Glutathione depletion and dihydroorotate dehydrogenase inhibition actuated ferroptosis-augment to surmount triple-negative breast cancer.

Ferroptosis is a promising therapeutic approach for combating malignant cancers, but its effectiveness is limited in clinical due to the adaptability and self-repair abilities of cancer cells. Mitochondria, as the pivotal player in ferroptosis, exhibit tremendous therapeutic potential by targeting the intramitochondrial anti-ferroptotic pathway mediated by dihydroorotate dehydrogenase (DHODH). In this study, an albumin-based nanomedicine was developed to induce augmented ferroptosis in triple-negative breast cancer (TNBC) by depleting glutathione (GSH) and inhibiting DHODH activity. The nanomedicine (ATO/SRF@BSA) was developed by loading sorafenib (SRF) and atovaquone (ATO) into bovine serum albumin (BSA). SRF is an FDA-approved ferroptosis inducer and ATO is the only drug used in clinical that targets mitochondria. By combining the effects of SRF and ATO, ATO/SRF@BSA promoted the accumulation of lipid peroxides within mitochondria by inhibiting the glutathione peroxidase 4 (GPX4)-GSH pathway and downregulating the DHODH-coenzyme Q (CoQH2) defense mechanism, triggers a burst of lipid peroxides. Simultaneously, ATO/SRF@BSA suppressed cancer cell self-repair and enhanced cell death by inhibiting the synthesis of adenosine triphosphate (ATP) and pyrimidine nucleotides. Furthermore, the anti-cancer results showed that ATO/SRF@BSA exhibited tumor-specific killing efficacy, significantly improved the tumor hypoxic microenvironment, and lessened the toxic side effects of SRF. This work presents an efficient and easily achievable strategy for TNBC treatment, which may hold promise for clinical applications.

Onset and Recurrence Characteristics of Chinese Patients with Noncardiogenic Ischemic Stroke in Chinese Medicine Hospital.

OBJECTIVE: To delineate the onset and recurrence characteristics of noncardiogenic ischemic stroke patients in China. METHODS: A prospective, multicenter and registry study was carried out in 2,558 patients at 7 representative clinical sub-centers during November 3, 2016 to February 17, 2019. A questionnaire was used to collect information of patients regarding CM syndromes and constitutions and associated risk factors. Additionally, stroke recurrence was defined as a primary outcome indicator. RESULTS: A total of 327 (12.78 %) patients endured recurrence events, 1,681 (65.72%) were men, and the average age was 63.33 ± 9.45 years. Totally 1,741 (68.06%) patients suffered first-ever ischemic stroke, 1,772 (69.27%) patients reported to have hypertension, and 1,640 (64.11%) of them reported dyslipidemia, 1,595 (62.35%) patients exhibited small-artery occlusion by The Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification. Specifically, 1,271 (49.69%) patients were considered as qi-deficient constitution, and 1,227 (47.97%) patients were determined as stagnant blood constitution. There were 1,303 (50.94%) patients diagnosed as blood stasis syndrome, 1,280 (50.04%) patients exhibited phlegm and dampness syndrome and 1,012 (39.56%) patients demonstrated qi deficiency syndrome. And 1,033 (40.38%) patients declared intracranial artery stenosis, and 478 (18.69%) patients reported carotid artery stenosis. The plaque in 1,508 (41.36%) patients were of mixed. Particularly, 41.09% of them demonstrated abnormal levels of glycated hemoglobin levels. CONCLUSIONS: Recurrence in minor and small-artery stroke cannot be ignored. Hypertension, dyslipidemia, abnormal HbA1c, intracranial artery stenosis and carotid plaque were more common in stroke patients. Particularly, phlegm-dampness and blood stasis syndromes, as well as qi deficiency and blood stasis constitutions, were still the main manifestations of stroke. (Trial registration at ClinicalTrials.gov No. NCT03174535).

[Experts consensus statement on Qilong Capsules in clinical practice].

Qilong Capsules is the representative Chinese patent medicine of the theory of " invigorating Qi and activating blood circulation" in traditional Chinese medicine( TCM),with distinct characteristics of TCM in clinical application. Qilong Capsules indication on package insert is ischemic stroke( cerebral infarction),which is a complex disease and has many pathological links. The treatment principles and methods at various stages are different. Inappropriate time of intervention,dosage and course of treatment make it difficult to give full play to the efficacy,but also cause adverse reactions,such as bleeding. In order to promote the rational use of Qilong Capsules,the project team invited frontline clinical experts,pharmaceutical experts and methodologist of evidence-based medicine around China to develop the consensus. The consensus is based on a combination of clinical research evidence and expert experi-ence to give recommendations for clinical problems with evidence support and expert consensus suggestions for clinical problems without evidence support. The consensus recommends the indication,timing of intervention,dosage,course of treatment,combined medication and contraindications of Qilong Capsules in clinical application,and introduced its safety characteristics,in order to guide clinical medical workers( involving Chinese medicine,Western medicine,combining traditional Chinese and Western medicine) to use Qilong Capsules reasonably in the treatment of cerebral infarction.

