Cellular senescence contributes to tumor regression through both cell autonomous and non-autonomous mechanisms. Drugs inducing cancer cell senescence and modulating senescence-associated secretory phenotype (SASP) render advantage to the cancer treatment. Breast cancer remains the second most cause of female cancer mortality, among which triple-negative breast cancer (TNBC) has a more aggressive clinical course. Our study showed that in TNBC cell lines including MDA-MB-231 and 4T1 cells, moderate concentrations of wogonin (5, 7-dihydroxy-8-methoxy-2-phenyl-4h-1-benzopyran-4-one) (50-100 μM) not only induced permanent proliferation inhibition, but also increased P16 expression, β-galactosidase activity, senescence-associated heterochromatin foci and SASP, which are the typical characteristics of cellular senescence. Moreover, results showed that wogonin-induced senescence was partially attributed to the reactive oxygen species (ROS) accumulation upon wogonin treatment in MDA-MB-231 cells, since elimination of ROS by N-acetylcysteine (NAC) was able to repress wogonin-induced β-galactosidase activity. Mechanistically, wogonin reduced the expression of TXNRD2, an important antioxidant enzyme in controlling the levels of cellular ROS, by altering the histone acetylation at its regulatory region. In addition, senescent MDA-MB-231 cells induced by wogonin exhibited activated NF-κB and suppressed STAT3, which were recognized as regulators of SASP. SASP from these senescent cells suppressed tumor cell growth, promoted macrophage M1 polarization in vitro and increased immune cell infiltration in xenografted tumors in vivo. These results reveal another mechanism for the anti-breast cancer activity of wogonin by inducing cellular senescence, which suppresses tumor progression both autonomously and non-autonomously.
Bromodomain-containing 4 (BRD4), a member of Bromo and Extra-Terminal (BET) family, recognizes acetylated histones and is of importance in transcription, replication, and DNA repair. It also binds non-histone proteins, DNA and RNA, contributing to development, tissue growth, and various physiological processes. Additionally, BRD4 has been implicated in driving diverse diseases, ranging from cancer, viral infection, inflammation to neurological disorders. Inhibiting its functions with BET inhibitors (BETis) suppresses the progression of several types of cancer, creating an impetus for translating these chemicals to the clinic. The diverse roles of BRD4 are largely dependent on its interaction partners in different contexts. In this review we discuss the molecular mechanisms of BRD4 with its interacting partners in physiology and pathology. Current development of BETis is also summarized. Further understanding the functions of BRD4 and its partners will facilitate resolving the liabilities of present BETis and accelerate their clinical translation.
With the use of low-dose CT for early screening of lung cancer, more and more early lung cancers are found. At the same time, patients with small lung nodules have also increased, it is a great challenge for surgeons to resect pulmonary nodules with small volume, deep position and no solid components under video-assisted thoracoscopic surgery. Many studies have reported preoperative and intraoperative methods for localizing lung nodules before minimally invasive resection. Methods for preoperative localization include CT-guided hook-wire positioning, coil positioning, or dye injection and radionuclide location Methods for intraoperative localization include intraoperative ultrasound localization and tactile pressure-sensing localization. After the localization of pulmonary nodules under the guidance of CT patients need to restrict their activities; otherwise, it is easy for the nodules to move, causing the operation to fail, and may also cause complications such as pneumothorax, puncture site pain, and pulmonary parenchymal bleeding. In the past, we injected melamine dye under the guidance of electromagnetic navigation bronchoscope to locate lung nodules. The purpose of this case is introducing a new method for accurately localizing and resecting pulmonary nodules by injecting indocyanine green (ICG) under the guidance of electromagnetic navigation bronchoscope and the resection of small pulmonary nodules under the fluoroscope.
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