NAVEENA GIRISH DEPARTMENT OF PLANT SCIENCE

CENTRAL UNIVERSITY OF

KERALA

CAN YOU GIVE DEFINITIONS FOR FOLLOWING TERMS?

• CANCER?

• BENIGN AND MALIGNANT TUMOURS ?

• METASTASIS?

• CARCINOMA?

• SARCOMA?

• LEUKEMIA?

• CARCINOGENS?

• A tumor that is not capable of indefinite growth and does

not invade the healthy surrounding tissue extensively is benign.

• A tumor that continues to grow and becomes progressively invasive is malignant

• small clusters of cancerous cells dislodge from a tumor, invade the blood or lymphatic vessels, and are carried to other tissues, where they continue to proliferate. – metastasis

• carcinomas, tumors that arise from endodermal or ectodermal tissues such as skin or the epithelial lining of internal organs and glands

• sarcoma derived from mesodermal connective tissues such as bone and cartilage.

• Leukemia – abnormal proliferation of WBC

• Lymphoma tumors comes on spleen and lymph node

Malignant transformation of cells

• Normal cell in vitro transformed cells

Initiation& promotion is the steps in cancer development

Physical &chemical agents

These cells requires low anchorage dependence, decreased dependence of

growth factors ,and grow in density independent fashion like cancer cells

Malignant transformation can also be happens by viruses, its genome integrate to host DNA, oncogene in virus induce cancer

e.g. . Rous sarcoma virus v-src gene is responsible for cancer

Oncogenes (both viral and cellular) are derived from cellular genes that encode various growth-controlling proteins – Howard Temin

the conversion of a proto-oncogene into an oncogene appears in many cases to accompany a change in the level of expression of a normal growth controlling protein.

Oncogenes and cancer induction

• Cellular proliferation/ cell death

Imbalance

cancer

Balance is maintained by oncogenes and

tumor suppressor gene

Inappropriate expression of either a growth factor or its receptor can result

in uncontrolled proliferation

Proto oncogene to oncogene

AMPLIFICATIONTRANLOCATION

&INSERTION BY

VIRUS

ONCOGENE ACTIVATION

Tumors of immune system

• Solid tumor on bone marrow lymph nodes and thymus

• Include hodkins & non hodkins lymphoma

Lymphoma

• Proliferate as single cell

• Increased cell no. in blood or lymph

• Classified as acute and chronicLeukemia

Leukemia

CHRONIC

chronic

lymphocytic leukemia (CLL))

chronic myelogenous

leukemia (CML

ACUTE

Acute lymphocytic

leukemia (ALL));

Acute myelogenous

leukemia (AML

CHRONIC ACUTE

The chronic leukemia were much less aggressivedeveloped slowly as mild, barely symptomatic diseases.

The acute leukemia's appeared suddenly and progressedrapidly

Tend to arise in less mature cells, Arise in mature cells.

TUMOR ANTIGENSTSTA & TATA

• Tumor-specific antigens are unique to tumor cells and do not occur on normal cells in the body.

• Mutation creates new peptide - processing of it –MHCI presents it - Tcyt try to kill it

• Tumor-associated antigens are not unique to tumor cells and occur on also in normal cells in the body

Tumor antigens-4 categories

■ Antigens encoded by genes exclusively expressed by tumors

■ Antigens encoded by variant forms of normal genes that have been altered by mutation

■ Antigens normally expressed only at certain stages of differentiation or only by certain differentiation lineages

■ Antigens that are over expressed in particular tumors

Procedure for identifying genes encoding TSTA

THESE MUTANT TUMORS CELLS ARE DESIGNATED AS tum- VARIANTS

SOME CELLS ARE MUTATED AND ARE INCAPABLE OF GROWING IN TO A TUMOR IN SYNGENIC MICE

MOUSE TUMORIGENIC CELL LINE(tum+), GIVING RISE TO PROGRESSIVELYGROWING TUMORS & TREATED IN VITRO WITH A CHEMICAL

MUTAGEN

The TSTA specific CTLs destroy tum- tumor cells preventing tumor growth

When this variant cells are injected to a syngenic mice , the unique TSTA are recognized by specific CTLS

Most of this variants have been shown to TSTA not expressed by original TSTA variants

CHARECTERISATION OF TSTA –2 METHODS

SEQUENCE ANALYSED THROUGH EDMANN DEGRADATION

MHC + PEPTIDE

Virally induced tumor antigen

In contrast to chemically induced tumors , virally induced tumor express tumor antigens shared by all tumors induced by the same virus

TATA

• It is expressed on fetal and tumor cells not in normal cells – oncofetal tumor antigens

• E.g. Alpha-fetoprotein (AFP) found in liver cancer cells and fetal cells as milligram and nanogram in normal cells

• Carcinoembryonic antigen (CEA). – colorectal cancer cells

• the presence of these oncofetal antigens is not diagnostic of tumors but rather serves to monitor tumor growth.

