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Graduate   Category:  Health  Sciences   Degree  Level:  Doctoral   Abstract  ID#  1244

 

Dynamic  Profiling  of  Immuno-­‐Oncological  Interac6on  for  Mul6ple  Myeloma  at  Single  Cell  Resolu6on  Using   Droplet  Microfluidics   Pooja  Sabhachandani  1*,  Saheli  Sarkar  1*,  Dina  Stroopinksi  2,  Kristen  Palmer  2,  Noa  Cohen  1,  Jacalyn  Rosenbla@  2,  David  Avigan2  and  Tania  Konry1     1  Northeastern  University,  PharmaceuEcal  Science,  Boston,  MA,  2  Beth  Israel  Deaconess  Medical  Centre,  Medicine,  Boston,  MA   *Equal  ContribuEon  

ABSTRACT:   Immune   escape   mechanisms   are   used   by   tumors   to   evade   immune   surveillance,   which   promotes   progression   of   cancer.   Cell-­‐based   vaccines   are   being   widely   studied   as   therapeuEc   agents   to   induce   clinically   meaningful   anE-­‐tumor   immunity.   However,   heterogeneity  in  immune  interacEons  could  compromise  the  efficacy  of  these  vaccines.  Thus,  interrogaEon  of  cell  based  vaccines  at  various  stages  of  acEvaEon  and  effector  funcEon  at  single  cell  level  may  be  of  consequence  in  assessing  the  beneficial  effects  of  vaccines  in   tumor  microenvironment.  In  this  study,  we  describe  a  droplet  microfluidic  system  for  analysis  of  Immunological  synapse  (IS)  formaEon  between  dendriEc  cells  (DCs)  and  T  cells  for  the  laWer's  acEvaEon  .  We  co-­‐encapsulated  DCs  with  T  cells  and  observed  heterogeneous  cell   interacEon.  Individual  non-­‐acEvated  DCs  interacted  transiently  with  T  cells,  whereas  anEgen-­‐loaded  DCs  formed  both  transient  and  stable  contacts,  where  the  duraEon  of  the  contacts  varied  from  cell  to  cell.  AcEvaEon  of  T  cells  was  indicated  by  increased  intracellular   calcium  signaling.    AddiEonally,  we  assessed  the  effecEveness  of  two  different  DC  vaccines,  one  acEvated  with  tumor  lysate  and  the  other  a  hybrid  DC-­‐tumor  cell  fusion.  These  vaccines  were  co-­‐encapsulated  with  T  cells  and  mulEple  myeloma  (MM)  cell  line  in  droplets.  Serial   interacEon  between  DCs  and  T  cells  and  T  cells  and  MM  cells  resulted  in  MM  cell  death.  To  our  knowledge,  this  is  the  first  report  of  dynamic  analysis  of  DC  vaccines  at  single  cell  resoluEon  in  microfluidic  pla[orm.  This  integrated  droplet  microarray  can  potenEally  be  used  to   monitor  experimental  cancer  therapeuEcs,  funcEonal  phenotyping  and  heterogeneity  of  cellular  response.  

INTRODUCTION  

It  is  postulated  that  tumor  growth  and  progression  is  a  virtue  of  opEmal  tumor  microenvironment.  The  immune  system  is  said  to   have  a  paradoxical  role  in  tumor  microenvironment  where  it  can  either  downregulate  tumor  growth  by  destroying  cancer  cells  and   inhibiEng   their   proliferaEon   or   promote   tumor   progression   by   promoEng   growth   of   tumor   cells   in   an   immunocompetent   host   by   establishing  favorable  condiEons  within  the  tumor  microenvironment.  The  combinaEon  of  these  processes  is  described  as  cancer   immunoediEng  (1).     DendriEc   cells   (DCs)   are   criEcal   anEgen   presenEng   cells   (APCs)   that   present   tumor   anEgens   to   tumor-­‐infiltraEng   T   lymphocytes.   However,   DC   maturaEon   and   acEvaEon   can   be   suppressed   in   the   tumor   microenvironment,   prevenEng   adequate   anEgen   presentaEon   to   T   cells.   Tumor-­‐specific   DCs   have   been   shown   to   interact   with,   and   acEvate,   T   cells   in   vivo   and   in   vitro   (2).   However,   these   T   cells   have   no   cytolyEc   acEon   on   of   tumor   cells.   This   suggests   that   acEvaEon   of   adapEve   immunity   in   tumor   microenvironment  may  be  heterogeneous  or  ineffecEve  by  itself,  requiring  a  co-­‐sEmulatory  signal  to  downregulate  tumor  growth.   The  development  of  DC  based  cancer  vaccines  are  one  of  the  most  potent  cancer  vaccines  in  clinical  development  as  they  can  be   loaded   ex   vivo   with   tumor   anEgens   and   injected   into   paEents   to   generate   long-­‐term   CD4+   and   CD8+   T   cell   responses   that   can   miEgate  cancer.  However,  dynamic  characterizaEon  of  their  responses  and  interacEons  with  T  cells  and  tumor  cells  is  important  to   address  prior  to  clinical  applicaEon.  We  have  developed  a  droplet  microfluidics-­‐based  pla[orm  to  chemically  isolate  individual  cells   and  observe  phenotypic  changes  subsequent  to  cell-­‐cell  interacEon.    

