Peptide vaccines and targeting HER and VEGF proteins may offer a potentially new paradigm in cancer immunotherapy

VEGF signaling: Role in angiogenesis and beyond

Angiogenesis is a crucial process for tissue development, repair, and tumor survival. Vascular endothelial growth factor (VEGF) is a key driver secreted by cancer cells, promoting neovascularization. While VEGF's role in angiogenesis is well-documented, its influence on the other aspects in tumor microenvironemt is less discussed. This review elaborates on VEGF's impact on intercellular interactions within the tumor microenvironment, including how VEGF affects pericyte proliferation and migration and mediates interactions between tumor-associated macrophages and cancer cells, resulting in PDL-1-mediated immunosuppression and Nrf2-mediated epithelial-mesenchymal transition. The review discusses VEGF's involvement in intra-organelle crosstalk, tumor metabolism, stemness, and epithelial-mesenchymal transition. It also provides insights into current anti-VEGF therapies and their limitations in cancer treatment. Overall, this review aims to provide a thorough overview of the current state of knowledge concerning VEGF signaling and its impact, not only on angiogenesis but also on various other oncogenic processes.

From Anti-HER-2 to Anti-HER-2-CAR-T Cells: An Evolutionary Immunotherapy Approach for Gastric Cancer

Current Therapeutic modalities provide no survival advantage to gastric cancer (GC) patients. Targeting the human epidermal growth factor receptor-2 (HER-2) is a viable therapeutic strategy against advanced HER-2 positive GC. Antibody-drug conjugates, small-molecule tyrosine kinase inhibitors (TKIs), and bispecific antibodies are emerging as novel drug forms that may abrogate the resistance to HER-2-specific drugs and monoclonal antibodies. Chimeric antigen receptor-modified T cells (CAR-T) targeting HER-2 have shown considerable therapeutic potential in GC and other solid tumors. However, due to the high heterogeneity along with the complex tumor microenvironment (TME) of GC that often leads to immune escape, the immunological treatment of GC still faces many challenges. Here, we reviewed and discussed the current progress in the research of anti-HER-2-CAR-T cell immunotherapy against GC.

ERBB Signaling Pathway in Cancer Stem Cells

The epidermal growth factor receptor (EGFR) was first tyrosine kinase receptor linked to human cancers. EGFR or ERBB1 is a member of ERBB subfamily, which consists of four type I transmembrane receptor tyrosine kinases, ERBB1, 2, 3 and 4. ERBBs form homo/heterodimers after ligand binding except ERBB2 and consequently becomes activated. Different signal pathways, such as phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT), RAS/RAF/MEK/ERK, phospholipase Cγ and JAK-STAT, are triggered by ERBB activation. Since ERBBs, through these pathways, regulate stemness and differentiation of cancer stem cells (CSCs), their roles in CSC tumorigenicity have extensively been investigated. The hyperactivation of ERBBs and its downstream pathways stimulated by either genetic and/or epigenetic factors are frequently described in many types of human cancers. Their dysregulations make cells acquiring CSC characters such as survival, tumorigenicity and stemness. Because of the roles in tumor growth and progress, ERBBs are considered to be one of the drug targets as cancer treatment strategy. In this chapter, we will summarize the structure, function and roles of ERBB subfamily along with their relative pathways regulating the stemness and tumorigenicity of CSCs. Finally, we will discuss the targeting therapy strategies of cancer along with ERBBs in addition to some challenges and future perspectives.

Advancements in Human Breast Cancer Targeted Therapy and Immunotherapy

Human breast cancer treatment regimens have evolved greatly due to the significant advances in understanding the molecular mechanisms and pathways of the common subtypes of breast cancer. In this review, we discuss recent progress in breast cancer targeted therapy and immunotherapy as well as ongoing clinical trials. We also highlight the potential of combination therapies and personalized approaches to improve clinical outcomes. Targeted therapies have surpassed the hormone receptors and the human epidermal growth factor receptor 2 (HER2) to include many other molecules in targetable pathways such as the epidermal growth factor receptor (EGFR), poly (adenosine diphosphate-ribose) polymerase (PARP), and cyclin-dependent kinase 4/6 (CDK4/6). However, resistance to targeted therapy persists, underpinning the need for more efficacious therapies. Immunotherapy is considered a milestone in breast cancer treatments, including the engineered immune cells (CAR-T cell therapy) to better target the tumor cells, vaccines to stimulate the patient's immune system against tumor antigens, and checkpoint inhibitors (PD-1, PD-L1, and CTLA4) to block molecules that mediate immune inhibition. Targeted therapies and immunotherapy tested in breast cancer clinical trials are discussed here, with special emphasis on combinatorial approaches which are believed to maximize treatment efficacy and enhance patient survival.

