A modified natural small molecule inhibits triple-negative breast cancer growth by interacting with Tubb3.

BACKGROUND: Triple-negative breast cancer (TNBC) is a malignant tumor without specific therapeutic targets and a poor prognosis. Chemotherapy is currently the first-line therapeutic option for TNBC. However, due to the heterogeneity of TNBC, not all of TNBC patients are responsive to chemotherapeutic agents. Therefore, the demand for new targeted agents is critical. ß-tubulin isotype III (Tubb3) is a prognostic factor associated with cancer progression, including breast cancer, and targeting Tubb3 may lead to improve TNBC disease control. Shikonin, the active compound in the roots of Lithospermun erythrorhizon suppresses the growth of various types of tumors, and its efficacy can be improved by altering its chemical structure. PURPOSE: In this work, the anti-TNBC effect of a shikonin derivative (PMMB276) was investigated, and its mechanism was also investigated. STUDY DESIGN/METHODS: This study combines flow cytometry, immunofluorescence staining, immunoblotting, immunoprecipitation, siRNA silencing, and the iTRAQ proteomics assay to analyze the inhibition potential of PMMB276 on TNBC. In vivo study was performed, Balb/c female murine models with or without the small molecule treatments. RESULTS: Herein, we screened 300 in-house synthesized analogs of shikonin against TNBC and identified a novel small molecule, PMMB276; it suppressed cell proliferation, induced apoptosis, and arrested the cell cycle at the G2/M phase, suggesting that it could have a tumor suppressive role in TNBC. Tubb3 was identified as the target of PMMB276 using proteomic and biological activity analyses. Meanwhile, PMMB276 regulated microtubule dynamics in vitro by inducing microtubule depolymerization and it could act as a tubulin stabilizer by a different process than that of paclitaxel. Moreover, suppressing or inhibiting Tubb3 with PMMB276 reduced the growth of breast cancer in an experimental mouse model, indicating that Tubb3 plays a significant role in TNBC progression. CONCLUSION: The findings support the therapeutic potential of PMMB276, a Tubb3 inhibitor, as a treatment for TNBC. Our findings might serve as a foundation for the utilization of shikonin and its derivatives in the development of anti-TNBC.

Excess copper promotes catabolic activity of gram-positive bacteria and resistance of gram-negative bacteria but inhibits fungal community in soil.

The extensive use of copper fungicides has resulted in significant non-target effects on soil microbial communities. However, the documented effects are often variable and contradictory, depending on the methods used to assess them. In this study, we examined the effects of copper accumulation in surface soils on microbial catabolic activity, active biomass and composition, and sensitive bacterial species. The community-level catabolic profiles (CLCPs) showed that both normal (50 mg CuSO4 kg-1 soil) and high dosages (tenfold rate) of CuSO4 significantly increased the catabolic diversity of gram-positive bacteria, while the high dosage increased the overall catabolic activity of gram-negative bacteria. The phospholipid fatty acid (PLFA) analysis showed that the high dosage reduced the biomass of gram-positive bacteria by 27% but did not affect that of gram-negative bacteria. In comparison, the normal and high dosages decreased the fungal biomass by 34% and 58%, respectively. Furthermore, 16S rRNA-denaturing gradient gel electrophoresis (DGGE) fingerprint revealed that more than two-thirds of identified bands belonged to gram-negative bacteria. Some Cu-resistant gram-negative bacterial genera, such as Actinobacterium, Pseudomonas, and Proteobacterium, were detected in the soil to which the high dosage of CuSO4 had been applied. In conclusion, an excess application of CuSO4 increased the catabolic diversity of gram-positive bacteria and induced resistance in gram-negative bacteria, whereas the active fungal community displayed a dosage-dependent response to CuSO4 and can thus be used as a sensitive indicator of copper contamination.

Progress on biosynthesis and function of the natural products of Zi Cao as a traditional Chinese medicinal herb.

Zi Cao is an important traditional medicinal plant resource in China. Shikonin and its derivatives, as the purple-red naphthoquinones among natural products of its roots, are commonly used clinically in the treatment of sores and skin inflammations. Over the past few decades, due to their highly effective multiple biological activities, pharmacological effects, good clinical efficacy and high utilization value, shikonin and its derivatives have attracted increasing attention of domestic and foreign researchers. For this reason, the wild plant germplasm resources have been suffering a grievous exploitation, leading to a serious threat to the habitat. With the development of the biosynthesis, molecular metabolism and biotechnology, as well as the continuous innovation of research methods on the biological activities and pharmacological effects of plant natural products, significant progress has been made in the research on the biosynthetic pathways and related regulatory genes of shikonin. The pharmacological action and its mechanism of shikonin have also been deeply elucidated, which greatly promoted the basic research and clinical application development of shikonin. In this review, we briefly introduce and analyze the classification of Zi Cao, structure and composition of natural shikonin and its biosynthesis pathway, functional genes related to the regulation of shikonin biosynthesis, and biological activities and pharmacological functions of shikonin. Finally, we address possible prospective for the trend on the future research and development of natural shikonin and its derivatives, hoping to provide a useful reference for the deep mining and development of medicinal natural products from important Chinese medicinal materials, and to promote the modern development of traditional Chinese medicine.

