Affinity of the alpha4–beta1 integrin-targeting peptide LLP2A to canine lymphoma

Abstract

Lymphoma is an important disease in dogs and people, with similar biological characteristics. We tested the binding affinity of a peptidomimetic LLP2A, previously shown to bind the alpha4–beta1 integrin on human lymphoma cell lines, to lymphocytes of dogs with spontaneously occurring lymphoma. Fine needle aspirates of lymph nodes from 32 dogs with B-cell lymphoma and 7 dogs with T-cell lymphoma were evaluated using flow cytometry. For B cells, the lowest MFI levels were in unlabeled, non-neoplastic lymphocytes. The highest median fluorescent intensity (MFI) levels occurred in LLP2A-labeled lymphoma cells from dogs that had not received chemotherapy followed by labeled lymphoma cells from dogs that had received chemotherapy. The fluorescence profile of the T-cell samples was similar although many of the differences were not statistically significant, likely due to low sample number. Specifically, LLP2A-labeled T-cell lymphoma cells had a significantly higher MFI compared to unlabeled non-neoplastic lymphocytes. LLP2A affinity was not significantly different in unlabeled and labeled T-cell lymphoma cells, and labeled non-neoplastic lymphocytes. For both B and T cells, labeling with LLP2A tended to increase MFI in both normal and lymphoma cells. Lymphoma cells had higher mean MFI levels than non-neoplastic lymphocytes, and chemotherapy acted to decrease MFI. In summary, these data demonstrate that LLP2A has affinity to canine lymphoma cells and indicates expression of the alpha4–beta1 integrin on these cells. In fact, LLP2A preferentially binds neoplastic B-cells, suggesting that this small molecule may be of use in cross-species clinical trials of targeted therapeutics.

Sensitizing B- and T- cell Lymphoma Cells to Paclitaxel/Abraxane–Induced Death by AS101 via Inhibition of the VLA-4–IL10–Survivin Axis

“…Indeed, we show here that the compound inhibits the activity of VLA-4 on lymphoma cells as expressed by inhibition of cell attachment to the VLA-4 ligand VCAM-1. The VLA-4 integrin has been recently found to be expressed on lymphoma cells (42). We show in this study that inactivation of VLA-4 mediates the inhibitory effect of AS101 on lymphoma IL10 production Specifically, our data imply that regulation of IL10 in lymphoma cells by AS101 is mediated by VLA-4 inactivation and the resulting decrease in pAkt.…”

Very Late Antigen-4 (α4β1 Integrin) Targeted PET Imaging of Multiple Myeloma

“…Cell uptake studies performed in the absence of receptor activating cations, in this case, Mn 2+ , resulted in much lower binding (data not shown). Lam and co-workers have also shown independently that LLP2A binds to the activated form of α 4 β 1 integrin [38], [42]. Additional studies will be needed to describe the changes in VLA-4 activation status in response to different stimuli [43].…”

“…LLP2A is comprised of D- and unnatural amino acids which makes it resistant to proteases in human plasma, and has been evaluated as a promising VLA-4 specific therapeutic agent that possesses safety features for potential human use [38]. The conjugate, CB-TE1A1P-LLP2A, can be labeled with Cu-64 in high specific activity under mild conditions [39].…”

Advances in Diagnostic and Treatment Modalities for Intracranial Tumors

“…Random screening of peptide libraries is an efficient method to define tumor‐specific peptides,224 and has been done for several canine cancers including lymphoma, melanoma, and glioma 130, 225, 226. Tumor‐specific targeting of glioma using peptides recognizing alpha 3 beta 1 integrin has been demonstrated in human cancers 227.…”