Recent Applications of Retro-Inverso Peptides

Natural and de novo designed peptides are gaining an ever-growing interest as drugs against several diseases. Their use is however limited by the intrinsic low bioavailability and poor stability. To overcome these issues retro-inverso analogues have been investigated for decades as more stable surrogates of peptides composed of natural amino acids. Retro-inverso peptides possess reversed sequences and chirality compared to the parent molecules maintaining at the same time an identical array of side chains and in some cases similar structure. The inverted chirality renders them less prone to degradation by endogenous proteases conferring enhanced half-lives and an increased potential as new drugs. However, given their general incapability to adopt the 3D structure of the parent peptides their application should be careful evaluated and investigated case by case. Here, we review the application of retro-inverso peptides in anticancer therapies, in immunology, in neurodegenerative diseases, and as antimicrobials, analyzing pros and cons of this interesting subclass of molecules.

Correlation Between Vascular Endothelial Growth Factor and Long-Term Occurrence of HCV-Related Hepatocellular Carcinoma After Treatment with Direct-Acting Antivirals

We aimed to evaluate the correlation between vascular endothelial growth factor (VEGF) and long-term occurrence of hepatocellular carcinoma after HCV treatment with direct-acting antivirals (DAAs) and the HCC stage. Two groups with HCV-related liver cirrhosis and HCC were included: group 1, HCC following DAAs; group 2, HCC did not receive DAAs. The serum level of VEGF and HCC staging was evaluated. The duration between DAAs and HCC was 21.81 ± 11.66 months. Portal vein thrombosis (PVT) was observed more in group 1 (31%). VEGF was relatively elevated in group 1 compared to group 2. HCC patients after DAAs, showed elevated VEGF with frequent PVT.

Anticancer Effects of Tacrolimus on Induced Hepatocellular Carcinoma in Mice

BACKGROUND

Tacrolimus is a calcineurin inhibitor widely used for immunological disorders. However, there is a significant controversy regarding its effect on the liver. The present study was conducted to evaluate the anticancer effects of tacrolimus on an induced murine hepatocellular carcinoma (HCC) model and its possible hepatotoxicity at standard therapeutic doses.

METHODS

Fifty-four male mice were divided into five groups: a control healthy group, control HCC group, tacrolimus-treated group, doxorubicin (DOXO)-treated group, and combined tacrolimus- and DOXO-treated group. The activity of liver enzymes, including alkaline phosphatase, gamma-glutamyl transferase, lactate dehydrogenase, alanine transaminase, and aspartate transaminase, was determined. Serum vascular endothelial growth factor (VEGF) was measured using an enzyme-linked immunosorbent assay. A quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to measure the expression of proliferating cell nuclear antigen (PCNA), Bax, and p53 mRNA. Immunohistochemical staining for cyclin D1 and VEGF was performed.

RESULTS

Mice that received combined treatment with tacrolimus and DOXO exhibited the best improvement in all parameters when compared with the groups that received DOXO or tacrolimus alone (p < 0.001).

CONCLUSION

The combination of DOXO and tacrolimus was more effective in the management of HCC compared with either agent alone. This improvement was detected by the reduction of liver enzymes and the improvement of the histopathological picture. The involved mechanisms included significant apoptosis induction demonstrated by upregulation of bax along with a reduction in angiogenesis demonstrated by downregulation of VEGF. This was accompanied by inhibition of cell cycle progression mediated by upregulated p53 and downregulated PCNA and cyclin D1.

B-cell epitope peptide cancer vaccines: a new paradigm for combination immunotherapies with novel checkpoint peptide vaccine

In light of the numerous US FDA-approved humanized monoclonal antibodies (mAbs) for cancer immunotherapy, it is surprising that the advancement of B-cell epitope vaccines designed to elicit a natural humoral polyclonal antibody response has not gained traction in the immune-oncology landscape. Passive immunotherapy with humanized mAbs (Trastuzumab [Herceptin®]; Pertuzumab [Perjeta®]) has provided clinical benefit to breast cancer patients, albeit with significant shortcomings including toxicity problems and resistance, high costs, sophisticated therapeutic regimen and long half-life. The role of B-cell humoral immunity in cancer is under appreciated and underdeveloped. We have advanced the idea of active immunotherapy with chimeric B-cell epitope peptides incorporating a 'promiscuous' T-cell epitope that elicits a polyclonal antibody response, which provides safe, cost-effective therapeutic advantage over mAbs. We have created a portfolio of validated B-cell peptide epitopes against multiple receptor tyrosine kinases (HER-1, HER-3, IGF-1R and VEGF). We have successfully translated two HER-2 combination B-cell peptide vaccines in Phase I and II clinical trials. We have recently developed an effective novel PD-1 vaccine. In this article, I will review our approaches and strategies that focus on B-cell epitope cancer vaccines.

Design of Anti-Angiogenic Peptidomimetics and Evaluation their Biological Activity by In Vitro Assays

BACKGROUND

One of the important therapeutic approaches in cancer field is development of compounds which can block the initial tumor growth and the progression of tumor metastasis with no side effects. Thus, the recent study was carried out to design anti-VEGFR2-peptidomimetics as the most significant factor of angiogenesis process- and evaluate their biological activity by in vitro assays.

