AMED3001 Cancer
Targeted Therapy, Cell Therapy & Immunotherapy
Week 11 covers modern cancer therapeutics: targeted small molecules and monoclonal antibodies against the driver pathways, cellular therapy (CAR-T), immune-checkpoint inhibitors, and gene and RNA therapy. It contrasts the specificity, side effects and cost of targeted versus conventional treatment, and explains how tumours evade immunity and how checkpoint blockade reverses it. Mechanisms of checkpoint inhibitors, CAR-T and siRNA-versus-CRISPR are common short-answer topics in the final (50%, confirm on Canvas).
What this chapter covers
- 01Conventional vs targeted therapy: specificity, side effects, cost and availability
- 02Targeted small molecules and monoclonal antibodies against driver pathways (trastuzumab; EGFR/BRAF inhibitors)
- 03Antibody-drug conjugates (T-DM1, T-DXd): antibody plus an internalised cytotoxic payload
- 04Tumour immune evasion: checkpoint activation (PD-1/PD-L1, CTLA-4), MDSCs, Tregs, exhausted T cells
- 05Immune-checkpoint inhibitors (anti-PD-1, e.g. pembrolizumab) restore cytotoxic T-cell activity
- 06CAR-T cell therapy: T cells engineered with a chimeric antigen receptor (e.g. Kymriah) for B-cell malignancies
- 07Gene therapy (DNA, permanent; CRISPR-Cas9) vs RNA therapy (RNA, transient; siRNA via RISC)
- 08Delivery: viral vectors (high efficiency, more immunogenic) vs lipid nanoparticles (larger mRNA cargo, fewer immune reactions)
How immune-checkpoint inhibitors restore anti-tumour immunity
- +1Immune checkpoints (e.g. PD-1 on T cells, engaged by PD-L1) are normal ‘brakes’ that switch off T-cell activity to prevent autoimmunity.
- +1Tumours exploit this by expressing PD-L1, which engages PD-1 on cytotoxic T cells and inhibits them, so the T cells become exhausted and fail to kill the cancer — one mechanism of immune evasion.
- +1An anti-PD-1 antibody (pembrolizumab) blocks the PD-1/PD-L1 interaction, releasing the brake on the T cell.
- +1With the checkpoint blocked, cytotoxic T-cell activity is restored and the immune system can attack the tumour; this is effective in cancers such as melanoma and non-small-cell lung cancer, though only a subset of patients achieve durable remission.
Key terms
- Targeted therapy
- Treatment aimed at a specific molecule driving the cancer (a driver pathway, receptor or fusion protein); more specific and lower-toxicity than conventional chemo, but more expensive and of limited availability.
- Immune-checkpoint inhibitor
- An antibody that blocks an inhibitory receptor (e.g. anti-PD-1 pembrolizumab, anti-CTLA-4) to release the brake on cytotoxic T cells and restore anti-tumour immunity.
- CAR-T cell therapy
- A cellular therapy in which a patient's T cells are engineered to express a chimeric antigen receptor recognising a tumour antigen (e.g. Kymriah); used for B-cell leukaemia and lymphoma, still hard to apply to solid tumours.
- siRNA
- A short (21-23 nucleotide) double-stranded RNA whose guide strand is loaded into RISC to cleave a matching mRNA, transiently reducing gene expression; the basis of RNA therapy.
- CRISPR-Cas9
- A gene-editing tool in which a guide RNA directs the Cas9 nuclease to cut a specific DNA sequence, allowing permanent gene modification through the cell's repair machinery.
- Lipid nanoparticle (LNP)
- A synthetic delivery vehicle for gene/RNA therapy; fewer immune reactions and larger mRNA cargo (up to ~22 kb) than viral vectors, but lower transfection efficiency; enabled the COVID-19 mRNA vaccines.
Targeted Therapy, Cell Therapy & Immunotherapy FAQ
How is targeted therapy different from conventional chemotherapy?
Conventional chemotherapy is non-specific, hitting all fast-dividing cells (cancer and healthy) with high side effects but low cost; targeted therapy acts on a specific molecule in the cancer, giving fewer side effects and the prospect of longer remission, but at higher cost and limited availability.
How do checkpoint inhibitors and CAR-T differ?
Checkpoint inhibitors are antibodies that release a natural brake (e.g. PD-1) on the patient's own T cells; CAR-T is a cell therapy that engineers the patient's T cells with a new chimeric antigen receptor to directly recognise a tumour antigen. Both are immunotherapies but act by different routes.
What is the difference between gene therapy and RNA therapy?
Gene therapy edits DNA for a permanent change (e.g. CRISPR-Cas9); RNA therapy targets RNA for a transient change in gene expression (e.g. siRNA acting through RISC to cleave mRNA). ‘Permanent DNA versus transient RNA’ is the phrase to remember.
Can AI help me learn the immunotherapy mechanisms in AMED3001?
Yes — Sia can contrast checkpoint inhibitors, CAR-T, siRNA and CRISPR mechanism by mechanism and quiz you on the delivery-vehicle trade-offs; it explains the method and checks your reasoning rather than doing your assessment.
Exam move
Learn each modern therapy by its precise mechanism and target — checkpoint inhibitors release a T-cell brake, CAR-T engineers a new receptor, siRNA transiently silences mRNA, CRISPR permanently edits DNA — because the exam asks you to distinguish them cleanly. Keep the targeted-versus-conventional contrast (specificity, side effects, cost) and the viral-versus-lipid-nanoparticle delivery trade-offs ready. Ask Sia to quiz mechanism-by-mechanism; keep it warm for the final and confirm details on Canvas.
Working through Targeted Therapy, Cell Therapy & Immunotherapy in AMED3001? Sia is AskSia’s AI Biology tutor — ask any AMED3001 Targeted Therapy, Cell Therapy & Immunotherapy question and get a clear, step-by-step explanation grounded in how AMED3001 is taught and assessed. Read this chapter free, then take your hardest questions to Sia.
