Background: Glypican-3 (GPC-3) is an oncofetal protein that is highly expressed in various solid tumors, but rarely expressed in healthy adult tissues and represents a rational target of particular relevance in hepatocellular carcinoma (HCC). Autologous chimeric antigen receptor (CAR) αβ T cell therapies have established significant clinical benefit in hematologic malignancies, although efficacy in solid tumors has been limited due to several challenges including T cell homing, target antigen heterogeneity, and immunosuppressive tumor microenvironments. Gamma delta (γδ) T cells are highly cytolytic effectors that can recognize and kill tumor cells through major histocompatibility complex (MHC)-independent antigens upregulated under stress. The Vδ1 subset is preferentially localized in peripheral tissue and engineering with CARs to further enhance intrinsic antitumor activity represents an attractive approach to overcome challenges for conventional T cell therapies in solid tumors. Allogeneic Vδ1 CAR T cell therapy may also overcome other hurdles faced by allogeneic αβ T cell therapy, including graft-versus-host disease (GvHD).
Methods: We developed the first example of allogeneic CAR Vδ1 T cells that have been expanded from peripheral blood mononuclear cells (PBMCs) and genetically modified to express a 4-1BB/CD3z CAR against GPC-3. The CAR construct (GPC-3.CAR/secreted interleukin-15 (sIL)-15) additionally encodes a constitutively-secreted form of IL-15, which we hypothesized could sustain proliferation and antitumor activity of intratumoral Vδ1 T cells expressing GPC-3.CAR.
Results: GPC-3.CAR/sIL-15 Vδ1 T cells expanded from PBMCs on average 20,000-fold and routinely reached >80% purity. Expanded Vδ1 T cells showed a primarily naïve-like memory phenotype with limited exhaustion marker expression and displayed robust in vitro proliferation, cytokine production, and cytotoxic activity against HCC cell lines expressing low (PLC/PRF/5) and high (HepG2) GPC-3 levels. In a subcutaneous HepG2 mouse model in immunodeficient NSG mice, GPC-3.CAR/sIL-15 Vδ1 T cells primarily accumulated and proliferated in the tumor, and a single dose efficiently controlled tumor growth without evidence of xenogeneic GvHD. Importantly, compared with GPC-3.CAR Vδ1 T cells lacking sIL-15, GPC-3.CAR/sIL-15 Vδ1 T cells displayed greater proliferation and resulted in enhanced therapeutic activity.
Conclusions: Expanded Vδ1 T cells engineered with a GPC-3 CAR and sIL-15 represent a promising platform warranting further clinical evaluation as an off-the-shelf treatment of HCC and potentially other GPC-3-expressing solid tumors.
Background: One of the most often used complementary or alternative anticancer therapeutics for breast cancer is mistletoe extract with Viscum album lectin (VAA-1) as the leading component. The aim of this study was to determine the correlation between VAA-1 binding in breast cancer and disease outcome.
Materials And Methods: VAA-1 binding to either tumour cells or tumour infiltrating inflammatory cells was examined by immunohistochemical staining of paraffin tissue sections from breast cancer patients (n=226).
Background: Viscum album agglutinin-1 (VAA-1) is assumed to be the biologically most active ingredient of misteltoe extracts that are often used as adjuvant cancer therapy. To develop new approaches for lung cancer treatment, we evaluated the antineoplastic activity of VAA-1 alone and in combination with other chemotherapeutic drugs, including doxorubicin, cisplatin and taxol in the human lung carcinoma cell line A549.
Materials And Methods: Cytotoxicity was determined by 5-bromo-2'-deoxyuridine (BrdU) ELISA-assays and drug interaction assessed by the isobologram method.
The galactoside-specific lectin (mistletoe lectin-1, VAA-1) and the N-acetylgalactosamine-specific lectin (mistletoe lectin-2, VAA-2) were purified from aqueous mistletoe extract and checked for their immunoactive potency. Regular subcutaneous administration of the optimal immunomodulating VAA-1 /VAA-2 dosage (1 ng lectin/kg body weight) could be shown to modulate thymocyte proliferation, maturation, emigration and activation in BALB/c-mice. Thus, the increase in thymocyte counts was statistically significant after VAA-1 treatment.
