Anti-Cancer & Anti-Microbial Mechanisms (ACAM) Comprehensive Review

Comprehensive vocabulary flashcards covering cancer immunotherapy, traditional chemotherapeutic agents, targeted PROTAC therapies, hepatic p53-mediated senescence transmission, antimicrobial resistance and tolerance mechanisms, photodynamic therapy principles, and antimalarial pharmacology.

Cancer Immunoediting

The dynamic process whereby the immune system interacts with tumor cells, comprising three sequential phases: elimination (immunosurveillance destroys nascent transformed cells), equilibrium (immune selection holds tumor growth dormant), and escape (immunosubversion allows tumor cells to evade immune destruction and grow progressively).

Hybridoma Technology

A laboratory method used to produce identical monoclonal antibodies by fusing antibody-forming B cells isolated from an immunized mouse's spleen with immortal cultivated tumor cells (myeloma cells), followed by screening and cloning.

CTLA-4 Checkpoint Blockade

A therapeutic strategy using an anti-CTLA-4 monoclonal antibody to block the interaction between CTLA-4 on T cells and B7-1/B7-2 on antigen-presenting cells, thereby restoring co-stimulatory CD28 signaling to activate T-cell mediated killing of tumor cells and deplete regulatory T (Treg) cells.

TIM-3 (T Cell Immunoglobulin and Mucin Domain 3)

An inhibitory immune checkpoint receptor that interacts with galectin-9 on tumor cells to induce T-cell apoptosis; it is also upregulated on regulatory T cells (Tregs) to favor tumor immune evasion and is targeted therapeutically by the antibody sabatolimab.

Rituximab Mechanisms of Action

A therapeutic monoclonal antibody targeting CD20 on B cells that destroys malignant B cells via antibody-dependent cellular cytotoxicity (ADCC), direct cross-linking leading to apoptosis, complement-dependent cytotoxicity (CDC) via C1q recruitment and membrane attack complex assembly, and macrophage phagocytosis via opsonization.

Cetuximab

A monoclonal antibody that acts as an Epidermal Growth Factor Receptor (EGFR) inhibitor, preventing ligand-induced receptor phosphorylation and blocking downstream PI3K/Akt and MAPK kinase cascades to inhibit angiogenesis, cellular proliferation, and migration in colorectal and squamous head and neck cancers.

Trastuzumab (Herceptin)

A humanized mouse monoclonal antibody used for passive immunization against HER2-positive breast cancers that binds the overexpressed HER2/neu receptor, blocking oncogenic growth signaling and recruiting NK cells via Fc$\gamma$R to mediate ADCC.

Viro-Immunotherapy (Oncolytic Viruses)

The use of engineered viruses (e.g., Herpesvirus, Adenovirus, Vaccinia) that selectively infect tumor cells via receptor-mediated cell targeting, replicate within rapidly dividing cells with defective antiviral IFN/TNF pathways, and trigger cell lysis, releasing tumor antigens and cytokines to stimulate an adaptive anti-tumor immune response.

Chimeric Antigen Receptor (CAR) T-Cell Therapy

An adoptive cell transfer (ACT) method where patient T cells are isolated from blood, genetically engineered in the laboratory to express a synthetic chimeric antigen receptor directed against a specific tumor surface antigen (e.g., BCMA or CD19), expanded into millions of cells, and infused back into the patient to destroy tumor cells.

Cancer Vaccines

Active immunotherapy formulations categorized into cell-based (dendritic cell or whole tumor cell), viral-based, peptide-based (antigenic epitopes), or nucleic acid-based (mRNA or DNA) platforms designed to present tumor-associated antigens to antigen-presenting cells and stimulate a cytotoxic T-cell response.

Immunotoxin

A targeted therapeutic conjugate consisting of a tumor-specific monoclonal antibody chemically linked to a toxic biological payload, radioisotope, or pro-drug that binds to cell-surface antigens, internalizes, and delivers localized cytotoxic damage.

