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Targeting proteins that are overexpressed in cancer cells is the major strategy of molecular imaging and drug delivery systems. The 67-kDa laminin receptor (67LR), also known as oncofetal antigen, is overexpressed in several types of cancer, including melanoma, multiple myeloma, cervical cancer and bile duct carcinoma. 67LR is involved in tumour growth, tumour metastasis and drug resistance. Green tea polyphenol (-)-epigallocatechin-3-O-gallate (EGCG) directly binds to cell-surface 67LR and induces apoptosis through the protein kinase B (Akt)/endothelial nitric oxide synthase/nitric oxide/cyclic GMP (cGMP) axis. Here we report the optimum hydroxyl group for the utilization of EGCG as a novel fluorescent EGCG-mimic imaging probe based on 67LR agonist characters, including Akt activation and inhibitory effect on viable cell number in cancer cells. 67LR specific targeting is unambiguously confirmed with the use of a non-labelled EGCG competitive assay and 67LR knockdown. Importantly, this probe strongly binds to multiple myeloma cells compared with its binding to normal cells.

Abnormal structural and molecular changes in malignant tissues were thoroughly investigated and utilized to target tumor cells, hence rescuing normal healthy tissues and lowering the unwanted side effects as non-specific cytotoxicity. Various ligands for cancer cell specific markers have been uncovered and inspected for directional delivery of the anti-cancer drug to the tumor site, in addition to diagnostic applications. Over the past few decades research related to the ligand targeted therapy (LTT) increased tremendously aiming to treat various pathologies, mainly cancers with well exclusive markers. Malignant tumors are known to induce elevated levels of a variety of proteins and peptides known as cancer "markers" as certain antigens (e.g., Prostate specific membrane antigen "PSMA", carcinoembryonic antigen "CEA"), receptors (folate receptor, somatostatin receptor), integrins (Integrin alpha v beta 3) and cluster of differentiation molecules (CD13). The choice of an appropriate marker to be targeted and the design of effective ligand-drug conjugate all has to be carefully selected to generate the required therapeutic effect. Moreover, since some tumors express aberrantly high levels of more than one marker, some approaches investigated targeting cancer cells with more than one ligand (dual or multi targeting). We aim in this review to report an update on the cancer-specific receptors and the vehicles to deliver cytotoxic drugs, including recent advancements on nano delivery systems and their implementation in targeted cancer therapy. We will discuss the advantages and limitations facing this approach and possible solutions to mitigate these obstacles. To achieve the said aim a literature search in electronic data bases (PubMed and others) using keywords "Cancer specific receptors, cancer specific antibody, tumor specific peptide carriers, cancer overexpressed proteins, gold nanotechnology and gold nanoparticles in cancer treatment" was carried out.

Abnormal structural and molecular changes in malignant tissues were thoroughly investigated and utilized to target tumor cells, hence rescuing normal healthy tissues and lowering the unwanted side effects as non-specific cytotoxicity. Various ligands for cancer cell specific markers have been uncovered and inspected for directional delivery of the anti-cancer drug to the tumor site, in addition to diagnostic applications. Over the past few decades research related to the ligand targeted therapy (LTT) increased tremendously aiming to treat various pathologies, mainly cancers with well exclusive markers. Malignant tumors are known to induce elevated levels of a variety of proteins and peptides known as cancer "markers" as certain antigens (e.g., Prostate specific membrane antigen "PSMA", carcinoembryonic antigen "CEA"), receptors (folate receptor, somatostatin receptor), integrins (Integrin alpha v beta 3) and cluster of differentiation molecules (CD13). The choice of an appropriate marker to be targeted and the design of effective ligand-drug conjugate all has to be carefully selected to generate the required therapeutic effect. Moreover, since some tumors express aberrantly high levels of more than one marker, some approaches investigated targeting cancer cells with more than one ligand (dual or multi targeting). We aim in this review to report an update on the cancer-specific receptors and the vehicles to deliver cytotoxic drugs, including recent advancements on nano delivery systems and their implementation in targeted cancer therapy. We will discuss the advantages and limitations facing this approach and possible solutions to mitigate these obstacles. To achieve the said aim a literature search in electronic data bases (PubMed and others) using keywords "Cancer specific receptors, cancer specific antibody, tumor specific peptide carriers, cancer overexpressed proteins, gold nanotechnology and gold nanoparticles in cancer treatment" was carried out.

Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is highly expressed in a wide variety of hematological and solid cancers, but is low or absent in adult tissues. Here, we show that ROR1 is released with exosomes from ROR1-positive cancer cells. We also developed a simple dissociation-enhanced lanthanide fluorescence immunoassay (DELFIA) to detect cancer-derived ROR1-positive exosomes, which are captured by two anti-ROR1 antibodies and detected by the fluorescence of free chelating europium. This new DELFIA method can detect cancer-derived ROR1-positive exosomes in the cell supernatant and serum with a wide range and rapidly compared with the conventional Western blot assay. This method may be useful as a companion diagnostics for ROR1-positive cancers.

After decades of cancer vaccine efforts, there is an imperious necessity for novel ideas that may result in better tumor control in patients. We have proposed the use of a novel Variable Epitope Library (VEL) vaccine strategy, which incorporates an unprecedented number of mutated epitopes to target antigenic variability and break tolerance against tumor-associated antigens. Here, we used an oncofetal antigen/immature laminin receptor protein-derived sequence to generate 9-mer and 43-mer VEL immunogens. 4T1 tumor-bearing mice developed epitope-specific CD8+IFN-γ+ and CD4+IFN-γ+ T cell responses after treatment. Tumor and lung analysis demonstrated that VELs could increase the number of tumor-infiltrating lymphocytes with diverse effector functions while reducing the number of immunosuppressive myeloid-derived suppressor and regulatory T cells. Most importantly, VEL immunogens inhibited tumor growth and metastasis after a single dose. The results presented here are consistent with our previous studies and provide evidence for VEL immunogens’ feasibility as promising cancer immunotherapy.

The 5T4 oncofetal antigen (trophoblast glycoprotein) is expressed in a wide range of malignant tumors but shows very limited expression in normal adult tissues. ASN004 is a 5T4-targeted antibody–drug conjugate (ADC) that incorporates a novel single-chain Fv-Fc antibody and Dolaflexin drug-linker technology, with an Auristatin F hydroxypropylamide payload drug-to-antibody ratio of approximately 10–12. The pharmacology, toxicology, and pharmacokinetic properties of ASN004 and its components were investigated in vitro and in vivo. ASN004 showed high affinity for the 5T4 antigen and was selectively bound to and internalized into 5T4-expressing tumor cells, and potent cytotoxicity was demonstrated for a diverse panel of solid tumor cell lines. ASN004 induced complete and durable tumor regression in multiple tumor xenograft models, derived from human lung, breast, cervical, and gastric tumor cell lines having a wide range of 5T4 expression levels. A single dose of ASN004, as low as 1 mg/kg i.v., achieved complete tumor regression leading to tumor-free survivors in the A431 cervical cancer model. In head-to-head studies, superior activity of ASN004 was demonstrated against trastuzumab-DM1, in a low-5T4/high-HER2 expressing gastric tumor model, and 10-fold greater potency was found for ASN004 against the 5T4-targeted ADC PF-06263507 in a lung tumor model. In marmoset monkeys, ASN004 was well tolerated at doses up to 1.5 mg/kg Q3W i.v., and showed dose-dependent exposure, linear pharmacokinetics, and markedly low exposure of free payload drug. Taken together, these findings identify ASN004 as a promising new ADC therapeutic for clinical evaluation in a broad range of solid tumor types.