METHODS

We designed anti-VEGFR2 peptidomimetics with anti-angiogenic activity, including compound P (lactam derivative) and compound T (indole derivative) by using in silico methods. Then, the inhibitory activity on angiogenesis was evaluated by using angiogenesis specific assays such as Human Umbilical Vein Endothelial Cell (HUVEC) proliferation, tube formation in Matrigel, MTT and Real-Time PCR. IC50 values of the compounds were also determined by cytotoxicity plot in MTT assay.

RESULTS

Compounds P and T inhibited HUVEC cell proliferation and viability in a dose-dependent manner. The IC50 for compound T and compound P in HUVEC cell line were 113 and 115 μg/ml, respectively. Tube formation assay revealed that both compounds can inhibit angiogenesis effectively. The results of Real-Time PCR also showed these compounds are able to inhibit the expression of CD31 gene in HUVEC cell line.

CONCLUSION

Our study suggested that compounds P and T may act as therapeutic molecules, or lead compounds for development of angiogenesis inhibitors in VEGF-related diseases.

Combination therapy of hepatocellular carcinoma by DNA shuffling-based VEGF vaccine and doxorubicin

Antiangiogenic therapy can enhance the efficacy of chemotherapy against solid tumors. This study was to determine whether TT46, a potential VEGF vaccine from DNA shuffling with a helper T-cell epitope of tetanus toxin B subunit, could enhance the efficacy of doxorubicin to combat hepatocellular carcinoma (HCC). Compared with monotherapy, the combination with TT46 vaccination and doxorubicin could significantly reduce microvessel counts and inhibit tumor angiogenesis. Enhanced immunization with TT46 for total six doses could induce long-term response maintenance with high anti-VEGF antibody titers in body. As a result, the combination with enhanced TT46 vaccination and doxorubicin significantly inhibited the HCC growth, and improved the survival rate of HCC-bearing mice in both of subcutaneous tumor model and lung metastasis model. In conclusion, the combined therapy with TT46 vaccination and doxorubicin has antitumor effects in both a prophylactic and therapeutic setting in a mouse model of H22 hepatocellular carcinoma.

Targeting the pro-angiogenic forms of VEGF or inhibiting their expression as anti-cancer strategies

Tumor growth relies on oxygen and blood supply depending on neo-vascularization. This process is mediated by the Vascular Endothelial Growth Factor (VEGF) in many tumors. This paradigm has led to the development of specific therapeutic approaches targeting VEGF or its receptors. Despite their promising effects, these strategies have not improved overall survival of patients suffering from different cancers compared to standard therapies. We hypothesized that the existence of anti-angiogenic forms of VEGF VEGFxxxb which are still present in many tumors limit the therapeutic effects of the anti-VEGF antibodies bevacizumab/Avastin (BVZ). To test this hypothesis, we generated renal cell carcinoma cells (RCC) expressing VEGF165b. The incidence of tumors xenografts generated in nude mice and their growth were inferior to those obtained with control cells. Whereas BVZ had no effect on control tumors, it slowed-down the growth of tumor generated with VEGF165b expressing cells. A prophylactic immunization against the domain discriminating VEGF from VEGFxxxb isoforms inhibited the growth of tumor generated with two different syngenic tumor cell lines (melanoma (B16 cells) and RCC (RENCA cells)). Purified immunoglobulins from immunized mice also slowed-down tumor growth of human RCC xenografts in nude mice, producing a potent effect compared to BVZ in this model. Furthermore, down-regulating the serine-arginine-rich splicing factor 1 (SRSF1) or masking SRSF1 binding sites by 2'O-Methyl RNA resulted in the increase of the VEGFxxxb/VEGF ratio. Therefore, a vaccine approach, specific antibodies against pro-angiogenic forms of VEGF, or increasing the VEGFxxxb/VEGF ratio may represent new prophylactic or pro-active anti-cancer strategies.

Molecular property diagnostic suite (MPDS): Development of disease-specific open source web portals for drug discovery

Molecular property diagnostic suite (MPDS) is a Galaxy-based open source drug discovery and development platform. MPDS web portals are designed for several diseases, such as tuberculosis, diabetes mellitus, and other metabolic disorders, specifically aimed to evaluate and estimate the drug-likeness of a given molecule. MPDS consists of three modules, namely data libraries, data processing, and data analysis tools which are configured and interconnected to assist drug discovery for specific diseases. The data library module encompasses vast information on chemical space, wherein the MPDS compound library comprises 110.31 million unique molecules generated from public domain databases. Every molecule is assigned with a unique ID and card, which provides complete information for the molecule. Some of the modules in the MPDS are specific to the diseases, while others are non-specific. Importantly, a suitably altered protocol can be effectively generated for another disease-specific MPDS web portal by modifying some of the modules. Thus, the MPDS suite of web portals shows great promise to emerge as disease-specific portals of great value, integrating chemoinformatics, bioinformatics, molecular modelling, and structure- and analogue-based drug discovery approaches.

Combined immunotherapy of breast cancer with EGF and VEGF vaccines from DNA shuffling in a mouse model

AIM

Development of EGF and VEGF vaccines with high antigenicity for combined immunotherapy of EGF-EGFR signaling-dependent epithelial tumors such as breast cancer.