DRP-104

A pro-drug of the active glutamine antagonist DON that is selectively cleaved in tumor tissue, delivering $11$ times more active drug to the tumor compared to the gut, thereby reducing systemic gastrointestinal toxicities.

Cancer Chemotherapy

The systemic pharmacological administration of cytotoxic or targeted drugs to inhibit cell division or directly kill malignant cells throughout the body, first introduced over $70$ years ago with nitrogen mustards and folate antagonists.

Bifunctional Alkylating Agents

Cytotoxic chemotherapeutics featuring two reactive chloroethyl groups that form reactive carbonium ion intermediates, forming covalent interstrand and intrastrand cross-links between nucleophilic N7 positions of guanine and adenine bases to inhibit DNA replication and RNA transcription.

Mustine (Mechlorethamine)

A bis(chloroethyl)amine and stable derivative of World War I mustard gas developed in 1942 by Alfred Goodman and Louis Gilman; identified as the first anticancer chemotherapeutic drug after autopsies showed severe lymphoid and myeloid suppression in victims.

Cyclophosphamide

A nitrogen mustard alkylating pro-drug metabolized by hepatic cytochrome P450 mixed-function oxidases into active phosphoramide mustard and the toxic metabolite acrolein, widely used in treating breast cancer, Burkitt's lymphoma, and multiple myeloma.

Carmustine

A highly lipophilic nitrosourea alkylating agent capable of crossing the blood-brain barrier, administered intravenously or as intracranial biodegradable polymer wafer implants following surgical resection of brain and meningeal tumors.

Cisplatin

An inorganic platinum compound that reacts with nucleophilic sites on DNA to form cross-links that block replication and transcription, while generating oxidative stress that activates pro-apoptotic MAP kinase pathways; resistance commonly emerges through decreased CTR1 expression or increased metallothionein.

Lipoplatin

A lipid nanoparticle formulation of cisplatin encapsulated within dipalmitoyl phosphatidyl glycerol (DPPG) and coated with polyethylene glycol (PEG), extending plasma half-life from $6\text{ hours}$ to $120\text{ hours}$ and accumulating selectively in leaky tumor vasculature via the EPR effect.

Methotrexate

A folate antimetabolite structurally analogous to folic acid that binds competitively to the active site of dihydrofolate reductase (DHFR), blocking conversion of FH2 to FH4 and arresting thymidylate and purine synthesis.

5-Fluorouracil (5-FU)

A pyrimidine antimetabolite converted intracellularly into FUTP and FdUTP; FdUTP inhibits thymidylate synthase to suppress DNA synthesis, while FUTP integrates into RNA to perturb mRNA processing and induce apoptosis.

Cytarabine (ara-C)

A false metabolite analog of deoxycytidine that is metabolized into cytosine arabinoside triphosphate, which inhibits DNA and RNA polymerases and ribonucleotide reductase and is directly incorporated into DNA to cause chain termination.

Mercaptopurine (6-MP)

A purine antimetabolite analog of adenine that inhibits early de novo purine ring biosynthesis and nucleotide interconversions, and integrates directly into DNA to disrupt replication in rapidly proliferating cells.

Taxanes

Plant-derived antimicrotubule agents (paclitaxel from Pacific Yew, docetaxel from European Yew) that bind the N-terminal region of polymerized $\beta$-tubulin, hyper-stabilizing microtubules against depolymerization and arresting the cell cycle in metaphase.

Vinca Alkaloids

Natural compounds from Catharanthus roseus (vincristine, vinblastine) that bind the Vinca-binding domain of $\beta$-tubulin, preventing microtubule assembly and triggering spindle depolymerization to halt mitosis.

P-glycoprotein (MDR1 / ABCB1)

An ATP-dependent membrane efflux transporter belonging to the ABC-transporter superfamily that pumps out diverse lipophilic chemotherapeutics (such as taxanes, vinca alkaloids, and anthracyclines), conferring multidrug resistance.

