Nanoparticles Applications in Cancer Therapy and

Diagnosis

By: M. Shafiee

PhD student, Biochemistry Department, Shiraz

University of Medical Sciences, November 2008.

Nanotechnology• 1st trigger: by the Nobel Laureate, R. Feynman in

1959:

“Using larger machines to manufacture smaller ones”

• N. Taniguchi, 1974: used the term “nano”, meaning “dwarf”.

• The principle: engineering and manufacturing of systems or device at the molecular level.

Nanotechnology (cont…)

Nanotechnology (cont...)• Understanding and control of matter at

dimensions of 1 to 100 nanometer, sometimes up to 500 nm.

• Multidisciplinary, using bio-nonomaterials in engineering or engineered nanomaterials in biology and medicine.

• Different aspects:• Nanomaterials • Nanodevices• Nanosystems

Nanoparticles in medicine

Using nanoscale-sized structures for:

• Treatment (drug/gene delivery, etc.)

• Diagnosis and screening

• Tissue engineering

Basic concepts of NPs

• Bulk properties of materials in nano-sized structure differ significantly from the original material.

• Altering the size of building blocks can controle internal and surface chemistry, electrical conductivity, magnetic properties etc…

NPs and Cancer

• Apply the interaction of NPs with cellular and molecular components for:

1-Cancer diagnosis

2-Cancer therapy: a. Systemic administration

b. Local administration

Targeting to Cancer

• Targeting to neovasculature

• Targeting to cancer cells:

1- Passive targeting

2- Active targeting

Passive targeting• Is related to different characteristics of

neoplasm tissue:

1-Open gaps through interendothelial channels.

2-Less lymphatic drainage.

• NPs Cause enhanced permeability and retention effect (EPR).

• So in the reticuloendothelial system (RES) the uptake should be avoided.

Active targeting

• By specific interactions:

Antigen-antibody

Ligand-receptors

• Targeted to:

Angiogenesis

Tumor vasculature

Cancer cells specific antigen

Common targets in Active targeting

• VEGF receptors.

• Integrins, e.g. αvβ3 by NPs with RGD.

• Folate receptor (overexpressed in various epithelial cancer cells).

• EGF receptor.

• Specific tumor Ag, such as PSA.

• Surface carbohydrates, using lectins.

Various types of NPs• From last 2 decades:

Gelatin, Ceramic, Liposomes, Micelles

• More recently:

Conventional polymeric NPs

Long-circulating polymeric NPs

Quantum Dots (QDs)

Dendrimers

Aptamers

Metallic and Magnetic NPs

Conventional polymeric NPs

Conventional polymeric NPs for passive drug delivery

• Incorporation of drugs to polymers.

e.g PIHCA [poly(isohexylcyanoacrylate] with

doxorubicin.

Hydrophobicity causes the uptake by liver,

spleen and lung and higher conc. in these

organs in compare with free doxorubicin.

Conventional polymeric NPs advantages

• Hepatocarcinomas and metastasis to liver.

Drug accumulation in Kupffer cells’ lysosomes makes a reservoir for gradient and gradual release.

• Treatment of some lymphomas.

Conventional polymeric NPs disadvantages

• By targeting the BM cause myelosuppressive effects.

• Renal toxicity due to mesengial cells uptake and glomerolar damage.

• Cardiotoxicity.

• Short circulating time due to uptake by RES.

Long-circulating NPs

Hydrophilic coat

Modifications in long-circulating polymeric NPs

Long-circulating NPs• “Stealth” particles invisible to macrophages.

• Directly target tumors outside of MPS.

• Modifications: Size < 100 nm

Hydrophilic Surface

• Repel plasma proteins and prevent opsonization.

• Improving circulation time.

• More extravasation and retention.

Long-circ. NPs (cont…)

• A dynamic cloud of hydrophilic chains is made by:

1-Adsorption of surfactants.

e.g. Poloxamine, Polysorbate 80

2-Use of block or branched polymers.

e.g. polyethylene glycol (PEG) and Pluronic.

Schematic of enhanced permeability and retention effect.

Quantum Dots

QDs

Quantum Dots

• Nanocrystals composed of a core of a

semiconductor material (CdSe), enclosed within

a shell of another semiconductor (ZnS) that has

a larger spectral band gap.

Spectral band gap: the separation between electronic energy

levels of a material.

QDs characteristics

• Diameter of about 2–10 nm, allows one-on-one

interaction with biomolecules such as proteins.

• Inorganic fluorophores that have size-tunable

emission.

• Strong light absorbance.

• Bright fluorescence.

• High photostability.

QDs’ applications

• Imaging and detection

• Therapy

Multicolor quantum dot (QD) capability of QD imaging in live animal, using 3 different QDs with the same wavelength in deep organs.

specific mAb attachment to the QD

QDs for imaging and diagnosis

• QDs emit in the IR and near-IR regions, imaging

and diagnostic of cells deep within tissues.

• Long-term and real time imaging due to stability.

• mAb conjugated QDs to detect specific tumor Ags

and tumor site detection.

Schematic concept of single-QD-based DNA probe. FRET= Fluorescence resonance energy transfer

Emission (QD)605 nm

Excitation488 nm

Emission Cy5670 nm

FRET

)C (Fluorescent images of QDs (top), Cy5 (middle) and merged colors (bottom) with complementary DNA target and (D) non-complementary DNA target.

