Identification of BMI1 promoter inhibitors from Streptomyces sp. IFM-11958

Metabolites from Streptomyces aureus (VTCC43181) and Their Inhibition of Mycobacterium tuberculosis ClpC1 Protein

Tuberculosis is one of the most common infectious diseases in the world, caused by Mycobacterium tuberculosis. The outbreak of multiple drug-resistant tuberculosis has become a major challenge to prevent this disease worldwide. ClpC1 is a Clp ATPase protein of Mycobacterium tuberculosis, functioning as a chaperon when combined with the Clp complex. ClpC1 has emerged as a new target to discover anti-tuberculosis drugs. This study aimed to explore the ClpC1 inhibitors from actinomycetes, which have been known to provide abundant sources of antibiotics. Two cyclic peptides, including nocardamin (1), halolitoralin A (3), and a lactone pleurone (2), were isolated from the culture of Streptomyces aureus (VTCC43181). The structures of these compounds were determined based on the detailed analysis of their spectral data and comparison with references. This is the first time these compounds have been isolated from S. aureus. Compounds 1-3 were evaluated for their affection of ATPase activity of the recombinant ClpC1 protein. Of these compounds, halolitoralin A (1), a macrocyclic peptide, was effective for the ATPase hydrolysis of the ClpC1 protein.

Critical Roles of Polycomb Repressive Complexes in Transcription and Cancer

Polycomp group (PcG) proteins are members of highly conserved multiprotein complexes, recognized as gene transcriptional repressors during development and shown to play a role in various physiological and pathological processes. PcG proteins consist of two Polycomb repressive complexes (PRCs) with different enzymatic activities: Polycomb repressive complexes 1 (PRC1), a ubiquitin ligase, and Polycomb repressive complexes 2 (PRC2), a histone methyltransferase. Traditionally, PRCs have been described to be associated with transcriptional repression of homeotic genes, as well as gene transcription activating effects. Particularly in cancer, PRCs have been found to misregulate gene expression, not only depending on the function of the whole PRCs, but also through their separate subunits. In this review, we focused especially on the recent findings in the transcriptional regulation of PRCs, the oncogenic and tumor-suppressive roles of PcG proteins, and the research progress of inhibitors targeting PRCs.

Natural Compounds with BMI1 Promoter Inhibitory Activity from Mammea siamensis and Andrographis paniculata

A new coumarin derivative (1) and 30 known compounds were isolated from Mammea siamensis and Andrographis paniculata, guided by B cell-specific Moloney murine leukemia virus insertion region 1 (BMI1) promoter inhibitory activity. Among the isolated compounds, 15 compounds showed BMI1 promoter inhibitory activity, and five compounds were found to be cytotoxic. 14-Deoxy-11,12-dehydroandrographolide (18) was highly cytotoxic to DU145 cells with an IC50 value of 25.4 µM. Western blotting analysis of compound 18 in DU145 cells suggested that compound 18 suppresses BMI1 expression.

Screening study of cancer-related cellular signals from microbial natural products

To identify bioactive natural products from various natural resources, such as plants and microorganisms, we investigated programs to screen for compounds that affect several cancer-related cellular signaling pathways, such as BMI1, TRAIL, and Wnt. This review summarizes the results of our recent studies, particularly those involving natural products isolated from microbial resources, such as actinomycetes, obtained from soil samples collected primarily around Chiba, Japan.

Comparative evaluation of BMI-1 proto-oncogene expression in normal tissue, adenoma and papillary carcinoma of human thyroid in pathology samples

Objective

Papillary Thyroid carcinoma accounts for more than 60% of adult thyroid carcinomas. Finding a helpful marker is vital to determine the correct treatment approach. The present study was aimed to evaluate the expression of the B cell-specific Moloney murine leukemia virus integration site 1 (BMI-1) gene in papillary carcinoma, adenoma, and adjacent healthy thyroid tissues. Pathology blocks of thyroid tissues at the pathology department of patients who have undergone thyroid surgery between 2015 and 2019 were examined; papillary carcinoma, adenoma, and healthy tissues were selected and sectioned. Total RNA was extracted, and the relative expression level of the BMI-1 gene was examined using the Real-Time qPCR method.

Results

In the papillary and adenoma tissues, BMI-1 was overexpressed (1.047-fold and 1.042-fold) in comparison to healthy tissues (p < 0.05 for both comparisons). However, no statistically significant differences were observed between adenoma and papillary carcinoma tissues regarding BMI-1 gene expression. This study demonstrated a new biomarker for thyroid malignancies and found that the mRNA levels of the BMI-1 gene were higher in tumor tissues compared with healthy tissues. Further studies are needed to evaluate the BMI1 gene expression in other thyroid cancers.

Nonactic Acid Derivatives Isolated From Streptomyces werraensis IFM12104 in a Screening Program for BMI1 Promoter Inhibitory Activity

Upon screening for compounds with B cell-specific Moloney murine leukemia virus region 1 (BMI1) promoter inhibitory activity, 3 nonactic acid derivatives (1-3) were isolated from Streptomyces werraensis IFM12104. Although spectral data of compound 1 were identical with those reported in literature for 4α-(3, 5-dihydroxy-heptyl)-3α-methyl-2-oxetanone (4), compound 1 was revealed to be homononactic acid by X-ray analysis. Compounds 2 and 3 were identified as bishomononactic acid and nonactic acid using spectral data. The 3 compounds 1 to 3 inhibited BMI1 promoter activities with IC50 values of 240, 160, and 180 μM, respectively.