Using gene expression data to direct breast cancer therapy: evidence from a preclinical trial

Personalized oncology and BRAFK601N melanoma: model development, drug discovery, and clinical correlation

PURPOSE

Mutations in BRAF are the most prominent activating mutations in melanoma and are increasingly recognized in other cancers. There is currently no accepted treatment regimen for patients with mutant BRAF^K601N melanoma, and the study of melanoma driven by BRAF mutations at the 601 locus is lacking due to a paucity of cellular model systems. Therefore, we sought to better understand the treatment and clinical approach to patients with mutant BRAF^K601N melanoma and subsequently develop a novel personalized oncology platform for rare or treatment-refractory cancers.

METHODS

We developed and characterized the first patient-derived, naturally occurring BRAF^K601N melanoma model, described herein as OHRI-MEL-13, and assessed efficacy using the Prestwick Chemical Library and select targeted therapeutics.

RESULTS

OHRI-MEL-13 exhibits loss of heterozygosity of BRAF, closely mimics the original tumor's gene expression profile, is tumorigenic in immune-deficient murine models, and is available for public accession through American Type Culture Collection. We present in silico modeling data, which illustrates the therapeutic failure of BRAF^V600E-targeted therapies in BRAF^K601N mutants. Our platform elucidated a unique role for MEK inhibition with cobimetinib, which resulted in short-term clinical success by reducing the metastatic burden.

CONCLUSION

Our model of BRAF^K601N-activated melanoma was developed, thoroughly characterized, and made available for public accession. This model served to demonstrate the feasibility of a novel personalized oncology platform that could be optimized at an institutional level for rare variant or treatment-refractory cancers. We also demonstrate the clinical utility of monotherapy MEK inhibition in a case of BRAF^K601N melanoma.

Current advances in the diagnosis and personalized treatment of breast cancer: lessons from tumor biology

Breast cancer treatment has advanced enormously in the last decade. Most of this is due to advances reached in the knowledge regarding tumor biology, mainly in the field of diagnosis and treatment. This review brings information about how the genomics-based information contributed to advances in breast cancer diagnosis and prognosis perspective, as well as presents how tumor biology discoveries fostered the main therapeutic approaches available to treat such patients, based on a personalized point of view.

Tumor targeting antibody-conjugated nanocarrier with pH/thermo dual-responsive macromolecular film layer for enhanced cancer chemotherapy

In response to changeful tumor environment, self-targeting antibody-mediated drug nanocarrier with functionalization have been broadly developed to realize specific antitumor efficacy. In this work, an antibody-conjugated drug delivery system with pH/temperature dual-responsive property was devised and fabricated based on mesoporous silica nanoparticle (MSN). Briefly, MSN was first modified with the pH/temperature dual-responsive macromolecular copolymer P(NIPAm-co-MAA) via a precipitation polymerization method, and then grafted with the anti-human epidermal growth factor receptor 2 (HER2) single chain antibody fragment (scFv) to specifically target HER2 positive breast cancer cells. With this structure, such targeting nanoparticles eventually exhibited high drug loading capacity and good biocompatibility. Meanwhile, the cumulative in vitro drug release profile displayed a low-level early leakage at neutral pH values/low temperature while remarkably enhanced release at an acidic pH value/high temperature, indicating an apparent pH/temperature-triggered drug release pattern. Moreover, tumor-targeting assay revealed that the anti-HER2 scFv-surface decoration greatly enhanced the cellular uptake of as-prepared nanoparticle through HER2-antibody-mediated endocytosis, as well as improved the uptake selectivity between normal and cancer cells. More importantly, both the in vitro and in vivo anticancer experiments indicated that such targeting dual-responsive nanoplatform could efficiently inhibit the growth of HER2 positive breast cancer with minimal side effects. Collectively, all these results promised such specific-targeted and dual-responsive nanoparticle a smart drug delivery system, and it provided a promising perspective in efficient and controllable cancer therapeutic application.

Deletion of HNF1A-AS1 Suppresses the Malignant Phenotypes of Breast Cancer Cells In Vitro and In Vivo Through Targeting miRNA-20a-5p/TRIM32 Axis

