Effects of a human compact anti-ErbB2 antibody on gastric cancer

Systematic Analysis of Molecular Characterization and Clinical Relevance of Liquid–Liquid Phase Separation Regulators in Digestive System Neoplasms

Background: The role of liquid–liquid phase separation (LLPS) in cancer has also attracted more and more attention, which is found to affect transcriptional regulation, maintaining genomic stability and signal transduction, and contribute to the occurrence and progression of tumors. However, the role of LLPS in digestive system tumors is still largely unknown.

Results: Here, we characterized the expression profiles of LLPS regulators in 3 digestive tract tumor types such as COAD, STAD, and ESCA with The Cancer Genome Atlas (TCGA) data. Our results for the first time showed that LLPS regulatory factors, such as Brd4, FBN1, and TP53, were frequently mutated in all types of digestive system tumors. Variant allele frequency (VAF) and APOBEC analysis demonstrated that genetic alterations of LLPS regulators were related to the progression of digestive system neoplasms (DSNs), such as TP53, NPHS1, TNRC6B, ITSN1, TNPO1, PML, AR, BRD4, DLG4, and PTPN1. KM plotter analysis showed that the mutation status of LLPS regulators was significantly related to the overall survival (OS) time of DSNs, indicating that they may contribute to the progression of DSN. The expression analysis of LLPS regulatory factors showed that a variety of LLPS regulatory factors were significantly dysregulated in digestive system tumors, such as SYN2 and MAPT. It is worth noting that we first found that LLPS regulatory factors were significantly correlated with tumor immune infiltration of B cells, CD4+ T cells, and CD8+ T cells in digestive system tumors. Bioinformatics analysis showed that the LLPS regulators’ expression was closely related to multiple signaling, including the ErbB signaling pathway and T-cell receptor signaling pathway. Finally, several LLPS signatures were constructed and had a strong prognostic stratification ability in different digestive gland tumors. Finally, the results demonstrated the LLPS regulators’ signature score was significantly positively related to the infiltration levels of CD4⁺ T cells, neutrophil cells, macrophage cells, and CD8⁺ T cells.

Conclusion: Our study for the first time showed the potential roles of LLPS regulators in carcinogenesis and provide novel insights to identify novel biomarkers for the prediction of immune therapy and prognosis of DSNs.

T-cell Activating Tribodies as a Novel Approach for Efficient Killing of ErbB2-positive Cancer Cells

The Tyrosine Kinase Receptor ErbB2 (HER2) when overexpressed in breast cancer (BC) is associated with poor prognosis. The monoclonal antibody Trastuzumab has become a standard treatment of ErbB2+BC. The antibody treatment has limited efficacy, often meets resistance and induces cardiotoxicity. T-cell recruiting bispecific antibody derivatives (TRBA) offer a more effective alternative to standard antibody therapy. We evaluated a panel of TRBAs targeting 3 different epitopes on the ErbB2 receptor either in a bivalent targeting tribody structure or as a monovalent scFv-fusion (BiTE format) for binding, cytotoxicity on Trastuzumab-resistant cell lines, and induction of cardiotoxicity. All three TRBAs bind with high affinity to the ErbB2 extracellular domain and a large panel of ErbB2-positive tumor cells. Tribodies had an increased in vitro cytotoxic potency as compared to BiTEs. It is interesting to note that, Tribodies targeting the epitopes on ErbB2 receptor domains I and II bind and activate lysis of mammary and gastric tumor cells more efficiently than a Tribody targeting the Trastuzumab epitope on domain IV. The first 2 are also active on Trastuzumab-resistant cancer cells lacking or masking the epitope recognized by Trastuzumab. None of the Tribodies studied showed significant toxicity on human cardiomyocytes. Altogether these results make these novel anti-ErbB2 bispecific Tribodies candidates for therapeutic development for treating ErbB2-positive Trastuzumab-resistant cancer patients.

Novel Human Bispecific Aptamer-Antibody Conjugates for Efficient Cancer Cell Killing

Monoclonal antibodies have been approved by the Food and Drug Administration for the treatment of various human cancers. More recently, oligonucleotide aptamers have risen increasing attention for cancer therapy thanks to their low size (efficient tumor penetration) and lack of immunogenicity, even though the short half-life and lack of effector functions still hinder their clinical applications. Here, we demonstrate, for the first time, that two novel bispecific conjugates, consisting of an anti-epidermal growth factor receptor (EGFR) aptamer linked either with an anti-epidermal growth factor receptor 2 (ErbB2) compact antibody or with an immunomodulatory (anti-PD-L1) antibody, were easily and rapidly obtained. These novel aptamer-antibody conjugates retain the targeting ability of both the parental moieties and acquire a more potent cancer cell killing activity by combining their inhibitory properties. Furthermore, the conjugation of the anti-EGFR aptamer with the immunomodulatory antibody allowed for the efficient redirection and activation of T cells against cancer cells, thus dramatically enhancing the cytotoxicity of the two conjugated partners. We think that these bispecific antibody-aptamer conjugates could have optimal biological features for therapeutic applications, such as increased specificity for tumor cells expressing both targets and improved pharmacokinetic and pharmacodynamic properties due to the combined advantages of the aptamer and antibody.