  METHOD   Droplet  Genera6on,  Cell  Co-­‐encapsula6on  and  cell  velocity  mapping  In  Microfluidic  PlaJorm                            

Fig.   1.   Cell   co-­‐encapsula6on   in   droplet   microfluidic   plaJorm.   (A)   SchemaEc   of   integrated   three-­‐inlet   droplet   generaEon   and   microarray   device.   (B)   GeneraEon   of   nanoliter   droplets.   (C)   Droplets   loaded   in   microarray   for   stable   docking(D)   Morphology   of   single   DC   and   T   cell   in   droplet.  Inset:  Magnified  image  of  dendrite  extension  by  DC.  (E)  Cellular  exocytosis  observed  in  droplet.  Inset:  Magnified  image  of  vesicles   secreted   by   DC   at   4hrs.   Scale   bar:   20µm.   (F)   RepresentaEve   mean   velocity   of   T   cells,   DC   and   RPMI-­‐8226   cells   in   droplet.   (G)   Decrease   in   velocity  as  cells  near  each  other  and  form  conjugate.  The  onset  of  contact  period  is  indicated  by  u.  RPMI-­‐8226  cell  died  at  240min.  Scale  bar:   20µm.   ACKNOWLEDGEMENTS   This  work  was  funded  by  NIH/NCI  grant  R21  [RM11-­‐014]  awarded  to  T.K.  The  authors  are  grateful  to  Abhinav  Gupta,  Vinny  Motwani,  Sneha   Verghese  and  Sai  MynampaE  at  Northeastern  University  for  their  assistance  in  fabricaEon  of  microfluidic  devices  and  data  analysis.         REFERENCES:   Smyth  MJ,  Dunn  GP,  Schreiber  RD.  Adv  Immunol.  2006;90:1-­‐50;  2.  Engelhardt  JJ,  Boldajipour  B,  et  al.  Cancer  Cell.  2012  ;21(3):402-­‐17.  

RESULTS   Dynamic  Profiling  Of  Dendri6c  Cell,  T  Cell  And  Mul6ple  Myeloma  Tumor  Cell  Intera6ons  

                            Fig     2.  Dynamic  monitoring  of  interacEon  between  acEvated  DC  and  T  cells  in  

microfluidic   droplets.   (A)   DCs   were   pulsed   with   OVA-­‐FITC     (100   µg/mL,   16hrs)  and  CCL21(25ng/mL,  2hrs)  and  co-­‐encapsulated  with  untreated  T  cells     in  droplets.  OVA-­‐FITC    expression  on  DC  surface  is  indicated  by  arrowheads.   T  cells  are  labeled  with  CMTPX  tracker  (red),  which  is  transferred  to  the  DCs     over     Eme.  A  series  of  Eme-­‐lapse  images  of  the  same  droplet  is  shown  over  a   period   of   1hr.   Images   were   obtained   every   5min.   Scale   bar:   20µm.   (B)     Analysis   of   the   types   of   interacEon   between   DC   and   T   cell:     no   interacEon     over  a  period  of  5hrs  (-­‐),  conEnuous  interacEon  due  to  conjugate  formaEon     disconEnuous   interacEon   defined   by   short   periods   of   aWachment   and   and   detachment.   DCs   were   either   acEvated   by   pre-­‐treatment   with   OVA-­‐FITC   and     CCL21   (Ag   acEvated)   or   untreated   (Non-­‐acEvated).   (C)   Cells   undergoing     disconEnuous   interacEon   were   further   categorized   into   transient   (≤10     minutes  of  contact)  and  stable  (≥  10minutes)  interacEon.  (D)  DistribuEon  of     contact   Emes   between   DC   and   T   cells   (outliers   are   indicated).   The   data   is   represented   as   mean   ±   SEM   of   n=3   independent   experiments.   P