13 research outputs found
Immunogenic Cell Death Amplified by Co-localized Adjuvant Delivery for Cancer Immunotherapy
Despite their potential, conventional whole-cell cancer vaccines prepared by freeze-thawing or irradiation have shown limited therapeutic efficacy in clinical trials. Recent studies have indicated that cancer cells treated with certain chemotherapeutics, such as mitoxantrone, can undergo immunogenic cell death (ICD) and initiate antitumor immune responses. However, it remains unclear how to exploit ICD for cancer immunotherapy. Here, we present a new material-based strategy for converting immunogenically dying tumor cells into a powerful platform for cancer vaccination and demonstrate their therapeutic potential in murine models of melanoma and colon carcinoma. We have generated immunogenically dying tumor cells surface-modified with adjuvant-loaded nanoparticles. Dying tumor cells laden with adjuvant nanodepots efficiently promote activation and antigen cross-presentation by dendritic cells in vitro and elicit robust antigen-specific CD8α+ T-cells in vivo. Furthermore, whole tumor-cell vaccination combined with immune checkpoint blockade leads to complete tumor regression in 78% of CT26 tumor-bearing mice and establishes long-term immunity against tumor recurrence. Our strategy presented here may open new doors to "personalized" cancer immunotherapy tailored to individual patient's tumor cells. Keywords: cancer immunotherapy; cancer vaccine; Cell engineering; innunogenic cell death; nanoparticl
Selfâhealing encapsulation and controlled release of vaccine antigens from PLGA microparticles delivered by microneedle patches
There is an urgent need to reduce reliance on hypodermic injections for many vaccines to increase vaccination safety and coverage. Alternative approaches include controlled release formulations, which reduce dosing frequencies, and utilizing alternative delivery devices such as microneedle patches (MNPs). This work explores development of controlled release microparticles made of poly (lacticâcoâglycolic acid) (PLGA) that stably encapsulate various antigens though aqueous active selfâhealing encapsulation (ASE). These microparticles are incorporated into rapidâdissolving MNPs for intradermal vaccination.PLGA microparticles containing Alhydrogel are loaded with antigens separate from microparticle fabrication using ASE. This avoids antigen expsoure to many stressors. The microparticles demonstrate biâphasic release, with initial burst of soluble antigen, followed by delayed release of Alhydrogelâcomplexed antigen over approximately 2âmonths in vitro. For delivery, the microparticles are incorporated into MNPs designed with pedestals to extend functional microneedle length. These microneedles readily penetrate skin and rapidly dissolve to deposit microparticles intradermally. Microparticles remain in the tissue for extended residence, with MNPâinduced micropores resealing readily. In animal models, these patches generate robust immune responses that are comparable to conventional administration techniques. This lays the framework for a versatile vaccine delivery system that could be selfâapplied with important logistical advantages over hypodermic injections.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147859/1/btm210103-sup-0001-supinfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147859/2/btm210103_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147859/3/btm210103.pd
Engineered Ovalbumin Nanoparticles for Cancer Immunotherapy
Ovalbumin (OVA) is a protein antigen that is widely used for eliciting cellular and humoral immune responses in cancer immunotherapy. As an alternative to solute OVA, engineering approach is developed herein towards protein nanoparticles (pNPs) based on reactive electrospraying. The resulting pNPs are comprised of polymerized OVA, where individual OVA molecules are chemically linked via poly(ethylene glycol) (PEG) units. Controlling the PEG/OVA ratio allows for fineâtuning of critical physical properties, such as particle size, elasticity, and, at the molecular level, mesh size. As the PEG/OVA ratio decreased, OVA pNPs are more effectively processed by dendritic cells, resulting in higher OTâI CD8+ cells proliferation in vitro. Moreover, pNPs with lower PEG/OVA ratios elicit enhanced lymphatic drainage in vivo and increased uptake by lymph node macrophages, dendritic cells, and B cells, while 500 nm OVA pNPs show poor draining lymph nodes delivery. In addition, pNPs with lower PEG/OVA ratios result in higher antiâOVA antibody titers in vivo, suggesting improved humoral immune responses. Importantly, OVA pNPs result in significantly increased median survival relative to solute OVA antigen in a mouse model of B16F10âOVA melanoma. This work demonstrates that precisely engineered OVA pNPs can improve the overall antiâtumor response compared to solute antigen.As an alternative to solute antigens for cancer immunotherapy, protein nanoparticles (pNPs) comprised of polymerized antigen linked by poly(ethylene glycol) units are developed based on reactive electrospraying. This engineering approach allows fine tuning the physicoâchemical properties of pNPs such as particle size, elasticity, and mesh size. These properties are related to pNPs enhanced antigenâspecific immune responses and improved antiâtumor efficacy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163384/3/adtp202000100-sup-0001-SuppMat.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163384/2/adtp202000100.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163384/1/adtp202000100_am.pd
31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two
Background
The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd.