METHOD

EGF genes from mouse, human and chicken were randomly assembled to chimeric genes by DNA shuffling, then a chimeric EGF was selected out by PCR, SDS-PAGE and immunization for combined immunotherapy of breast cancer with a previously constructed chimeric VEGF vaccine from shuffling.

RESULTS

Combined vaccination with chimeric EGF and VEGF from shuffling could induce high titer of antibodies against EGF and VEGF to inhibit tumor growth and angiogenesis, and improve the survival rate of mice with breast cancer.

CONCLUSION

Combined vaccination with EGF and VEGF from shuffling showed better immunotherapy on EGF-EGFR signaling-dependent epithelial tumors such as breast cancer than the single-agent EGF vaccination.

Targeted therapies in breast cancer: New challenges to fight against resistance

Breast cancer is the most common type of cancer found in women and today represents a significant challenge to public health. With the latest breakthroughs in molecular biology and immunotherapy, very specific targeted therapies have been tailored to the specific pathophysiology of different types of breast cancers. These recent developments have contributed to a more efficient and specific treatment protocol in breast cancer patients. However, the main challenge to be further investigated still remains the emergence of therapeutic resistance mechanisms, which develop soon after the onset of therapy and need urgent attention and further elucidation. What are the recent emerging molecular resistance mechanisms in breast cancer targeted therapy and what are the best strategies to apply in order to circumvent this important obstacle? The main scope of this review is to provide a thorough update of recent developments in the field and discuss future prospects for preventing resistance mechanisms in the quest to increase overall survival of patients suffering from the disease.

Association of VEGFA polymorphisms with susceptibility and clinical outcome of hepatocellular carcinoma in a Chinese Han population

Vascular endothelial growth factor A (VEGFA) is an important angiogenesis regulator, which plays an important role in angiogenesis and progression of tumor, including hepatocellular carcinoma (HCC). We aimed at determining whether single nucleotide polymorphisms of VEGFA gene influence the development and clinical outcomes of HCC. We analyzed four potential functional polymorphisms (936C/T, 634G/C, 1612G/A, 2578C/A) of VEGFA gene in 476 HCC patients and 526 controls using matrix-assisted laser desorption ionization time-of-flight mass spectrometry method. Serum VEGF levels were measured by enzyme-linked immunosorbent assay. The Kaplan-Meier methods with log-rank test and Cox regression models were used to compare survival of resected HCC patients according to the genotype. We found that only the VEGFA 2578C/A polymorphism was significantly associated with decreased risk of HCC (AA/AC vs. CC; adjusted OR = 0.69, 95% CI = 0.51-0.93). Furthermore, the 2578C/A polymorphism was associated with significantly decreased postoperative recurrence (AA/AC vs. CC, adjusted OR = 0.51; 95% CI, 0.29-0.88) and improved overall survival (AA/AC vs. CC, adjusted HR = 0.27, 95% CI = 0.13-0.52) of resected HCC patients. In addition, the VEGF serum levels in HCC patients were significantly higher than those in healthy controls, although no significant association between VEGFA genotype and serum levels of VEGF was observed. These results suggest that the VEGFA 2578 C/A polymorphism may play a potential role in the development and clinical outcome of HCC among Chinese Han population.

Inhibition of cell adhesion and immune responses in the mouse model of collagen-induced arthritis with a peptidomimetic that blocks CD2-CD58 interface interactions

CD2 and CD58 are two important costimulatory molecules involved in generating the signal II required for normal immune signaling. However, this interaction can be targeted to be of benefit in cases of abnormal immune signaling seen in autoimmune diseases. Our objective in this study was to design a peptidomimetic (compound 7) based on a β-strand structure of the adhesion domain of CD2 protein to inhibit CD2-CD58 protein-protein interaction and its effect on immunomodulation in the collagen-induced arthritis (CIA) model. The ability of compound 7 to bind to CD58 protein was assessed using flow cytometry. The effect of compound 7 on modulating the immune response was evaluated in an autoimmune disease using CIA in mice. The stability of compound 7 was evaluated in mouse serum using mass spectrometry. Antibody (Ab) binding inhibition studies suggested that compound 7 binds to CD58 protein. Compound 7 was successful in modulating immune responses when administered in the CIA mouse model along with reducing anti-collagen Ab levels and decreasing the level of interferon gamma (IFN-γ) relative to control treatments. Compound 7 was found to be nonimmunogenic and stable in mouse serum up to 48 h. Results suggest that compound 7 can serve as a lead compound for immunomodulation, and could be a therapeutic agent for the autoimmune disease rheumatoid arthritis (RA).

