Tissue micro array analysis of ganglioside N-glycolyl GM3 expression and signal transducer and activator of transcription (STAT)-3 activation in relation to dendritic cell infiltration and microvessel density in non-small cell lung cancer

Current state-of-the-art on ganglioside-mediated immune modulation in the tumor microenvironment

Gangliosides are sialylated glycolipids, mainly present at the cell surface membrane, involved in a variety of cellular signaling events. During malignant transformation, the composition of these glycosphingolipids is altered, leading to structural and functional changes, which are often negatively correlated to patient survival. Cancer cells have the ability to shed gangliosides into the tumor microenvironment, where they have a strong impact on anti-tumor immunity and promote tumor progression. Since most ganglioside species show prominent immunosuppressive activities, they might be considered checkpoint molecules released to counteract ongoing immunosurveillance. In this review, we highlight the current state-of-the-art on the ganglioside-mediated immunomodulation, specified for the different immune cells and individual gangliosides. In addition, we address the dual role that certain gangliosides play in the tumor microenvironment. Even though some ganglioside species have been more extensively studied than others, they are proven to contribute to the defense mechanisms of the tumor and should be regarded as promising therapeutic targets for inclusion in future immunotherapy regimens.

N-glycolylneuraminic acid as a carbohydrate cancer biomarker

One of the forms of aberrant glycosylation in human tumors is the expression of N-glycolylneuraminic acid (Neu5Gc). The only known enzyme to biosynthesize Neu5Gc in mammals, cytidine-5'-monophosphate-N-acetylneuraminic acid (CMAH), appears to be genetically inactivated in humans. Regardless, low levels of Neu5Gc have been detected in healthy humans. Therefore, it is proposed that the presence of Neu5Gc in humans is from dietary acquisition, such as red meat. Notably, detection of elevated Neu5Gc levels has been repeatedly found in cancer tissues, cells and serum samples, thereby Neu5Gc-containing antigens may be exploited as a class of cancer biomarkers. Here we review the findings to date on using Neu5Gc-containing tumor glycoconjugates as a class of cancer biomarkers for cancer detection, surveillance, prognosis and therapeutic targets. We review the evidence that supports an emerging hypothesis of de novo Neu5Gc biosynthesis in human cancer cells as a source of Neu5Gc in human tumors, generated under certain metabolic conditions.

Current progress in the development of prophylactic and therapeutic vaccines

Vaccines are essential public health tools and play an important role in reducing the burden of infectious diseases in the population. Emerging infectious diseases and outbreaks pose new challenges for vaccine development, requiring the rapid design and production of safe and effective vaccines against diseases with limited resources. Here, we focus on the development of vaccines in broad fields ranging from conventional prophylactic vaccines against infectious diseases to therapeutic vaccines against chronic diseases and cancer providing a comprehensive overview of recent advances in eight different vaccine forms (live attenuated vaccines, inactivated vaccines, polysaccharide and polysaccharide conjugate vaccines, recombinant subunit vaccines, virus-like particle and nanoparticle vaccines, polypeptide vaccines, DNA vaccines, and mRNA vaccines) and the therapeutic vaccines against five solid tumors (lung cancer breast cancer colorectal cancer liver cancer and gastric cancer), three infectious diseases (human immunodeficiency virus, hepatitis B virus and human papillomavirus-induced diseases) and three common chronic diseases (hypertension, diabetes mellitus and dyslipidemia). We aim to provide new insights into vaccine technologies, platforms, applications and understanding of potential next-generation preventive and therapeutic vaccine technologies paving the way for the vaccines design in the future.

Preliminary Analysis of the Glycolipid Profile in Secondary Brain Tumors

Glycosphingolipids (GSLs) play numerous roles in cellular processes, including cell proliferation, apoptosis, inflammation, and cell signaling. Alteration of the GSLs metabolism leads to the accumulation of particular species of GSLs, which can lead to various pathologies, including carcinogenesis and metastasis; in essence, all neoplasms are characterized by the synthesis and aberrant organization of GSLs expressed on the cell surface. Secondary brain tumors make up the majority of intracranial cancers and generally present an unfavorable prognosis. In the present work, a native GSL mixture extracted and purified from a secondary brain tumor with primary pulmonary origin was obtained through extraction and purification and analyzed by MALDI TOF mass spectrometry. Research in the field of lipidomics could offer new data for the understanding of brain tropism and metastatic pathways, by studying the glycolipid molecules involved in the process of metastasis in general and in the production of brain metastases in particular. This could shed new light on the pattern of lipid glycosylation in secondary brain tumors, with a great impact on the effectiveness of cancer therapies, which could be adapted to the specific molecular pattern of the tumor.

SILAC-based quantitative proteomics and microscopy analysis of cancer cells treated with the N-glycolyl GM3-specific anti-tumor antibody 14F7

Cancer immunotherapy represents a promising approach to specifically target and treat cancer. The most common mechanisms by which monoclonal antibodies kill cells include antibody-dependent cell-mediated cytotoxicity, complement-dependent cytotoxicity and apoptosis, but also other mechanisms have been described. 14F7 is an antibody raised against the tumor-associated antigen NeuGc GM3, which was previously reported to kill cancer cells without inducing apoptotic pathways. The antibody was reported to induce giant membrane lesions in tumor cells, with apparent changes in the cytoskeleton. Here, we investigated the effect of humanized 14F7 on HeLa cells using stable isotope labeling with amino acids in cell culture (SILAC) in combination with LC-MS and live cell imaging. 14F7 did not kill the HeLa cells, however, it caused altered protein expression (MS data are available via ProteomeXchange with identifier PXD024320). Several cytoskeletal and nucleic-acid binding proteins were found to be strongly down-regulated in response to antibody treatment, suggesting how 14F7 may induce membrane lesions in cells that contain higher amounts of NeuGc GM3. The altered expression profile identified in this study thus contributes to an improved understanding of the unusual killing mechanism of 14F7.

Vaccine Therapy in Non-Small Cell Lung Cancer

Immunotherapy using immune checkpoint modulators has revolutionized the oncology field, emerging as a new standard of care for multiple indications, including non-small cell lung cancer (NSCLC). However, prognosis for patients with lung cancer is still poor. Although immunotherapy is highly effective in some cases, not all patients experience significant or durable responses, and further strategies are needed to improve outcomes. Therapeutic cancer vaccines are designed to exploit the body’s immune system to activate long-lasting memory against tumor cells that ensure tumor regression, with minimal toxicity. A unique feature of cancer vaccines lies in their complementary approach to boost antitumor immunity that could potentially act synergistically with immune checkpoint inhibitors (ICIs). However, single-line immunization against tumor epitopes with vaccine-based therapeutics has been disappointingly unsuccessful, to date, in lung cancer. The high level of success of several recent vaccines against SARS-CoV-2 has highlighted the evolving advances in science and technology in the vaccines field, raising hope that this strategy can be successfully applied to cancer treatments. In this review, we describe the biology behind the cancer vaccines, and discuss current evidence for the different types of therapeutic cancer vaccines in NSCLC, including their mechanisms of action, current clinical development, and future strategies.

