Discovery of novel mifepristone derivatives via suppressing KLF5 expression for the treatment of triple-negative breast cancer

Targeting key proteins involved in transcriptional regulation for cancer therapy: Current strategies and future prospective

The key proteins involved in transcriptional regulation play convergent roles in cellular homeostasis, and their dysfunction mediates aberrant gene expressions that underline the hallmarks of tumorigenesis. As tumor progression is dependent on such abnormal regulation of transcription, it is important to discover novel chemical entities as antitumor drugs that target key tumor-associated proteins involved in transcriptional regulation. Despite most key proteins (especially transcription factors) involved in transcriptional regulation are historically recognized as undruggable targets, multiple targeting approaches at diverse levels of transcriptional regulation, such as epigenetic intervention, inhibition of DNA-binding of transcriptional factors, and inhibition of the protein-protein interactions (PPIs), have been established in preclinically or clinically studies. In addition, several new approaches have recently been described, such as targeting proteasomal degradation and eliciting synthetic lethality. This review will emphasize on accentuating these developing therapeutic approaches and provide a thorough conspectus of the drug development to target key proteins involved in transcriptional regulation and their impact on future oncotherapy.

The roles and regulation of the KLF5 transcription factor in cancers

Krüppel‐like factor 5 (KLF5) is a member of the KLF family. Recent studies have suggested that KLF5 regulates the expression of a large number of new target genes and participates in diverse cellular functions, such as stemness, proliferation, apoptosis, autophagy, and migration. In response to multiple signaling pathways, various transcriptional modulation and posttranslational modifications affect the expression level and activity of KLF5. Several transgenic mouse models have revealed the physiological and pathological functions of KLF5 in different cancers. Studies of KLF5 will provide prognostic biomarkers, therapeutic targets, and potential drugs for cancers.

Synthesis and evaluation of novel thiosemicarbazone and semicarbazone analogs with both anti-proliferative and anti-metastatic activities against triple negative breast cancer

Triple-negative breast cancer (TNBC) is one of the most aggressive cancer with high mortality and recurrence rates. Hecogenin, a steroidal sapogenin, is reported as a potential anti-tumor agent against breast cancer. However, the moderate activity limits its further application in clinical. With the aim to identify novel analogues that are especially efficacious in therapy of TNBC, a series of novel hecogenin thiosemicarbazone and semicarbazone derivatives were designed, synthesized and biologically evaluated. Screening of cytotoxicity revealed that 4c could potently inhibit the proliferation of breast cancer cells (MCF-7 and MDA-MB-231 cells), lung cancer cells (A549) and colon cancer cells (HT-29) at low μM level. Importantly, further mechanism studies indicated the ability of 4c in inducing apoptosis of MDA-MB-231 cells by arresting the cell cycle. Moreover, 4c notably suppressed the migration and invasion of MDA-MB-231 cells compared to its parent hecogenin at the equal concentration.

Rational design and synthesis of 6-aryl-6H-benzo[c]chromenes as non-steroidal progesterone receptor antagonists for use against cancers

Progesterone receptor (PR) antagonists have been found to be effective for treating certain human cancers. However, the steroidal structure of PR antagonists could bind to other hormone receptors, thus leading to serious side effects. On the other hand, non-steroidal PR antagonists have rarely been evaluated for their anti-cancer efficacy. Therefore, identifying novel non-steroidal PR antagonists possessing potent anti-cancer efficacy would be an attractive project to pursue. In this study, we presented a new metal-free oxidative CH arylation method to rapidly synthesize a series of 6-aryl-6H-benzo[c]chromene derivatives. Multiple cancer cell lines were used for their anti-cancer activity screening. An extensive analysis of structure-activity relationships (SAR) of the derivatives revealed that compounds 32 and 34 markedly inhibited the proliferation of MCF-7 cells with IC₅₀ values of 6.32 ± 0.52 μM and 5.71 ± 0.49 μM, respectively. Further investigation indicated that derivatives 32 and 34 could elevate the expression of p21 and decrease the expressions of CDK4 and cyclin D1, leading to cell cycle arrest at G0/G1 phase. In addition, derivatives 32 and 34 could induce apoptosis of MCF-7 cells in both dose- and time-dependent manners by activation of p53 pathway, i.e., activation of Cleaved Caspase-3, p53 and P-p53 as well as elevation of the Bax/Bcl-2 ratio. Docking of derivatives 32 and 34 into a PR homology model exhibited potent PR antagonistic activity indicating the 6-aryl-6H-benzo[c]chromene derivatives are promising PR antagonists. We envisioned that derivatives 32 and 34 might be potential anti-cancer drug candidates as novel therapeutic treatment for breast cancer.

Effect of Down-Regulation of Long-Chain Non-Coding RNAs Myocardial Infarction Associated Transcript 2 Expression on Osteoarthritis Chondrocytes

Osteoarthritis (OA) is featured as articular cartilage degradation. LncRNA Mirt2 involves in inflammation, but its role in osteoarthritis is unclear. Our study intends to assess LncRNA Mirt2’s role in OA chondrocytes. The chondrocytes of OA patients (OA group) and healthy controls (control group) were isolated to measure LncRNA Mirt2 expression by Real time PCR. Chondrocytes were assigned into control group, LPS group, LPS + si-NC group, LPS + Mirt2 siRNA group followed by analysis of LncRNA Mirt2 level by real time PCR, cell proliferation by MTT assay, cell apoptosis by flow cytometry, expression of COL2A1, MMP13, ADAMTS-5, MEK1/2, Erk1/2 and phosphorylated Erk1/2 by western blot. LncRNA Mirt2 level was increased in OA chondrocytes. Under LPS stim-ulation, Mirt2 expression was significantly increased in chondrocytes and chondrocyte proliferation was decreased, along with significantly increased apoptosis and upregulated COL2A1, MMP13, ADAMTS-5, MEK1/2 and Erk1/2 and phosphorylated Erk1/2 (P < 0.05). Transfection of Mirt2 siRNA down-regulated its expression in chondrocytes stimulated by LPS, which significantly reversed the above changes (P < 0.05). LncRNA Mirt2 expression is increased in OA chondrocytes. Downregulation of LncRNA Mirt2 can regulate COL2A1, MMP13 and ADAMTS-5 level via MAPK/ERK signaling pathway, promote OA chondrocytes proliferation and inhibit apoptosis.