Clinical applications of mouse models for breast cancer engaging HER2/neu

Human c-ErbB2 (HER2) has long been used as a marker of breast cancer (BC) for sub-categorization for the prediction of prognosis, and determination of therapeutic strategies. HER2 overexpressing BCs are more invasive/metastatic; but patients respond to monoclonal antibody therapy with trastuzumab or tyrosine kinase inhibitors, at least at early stages. To date, numerous mouse models that faithfully reproduce HER2(+) BCs have been created in mice. We recently reviewed different mouse models of BC overexpressing wild type or mutant neu driven by MMTV, neu, or doxycycline-inducible promoters. These mice have been used to demonstrate the histopathology, oncogenic signaling pathways initiated by aberrant overexpression of HER2 in the mammary epithelium, and interaction between oncogenes and tumor suppressor genes at molecular levels. In this review, we focus on their clinical applications. They can be used to test the efficacy of HER(2) inhibitors before starting clinical trials, characterize the tumor-initiating cells that could be the cause of relapse after therapy as well as to analyze the molecular mechanisms of therapeutic resistance targeting HER2. MMTV-human ErbB2 (HER2) mouse models have recently been established since the monoclonal antibody to HER2 (trastuzumab; Herceptin®) does not recognize the rat neu protein. It has been reported that early intervention with HER2 monoclonal antibody would be beneficial for preventing mammary carcinogenesis. MDA-7/IL-24 as well as naturally-occurring chemicals have also been tested using MMTV-neu models. Recent studies have shown that MMTV-neu models are useful to develop vaccines to HER2 for immunotherapy. The mouse models employing HER2/neu will be essential for future antibody or drug screenings to overcome resistance to trastuzumab or HER(2)-specific tyrosine kinase inhibitors.

A paradigm shift: Cancer therapy with peptide-based B-cell epitopes and peptide immunotherapeutics targeting multiple solid tumor types: Emerging concepts and validation of combination immunotherapy

There is a recognizable and urgent need to speed the development and application of novel, more efficacious anti-cancer vaccine therapies that inhibit tumor progression and prevent acquisition of tumor resistance. We have created and established a portfolio of validated peptide epitopes against multiple receptor tyrosine kinases and we have identified the most biologically effective combinations of EGFR (HER-1), HER-2, HER-3, VEGF and IGF-1R peptide vaccines/mimics to selectively inhibit multiple receptors and signaling pathways. The strategy is based on the use of chimeric conformational B-cell epitope peptides incorporating "promiscuous" T-cell epitopes that afford the possibility of generating an enduring immune response, eliciting protein-reactive high-affinity anti-peptide antibodies as potential vaccines and peptide mimics that act as antagonists to receptor signaling that drive cancer metastasis. In this review we will summarize our ongoing studies based on the development of combinatorial immunotherapeutic strategies that act synergistically to enhance immune-mediated tumor killing aimed at addressing mechanisms of tumor resistance for several tumor types.

Effects of vascular endothelial growth factor expression on pathological characteristics and prognosis of osteosarcoma

Vascular endothelial growth factor (VEGF) has been linked with tumor invasion and metastasis. However, the role of VEGF expression in osteosarcoma remains controversial. By searching the PubMed, Embase, and Google Scholar databases, we conducted a meta-analysis to evaluate the pathological and prognostic significance of VEGF in osteosarcoma. Studies were pooled, and the odds ratio (OR) and its corresponding 95 % confidence interval (CI) were calculated. Nine relevant articles were included in this meta-analysis study. We performed pooled analysis with available data on the association between VEGF expression and age, gender, tumor stages IIB-III versus I-IIA, tumor recurrence, response to chemotherapy, and tumor metastasis. Our results revealed that VEGF expression might be closely associated with metastasis of osteosarcoma (OR 4.74, 95 % CI 2.53-8.87, P < 0.001). Furthermore, our findings also demonstrated that patients with grade IIB-III osteosarcoma showed a higher frequency of VEGF expression than those with grade I-IIA osteosarcoma (OR 5.33, 95 % CI 2.03-13.98, P = 0.001). We failed to find the association between VEGF expression and age (OR 0.82, 95 % CI 0.44-1.53, P = 0.539), gender (OR 1.33, 95 % CI 0.52-3.42, P = 0.553), tumor recurrence (OR 1.47, 95 % CI 0.56-3.86, P = 0.429), and response to chemotherapy (OR 1.26, 95 % CI 0.14-11.72, P = 0.839). In conclusion, VEGF is related to the grade and metastasis of osteosarcoma. It may play a significant role in clinical guidelines for the treatment and prognostic evaluation.

Peptides and peptidomimetics as immunomodulators

Peptides and peptidomimetics can function as immunomodulating agents by either blocking the immune response or stimulating the immune response to generate tolerance. Knowledge of B- or T-cell epitopes along with conformational constraints is important in the design of peptide-based immunomodulating agents. Work on the conformational aspects of peptides, synthesis and modified amino acid side chains have contributed to the development of a new generation of therapeutic agents for autoimmune diseases and cancer. The design of peptides/peptidomimetics for immunomodulation in autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, systemic lupus and HIV infection is reviewed. In cancer therapy, peptide epitopes are used in such a way that the body is trained to recognize and fight the cancer cells locally as well as systemically.