[Research progress on anti-cancer mechanisms of arsenic trioxide and artemisinin].

The formation and metastasis of tumor cells are closely related to the gene regulation. It is critical to elucidate the molecular mechanism of a compound using in cancer therapy. In this article, we reviewed the anti-cancer molecular mechanism of arsenic trioxide and artemisinin. Its anti-cancer function mainly includes: regulation of cell cycle regulatory proteins to inhibit tumor cell proliferation, cell apoptosis signal transduction pathway to promote apoptosis in tumor cells, immortalization associated genes to reduce the life of tumor cells, angiogenesis/invasion/metastasis gene to block the spread of tumor cells, promoter methylation and protein ubiquitination gene to enhance anti-oncogene expression and ubiquitin- mediated protein degradation, micro RNA to inhibit proliferation or induce apoptosis in tumor cells, DNA synthesis and repair of DNA damage and repair gene to decrease the DNA synthesis of tumor cells, signal transduction pathways of cell proliferation/apoptosis and invasion/metastasis etc., the expression of hormone receptors and so on. We indicated the problems existing in current studies and also prospected the future of using the compound to fight cancer.

Monomorphic RNA G-quadruplex and polymorphic DNA G-quadruplex structures responding to cellular environmental factors.

We systematically and quantitatively investigated the structure and thermodynamics of G-quadruplexes of RNAs and corresponding DNAs of the same sequences under molecular crowding conditions that mimic the high osmotic stress induced by the numerous molecules inside of living cells. Structural analyses demonstrated that various telomere RNA sequences folded into parallel-stranded G-quadruplexes in a manner independent of the surrounding conditions with different cations under both dilute and molecular crowding conditions. In contrast, DNA G-quadruplexes showed structural polymorphism. Moreover, we demonstrated that the G-quadruplexes of the RNA sequences were more stable than those of the same DNA sequences. These results show that a single and robust RNA G-quadruplex structure can exist in a manner independent of the sequence and surrounding conditions. To confirm this, we studied a guanine-rich sequence located in the 5'-untranslated region of human bcl-2 mRNA that is thought to play a role in translation. The results revealed a stable parallel G-quadruplex that formed under all conditions tested. For example, a bcl-RNA G-quadruplex in the presence of 5 mM KCl [free energy change at 25 degrees C (DeltaG degrees (25)) of -5.42 kcal/mol] was more stable than its corresponding DNA G-quadruplex (DeltaG degrees (25) = -2.31 kcal/mol). Our results further indicated that water molecules binding to the 2'-OH group of RNA G-quadruplexes play a critical role in their formation and stability.

[Notch signaling in human breast cancer].

OBJECTIVE: To explore the role of Notch signaling in human breast cancers, the expression of Notch1 and its ligand JAG1 in human breast cancers and their relationships with clinical stages of breast cancers were analyzed. METHODS: RT-PCR was used to detect the expression of Notch1 and JAG1 in 62 breast cancer specimens and 22 normal breast tissues at the margin of tumor sections, and the statistical difference of expression rates and standardized coefficient between the two groups were analyzed. To compare the expression intensity of Notch1 and JAG1 at different development stages of the illness and at different stages with or without axillary node metastasis. RESULTS: The expression rate and standardized coefficient of Notch1 in human breast cancers were significantly higher than those of normal breast tissues at the margin of tumor sections. The expression rate of JAG1 in human breast cancers was 15%, while JAG1 was not detected in normal breast tissues at the margin of tumor sections. The standardized coefficient of Notch1 in cases with axillary node metastasis was significantly higher than that in cases without axillary node metastasis. The standardized coefficient of Notch1 at stage I was significantly lower than that at stage II, and stage II was significantly higher than stage III. There was no statistically significant difference between stage I and stage III. CONCLUSION: Notch1 and JAG1 are highly expressed in human breast cancers, indicating that the aberrant expression and activation of Notch1 may be related with tumorigenesis of human breast cancer. Notch1 may play different roles at different developmentl stages of human breast cancer.

[Reversal of multi-drug resistance in K562/A02 cells by two short hairpin RNAs (shRNA) of mdr1].

OBJECTIVE: To construct two recombinant plasmids of mdr1 and mcl1 shRNA, and to investigate their reversal effect on drug resistance in K562 adriamycin resistant cell lines (K562/A02). METHODS: Two oligonucleotides of mdr1 and mcl1 gene were designed referring to that of GenBank, double-stranded DNA was derived through annealing, and cloned into pRNAT vector digested by two restricted endoenzymes. K562/A02 cells were transfected with the recombinant plasmids. The mdr1 mRNA expression and its protein product P-glycoprotein (P-gp) were detected by RT-PCR and flow cytometry. The expression of mcl1 gene was detected by RT-PCR. 50% inhibition concentration (IC50) of adriamycin (ADM) on K562/A02 cells was determined by MTT method. Cells apoptosis was analyzed by flow cytometry. RESULTS: Comparing with K562/A02 cells, the shRNA of mdrl or mcl1 gene in vitro can remarkably increase the sensitivity of K562/A02 to adriamycin, down-regulate mdr1 or mcl1 gene expression, increase the K562/A02 cells apoptosis rates induced by adriamycin. Cotransfection of mdrl and mcl1 genes shRNA can also down-regulate the expression of their gene, more remarkably increase the sensitivity and apoptosis of K562/ A02 to adriamycin. CONCLUSION: Transfection of mdrl or mcl1 gene shRNA can promote the sensitivity of K562/A02 to adriamycin and cotransfection of the two shRNA can more remarkably do so. The mel1 gene might be involved in adriamycin resistant in K562/A02 cells.

