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MAP17 (PDZK1IP1) and pH2AX a e po en ial p edic i e
bioma ke s o ec al cance ea men e icacy
Ma ia Ri e o1,2,4,*, Ja ie Peinado-Se ano1,2,3,*, Sand a Muñoz-Gal an1,3, Asuncion
Espinosa-Sánchez1, Elisa Sua ez-Ma inez1, Blanca Felipe-Ab io1,3, Ma ia Ca men
Fe nández-Fe nández1,4, Ma ia Jose O iz1,2 and Amancio Ca ne o1,3
1Ins i u o de Biomedicina de Se illa, HUVR, CSIC, Uni e sidad de Se illa, Se ille, Spain
2Depa men o Radia ion Oncology, HUVR, Se ille, Spain
3CIBER de Cánce , ISCIII, Mad id, Spain
4Depa men o Pa hology, HUVR, Se ille, Spain
*These au ho s con ibu ed equally o his wo k
Co espondence o: Amancio Ca ne o, email: [email p o ec ed]
Keywo ds: MAP17; colo ec al cance ; bioma ke s
Recei ed: June 13, 2018 Accep ed: July 13, 2018 Published: Augus 31, 2018
Copy igh : Ri e o e al. This is an open-access a icle dis ibu ed unde he e ms o he C ea i e Commons A ibu ion License 3.0
(CC BY 3.0), which pe mi s un es ic ed use, dis ibu ion, and ep oduc ion in any medium, p o ided he o iginal au ho and sou ce
a e c edi ed.
ABSTRACT
Rec al cance ep esen s app oxima ely 10% o cance s wo ldwide. P eope a i e
chemo adio he apy inc eases comple e pa hologic esponse and local con ol,
al hough i o e s a poo ad an age in su i o ship and sphinc e sa ing compa ed
wi h ha o adio he apy alone. A e p eope a i e chemo adio he apy, app oxima ely
20% o pa ien s wi h ec al cance achie e a pa hologic comple e esponse o he
emo ed su gical specimen; his esponse may be ela ed o a be e p ognosis and an
imp o emen in disease- ee su i al. Howe e , be e bioma ke s o p edic esponse
and new a ge s a e needed o s a i y pa ien s and ob ain be e esponse a es.
MAP17 (PDZK1IP1) is a small, 17 kDa non-glycosyla ed memb ane p o ein
loca ed in he plasma memb ane and Golgi appa a us and is o e exp essed in a wide
a ie y o human ca cinomas. MAP17 has been p oposed as a p edic i e bioma ke
o eac i e oxygen species, ROS, inducing ea men s in ce ical umo s o la yngeal
ca cinoma. Due o he inc ease in ROS, MAP17 is also associa ed wi h he ma ke
o DNA damage, phosphoH2AX (pH2AX). In he p esen manusc ip , we examined
he alues o MAP17 and pH2AX as su oga e bioma ke s o he esponse in ec al
umo s. MAP17 exp ession a e p eope a i e chemo adio he apy is able o p edic
he esponse o chemo adio he apy, simila o he inc ease in pH2AX. Fu he mo e,
we explo ed whe he we can iden i y molecula a ge ed he apies ha could help
imp o e he esponse o hese umo s o adio he apy. In his sense, we ound ha
he inhibi ion o DNA damage wi h olapa ib inc eased he esponse o adio- and
chemo he apy, speci ically in umo s wi h high le els o pH2AX and MAP17.
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INTRODUCTION
Rec al cance ep esen s app oxima ely 10% o
cance s wo ldwide [1]. In 2012, he e we e 446.801
newly diagnosed cases and 214.727 dea hs a ibu ed o
his en i y in Eu ope [1]. Colo ec al cance was es ima ed
o be he mos equen neoplasm diagnosed in Spain in
2015 [2]. The s anda d o ca e in pa ien s wi h locally
ad anced ec al cance is p eope a i e chemo adio he apy
be o e su gical excision. The addi ion o p eope a i e
adia ion he apy imp o es local con ol and su i al in
his se o pa ien s [3–8]. P eope a i e chemo adio he apy
inc eases he comple e pa hologic esponse and local
con ol, al hough i o e s a poo ad an age in su i o ship
Resea ch Pape
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and sphinc e sa ing compa ed wi h ha o adio he apy
alone [9–13]. A e p eope a i e chemo adio he apy,
app oxima ely 20% o pa ien s wi h ec al cance achie e
a pa hologic comple e esponse in he su gical specimen
emo ed, which may be ela ed wi h a be e p ognosis and
an imp o emen in disease- ee su i al [14]. Howe e ,
be e bioma ke s o p edic esponse and new a ge s a e
needed o s a i y pa ien s and o ob ain be e esponse
a es.