Soluble production and function of vascular endothelial growth factor/basic fibroblast growth factor complex peptide

Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are important proangiogenic factors in tumor procession. The autocrine and paracrine bFGF and the VEGF in tumor tissue can promote tumor angiogenesis, tumor growth, and metastasis. A VEGF/bFGF Complex Peptide (VBP3) was designed on the basis of epitope peptides from both VEGF and bFGF to elicit in vivo production of anti-bFGF and anti-VEGF antibodies. In this study, we reported on the production of recombinant VBP3 using high cell density fermentation. Fed-batch fermentation for recombinant VBP3 production was conducted, and the production procedure was optimized in a 10-L fermentor. The fraction of soluble VBP3 protein obtained reached 78% of total recombinant protein output under fed-batch fermentation. Purified recombinant VBP3 could inhibit tumor cell proliferation in vitro and stimulate C57BL/6 mice to produce high titer anti-VEGF and anti-bFGF antibodies in vivo. A melanoma-grafted mouse model and an immunohistochemistry assay showed that tumor growth and tumor angiogenesis were significantly inhibited in VBP3-vaccinated mice. These results demonstrated that soluble recombinant VBP3 could be produced by large-scale fermentation, and the product, with good immunogenicity, elicited production of high-titer anti-bFGF and anti-VEGF antibodies, which could be used as a therapeutic tumor vaccine to inhibit tumor angiogenesis and tumor growth.

IGF-1R peptide vaccines/mimics inhibit the growth of BxPC3 and JIMT-1 cancer cells and exhibit synergistic antitumor effects with HER-1 and HER-2 peptides

The insulin-like growth factor-1 receptor (IGF-1R) plays a crucial role in cellular growth, proliferation, transformation, and inhibition of apoptosis. A myriad of human cancer types have been shown to overexpress IGF-1R, including breast and pancreatic adenocarcinoma. IGF-1R signaling interferes with numerous receptor pathways, rendering tumor cells resistant to chemotherapy, anti-hormonal therapy, and epidermal growth factor receptor (EGFR, also known as HER-1) and v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2, (ERBB2, best known as HER-2) -targeted therapies. Targeting the IGF:IGF-1R axis with innovative peptide inhibitors and vaccine antibodies thus represents a promising therapeutic strategy to overcome drug resistance and to provide new avenues for individualized and combinatorial treatment strategies. In this study, we designed, synthesized, and characterized several B-cell epitopes from the IGF-1:IGF-1R axis. The chimeric peptide epitopes were highly immunogenic in outbred rabbits, eliciting high levels of peptide vaccine antibodies. The IGF-1R peptide antibodies and peptide mimics inhibited cell proliferation and receptor phosphorylation, induced apoptosis and antibody-dependent cellular cytotoxicity (ADCC), and significantly inhibited tumor growth in the transplantable BxPC-3 pancreatic and JIMT-1 breast cancer models. Our results showed that the peptides and antibodies targeting residues 56-81 and 233-251 are potential therapeutic and vaccine candidates for the treatment of IGF-1R-expressing cancers, including those that are resistant to the HER-2-targeted antibody, trastuzumab. Additionally, we found additive antitumor effects for the combination treatment of the IGF-1R 56-81 epitope with HER-1-418 and HER-2-597 epitopes. Treatment with the IGF-1R/HER-1 or IGF-1R/HER-2 combination inhibited proliferation, invasion, and receptor phosphorylation, and induced apoptosis and ADCC, to a greater degree than single agents.

Comprehensive profiling of EGFR/HER receptors for personalized treatment of gynecologic cancers

The primary gynecologic cancers include cancers of the endometrium, ovary, and cervix. Worldwide, cervical cancer is the most common gynecologic cancer, whereas endometrial cancer is the most common in the US. Ovarian cancer is the fifth most deadly cancer in women, with 5-year survival rates for advanced disease at only 27 %. As such, there is an urgent need for reliable screening tools and novel targeted therapeutic regimens for these malignancies. The epidermal growth factor receptor (EGFR)/human EGFR (HER) family of receptors has been associated with the development and progression of many solid tumors. Despite clear roles for these receptors in other cancers, the expression of HER family members in gynecologic cancers and their relationship with disease stage, grade, and response to treatment remain controversial. In this review, we describe the existing evidence for the use of HER family members as diagnostic and prognostic indicators as well as their potential as therapeutic targets in gynecologic cancers.

Tumor imaging and targeting potential of an Hsp70-derived 14-mer peptide

BACKGROUND

We have previously used a unique mouse monoclonal antibody cmHsp70.1 to demonstrate the selective presence of a membrane-bound form of Hsp70 (memHsp70) on a variety of leukemia cells and on single cell suspensions derived from solid tumors of different entities, but not on non-transformed cells or cells from corresponding 'healthy' tissue. This antibody can be used to image tumors in vivo and target them for antibody-dependent cellular cytotoxicity. Tumor-specific expression of memHsp70 therefore has the potential to be exploited for theranostic purposes. Given the advantages of peptides as imaging and targeting agents, this study assessed whether a 14-mer tumor penetrating peptide (TPP; TKDNNLLGRFELSG), the sequence of which is derived from the oligomerization domain of Hsp70 which is expressed on the cell surface of tumor cells, can also be used for targeting membrane Hsp70 positive (memHsp70+) tumor cells, in vitro.

