Abstracts for the 25th Annual Scientific Meeting of the International ...

J Immunother Volume 33, Number 8, October 2010
Abstracts
produce IL-17A during in vivo expansion. Even though inability of
T cells to form memory had been previously attributed to the early
loss of CD27 expression we demonstrated that in vitro generated
Th17-polarized cells exhibited lower levels of multiple markers of
T cell senescence, including Klrg1, FasL, CD25 and PD-1. They
also produced more IL-2, had high levels of the pro-survival factors
bcl-2 and bcl-6 and low expression of its target, prdm1 that encodes
transcriptional repressor Blimp1, a hallmark molecule of terminally
differentiated effectors. Using serial global gene expression profiling
of adoptively transferred cells, we found that Th17-polarized
cells rapidly acquired some Th1-like properties including t-bet and
IFN-g expression, however Th17-derived memory population was
readily distinguished based on its molecular signature and had
characteristics closely mimicking a pattern found in highly active
CD8+ T memory stem cells described in our previous work. Th17-
dervied memory cells expressed high levels of multiple self-renewal
and pro-survival-associated transcription factors and regulators,
had reduced expression of prdm1, as well as low levels of the
phenotypic markers of terminal differentiation, including pd1,
klrg1, klrd1 and granzymes, in contrast to higher levels of CCR7
and il-7r. In summary, we report that Th17-derived cells expressed
more ‘‘stem-like’’ characteristics distinct form Th1-derived effectors
as evidenced by their molecular signature and dramatically enhanced
ability to survive and reject tumor. This suggests that Th17-
polarizing conditions trigger a distinctive developmental program
representing a promising avenue for the development of potent, new
T cell-based immunotherapies of cancer and other diseases.
Artifical MicroRNA Targeting Programmed Death Receptor-1
to Enhance Adoptive Cell Transfer Therapy for Cancer
Tristen S. Park, Takashi Inozume, Mojgan Ahmadzadeh, Ken-ichi
Hanada, James Yang, Steven A. Rosenberg, Richard A. Morgan.
Surgery Branch, National Institutes of Health, Bethesda, MD.
Melanoma has the unique characteristic of inducing anti-tumor
lymphocytes during tumor growth. Tumor Infiltrating Lymphocytes
(TIL) demonstrate the ability to recognize and lyse tumor
cells in vitro, and the infusion of large numbers of these
lymphocytes have resulted in a 49% to 72% response rate in
patients with metastatic melanoma.Yet these naturally occurring
anti-tumor lymphocytes can often be anergized in vivo, by the
suppressive tumor microenvironment. Further improvement to
TIL therapy may be realized by targeting negative signaling
pathways in the administered TIL.
Programmed death receptor-1 (PD-1) is an immunoinhibitory
receptor that is expressed in CD4 and CD8 positive lymphocytes.
Interaction between PD-1 and its ligands PD-L1 and PD-L2 deliver
a negative signal to lymphocytes. PD-L1 is expressed in a variety of
human tumors including melanomas. It was recently shown that
in melanoma, PD-1 expressing TIL displayed impaired effector
function compared with PD-1 negative TIL. We observed that PD-
1 levels were upregulated in TIL and PBL when cocultured with
matched melanoma lines in vitro. This suggests that the tumor
microenvironment may play a role in the induction and maintenance
of PD-1 expression on tumor reactive cells and that PD-1
on TIL may impair the antitumor immune response in patients.
To investigate the PD-1/PD-L1 interaction in a defined in vitro
setting, PBL were retrovirally engineered to express PD-1 with
either a Mart-1 specific TCR or a HMW (High molecular weight)
specific Chimeric Antigen Receptor (CAR). In coculture assays
against melanoma lines 1300, 624, 526 engineered to express PD-
L1, these Mart-1 TCR/PD-1+ PBL demonstrated impaired tumor
recognition with an approximately 50 percent reduction in
Interferon-g (IFN-g) secretion in the PBL of three donors. HMW
CAR/PD-1+ PBL also demonstrated approximately 50 percent
reduction in IFN production in a coculture assay with mel 1300,
888, 526, 624 expressing PD-L1.
Antibodies that block the PD-1/PD-L1 interaction are currently in
Phase I/II clinical trials, but a more selective approach may be the
specific targeting of PD-1 in tumor specific T cells using RNA
interference. We are investigating if PD-1 expression in TIL can be
silenced using a microRNA-based system. Short hairpin RNA
sequences targeting PD-1 were identified to downregulate the expression
of PD-1 by 50% to 70% in both T cell lines and peripheral
blood lymphocytes. Using these shRNA sequences we are constructing
an optimized microRNA-based retroviral vector for the engineering
of tumor infiltrating lymphocytes. The downregulation of PD-1 in
TIL,mayleadtoimprovedanti-tumoractivityinvitroandinvivo.
Adoptive T Cell Therapy for Metastatic Melanoma: The MD
Anderson Experience
Laszlo G. Radvanyi, Chantale Bernatchez, Minying Zhang,
Priscilla Miller, Michelle Glass, Nicholas Papadopoulos, Patrick
Hwu. Melanoma Medical Oncology, MD Anderson Cancer Center,
Houston, TX.
Adoptive cell therapy (ACT) using tumor-infiltrating lymphocytes
(TIL) is a promising treatment for metastatic melanoma. Here, we
report on the results of an ongoing Phase II clinical trial testing
ACT in metastatic melanoma patients regardless of HLA subtype.
Autologous TIL were expanded in large-scale using anti-CD3 and
IL-2 and then infused into patients following transient lymphodepletion.
This was followed by high-dose IL-2 therapy. The best
overall response was determined and correlated with T cell phenotype
as well as telomere length. The persistence of specific TCR clonotypes
after infusion was also tracked. Altogether, 30 patients have been
treated with clinical response data available from 25 patients (as of
June 20, 2010). Overall, 13/25 (52%) patients have had a clinical
response (PR/CR), with one patient having an ongoing PR for >22
months and another patient having a CR. A higher percentage and
number of CD8+ T cells (P