MAP17 is a small, 17 kDa non-glycosyla ed
memb ane p o ein loca ed in he plasma memb ane and
Golgi appa a us [15]. Al hough i s physiological ole is no
ully clea , di e en s udies ha e shown ha i s imula es
sodium-glucose linked anspo e (SGLT), he eby
inc easing glucose and mannose up ake in Xenopus
o oci es [15] and human umo cells [16].
MAP17 is o e exp essed in a wide a ie y o
human ca cinomas [16]. Acco ding o a s udy by
Guija o e al. [16] on ca cinoma umo samples om
di e en localiza ions, MAP17 o e exp ession is >70%
in he o a y, colon, s omach, ce ix and hy oid gland
and app oxima ely 50% in he lung, u e us and ec um.
Fu he mo e, o e exp ession o he p o ein s ongly
co ela es wi h umo p og ession in colon, p os a e,
sa comas and o a ian ca cinomas (P < 0.0001) [16].
Tumo cells ha o e exp ess MAP17 show
pheno ypic ad an ages wi h enhanced p oli e a i e
capabili ies, dec eased apop o ic sensi i i y and inc eased
mig a ion [17]. The mechanism esponsible o he
inc eased umo capabili ies o cells exp essing MAP17
has no ye been desc ibed. MAP17 o e exp ession in i o
ac i a es he No ch pa hway in umo cells, leading o an
inc ease in he s em cell pool [18]. This abe an signaling
ac i a ion may be p esen in a la ge pe cen age o umo s
[18]. A co ela ion be ween MAP17 exp ession and an
in lamma o y pheno ype in umo s and o he in lamma o y
diseases has also been desc ibed. Immunohis ochemical
analysis has con i med local in lamma ion, e en a
he si e o MAP17 exp ession in umo s [19]. Ch onic
in lamma ion is also a cause o neoplas ic ans o ma ion
and p og ession; he e o e, i is likely ha MAP17 plays
an impo an ole in cance de elopmen by egula ing he
immune mic oen i onmen [19].
This inc eased malignan beha io is associa ed
wi h an inc ease in eac i e oxygen species (ROS)
p oduc ion, and ea men o cells wi h an ioxidan s
educes hei umo igenic p ope ies [17]. ROS play a
undamen al ole in cellula physiology. They p omo e
bo h cell p oli e a ion and g ow h and cell dea h, which
is a highly e icacious ool in cance ea men . This dual
mechanism has been ela ed wi h ROS concen a ions in
he cellula en i onmen . A low le els, hey a e in ol ed
in main aining cellula homeos asis and egula e cellula
physiological p ocesses such as p oli e a ion and apop osis
[20]. When he concen a ion o ROS inc eases, hey ac
as oncogene ac i a o s [21] and as in acellula second
messenge s o p oli e a ion and cell g ow h [22, 23].
Howe e , u he inc eases in ROS (close o h eshold
le els) may induce a oxic en i onmen and u n he
physiology o cells owa ds apop osis [24, 25].
The ec opic exp ession o MAP17 inc eases glucose
and mannose up ake, gene a ing an inc ease in ROS le els
as a p oduc o inc eased me abolism [17]. A di ec link
be ween MAP17 and he e minal domain o glucose
anspo e s is also possible, al e ing ion exchanges and
he in acellula edox-balance [26]. Tumo s exp essing
high le els o MAP17 may bene i om he apies ha
inc ease oxida i e s ess. These umo s show inc eased
ROS p oduc ion and could c oss he h eshold oxic le el
easie han non- umo cells wi h oxida i e ea men s [26],
which has been obse ed in umo ypes subjec ed o ROS-
inducing ea men s.
