Advances in the molecular mechanism and targeted therapy of radioactive-iodine refractory differentiated thyroid cancer.

Most patients with differentiated thyroid cancer have a good prognosis after radioactive iodine-131 treatment, but there are still a small number of patients who are not sensitive to radioiodine treatment and may subsequently show disease progression. Therefore, radioactive-iodine refractory differentiated thyroid cancer treated with radioiodine usually shows reduced radioiodine uptake. Thus, when sodium iodine symporter expression, basolateral membrane localization and recycling degradation are abnormal, radioactive-iodine refractory differentiated thyroid cancer may occur. In recent years, with the deepening of research into the pathogenesis of this disease, an increasing number of molecules have become or are expected to become therapeutic targets. The application of corresponding inhibitors or combined treatment regimens for different molecular targets may be effective for patients with advanced radioactive-iodine refractory differentiated thyroid cancer. Currently, some targeted drugs that can improve the progression-free survival of patients with radioactive-iodine refractory differentiated thyroid cancer, such as sorafenib and lenvatinib, have been approved by the FDA for the treatment of radioactive-iodine refractory differentiated thyroid cancer. However, due to the adverse reactions and drug resistance caused by some targeted drugs, their application is limited. In response to targeted drug resistance and high rates of adverse reactions, research into new treatment combinations is being carried out; in addition to kinase inhibitor therapy, gene therapy and rutin-assisted iodine-131 therapy for radioactive-iodine refractory thyroid cancer have also made some progress. Thus, this article mainly focuses on sodium iodide symporter changes leading to the main molecular mechanisms in radioactive-iodine refractory differentiated thyroid cancer, some targeted drug resistance mechanisms and promising new treatments.

In vitro antifungal activity of lasiodiplodin, isolated from endophytic fungus Lasiodiplodia pseudotheobromae J-10 associated with Sarcandra glabra and optimization of culture conditions for lasiodiplodin production.

A macrolide antibiotic, lasiodiplodin was isolated from the endophytic fungus (EF) Lasiodiplodia pseudotheobromae J-10 associated with the medicinal plant Sarcandra glabra. In vitro antifungal assay demonstrated the inhibitory activity of lasiodiplodin against the growth of six phytopathogenic fungi, with the IC50 values ranging between 15.50 and 52.30 µg/mL. The highest antifungal activities were recorded against Exserohilum turcicum, Colletotrichum capsici, and Pestalotiopsis theae, with IC50 values of 15.50, 15.90, and 17.55 µg/mL, respectively. The underlying mechanism of the antifungal activity of lasiodiplodin against E. turcicum included the alteration of its colony morphology and disturbance of its cell membrane integrity. In addition, the optimization of L. pseudotheobromae J-10 culture conditions increased lasiodiplodin yield to 52.33 mg/L from 0.59 mg/L at pre-optimization. This is the first report on the isolation and identification of antifungal compound from the EF L. pseudotheobromae J-10 associated with S. glabra, as well as on the optimization of L. pseudotheobromae J-10 culture conditions to increase lasiodiplodin yield. The results of this study support that lasiodiplodin is a natural compound with high potential bioactivity against phytopathogens, and provide a basis for further study of the EF associated with S. glabra.

SYKT Alleviates Doxorubicin-Induced Cardiotoxicity via Modulating ROS-Mediated p53 and MAPK Signal Pathways.

Backgrounds. Doxorubicin (DOX) is an effective therapeutic drug for malignant tumors; however, its clinical applications were limited by its side effects, especially the cardiotoxicity caused by ROS-mediated p53 and MAPK signal pathways' activation-induced cell apoptosis. Sanyang Xuedai mixture (SYKT) has been reported as an antioxidant agent and attenuated DOX-induced cardiotoxicity by targeting ROS-mediated apoptosis, but the mechanisms are still not fully delineated. Objective. This study aimed at investigating whether SYKT alleviated DOX-induced cardiotoxicity by inhibiting ROS-mediated apoptosis and elucidating the role of ROS-mediated p53 and MAPK signal pathways' activation in this process. Materials and Methods. Identification, separation, and culture of mouse primary cardiomyocytes. Cells were treated with DOX (1 µM), SYKT (30 mg/mL), or SYKT coupled with DOX. The p53 inhibitor Pifithrin-α (PFT-α), p38/MAPK inhibitor SB203583 (SB), and JNK inhibitor SP600125 (SP) were used as positive control. Western blot was employed to detected p53 and p38 as well as JNK expressions and the activation and translocation of Bax and cytochrome C. Flow cytometer (FCM) was used to detect the mitochondrial membrane potential and cell apoptosis. Results. After separation and culture, 95% of cells showed positive cTnI expression, which indicated that mouse primary cardiomyocytes were successfully identified in our research. DOX activated p53 and MAPK signal pathways in a time-dependent manner, which were inactivated by being cotreated with SYKT, PFT-α, or SB, respectively. DOX significantly decreased Bax and increased cytochrome c expressions in the cytoplasm, whereas Bax was upregulated and cytochrome c was downregulated in the mitochondria, which were reversed by SYKT treatment. Besides, DOX reduced mitochondria membrane potential (MMP) in cardiomyocytes compared to the control group; SYKT recovered its MMP and attenuated DOX-induced cardiomyocyte injury. Of note, DOX increased the expression levels of cleaved caspase-3 as well as poly ADP-ribose polymerase (PARP) and promoted cell apoptosis, which were also reversed by SYKT treatment. Discussion and Conclusions. Our results indicated that SYKT alleviated DOX-induced cardiotoxicity by inhibiting p53 and MAPK signal pathways' activation-mediated apoptosis, and it might serve as a potential therapeutic agent for DOX-induced cardiotoxicity.