Anthracyclines

Antitumor antibiotics (doxorubicin, daunorubicin) isolated from Streptomyces peucetius that act by intercalating between DNA base pairs, stabilizing the cleaved DNA-topoisomerase II$\alpha$ complex to prevent religation, and generating cytotoxic reactive oxygen species through quinone reduction.

L-Asparaginase

An enzymatic therapy that hydrolyzes circulating L-asparagine into L-aspartic acid and ammonia, selectively starving acute lymphoblastic leukemia (ALL) and AML cells that lack asparagine synthetase.

PROTAC (Proteolysis Targeting Chimera)

A heterobifunctional molecule comprising a target protein of interest (POI) ligand and an E3 ubiquitin ligase ligand joined by a chemical linker; it brings the POI and E3 ligase into close proximity to facilitate polyubiquitination and 26S proteasome-mediated degradation, after which the PROTAC is recycled.

CBPD-409

A pre-clinical PROTAC consisting of the CBP/p300 bromodomain inhibitor GNE-049 linked to thalidomide (a cereblon/CRBN ligand), demonstrating nanomolar-potency targeted degradation of CBP/p300 and suppression of c-MYC in multiple myeloma and prostate cancer.

CBP/p300

Paralogous lysine acetyltransferases (KATs) and transcriptional co-activators containing bromodomains (BD) that 'read' and KAT domains that 'write' acetyl marks on histones (such as H2AZ and H4), driving essential oncogenic networks (e.g., IRF4/c-MYC) required for multiple myeloma cell proliferation and fitness.

Inobrodib (CCS1477)

A small-molecule bromodomain inhibitor targeting CBP/p300 that modestly reduces lysine acetylation of target genes without degrading the co-activator protein complex.

ESR1 Mutation

Acquired genetic alterations in the estrogen receptor alpha gene (such as Y537S) that drive ligand-independent receptor activation, shorten overall survival, and confer resistance to standard endocrine therapies (tamoxifen) and degraders (fulvestrant) in advanced breast cancer.

Vepdegestrant (ARV-471)

An orally bioavailable, FDA-approved PROTAC degrading estrogen receptor alpha (ER$\alpha$) by linking a lasofoxifene-derived SERM moiety to a lenalidomide CRBN-binding ligand; indicated for ER+/HER2-, ESR1-mutated advanced or metastatic breast cancer.

Cellular Senescence

A permanent, irreversible state of cell cycle arrest characterized by the expression of senescence-associated beta-galactosidase (SA-$\beta$-gal), elevated p21/CDKN1A and p16/CDKN2A, persistent DNA damage signaling (p-H2AX S139), and secretion of a pro-inflammatory Senescence-Associated Secretory Phenotype (SASP).

MDM2 (Mouse Double Minute 2)

A negative regulator of p53 that suppresses p53 activity via an E3-ubiquitin ligase-dependent RING finger domain that ubiquitinates p53 for proteasomal degradation, and via an E3-independent domain that directly binds the p53 N-terminus to block transcriptional activation.

MDM2 FL/FL Murine Model

A conditional transgenic mouse model featuring Cre-loxP-mediated deletion of MDM2 exons 5 and 6 via hepatocyte-specific AAV8-TBG-Cre; total loss of MDM2 triggers lethal acute liver failure within $4\text{ to }6\text{ days}$ driven by runaway p53 activation and secondary transmission of senescence.

MDM2 I438K Murine Model

A transgenic mouse strain bearing an isoleucine-to-lysine point mutation at residue 438 that selectively ablates MDM2's E3 ubiquitin ligase catalytic activity while preserving its direct physical binding to the p53 N-terminus.

HFHSHC Diet MASH Model

A dietary model using a high-fat, high-sugar, high-cholesterol diet in male reporter mice that activates hepatic p53, drives metabolic dysfunction-associated steatohepatitis (MASH) with elevated ALT and fibrosis (PSR), and causes SASP-mediated transmission of senescence to the lungs, kidneys, and brain.