MAP17 exp ession was de ec ed in app oxima ely
70% o umo s om mo e han 200 ce ical umo
samples ob ained om biopsies p io o ea men . A e
ea men wi h cispla in plus adio he apy, high le els o
MAP17 we e ela ed wi h imp o ed pa ien su i al [27].
The e o e, high le els o MAP17 could se e as a ma ke
o good p ognosis in pa ien s wi h ce ical umo s a e
cispla in plus adio he apy ea men [27].
Simila ly, MAP17 has also been p oposed as a
p edic i e bioma ke o la yngeal ca cinoma. Pa ien s
wi h la ynx cance and high MAP17 exp ession in
p e ea men biopsies showed be e ou comes han hose
wi h low MAP17 exp ession [28]. MAP17 exp ession
was associa ed wi h o e all su i al (OS) (p < 0.001),
la yngoesophageal dys unc ion- ee su i al (p = 0.002)
and loco egional con ol (p = 0.016) [28]. The same s udy
ound a posi i e co ela ion be ween MAP17 exp ession
and SGLT (p = 0.022) and high le els o MAP17/SGLT
in combina ion wi h an inc ease in OS (p = 0,028) [28].
MAP17 is also associa ed wi h he ma ke o DNA
damage, phosphoH2AX (pH2AX). When pH2AX was
e alua ed in combina ion wi h MAP17, highe exp ession
o bo h po en ial bioma ke s was associa ed wi h an
imp o emen in la yngoesophageal dys unc ion- ee
su i al (61.35 s. 32.2 mon hs, p = 0.05) and OS (66.6
s 39.8 mon hs, p = 0.01) [29]. In umo s wi h MAP17
o e exp ession, pH2AX, which ac s as a su oga e o
umo damage, could be induced by an inc ease in ROS.
[29] His one H2AX is a a ian o his one H2A and is
implica ed in DNA epai . H2AX becomes phospho yla ed
in esponse o DNA double-s and b eaks and is hen
called gamma-H2AX (γH2AX o pH2AX), which
pa icipa es in he ec ui men o DNA epai p o eins; i
can be phospho yla ed by kinases o he PI3- amily, such
as a axia elangiec asia mu a ed (ATM) and ATMRad3-
ela ed (ATR), in esponse o DNA damage. pH2AX has
been employed as an indica o o un epai ed DNA damage
and has been p oposed as a sensi i e ma ke o cance
p og ession and esponse o cance he apies [30].
In he p esen s udy, we in es iga ed whe he
MAP17 and pH2AX exp ession le els can be de ec ed
in locally ad anced ec al cance a e p eope a i e
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chemo adio he apy and hei ela ionship wi h disease- ee
su i al (DFS) and OS p ognos ic alues. Fu he mo e,
we explo ed whe he we can iden i y molecula a ge ed
he apies ha could help imp o e he esponse o hese
umo s o adio he apy.
RESULTS
MAP17 exp ession in ec al umo samples
Ou coho o 135 samples om pa ien s wi h
locally ad anced ec al cance who ecei ed p eope a i e
chemo adio he apy in he same ins i u ion om 2005 o
2014 (Supplemen a y Table 1) was e alua ed o OS o
compa ison wi h published da a. In ou coho , we ound
a 5-yea OS o 75% (Figu e 1A), which is simila o o he
published coho s [31, 32].
Posi i e MAP17 exp ession was e alua ed by
immunohis ochemis y (Figu e 1B). Inc eased MAP17
p o ein exp ession in he umo samples was de ined o
occu when he pe cen age o s ained umo was highe
han 0.75 (0–3, as indica ed in he M&M) compa ed o
ha o non- umo samples [27, 28], and low exp ession
was de ined by a alue lowe o equal o 0.75. Unde
hese condi ions, 93 (69%) umo samples exhibi ed
high exp ession o MAP17 and 42 (31%) exhibi ed low
exp ession (Figu e 1C). Simila da a we e ob ained when
he mRNA was analyzed in publicly accessible da abases,
such as he Kaise colon [33] h ough he Oncomine
analysis po al (Figu e 1D). The analysis o ou coho
also e ealed ha he le els o MAP17 we e associa ed
wi h he de elopmen o me as ases (p = 0.07). Al hough i
does no each s a is ical signi icance, shows a clea end
(Figu e 1E).