Endothelial ganglioside GM3 regulates angiogenesis in solid tumors

Cancer cells require oxygen and nutrients for growth, making angiogenesis one of the essential components of tumor growth. Gangliosides, constituting membrane lipid rafts, regulate intracellular signal transduction and are involved in the malignancy of cancer cells. While endothelial cells, as well as cancer cells, express vast amounts of gangliosides, the precise function of endothelial gangliosides in angiogenesis remains unclear. In this study, we focused on gangliosides of vascular endothelial cells and analyzed their functions on tumor angiogenesis. In human breast cancer, GM3 synthase was highly expressed in vascular endothelial cells as well as immune cells. Angiogenesis increased in GM3S-KO mice. In BAEC, RNA interference of GM3S showed increased cellular invasion and oxidative stress tolerance through activation of ERK. In the breast cancer model, GM3-KO mice showed an increase in tumor growth and angiogenesis. These results suggest that the endothelial ganglioside GM3 regulates tumor angiogenesis by suppressing cellular invasion and oxidative stress tolerance in endothelial cells.

Regulation of EGFR activation and signaling by lipids on the plasma membrane

Lipids on the plasma membrane are not only components of the membrane biophysical structures but also regulators of receptor functions. Recently, the critical roles of lipid-protein interactions have been intensively highlighted. Epidermal growth factor receptor (EGFR) is one of the most extensively studied receptors exhibiting various lipid interactions, including interactions with phosphatidylcholine, phosphatidylserine, phosphatidylinositol phosphate, cholesterol, gangliosides, and palmitate. Here, we review recent findings on how direct interaction with these lipids regulates EGFR activation and signaling, providing unprecedented insight into the comprehensive roles of various lipids in the control of EGFR functions. Finally, the current limitations in investigating lipid-protein interactions and novel technologies to potentially overcome these limitations are discussed.

Ganglioside GM3 and Its Role in Cancer

Ganglioside GM3 is strongly related with human tumors, such as lung, brain cancers and melanomas, and more and more evidences have revealed that GM3 possesses powerful effects on cancer development and progression. GM3 is over expressed on several types of cancers, and can be as a tumor-associated carbohydrate antigen, used for immunotherapy of cancers. GM3 can also inhibit tumor cells growth by anti-angiogenesis or motility and so on. Especially, GM3 has effects on the EGFR tyrosine kinase signaling, uPAR-related signaling and glycolipid-enriched microdomains, which are essential for cancer signaling conduction. It is obvious that GM3 will be a promising target for cancer treatment.

Expression of bladder cancer-associated glycans in murine tumor cell lines

The characterization of murine cell lines is of great importance in order to identify preclinical models that could resemble human diseases. Aberrant glycosylation includes the loss, excessive or novel expression of glycans and the appearance of truncated structures. MB49 and MB49-I are currently the only two murine cell lines available for the development of preclinical bladder cancer models. The glycans Lewis X (LeX), Sialyl lewis X (SLeX) and Sialyl Tn (STn) have previously been associated with aggressiveness, dissemination and poor prognosis in human bladder cancer, additionally N-glycolyl GM3 (NGcGM3) is a neo-antigen expressed in many types of tumors; however, to the best of our knowledge, its expression has not previously been assessed in this type of cancer. Taking into account the relevance of glycans in tumor biology and considering that they can act as targets of therapies and biomarkers, the present study evaluated the expression of LeX, SLeX, STn and NGcGM3 in MB49 and MB49-I cells, in different growth conditions such as monolayer cultures, three-dimensional multicellular spheroids and mouse heterotopic and orthotopic tumors. The expression of LeX was not detected in either cell line, whereas SLeX was expressed in monolayers, spheroids and orthotopic tumors of both cell lines. STn was only identified in MB49 monolayers and spheroids. There are no reports concerning the expression of NGcGM3 in human or murine bladder cancer. In our hands, MB49 and MB49-I expressed this ganglioside in all the growth conditions evaluated. The assessment of its expression in cancer cell lines and patient tumors is of great importance, considering the relevance of this ganglioside in tumor biology. The data obtained by the present study demonstrates that glycan expression may be substantially altered depending on the growth conditions, highlighting the importance of the characterization of murine cancer models. To the best of our knowledge, the present study is the first to examine the expression of cancer-associated glycans, in the two murine cell lines available for the development of preclinical studies in bladder cancer.

Antibody-dependent cell-mediated cytotoxicity induced by active immunotherapy based on racotumomab in non-small cell lung cancer patients

Antitumor strategies based on positive modulation of the immune system currently represent therapeutic options with prominent acceptance for cancer patients' treatment due to its selectivity and higher tolerance compared to chemotherapy. Racotumomab is an anti-idiotype (anti-Id) monoclonal antibody (mAb) directed to NeuGc-containing gangliosides such as NeuGcGM3, a widely reported tumor-specific neoantigen in many human cancers. Racotumomab has been approved in Latin American countries as an active immunotherapy for advanced non-small cell lung cancer (NSCLC) treatment. In this work, we evaluated the induction of Ab-dependent cell-mediated cytotoxicity (ADCC) in NSCLC patients included in a phase III clinical trial, in response to vaccination with racotumomab. The development of anti-NeuGcGM3 antibodies (Abs) in serum samples of immunized patients was first evaluated using the NeuGcGM3-expressing X63 cells, showing that racotumomab vaccination developed antigen-specific Abs that are able to recognize NeuGcGM3 expressed in tumor cell membranes. ADCC response against NeuGcGM3-expressing X63 (target) was observed in racotumomab-treated- but not in control group patients. When target cells were depleted of gangliosides by treatment with a glucosylceramide synthase inhibitor, we observed a significant reduction of the ADCC activity developed by sera from racotumomab-vaccinated patients, suggesting a target-specific response. Our data demonstrate that anti-NeuGcGM3 Abs induced by racotumomab vaccination are able to mediate an antigen-specific ADCC response against tumor cells in NSCLC patients.

GM3(Neu5Gc) ganglioside: an evolution fixed neoantigen for cancer immunotherapy

Numerous molecules have been considered as targets for cancer immunotherapy because of their levels of expression on tumor cells, their putative importance for tumor biology, and relative immunogenicity. In this review we focus on the ganglioside GM3(Neu5Gc), a glycosphingolipid present on the outer side of the plasma membrane of vertebrate cells. The reasons for selecting GM3(Neu5Gc) as a tumor-specific antigen and its use as a target for cancer immunotherapy are discussed, together with the development of antitumor therapies focused on this target by the Center of Molecular Immunology (CIM, Cuba).