Background Chimeric antigen receptors (CARs) are engineered synthetic receptors that reprogram T cell specificity and function against a given antigen. Autologous CAR-T cell therapy has demonstrated potent efficacy against various hematological malignancies, but has yielded limited success against solid cancers. MEDI7028 is a CAR that targets oncofetal antigen glypican-3 (GPC3), which is expressed in 70–90% of hepatocellular carcinoma (HCC), but not in normal liver tissue. Transforming growth factor β (TGFβ) secretion is increased in advanced HCC, which creates an immunosuppressive milieu and facilitates cancer progression and poor prognosis. We tested whether the anti-tumor efficacy of a GPC3 CAR-T can be enhanced with the co-expression of dominant-negative TGFβRII (TGFβRIIDN). Methods Primary human T cells were lentivirally transduced to express GPC3 CAR both with and without TGFβRIIDN. Western blot and flow cytometry were performed on purified CAR-T cells to assess modulation of pathways and immune phenotypes driven by TGFβ in vitro. A xenograft model of human HCC cell line overexpressing TGFβ in immunodeficient mice was used to investigate the in vivo efficacy of TGFβRIIDN armored and unarmored CAR-T. Tumor infiltrating lymphocyte populations were analyzed by flow cytometry while serum cytokine levels were quantified with ELISA. Results Armoring GPC3 CAR-T with TGFβRIIDN nearly abolished phospho-SMAD2/3 expression upon exposure to recombinant human TGFβ in vitro, indicating that the TGFβ signaling axis was successfully blocked by expression of the dominant-negative receptor. Additionally, expression of TGFβRIIDN suppressed TGFβ-driven CD103 upregulation, further demonstrating attenuation of the pathway by this armoring strategy. In vivo, the TGFβRIIDN armored CAR-T achieved superior tumor regression and delayed tumor regrowth compared to the unarmored CAR-T. The armored CAR-T cells infiltrated HCC tumors more abundantly than their unarmored counterparts, and were phenotypically less exhausted and less differentiated. In line with these observations, we detected significantly more interferon gamma (IFNγ) at peak response and decreased alpha-fetoprotein in the serum of mice treated with armored cells compared to mice receiving unarmored CAR-T, demonstrating in vivo functional superiority of TGFβRIIDN armored CAR-T therapy. Conclusions Armoring GPC3 CAR-T with TGFβRIIDN abrogates the signaling of TGFβ in vitro and enhances the anti-tumor efficacy of GPC3 CAR-T against TGFβ-expressing HCC tumors in vivo, proving TGFβRIIDN to be an effective armoring strategy against TGFβ-expressing solid malignancies in preclinical models. Ethics Approval The study was approved by AstraZeneca’s Ethics Board and Institutional Animal Care and Use Committee (IACUC).

Background Chimeric antigen receptor (CAR)-T therapy has yielded impressive clinical results in hematological malignancies and it is a promising approach for solid tumor treatment. However, toxicity, including on-target off-tumor antigen binding, is a concern hampering its broader use. Methods In selecting a lead CAR-T candidate against the oncofetal antigen glypican 3 (GPC3), we compared CAR bearing a low and high affinity single-chain variable fragment (scFv,) binding to the same epitope and cross-reactive with murine GPC3. We characterized low and high affinity CAR-T cells immunophenotype and effector function in vitro, followed by in vivo efficacy and safety studies in hepatocellular carcinoma (HCC) xenograft models. Results Compared to the high-affinity construct, the low-affinity CAR maintained cytotoxic function but did not show in vivo toxicity. High-affinity CAR-induced toxicity was caused by on-target off-tumor binding, based on the evidence that high-affinity but not low-affinity CAR, were toxic in non-tumor bearing mice and accumulated in organs with low expression of GPC3. To add another layer of safety, we developed a mean to target and eliminate CAR-T cells using anti-TNFα antibody therapy post-CAR-T infusion. This antibody functioned by eliminating early antigen-activated CAR-T cells, but not all CAR-T cells, allowing a margin where the toxic response could be effectively decoupled from anti-tumor efficacy. Conclusions Selecting a domain with higher off-rate improved the quality of the CAR-T cells by maintaining cytotoxic function while reducing cytokine production and activation upon antigen engagement. By exploring additional traits of the CAR-T cells post-activation, we further identified a mechanism whereby we could use approved therapeutics and apply them as an exogenous kill switch that would eliminate early activated CAR-T following antigen engagement in vivo. By combining the reduced affinity CAR with this exogenous control mechanism, we provide evidence that we can modulate and control CAR-mediated toxicity. Ethics Approval All animal experiments were conducted in a facility accredited by the Association for Assessment of Laboratory Animal Care (AALAC) under Institutional Animal Care and Use Committee (IACUC) guidelines and appropriate animal research approval.