MAP17 exp ession and p ognos ic alues
Pa ien s wi h low MAP17 exp ession also showed a
be e OS (p = 0.064) and DFS (p = 0.380) compa ed wi h
hose wi h high exp ession (Figu e 2A and 2B). Al hough
hese da a do no each s a is ical signi icance, hey show
a clea end, indi iduals wi h highe le els o MAP17 a e
a a highe isk and show a wo se esponse o an icance
ea men s (Figu e 2C and 2D) han hose wi h lowe le els
o MAP17.
Since MAP17 le els we e associa ed wi h
me as ases, we analyzed whe he MAP17 is linked o
his pheno ype o whe he i s diagnos ic capabili y is
independen o he me as ases and analyzed i s su i al
p obabili y. Pa ien s wi h me as ases and high MAP17
le els showed wo se su i al p obabili y han hose wi h
low MAP17 le els (p = 0.7) (Figu e 2E) Al hough i does
no each s a is ical signi icance, shows a clea end.
The e o e, MAP17 is an independen p ognos ic ac o o
me as ases.
Pa hways en iched in genes co ela ing wi h
MAP17 exp ession in ec al umo s
Nex , we used he R2 bioin o ma ics pla o m
o analyze genes and pa hways ha may be associa ed
wi h MAP17 exp ession in ec al umo s. Al e ed genes
associa ed wi h MAP17 exp ession we e mainly ela ed
wi h DNA damage and DNA epai unc ions (Figu e 3).
These genes we e also ela ed wi h signal ansduc ion,
memb ane p o eins, d ug a ge s and de elopmen .
Among he genes ela ed o DNA damage and DNA
epai unc ions, we ound genes in ol ed in he Fanconi
anemia pa hway (27%) homologous ecombina ion (27%),
nucleo ide excision epai (20%), base excision epai
(16%) and misma ch epai (10%).
Phospho yla ion o H2AX (pH2AX) in ec al
umo samples
Posi i e pH2AX exp ession was
immunohis ochemically examined by double-blind
independen obse a ions (Figu e 4A). We de ec ed
inc eased pH2AX p o ein exp ession in some umo
samples compa ed o ha in non- umo samples (Figu e
4A). The le els o pH2AX exp ession we e sco ed by
mul iplying he s eng h o nuclea s aining (0–3) and he
pe cen age o umo cells wi h posi i e nuclei. The cu -
o poin was conside ed 100 (<100 as nega i e, >100 as
posi i e) [29]. Unde hese condi ions, 82 (60%) umo
samples exhibi ed high exp ession o pH2AX and 53
(40%) exhibi ed low exp ession (Figu e 4B).
Low exp ession o pH2AX was associa ed wi h
a be e p ognosis in e ms o OS (p = 0.156), al hough
his esul was no s a is ically signi ican (Figu e 4C).
Howe e , low pH2AX exp ession was no associa ed wi h
DFS (p = 0.659) (Figu e 4D).
When combining pH2AX and MAP17 exp ession,
pa ien s wi h low ma ke alues o bo h p o eins (pH2AX
exp ession < 100 and MAP17 exp ession ≤ 0.75) ob ained
be e DFS (p = 0.188) and OS (p = 0.037) han hose wi h
high alues (pH2AX ≥100 and MAP17 >0.75) (Figu e 5).
The DNA damage inhibi o olapa ib e-sensi izes
MAP17- and pH2AX-posi i e ec al umo s o
adio he apy
I is clea ha pa ien s wi h umo s exhibi ing
high le els o bo h MAP17 and pH2AX ha e a wo se
p ognosis. These esul s may be ela ed o an inc ease in
he DNA damage esponse associa ed wi h MAP17. I is
possible o inc ease he sensi i i y o adio he apy in hese
MAP17+pH2AX umo s by inhibi ing he esponse o
DNA damage (DDR). This poin has been shown in o he
con ex s [34–36] bu no in he con ex o adio he apy-
ea ed ope able locally ad anced ec al cance .