Prognostic role of STAT3 in solid tumors: a systematic review and meta-analysis

Accumulated studies have provided controversial evidences of the association between signal transducer and activator of transcription proteins 3 (STAT3) expression and survival of human solid tumors. To address this inconsistency, we performed a meta-analysis with 63 studies identified from PubMed, Medline and EBSCO. We found STAT3 overexpression was significantly associated with worse 3-year overall survival (OS) (OR = 2.06, 95% CI = 1.57 to 2.71, P < 0.00001) and 5-year OS (OR = 2.00, 95% CI = 1.53 to 2.63, P < 0.00001) of human solid tumors. Similar results were observed when disease free survival (DFS) were analyzed. Subgroup analysis showed that elevated STAT3 expression was associated with poor prognosis of gastric cancer, lung cancer, gliomas, hepatic cancer, osteosarcoma, prostate cancer, pancreatic cancer but better prognosis of breast cancer. The correlation between STAT3 and survival of solid tumors was related to its phosphorylated state. High expression level of STAT3 was also associated with advanced tumor stage. In conclusion, elevated STAT3 expression is associated with poor survival in most solid tumors. STAT3 is a valuable biomarker for prognosis prediction and a promising therapeutic target in human solid tumors.

EGFR and KRAS mutations do not enrich for the activation of IL-6, JAK1 or phosphorylated STAT3 in resected lung adenocarcinoma

Resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) against EGFR mutant lung adenocarcinoma develops after a median of nine to thirteen months. Upregulation of the interleukin-6 (IL-6)/Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway may be a potential source of resistance to EGFR TKIs. We undertook a detailed assessment of the IL-6/JAK1/phosphorylated STAT3 (pSTAT3) pathway in resected lung adenocarcinoma specimens, with special interest in whether the presence of an EGFR mutation enriched for pSTAT3 positivity. Tumours from 143 patients with resected lung adenocarcinoma were assessed. EGFR and KRAS mutation status were scanned for with high-resolution melting and confirmed by polymerase chain reaction. Immunohistochemisty (IHC) was performed for IL-6, gp130, JAK1 and pSTAT3. Two methods for assigning IHC positivity were assessed (the presence of any positivity, and the presence of positivity at an H score >40). We found statistically significant associations between IL-6, JAK1 and pSTAT3 measured by IHC, consistent with the activation of the pathway in clinical specimens. No relationship was demonstrated between members of this pathway and oncogenic mutations in EGFR or KRAS. However, a proportion of tumours with EGFR mutations showed staining for IL-6, JAK1 and pSTAT3. No correlations with clinicopathologic features or survival outcomes were found for IL-6, JAK1 or pSTAT3 staining. The presence of EGFR or KRAS mutations did not enrich for the activation of IL-6, JAK1 or pSTAT3. pSTAT3 may still play a role in resistance to EGFR TKIs in clinical practice.

Correlation between p-STAT3 overexpression and prognosis in lung cancer: A systematic review and meta-analysis

Objective

Previous studies have shown the correlation between p-STAT3 overexpression and prognosis in a variety of human tumors. However, their correlation in lung cancer remains controversial. We performed a systematic review and meta-analysis to explore the correlation between p-STAT3 overexpression and prognosis in lung cancer patients.

Methods

We searched PubMed, Embase, Web of Science, CNKI, VIP, and WanFang Data to identify relevant studies. Two reviewers independently screened the literature search results, extracted data, and assessed the methodological quality of the included studies. Then, meta-analysis was performed by using Review Manager 5.3 and STATA 14 software. A random-effect model was employed to evaluate all related pooled results. Statistical heterogeneity of each study was assessed by I². Publication bias was determined by funnel plot and the Begg’s or Egger’s tests.

Results

Eventually, 13 studies were included in present meta-analysis. Among these 13 studies, 8 studies were associated with the overall survival of lung cancer and 10 studies with other clinicopathological characteristics. The results of this meta-analysis suggested that p-STAT3 overexpression may be a poor prognosis biomarker in lung cancer (HR: 1.23; 95% CI: 1.04–1.46; P = 0.02). In terms of other clinicopathological characteristics, p-STAT3 overexpression was more frequent to advanced TNM stages ranging from III to IV (OR: 1.92; 95% CI: 1.13–3.27; P = 0.02) and lymphatic node metastasis (OR: 1.81; 95% CI: 1.20–2.72; P = 0.004). But, it was not associated with tumor differentiation (OR: 0.82; 95% CI: 0.44–1.53; P = 0.54).

Conclusion

p-STAT3 overexpression has significant correlation with poorer overall survival of lung cancer patients, as well as with more advanced TNM stages and lymph node metastasis. Thus, it may serve a biomarker for poor prognosis in lung cancer. Nevertheless, our findings should be confirmed by large prospective studies.

Extracellular Proton Concentrations Impacts LN229 Glioblastoma Tumor Cell Fate via Differential Modulation of Surface Lipids

Background

Glioblastoma multiforme (GBM) is a highly aggressive form of brain cancer with marginal survival rates. GBM extracellular acidosis can profoundly impact its cell fate heterogeneities and progression. However, the molecules and mechanisms that enable GBM tumor cells acid adaptation and consequent cell fate competencies are weakly understood. Since extracellular proton concentrations (pHe) directly intercept the tumor cell plasma membrane, surface lipids must play a crucial role in pHe-dependent tumor cell fate dynamics. Hence, a more detailed insight into the finely tuned pH-dependent modulation of surface lipids is required to generate strategies that can inhibit or surpass tumor cell acid adaptation, thereby forcing the eradication of heterogeneous oncogenic niches, without affecting the normal cells.

Results

By using image-based single cell analysis and physicochemical techniques, we made a small-scale survey of the effects of pH ranges (physiological: pHe 7.4, low: 6.2, and very low: 3.4) on LN229 glioblastoma cell line surface remodeling and analyzed the consequent cell fate heterogeneities with relevant molecular targets and behavioral assays. Through this basic study, we uncovered that the extracellular proton concentration (1) modulates surface cholesterol-driven cell fate dynamics and (2) induces ‘differential clustering’ of surface resident GM3 glycosphingolipid which together coordinates the proliferation, migration, survival, and death reprogramming via distinct effects on the tumor cell biomechanical homeostasis. A novel synergy of anti-GM3 antibody and cyclophilin A inhibitor was found to mimic the very low pHe-mediated GM3 supraclustered conformation that elevated the surface rigidity and mechano-remodeled the tumor cell into a differentiated phenotype which eventually succumbed to the anoikis type of cell death, thereby eradicating the tumorigenic niches.

Conclusion and significance

This work presents an initial insight into the physicochemical capacities of extracellular protons in the generation of glioblastoma tumor cell heterogeneities and cell death via the crucial interplay of surface lipids and their conformational changes. Hence, monitoring of proton–cholesterol–GM3 correlations in vivo through diagnostic imaging and in vitro in clinical samples may assist better tumor staging and prognosis. The emerged insights have further led to the translation of a ‘pH-dependent mechanisms of oncogenesis control’ into the surface targeted anti-GBM therapeutics.