METHODOLOGY/PRINCIPAL FINDINGS

The specificity of carboxy-fluorescein (CF-) labeled TPP (TPP) to Hsp70 was proven in an Hsp70 knockout mammary tumor cell system. TPP specifically binds to different memHsp70+ mouse and human tumor cell lines and is rapidly taken up via endosomes. Two to four-fold higher levels of CF-labeled TPP were detected in MCF7 (82% memHsp70+) and MDA-MB-231 (75% memHsp70+) cells compared to T47D cells (29% memHsp70+) that exhibit a lower Hsp70 membrane positivity. After 90 min incubation, TPP co-localized with mitochondrial membranes in memHsp70+ tumors. Although there was no evidence that any given vesicle population was specifically localized, fluorophore-labeled cmHsp70.1 antibody and TPP preferentially accumulated in the proximity of the adherent surface of cultured cells. These findings suggest a potential association between membrane Hsp70 expression and cytoskeletal elements that are involved in adherence, the establishment of intercellular synapses and/or membrane reorganization.

CONCLUSIONS/SIGNIFICANCE

This study demonstrates the specific binding and rapid internalization of TPP by tumor cells with a memHsp70+ phenotype. TPP might therefore have potential for targeting and imaging the large proportion of tumors (∼50%) that express memHsp70.

Association of the vascular endothelial growth factor -2578C/A polymorphism with cancer risk: A meta-analysis update

The vascular endothelial growth factor (VEGF) -2578C/A polymorphism has been previously reported to be associated with cancer risk; however, the results have been controversial. Therefore, the aim of the present study was to explore the association between the VEGF -2578C/A polymorphism with the cancer risk. A total of 37 case-control studies were identified. The pooled analysis showed that there was no association between VEGF -2578C/A and the risk of cancer, and the odds ratios (ORs) [with the corresponding 95% confidence intervals (95% CIs)] were 0.97 (0.91-1.04) for C vs. A, 0.94 (0.86-1.02) for CC vs. AA, 0.92 (0.80-1.06) for CA vs. AA, 0.96 (0.89-1.03) for CC/CA vs. AA and 0.97 (0.88-1.08) for CC vs. CA/AA. Subgroup analyses according to ethnicity, source of control and type of cancer showed that the VEGF -2578C/A polymorphism is associated with colorectal and lung cancers. Additionally, the polymorphism may decrease the risk of cancer in the Asian population. This VEGF polymorphism was not associated with a risk of cancer for the Caucasian [0.92 (0.76-1.11) for CC vs. AA] and African populations [1.31 (0.67-2.58) for CC vs. AA], and it was not associated with bladder [1.06 (0.74-1.53) for CC/AA] and breast cancers [1.01 (0.90-1.15) for CC/AA]. Therefore, the present meta-analysis indicates that VEGF -2578C/A may only be associated with the risk of colorectal cancer, lung cancer and the Asian population. More studies with larger sample sizes are required to provide more conclusive evidence.

Immunosuppression by co-stimulatory molecules: inhibition of CD2-CD48/CD58 interaction by peptides from CD2 to suppress progression of collagen-induced arthritis in mice

Targeting co-stimulatory molecules to modulate the immune response has been shown to have useful therapeutic effects for autoimmune diseases. Among the co-stimulatory molecules, CD2 and CD58 are very important in the early stages of generation of an immune response. Our goal was to utilize CD2-derived peptides to modulate protein-protein interactions between CD2 and CD58, thereby modulating the immune response. Several peptides were designed based on the structure of the CD58-binding domain of CD2 protein. Among the CD2-derived peptides, peptide 6 from the F and C β-strand region of CD2 protein exhibited inhibition of cell-cell adhesion in the nanomolar concentration range. Peptide 6 was evaluated for its ability to bind to CD58 in Caco-2 cells and to CD48 in T cells from rodents. A molecular model was proposed for binding a peptide to CD58 and CD48 using docking studies. Furthermore, in vivo studies were carried out to evaluate the therapeutic ability of the peptide to modulate the immune response in the collagen-induced arthritis (CIA) mouse model. In vivo studies indicated that peptide 6 was able to suppress the progression of CIA. Evaluation of the antigenicity of peptides in CIA and transgenic animal models indicated that this peptide is not immunogenic.

Gene-gene interaction network analysis of ovarian cancer using TCGA data

BACKGROUND

The Cancer Genome Atlas (TCGA) Data portal provides a platform for researchers to search, download, and analysis data generated by TCGA. The objective of this study was to explore the molecular mechanism of ovarian cancer pathogenesis.

METHODS

Microarray data of ovarian cancer were downloaded from TCGA database, and Limma package in R language was used to identify the differentially expressed genes (DEGs) between ovarian cancer and normal samples, followed by the function and pathway annotations of the DEGs. Next, NetBox software was used to for the gene-gene interaction (GGI) network construction and the corresponding modules identification, and functions of genes in the modules were screened using DAVID.