Chimeric antigen receptor (CAR) T cells have revolutionized blood cancer immunotherapy; however, their efficacy against solid tumors has been limited. A common mechanism of tumor escape from single target therapies is downregulation or mutational loss of the nominal epitope. Targeting multiple antigens may thus improve the effectiveness of CAR immunotherapies. We generated dual CAR-T cells targeting two tumor antigens: TAG-72 (tumor-associated glycoprotein 72) and CD47. TAG-72 is a pan-adenocarcinoma oncofetal antigen, highly expressed in ovarian cancers, with increased expression linked to disease progression. CD47 is ubiquitously overexpressed in multiple tumor types, including ovarian cancer; it is a macrophage “don’t eat me” signal. However, CD47 is also expressed on many normal cells. To avoid this component of the dual CAR-T cells killing healthy tissue, we designed a truncated CD47 CAR devoid of intracellular signaling domains. The CD47 CAR facilitates binding to CD47+ cells, increasing the prospect of TAG-72+ cell elimination via the TAG-72 CAR. Furthermore, we could reduce the damage to normal tissue by monomerizing the CD47 CAR. Our results indicate that the co-expression of the TAG-72 CAR and the CD47-truncated monomer CAR on T cells could be an effective, dual CAR-T cell strategy for ovarian cancer, also applicable to other adenocarcinomas., Graphical Abstract, Tumors often escape immunotherapy by mutational downregulation of the nominal target antigen. Use of CAR-T cells with dual antigen specificity can mitigate this problem. Adenocarcinomas expressing low levels of TAG-72 are not killed by single specificity TAG-72 CAR-T cells, but they are killed by dual CAR-T cells targeting TAG-72 and CD47.

Hepatocarcinoma is one of the most prevalent gastroenterological cancers in the world with less effective therapy. As an oncofetal antigen and diagnostic marker for liver cancer, alpha-fetoprotein (AFP) possesses a variety of biological functions. Except for its diagnosis in liver cancer, AFP has become a target for liver cancer immunotherapy. Although the immunogenicity of AFP is weak and it could induce the immune escapes through inhibiting the function of dendritic cells, natural killer cells, and T lymphocytes, AFP has attracted more attention in liver cancer immunotherapy. By in vitro modification, the immunogenicity and immune response of AFP could be enhanced. AFP-modified immune cell vaccine or peptide vaccine has displayed the specific antitumor immunity against AFP-positive tumor cells and laid a better foundation for the immunotherapy of liver cancer.

5T4 is an oncofetal antigen with low expression in healthy tissues which is frequently overexpressed in different tumor types. Despite its overexpression in various malignancies and its association with poor prognosis, there are currently no marketed drugs that target this tumor antigen. We developed a novel antibody-drug conjugate (ADC), named SYD1875, comprising a humanized, HC41-cysteine-engineered IgG1 monoclonal antibody directed against 5T4, site-specifically conjugated to a proprietary cleavable synthetic duocarmycin-based linker-drug (vc-seco-DUBA). SYD1875 showed sub-nanomolar binding affinity to human and cynomolgus 5T4, rapid internalization, and induction of both target- and bystander-mediated cell killing. SYD1875 showed superior in vitro cytotoxicity and in vivo activity compared to A1-mcMMAF -also known as PF-6263507-, a 5T4-targeting ADC that is no longer in clinical development. A single dose of SYD1875 induced strong anti-tumor activity in patient-derived xenograft models of multiple tumor types with low, moderate and high 5T4 expression. The GLP toxicity study in cynomolgus monkey showed an acceptable toxicity and PK profile. A first-in-human dose-finding trial was initiated to evaluate safety and explore efficacy (NCT04202705). Citation Format: Patrick Groothuis, Danielle Jacobs, Kim Berentsen, Monique van der Vleuten, Ruud Coumans, Ronald Elgersma, Marion Blomenrohr, Diels van den Dobbelsteen, Patrick Beusker, Ruud Ubink, Miranda van der Lee, Wim H.A. Dokter. Introduction to the preclinical profile of SYD1875, a novel site-specifically conjugated duocarmycin-based 5T4-targeting antibody-drug conjugate [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 925.