( a patient has had surgery to remove a colorectal carcinoma,CEA levels are monitored after surgery. An increase in the CEA level is an indication of resumed tumor growth.)

Oncogene proteins as tumor antigens

• human breast-cancer cells exhibit elevated expression of the oncogene-encoded Neuprotein, a growthfactor receptor, whereas normal adult cells express only trace amounts of Neu protein

TATAs on human melanoma

Oncofetal - MAGE 1 , MAGE 3, BAGE, GAGE 1 , GAGE 2ONCOGENE PROTEINS –MART 1, gp75, gp 100,Melan A

WAR BETWEEN CANCER CELL & IMMUNE CELL

?

WHAT WILL EACH OF THESE CELLS DO TO GET SUCCESS IN THIS WAR?

CANCER CELL

• MHC EXPRESSION DECRESES

• ANTIGENIC MODULATION

• COSTIMULATORY SIGNALS DECRESES

• ANTIBODY MASKING

IMMUNE CELL

DETECTION

• BY MHC I EXPRESSION

• LIPID ASSYMMETRY

KILLING

• MACROPHAGES, KILLER (NK AND TC )

SIGNALLING

Immune response to tumors

• T cell mediated immunity

Tcyt provide effective anti tumor immunity together with

class I MHC molecules

The stimulation of TH cells activate Tcyt cells , once

activated then again co stimulation is not

needed• T H cell recognize tumor Tcyt cell destruct tumor

• CD40 on T cell amplify immune response, cytokines call

macrophages , dendritic cells

IMMUNE SURVIELLANCE THEORY – WHEN TUMOR CELLS ARISE CELLS OF THE BODY RECOGNISE THEN & ELIMINATE1900 , PAUL EHRLICH

• Cross priming / cross presentation

BY M.J BEVAN

THE ABILITY OF APC TO PRESENT ANTIGEN BY CLASSI MHC PATHWAY IS CALLED CROSS PRESENTATION

NK CELL & MACROPHAGE MEDIATED IMMUNITY

• NK cell – missing self hypothesis –it is not MHC restricted so it can detect & kill tumor cells that escape from Tcyt cells

• Antibody-Dependent Cell-Mediate Cytotoxicity (ADCC) is linked with NK cells

• NK cell Activity increases in presence of IL 2 (adoptive immunotherapy – LAK)

• CHEDIAK HIGASHI SYNDROME -

CANCERNK

• MACROPHAGE• NON MHC MEDIATED

• ADCC – WITH ANTIBODY

• DEGRADATION OF TUMOR IS DUE TO LYTIC ENZYMES & ROS

• TNF (TUMOR NECROSIS FACTOR)

INDUCES NECROSIS OF TUMOR , BY THROMBOSIS IN BLOOD VESSELS

RESULTING IN ISCHAEMATIC DEGRADATION OF TUMOR OR DIRECT APOPTOSIS

EVATION OF IMMUNE RESPONSE BY TUMOR (TUMOR ESCAPE)

DOWN REGULATION CLASS I MHC MOLECULES

ADENO VIRUS – INHIBITTRANSCRIPTION OF CLASS I MHCHERPES SIMPLEX VIRUS – TAP INHIBITES

MODULATION OF TUMOR ANTIGEN

• IN PRESENCE OF SERUM ANTIBODY ANTIGEN DISAPPEARS

• ANTIGEN LOSS VARIANTS FORMED

• OBSERVED IN MICE WITH T CELL LEUKEMIA –TL ANTIGEN IS MODULATED IN PRESENCE OF ANTI TL ANTIBODY

LACK OF COSTIMULATORS LIKE B7 ON APC- CD28 ON T CELL NEEDED TCELL GET PARTIAL SIGNAL , it

is another reason

Antigen masking

Coating antigen with glycocalyx or fibrin

Tumor cells produce more glycocalyx (surfce carbohydate )

Sialic acid

Blocking of Tcyt response by antibodies

• Antibodies formed against a tumor bearing host may bind to tumor antigens effectively blocking epitopes from Tcyt cells