Cardiotoxic effects of the novel approved anti-ErbB2 agents and reverse cardioprotective effects of ranolazine

Purpose

Pertuzumab, a novel anti-epidermal growth factor receptor 2 humanized monoclonal antibody, and trastuzumab-emtansine (TDM1), a novel antibody-drug conjugate made up of trastuzumab covalently linked to the highly potent microtubule inhibitory agent DM1, have been recently approved by the US Food and Drug Administration for increasing the efficiency and safety of breast cancer therapy with trastuzumab. We investigated for the first time the potential cardiotoxic effects of pertuzumab and TDM1, which are not yet fully elucidated, and we tested whether ranolazine could blunt their cardiotoxicity.

Methods

The cardiotoxic effects were tested in vitro on rat cardiomyoblasts, human fetal cardiomyocytes, adult-like cardiomyocytes, and in vivo on a mouse model.

Results

All the treated cardiac cell lines were significantly affected by treatment with the tested drugs. Surprisingly, TDM1 showed stronger inhibitory effects on cardiac cells with respect to trastuzumab and pertuzumab by more significantly reducing the cell viability and by changing the morphology of these cells. TDM1 also affected the beating phenotype of adult-like cardiomyocytes in vitro and reduced fractional shortening and ejection fraction in vivo in a mouse model. We also found that ranolazine attenuated not only the cardiotoxic side effects of trastuzumab but also those of pertuzumab and TDM1, when used in combinatorial treatments both in vitro and in vivo, as demonstrated by the recovery of fractional shortening and ejection fraction values in mice pretreated with TDM1.

Conclusion

We demonstrated that it is possible to predict the eventual cardiotoxic effects of novel approved anticancer drugs early by using in vitro and in vivo approaches, which can also be useful to screen in advance the cardioprotective agents, so as to avoid the onset of unwanted cardiotoxic side effects.

Detection of autoantibodies against carbonic anhydrase I and II in the plasma of patients with gastric cancer

Cancer is the second leading cause of death and gastric cancer is the fourth most common cancer type worldwide. Investigation of autoantibodies in cancer patients has been a popular research area in recent years. The aim of the current study was to investigate carbonic anhydrase I and II (CA I and II) autoantibodies in the plasma of subjects with gastric cancer based on the information and considerations of autoimmune relation of gastric cancer. Anti-CA I and II antibody levels were investigated by ELISA in plasma samples of fifty two patients with gastric cancer and thirty five healthy peers. Anti-CA I and II antibody titers of the gastric cancer group were significantly higher compared with the control group (p = 0.004, p = 0.0001, respectively). Plasma anti-CA I levels of the metastatic group were lower than the non-metastatic group and this difference was found statistically significant (p < 0.05), but there was no statistical difference between plasma anti-CA II levels of the groups. CA I and II autoantibody titers in patients with gastric cancer were found higher compared to healthy subjects and the results suggest that these autoantibodies may be involved in the pathogenesis of gastric cancer.

Effects of a second-generation human anti-ErbB2 ImmunoRNase on trastuzumab-resistant tumors and cardiac cells

The inhibition of ErbB2 by the use of human antibodies can be a valuable strategy for the treatment of breast and gastric cancer. Trastuzumab, a humanized anti-ErbB2 antibody in clinical use, is effective but can engender resistance as well as cardiotoxicity. ImmunoRNases, made up of a human anti-ErbB2 scFv and human pancreatic ribonucleases (HP-RNases), have been engineered to overcome the limits of other immunotoxins, such as immunogenicity and nonspecific toxicity. Here, we report that a novel anti-ErbB2 immunoRNase, called Erb-HPDDADD-RNase, obtained by fusing Erbicin, a human ErbB2-directed scFv, with an HP-RNase variant that resists the cytosolic inhibitor protein, binds with high affinity to a panel of ErbB2-positive gastric tumor cells and inhibits their growth more than does the parental immunoRNase, which is not resistant to the inhibitor. Moreover, Erb-HP-DDADD-RNase is endowed with antiproliferative activity for trastuzumab-resistant cancer cells both in vitro and in vivo that is more potent than that of the parental immunoRNase. Importantly, Erb-HP-DDADD-RNase does not show cardiotoxic effects in vitro on human cardiomyocytes and does not impair cardiac function in a mouse model. Thus, Erb-HP-DDADD-RNase could fulfil the therapeutic need of cancer patients ineligible for trastuzumab treatment due to primary or acquired trastuzumab resistance or to cardiac dysfunction.