Background: Hepatocyte nuclear factor 1 homeobox A-antisense RNA 1 (HNF1A-AS1) is a long noncoding RNA and controls human tumor development and progression. However, its expression and role in breast cancer, the most overwhelmingly occurring malignancy in women globally, remain poorly illuminated. Materials and Methods: Expression of HNF1A-AS1, miRNA (miR)-20a-5p, and tripartite motif containing 32 (TRIM32) was detected using quantitative real-time polymerase chain reaction and Western blotting. Cell proliferation, apoptosis, migration, and invasion were measured by cellTiter 96 AQueous one solution cell proliferation assay kit, flow cytometry, and transwell assays, respectively. Epithelial-mesenchymal transition (EMT) was evaluated by Western blotting, analyzing E-cadherin, N-cadherin, and vimentin expression. Mice xenograft model was generated to investigate tumor growth in vivo. The target binding among miR-20a-5p, HNF1A-AS1, and TRIM32 was confirmed by dual-luciferase reporter assay. Results: Expression of HNF1A-AS1 and TRIM32 was upregulated and miR-20a-5p was downregulated in breast cancer tumors and cell lines. Deletion of HNF1A-AS1 induced cell apoptosis rate, but suppressed cell proliferation, EMT, migration, and invasion in MDA-MB-231 and MCF-7 cells. Furthermore, HNF1A-AS1 downregulation impeded tumor growth in vivo. Interestingly, miR-20a-5p overexpression elicited the similar suppressive effects in MDA-MB-231 and MCF-7 cells, which was partially reversed by TRIM32 upregulation; besides, miR-20a-5p silencing could abolish the antitumor role of HNF1A-AS1 deletion. Notably, HNF1A-AS1 positively modulated TRIM32 expression through acting as a molecular "sponge" for miR-20a-5p. Conclusions: Knockdown of HNF1A-AS1 suppressed breast carcinogenesis presumably through targeting miR-20a-5p/TRIM32 axis, suggesting that HNF1A-AS1 might be a promising therapy target for breast cancer.

Identification of FOXM1 as a specific marker for triple‑negative breast cancer

The present study aimed to identify the therapeutic role of the forkhead box M1 (FOXM1)-associated pathway in triple-negative breast cancer (TNBC). Using a Cancer Landscapes-based analysis, a gene regulatory network model was constructed. The present results demonstrated that FOXM1 occupies a key position in gene networks and is a critical regulatory gene in breast cancer. Using breast carcinoma gene expression data from The Cancer Genome Atlas, it was identified that FOXM1 expression was increased in the basal-like breast cancer subtype compared with other breast cancer subtypes. RNA-sequencing analysis of MDA-MB-231 cells treated with 4 and 10 µl/ml Thiostrepton identified 662 and 5,888 significantly differentially expressed genes, respectively. The Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses demonstrated that FOXM1 was highly associated with multiple biological processes and was markedly associated with metabolic pathways in TNBC. The use of Search Tool for the Retrieval of Interacting Genes/Proteins provided a critical assessment and integration of protein-protein interactions, and demonstrated the multiple important functions of FOXM1 in TNBC. Real-time cell analysis, reverse transcription-quantitative polymerase chain reaction and immunofluorescence staining were used to assess the anti-tumor activity of Thiostrepton in TNBC cells in vitro. The present results identified that suppression of FOXM1 using Thiostrepton inhibited MDA-MB-231 cell proliferation and the expression of cell cycle-associated genes, including cyclin A2, cyclin B2, checkpoint kinase 1, centrosomal protein 55 and polo like kinase 1. Immunofluorescence staining analysis demonstrated that vimentin, filamentous actin and zinc finger E-box-binding homeobox 1 were all decreased following treatment with Thiostrepton. Furthermore, a BALB/C nude mouse subcutaneous xenograft model was used to verify the function of FOXM1 in vivo. The present results demonstrated that FOXM1 inhibition significantly suppressed MDA-MB-231 cell tumorigenesis in vivo. Overall, the present results suggested that FOXM1 is a key gene that serves important roles in multiple biological processes in TNBC and that it may serve as a novel therapeutic target in TNBC.

Knockdown of ZEB1 suppressed the formation of vasculogenic mimicry and epithelial-mesenchymal transition in the human breast cancer cell line MDA-MB-231

Breast cancer is a common malignant tumor in women. It has been suggested that a type of microcirculation pattern that does not rely on host microvascular endothelial cells known as vasculogenic mimicry (VM) may contribute to the poor effect of anti‑angiogenesis treatment on some patients with breast cancer. However, the formation and regulatory mechanism of VM in breast cancer are unclear and still require further investigation. The present study examined whether decreasing the expression of zinc finger E‑box binding homeobox (ZEB1) using siRNA can inhibit the formation of VM in Triple Negative Breast Cancer (TNBC), and its specific function and molecular mechanism. mRNA and protein expression were detected by RT‑qPCR and western blotting. Invasion assay and tube formation assay were also performed. The results demonstrated that ZEB1 small hairpin (sh)RNA inhibited the formation of VM. Knockdown of ZEB1 markedly inhibited the expression of vimentin in MDA‑MB‑231 cells and markedly increased the expression of E‑cadherin. It was suggested that ZEB1 shRNA may have inhibited the epithelial‑mesenchymal transition (EMT). In addition, ZEB1 shRNA inhibited the invasion of MDA‑MB‑231 cells and suppressed the expression of fetal liver kinase 1 (flk‑1). The flk‑1 inhibitor Semaxanib inhibited the formation of VM; thus, ZEB1 shRNA inhibited EMT and cell invasion, and may have inhibited the formation of VM through flk‑1. The present study contributed further understanding on the theory of tumor angiogenesis and provided theoretical basis for novel targeted therapy of TNBC.