RESULTS

Our studies identified 332 DEGs, including 146 up-regulated genes which mainly involved in the cell cycle related functions and cell cycle pathway, and 186 down-regulated genes which were enriched in extracellular region par function, and Ether lipid metabolism pathway. GGI network was constructed by 127 DEGs and their significantly interacted 209 genes (LINKERs). In the top 10 nodes ranked by degrees in the network, 5 were LINKERs. Totally, 7 functional modules in the network were selected, and they were enriched in different functions and pathways, such as mitosis process, DNA replication and DNA double-strand synthesis, lipid synthesis processes and metabolic pathways. AR, BRCA1, TFDP1, FOXM1, CDK2, and DBF4 were identified as the transcript factors of the 7 modules.

CONCLUSION

our data provides a comprehensive bioinformatics analysis of genes, functions, and pathways which may be involved in the pathogenesis of ovarian cancer.

Plant viral elongated nanoparticles modified for log-increases of foreign peptide immunogenicity and specific antibody detection

Elongated and flexuous recombinant nanoparticles were derived from Turnip mosaic virus to be used as bioscaffolds for increased peptide immunogenicity and peptide-specific antibody sensing. For this purpose, a 20-amino acid peptide derived from human vascular endothelial growth factor receptor 3 (VEGFR-3) was fused to the N-terminal region of Turnip mosaic virus coat protein (CP) by genetic insertion. The insertion was between codons corresponding to the first and second amino acids of the CP in two versions of a previously reported virus-derived vector. Systemic infections of two genetic constructs were achieved in two different plant hosts. The construct proved stable upon successive passages and generated virus nanoparticles identifiable under the electron microscope. The chimeric structures held the VEGFR-3 peptide. Purified VER3 nanoparticles were used to immunize mice, whose sera showed log increases of antibodies against the VEGFR-3 peptide when compared with mice immunized with peptide alone, thus providing the first quantitative data on the potential of elongated flexuous viruses for peptide immunogenicity increases. Purified VER3 nanoparticles also showed log increases in their ability to detect VER3 antibodies in sera, when used as reagents in ELISA assays, an application also used here for the first time.

Peptide vaccines and peptidomimetics of EGFR (HER-1) ligand binding domain inhibit cancer cell growth in vitro and in vivo

Epidermal growth factor receptor (EGFR) is a validated target for several cancers including lung, colorectal, and certain subtypes of breast cancer. Cetuximab targets ligand binding of EGFR, but major problems like high cost, short t1/2, toxicity, and emergence of resistance are associated with the drug. Immunization with EGFR B cell epitopes will train the immune system to produce specific Abs that can kill cancer cells. Also, therapy with stable, less-expensive, and nontoxic EGFR peptide mimics will block EGFR signaling and inhibit cancer growth. We designed three peptides based on the contact sites between EGF and EGFR. The B cell epitopes were synthesized alone and also linked with the measles virus T cell epitope to produce a chimeric peptide vaccine. The peptide vaccines were immunogenic in both mice and rabbits and Abs raised against the vaccine specifically bound EGFR-expressing cells and recombinant human EGFR protein. The peptide mimics and the anti-peptide Abs were able to inhibit EGFR signaling pathways. Immunization with the peptide vaccine or treatment with the B cell epitopes significantly reduced tumor growth in both transplantable breast and lung cancer models. Immunohistochemical analysis also showed significant reductions in microvascular density and actively dividing cells in the tumor sections after treatment in the FVB/n breast cancer model. The 418-435 B cell epitope was the best candidate both as a vaccine or peptide mimic because it caused significant inhibition in the two mouse models. Our results show that this novel EGFR B cell epitope has great potential to be used as a vaccine or treatment option for EGFR-expressing cancers.

A systematic review of vascular endothelial growth factor expression as a biomarker of prognosis in patients with osteosarcoma

Vascular endothelial growth factor (VEGF) plays an important role in the tumor angiogenesis, and its expression has been supposed to be a biomarker of prognosis in patients with osteosarcoma. There are many studies assessing the prognostic role of VEGF expression in osteosarcoma, and no consistent outcomes are reported. To provide a comprehensive assessment of the prognostic role of VEGF expression, we performed a systematic review and meta-analysis of published studies. We assessed the effect of VEGF expression on the overall survival rate and the disease-free survival rate by calculating the pooled odds ratio (OR) with corresponding 95 % confidence interval (95 %CI). Finally, 12 studies with a total of 559 osteosarcoma patients were included into the systematic review and meta-analysis. Compared with osteosarcoma patients with low or negative VEGF expression, patients with high VEGF expression were obviously associated with lower disease-free survival (OR=0.25, 95 %CI 0.11-0.58, P=0.001, I (2) =56.4 %). In addition, patients with high VEGF expression were obviously associated with lower overall survival (OR=0.22, 95 %CI 0.13-0.35, P<0.001, I (2) =0.0 %). Therefore, the findings from this systematic review suggest that VEGF expression is an effective biomarker of prognosis in patients with osteosarcoma.