The description of “serum sickness” more than a century ago in humans transfused with animal sera eventually led to identification of a class of human antibodies directed against glycans terminating in the common mammalian sialic acid N-Glycolylneuraminic acid (Neu5Gc), hereafter called “Neu5Gc-glycans.” The detection of such glycans in malignant and fetal human tissues initially raised the possibility that it was an oncofetal antigen. However, “serum sickness” antibodies were also noted in various human disease states. These findings spurred further research on Neu5Gc, and the discovery that it is not synthesized in the human body due to a human-lineage specific genetic mutation in the enzyme CMAH. However, with more sensitive techniques Neu5Gc-glycans were detected in smaller quantities on certain human cell types, particularly epithelia and endothelia. The likely explanation is metabolic incorporation of Neu5Gc from dietary sources, especially red meat of mammalian origin. This incorporated Neu5Gc on glycans appears to be the first example of a “xeno-autoantigen,” against which varying levels of “xeno-autoantibodies” are present in all humans. The resulting chronic inflammation or “xenosialitis” may have important implications in human health and disease, especially in conditions known to be aggravated by consumption of red meat. In this review, we will cover the early history of the discovery of “serum sickness” antibodies, the subsequent recognition that they were partly directed against Neu5Gc-glycans, the discovery of the genetic defect eliminating Neu5Gc production in humans, and the later recognition that this was not an oncofetal antigen but the first example of a “xeno-autoantigen.” Further, we will present comments about implications for disease risks associated with red meat consumption such as cancer and atherosclerosis. We will also mention the potential utility of these anti-Neu5Gc-glycan antibodies in cancer immunotherapy and provide some suggestions and perspectives for the future. Other reviews in this special issue cover many other aspects of this unusual pathological process, for which there appears to be no other described precedent.

// Li Wang 1, 2, * , Liuhong Pan 1, * , Min Yao 3, * , Yin Cai 1 , Zhizhen Dong 4 , Dengfu Yao 1 1 Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong 226001, China 2 Department of Medical Informatics, Medical School of Nantong University, Nantong 226001, China 3 Department of Immunology, Medical School of Nantong University, Nantong 226001, China 4 Department of Diagnostics, Affiliated Hospital of Nantong University, Nantong 226001, China * These authors contributed equally to this work Correspondence to: Dengfu Yao, email: yaodf@ahnmc.com Keywords: hepatocellular carcinoma, glypican-3, prognosis, tissue microarrays, immunohistochemistry Received: April 18, 2016 Accepted: May 23, 2016 Published: June 07, 2016 ABSTRACT Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide with poor prognosis. However, its prognostic evaluation is still an urgent problem. The objectives of this present study were to investigate oncofetal antigen glypican-3 (GPC-3) expression in HCC and their match para-cancerous tissues by the array technology with immunohistochemistry and estimate its value as a novel prognostic marker for HCC. The incidence of GPC-3 expression was 95.7 % in the cancerous tissues with significantly higher ( χ 2 = 33.824, P < 0.001) than that in the para-cancerous tissues (52.2 %). Abnormal expression of GPC-3 in HCC tissues was markedly related to poor or moderate differentiation ( P < 0.001), hepatitis B virus (HBV) infection ( P = 0.004), periportal cancer embolus ( P = 0.043), and tumor-node- metastasis staging ( P = 0.038 ). According to the univariate and multivariate analysis, the overall survival of HCC patients with high GPC-3 level was significantly worse than those with low or without GPC-3 expression ( P < 0.001), suggesting that abnormal GPC-3 expression should be an independent prognostic factor for HBV-related HCC patient’s survival.

Early specific diagnosis and effective treatment of hepatocellular carcinoma (HCC) are crucial. Expression of membrane-associated heparan sulfate proteoglycan glypican-3 (GPC-3) was recently found to increase as part of the malignant transformation of hepatocytes, and this increase is especially marked in patients with hepatitis B virus (HBV) infection, periportal cancerous embolus, or extra-hepatic metastasis. According to data from basic and clinical studies, the oncofetal antigen GPC-3 is a highly specific diagnostic biomarker of HCC and an indicator of its prognosis, and GPC-3 is also a promising target molecule for HCC gene therapy since it may play a crucial role in cell proliferation, metastasis, and invasion and it may mediate oncogenesis and oncogenic signaling pathways. This review summarizes recent advances in the use of oncofetal antigen GPC-3 to diagnose HBV-related HCC, estimate its prognosis, and its targeted therapy.

