Cell cycle progression and transmitotic apoptosis resistance promote escape from extrinsic apoptosis

The role of PI3K/Akt signaling pathway in chronic kidney disease

Chronic kidney disease (CKD), including chronic glomerulonephritis, IgA nephropathy and diabetic nephropathy, are common chronic diseases characterized by structural damage and functional decline of the kidneys. The current treatment of CKD is symptom relief. Several studies have reported that the phosphatidylinositol 3 kinases (PI3K)/protein kinase B (Akt) signaling pathway is a pathway closely related to the pathological process of CKD. It can ameliorate kidney damage by inhibiting this signal pathway which is involved with inflammation, oxidative stress, cell apoptosis, epithelial mesenchymal transformation (EMT) and autophagy. This review highlights the role of activating or inhibiting the PI3K/Akt signaling pathway in CKD-induced inflammatory response, apoptosis, autophagy and EMT. We also summarize the latest evidence on treating CKD by targeting the PI3K/Akt pathway, discuss the shortcomings and deficiencies of PI3K/Akt research in the field of CKD, and identify potential challenges in developing these clinical therapeutic CKD strategies, and provide appropriate solutions.

Effectiveness of an "online + in-person" hybrid model for an undergraduate molecular biology lab during COVID-19

The COVID-19 outbreak has created turbulence and uncertainty into multiple aspects of life in countries around the world. In China, the pandemic continues to pose a great challenge to the nature of traditional in-class education in schools. Chinese education has faced the difficult decision of whether to resume in-person teaching in an unprecedented and time-pressured manner. To ensure the quality of teaching and learning during this time, this study aims to explore the effectiveness of an "online + in-person" hybrid teaching model with a new three-part approach to the hybrid teaching lab, where students prepare for the in-person lab using virtual simulated experiments and learning modules and debrief their learning afterwards online as well. This approach not only enhances the efficiency during the in-person lab but also strongly reinforces concepts and laboratory skills by providing a "practice run" before physically attending the lab. A total of 400 medical undergraduates from Dalian Medical University in China were recruited for this study. In an undergraduate molecular biology laboratory course, we observed 200 students in a hybrid teaching model. We evaluated the learning outcomes from the "online + in-person" hybrid teaching model with a questionnaire survey and assessed the quality of experiment execution, report writing, and group collaboration. Moreover, the 200 students from the hybrid group were evaluated during an annual science competition at the university and compared to 200 students from the competition cohort who had no experience with a hybrid learning model. The comparison data were analyzed using a student's t-test statistical analysis. The students in the hybrid learning group demonstrated a strong enthusiasm for the model, high amount of time utilizing the online system, and high scores on laboratory evaluation assignments. Approximately 98% of the hybrid learning students reported that they preferred mixed teaching to the traditional teaching mode, and all students scored above 96% on the online laboratory report. Teachers of the course observed that the hybrid group had a noticeably higher level of proficiency in lab skills compared to the previous students. At the Dalian Medical University annual science competition, where we compared our hybrid group to a traditional learning group, scores for both the objective and subjective items showed that the students instructed with the hybrid lab model had superior performance (p < 0.05). In the context of the COVID-19 pandemic, we developed a new three-part molecular biology laboratory course that strongly improved students' laboratory skills, knowledge retention, and enthusiasm for the course using online learning to improve their learning efficiency and expedite the in-person laboratory experience. We found that these students performed at a higher level in a combined theoretical/practical science competition compared to the students in traditional in-person lab courses. Additionally, our model subjectively fostered enthusiasm and excellence in both teachers and students. Further, cultivation of the students' independent learning and creative problem solving skills were emphasized. The exploration of an effective teaching model, such as the one described here, not only provides students with a solid foundation for their future medical studies and career development but also promotes more efficient in-person laboratory time.

Bcl-xL activity influences outcome of the mitotic arrest

Microtubule-targeting (MT) drugs taxanes and vinca alkaloids are widely used as chemotherapeutic agents against different tumors for more than 30 years because of their ability to block mitotic progression by disrupting the mitotic spindle and activating the spindle assembly checkpoint (SAC) for a prolonged period of time. However, responses to mitotic arrest are different—some cells die during mitotic arrest, whereas others undergo mitotic slippage and survive becoming able for proliferation. Using normal fibroblasts and several cancer cell types we determined two critical doses, T1 and T2, of mitotic inhibitors (nocodazole, Taxol, and vinorelbine). T1 is the maximal dose cells can tolerate undergoing normal division, and T2 is the minimal mitostatic dose, wherein &gt; 90% of mitotic cells are arrested in mitosis. In all studied cell lines after treatment with mitotic inhibitors in a dose above T2 cells had entered mitosis either die or undergo mitotic slippage. We show that for all three drugs used cell death during mitotic arrest and after slippage proceeded via mitochondria-dependent apoptosis. We determined two types of cancer cells: sensitive to mitotic arrest, that is, undergoing death in mitosis (DiM) frequently, and resistant to mitotic arrest, that is, undergoing mitotic slippage followed by prolonged survival. We then determined that inhibition of Bcl-xL, but not other anti-apoptotic proteins of the Bcl-2 group that regulate MOMP, make resistant cells susceptible to DiM induced by mitotic inhibitors. Combined treatment with MT drugs and highly specific Bcl-xL inhibitors A-1155643 or A-1331852 allows achieving 100% DiM in a time significantly shorter than maximal duration of mitotic arrest in all types of cultured cells tested. We further examined efficacy of sequential treatment of cultured cells using mitotic inhibitors followed by inhibitors of Bcl-xL anti-apoptotic protein and for the first time show that sensitivity to Bcl-xL inhibitors rapidly declines after mitotic slippage. Thus sequential use of mitotic inhibitors and inhibitors of Bcl-xL anti-apoptotic protein will be efficient only if the Bcl-xL inhibitor will be added before mitotic slippage occurs or soon afterward. The combined treatment proposed might be an efficient approach to anti-cancer therapy.

Nitazoxanide inhibits osteosarcoma cells growth and metastasis by suppressing AKT/mTOR and Wnt/β-catenin signaling pathways

Osteosarcoma (OS) is the most prevalent malignant bone tumor with poor prognosis. Developing new drugs for the chemotherapy of OS has been a focal point and a major obstacle of OS treatment. Nitazoxanide (NTZ), a conventional anti-parasitic agent, has got increasingly noticed because of its favorable antitumor potential. Herein, we investigated the effect of NTZ on human OS cells in vitro and in vivo. The results obtained in vitro showed that NTZ inhibited the proliferation, migration and invasion, arrested cell cycle at G1 phase, while induced apoptosis of OS cells. Mechanistically, NTZ suppressed the activity of AKT/mTOR and Wnt/β-catenin signaling pathways of OS cells. Consistent with the results in vitro, orthotopic implantation model of 143B OS cells further confirmed that NTZ inhibited OS cells growth and lung metastasis in vivo. Notably, NTZ caused no apparent damage to normal cells/tissues. In conclusion, NTZ may inhibit tumor growth and metastasis of human OS cells through suppressing AKT/mTOR and Wnt/β-catenin signaling pathways.

First person – Nadine Pollak

First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Nadine Pollak is first author on ‘ Cell cycle progression and transmitotic apoptosis resistance promote escape from extrinsic apoptosis’, published in JCS. Nadine conducted the research described in this article while a postdoc at the Institute of Cell Biology and Immunology, University of Stuttgart, Germany, initially under the supervision of Prof. Peter Scheurich and subsequently in the lab of Prof. Markus Rehm, where she is now investigating the mechanisms underlying cell fate decisions in response to death stimuli throughout the cell cycle at the single-cell level.