Properties of long human telomeric DNAs under cell-mimicking conditions.

We investigated the stability and structure of long telomeric DNAs derived from human, (TTAGGG)(n) (n=4-12) in the presence of 100 mM K(+) at 0 wt% or 20 wt% poly(ethylene glycol) 200 (PEG200) utilizing circular dichroism and UV melting analysis. The results showed that the values of enthalpy and entropy changes for the G-quadruplex formation of the telomeric DNAs whose repeat number was multiple of four, such as n=4, n=8, and n=12, increased gradually under the dilute condition (100 mM K(+)), demonstrating no interaction existed between the individual G-quadruplex units composing of four repeats. Therefore, the reasonable arrangement of the intramolecular G-quadruplexes formed by long telomeric DNAs (n> or =8) was proposed to be a bead-string structure in which the G-quadruplex units were connected each other by one TTA linker. Furthermore, the results of melting experiments demonstrated that thermodynamic stabilities of G-quadruplex structures of the long telomeric DNAs (n=5-12) are mostly independent of sequence length, although telomeric DNA including four repeats (n=4) is more stable than the longer ones. Moreover, the melting temperatures of the G-quadruplexes under the crowding condition (100 mM K(+) and 20 wt% PEG200) are higher than those under the dilute condition, indicating the crowding condition can increase the stability of G-quadruplex. These information are useful for researches of the telomere biology and a better development of therapeutic agents targeting telomeric DNAs.

Characterization of structure and stability of long telomeric DNA G-quadruplexes.

In the current study, we used a combination of gel electrophoresis, circular dichroism, and UV melting analysis to investigate the structure and stability of G-quadruplexes formed by long telomeric DNAs from Oxytricha and human, where the length of the repeat (n)=4 to 12. We found that the Oxytricha telomeric DNAs, which have the sequence (TTTTGGGG)n, folded into intramolecular and intermolecular G-quadruplexes depending on the ionic conditions, whereas human telomeric DNAs, which have the sequence (TTAGGG)n, formed only intramolecular G-quadruplexes in all the tested conditions. We further estimated the thermodynamic parameters of the intramolecular G-quadruplex. We found that thermodynamic stabilities of G-quadruplex structures of long telomeric DNAs (n=5 to 12) are mostly independent of sequence length, although telomeric DNAs are more stable when n=4 than when n>or=5. Most importantly, when n is a multiple of four, the change in enthalpy and entropy for G-quadruplex formation increased gradually, demonstrating that the individual G-quadruplex units are composed of four repeats and that the individual units do not interact. Therefore, we propose that the G-quadruplexes formed by long telomeric DNAs (n>or=8) are bead-on-a-string structures in which the G-quadruplex units are connected by one TTTT (Oxytricha) or TTA (human) linker. These results should be useful for understanding the structure and function of telomeres and for developing improved therapeutic agents targeting telomeric DNAs.

[Genetic diversity of gliadin in wild germplasm of Elymus nutans Griseb].

Acid polyacrylamide gel electrophoresis (A-PAGE) was used to detect the gliadin genetic polymorphism among thirty-three wild accessions of Elymus nutans Griseb collected from four provinces and regions in China (Xinjiang, Qinghai, Sichuan and Tibet). The follows results were obtained. (1) A total of 38 bands were detected in all accessions, 92.1% were polymorphic bands. The average number of Shannon index to four electrophoretic zones was 0.55. The Nei's genetic similarity coefficient of the tested accessions ranged from 0.36 to 0.94, and the average Nei's coefficient was 0.63. These results suggested that there was rich genetic polymorphism among the tested wild resources of Elymus nutans Griseb. (2) 33 wild accessions can be clustered into seven groups at GS = 0.67 level on dendrogram. The principal coordinates (PCA) reflected almost the same relationships among the studied materials as shown in cluster analysis. Moreover, the groups from the same origin frequently clustered into one group. The findings implied that a correlation among gliadin patterns, geographical and ecological environment. (3) Genetic differentiation between and within five eco-geographical groups of Elymus nutans was estimated by Shannon's diversity index, which shown that 42.94% genetic variance existed within group, and 50.76% genetic variance was among groups. This result might be correlative to mainly self-pollinated breeding system of E. nutans. (4) UPGMA cluster analysis based on Nei's unbiased measures of genetic identity was assayed for five geographical groups of Elymus nutans, indicating that there was a significantly positive correlation between genetic differentiation and geographical habits among the five groups.