Stem Cell (5-7)

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Questions and Answers

What role do free radicals play in the context of cancerous growth?

They have no impact on cellular functions.

They can break DNA strands, leading to gene alteration. (correct)

They restore DNA integrity through oxidative stress.

They enhance cellular growth processes.

Which factor does NOT contribute to the buildup of free radicals in the body?

Chronic malnutrition

Excessive calorie intake

Exposure to sunlight (correct)

Extreme exercise

Which nutrients have been shown to potentially increase the number of DNA repair enzymes?

Omega-3 and Vitamin E

Calcium and Vitamin D

L-carnitine, zinc, and the B-vitamins (correct)

Vitamin C and magnesium

What is a primary effect of oxidative stress caused by free radicals?

Decreased DNA integrity Signup and view all the answers

What significant association has been observed in relation to cancer and free radical production?

High oxidative stress relates to cigarette smoking. Signup and view all the answers

Which process can help optimize the body's ability to heal DNA?

Consuming antioxidants Signup and view all the answers

What is the primary characteristic of a free radical?

It lacks an electron. Signup and view all the answers

Which statement is true regarding the relationship between oxidative stress and cancer?

Oxidative stress can lead to permanent gene activation. Signup and view all the answers

What role do cancer stem cells play in cancer development?

Initiate, progress, metastasize, and recur cancer Signup and view all the answers

Why are traditional therapies like chemotherapy and radiotherapy often ineffective against cancer stem cells?

Standard therapies target only differentiated cancer cells Signup and view all the answers

Which biological process enables cancer stem cells to evade immune responses?

Epithelial to mesenchymal transition (EMT) Signup and view all the answers

What characteristic of cancer stem cells contributes to their drug resistance?

Increased DNA repair activity Signup and view all the answers

What are the primary components found in stem cells that contribute to skin rejuvenation?

Amino acids and Peptides Signup and view all the answers

Which type of stem cells are most commonly used in skin care products?

Plant stem cell extracts Signup and view all the answers

Which of the following statements regarding cancer stem cells is incorrect?

They are responsible for the initial DNA damage. Signup and view all the answers

What is a significant misconception about stem cell skin care products?

They help build new skin cells. Signup and view all the answers

What effect do excessive free radicals have related to cancer?

Lead to DNA damage that can initiate cancer Signup and view all the answers

Which feature of cancer stem cells helps them adapt during treatment?

Adaptation to scarce nutrient conditions Signup and view all the answers

What benefit do plant stem cell extracts provide to the skin?

They nourish skin cells and promote cell turnover. Signup and view all the answers

Why do dermatologists prefer plant-based stem cells over animal sources?

They reduce the risk of transmitting diseases. Signup and view all the answers

What is a common characteristic of both normal stem cells and cancer stem cells?

Capability for self-renewal and differentiation Signup and view all the answers

What potential outcome might result from using products containing stem cells?

Improved skin texture and tone. Signup and view all the answers

What is a characteristic of stem cells that makes them beneficial for skin care?

They provide growth factors for skin repair. Signup and view all the answers

What common feature do both animal and plant stem cells share in skin care applications?

They possess antioxidant properties. Signup and view all the answers

What is one goal of regenerative medicine?

To exploit exogenous or endogenous stem cells Signup and view all the answers

What is a significant challenge faced in stem cell therapies?

Unanticipated challenges in safety or efficacy Signup and view all the answers

In the context of plant cells, which of the following statements is true?

Plant cells can be cultivated in murashige and skoog medium. Signup and view all the answers

What can stem cells potentially contribute to, aside from tissue replacement therapies?

Facilitating classical drug development Signup and view all the answers

What are exosomes commonly associated with in cellular biology?

Involved in intercellular communication Signup and view all the answers

What is the ultimate purpose of replacing tissues with stem cells for diseases caused by gene mutations?

To correct the genetic defect Signup and view all the answers

What is a characteristic of pluripotent human stem cells in therapy?

They present technical hurdles to therapy. Signup and view all the answers

What is a misconception about stem cells in the context of classical drug development?

Stem cells are irrelevant to drug development. Signup and view all the answers

Which of the following stem cells are derived from adult tissues?

Bone Marrow Stem Cells Signup and view all the answers

What is a requirement for allogeneic stem cell transplants?

Patients must take immunosuppressive drugs. Signup and view all the answers

What process involves injecting an adult somatic cell nucleus into an enucleated oocyte?

Somatic Cell Nuclear Transfer (SCNT) Signup and view all the answers

Which stem cells are specifically mentioned as sources for potential therapies in the liver and pancreas?

Liver Stem Cells and Pancreatic Stem Cells Signup and view all the answers

What is the primary goal of tissue engineering?