Dysregulation of CUL4A and CUL4B Ubiquitin Ligases in Lung Cancer

The Cullin-RING ubiquitin ligase 4 (CRL4) is implicated in controlling cell cycle, DNA damage repair, and checkpoint response based on studies employing cell lines and mouse models. CRL4 proteins, including CUL4A and CUL4B, are often highly accumulated in human malignancies. Elevated CRL4 attenuates DNA damage repair and increases genome instability that is believed to facilitate tumorigenesis. However, this has yet to be evaluated in human patients with cancer. In our study, 352 lung cancer and 62 normal lung specimens of Asian origin were constructed into tissue microarrays of four distinct lung cancer subtypes. Expression of CUL4A, CUL4B, and their substrates was detected by immunohistochemistry and analyzed statistically for their prognostic value and association with DNA damage response and genomic instability. Our results show that both CUL4A and CUL4B are overexpressed in the majority of lung carcinomas (P_CUL4A <0.001 and P_CUL4B <0.001) and significantly associated with tumor size (P_CUL4A <0.001 and P_CUL4B = 0.002), lymphatic invasion (P_CUL4A = 0.004 and P_CUL4B <0.001), metastasis (P_CUL4A = 0.019 and P_CUL4B = 0.006), and advanced TNM stage (P_CUL4A <0.001 and P_CUL4B <0.001), which parallels gene amplification and abnormal activation of the canonical WNT signaling. Moreover, overexpression of CUL4A, but not CUL4B, is significantly associated with tobacco smoking (p = 0.01) and is inversely correlated with XPC and P21, both of which are substrates of CUL4A (P_CUL4A = 0.019 and P_CUL4B = 0.006). Higher levels of CUL4A or CUL4B are significantly associated with the overall survival of patients (P_CUL4A <0.001 and P_CUL4B <0.001) and progression-free survival (P_CUL4A <0.001 and P_CUL4B = 0.001). Our findings revealed that CUL4A and CUL4B are differentially associated with etiologic factors for pulmonary malignancies and are independent prognostic markers for the survival of distinct lung cancer subtypes.

Glycolipids and Lectins in Endocytic Uptake Processes

A host of endocytic processes has been described at the plasma membrane of eukaryotic cells. Their categorization has most commonly referenced cytosolic machinery, of which the clathrin coat has occupied a preponderant position. In what concerns intra-membrane constituents, the focus of interest has been on phosphatidylinositol lipids and their capacity to orchestrate endocytic events on the cytosolic leaflet of the membrane. The contribution of extracellular determinants to the construction of endocytic pits has received much less attention, depite the fact that (glyco)sphingolipids are exoplasmic leaflet fabric of membrane domains, termed rafts, whose contributions to predominantly clathrin-independent internalization processes is well recognized. Furthermore, sugar modifications on extracellular domains of proteins, and sugar-binding proteins, termed lectins, have also been linked to the uptake of endocytic cargoes at the plasma membrane. In this review, we first summarize these contributions by extracellular determinants to the endocytic process. We thus propose a molecular hypothesis - termed the GL-Lect hypothesis - on how GlycoLipids and Lectins drive the formation of compositional nanoenvrionments from which the endocytic uptake of glycosylated cargo proteins is operated via clathrin-independent carriers. Finally, we position this hypothesis within the global context of endocytic pathway proposals that have emerged in recent years.

Frequent co-expression of EGFR and NeuGcGM3 ganglioside in cancer: it's potential therapeutic implications

Interaction between epidermal growth factor receptor (EGFR) signaling with GM3 ganglioside expression has been previously described. However, little is known about EGFR and NeuGcGM3 co-expression in cancer patients and their therapeutic implications. In this paper, we evaluate the co-expression of EGFR and NeuGcGM3 ganglioside in tumors from 92 patients and in two spontaneous lung metastasis models of mice (Lewis lung carcinoma (3LL-D122) in C57BL/6 and mammary carcinoma (4T1) in BALB/c). As results, co-expression of EGFR and NeuGcGM3 ganglioside was frequently observed in 63 of 92 patients (68 %), independently of histological subtype. Moreover, EGFR is co-expressed with NeuGcGM3 ganglioside in the metastasis of 3LL-D122 and 4T1 murine models. Such dual expression appears to be therapeutically relevant, since combined therapy with mAbs against these two molecules synergistically increase the survival of mice treated. Overall, our results suggest that NeuGcGM3 and EGFR may coordinately contribute to the tumor cell biology and that therapeutic combinations against these two targets might be a valid strategy to explore.

Association of Nuclear PIM1 Expression with Lymph Node Metastasis and Poor Prognosis in Patients with Lung Adenocarcinoma and Squamous Cell Carcinoma

Increasing evidence indicates that aberrant expression of PIM1, p-STAT3 and c-MYC is involved in the pathogenesis of various solid tumors, but its prognostic value is still unclear in non-small cell lung cancer (NSCLC). Here, we sought to evaluate the expression and prognostic role of these markers in patients with lung adenocarcinoma (AD) and squamous cell carcinoma (SCC). Real time RT-PCR and Western blotting was used to analyze the mRNA and protein expression of PIM1 in NSCLC cell lines, respectively. The expression of PIM1, p-STAT3, and c-MYC was immunohistochemically tested in archival tumor samples from 194 lung AD and SCC patients. High nuclear PIM1 expression was detected in 43.3% of ADs and SCCs, and was significantly correlated with lymph node (LN) metastasis (P = 0.028) and histology (P = 0.003). High nuclear PIM1 expression (P = 0.034), locally advanced stage (P < 0.001), AD (P = 0.007) and poor pathologic differentiation (P = 0.002) were correlated with worse disease-free survival (DFS). High nuclear PIM1 expression (P = 0.009), advanced clinical stage (P < 0.001) and poor pathologic differentiation (P = 0.004) were independent unfavorable prognostic factors for overall survival (OS). High p-STAT3 expression was not associated with OS but significantly correlated with LN metastasis, while c-MYC was not significantly correlated with any clinicopathological parameter or survival. Therefore, in AD and SCC patients, nuclear PIM1 expression level is an independent factor for DFS and OS and it might serve as a predictive biomarker for outcome.

Dysregulated Expression of Glycolipids in Tumor Cells: From Negative Modulator of Anti-tumor Immunity to Promising Targets for Developing Therapeutic Agents

Glycolipids are complex molecules consisting of a ceramide lipid moiety linked to a glycan chain of variable length and structure. Among these are found the gangliosides, which are sialylated glycolipids ubiquitously distributed on the outer layer of vertebrate plasma membranes. Changes in the expression of certain species of gangliosides have been described to occur during cell proliferation, differentiation, and ontogenesis. However, the aberrant and elevated expression of gangliosides has been also observed in different types of cancer cells, thereby promoting tumor survival. Moreover, gangliosides are actively released from the membrane of tumor cells, having a strong impact on impairing anti-tumor immunity. Beyond the undesirable effects of gangliosides in cancer cells, a substantial number of cancer immunotherapies have been developed in recent years that have used gangliosides as the main target. This has resulted in successful immune cell- or antibody-responses against glycolipids, with promising results having been obtained in clinical trials. In this review, we provide a general overview on the metabolism of glycolipids, both in normal and tumor cells, as well as examining glycolipid-mediated immune modulation and the main successes achieved in immunotherapies using gangliosides as molecular targets.