Differential microbial assemblages associated with shikonin-producing Borage species in two distinct soil types.

Shikonin and its derivatives are the main components of traditional Chinese medicine, Zicao. The pharmacological potential of shikonin and its derivatives have been extensively studied. Yet, less is known about the microbial assemblages associated with shikonin producing Borage plants. We studied microbial profiles of two Borage species, Echium plantagineum (EP) and Lithospermum erythrorhizon (LE), to identify the dynamics of microbial colonization pattern within three rhizo-compatments and two distinct soil types. Results of α and ß-diversity via PacBio sequencing revealed significantly higher microbial richness and diversity in the natural soil along with a decreasing microbial gradient across rhizosphere to endosphere. Our results displayed genotype and soil type-dependent fine-tuning of microbial profiles. The host plant was found to exert effects on the physical and chemical properties of soil, resulting in reproducibly different micro-biota. Analysis of differentially abundant microbial OTUs displayed Planctomycetes and Bacteroidetes to be specifically enriched in EP and LE rhizosphere while endosphere was mostly prevailed by Cyanobacteria. Network analysis to unfold co-existing microbial species displayed different types of positive and negative interactions within different communities. The data provided here will help to identify microbes associated with different rhizo-compartments of potential host plants. In the future, this might be helpful for manipulating the keystone microbes for ecosystem functioning.

Glyphosate application increased catabolic activity of gram-negative bacteria but impaired soil fungal community.

Glyphosate is a non-selective organophosphate herbicide that is widely used in agriculture, but its effects on soil microbial communities are highly variable and often contradictory, especially for high dose applications. We applied glyphosate at two rates: the recommended rate of 50 mg active ingredient kg-1 soil and 10-fold this rate to simulate multiple glyphosate applications during a growing season. After 6 months, we investigated the effects on the composition of soil microbial community, the catabolic activity and the genetic diversity of the bacterial community using phospholipid fatty acids (PLFAs), community level catabolic profiles (CLCPs), and 16S rRNA denaturing gradient gel electrophoresis (DGGE). Microbial biomass carbon (Cmic) was reduced by 45%, and the numbers of the cultivable bacteria and fungi were decreased by 84 and 63%, respectively, under the higher glyphosate application rate. According to the PLFA analysis, the fungal biomass was reduced by 29% under both application rates. However, the CLCPs showed that the catabolic activity of the gram-negative (G-) bacterial community was significantly increased under the high glyphosate application rate. Furthermore, the DGGE analysis indicated that the bacterial community in the soil that had received the high glyphosate application rate was dominated by G- bacteria. Real-time PCR results suggested that copies of the glyphosate tolerance gene (EPSPS) increased significantly in the treatment with the high glyphosate application rate. Our results indicated that fungi were impaired through glyphosate while G- bacteria played an important role in the tolerance of microbiota to glyphosate applications.

The evaluation of potent antitumor activities of shikonin coumarin-carboxylic acid, PMMB232 through HIF-1α-mediated apoptosis.

In current study, a series of shikonin derivatives were synthesized and its anticancer activity was evaluated. As a result, PMMB232 showed the best antiproliferation activity with an IC50 value of 3.25±0.35µM. Further, treatment of HeLa cells with a variety of concentrations of target drug resulted in dose-dependent event marked by apoptosis. What's more, the mitochondrial potential (Δym) analysis was consistent with the apoptosis result. In addition, PARP was involved in the progress of apoptosis revealed by western blotting. To identify the detailed role and mechanism of PMMB232 in the progression of human cervical cancer, we detected the expression of HIF-1α and E-cadherin in HeLa cells. Results showed that expression of HIF-1α was downregulated, while E-cadherin protein was upregulated. Meanwhile, glycolysis related protein PDK1 was decreased in HeLa cells. Conversely, the expression of PDH-E1α was upregulated. Docking simulation results further indicate that PMMB232 could be well bound to HIF-1α. Taken together, our data indicate that compound PMMB232 could be developed as a potential anticancer agent.

[Nucleotide polymorphism and molecular evolution of the LRR region in potato late blight resistance gene Rpi-blb2].

Rpi-blb2, which is originally derived from Solanum bulbocastanum, is a broad-spectrum potato late blight resistance gene and belongs to the NBS-LRR family. Here, the LRR homologues of Rpi-blb2 were cloned with PCR method from 40 potato cultivars (including 20 resistant potato cultivars and 20 susceptible ones) and 7 wild potato populations. Then, the similarities of the sequences, polymorphic (segregating) sites, and nucleotide diversities were estimated by bioinformatic methods. The results showed that high nucleotide polymorphism and some hot-spot mutations existed in the LRR region of Rpi-blb2. The test of Ka/Ks ratio showed that the function of LRR was conserved because of the purifying selection, although different positions of the Rpi-blb2 LRR region were under different selection pressures. Moreover, the LRR region of Rpi-blb2 had no clear differentiation between the cultivated and wild potatoes.