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What occurs during the G2 phase of the cell cycle?
Which phase immediately follows G2 in the cell cycle?
Which component directly participates in inhibiting the G2/M transition?
Which of the following is crucial for the regulation of the cell cycle at checkpoints?
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Which of the following is not a phase of mitosis?
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What is the role of DNA damage checkpoints in human cells?
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What percentage of breast cancers will become resistant to hormone therapies?
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What is a consequence of CDK4/6 inhibitors in the treatment of breast cancer?
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Which drug is a CDK4/6 inhibitor?
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What is the effect of adding ribociclib to hormonal therapy in postmenopausal women with HR+ metastatic breast cancer?
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How much did the sales of Palbociclib increase from 2017 to 2018?
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What is one of the primary mechanisms causing resistance to hormone therapies in breast cancer?
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What was the total sales amount of Palbociclib in 2018?
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What is the main function of estrogen receptor alpha when bound by estrogen?
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Which phase of the cell cycle involves DNA replication?
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In which sub-phase of mitosis does the cell's nucleus divide?
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What occurs during the G1 phase of the cell cycle?
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What is the purpose of the S-phase DNA-damage checkpoint?
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Which stage of the cell cycle directly results in the formation of two daughter cells?
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Which of the following is not a phase of interphase?
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What is the primary activity in the G2 phase of the cell cycle?
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When does the cell 'double check' the duplicated chromosomes for errors?
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Study Notes
Treatment Resistant Breast Cancer
- 1 in 3 breast cancers become resistant to hormone therapies due to crosstalk between intracellular signalling pathways.
- Combination therapy with CDK4/6 inhibitors, such as ribociclib and palbociclib, may offer a solution.
CDK4/6 Inhibitors
- CDK4/6 inhibitors block phosphorylation of Rb, leading to G1 arrest.
- They decrease the appearance of resistance to hormonal chemotherapy.
Estrogen Receptor Signalling
- The main ER pathway involves estrogen binding to estrogen receptor a, triggering gene transcription.
- The secondary ER pathway is also involved.
Combination Therapy
- Adding ribociclib to hormonal therapy in postmenopausal women with hormone-receptor positive (HR+) metastatic breast cancer improves progression-free survival (PFS) by 44%.
- Palbociclib also improves PFS and overall response to therapy.
Cell Cycle
- The cell cycle is the series of events leading to cell division and duplication.
- It involves DNA replication, growth, and preparation for cell division.
Phases of the Cell Cycle
- Interphase: G1, S, G2 phases, where the cell grows and prepares for cell division.
- Mitosis (M-phase): Karyokinesis (nuclear division) and Cytokinesis (cytoplasmic division).
Sub-phases of the Cell Cycle
- G1: primary growth phase, cell grows and synthesizes proteins and organelles.
- S: synthesis phase, DNA is replicated.
- G2: secondary growth phase, cell continues to grow and prepares for mitosis.
- M: mitosis, replicated chromosomes are separated and distributed to daughter cells.
- C: cytokinesis, cytoplasm divides, forming two daughter cells.
DNA Replication
- DNA is replicated in S-phase, and errors are checked and repaired.
- Each of the 46 chromosomes is duplicated by the cell.
G1 and G2 Phases
- G1: integrity of DNA is checked, damage is repaired, and checkpoint R ensures proper progression.
- G2: structures needed for division are made, and the G2-phase checkpoint ensures correct chromosome complement and checks for DNA damage.
Mitosis Phase
- Prophase, prometaphase, metaphase, anaphase, telophase, and cytokinesis occur in sequence.
Control of Cell Cycle Progression
- The cell cycle is regulated by checkpoints controlled by a family of proteins, including cyclins and cyclin-dependent kinases (Cdks).
Cell Cycle Regulation
- Cyclins and Cdks regulate the cell cycle.
- Checkpoints, including DNA damage and replication stress, control cell cycle progression.
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Description
This quiz covers the mechanisms of treatment resistant breast cancer, including crosstalk between intracellular signalling pathways and the role of CDK4/6 inhibitors in overcoming resistance to hormone therapies. Topics include Ribociclib, Palbociclib, and estrogen receptor signalling.