Prognostic Significance of N-Glycolyl GM3 Ganglioside Expression in Non-Small Cell Lung Carcinoma Patients: New Evidences

The prognostic role of N-glycolyl GM3 ganglioside (NeuGcGM3) expression in non-small cell lung carcinoma (NSCLC) still remains controversial. In this study, the NeuGcGM3 expression was reevaluated using an increased number of NSCLC cases and the 14F7 Mab (a highly specific IgG1 raised against NeuGcGM3). An immunohistochemical score integrating the percentage of 14F7-positive cells and the intensity of reaction was applied to reassess the relationship between NeuGcGM3 expression, some clinicopathological features, and the overall survival (OS) of NSCLC patients. The double and the triple expression of NeuGcGM3 with the epidermal growth factor receptor (EGFR) and/or its ligand, the epidermal growth factor (EGF), were also evaluated. NeuGcGM3 expression correlates with both S-Phase fraction (p = 0.006) and proliferation index (p = 0.000). Additionally, NeuGcGM3 expression was associated with a poor OS of patients in both univariate (p = 0.020) and multivariate (p = 0.010) analysis. Moreover, the double and/or the triple positivity of tumors to NeuGcGM3, EGFR, and/or EGF permitted us to identify phenotypes of NSCLC with a more aggressive biological behavior. Our results are in agreement with the negative prognostic significance of NeuGcGM3 expression in NSCLC patients. However, standardization of techniques to determine the expression of NeuGcGM3 in NSCLC as well as the implementation of a universal scoring system is recommended.

Activated STAT3 correlates with prognosis of non-small cell lung cancer and indicates new anticancer strategies

PURPOSE

Aberrant activation of the signal transducer and activator of transcription 3 (STAT3) occurs in many human tumors. Many studies have provided compelling evidence for the critical role of aberrant STAT3 activity in malignant transformation and tumor progression. But few of them provided data on whether activated STAT3 overexpression correlated with patients' prognosis. Here, we define the relationship between phosphorylated STAT3 (pSTAT3) function and prognosis of non-small cell lung cancer (NSCLC).

METHODS

Immunohistochemical analyses were carried out on 82 surgically resected NSCLC tissues to evaluate the expression level of pSTAT3. The Kaplan-Meier method was used to calculate the survival rate, and the log-rank test was performed to compare the survival difference. Cox regression analysis was performed to identify prognostic risk factors. All statistic analyses were performed with SPSS11.5 statistical software. Differences were considered significant when the P value was <0.05.

RESULTS

In this study, we identified nuclear pSTAT3 expression in 59.76 % of tumors. pSTAT3 expression was correlated with differentiation degree of tumors (P < 0.05), lymph node metastasis status (P < 0.01), clinical stage of tumors (P < 0.01) and the prognosis of NSCLC patients after surgical resection (P < 0.05).

CONCLUSIONS

pSTAT3 overexpression is an important factor related to prognosis of NSCLC patients and indicates new anticancer strategies.

Sclerotium rolfsii lectin induces stronger inhibition of proliferation in human breast cancer cells than normal human mammary epithelial cells by induction of cell apoptosis

Sclerotium rolfsii lectin (SRL) isolated from the phytopathogenic fungus Sclerotium rolfsii has exquisite binding specificity towards O-linked, Thomsen-Freidenreich (Galβ1-3GalNAcα1-Ser/Thr, TF) associated glycans. This study investigated the influence of SRL on proliferation of human breast cancer cells (MCF-7 and ZR-75), non-tumorigenic breast epithelial cells (MCF-10A) and normal mammary epithelial cells (HMECs). SRL caused marked, dose-dependent, inhibition of proliferation of MCF-7 and ZR-75 cells but only weak inhibition of proliferation of non-tumorigenic MCF-10A and HMEC cells. The inhibitory effect of SRL on cancer cell proliferation was shown to be a consequence of SRL cell surface binding and subsequent induction of cellular apoptosis, an effect that was largely prevented by the presence of inhibitors against caspases -3, -8, or -9. Lectin histochemistry using biotin-labelled SRL showed little binding of SRL to normal human breast tissue but intense binding to cancerous tissues. In conclusion, SRL inhibits the growth of human breast cancer cells via induction of cell apoptosis but has substantially less effect on normal epithelial cells. As a lectin that binds specifically to a cancer-associated glycan, has potential to be developed as an anti-cancer agent.

MALDI imaging mass spectrometry profiling of N-glycans in formalin-fixed paraffin embedded clinical tissue blocks and tissue microarrays

A recently developed matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) method to spatially profile the location and distribution of multiple N-linked glycan species in frozen tissues has been extended and improved for the direct analysis of glycans in clinically derived formalin-fixed paraffin-embedded (FFPE) tissues. Formalin-fixed tissues from normal mouse kidney, human pancreatic and prostate cancers, and a human hepatocellular carcinoma tissue microarray were processed by antigen retrieval followed by on-tissue digestion with peptide N-glycosidase F. The released N-glycans were detected by MALDI-IMS analysis, and the structural composition of a subset of glycans could be verified directly by on-tissue collision-induced fragmentation. Other structural assignments were confirmed by off-tissue permethylation analysis combined with multiple database comparisons. Imaging of mouse kidney tissue sections demonstrates specific tissue distributions of major cellular N-linked glycoforms in the cortex and medulla. Differential tissue distribution of N-linked glycoforms was also observed in the other tissue types. The efficacy of using MALDI-IMS glycan profiling to distinguish tumor from non-tumor tissues in a tumor microarray format is also demonstrated. This MALDI-IMS workflow has the potential to be applied to any FFPE tissue block or tissue microarray to enable higher throughput analysis of the global changes in N-glycosylation associated with cancers.

Immunotherapy: is a minor god yet in the pantheon of treatments for lung cancer?

Immunotherapy has been studied for many years in lung cancer without significant results, making the majority of oncologists quite skeptical about its possible application for non-small cell lung cancer treatment. However, the recent knowledge about immune escape and subsequent 'cancer immunoediting' has yielded the development of new strategies of cancer immunotherapy, heralding a new era of lung cancer treatment. Cancer vaccines, including both whole-cell and peptide vaccines have been tested both in early and advanced stages of non-small cell lung cancer. New immunomodulatory agents, including anti-CTLA4, anti-PD1/PDL1 monoclonal antibodies, have been investigated as monotherapy in metastatic lung cancer. To date, these treatments have shown impressive results of efficacy and tolerability in early clinical trials, leading to testing in several large, randomized Phase III trials. As these results will be confirmed, these drugs will be available in the near future, offering new exciting therapeutic options for lung cancer treatment.

