Mitotic Cycle Regulation. I. Oscillations and Bistability

2021 ◽  
pp. 1-17
Author(s):  
John J. Tyson
1998 ◽  
Vol 9 (4) ◽  
pp. 795-807 ◽  
Author(s):  
Alasdair MacAuley ◽  
James C. Cross ◽  
Zena Werb

Differentiation of trophoblast giant cells in the rodent placenta is accompanied by exit from the mitotic cell cycle and onset of endoreduplication. Commitment to giant cell differentiation is under developmental control, involving down-regulation of Id1and Id2, concomitant with up-regulation of the basic helix-loop-helix factor Hxt and acquisition of increased adhesiveness. Endoreduplication disrupts the alternation of DNA synthesis and mitosis that maintains euploid DNA content during proliferation. To determine how the mammalian endocycle is regulated, we examined the expression of the cyclins and cyclin-dependent kinases during the transition from replication to endoreduplication in the Rcho-1 rat choriocarcinoma cell line. We cultured these cells under conditions that gave relatively synchronous endoreduplication. This allowed us to study the events that occur during the transition from the mitotic cycle to the first endocycle. With giant cell differentiation, the cells switched cyclin D isoform expression from D3 to D1 and altered several checkpoint functions, acquiring a relative insensitivity to DNA-damaging agents and a coincident serum independence. The initiation of S phase during endocycles appeared to involve cycles of synthesis of cyclins E and A, and termination of S was associated with abrupt loss of cyclin A and E. Both cyclins were absent from gap phase cells, suggesting that their degradation may be necessary to allow reinitiation of the endocycle. The arrest of the mitotic cycle at the onset of endoreduplication was associated with a failure to assemble cyclin B/p34cdk1complexes during the first endocycle. In subsequent endocycles, cyclin B expression was suppressed. Together these data suggest several points at which cell cycle regulation could be targeted to shift cells from a mitotic to an endoreduplicative cycle.


2019 ◽  
Vol 1 (1) ◽  
pp. 7
Author(s):  
R Nahrowi ◽  
A Setiawan ◽  
Noviany Noviany ◽  
I Sukmana ◽  
S D Yuwono

Paclitaxel is one of the cancer drugs that often used. These drug kills cancer cells byinhibiting mitotic cycle. The efficiency of paclitaxel is increased by the use ofnanomaterials as a carrier of paclitaxel. Nanomaterials can enhance encapsulationefficiency, improve the drug release to the target cell following nanomaterialdegradation, and improve local accumulation of drug in the cell through endocytosisreceptor. Nanomaterial that often used forencapsulation of paclitaxel is a polymerderived from natural resources such as cellulose. The advantages of cellulose as acarrier of paclitaxel are nontoxic, biodegradable, and very abundant from varioussources. One of the potential sources of cellulose for drug delivery system is cassavabaggase.Keywords: Paclitaxel, encapsulation, cell viability, nanocellulose


Author(s):  
Shamim Mushtaq

Uninhibited proliferation and abnormal cell cycle regulation are the hallmarks of cancer. The main role of cyclin dependent kinases is to regulate the cell cycle and cell proliferation. These protein kinases are frequently down regulated or up regulated in various cancers. Two CDK family members, CDK 11 and 12, have contradicting views about their roles in different cancers. For example, one study suggests that the CDK 11 isoforms, p58, inhibits growth of breast cancer whereas, the CDK 11 isoform, p110, is highly expressed in breast tumor. Studies regarding CDK 12 show variation of opinion towards different parts of the body, however there is a consensus that upregulation of cdk12 increases the risk of breast cancer. Hence, CDK 11 and CDK 12 need to be analyzed to confirm their mechanism and their role regarding therapeutics, prognostic value, and ethnicity in cancer. This article gives an outline on both CDKs of information known up to date from Medline, PubMed, Google Scholar and Web of Science search engines, which were explored and thirty relevant researches were finalized.


2020 ◽  
Vol 16 (8) ◽  
pp. 1022-1043
Author(s):  
Imran Khan ◽  
Sadaf Mahfooz ◽  
Mustafa A. Hatiboglu

Background: Glioblastoma is one of the most aggressive and devastating tumours of the central nervous system with short survival time. Glioblastoma usually shows fast cell proliferation and invasion of normal brain tissue causing poor prognosis. The present standard of care in patients with glioblastoma includes surgery followed by radiotherapy and temozolomide (TMZ) based chemotherapy. Unfortunately, these approaches are not sufficient to lead a favorable prognosis and survival rates. As the current approaches do not provide a long-term benefit in those patients, new alternative treatments including natural compounds, have drawn attention. Due to their natural origin, they are associated with minimum cellular toxicity towards normal cells and it has become one of the most attractive approaches to treat tumours by natural compounds or phytochemicals. Objective: In the present review, the role of natural compounds or phytochemicals in the treatment of glioblastoma describing their efficacy on various aspects of glioblastoma pathophysiology such as cell proliferation, apoptosis, cell cycle regulation, cellular signaling pathways, chemoresistance and their role in combinatorial therapeutic approaches was described. Methods: Peer-reviewed literature was extracted using Pubmed, EMBASE Ovid and Google Scholar to be reviewed in the present article. Conclusion: Preclinical data available in the literature suggest that phytochemicals hold immense potential to be translated into treatment modalities. However, further clinical studies with conclusive results are required to implement phytochemicals in treatment modalities.


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