Dendrimers

Generations in a dendrimer

Dendrimers

• The Greek word dendron, meaning "tree".

• Repeatedly branched, monodisperse, and usually highly symmetric globular compounds.

• The branching units are described by generation.

• Characterized by their terminal generation, e.g. a G5 dendrimer refers to a polymer with four generations.

Dendrimers

(1) PAMAM. (polyamidoamine dendrimer).(3) Bow tie dendrimer based on 2,2-bis(hydroxymethyl) propionic acid.

Interaction of PAMAM dendrimers with lipid bilayers.

Dendrimers’ pharmacokinetics

• Can be tuned by varying generation size and the rate of PEGylation, esp. in bow tie forms.

Drug delivery by dendrimers

• Non-covalent encapsulation in the interior of the dendrimer.

• Covalently conjugation to form macromolecular prodrugs.

Dendrimer-drug conjugates

• Antineoplastic agent covalently attached to the peripheral groups of the dendrimer.

e.g. carboxylate-terminated G3 PAMAM conjugated with MTX, is 24-fold more effective than free MTX on MTX resistant cell lines.

Dendrimers for targeted drug delivery and imaging

A G5-PAMAM conjugated anti-HER2 mAb targets tumors that overexpress HER2.

Drug

Dendrimers for photothermal therapy

• Gold-based NPs strongly absorb light in the near-IR region.

• Facilitating deep optical penetration into tissues.

• Generating a localized lethal dose of heat at the site of a tumor.

• Only within the last year (2007), dendrimer-encapsulated gold nanoparticles prepared and identified for the photothermal treatment of malignant tissue.

Photothermal therapy

Photothermal therapy using dendrimer-entrapped gold nano-particles.

Aptamers

Aptamers

• The Latin word “aptus”, means “to fit.”

• Single-stranded DNA, RNA, or unnatural oligonucleotides that fold into unique structures capable of binding to specific targets with high affinity and specificity.

• Unlike anti-sense oligonucleotides (siRNA), bind and inhibit different types of targets directly.

Aptamers’ advantages

• Small size (~5 nm for 30–60 base pair of aptamer).

• Highly stable in wide range of temperature and pH (~4-9).

• No batch-to-batch variations in compare with mAbs.

Aptamers production

• SELEX

“ Systematic evolution of ligands by exponential enrichment”

• A selection and amplification protocol to isolate single-stranded nucleic acid ligands that bind to their target with high affinity and specificity.

Aptamer–NP conjugates

Long-circ. NP

Aptamer–NP conjugates for targeted cancer therapy and diagnosis

• Conjugation to drug encapsulated NPs.

• Binding to optical imaging agents including:

Fluorophores

QDs (nanocrystals)

MRI imaging agents such as magnetic nanoparticles.

Aptamer-drug conjugates for targeted drug delivery

PSA aptamer

Doxorubicin

Interaction

Physical conjugate

+

Conclusion

• NP-based therapeutics for clinical use:

1. Approved for clinical use.

e.g. PEGylated NPs such as PEG-anti VEGF aptamer

2. In clinical trial period.

e.g. Pluronic block-copolymer doxorubicin, in phase II

3. In preclinical development period.

e.g. foliate-PAMAM dendrimers

• Main references: 1. Lisa Brannon-Peppas, James O. Blanchette, Nanoparticle and

targeted systems for cancer therapy, Advanced Drug Delivery Reviews 56 (2004) 1649– 1659.

2. Jesse B. Wolinsky, Mark W. Grinstaff, Therapeutic and diagnostic applications of dendrimers for cancer treatment, Advanced Drug Delivery Reviews 60 (2008) 1037–1055.

3. Hassan M.E. Azzazy , Mai M.H. Mansour , Steven C. Kazmierczak, From diagnostics to therapy: Prospects of quantum dots, Clinical Biochemistry 40 (2007) 917–927.

4. Omid C. Farokhzad, Sangyong Jon, and Robert Langer, Aptamers and Cancer Nanotechnology, 2006 by Taylor & Francis Group, LLC, pp 289-306.

5. Tania Betancourt, Amber Doiron,and Lisa Brannon-Peppas, Polymeric Nanoparticles for Tumor-Targeted Drug Delivery, 2006 by Taylor & Francis Group, LLC, pp 215-226.

• Main references (cont…): 6. Sushma Kommareddy, Dinesh B. Shenoy, and Mansoor M. Amiji,

Long-Circulating Polymeric Nanoparticles for Drug and Gene Delivery to Tumors, 2006 by Taylor & Francis Group, LLC, pp 231-239.

7. Hassan M.E. Azzazy , Mai M.H. Mansour , Steven C. Kazmierczak, From diagnostics to therapy: Prospects of quantum dots, Clinical Biochemistry 40 (2007) 917–927.

8. Noritada KAJI, Manabu TOKESHI, and Yoshinobu BABA, Quantum Dots for Single Bio-Molecule Imaging, ANALYTICAL SCIENCES JANUARY 2007, VOL. 23, pp 21-24.

9. Lisa Brannon-Peppas, James O. Blanchette, Nanoparticle and targeted systems for cancer therapy, Advanced Drug Delivery Reviews 56 (2004) 1649– 1659.

Thank You