Molecular recognition of gangliosides and their potential for cancer immunotherapies

Gangliosides are sialic-acid-containing glycosphingolipids expressed on all vertebrate cells. They are primarily positioned in the plasma membrane with the ceramide part anchored in the membrane and the glycan part exposed on the surface of the cell. These lipids have highly diverse structures, not the least with respect to their carbohydrate chains, with N-acetylneuraminic acid (NeuAc) and N-glycolylneuraminic acid (NeuGc) being the two most common sialic-acid residues in mammalian cells. Generally, human healthy tissue is deficient in NeuGc, but this molecule is expressed in tumors and in human fetal tissues, and was hence classified as an onco-fetal antigen. Gangliosides perform important functions through carbohydrate-specific interactions with proteins, for example, as receptors in cell–cell recognition, which can be exploited by viruses and other pathogens, and also by regulating signaling proteins, such as the epidermal growth factor receptor (EGFR) and the vascular endothelial growth factor receptor (VEGFR), through lateral interaction in the membrane. Through both mechanisms, tumor-associated gangliosides may affect malignant progression, which makes them attractive targets for cancer immunotherapies. In this review, we describe how proteins recognize gangliosides, focusing on the molecular recognition of gangliosides associated with cancer immunotherapy, and discuss the importance of these molecules in cancer research.

Pilot study of a novel combination of two therapeutic vaccines in advanced non-small-cell lung cancer patients

Cancer vaccines contain tumor antigens in a pro-inflammatory context with the purpose to generate potent antitumor immune responses. However, tumor cells develop different immunosuppressive mechanisms that limit the effectiveness of an anticancer immune response. Therefore, therapeutic vaccine treatment alone is usually not sufficient to generate tumor regression or survival improvement, especially in the advanced disease scenario in which most clinical studies have been conducted. Combining cancer vaccines with different anticancer therapies such as chemotherapy, radiotherapy and other immunotherapeutic agents has had different levels of success. However, the combination of cancer vaccines with different mechanisms of action has not been explored in clinical trials. To address this issue, the current review summarizes the main clinical and immunological results obtained with two different therapeutic vaccines used in advanced non-small-cell lung cancer patients, inducing an immune response against epidermal growth factor (CIMAvax-EGF) and NGcGM3 ganglioside (racotumomab). We also discuss preliminary findings obtained in a trial of combination of these two vaccines and future challenges with these therapies.

Actual status of therapeutic vaccination in non-small cell lung cancer

Lung cancer is the leading cause of cancer-related death worldwide. Although treatment methods such as surgery, radiotherapy and/or chemotherapy have improved, prognosis remains unsatisfactory, and developing new therapeutic strategies is still an urgent matter. Immunotherapy is a novel therapeutic approach wherein activated immune cells can specifically kill tumour cells. Several lung cancer vaccines have demonstrated prolonged survival time in phase II and III trials, and several clinical trials are under investigation. However, many clinical trials involving cancer vaccination with defined tumour antigens have shown this method to work only in a small number of patients. Cancer immunotherapy is not completely effective in eradicating tumour cells because they evade host immune control.

A randomized, multicenter, placebo-controlled clinical trial of racotumomab-alum vaccine as switch maintenance therapy in advanced non-small cell lung cancer patients

PURPOSE

Racotumomab-alum is an anti-idiotype vaccine targeting the NeuGcGM3 tumor-associated ganglioside. This clinical trial was conducted to provide a preliminary estimate of efficacy and safety of racotumomab as switch maintenance for patients with advanced non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

Patients with stage IIIb/IV NSCLC who have at least stable disease after first-line chemotherapy were randomized 1:1 to racotumomab-alum (5 immunizations every 2 weeks and re-immunizations every 4 weeks) or placebo. Treatment was administered beyond progressive disease, until severe performance status worsening or toxicity. At progression, only five patients per group received further anticancer therapy. The primary endpoint was overall survival (OS).

RESULTS

One-hundred and seventy-six patients were randomized to racotumomab-alum (n = 87) and placebo (n = 89). Median OS was 8.23 and 6.80 months, respectively [HR, 0.63; 95% confidence interval (CI), 0.46-0.87; P = 0.004]. Median progression-free survival (PFS) in vaccinated patients was 5.33 versus 3.90 months for placebo (HR, 0.73; 95% CI 0.53-0.99; P = 0.039). The most common adverse events in the racotumomab-alum arm were burning and pain at the injection site, bone pain, and asthenia. A high antibody response of IgM and IgG isotype against the NeuGcGM3 ganglioside was obtained. Hyperimmune sera were able to specifically recognize and kill the NeuGcGM3-expressing L1210 cell line. Patients who developed anti-NeuGcGM3 antibodies capable to bind and kill ≥30% L1210 cells showed longer median survival times.

CONCLUSIONS

Switch maintenance with racotumomab-alum is an effective and a well-tolerated treatment option for patients with advanced NSCLC.

Glycans in immune recognition and response

Glycans at the forefront of cells facilitate immune recognition processes. Cancer cells commonly present altered cell surface glycosylation, especially manifested in the expression of sialic acid at the termini of glycolipids and glycoproteins. Although tumor-associated carbohydrate antigens (TACAs) result in expression of altered-self, most such carbohydrates do not elicit strong humoral responses. Various strategies had been devised to elicit increased immunogenicity of such TACA aiming for potent immunotherapeutic antibodies or cancer vaccines. However some carbohydrates are immunogenic in humans and hold potential for novel glycotherapies. N-Glycolylneuraminic acid (Neu5Gc) is a foreign immunogenic sugar in humans originating from the diet (e.g., red meat) and subsequently expressed on the cell surface, especially accumulating on carcinoma. Consequently, the human immune system detects this non-self carbohydrate generating a broad anti-Neu5Gc antibody response. The co-existence of Neu5Gc/anti-Neu5Gc within humans spurs chronic inflammation mediated disease, including cancer. Concurrently, anti-Neu5Gc antibodies hold potential for novel targeted therapy. αGal is another foreign immunogenic carbohydrate antigen in humans and all humans have circulating anti-Gal antibodies. This review aims to describe the immunogenicity of Neu5Gc and its implications for human diseases, highlighting differences and similarities with αGal and its potential for novel targeted theranostics.