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Figu e 1: MAP17 up egula ion in ec al umo s a e concu en chemo adio he apy. (A) O e all su i al analysis o he
ec al umo coho (Supplemen a y Table 1) used in his s udy. (B) Rep esen a i e pic u es o MAP17-s ained ec al umo samples. An
ROC cu e was used o iden i y he cu -o poin (0.75). (C) Pe cen age o umo s posi i e and nega i e o MAP17 in ou coho o ec al
umo samples (n = 135). (D) MAP17 mRNA exp ession le els in non- umo colon (n = 5) and ec al mucinous adenoca cinomas (n = 4).
(E) MAP17 mRNA exp ession le els in samples om pa ien s wi hou me as asis (NO) s pa ien s wi h me as asis (YES).
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Figu e 2: P ognosis analysis o MAP17 exp ession in ec al umo s a e concu en chemo adio he apy. (A, B)
Associa ion be ween MAP17 p o ein exp ession assessed by IHC o su i al in he ec al umo coho . (A) O e all su i al (OS) and (B)
disease- ee su i al (DFS) Kaplan-Meie su i al cu es based on MAP17 p o ein exp ession. (C) mRNA MAP17 exp ession by isk
g oup in TCGA ec al umo s coho . (D) mRNA MAP17 exp ession by esponde s o non- esponde s in TCGA ec al umo s coho . (E)
Kaplan–Meie accumula ed su i al cu e acco ding o ime o me as asis by MAP17 mRNA exp ession.

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To p o e his poin , we explo ed he le els o MAP17
and pH2AX in a panel o colo ec al cell lines (Figu e 6A, 6B,
Supplemen a y Table 1). We selec ed 2 colo ec al cell lines,
HCT116 wi h high MAP17 and high pH2AX exp ession,
and SW480, wi h low MAP17 and pH2AX exp ession
(Figu e 6A, 6B). These lines we e ea ed wi h di e en
doses o adio he apy ei he in he p esence o absence o he
PARP inhibi o olapa ib (Figu e 6C, 6D). The subop imal
dose selec ed (10 µM) does no induce any signi ican
dec ease in su i al. Radia ion o 2 Gy alone induced a
clea dec ease in su i al in he HCT116 cell line, which
was mo e p onounced in he p esence o olapa ib (Figu e
6C, 6D). A 4 Gy o adio he apy ea men , we obse ed
a u he dec ease in su i al ha was mo e p onounced in
he p esence o olapa ib. These da a indica e ha ea men
wi h subop imal doses o olapa ib p io o adia ion
ea men may dec ease he su i al o MAP17+pH2AX-
posi i e umo s (Figu e 6C). Howe e , hese esul s a e
no main ained in SW480, a cell line wi h low le els o
hese ma ke s. In his case, olapa ib does no induce a
u he dec ease in su i al induced by adio he apy alone
(Figu e 6F).
Since adio he apy ea men o ec al umo s is
concu en wi h chemo he apy, which usually in ol es
5FU, we de e mined whe he he inhibi ion o DNA
epai by olapa ib imp o es chemo he apy ea men in
ec al umo s when applied as concu en chemo he apy.
Bo h cell lines we e ea ed wi h di e en doses o
chemo he apy ei he in he p esence o absence o
subop imal doses o olapa ib (10 µM) (Figu e 6E, 6F).
Olapa ib ea men did no sensi ize SW480 cells, he
line wi h low MAP17 and low pH2AX exp ession, o
5FU ea men (Figu e 6E). Howe e , in he HCT116 cell
line wi h high le els o MAP17 and pH2AX, ea men
wi h subop imal doses o olapa ib caused a signi ican
educ ion in he IC50 alue o 5FU (Figu e 6F).
