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Overcoming resistance to HER2-targeted therapy with a novel HER2/CD3 bispecific antibody

View Article: PubMed Central - PubMed

ABSTRACT

T-cell-based therapies have emerged as one of the most clinically effective ways to target solid and non-solid tumors. HER2 is responsible for the oncogenesis and treatment resistance of several human solid tumors. As a member of the HER family of tyrosine kinase receptors, its over-activity confers unfavorable clinical outcome. Targeted therapies directed at this receptor have achieved responses, although development of resistance is common. We explored a novel HER2/CD3 bispecific antibody (HER2-BsAb) platform that while preserving the anti-proliferative effects of trastuzumab, it recruits and activates non-specific circulating T-cells, promoting T cell tumor infiltration and ablating HER2(+) tumors, even when these are resistant to standard HER2-targeted therapies. Its in vitro tumor cytotoxicity, when expressed as EC50, correlated with the surface HER2 expression in a large panel of human tumor cell lines, irrespective of lineage or tumor type. HER2-BsAb-mediated cytotoxicity was relatively insensitive to PD-1/PD-L1 immune checkpoint inhibition. In four separate humanized mouse models of human breast cancer and ovarian cancer cell line xenografts, as well as human breast cancer and gastric cancer patient-derived xenografts (PDXs), HER2-BsAb was highly effective in promoting T cell infiltration and suppressing tumor growth when used in the presence of human peripheral blood mononuclear cells (PBMC) or activated T cells (ATC). The in vivo and in vitro antitumor properties of this BsAb support its further clinical development as a cancer immunotherapeutic.

No MeSH data available.


Related in: MedlinePlus

In vitro characterization of HER2-BsAb. (A) HER2-BsAb has the same specificity as trastuzumab. Pre-Incubation of the HER2(+)high SKOV3 cells with trastuzumab prevents HER2-BsAb binding. (B) HER2-BsAb and trastuzumab have similar avidity for SKOV3 cells. MFI was plotted against the antibody concentration. (C) HER2-BsAb maintained same anti-proliferative effects as trastuzumab against the trastuzumab-sensitive SKBR3 cells. (D) HER2-BsAb mediates T cell cytotoxicity against the HER2(+)MCF-7 cells but not the HER2(−) HTB-132 cells. (E) Blocking of HER2 or CD3 by trastuzumab or huOKT3, abrogates HER2-BsAb T-cell cytotoxicity. HER2(+) SCCHN PCI-13 cells were used in the cytotoxicity assay. For this experiment, 0.1 ug/mL of HER2-BsAb with 10 ug/mL of the blocking antibodies was used.
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f0001: In vitro characterization of HER2-BsAb. (A) HER2-BsAb has the same specificity as trastuzumab. Pre-Incubation of the HER2(+)high SKOV3 cells with trastuzumab prevents HER2-BsAb binding. (B) HER2-BsAb and trastuzumab have similar avidity for SKOV3 cells. MFI was plotted against the antibody concentration. (C) HER2-BsAb maintained same anti-proliferative effects as trastuzumab against the trastuzumab-sensitive SKBR3 cells. (D) HER2-BsAb mediates T cell cytotoxicity against the HER2(+)MCF-7 cells but not the HER2(−) HTB-132 cells. (E) Blocking of HER2 or CD3 by trastuzumab or huOKT3, abrogates HER2-BsAb T-cell cytotoxicity. HER2(+) SCCHN PCI-13 cells were used in the cytotoxicity assay. For this experiment, 0.1 ug/mL of HER2-BsAb with 10 ug/mL of the blocking antibodies was used.

Mentions: To determine if HER2-BsAb retained the specificity of trastuzumab, the HER2(+)high SKOV3 ovarian carcinoma cell line was pre-incubated with 10 µg/mL of trastuzumab for 30 min and then immunostained using 1 µg/mL HER2-BsAb labeled with Alexa 488 (Fig. 1A). Pre-incubation with trastuzumab prevented HER2-BsAb binding to SKOV3 cells, demonstrating that these antibodies shared the same specificity. To compare the avidity of HER2-BsAb to trastuzumab, the same cell line was incubated with 10-fold downward dilutions (from 10 µg/mL to 1 × 10−5 µg/mL) of trastuzumab or HER2-BsAb and analyzed by flow cytometry. The mean fluorescence intensity (MFI) was plotted against the antibody concentration in µM. Again the similarity in the binding curves confirmed that trastuzumab and HER2-BsAb had similar binding avidities for their common HER2 target (Fig. 1B).Figure 1.


