Limits...
In situ modulation of dendritic cells by injectable thermosensitive hydrogels for cancer vaccines in mice.

Liu Y, Xiao L, Joo KI, Hu B, Fang J, Wang P - Biomacromolecules (2014)

Bottom Line: Attempts to develop cell-based cancer vaccines have shown limited efficacy, partly because transplanted dendritic cells (DCs) do not survive long enough to reach the lymph nodes.We demonstrate that GM-CSF-releasing mPEG-PLGA hydrogels successfully recruit and house DCs and macrophages, allowing the subsequent introduction of antigens by vectors to activate the resident cells, thus, initiating antigen presentation and triggering immune response.This injectable thermosensitive hydrogel shows great promise as an adjuvant for cancer vaccines, potentially providing a new approach for cell therapies through in situ modulation of cells.

View Article: PubMed Central - PubMed

Affiliation: Mork Family Department of Chemical Engineering and Materials Science, ‡Department of Biomedical Engineering, and §Department of Pharmacology and Pharmaceutical Sciences, University of Southern California , Los Angeles, California 90089, United States.

ABSTRACT
Attempts to develop cell-based cancer vaccines have shown limited efficacy, partly because transplanted dendritic cells (DCs) do not survive long enough to reach the lymph nodes. The development of biomaterials capable of modulating DCs in situ to enhance antigen uptake and presentation has emerged as a novel method toward developing more efficient cancer vaccines. Here, we propose a two-step hybrid strategy to produce a more robust cell-based cancer vaccine in situ. First, a significant number of DCs are recruited to an injectable thermosensitive mPEG-PLGA hydrogel through sustained release of chemoattractants, in particular, granulocyte-macrophage colony-stimulating factor (GM-CSF). Then, these resident DCs can be loaded with cancer antigens through the use of viral or nonviral vectors. We demonstrate that GM-CSF-releasing mPEG-PLGA hydrogels successfully recruit and house DCs and macrophages, allowing the subsequent introduction of antigens by vectors to activate the resident cells, thus, initiating antigen presentation and triggering immune response. Moreover, this two-step hybrid strategy generates a high level of tumor-specific immunity, as demonstrated in both prophylactic and therapeutic models of murine melanoma. This injectable thermosensitive hydrogel shows great promise as an adjuvant for cancer vaccines, potentially providing a new approach for cell therapies through in situ modulation of cells.

Show MeSH

Related in: MedlinePlus

In vivorecruitment and migration of dendritic cells and macrophagesin response to hydrogels loaded with GM-CSF (5 μg). (A) Degradationof empty hydrogel (Emp-hydrogel) and hydrogel loaded with GM-CSF (GM-hydrogel)at various time points after injection. (B) Total number of cellscollected from Emp-hydrogel or GM-hydrogel at indicated time pointsafter injection (n = 3). (C) Histologic appearanceof Emp-hydrogel and GM-hydrogel with CD11c staining 7 days postinjection.(D, E) The number of CD11c+ DCs (D) and F4/80+ macrophages (E) recruited by GM-CSF-loaded hydrogel at indicatedtime points after injection. (F) Flow cytometric analysis of CD11c+CD86+, F4/80+CD86+, CCR7+CD11c+, and PDCA-1+CD11c+ cells from a representative mouse from each group 7 days after Emp-hydrogelor GM-hydrogel injection. (G) Representative images of hydrogel sectionsof mice stained for CD11c and F4/80, showing recruitment of DCs andmacrophages in GM-hydrogel 7 days postinjection. (H) GM-hydrogel increasesthe migration of DCs and macrophages to the draining LNs. Flow cytometricanalysis of CD11c+FITC+ cells and F4/80+FITC+ cells from a representative mouse from eachgroup 3 days after injection of FITC and MPL (as adjuvant).
© Copyright Policy - editor-choice
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4195289&req=5

fig2: In vivorecruitment and migration of dendritic cells and macrophagesin response to hydrogels loaded with GM-CSF (5 μg). (A) Degradationof empty hydrogel (Emp-hydrogel) and hydrogel loaded with GM-CSF (GM-hydrogel)at various time points after injection. (B) Total number of cellscollected from Emp-hydrogel or GM-hydrogel at indicated time pointsafter injection (n = 3). (C) Histologic appearanceof Emp-hydrogel and GM-hydrogel with CD11c staining 7 days postinjection.(D, E) The number of CD11c+ DCs (D) and F4/80+ macrophages (E) recruited by GM-CSF-loaded hydrogel at indicatedtime points after injection. (F) Flow cytometric analysis of CD11c+CD86+, F4/80+CD86+, CCR7+CD11c+, and PDCA-1+CD11c+ cells from a representative mouse from each group 7 days after Emp-hydrogelor GM-hydrogel injection. (G) Representative images of hydrogel sectionsof mice stained for CD11c and F4/80, showing recruitment of DCs andmacrophages in GM-hydrogel 7 days postinjection. (H) GM-hydrogel increasesthe migration of DCs and macrophages to the draining LNs. Flow cytometricanalysis of CD11c+FITC+ cells and F4/80+FITC+ cells from a representative mouse from eachgroup 3 days after injection of FITC and MPL (as adjuvant).

