HER2/ERBB2 immunoreactivity in human retinoblastoma

Optimizing CARs for ocular delivery

Effective methods for treating retinoblastoma while preserving vision are an unmet clinical need. Subretinal delivery of a hydrogel containing T cells that secrete the cytokine IL-15 and express a chimeric antigen receptor directed at the ganglioside protein GD2 completely controls retinoblastoma in immunocompromised mice, with no obvious damage to the surrounding retina.

In situ analysis of Her2 DNA and RNA in retinoblastoma and adjacent retina

Retinoblastoma (RB) is an ocular tumor of early childhood. Current treatments attempt to preserve visual function, but may spare chemoresistant tumor cells. One potential therapeutic target for RB is HER2, (ERBB2), expressed in RB in truncated form. In this study, we tested the hypothesis that Her2 DNA and RNA are expressed in RB tumors and adjacent retina. We examined 24 human RB tumors as well as normal-appearing adjacent retinal tissues for Her2 DNA and RNA expression by in situ hybridization. We also examined 28 RB tumors for HER2 protein immunoreactivity. 21/22 RB tumors expressed Her2 DNA and 14/19 tumors expressed Her2 RNA. In 17 paired cases, there were three cases in which Her2 DNA was detected, but not RNA. We also saw Her2 RNA signal in six instances of "normal" adjacent retinal tissue. Heterogeneous HER2 protein expression in specific tumor regions also was confirmed by quantitative HER2 immunohistochemistry. In summary, Her2 DNA and RNA are expressed in many RB tumors, and in some adjacent ocular tissues, with hetereogenous protein expression throughout. These results may provide important insights regarding RB tumor progression, and drug targeting approaches designed to spare the eye, preserve vision and improve quality of life for RB patients.

Elimination of Osteosarcoma by Necroptosis with Graphene Oxide-Associated Anti-HER2 Antibodies

The prognosis for non-resectable or recurrent osteosarcoma (OS) remains poor. The finding that the majority of OS overexpress the protooncogene HER2 raises the possibility of using HER2 as a therapeutic target. However, clinical trials on the anti-HER2 antibody trastuzumab (TRA) in treating OS find no therapeutic benefit. HER2 overexpression in OS is not generally associated with gene amplification, with low-level expression regarded as HER2 “negative”, as per criteria used to classify breast cancer HER2 status. Nevertheless, active HER2-targeting approaches, such as virus-based HER2 vaccines or CAR-T cells have generated promising results. More recently, it has been found that the noncovalent association of TRA with nanomaterial graphene oxide (GO) generates stable TRA/GO complexes capable of rapidly killing OS cells. TRA/GO induces oxidative stress and strong HER2 signaling to elicit immediate degradation of both cIAP (cellular inhibitor of apoptosis protein) and caspase 8, leading to activation of necroptosis. This is an attractive mechanism of cancer cell death as chemo/apoptosis-resistant tumors may remain susceptible to necroptosis. In addition, necroptosis is potentially immunogenic to promote tumor immunity, as opposed to apoptosis that tends to silence tumor immunity. Currently, no established anticancer therapeutics are known to eliminate cancers by necroptosis. The aim of this article is to review the rationale and mechanisms of TRA/GO-mediated cytotoxicity.

Targeting tyrosine kinases for treatment of ocular tumors

Uveal melanoma is the most common intraocular primary malignant tumor in adults, and retinoblastoma is the one in children. Current mainstay treatment options include chemotherapy using conventional drugs and enucleation, the total removal of the eyeball. Targeted therapies based on profound understanding of molecular mechanisms of ocular tumors may increase the possibility of preserving the eyeball and the vision. Tyrosine kinases, which modulate signaling pathways regarding various cellular functions including proliferation, differentiation, and attachment, are one of the attractive targets for targeted therapies against uveal melanoma and retinoblastoma. In this review, the roles of both types of tyrosine kinases, receptor tyrosine kinases and non-receptor tyrosine kinases, were summarized in relation with ocular tumors. Although the conventional treatment options for uveal melanoma and retinoblastoma are radiotherapy and chemotherapy, respectively, specific tyrosine kinase inhibitors will enhance our armamentarium against them by controlling cancer-associated signaling pathways related to tyrosine kinases. This review can be a stepping stone for widening treatment options and realizing targeted therapies against uveal melanoma and retinoblastoma.

HER2 Overexpression in Retinoblastoma: A Potential Therapeutic Target?

Background

Retinoblastoma (RB) is the most common primary intraocular malignancy. Current therapies are associated with high morbidity in the short- and long-term. Human epidermal growth factor receptor 2 (HER2) is a transmembrane protein detected in 15-30% of breast cancers, but it has also been described in other malignancies. Recently, it has been claimed that a truncated version of this protein is expressed in RB, responsive to directed therapies in vitro. We scored HER2 overexpression in RB tissue samples and discussed its potential clinical utility.

Methods

HER2 overexpression was investigated using immunohistochemistry; the overexpression was evaluated with a score ranging from 0 to 3+ according to the membranous staining pattern in archival formalin-fixed, paraffin-embedded RBs.

Results

A total of 60 RB cases and a RB cell line (Y79) were considered. The mean age at enucleation was 31.6 ± 31.5 months. The mean time from diagnosis to enucleation was 11.8 ± 11.2 months (range 1-44). Five (8%) cases were multifocal. HER2 overexpression was negative in all RB cases (49 cases scored 0 and 11 scored 1+) and in the Y79 cell line.

Conclusions

Overall, we were not able to demonstrate the overexpression of HER2. Further studies should clarify and better elucidate the potential role of HER2-targeted therapies in RB.

BANCR: a cancer-related long non-coding RNA

Long non-coding RNAs (lncRNAs) are a group of non-protein-coding RNAs with more than 200 nucleotides in length. lncRNAs are involved in diverse biological processes, including development, cell proliferation and differentiation. Emerging evidences also suggest that lncRNAs may participate in cancer development by functioning as tumor suppressors and oncogenes. BRAF-activated non-coding RNA (BANCR) was first identified as an oncogene in melanoma. Later studies demonstrated that BANCR was frequently deregulated in human cancers, including lung cancer, gastric cancer, colorectal cancer, thyroid cancer and osteosarcoma. Nevertheless, the direction of deregulation was tissue-specific in which BANCR could as an oncogene or tumor-suppressor gene. In this review, we compile current evidences concerning the functional roles and molecular mechanisms of BANCR in tumor development.

ErbB Proteins as Molecular Target of Dietary Phytochemicals in Malignant Diseases

ErbB proteins overexpression, in both normal and mutated forms, is associated with invasive forms of cancer prone to metastasis and with stronger antiapoptotic mechanisms and therefore more challenging to treat. Downstream effectors of ErbB receptors mediating these phenotypic traits include MAPK, STAT, and PI3K/AKT/mTOR pathways. Various phytochemical compounds were studied for their large number of biological effects including anticancer activity. Among these compounds, epigallocatechin-3-gallate (EGCG), the main catechin from green tea leaves, and curcumin, component of the curry powder, constituted the object of numerous studies. Both compounds were shown to act directly either on ErbB expression, or on their downstream signaling molecules. In this paper we aim to review the involvement of ErbB proteins in cancer as well as the biologic activity of EGCG and curcumin in ErbB expressing and overexpressing malignancies. The problems arising in the administration of the two compounds due to their reduced bioavailability when orally administered, as well as the progress made in this field, from using novel formulations to improved dosing regimens or improved synthetic analogs, are also discussed.