To produce biological substitutes that restore or improve tissue function. Signup and view all the answers

Which of the following sources is rarely used for obtaining adult stem cells?

Wharton’s Jelly Signup and view all the answers

What is a characteristic feature of patient-specific stem cell therapies?

They often require genetically equivalent cells. Signup and view all the answers

What does tissue engineering utilize to impact biological functions?

Cells, engineering principles, and appropriate biochemical factors. Signup and view all the answers

Study Notes

Cancer Stem Cells (CSCs)

Stem cells are vital for regenerating and repairing organs like the heart, lungs, skin, germ cells, and other tissues.
Cancer stem cells (CSCs) are responsible for cancer initiation, progression, metastasis, recurrence, and drug resistance.
In 2020, approximately 19 million new cancer cases and 10 million deaths were reported.
CSCs are a small subpopulation of tumor cells with self-renewal, dedifferentiation, tumorogenicity, and inherent chemo-and radiotherapy resistance.
CSCs cause tumor relapse and failure of conventional therapies.
CSCs originate from somatic stem cells, adult progenitor cells, and adult somatic cells.
CSC features include self-renewal, diverse progeny, and immortality.
Telomerase activity in CSCs is high, contributing to their immortality.
The CSC hypothesis proposes that CSCs are quiescent (tumorigenic) and resistant to chemotherapy, leading to the formation of new tumors.
Normal cells are small, uniformly shaped, have a relatively large volume, conform to cell size and shape, and cells within the tissue are arranged into discrete tissues.
Normal cells are able to differentiate, have a normal presentation of cell surface markers, which have lower levels of dividing cells, and have clearly demarcated tissue compartments.
Cancer cells are large, have variable shaped nuclei, and relatively small cytoplasmic volume.
Cancer cells can vary in cell size and shape, with disorganised cells arrangements and a loss of normal specialized features.
Cancer cells have elevated expression of certain cell markers. Large numbers of dividing cells and poorly defined tumor boundaries are further common characteristics of cancer cells than normal cells.
Cancer is preceded by damaged DNA that alter cell processes including those that regulate growth and division.
Free radicals in the body take electrons from structures which can lack an electron, causing oxidative stress.
Free radicals can build up from radiation, chemicals, chronic malnutrition, excessive intake of calories, or extreme exercise.
High amounts of oxidative stress are associated with high rates of cancer.
Optimizing DNA repair enzymes, such as by using antioxidants, is important.
Stem cells do not divide rapidly, therefore conventional chemotherapy targeting rapidly dividing cells does not target stem cells.

Exosomes

Extracellular vesicles (EVs) are membrane-derived nano-meter-sized vesicles.
Normal, diseased, and transformed cells release EVs in vitro and in vivo.
Exosomes contain lipids, proteins, mRNAs, non-coding RNAs, and DNA.
Exosomes can be generated intracellularly from multi-vesicular bodies (MVBs).
Exosomes are produced by budding from the extracellular membrane.
Apoptotic vesicles are released upon cell fragmentation.
Exosomes can be used in diagnostics, immunotherapy, and combating diseases and pathological situations like senescent aging, cancer, and arthritis.
Exosomes can act as a targeted drug delivery vehicle and potentially treat diseases, e.g. Alzheimer's disease and Parkinson's disease.
Exosomes are small in size (~30-150 nm), have complex properties, and are stable during storage.
Compared to stem cell therapies, exosomes do not present issues in tumor formation.

Stem Cell Banking

A stem cell bank collects and stores human stem cells for various uses.
Public and private banks exist, with donors needing similar HLA types for transplantation to avoid rejection.
Donor selection considers completely matched siblings as the ideal match, with partially matched donors acceptable if no exact match is available.
Race/ethnicity also play role in donor recruitment.
Cryopreservation techniques, such as using freeze-drying and spray-drying, are implemented to preserve stem cells for long periods.

Tissue Engineering

Tissue engineering utilizes interdisciplinary fields' principles in engineering, materials, and biochemistry to restore, maintain, or improve biological functions.
The goal of regenerative medicine is to exploit these cells either by transplanting them from an exogenous source or by activating endogenous stem cells pharmacologically.
Tissue engineering involves the use of scaffolds (biocompatible), in vitro culture, and tissue implantation to generate functional tissues and organs.
Potential applications include creating artificial tissues (bladders), organs, and even entire body parts like hearts.
Advantages of tissue engineering include eliminating transplant rejection, saving lives, improving lives, and potentially eliminating many surgeries for treating illnesses.
Disadvantages are difficulties in designing scaffolds, necessary research and understanding of cadaver organs and tissues, cells need to stay alive inside body and continue to functioning and ethical concerns.

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