DISCUSSION
The use o long-cou se chemo adia ion (CRT) o
concu en sho -cou se adio he apy (SCRT) consis en ly
imp o es local con ol a es compa ed o hose om
su ge y alone, pos ope a i e CRT o pos ope a i e
adio he apy [37, 38]. Howe e , i s use does no
consis en ly ansla e o OS [39].
The e o e, mul idisciplina y in o ma ion has
become impo an when making decisions ega ding
CRT. These decisions a e based on he combina ion o
magne ic esonance imaging (MRI), umo and pa ien
cha ac e is ics and labo a o y expe imen al indings.
Ve y ew obus molecula s udies ha e elucida ed
he mechanism o chemo adia ion esis ance. Ve y ew
p omising p edic i e bioma ke s ha e been sugges ed,
including EGFR, hymidyla e syn hase, PI3K, me hyla ion
o p o eins in ol ed in he as/MAPK pa hway [40–44].
Fu he mo e, i has been epo ed ha di e en genomic
signa u es iden i y esponde s and non- esponde s om
whole-genome analysis [39, 42]. Howe e , none o he
signa u es om he gene mic oa ay p o ile on locally
ad anced ec al cance ha e been success ully alida ed
as a diagnos ic o p ognos ic ool applicable o ou ine
clinical p ac ice [39].
Figu e 3: Gene On ology pa hways co ela ing wi h MAP17 exp ession. Genes ha co ela ed wi h MAP17 exp ession
(Pea son < −0.35, > 0.35) we e selec ed. Gene On ology analysis was applied, and he mos ep esen a i e signaling pa hways a e
p esen ed.
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Ou wo k shows ha pa ien s wi h high MAP17 a e
associa ed wi h wo se OS and he p esence o me as asis.
Fu he mo e, he associa ed high le els o MAP17
and pH2AX showed be e p ognos ic capabili y han
MAP17 o pH2AX alone. The ac ha he combina ion
o MAP17 and pH2AX has be e p ognos ic capabili y in
ec al umo s is consis en wi h o he s in la yngeal cance
in which high le els o MAP17 (and o a g ea e ex en ,
Figu e 4: Phospho yla ion o γH2AX (p-H2AX) in ec al umo s a e concu en chemo adio he apy. (A) Rep esen a i e
pic u es o MAP17-s ained ec al umo samples. (B) Pe cen age o umo s posi i e and nega i e o MAP17 in ou coho o ec al umo
samples (n = 135). An ROC cu e was used o iden i y he cu -o poin (100). (C) O e all su i al (le ) and disease- ee su i al ( igh )
analysis o he ec al umo coho (Supplemen a y Table 1) used in his s udy. (D) Disease- ee su i al analysis o he ec al umo coho
(Supplemen a y Table 1) used in his s udy
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high MAP17 and high pH2AX) co ela ed wi h imp o ed
pa ien su i al a e ea men [28, 45, 46].
In his se ing, ou analysis in ec al cance showed
a clea bu no s a is ically signi ican ela ionship
be ween low MAP17 p o ein exp ession and inc eased
OS, sugges ing ha MAP17 exp ession is an independen
bioma ke o su i al. In ac , high MAP17 le els
demons a ed wo se OS han low le els.
pH2AX was also ela ed wi h OS in he same
coho o 135 pa ien s wi h ec al cance . Ou da a sugges
ha inhe en DDR pa hway ac i a ion (measu ed by
he endpoin o γH2AX phospho yla ion) is a aluable
p ognos ic ma ke in pa ien s wi h ec al ca cinoma who
ecei ed adia ion he apy.
I has been p oposed ha he DDR ne wo k may
se e as an inducible ba ie o con ol he ini ial s eps
o umo de elopmen by inducing p53-dependen
senescence o apop osis [46–49]. Ongoing ch onic DDR
ac i a ion a o s he ou g ow h o malignan clones wi h
gene ic o epigene ic de ec s in a DNA epai mechanism,
such as hose in ol ed in he DDR pa hway [49]. Ou
samples om al eady malignan umo s (s ages II-IV)
co ela ed wi h a wo se onse o disease. I is likely ha
DNA damage de ec s ha induce DDR ac i a ion a e
ca ied h ough he malignan p ocess and i is possible
ha o he p o eins a e mu a ed in he p ocess, esul ing in
he DNA-damaging e ec o adio he apy.
