Seminario biología molecular

1. Sara Montoya Cédula
Medical Student, third semester
Universidad Pontificia Bolivariana

2. INTRODUCTION
Apoptosis is a form of programmed cell death
that occurs in multicellular organisms.
Biochemical events lead to characteristic cell
changes (morphology) and death.
Cellular senescence is the process initiated
in response to stress and damage
occurring in a cell and constitutes an
alternative route of response to
programmed cell death and is of vital
importance to suppress the formation of
cancer cells.
APOPTOSIS SENESCENCE

3. INTRODUCTION
PKC
Protein kinase C (PKC) plays critical roles in signal transduction and cell regulation. PKC constitutes a
multigene family classified into conventional (α, βI, βII, γ), novel (δ, ε, η, θ) and atypical (ξ, ι) isozymes.
Tumor promoting phorbol esters are potent activators of conventional and novel PKCs and can
substitute for the physiologic stimulator diacylglycerol (DAG).
PKCη is a unique member of the novel PKC isozyme family. This is the only novel PKC that either
resists downregulation or is upregulated by phorbol esters, but it has been implicated in both tumor
promotion and tumor suppression.

4. OBJECTIV
E
Determine the differential effects of
protein kinase C-eta on apoptosis
versus senescence

5. METHODS
CELL CULTURE
FUNDAMENTAL PRINCIPLE:
In this process the cells are grown under controlled
conditions, generally outside their natural
environment
USED TO:
To maintain the cells 'in vitro', conserving to the
maximum their physiological, biochemical and
genetic properties

6. METHODS
TRANSFECTION
FUNDAMENTAL PRINCIPLE:
It consists of the introduction of an external DNA
into eukaryotic cells
USED TO:
To get the cells to express a protein of interest. The
transfection of interfering RNAs have been carried
out as suitable mechanisms to suppress the
expression of a particular gene

7. METHODS
WESTERN BLOT ANALYSIS
FUNDAMENTAL PRINCIPLE:
It is a technique that is based on the antigen-antibody reaction, the first thing we
do is make a separation of the proteins by means of an electrophoresis by
molecular weight and electric charge, later the protein that I am studying with an
antibody is identified
USED TO:
To identify the expression of PKCn

8. METHODS
WESTERN BLOT ANALYSIS

9. RESULTS
Control tube: +
(expressed, thick band)
PKC: -
(not expressed)
PARP: Decrease a bit
with PKC

10. RESULTS
Control tube: +
Mcl1: -
(both A and B)
PKCn: A-, B+
PARP: Decrease a bit in
MCF-7 cells (A) with
siRNAs, but in T47D cells
(B) doesn´t change

11. RESULTS
Control tube = +
PKCn = -
None = +

12. RESULTS P27: -
PKCn: +
Control tube: +

13. DISCUSSION
AUTHOR WHAT DID HE PROPOSE? WAS IT TRUE OR FALSE?
D. Pal, A. Basu
We have recently shown that PKCη
positively regulates the anti-apoptotic
Bcl-2 family protein Mcl-1 by
preventing its degradation via the
proteasomal pathway
D. Pal, A. Basu
There are controversies regarding the
role of PKCη in tumor promotion
versus tumor suppression
A. Basu
Although MCF-7 cells do not express
caspase-3, it can induce apoptosis

14. CONCLUSIONS
1. In the article it was found that the fall of PKCη induces senescence and confers resistance to
chemotherapeutic drugs. This could be useful to protect tissues that do not need to undergo
chemotherapy, and thus make this procedure more localized and less harmful.
2. They showed that positive regulation of p27 was responsible for the induction of senescence
caused by PKCη deficiency, and depletion of p27 could restore apoptosis in cells depleted in
PKCη. In the medical field this would be useful because if apoptosis is induced it could serve as a
treatment for cancer.