A herbal formula, SYKT, reverses doxorubicin­induced myelosuppression and cardiotoxicity by inhibiting ROS­mediated apoptosis.

Doxorubicin (DOX) is an antineoplastic drug widely used for the treatment of various types of cancer; however, it can induce severe side effects, such as myelosuppression and cardiotoxicity. Sanyang Xuedai (SYKT) is a natural medicine originating from an ancient prescription of the Dai nationality in Southwest China. With eight Chinese herbal medicines, including sanguis draconis, radix et rhizoma notoginseng, radix et rhizoma glycyrrhizae and radix angelicae sinensis as the primary ingredients, SYKT has been reported to possess numerous biological functions. The present study investigated whether SYKT can confer protection against DOX­induced myelosuppression and cardiotoxicity, and explored the potential mechanism involved. Mice were treated with DOX, SYKT or a combination of the two; hematopoietic functions were assessed by measuring the number of peripheral blood cells, cluster of differentiation CD34+/CD44+ bone marrow cells and apoptotic cells. Myocardial enzymes, including aspartate aminotransferase, lactate dehydrogenase, creatine kinase (CK) and its isoform CK­MB, were assessed using a biochemical analyzer. The apoptotic rate of cardiomyocytes was assessed using flow cytometry. Histopathological analysis was conducted using hematoxylin­eosin staining. Intracellular reactive oxygen species (ROS) production was evaluated using a dichlorofluorescein intensity assay. The mice treated with DOX exhibited a reduced survival rate, reduced peripheral blood and CD34+/CD44+ cell counts, elevated myocardial enzymes and apoptotic indices in bone marrow cells and cardiomyocytes, all of which were effectively prevented by SYKT co­administration. Furthermore, bone marrow cells and myocytes from mice treated with DOX demonstrated increased dichlorofluorescein intensity, which was attenuated by SYKT. Notably, SYKT did not interfere with the effects of DOX on tumor volume or the induction of tumor cell apoptosis in tumor­bearing mice. The present study indicated that SYKT may counteract DOX­induced myelosuppression and cardiotoxicity through inhibiting ROS­mediated apoptosis. These findings suggested that SYKT may have potential as a means to counteract the potentially fatal hematopoietic and cardiac complications associated with DOX treatment.

Yin Yang 1 plays an essential role in breast cancer and negatively regulates p27.

Yin Yang 1 (YY1) is highly expressed in various types of cancers and regulates tumorigenesis through multiple pathways. In the present study, we evaluated YY1 expression levels in breast cancer cell lines, a breast cancer TMA, and two gene arrays. We observed that, compared with normal samples, YY1 is generally overexpressed in breast cancer cells and tissues. In functional studies, depletion of YY1 inhibited the clonogenicity, migration, invasion, and tumor formation of breast cancer cells, but did not affect the clonogenicity of nontumorigenic cells. Conversely, ectopically expressed YY1 enhanced the migration and invasion of nontumorigenic MCF-10A breast cells. In both a monolayer culture condition and a three-dimensional Matrigel system, silenced YY1 expression changed the architecture of breast cancer MCF-7 cells to that resembling MCF-10A cells, whereas ectopically expressed YY1 in MCF-10A cells had the opposite effect. Furthermore, we detected an inverse correlation between YY1 and p27 expression in both breast cancer cells and xenograft tumors with manipulated YY1 expression. Counteracting the changes in p27 expression attenuated the effects of YY1 alterations on these cells. In addition, YY1 promoted p27 ubiquitination and physically interacted with p27. In conclusion, our data suggest that YY1 is an oncogene and identify p27 as a new target of YY1.

Yin Yang 1: a multifaceted protein beyond a transcription factor.

As a transcription factor, Yin Yang 1 (YY1) regulates the transcription of a dazzling list of genes and the number of its targets still mounts. Recent studies revealed that YY1 possesses functions independent of its DNA binding activity and its regulatory role in tumorigenesis has started to emerge.

PIASy-mediated sumoylation of Yin Yang 1 depends on their interaction but not the RING finger.

As a multifunctional protein, Yin Yang 1 (YY1) has been demonstrated to regulate both gene expression and protein posttranslational modifications. However, gaps still exist in our knowledge of how YY1 can be modified and what the consequences of its modifications are. Here we report that YY1 protein can be sumoylated both in vivo and in vitro. We have identified lysine 288 as the major sumoylation site of YY1. We also discovered that PIASy, a SUMO E3 ligase, is a novel YY1-interacting protein and can stimulate the sumoylation of YY1 both in vitro and in vivo. Importantly, the effects of PIASy mutants on in vivo YY1 sumoylation correlate with the YY1-PIASy interaction but do not depend on the RING finger domain of PIASy. This regulation is unique to YY1 sumoylation because PIASy-mediated p53 sumoylation still relies on the integrity of PIASy, which is also true of all of the previously identified substrates of PIASy. In addition, PIASy colocalizes with YY1 in the nucleus, stabilizes YY1 in vivo, and differentially regulates YY1 transcriptional activity on different target promoters. This study demonstrates that YY1 is a target of SUMOs and reveals a novel feature of a SUMO E3 ligase in the PIAS family that selectively stimulates protein sumoylation independent of the RING finger domain.