Podcast
Questions and Answers
What occurs during the G2 phase of the cell cycle?
What occurs during the G2 phase of the cell cycle?
- Structures needed for division are made (correct)
- DNA is copied
- Chromosomes are aligned at the cell equator
- Chromatin condenses into chromosomes
Which phase immediately follows G2 in the cell cycle?
Which phase immediately follows G2 in the cell cycle?
- M phase (correct)
- G1 phase
- S phase
- Prophase
Which component directly participates in inhibiting the G2/M transition?
Which component directly participates in inhibiting the G2/M transition?
- Effectors (correct)
- Transducers
- Sensors
- Mediators
Which of the following is crucial for the regulation of the cell cycle at checkpoints?
Which of the following is crucial for the regulation of the cell cycle at checkpoints?
Which of the following is not a phase of mitosis?
Which of the following is not a phase of mitosis?
What is the role of DNA damage checkpoints in human cells?
What is the role of DNA damage checkpoints in human cells?
What percentage of breast cancers will become resistant to hormone therapies?
What percentage of breast cancers will become resistant to hormone therapies?
What is a consequence of CDK4/6 inhibitors in the treatment of breast cancer?
What is a consequence of CDK4/6 inhibitors in the treatment of breast cancer?
Which drug is a CDK4/6 inhibitor?
Which drug is a CDK4/6 inhibitor?
What is the effect of adding ribociclib to hormonal therapy in postmenopausal women with HR+ metastatic breast cancer?
What is the effect of adding ribociclib to hormonal therapy in postmenopausal women with HR+ metastatic breast cancer?
How much did the sales of Palbociclib increase from 2017 to 2018?
How much did the sales of Palbociclib increase from 2017 to 2018?
What is one of the primary mechanisms causing resistance to hormone therapies in breast cancer?
What is one of the primary mechanisms causing resistance to hormone therapies in breast cancer?
What was the total sales amount of Palbociclib in 2018?
What was the total sales amount of Palbociclib in 2018?
What is the main function of estrogen receptor alpha when bound by estrogen?
What is the main function of estrogen receptor alpha when bound by estrogen?
Which phase of the cell cycle involves DNA replication?
Which phase of the cell cycle involves DNA replication?
In which sub-phase of mitosis does the cell's nucleus divide?
In which sub-phase of mitosis does the cell's nucleus divide?
What occurs during the G1 phase of the cell cycle?
What occurs during the G1 phase of the cell cycle?
What is the purpose of the S-phase DNA-damage checkpoint?
What is the purpose of the S-phase DNA-damage checkpoint?
Which stage of the cell cycle directly results in the formation of two daughter cells?
Which stage of the cell cycle directly results in the formation of two daughter cells?
Which of the following is not a phase of interphase?
Which of the following is not a phase of interphase?
What is the primary activity in the G2 phase of the cell cycle?
What is the primary activity in the G2 phase of the cell cycle?
When does the cell 'double check' the duplicated chromosomes for errors?
When does the cell 'double check' the duplicated chromosomes for errors?
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.