Overcoming resistance to HER2-targeted therapy with a novel HER2/CD3 bispecific antibody
In vitro characterization of HER2-BsAb. (A) HER2-BsAb has the same specificity as trastuzumab. Pre-Incubation of the HER2(+)high SKOV3 cells with trastuzumab prevents HER2-BsAb binding. (B) HER2-BsAb and trastuzumab have similar avidity for SKOV3 cells. MFI was plotted against the antibody concentration. (C) HER2-BsAb maintained same anti-proliferative effects as trastuzumab against the trastuzumab-sensitive SKBR3 cells. (D) HER2-BsAb mediates T cell cytotoxicity against the HER2(+)MCF-7 cells but not the HER2(−) HTB-132 cells. (E) Blocking of HER2 or CD3 by trastuzumab or huOKT3, abrogates HER2-BsAb T-cell cytotoxicity. HER2(+) SCCHN PCI-13 cells were used in the cytotoxicity assay. For this experiment, 0.1 ug/mL of HER2-BsAb with 10 ug/mL of the blocking antibodies was used.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5384386&req=5

f0001: In vitro characterization of HER2-BsAb. (A) HER2-BsAb has the same specificity as trastuzumab. Pre-Incubation of the HER2(+)high SKOV3 cells with trastuzumab prevents HER2-BsAb binding. (B) HER2-BsAb and trastuzumab have similar avidity for SKOV3 cells. MFI was plotted against the antibody concentration. (C) HER2-BsAb maintained same anti-proliferative effects as trastuzumab against the trastuzumab-sensitive SKBR3 cells. (D) HER2-BsAb mediates T cell cytotoxicity against the HER2(+)MCF-7 cells but not the HER2(−) HTB-132 cells. (E) Blocking of HER2 or CD3 by trastuzumab or huOKT3, abrogates HER2-BsAb T-cell cytotoxicity. HER2(+) SCCHN PCI-13 cells were used in the cytotoxicity assay. For this experiment, 0.1 ug/mL of HER2-BsAb with 10 ug/mL of the blocking antibodies was used.
Mentions: To determine if HER2-BsAb retained the specificity of trastuzumab, the HER2(+)high SKOV3 ovarian carcinoma cell line was pre-incubated with 10 µg/mL of trastuzumab for 30 min and then immunostained using 1 µg/mL HER2-BsAb labeled with Alexa 488 (Fig. 1A). Pre-incubation with trastuzumab prevented HER2-BsAb binding to SKOV3 cells, demonstrating that these antibodies shared the same specificity. To compare the avidity of HER2-BsAb to trastuzumab, the same cell line was incubated with 10-fold downward dilutions (from 10 µg/mL to 1 × 10−5 µg/mL) of trastuzumab or HER2-BsAb and analyzed by flow cytometry. The mean fluorescence intensity (MFI) was plotted against the antibody concentration in µM. Again the similarity in the binding curves confirmed that trastuzumab and HER2-BsAb had similar binding avidities for their common HER2 target (Fig. 1B).Figure 1.

View Article: PubMed Central - PubMed

ABSTRACT

T-cell-based therapies have emerged as one of the most clinically effective ways to target solid and non-solid tumors. HER2 is responsible for the oncogenesis and treatment resistance of several human solid tumors. As a member of the HER family of tyrosine kinase receptors, its over-activity confers unfavorable clinical outcome. Targeted therapies directed at this receptor have achieved responses, although development of resistance is common. We explored a novel HER2/CD3 bispecific antibody (HER2-BsAb) platform that while preserving the anti-proliferative effects of trastuzumab, it recruits and activates non-specific circulating T-cells, promoting T cell tumor infiltration and ablating HER2(+) tumors, even when these are resistant to standard HER2-targeted therapies. Its in vitro tumor cytotoxicity, when expressed as EC50, correlated with the surface HER2 expression in a large panel of human tumor cell lines, irrespective of lineage or tumor type. HER2-BsAb-mediated cytotoxicity was relatively insensitive to PD-1/PD-L1 immune checkpoint inhibition. In four separate humanized mouse models of human breast cancer and ovarian cancer cell line xenografts, as well as human breast cancer and gastric cancer patient-derived xenografts (PDXs), HER2-BsAb was highly effective in promoting T cell infiltration and suppressing tumor growth when used in the presence of human peripheral blood mononuclear cells (PBMC) or activated T cells (ATC). The in vivo and in vitro antitumor properties of this BsAb support its further clinical development as a cancer immunotherapeutic.

No MeSH data available.


Related in: MedlinePlus