Peptide subunit vaccines are desirable because they increase control over the immune response and safety of the vaccine by reducing the risk of off-target responses to molecules other than the target antigen. The immunogenicity of most peptides, however, is low. Peptide nanoclusters (PNC) are proposed as a subunit peptide vaccine delivery system made completely of cross-linked peptide antigen that could improve the immunogenicity of a peptide vaccine. Proof of concept is demonstrated with oncofetal antigen (OFA), an immature laminin receptor protein expressed by many hematologic cancer cells but not by healthy cells. Peptide epitopes from this protein, called OFA 1, 2, and 3, were synthesized into PNC as a potential cancer peptide vaccine delivery system. PNC were formed by desolvation and stabilized with disulfide bonds using a trithiol cross-linker. Cysteines were added to the C-terminus of each peptide to assist in this cross-linking step, denoted OFA 1C, 2C, and 3C PNC. OFA 2C was found to form the smallest PNC, 148 ± 15 nm in diameter and stable in solution. This size is in the range where particles are readily internalized by dendritic cells (DCs) and may also passively diffuse to regional lymph nodes. OFA 2C PNC and soluble OFA 2C were internalized similarly by DCs in vitro, but only PNC resulted in significant peptide presentation by DCs. This indicates the potential for PNC to improve immune activation against this antigen. Additionally, PNC displayed higher retention at the intradermal injection site in vivo than soluble peptide, allowing more time to interact with DCs in an area of increased DC activity. While offering traditional nanoparticle benefits such as increased DC recognition, slower diffusion, and potential for multivalent cellular interactions, PNC also maximize antigen delivered per particle while minimizing off-target material delivery because the antigens are the main building blocks of the particle. With these properties, PNC are a delivery system with potential to increase peptide subunit vaccine immunogenicity for OFA and other peptide antigens.

Brain metastases from NSCLC are associated with a poor prognosis, and local radiotherapy is the most effective therapeutic strategy. The oncofetal protein IMP3 has been studied extensively, and evidence suggests that its expression is related to shorter overall survival and a more aggressive phenotype in solid malignancies. Here, the prognostic role of IMP3 was investigated in a cohort of patients with NSCLC brain metastases in correlation with survival and tumor histotype. A series of 42 NSCLC brain metastases samples was analyzed by tissue microarray and immunohistochemical staining for IMP3. IMP3 expression was associated with shorter overall survival in the whole series and in subgroups of metastases from non-neuroendocrine pulmonary malignancies and adenocarcinoma metastases. These results indicated that IMP3 is a strong prognostic factor in non-neuroendocrine brain metastases and in particular in patients with adenocarcinoma metastases.

Genetic replacement of adenoviral fiber knobs by ligands that enable tumor specific targeting of oncolytic adenoviruses is challenging because the fiber knob contributes to virus assembly. Here, we present a novel concept by describing stable recombinant adenoviruses with tumor specific infection mode. The fiber knob was replaced by endosialidaseNF (endoNF), the tailspike protein of bacteriophage K1F. EndoNF recognizes polysialic acid, an oncofetal antigen characteristic for high malignant tumors of neuroendocrine origin. An intramolecular chaperone contained in endoNF warrants folding and compensates for the knob function in virus assembly. Obtained recombinant viruses demonstrated polysialic acid dependent infection modes, strong oncolytic capacity with polysialic acid positive cells in culture and a high potential to inhibit tumor growth in a therapeutic mouse model of subcutaneous neuroblastoma. With a single genetic manipulation we achieved ablation of the fiber knob, introduction of a tumor specific ligand, and folding control over the chimeric fiber construct.