Minimum Inhibitory Concentration (MIC)

The lowest concentration of an antimicrobial agent ($\mu\text{g/mL}$) that completely prevents visible in vitro growth of a specific bacterial isolate, categorized by clinical standards (EUCAST, CLSI) into susceptible, intermediate, and resistant breakpoints.

Transpeptidase

A bacterial penicillin-binding protein (PBP) essential for cell wall synthesis that catalyzes the formation of the pentaglycine cross-bridge between adjacent glycan chains in peptidoglycan; directly inhibited by $\beta$-lactam antibiotics.

\beta-Lactamase

A bacterial resistance enzyme that hydrolyzes the four-membered cyclic amide ring ($\beta$-lactam ring) of penicillins, destroying the drug's antibacterial properties before it can reach penicillin-binding proteins.

mecA Gene

A mobile resistance gene carried on the Staphylococcal cassette chromosome mec (SCCmec) in MRSA that encodes PBP-2a, an altered penicillin-binding protein with low affinity for $\beta$-lactams.

Vancomycin

A large glycopeptide antibiotic ($1449.265\text{ g/mol}$) that forms a steric cap over D-alanyl-D-alanine termini on peptidoglycan pentapeptides, preventing transpeptidase access and blocking cell wall synthesis in Gram-positive bacteria.

VISA (Vancomycin Intermediate-Susceptible S. aureus)

Strains of Staphylococcus aureus with an intermediate vancomycin MIC of $4\text{ to }8\,\mu\text{g/mL}$ (first identified in Japan in 1997) that resist the antibiotic via an abnormally thickened cell wall that traps molecules before they reach the division septum.

VRSA (Vancomycin-Resistant S. aureus)

Staphylococcus aureus isolates exhibiting vancomycin MIC $\ge 16\,\mu\text{g/mL}$ (first identified in Michigan, USA in 2002) resulting from the horizontal transfer of the transposon Tn1546 from Enterococcus, which alters the peptidoglycan terminus from D-Ala-D-Ala to D-Ala-D-Lac.

vanA Operon

A five-gene cluster (vanR, vanS, vanH, vanA, vanX) located on Tn1546 where VanH converts pyruvate to D-lactate, VanA synthesizes D-Ala-D-Lac depsipeptides, and VanX hydrolyzes normal D-Ala-D-Ala, preventing vancomycin binding.

Daptomycin

A cyclic lipopeptide antibiotic derived from Streptomyces roseosporus that inserts its decanoate lipid tail into Gram-positive bacterial cell membranes in a calcium-dependent manner, inducing rapid depolarization, potassium ion efflux, and cell death without causing cell lysis.

Telavancin

A semi-synthetic lipoglycopeptide derivative of vancomycin approved for complicated skin/soft tissue infections and pneumonia that exhibits a dual mechanism: inhibition of peptidoglycan synthesis via D-Ala-D-Ala binding and disruption of bacterial cell membrane potential.

Linezolid

A synthetic bacteriostatic oxazolidinone antibiotic that binds to the 23S rRNA of the bacterial 50S ribosomal subunit at the peptidyl transferase center, preventing the assembly of the functional 70S initiation complex.

Ciprofloxacin

A broad-spectrum synthetic fluoroquinolone antibiotic that binds to and inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, trapping cleaved DNA-enzyme intermediates and blocking replication fork progression.

Colistin

A last-resort polymyxin polypeptide antibiotic derived from Paenibacillus polymyxa that binds to lipid A in the lipopolysaccharide (LPS) outer membrane of Gram-negative pathogens, displacing divalent cations ($Mg^{2+}, Ca^{2+}$) to disrupt membrane integrity.