Potential Mechanisms of miR-143/Krupple Like Factor 5 Axis in Impeding the Proliferation of Michigan Cancer Foundation-7 Breast Cancer Cell Line

Breast cancer is one of the most prevailing cancers in females, while the cancerous heterogeneity hinders its early diagnosis and subsequent therapy. miR-143-3p is a critical mediator in malignancy development and tumorigenesis as a tumor suppressor. Its role in various tumor entities has been investigated, such as colon cancer and breast cancer. Using MCF-7 breast cancer cell model, we planned to explore the underlying mechanisms of miR-143/KLF-5 axis in retarding breast cancer cells growth. Bioinformatics analysis searched the target KLF5 of miR-143, and the miR-143-targeted mimic and inhibitor were employed to detect the changes of KLF5. After transfection of mimic miR-143, the CCK-8 reagent assessed cell proliferation. Based on optimal stimulation time, miR-143 stimulation model was established, followed by determining expression of KLF5, EGFR and PCNA via western blot and qPCR. Eventually, siRNA-KLF5 was applied to silencing KLF5 level to evaluate its role in MCF-7 cells. The transcription and translation levels of KLF5 were diminished in miR-143-mimic transfected MCF-7 cells, while enhanced in miR-143-inhibitor transfected MCF-7 cells. When MCF-7 cells were transfected with miR-143-mimic at different time points, 48 hours was found to be the optimal transfection time, with reduced transcription and translation levels of KLF5, EGFR and PCNA. The transcription and translation levels of PNCA and EGFR were declined after silencing KLF5 by siRNA. miR-143/KLF5 axis could retard the proliferation of MCF-7 breast cancer cells.

Krüppel-like factors in breast cancer: Function, regulation and clinical relevance

Breast cancer has accounted for the leading cause of cancer-related mortality among women worldwide. Although the progress in its diagnosis and treatment has come at a remarkable pace during the past several decades, there are still a wide array of problems regarding its progression, metastasis and treatment resistance that have not yet been fully clarified. Recently, an increasing number of studies have revealed that some members of Krüppel-like factors(KLFs) are significantly associated with cell proliferation, apoptosis, metastasis, cancer stem cell regulation and prognostic and predictive value for patients in breast cancer, indicating their promising prognostic and predictive potential for breast cancer survival and outcome. In this review, we will summarize our current knowledge of the functions, regulations and clinical relevance of KLFs in breast cancer.

Clinical Significance of Lysophosphatidic Acid Receptor-2 (LPA2) and Krüppel-Like Factor 5 (KLF5) Protein Expression Detected by Tissue Microarray in Gastric Adenocarcinoma

Background

The aim of this study was to evaluate lysophosphatidic acid receptor-2 (LPA2) and Krüppel-like factor 5 (KLF5) protein expression in gastric adenocarcinoma and their correlation with patient clinicopathological characteristics and prognosis.

Material/Methods

Fifty-one gastric adenocarcinoma tissue samples, 21 gastric intraepithelial neoplasia (GIN) samples, and 13 normal gastric tissue samples were collected to test for LPA2 and KLF5 expression by tissue microarray and immunohistochemistry assay. LPA2 and KLF5 positive expression rate between gastric adenocarcinoma, GIN, and normal gastric tissue were compared. The relationship between LPA2 expression, KLF5 expression, and patients’ clinicopathological characteristics and prognosis were evaluated.

Results

The positive expression rate of LPA2 and KLF5 were statistical different in gastric adenocarcinoma, GIN, and normal gastric tissue (P<0.05). LPA2 positive expression was associated with tumor invasion depth, Lauren type, vascular invasion, local lymph node metastasis, and clinical stage (P<0.05). There was no correlation between LPA2 expression (hazard ratio [HR]=1.84, 95% confidence interval [CI]: 0.89–3.80, P>0.05), KLF5 expression (HR=1.13, 95% CI: 0.53–2.36, P>0.05), and gastric cancer patients’ overall survival.

Conclusions

LPA2 and KLF5 protein expressions were differently expressed in gastric adenocarcinoma, GIN, and normal gastric tissue, and differences were correlated with patients’ clinical characteristic. However, LPA2 and KLF5 expressions were not correlated with the patients’ prognosis.

Biomimetic Oxidative Coupling Cyclization Enabling Rapid Construction of Isochromanoindolenines

Herein, we report a biomimetic oxidative coupling cyclization strategy for the highly efficient functionalization of tetrahydrocarbolines (THCs). This process enables rapid access to complex isochromanoindolenine scaffolds in moderate to excellent yields. The reaction proceeds smoothly and rapidly (complete within minutes) in an open flask. This operationally simple protocol is scalable and compatible with a wide range of functional groups. Late-stage functionalization of a pharmacologically relevant molecule is also demonstrated.