Mentions: Since it was shownthat the sustained release of GM-CSF from hydrogelssuccessfully attracts BMDCs and BMDMs, we next proposed that the diffusionof this factor through the surrounding tissue could effectively recruithost DCs and macrophages. To examine this hypothesis, C57BL/6J micewere injected once s.c. with hydrogels containing 5 μg of GM-CSFor empty hydrogels. Implanted materials were collected from each groupat days 3, 7, 14, or 21 postinjection to either count the number ofrecruited cells or to identify recruited cell types by FACS and histologyassay. As shown in Figure 2A, some yellowishcolor and blood vessels were formed on the GM-CSF hydrogel-injectedarea, while the empty hydrogel maintained its clear appearance, indicatingthat cells were recruited around the GM-CSF hydrogels. The thermosensitivehydrogel decreased in size with the passage of time, indicating thatit is a biodegradable polymer. On day 7, the quantitative data (Figure 2B) show that the GM-CSF hydrogel recruited 3–4million cells, consisting of ∼0.5 million CD11c+ DCs, as shown in Figure 2D. Histology examinationof the hydrogels also showed a significant number of CD11c+ dendritic cells in the GM-CSF hydrogel-injected mice, indicatingthat GM-CSF from hydrogel retains its cell-recruiting function invivo. About 0.5 million F4/80+ macrophages also accumulatedaround the GM-CSF hydrogel (Figure 2E), suggestingthat sustained release of GM-CSF can recruit macrophages, as wellas DCs, in vivo. Analysis of DCs and macrophages specifically (CD11c+CD86+ and F4/80+CD86+, respectively)showed that GM-CSF increased not just the total resident cell number,but also the percentage of mature DCs and macrophages (Figure 2F). Importantly, it was shown that most recruitedDCs were inactive DCs (CCR7–CD11c+) andthat some portions of plasmacytoid DCs (PDCA+CD11c+) were also recruited. Immunofluorescent staining (Figure 2G) on the collected hydrogels further confirmedthe effects of GM-CSF encapsulation on in vivo DC and macrophage recruitment.


In situ modulation of dendritic cells by injectable thermosensitive hydrogels for cancer vaccines in mice.

Liu Y, Xiao L, Joo KI, Hu B, Fang J, Wang P - Biomacromolecules (2014)

In vivorecruitment and migration of dendritic cells and macrophagesin response to hydrogels loaded with GM-CSF (5 μg). (A) Degradationof empty hydrogel (Emp-hydrogel) and hydrogel loaded with GM-CSF (GM-hydrogel)at various time points after injection. (B) Total number of cellscollected from Emp-hydrogel or GM-hydrogel at indicated time pointsafter injection (n = 3). (C) Histologic appearanceof Emp-hydrogel and GM-hydrogel with CD11c staining 7 days postinjection.(D, E) The number of CD11c+ DCs (D) and F4/80+ macrophages (E) recruited by GM-CSF-loaded hydrogel at indicatedtime points after injection. (F) Flow cytometric analysis of CD11c+CD86+, F4/80+CD86+, CCR7+CD11c+, and PDCA-1+CD11c+ cells from a representative mouse from each group 7 days after Emp-hydrogelor GM-hydrogel injection. (G) Representative images of hydrogel sectionsof mice stained for CD11c and F4/80, showing recruitment of DCs andmacrophages in GM-hydrogel 7 days postinjection. (H) GM-hydrogel increasesthe migration of DCs and macrophages to the draining LNs. Flow cytometricanalysis of CD11c+FITC+ cells and F4/80+FITC+ cells from a representative mouse from eachgroup 3 days after injection of FITC and MPL (as adjuvant).
© Copyright Policy - editor-choice
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4195289&req=5

