Alejandra Mejía MoraDaniela Martínez Laverde

3º Semestre medicina U.P.B

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Texto adicional texto adicional

Texto adicional texto adicional

Masaharu Akiyama, Kohji Ozaki, Takeshi Kawano, Osamu Yamada Kiyotaka Kawauchi, Hiroyuki Ida, Hisashi Yamada.

TELOMERASE ACTIVATION AS A TELOMERASE ACTIVATION AS A REPAIR RESPONSE TO RADIATION-REPAIR RESPONSE TO RADIATION-

INDUCED DNA DAMAGE IN Y79 INDUCED DNA DAMAGE IN Y79 RETINOBLASTOMA CELLSRETINOBLASTOMA CELLS

INTRODUCTION

TELOMERE

TelomeraseTelomerase

Ribonucleoprotein enzyme made of protein and RNA subunits.

Found in fetal tissues, adult germ cells, and also tumor cells.

Elongates chromosomes by adding TTAGGG sequences.

Has a very low activity in somatic cells, and high in “immortal cell.

Cellular aging It is due to the shortening of chromosomal telomeres.

TelomeraseTelomerase

•Reverse transcriptase protein (TERT) - Essential telomerase N-terminal domain (TEN). - Telomerase RNA-binding domain (TRBD). - Reverse transcriptase domain (RT). - C-terminal extension (CTE).

• RNA component (TR). • Dyskerin protein complex (blue).•Telomeric DNA.

TelomeraseTelomerase

TelomeraseTelomerase

Retinoblastoma

DNA RepairDNA Repair

DNA RepairDNA Repair

DNA damageDNA damage

• Cancer cells are a type of malignant cell that multiply until they form a tumor that grows uncontrollably.

• Detected in human cancer cells and is found to be 10-20 times more active than in normal body cells.

• Telomerase activity off/on.

Telomerase and cancerTelomerase and cancer

AssociationAssociation

General objective

• Investigate the molecular mechanism of IR-induced telomerase activation in human retinoblastoma Y79 cells.

Materiales y métodosMateriales y métodos

Cultivo y reactivos Citometría de flujo Ensayo de la telomerasa Transcriptasa inversa - PCR Immunoblot

RPMI 1640

Células retinoblastoma Y79

Suero fetal bovino (10%)• L-glutamina• Penicilina• Estreptomicina

5% CO2

100% humedad

1

2 3 Wortmanina Ácido okadaico

Cultivos y reactivosCultivos y reactivos

Análisis del ciclo célular

FACSCalibur

Citometría de flujoCitometría de flujo

Análisis de las células apoptóticas

Citometría de flujoCitometría de flujo

Ensayo de telomerasaEnsayo de telomerasa

Transcriptasa inversa-PCRTranscriptasa inversa-PCR

Transcriptasa inversa-PCRTranscriptasa inversa-PCR

ImmunoblotImmunoblot

Efectos del IR en la actividad telomerasa y expresión hTERT

Resultados

Efectos IR en actividad de telomerasa vs tiempo de exposición

Resultados

Expresión de hTERT (RNAm)

Resultados

Efecto de IR en el ciclo célular

2 Gy

Resultados

5 Gy

Resultados

Resultados

10 Gy

Resultados

Efecto IR sobre la apoptosis

Resultados

Efecto de IR en moléculas de respuesta al daño de DNA

Resultados

Efectos de la IR en la expresión de la proteína hTERT

Resultados

Efectos producidos por la Wortmanina

Efectos producidos por el ácido ocadaico

Resultados

Discussion

REFERENCE WHAT THEY SAID AGREE OR DESAGREE

M. Natarajan, S. Mohan, R. Konopinski, F. Leteurtre, X. Li, E. Gluckman, E.D.

Carosella, E. Fenig, E. Beery, S. Lichtenberg, Y. Nordenberg, M.

“Telomerase activity is increased 12–24 h after a IR dose of less than 10 Gy

but is decreased only after a dose greater than 10 Gy”.

Agree

Y. Yan, P.T. Cao, P.M. Greer, E.S. Nagengast, R.H. Kolb, M.C. Mumby, K.H.

Cowan.

“The G2/M checkpoint prevents cells from initiating mitosis when they sustain DNA damage during G2 or when they enter the G2 phase with unrepaired DNA damages sustained during previous S or G1 phases”.

Agree

R.A. Tamakawa, H.B. Fleisig, J.M.Y. Wong.“Proteins of the MAPK family, such as p38, JNK, and ERK, are also activated by IR in response to genotoxic stress”. Agree

S.S. Kang, T. Kwon, D.Y. Kwon, S.I, J. Haendeler, J. Hoffmann, S. Rahman, A.M.

Zeiher, S. Dimmeler.

“Okadaic acid, a PP2A inhibitor, is known to activate Akt through its

phosphorylation, resulting in increased telomerase activity”.

Agree

Conclusions

• Ionizing radiation (IR) causes DNA damage, which generates multiple processes inside the cell.

• It is very important to begin any treatment for retinoblastoma avoiding the appearance of secondary cancers.

Conclusions

• In studies related to DNA damage is important to analyze the cell cycle and the percentage of apoptotic cells.

• Telomerase activation is essential for repairing DNA extremes damaged during the IR

AlejandraMejía

Mapas conceptuales

Mapas conceptuales

Daniela Martínez

Bibliography

• MARTINEZ SÁNCHEZ, Lina María. Biología molecular. 7 ed. Medellín: UPB. Fac. de Medicina, 2013. 47-51, 85-88 p.

• Masaharu Akiyama, Kohji Ozaki, Takeshi Kawano, Osamu Yamada Kiyotaka Kawauchi, Hiroyuki Ida, Hisashi Yamada. “Telomerase activation as a repair response to radiation-induced DNA damage in y79 retinoblastoma cells”. 5 July 2013.