We also showed ha he combina ion o MAP17 and
pH2AX has a p edic i e ole in pa ien s wi h ec al cance
ea ed wi h CRT. Taking in o accoun he combined
analysis o pH2AX and MAP17, we hypo hesize ha he
DDR pa hway plays an essen ial ole in he p edic i e
ou come o ec al cance . Fu he mo e, p oo o concep
analysis o umo cells ea ed wi h olapa ib indica ed
ha DNA epai pa hway inhibi ion sensi izes umo cells
wi h high MAP17 and pH2AX le els o adio he apy and
concu en chemo he apy.
High MAP17 le els a e associa ed wi h OS. MAP17
inc eases endogenous ROS [26, 27, 50], which induce
DNA damage [51]. Da a om ou s udy and o he s sugges
ha high le els o MAP17 induce ROS, which inc ease
DNA damage and DDR signaling; his is deno ed by
highe pH2AX le els [45, 51]. Upon he inhibi ion o DNA
damage o a u he inc ease in damage by RT ea men ,
umo s a e mo e likely o unde go apop osis. Fu he mo e,
p oo o p inciple expe imen s in i o demons a ed ha
DNA damage inhibi o s such as olapa ib inc eased he
sensi i i y o MAP17-exp essing cells, con i ming he
ele ance o he oxida i e s a us o he umo s in esponse
o adia ion. Pa ien s who a e unlikely o espond could be
o e ed an al e na i e app oach o he apy by co-adju an
o concu en chemo he apy combined wi h inhibi ion o
he DNA damage esponse pa hway.
The e o e, ou da a con i m ha pH2AX (and i s
combina ion wi h MAP17) le els, is a ma ke o s uc u al
DNA damage in ec al umo s and hus may se e as a
no el aluable and easily applicable p edic i e bioma ke
o ec al ca cinoma.
In conclusion, cu en ea men depends on clinical
and labo a o y p edic i e and p ognos ic ma ke s. Ou
s udy ocused on he use o wo p edic i e ma ke s o
explain some a iabili y in esponse o s anda d ea men .
Figu e 5: Combined MAP17 and phospho yla ion o γH2AX (p-H2AX) analysis o su i al in ec al umo s a e
concu en chemo adio he apy. O e all su i al (le ) and disease- ee su i al ( igh ) analysis o he ec al umo coho
(Supplemen a y Table 1) used in his s udy. Cu -o poin s a e he same as hose lis ed abo e; high MAP17 (0 > 0.75), high pH2AX (> 100).
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MAP17 and pH2AX, ei he alone o in combina ion, le els
ob ained a e RT and co-adju an he apy o concu en
chemo he apy ea men a e p edic i e ma ke s o p edic
he esponses o ec al umo s. Fu he mo e, ou wo k
o e s an adjus ed he apy o pa ien s wi h a combina ion
o hese bioma ke s (high MAP17 + high pH2AX) by
he addi ion o olapa ib (o o he DNA epai inhibi o s
+ RT ea men ). In u u e ials, assessing CRT and
neo-, coadju an o concu en chemo he apy o ec al
cance should be e alua ed p ospec i ely. I is clea ha
Figu e 6: The DNA damage inhibi o olapa ib e-sensi izes MAP17- and pH2AX-posi i e ec al umo s o adio he apy
ea men . (A) Wes e n blo analysis and ela i e quan i ica ion o he p o ein le els o phospho-γ-H2AX in colon umo cell lines. (B)
RT-qPCR showing he RNA le els o MAP17 in HCT116 and SW480 colon umo cell lines. Samples we e no malized o GAPDH.
(C and D) Pe cen age o su i al ac ion a e olapa id ea men (10 µM), adiology ea men (2 and 4 Gy) o hei combina ion in
HCT116 and SW480 colon umo cell lines. (E and F) De e mina ion o he IC50 alue (concen a ion o he d ug necessa y o induce 50%
cell dea h) o SW480 and HCT116 and colon umo cells lines ollowing ea men wi h olapa id and/o 5FU.