fig2: In vivorecruitment and migration of dendritic cells and macrophagesin response to hydrogels loaded with GM-CSF (5 μg). (A) Degradationof empty hydrogel (Emp-hydrogel) and hydrogel loaded with GM-CSF (GM-hydrogel)at various time points after injection. (B) Total number of cellscollected from Emp-hydrogel or GM-hydrogel at indicated time pointsafter injection (n = 3). (C) Histologic appearanceof Emp-hydrogel and GM-hydrogel with CD11c staining 7 days postinjection.(D, E) The number of CD11c+ DCs (D) and F4/80+ macrophages (E) recruited by GM-CSF-loaded hydrogel at indicatedtime points after injection. (F) Flow cytometric analysis of CD11c+CD86+, F4/80+CD86+, CCR7+CD11c+, and PDCA-1+CD11c+ cells from a representative mouse from each group 7 days after Emp-hydrogelor GM-hydrogel injection. (G) Representative images of hydrogel sectionsof mice stained for CD11c and F4/80, showing recruitment of DCs andmacrophages in GM-hydrogel 7 days postinjection. (H) GM-hydrogel increasesthe migration of DCs and macrophages to the draining LNs. Flow cytometricanalysis of CD11c+FITC+ cells and F4/80+FITC+ cells from a representative mouse from eachgroup 3 days after injection of FITC and MPL (as adjuvant).
Mentions: Since it was shownthat the sustained release of GM-CSF from hydrogelssuccessfully attracts BMDCs and BMDMs, we next proposed that the diffusionof this factor through the surrounding tissue could effectively recruithost DCs and macrophages. To examine this hypothesis, C57BL/6J micewere injected once s.c. with hydrogels containing 5 μg of GM-CSFor empty hydrogels. Implanted materials were collected from each groupat days 3, 7, 14, or 21 postinjection to either count the number ofrecruited cells or to identify recruited cell types by FACS and histologyassay. As shown in Figure 2A, some yellowishcolor and blood vessels were formed on the GM-CSF hydrogel-injectedarea, while the empty hydrogel maintained its clear appearance, indicatingthat cells were recruited around the GM-CSF hydrogels. The thermosensitivehydrogel decreased in size with the passage of time, indicating thatit is a biodegradable polymer. On day 7, the quantitative data (Figure 2B) show that the GM-CSF hydrogel recruited 3–4million cells, consisting of ∼0.5 million CD11c+ DCs, as shown in Figure 2D. Histology examinationof the hydrogels also showed a significant number of CD11c+ dendritic cells in the GM-CSF hydrogel-injected mice, indicatingthat GM-CSF from hydrogel retains its cell-recruiting function invivo. About 0.5 million F4/80+ macrophages also accumulatedaround the GM-CSF hydrogel (Figure 2E), suggestingthat sustained release of GM-CSF can recruit macrophages, as wellas DCs, in vivo. Analysis of DCs and macrophages specifically (CD11c+CD86+ and F4/80+CD86+, respectively)showed that GM-CSF increased not just the total resident cell number,but also the percentage of mature DCs and macrophages (Figure 2F). Importantly, it was shown that most recruitedDCs were inactive DCs (CCR7–CD11c+) andthat some portions of plasmacytoid DCs (PDCA+CD11c+) were also recruited. Immunofluorescent staining (Figure 2G) on the collected hydrogels further confirmedthe effects of GM-CSF encapsulation on in vivo DC and macrophage recruitment.

Bottom Line: Attempts to develop cell-based cancer vaccines have shown limited efficacy, partly because transplanted dendritic cells (DCs) do not survive long enough to reach the lymph nodes.We demonstrate that GM-CSF-releasing mPEG-PLGA hydrogels successfully recruit and house DCs and macrophages, allowing the subsequent introduction of antigens by vectors to activate the resident cells, thus, initiating antigen presentation and triggering immune response.This injectable thermosensitive hydrogel shows great promise as an adjuvant for cancer vaccines, potentially providing a new approach for cell therapies through in situ modulation of cells.

View Article: PubMed Central - PubMed

Affiliation: Mork Family Department of Chemical Engineering and Materials Science, ‡Department of Biomedical Engineering, and §Department of Pharmacology and Pharmaceutical Sciences, University of Southern California , Los Angeles, California 90089, United States.

ABSTRACT
Attempts to develop cell-based cancer vaccines have shown limited efficacy, partly because transplanted dendritic cells (DCs) do not survive long enough to reach the lymph nodes. The development of biomaterials capable of modulating DCs in situ to enhance antigen uptake and presentation has emerged as a novel method toward developing more efficient cancer vaccines. Here, we propose a two-step hybrid strategy to produce a more robust cell-based cancer vaccine in situ. First, a significant number of DCs are recruited to an injectable thermosensitive mPEG-PLGA hydrogel through sustained release of chemoattractants, in particular, granulocyte-macrophage colony-stimulating factor (GM-CSF). Then, these resident DCs can be loaded with cancer antigens through the use of viral or nonviral vectors. We demonstrate that GM-CSF-releasing mPEG-PLGA hydrogels successfully recruit and house DCs and macrophages, allowing the subsequent introduction of antigens by vectors to activate the resident cells, thus, initiating antigen presentation and triggering immune response. Moreover, this two-step hybrid strategy generates a high level of tumor-specific immunity, as demonstrated in both prophylactic and therapeutic models of murine melanoma. This injectable thermosensitive hydrogel shows great promise as an adjuvant for cancer vaccines, potentially providing a new approach for cell therapies through in situ modulation of cells.

Show MeSH
Related in: MedlinePlus