PTEN), and v-akt murine thymoma viral oncogene homolog 1 (AKT1) genes were found in isolated CD44⁺/CD24^-/Ck⁺/CD45^- cells from ductal carcinomas in situ (DCIS). Additional mutations in the colony-stimulating factor 1 receptor (CSF1R), ret proto-oncogene (RET), and TP53 genes were also identified in invasive ductal carcinomas (IDCs). The use of massive parallel sequencing technology for this type of application revealed to be extremely effective even when using small amounts of DNA extracted from a low number of cells. Additional studies are now required using larger cohorts to design an appropriate mutational profile for this phenotype.

Radiation induces the generation of cancer stem cells: A novel mechanism for cancer radioresistance

Radioresistance remains a major obstacle for the radiotherapy treatment of cancer. Previous studies have demonstrated that the radioresistance of cancer is due to the existence of intrinsic cancer stem cells (CSCs), which represent a small, but radioresistant cell subpopulation that exist in heterogeneous tumors. By contrast, non-stem cancer cells are considered to be radiosensitive and thus, easy to kill. However, recent studies have revealed that under conditions of radiation-induced stress, theoretically radiosensitive non-stem cancer cells may undergo dedifferentiation subsequently obtaining the phenotypes and functions of CSCs, including high resistance to radiotherapy, which indicates that radiation may directly result in the generation of novel CSCs from non-stem cancer cells. These findings suggest that in addition to intrinsic CSCs, non-stem cancer cells may also contribute to the relapse and metastasis of cancer following transformation into CSCs. This review aims to investigate the radiation-induced generation of CSCs, its association with epithelial-mesenchymal transition and its significance with regard to the radioresistance of cancer.

Diagnostic Implication and Clinical Relevance of Ancillary Techniques in Clinical Pathology Practice

Hematoxylin–eosin-stained slide preparation is one of the most durable techniques in medicine history, which has remained unchanged since implemented. It allows an accurate microscopic diagnosis of the vast majority of tissue samples. In many circumstances, this technique cannot answer all the questions posed at the initial diagnostic level. The pathologist has always been looking for additional ancillary techniques to answer pending questions. In our daily histopathology practice, we referred to those techniques as special stains, but nowadays, they are more than stains and are collectively called ancillary tests. They include a wide range of techniques starting from histochemical stains and ending in one or more advanced techniques, such as immunohistochemistry, immunofluorescence, molecular studies, cytogenetic studies, electron microscopy, flow cytometry, and polymerase chain reaction.

Diversity of Breast Carcinoma: Histological Subtypes and Clinical Relevance

Mammary carcinoma is the most common malignant tumor in women, and it is the leading cause of mortality, with an incidence of >1,000,000 cases occurring worldwide annually. It is one of the most common human neoplasms, accounting for approximately one-quarter of all cancers in females worldwide and 27% of cancers in developed countries with a Western lifestyle. They exhibit a wide scope of morphological features, different immunohistochemical profiles, and unique histopathological subtypes that have specific clinical course and outcome. Breast cancers can be classified into distinct subgroups based on similarities in the gene expression profiles and molecular classification.