Hormones and Cancer

Hormones and Cancer Course Overview

  • Instructor: Maria Mudryj, Ph.D.
  • Department: Medical Microbiology and Immunology
  • Semester: Fall 2025

Course Description

  • Focus: This undergraduate course is centered on hormones and their role in cancer development.
  • Format:
    • Classes held two days per week.
    •  Day 1: Introduction to hormones, cancer, and specific hormone-driven cancers.
    •  Day 2: Discussion-based analysis of a research paper relevant to the weekly topic.
  • Participation:
    • Students are required to read the assigned paper and engage in discussions which will include critical evaluation of the paper and methodologies.
  • Assessment:
    • Weekly quizzes (15 minutes each) consisting of approximately 3 questions on the previous week's content (90% of final grade).
    • Class presentations (10% of final grade).

Introduction to Hormones

Definition of a Hormone

  • Coined by Earnest Starling in 1905, derived from Greek meaning "to arouse or excite."
  • Defined as chemical messengers that travel through the bloodstream coordinating activities and growth among different body parts.
  • Hormones act by being secreted from one area of the body and traveling to target cells or organs.

The Endocrine System

Major Glands and Hormones Produced

  • Hypothalamus:
    • Releases TRH, CRH, GHRH.
  • Pineal Gland:
    • Produces Melatonin.
  • Pituitary Gland:
    • Hormones: GH, TSH, ACTH, FSH, MSH, LH, Prolactin, Oxytocin, Vasopressin.
  • Adrenal Glands:
    • Hormones: Androgens, Glucocorticoids, Adrenaline, Noradrenaline.
  • Thyroid and Parathyroid Glands:
    • Hormones: T3, T4, Calcitonin, PTH.
  • Pancreas:
    • Hormones: Insulin, Glucagon, Somatostatin.
  • Ovaries/Placenta:
    • Hormones: Estrogens, Progesterone.
  • Testes:
    • Hormones: Androgens, Estradiol, Inhibin.
  • Other organs:
    • Liver, Thymus, Stomach, Kidney, Uterus

Classes of Hormones

Peptide Hormones

  • Examples include Insulin, Glucagon, Prolactin, ACTH, Gastrin, Parathyroid hormone.
  • Synthesis:
    • Created as prohormones needing further processing (cleavage) to become active.
  • Storage:
    • Stored in vesicles for regulated secretion.
  • Solubility:
    • Most are polar and water-soluble, enabling free travel in blood.
  • Receptor Interaction:
    • Bind to cell membrane receptors and use second messenger systems for signal transduction.
  • Effects:
    • Often induce fast, transient changes in protein activity, occasionally leading to gene expression modifications.

Steroid Hormones

  • Examples: Cortisol, Aldosterone, Estrogen, Progesterone, Testosterone.
  • Synthesis:
    • Formed through a series of biochemical reactions from cholesterol.
  • Storage:
    • Released immediately following synthesis (constitutive secretion).
  • Solubility:
    • Generally non-polar; necessitate carrier proteins in blood.
  • Receptor Interaction:
    • Bind to intracellular receptors affecting gene expression directly.
  • Effects:
    • Changes in gene expression occur more slowly but last longer than peptide hormones.

Amino Acid-Derived Hormones

  • Examples: Adrenaline (Epinephrine), Thyroxin, Triiodothyronine.
  • Synthesis:
    • Derived from amino acid tyrosine.
  • Storage:
    • Storage mechanism varies.
  • Solubility and Action:
    • Some amino acid derivatives (e.g., adrenaline) are polar; others require protein binding.
    • Adrenaline interacts with membrane receptors, while thyroid hormones interact with nuclear receptors.
  • Effects:
    • Adrenaline behaves similarly to peptide hormones; thyroid hormones function like steroids.

Peptide Hormones - Insulin Example

  1. Insulin Gene Structure:
    • Contains multiple exons leading to the production of the functional insulin protein.
  2. Synthesis Steps:
    • Preproinsulin → Proinsulin → Mature Insulin comprising A-Chains and B-Chains.
  3. Function:
    • Facilitates glucose uptake in target cells via signaling pathways.

Adrenaline Signaling Effects

  • Accelerates heart and lung function.
  • Inhibits digestive processes.
  • Constricts blood vessels while liberating energy sources for muscle function.
  • Affects multiple bodily functions, including pupil dilation and bladder relaxation.

Mechanisms of Action for Steroid Hormones

  • Steroids enter cells and bind to nuclear receptors, resulting in transcriptional modulation of target genes.
  • Nuclear Receptor Superfamily:
    • Comprises various subfamilies affecting gene regulation upon activation by ligands.
  • Examples of steroid hormones affecting cancer include Estrogen, Progesterone, Testosterone, etc.

Conclusion

  • Recap of major topics discussed: hormonal definitions, synthesis pathways, cellular actions, and implications in cancer.
  • Emphasis on the importance of understanding hormone interaction in the context of cancer biology.