Methods
We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background.
Results
First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001).
Conclusions
In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival
Immunogenic Cell Death Amplified by Co-localized Adjuvant Delivery for Cancer Immunotherapy
Despite
their potential, conventional whole-cell cancer vaccines
prepared by freezeâthawing or irradiation have shown limited
therapeutic efficacy in clinical trials. Recent studies have indicated
that cancer cells treated with certain chemotherapeutics, such as
mitoxantrone, can undergo immunogenic cell death (ICD) and initiate
antitumor immune responses. However, it remains unclear how to exploit
ICD for cancer immunotherapy. Here, we present a new material-based
strategy for converting immunogenically dying tumor cells into a powerful
platform for cancer vaccination and demonstrate their therapeutic
potential in murine models of melanoma and colon carcinoma. We have
generated immunogenically dying tumor cells surface-modified with
adjuvant-loaded nanoparticles. Dying tumor cells laden with adjuvant
nanodepots efficiently promote activation and antigen cross-presentation
by dendritic cells in vitro and elicit robust antigen-specific CD8α<sup>+</sup> T-cells in vivo. Furthermore, whole tumor-cell vaccination
combined with immune checkpoint blockade leads to complete tumor regression
in âŒ78% of CT26 tumor-bearing mice and establishes long-term
immunity against tumor recurrence. Our strategy presented here may
open new doors to âpersonalizedâ cancer immunotherapy
tailored to individual patientâs tumor cells
Self-encapsulating Poly(lactic-<i>co</i>-glycolic acid) (PLGA) Microspheres for Intranasal Vaccine Delivery
Herein
we describe a formulation of self-encapsulating polyÂ(lactic-<i>co</i>-glycolic acid) (PLGA) microspheres for vaccine delivery.
Self-healing encapsulation is a novel encapsulation method developed
by our group that enables the aqueous loading of large molecules into
premade PLGA microspheres. Calcium phosphate (CaHPO<sub>4</sub>) adjuvant
gel was incorporated into the microspheres as a protein-trapping agent
for improved encapsulation of antigen. Microspheres were found to
have a median size of 7.05 ± 0.31 Όm, with a w/w loading
of 0.60 ± 0.05% of ovalbumin (OVA) model antigen. The formulation
demonstrated continuous release of OVA over a 49-day period. Released
OVA maintained its antigenicity over the measured period of >21
days
of release. C57BL/6 mice were immunized via the intranasal route with
prime and booster doses of OVA (10 ÎŒg) loaded into microspheres
or coadministered with cholera toxin B (CTB), the gold standard of
mucosal adjuvants. Microspheres generated a Th2-type response in both
serum and local mucosa, with IgG antibody responses approaching those
generated by CTB. The results suggest that this formulation of self-encapsulating
microspheres shows promise for further study as a vaccine delivery
system
Extracellular TrapâMimicking DNAâHistone Mesostructures Synergistically Activate Dendritic Cells
Extracellular traps (ETs), such as neutrophil extracellular traps, are a physical mesh deployed by immune cells to entrap and constrain pathogens. ETs are immunogenic structures composed of DNA, histones, and an array of variable protein and peptide components. While much attention has been paid to the multifaceted function of these structures, mechanistic studies of ETs remain challenging due to their heterogeneity and complexity. Here, a novel DNAâhistone mesostructure (DHM) formed by complexation of DNA and histones into a fibrous mesh is reported. DHMs mirror the DNAâhistone structural frame of ETs and offer a facile platform for cell culture studies. It is shown that DHMs are potent activators of dendritic cells and identify both the methylation state of DHMs and physical interaction between dendritic cells and DHMs as key tuning switches for immune stimulation. Overall, the DHM platform provides a new opportunity to study the role of ETs in immune activation and pathophysiology.A novel DNAâhistone mesostructure (DHM) platform is reported, which mirrors the morphology of extracellular traps (ETs). This platform enables bottomâup cellâbased assays to determine the role of the DNAâhistone substructure in ETâassociated phenomena. Here, DHMs are used to investigate ETâmediated immunostimulation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152974/1/adhm201900926.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152974/2/adhm201900926_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152974/3/adhm201900926-sup-0001-SuppMat.pd