• Mediated by antibodies alone or by antigen antibody complex

• These complexes may bind with with NK cells or macrophages and inhibit ADCC

SUPPESSION OF ANTI TUMOR IMMUNE RESPONSES

• Transforming growth factor β inhibit effectorfunctions of NK , macrophages

• Fas ligand bind fas molecule on leukocytes –apoptotic death of leukocytes

Preventing inflammatory response by secreting IL 10, VEGF - dendritic cell inactivated

Cancer immunotherapy/ biologic therapy

Uses hosts own immune system to fight against cancer and its side effects

Active

• Host immunity should not significantly weakened

Passive

• Tumor specific antibodies and Tcyt administrated

Active immunotherapy

• Killed tumor cell to patient enhances his immunity by increasing T cell population increase

• Patient specific tumor antigens used

• MAGE , mutated p53 common tumor antigens – broad spectrum of activity

RECENT RESEARCH FINDINGSMHC- PEPTIDECOMPLEX EXTRACTED &TESTED WHICH PEPTIDE CREATES

MORE T CELL ACTIVATION

ANTIGEN INTRODUCTION IS THROUGH RECOMBINANT VIRAL OR

BACTERIAL AGENTS( STUDIED ON FELINE LEUKEMIA IN RATS & HERPES

LYMPHOMA IN CHICKS)

ANOTHER METHOD IS EXTRACT APC & INTEGRATE TUMOR ANTIGEN GENE INTO IT AND INTRODUCE

BACKTO HOST

• AUGMENTATION OF IMMUNE RESPONSE BY COSTIMULATORS AND CYTOKINES ETC TO INDUCE T CELLS PROLIFERATION

• COSTIMULATORS WAS STUDIED IN MICE TUMOR CELL INTEGRATING WITH B7 GENE–Tcyt ACTIVATED

• LIKE THIS GENES OF CYTOKINES IL2 IL4 GM-CSF

• SYSTEMIC CYTOKINE THERAPY – INJECTION OF PURE CYTOKINE+ CHEMOTHERAPY /ADOPTIVE CELLULAR THERAPY

• NK CELLS IN VITRO + IL -2 ALSO USES

IFNαTHERAPYEFFECTIVE IN RENALCARCINOMA,

LYMPHOMA

IT INCREASE CYTOLYTIC ACTIVITY OF NK AND MHC I EXPRESSION

TOXIC EFFECTS – FEVER, PULMONARY OEDEMA VASCULAR SHOCK

TNF α and β inhibit tumor induced angiogenesis there by reduced blood flow

And inhibiting tumor growth

Isolate dendritic cellCulture with GM- CSF etc Dendritic cell proliferates thenpriming with tumor antigen& re introduce to host

Isolate tumor cellAdd cytokine gene Re introduced to host

Tumor bearing hostUsing antigen presenting cells 2 methods

T cells stimulated Dendritic cell activated by GM-CSF from expanded tumor cells

ADJUVANT MEDIATED IMMUNITY BOOSTERS

• A number of adjuvants including the attenuated strains of mycobacterium boviscalled bacillus calmette guerin (BCG) & CORYNE BACTERIUM PARVUM have been used to booster immunity

• It activate macrophage, cytokines classII MHC , B7

• GENRERALISED INCRESE IN HUMORAL & CELL MEDIATED IMMUNITY

Adoptive cellular immunotherapy

• Transfer cultured immune cell for anti tumor activity

• Rosenberg - NK cell + IL 2 = LYMPHOKINE ACTIVATED CELL OR LAK CELL

• Chemotherapy +LAK mice has antitumor activity in mice

• research on humans is ongoing

• Side effects- vascular leak syndrome – migration of lymphoid cells and plasma from the peripheral blood vessels in to the tissue

• More effective tumor destruction

Tumor infiltrating lymphocytes

• Variation of previous technique

• TIL is extracted from the inflammatory infiltration around tumor

• With IL 2 expand in enormous no. in vitro

• Expanded for specific tumor recognition

• Reintroduce to host

• Eliminates tumor completely or partially

Monoclonal antibody• Intelligent way• Single antigen• EGFR on tumor cell receptor • Antibody from rat or rabbit bind with it• Breast cancer receptor is HER toxin is

herceptin• Fc part replaced by human antibody• +TOXIN - DIPTHERIA TOXIN & RICIN -GUIDED MISSILE THERAPY• CONJUCATED ANTIBODY – RADIOACTIVE

PARTICLES , TOXINS , CHEMICALS + ANTIBODY

• Rituximab is one of mab commonly used

HUMORAL IMMUNO THERAPY

FUTURE EXPECTATION

• VACCINATION research is on going e.g. HPV vaccine that have,

• low cost

• And Reach every where in the world