The 67 kDa high affinity laminin receptor (67LR) is a non-integrin cell surface receptor for laminin, the major component of basement membranes. Interactions between 67LR and laminin play a major role in mediating cell adhesion, migration, proliferation and survival. 67LR derives from homo- or hetero-dimerization of a 37 kDa cytosolic precursor (37LRP), most probably by fatty acid acylation. Interestingly, 37LRP, also called p40 or OFA/iLR (oncofetal antigen/immature laminin receptor), is a multifunctional protein with a dual activity in the cytoplasm and in the nucleus. In the cytoplasm, 37LRP it is associated with the 40S subunit of ribosome, playing a critical role in protein translation and ribosome biogenesis while in the nucleus it is tightly associated with nuclear structures, and bound to components of the cytoskeleton, such as tubulin and actin. 67LR is mainly localized in the cell membrane, concentrated in lipid rafts. Acting as a receptor for laminin is not the only function of 67LR; indeed, it also acts as a receptor for viruses, bacteria and prions. 67LR expression is increased in neoplastic cells and correlates with an enhanced invasive and metastatic potential. The primary function of 67LR in cancer is to promote tumor cell adhesion to basement membranes, the first step in the invasion-metastasis cascade. Thus, 67LR is overexpressed in neoplastic cells as compared to their normal counterparts and its overexpression is considered a molecular marker of metastatic aggressiveness in cancer of many tissues, including breast, lung, ovary, prostate, stomach, thyroid and also in leukemia and lymphoma. Thus, inhibiting 67LR binding to laminin could be a feasible approach to block cancer progression. Here, we review the current understanding of the structure and function of this molecule, highlighting its role in cancer invasion and metastasis and reviewing the various therapeutic options targeting this receptor that could have a promising future application.

Targeted cancer therapies have emerged as new treatment options for various cancer types. Among targets, receptor tyrosine kinases (RTKs) are among the most promising. ROR1 is a transmembrane RTK of importance during the normal embryogenesis for the central nervous system, heart, lung and skeletal systems, but is not expressed in normal adult tissues. However, ROR1 is overexpressed in several human malignancies and may act as a survival factor for tumor cells. Its unique expression by malignant cells may provide a target for novel therapeutics including monoclonal antibodies (mAbs) and small molecule inhibitors of tyrosine kinases (TKI) for the treatment of cancer. Promising preclinical results have been reported in e.g. chronic lymphocytic leukemia, pancreatic carcinoma, lung and breast cancer. ROR1 might also be an interesting oncofetal antigen for active immunotherapy. In this review, we provide an overview of the ROR1 structure and functions in cancer and highlight emerging therapeutic options of interest for targeting ROR1 in tumor therapy.

Background Glypican-3 (GPC3) is an oncofetal antigen that shows great promise as a biomarker for diagnosis of hepatocellular carcinoma (HCC), but there is no reliable kit that can be used to detect it in clinics. The aim of this study is to develop a stable performance kit for GPC3 detection in clinics. Design and methods The paired antibodies were identified through cycle-screening methods based on our previous research. Then, a double antibodies sandwich chemiluminescent immunoassay for detecting serum GPC3 was developed. The performance of the developed GPC3 diagnostic kit was evaluated by detecting the concentration of serum GPC3 and assessing its single or combined use with alpha fetoprotein (AFP) and cytokeratin 19 fragment (CK19) for HCC diagnosis. Results The assay demonstrated a linear range of 10–800 ng/ml, the cross-reactivity rate at 0.018% (AFP), 0.020% (carcino-embryonic antigen), and 0.021% (CK19), respectively. The minimum detectable concentration was 0.05 ng/ml; the intraassay coefficient of variation (CV) and interassay CV were both less than 10%, with good stability and reproducibility. GPC3 has a high sensitivity (54.2%) and specificity (99.4%) in diagnosing HCC. The level of GPC3 in HCC was robust higher than that in healthy or other liver diseases' sera (108.67 ± 230.04 ng/ml vs. 3.99 ± 7.68 ng/ml). The diagnostic sensitivity of GPC3 single or combined with CK19 and AFP for HCC was evaluated, and the rates were 54.2 and 90.6%, respectively. Conclusions An applicable chemiluminescent immunoassay with stable performance against GPC3 in diagnosing HCC has been established and the combination of GPC3 with CK19 and AFP could improve the diagnostic sensitivity for HCC.