Microbial Biofilm

A structured community of microbial cells embedded in a self-produced extracellular polymeric substance (EPS) matrix made of extracellular DNA, lipids, proteins, and exopolysaccharides, conferring high phenotypic tolerance to antimicrobials and host defenses.

Photodynamic Therapy (PDT)

A targeted medical treatment combining a non-toxic photosensitizer drug, oxygen ($O_2$), and light of a specific wavelength (typically $600\text{ to }850\text{ nm}$) to generate cytotoxic reactive oxygen species and singlet oxygen that destroy pathological cells.

Type I vs. Type II Photochemical Reactions

The two primary pathways occurring after light excites a ground-state photosensitizer ($^1\text{PS}$) to an excited triplet state ($^3\text{PS}^*$): Type I involves electron/hydrogen transfer to biomolecules or oxygen to form free radicals ($O_2^{\bullet-}, \text{OH}^{\bullet}, H_2O_2$), whereas Type II involves direct energy transfer to ground-state molecular oxygen to produce cytotoxic singlet oxygen ($^1O_2$).

5-Aminolevulinic Acid (5-ALA)

A hydrophilic pro-drug that enters the mitochondrial heme biosynthetic pathway, where porphobilinogen deaminase upregulation and ferrochelatase deficiency in tumor cells lead to the selective accumulation of the potent photosensitizer protoporphyrin IX (PpIX).

mTHPC (Foscan)

A second-generation, highly hydrophobic photosensitizer (temoporfin) approved for advanced head and neck cancers that absorbs strongly at a red wavelength of $652\text{ nm}$, enabling deep light penetration into solid tumor tissues.

Photodynamic Diagnosis (PDD)

A diagnostic and fluorescence-guided surgical technique where preferential photosensitizer accumulation (such as PpIX under blue light at approximately $405\text{ nm}$) emits visible red fluorescence ($\sim 635\text{ nm}$) to delineate tumor boundaries.

Plasmodium Lifecycle

The developmental cycle of malaria parasites alternating between the human host (sporozoite inoculation, hepatic schizogony yielding merozoites, and cyclic erythrocytic invasion) and the female Anopheles mosquito vector (gametocyte uptake, midgut fertilization into motile ookinetes, oocyst encystment, and salivary gland sporozoites).

Hypnozoite

A small, uninucleate, dormant liver stage formed by Plasmodium vivax and Plasmodium ovale that remains quiescent for weeks to months before reactivating to release merozoites into the bloodstream, causing relapsing malaria.

Chloroquine

A 4-aminoquinoline blood-stage antimalarial that diffuses into the parasite's acidic food vacuole via pH trapping and binds free heme, preventing its biocrystallization into non-toxic hemozoin and causing toxic heme accumulation.

PfCRT K76T Mutation

A point mutation in the Plasmodium falciparum chloroquine resistance transporter where positively charged lysine ($K$) is replaced by neutral threonine ($T$) at position $76$, allowing dicationic chloroquine to escape the food vacuole down its electrochemical gradient.

PfMDR1 (P-glycoprotein Homolog 1)

An ATP-binding cassette transporter located on the Plasmodium food vacuole membrane that imports solutes into the vacuole; gene amplification reduces cytosolic concentrations of arylamino alcohols (mefloquine, lumefantrine), conferring resistance.

Artemisinin

A sesquiterpene lactone antimalarial isolated from Artemisia annua that contains an endoperoxide bridge ($O\text{--}O$) cleaved by intra-erythrocytic ferrous iron ($Fe^{2+}$), producing carbon-centered free radicals that damage parasite proteins and membranes.

Artemisinin-Based Combination Therapy (ACT)

The standard frontline treatment regimen for uncomplicated Plasmodium falciparum malaria that pairs a fast-acting artemisinin derivative with a longer-acting partner drug (e.g., lumefantrine, piperaquine, or amodiaquine) to clear bulk parasites and prevent recrudescence.