Prognostic Role of 14F7 Mab Immunoreactivity against N-Glycolyl GM3 Ganglioside in Colon Cancer

Purpose. To assess the prognostic role of 14F7 Mab immunoreactivity, against N-Glycolyl GM3 ganglioside, in patients with colon cancer (CC) and to evaluate the relationship between its expression and clinicopathological features. Methods. Paraffin-embedded specimens were retrospectively collected from 50 patients with CC operated between 2004 and 2008. 14F7 Mab staining was determined by immunohistochemistry technique and its relation with survival and clinicopathologic features was evaluated. Results. The reactivity of 14F7 Mab was detected in all cases. Most cases had high level of immunostaining (70%) that showed statistical correlation with TNM stage (P = 0.025). In univariate survival analysis, level of 14F7 Mab immunoreactivity (P = 0.0078), TNM Stage (P = 0.0007) and lymphovascular invasion (0.027) were significant prognostic factors for overall survival. Among these variables, level of 14F7 Mab immunoreactivity (HR = 0.268; 95% CI  0.078–0.920; P = 0.036) and TNM stage (HR = 0.249; 95% CI 0.066–0.932; P = 0.039) were independent prognostic factors on multivariate analysis. Conclusions. This study is the first approach on the prognostic significance of 14F7 Mab immunoreactivity in patients with colon adenocarcinoma and this assessment might be used in the prognostic estimate of CC, although further studies will be required to validate these findings.

New Approaches in Immunotherapy for the Treatment of Lung Cancer

Despite the several advances in the last few years into treatment of advanced lung cancer, the 5-year survival remains extremely low. New therapeutic strategies are currently under investigation, and immunotherapy seems to offer a promising treatment alternative. In the last decade, therapeutic cancer vaccines in lung cancer have been rather disappointing, mainly due to the lack of efficient predictive biomarkers. A better refinement of the patient population that might respond to treatment might finally lead to a success story. For the first time, the immune checkpoint inhibitors are demonstrating sustained antitumor response and improved survival and they may be the first immunotherapeutics available for patients with lung cancer.

Glycosylation of glycolipids in cancer: basis for development of novel therapeutic approaches

Altered networks of gene regulation underlie many pathologies, including cancer. There are several proteins in cancer cells that are turned either on or off, which dramatically alters the metabolism and the overall activity of the cell, with the complex machinery of enzymes involved in the metabolism of glycolipids not being an exception. The aberrant glycosylation of glycolipids on the surface of the majority of cancer cells, associated with increasing evidence about the functional role of these molecules in a number of cellular physiological pathways, has received considerable attention as a convenient immunotherapeutic target for cancer treatment. This has resulted in the development of a substantial number of passive and active immunotherapies, which have shown promising results in clinical trials. More recently, antibodies to glycolipids have also emerged as an attractive tool for the targeted delivery of cytotoxic agents, thereby providing a rationale for future therapeutic interventions in cancer. This review first summarizes the cellular and molecular bases involved in the metabolic pathway and expression of glycolipids, both in normal and tumor cells, paying particular attention to sialosylated glycolipids (gangliosides). The current strategies in the battle against cancer in which glycolipids are key players are then described.

The dark side of dendritic cells: development and exploitation of tolerogenic activity that favor tumor outgrowth and immune escape

Dendritic cells (DC) play a central role in the regulation of the immune responses by providing the information needed to decide between tolerance, ignorance, or active responses. For this reason different therapies aim at manipulating DC to obtain the desired response, such as enhanced cell-mediated toxicity against tumor and infected cells or the induction of tolerance in autoimmunity and transplantation. In the last decade studies performed in these settings have started to identify (some) molecules/factors involved in the acquisition of a tolerogenic DC phenotype as well as the underlying mechanisms of their regulatory function on different immune cell populations.

Immunoreactivity of the 14F7 Mab Raised against N-Glycolyl GM3 Ganglioside in Primary Lymphoid Tumors and Lymph Node Metastasis

The reactivity of the 14F7 Mab, a highly specific IgG1 against N-glycolyl GM3 ganglioside (NeuGcGM3) in normal tissues, lymphomas, lymph node metastasis, and other metastatic sites was assessed by immunohistochemistry. In addition, the effect of chemical fixation on the 14F7 Mab staining using monolayers of P3X63Ag.653 cells was also evaluated. Moreover, the ability of 14F7 to bind NeuGcGM3 ganglioside inducing complement-independent cytotoxicity by a flow cytometry-based assay was measured. The 14F7 Mab was reactive in unfixed, 4% paraformaldehyde, 4% formaldehyde, and acetone fixed cells. Postfixation with acetone did not alter the localization of NeuGcGM3, while the staining with 14F7 Mab was significantly eliminated in both cells fixed and postfixed with methanol but only partially reduced with ethanol. The staining with 14F7 Mab was evidenced in the 89.2%, 89.4%, and 88.9% of lymphomas, lymph node metastasis, and other metastatic sites, respectively, but not in normal tissues. The treatment with 14F7 Mab affected both morphology and membrane integrity of P3X63Ag.653 cells. This cytotoxic activity was dose-dependent and ranged from 24.0 to 84.7% (10-1000  μ g/mL) as compared to the negative control. Our data could support the possible use of NeuGcGM3 as target for both active and passive immunotherapy against malignancies expressing this molecule.

Human antibodies reactive to NeuGcGM3 ganglioside have cytotoxic antitumor properties

N-glycolylated gangliosides are not naturally expressed in healthy human tissues but are overexpressed in several tumors. We demonstrate the existence of antibodies that bind (N-glycolylneuraminyl)-lactosylceramide (NeuGcGM3) and are detectable in the sera of 65 from the 100 donors (65%) tested by ELISA. From those 65 NeuGcGM3 antibody-positive donors, 35 had antibodies that were able to recognize and kill NeuGcGM3-expressing tumor cells by a complement-mediated mechanism. After complement inactivation, 11 of the 35 positive sera showed a direct cytotoxic effect on the tumor cells. This complement-independent cytotoxicity was dependent on the presence of antigen on the membrane and resembles an oncotic necrosis cell death. Both the levels of anti-NeuGcGM3 antibodies in the sera as well as the percentage of healthy donors with this immunity decreased with the age of the donor. In contrast to age and gender-matched healthy donors, we could only detect low reactivity against NeuGcGM3 in the sera of six out of 53 non-small cell lung cancer patients. These results suggest the existence of antibodies against NeuGcGM3 with antitumor immune surveillance functions, reinforcing the importance of N-glycolylated gangliosides as antitumor targets.

Anti-ganglioside antibodies induced in chickens by an alum-adsorbed anti-idiotype antibody targeting NeuGcGM3

Racotumomab is a murine anti-idiotype cancer vaccine targeting NeuGcGM3 on melanoma, breast, and lung cancer. In order to characterize the immunogenicity of alum-adsorbed racotumomab in a non-clinical setting, Leghorn chickens were immunized in dose levels ranging from 25 μg to 1600 μg. Racotumomab was administered subcutaneously in the birds' neck with three identical boosters and serum samples were collected before, during and after the immunization schedule. A strong antibody response was obtained across the evaluated dose range, confirming the immunogenicity of racotumomab even at dose levels as low as 25 μg. As previously observed when using Freund's adjuvant, alum-adsorbed racotumomab induced an idiotype-specific response in all the immunized birds and ganglioside-specific antibodies in 60–100% of the animals. In contrast to the rapid induction anti-idiotype response, detection of ganglioside-specific antibodies in responsive animals may require repeated boosting. Kinetics of anti-NeuGcGM3 antibody titers showed a slight decline 2 weeks after each booster, arguing in favor of repeated immunizations in order to maintain antibody titer. Interestingly, the intensity of the anti-NeuGcGM3 response paralleled that of anti-mucin antibodies and anti-tumor antibodies, suggesting that the in vitro detection of anti-ganglioside antibodies might be a surrogate for an in vivo activity of racotumomab. Taken together, these results suggest that Leghorn chicken immunization might become the means to test the biological activity of racotumomab intended for clinical use.