T-antigen (Galβ1-3GalNAcα-1-Ser/Thr) is an oncofetal antigen that is commonly expressed as a carbohydrate determinant in many adenocarcinomas. Since it is associated with tumor progression and metastasis, production of recombinant antibodies specific for T-antigen could lead to the development of cancer diagnostics and therapeutics. Previously, we isolated and characterized 11 anti-T-antigen phage clones from a phage library displaying human single-chain antibodies (scFvs) and purified one scFv protein, 1G11. More recently, we purified and characterized 1E8 scFv protein using a Drosophila S2 expression system. In the current study, four anti-T-antigen scFv genes belonging to Groups 1-4 were purified from inclusion bodies expressed in Escherichia coli cells. Inclusion bodies isolated from E. coli cells were denatured in 3.5 M Gdn-HCl. Solubilized His-tagged scFv proteins were purified using Ni(2+)-Sepharose column chromatography in the presence of 3.5 M Gdn-HCl. Purified scFv proteins were refolded according to a previously published method of step-wise dialysis. Two anti-T-antigen scFv proteins, 1E6 and 1E8 that belong to Groups 1 and 2, respectively, were produced in sufficient amounts, thus allowing further characterization of their binding activity with T-antigen. Specificity and affinity constants determined using enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR), respectively, provided evidence that both 1E8 and 1E6 scFv proteins are T-antigen specific and suggested that 1E8 scFv protein has a higher affinity for T-antigen than 1E6 scFv protein.

Cancer stem cells (CSCs) can act as the cellular drivers of tumors harnessing stem cell properties that contribute to tumorigenesis either as founder elements or by the gain of stem cell traits by the malignant cells. Thus, CSCs can self-renew and generate the cellular heterogeneity of tumors including a hierarchical organization similar to the normal tissue. While the principle tumor growth contribution is often from the non-CSC components, it is the ability of small numbers of CSCs to avoid the effects of therapeutic strategies that can contribute to recurrence after treatment. However, identifying and characterizing CSCs for therapeutic targeting is made more challenging by their cellular potency being influenced by a particular tissue niche or by the capacity of more committed cells to regain stem cell functions. This review discusses the properties of CSCs including the limitations of the available cell surface markers, the assays that document tumor initiation and clonogenicity, the roles of epithelial mesenchymal transition and molecular pathways such as Notch, Wnt, Hippo and Hedgehog. The ability to target and eliminate CSCs is thought to be critical in the search for curative cancer treatments. The oncofetal tumor-associated antigen 5T4 (TBGP) has been linked with CSC properties in several different malignancies. 5T4 has functional attributes that are relevant to the spread of tumors including through EMT, CXCR4/CXCL12, Wnt, and Hippo pathways which may all contribute through the mobilization of CSCs. There are several different immunotherapies targeting 5T4 in development including antibody–drug conjugates, antibody-targeted bacterial super-antigens, a Modified Vaccinia Ankara-basedvaccine and 5T4-directed chimeric antigen receptor T-cells. These immune therapies would have the advantage of targeting both the bulk tumor as well as mobilized CSC populations.

The relationship between the adaptive CD4+ T-cell response and human cancer is unclear. The oncofetal antigen 5T4 is expressed in many human carcinomas, including colorectal cancer cells, but has limited expression on normal tissues. We previously identified anti-5T4 CD4+ T cells in a proportion of patients with colorectal cancer, and we extended this study to examine whether the quality or quantity of the T-cell response reflects tumor stage. An overlapping peptide library spanning 5T4 was used as a target to enumerate cognate IFN-γ+ CD4+ T cells [measured as spot-forming cells (SFC)/105 cultured T cells] in peripheral blood–derived lymphocytes following a 14-day in vitro culture period comparing patients preoperatively (n = 27) to healthy controls (n = 17). Robust 5T4-specific T-cell responses were present in 100% of healthy donors. There was a steady loss of T-cell responses with advancing tumors with a significant negative correlation from stage I to III (P = 0.008). The predictability of the decline meant