Primaquine

An 8-aminoquinoline prodrug metabolized by hepatic CYP2D6 into reactive quinone intermediates that generate reactive oxygen species to eliminate dormant liver-stage hypnozoites of Plasmodium vivax and Plasmodium ovale, as well as mature stage V gametocytes.

Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency

An X-linked genetic enzyme deficiency that limits NADPH generation in red blood cells, impairing glutathione reduction and predisposing patients to severe acute hemolytic anemia when exposed to oxidative drugs like primaquine.

Cipargamin (KAE609)

An emerging spiroindolone antimalarial in phase II clinical development that inhibits the parasite plasma membrane sodium pump PfATP4, disrupting sodium homeostasis and causing rapid swelling and osmotic lysis of asexual blood stages.

Fungal Cell Wall Architecture

A specialized multilayered protective structure composed of an inner skeletal matrix of chitin and $\beta$-(1,3)$-glucan linked to$\beta$-(1,6)$-glucan, anchored beneath an outer protective coat of mannoproteins and mannans.

Azoles

A major class of synthetic agents comprising imidazoles and triazoles that inhibit lanosterol 14-$\alpha$-demethylase (encoded by ERG11), preventing ergosterol biosynthesis and accumulating toxic 14-$\alpha$-methyl sterols that disrupt membrane function.

Target-Site Azole Resistance

An acquired mechanism of drug failure caused by point mutations in the ERG11 gene that reduce drug-binding affinity, or by ERG11 promoter upregulation and gene duplication that markedly increase target enzyme levels.

Efflux-Mediated Antifungal Resistance

An active cellular defense mechanism driven by transcriptional upregulation of ATP-binding cassette (ABC) transporters or major facilitator superfamily (MFS) pumps, actively expelling therapeutic compounds from the fungal cytoplasm.

Polyenes

Fungicidal macrolide antibiotics (such as amphotericin B and nystatin) that bind membrane ergosterol and assemble into transmembrane barrel pores, causing rapid ion leakage and osmotic cell lysis.

AM-2-19

A rationally re-engineered amphotericin B derivative that extracts ergosterol into an extracellular sponge complex without forming membrane-spanning pores, eliminating host nephrotoxicity while retaining potent fungicidal efficacy.

Polyene Resistance Mechanisms

A rare form of antifungal insensitivity typically caused by loss-of-function mutations in ERG3, leading to altered membrane sterol composition, or by significant cell wall thickening with increased $\beta$-(1,3)$$-glucan content that sequesters drug molecules.

Echinocandins

A frontline class of lipopeptides (including caspofungin, micafungin, and anidulafungin) that non-competitively inhibit transmembrane $\beta$-(1,3)$$-D-glucan synthase, disrupting cell wall integrity and triggering osmotic lysis in yeasts.

FKS Gene Mutations

Specific amino acid substitutions occurring within conserved hot-spot regions of FKS1 or FKS2 (encoding the catalytic subunits of $\beta$-(1,3)$$-glucan synthase) that impair lipopeptide binding and confer clinical drug resistance.

Flucytosine (5-FC)

A fluorinated pyrimidine antimetabolite prodrug imported via cytosine permease and deaminated into 5-fluorouracil, which incorporates into RNA and inhibits thymidylate synthase to arrest fungal macromolecular synthesis.

Agricultural Triazole Dual-Use

The widespread environmental application of crop-protecting triazole fungicides sharing structural similarity with clinical agents, driving persistent selective pressure and generating cross-resistant airborne fungal strains that infect humans.

Thermotolerance Adaptation in Fungi

The environmental adaptation mechanism driven by rising global temperatures, selecting for fungal species capable of thriving at human body temperature ($37\,^\circ\text{C}$ / $98.6\,^\circ\text{F}$) and broadening the host range of opportunistic pathogens.

Candida auris

An emerging multidrug-resistant yeast classified as an urgent public health threat due to its high propensity for nosocomial transmission, persistence on inanimate clinical surfaces, and frequent pan-resistance across major antifungal classes.