Tissue Reactivity of the 14F7 Mab Raised against N-Glycolyl GM3 Ganglioside in Tumors of Neuroectodermal, Mesodermal, and Epithelial Origin

The expression of N-glycolylneuraminic acid forming the structure of gangliosides and/or other glycoconjugates (Hanganutziu-Deicher antigen) in human has been considered as a tumor-associated antigen. Specifically, some reports of 14F7 Mab (a highly specific Mab raised against N-glycolyl GM3 ganglioside) reactivity in human tumors have been recently published. Nevertheless, tumors of epithelial origin have been mostly evaluated. The goal of the present paper was to evaluate the immunohistochemical recognition of 14F7 Mab in different human tumors of neuroectodermal, mesodermal, and epithelial origins using an immunoperoxidase staining method. Samples of fetal, normal, and reactive astrocytosis of the brain were also included in the study. In general, nontumoral tissues, as well as, low-grade brain tumors showed no or a limited immunoreaction with 14F7 Mab. Nevertheless, high-grade astrocytomas (III-IV) and neuroblastomas, as well as, sarcomas and thyroid carcinomas were mostly reactive with 14F7. No reaction was evidenced in medulloblastomas and ependymoblastomas. Our data suggest that the expression of N-glycolyl GM3 ganglioside could be related to the aggressive behavior of malignant cells, without depending on the tumor origin. Our data could also support the possible use of N-glycolyl GM3 as a target for both active and passive immunotherapies of malignancies expressing this molecule.

Preclinical evaluation of racotumomab, an anti-idiotype monoclonal antibody to N-glycolyl-containing gangliosides, with or without chemotherapy in a mouse model of non-small cell lung cancer

N-glycolylneuraminic acid (NeuGc) is a sialic acid molecule usually found in mammalian cells as terminal constituents of different membrane glycoconjugates such as gangliosides. The NeuGcGM3 ganglioside has been described as a tumor antigen for non-small cell lung cancer (NSCLC) in humans. Racotumomab is an anti-NeuGc-containing gangliosides anti-idiotype monoclonal antibody (mAb) (formerly known as 1E10) that has received attention as a potential active immunotherapy for advanced lung cancer in clinical trials. In this work, we have examined the antitumor activity of racotumomab in combination or not with chemotherapy, using the 3LL Lewis lung carcinoma as a preclinical model of NSCLC in C57BL/6 mice. Vaccination with biweekly doses of racotumomab at 50-200 μg/dose formulated in aluminum hydroxide (racotumomab-alum vaccine) demonstrated a significant antitumor effect against the progression of lung tumor nodules. Racotumomab-alum vaccination exerted a comparable effect on lung disease to that of pemetrexed-based chemotherapy (100 mg/kg weekly). Interestingly, chemo-immunotherapy was highly effective against lung nodules and well-tolerated, although no significant synergistic effect was observed as compared to each treatment alone in the present model. We also obtained evidence on the role of the exogenous incorporation of NeuGc in the metastatic potential of 3LL cells. Our preclinical data provide support for the combination of chemotherapy with the anti-idiotype mAb racotumomab, and also reinforce the biological significance of NeuGc in lung cancer.

Maintenance treatment with chemotherapy and immunotherapy in non-small cell lung cancer: a case report

A 53-years-old woman was diagnosed with lung adenocarcinoma state IV (synchronous pleural involvement) in April 2009. First-line systemic treatment included six cycles of Carboplatin, Paclitaxel, and Bevacizumab. Partial response was achieved. Maintenance therapy with Bevacizumab and Pemetrexed was given from September 2009 to February 2010. No response changes were observed. Immunotherapy was initiated, and then Pemetrexed was given with the same disease status. Both treatments were well tolerated. Immunotherapy toxicity included reaction at the site of injection grade 2. At present, the patient is still on this treatment. Given the poor prognosis of patients with advanced lung cancer, the combination of both treatments during the stable phase of the disease may improve progression-free survival.

Detection of N-glycolyated gangliosides in non-small-cell lung cancer using GMR8 monoclonal antibody

Gangliosides are glycosphingolipids found on the cell surface. They act as recognition molecules or signal modulators and regulate cell proliferation and differentiation. N-glycolylneuraminic acid (NeuGc)-containing gangliosides have been detected in some neoplasms in humans, although they are usually absent in normal human tissues. Our aim was to evaluate the presence of NeuGc-containing gangliosides including GM3 (NeuGc) and assess their relationship with the prognosis of non-small-cell lung cancer (NSCLC). NeuGc-containing ganglioside expression in NSCLC tissues was analyzed immunohistochemically using the mouse monoclonal antibody GMR8, which is specific for gangliosides with NeuGc alpha 2,3Gal-terminal structures. On the basis of NeuGc-containing ganglioside expression, we performed survival analysis. We also investigated the differences in the effects of GM3 (N-acetylneuraminic acid [NeuAc]) and GM3 (NeuGc) on inhibition of epidermal growth factor receptor (EGFR) tyrosine kinase in A431 cells. As a result, the presence of NeuGc-containing gangliosides was evident in 86 of 93 (93.5%) NSCLC samples. The NSCLC patients with high NeuGc-containing ganglioside expression had a low overall survival rate and a significantly low progression-free survival rate. In the in vitro study, the inhibitory effect of GM3 on EGFR tyrosine kinase in A431 cells after exposure to GM3 (NeuGc) was lower than that after exposure to GM3 (NeuAc). In conclusion, NeuGc-containing gangliosides including GM3 (NeuGc) are widely expressed in NSCLC, and NeuGc-containing ganglioside expression is associated with patient survival. The difference in the effects of GM3 (NeuGc) and GM3 (NeuAc) on the inhibition of EGFR tyrosine kinase might contribute to improvement in the prognosis of NSCLC patients.

Anti-idiotype antibodies in cancer treatment: the pharmaceutical industry perspective

Active immunotherapy is an interesting field from the industry's perspective and in the last years, regulatory agencies and the medical community have showed renewed expectations and interest in cancer vaccines. The development of new immune therapies offers many challenges, and this is reflected in the small number of phase III trials showing clear benefits. Traditional concepts applied in clinical trials for the development of chemotherapeutic agents may be inadequate for immunotherapies and a new paradigm is emerging. It is possible that organized efforts and funding will accelerate the development of therapeutically effective cancer vaccines. This article reviews the attributes of cancer vaccines which make them attractive from the industry's perspective, and focuses especially in the characteristics of Racotumomab, an anti-idiotype antibody vaccine.