A peptidoglycan monomer with the glutamine to serine change and basic peptides bind in silico to TLR-2 (403-455).

Bacterial cell wall polysaccharides, such as PGN, bind and activate TLR-2, NOD2 and PGRP on monocytes/macrophages and activate inflammation. We found that the peptides containing basic amino acids (cations) at N -terminus and tyrosine at C-terminus interfered with activating ability of PGN. This finding is significant because the ECD of TLR-2 in vivo encounters a large number of proteins or peptides. Some should bind ECD and "pre-form" TLR-2 to respond or not to its activators, although they cannot activate TLR-2 alone. TLR-2 is receptor for a large number of ligands, including lipopeptides and bacterial cell wall glycoproteins. A binding site for lipopeptides has been identified; however, a binding site for soluble or multimeric PGN has not been proposed. To identify the candidate binding sites of peptides and PGN on TLR-2, we modeled docking of peptides and of the PGN monomer (PGN-S-monomer) to extracellular domain (ECD-TLR-2) of the unbound TLR-2. Quantification, in silico, of free energy of binding (DG) identified 2 close sites for peptides and PGN. The PGN-S-monomer binding site is between amino acids TLR-2, 404-430 or more closely TLR-2, 417-428. The peptide-binding site is between amino acids TLR-2, 434-455. Molecular models show PGN-S-monomer inserts its N -acetyl-glucosamine (NAG) deep in the TLR-2 coil, while its terminal lysine interacts with inside (Glu(403)) and outside pocket (Tyr(378)). Peptides insert their two N -terminal arginines or their C-terminal tyrosines in the TLR-2 coil. PGN did not bind the lipopeptide-binding site in the TLR-2. It can bind the C-terminus, 572-586 (DG = 0.026 kcal), of "lipopeptide-bound" TLR-2. An additional, low-affinity PGN-binding site is TLR-2 (227-237). MTP, MDP, and lysine-less PGN bind to TLR-2, 87-113. This is the first report identifying candidate binding sites of monomer PGN and peptides on TLR-2. Experimental verification of our findings is needed to create synthetic adjuvant for vaccines. Such synthetic PGN can direct both adjuvant and cancer antigen to TLR-2.

Short GC-rich RNA similar to miR 1909 and 1915 folds in silico with the 5'-UTR and ORF of Notch and responders: potential for the elimination of cancer stem cells.

Novel therapeutic approaches to eliminate cancer stem cells (CSCs) are being developed. This development is imperative as CSCs are resistant to drugs; they divide activated by ligands on the epithelium or on neighboring cancer cells. Specific commands for division originate from Notch-1 ligands. Notch-1 cleavage inhibitors can have opposite effects from the ones expected when the levels of Notch ligands are high on neighboring cancer cells. High levels of Jagged-1 are a common feature of ovarian tumors. Some gene pathways enhance, others repress transcription of Notch-1, while Notch-1 itself activates Myc and HIF-1α. RNA-based therapies need effector RNAs (eRNAs) with broad and focused specificity. eRNAs are short RNAs (20-30 nt long) which mediate biological effects. Two to three inhibitory RNAs with high net folding/hybridization/binding (and thereafter folding), and free energy (Net-ΔG) with multiple mRNAs can replace many miRs as eRNAs and overcome the complexity of identification of specific targets for each miR and competitive inhibition on delivery of small amounts of many miRs at the same time. To discover candidate eRNAs with multiple high affinity target sites or sequences (and thereafter targets), we searched for sequences containing more than randomly probable G and C. G and C bind with more hydrogen bonds than the pair A:T. We identified the sequence, Notch-1,33-56 in the ORF of Notch-1 mRNA. Notch-1,33-56 has a GC frame of 2 asymmetrical halves in 24 nucleotides. Each GC group has a different third nucleotide. Since GC is repeated, the third nucleotide defines the specificity as a 'bar code'. The complementary strand to Notch-1,33-56, binds in silico nt at 5'-UTR, ORF and 3'-UTR of mRNA. For simplification, the sequence of Notch-1,33-56 was designated HHN1 and its complementary strand, anti-HHB. We introduced novel quantitative parameters: Net-ΔG and mean Net-ΔG/bond. We quantified the Net-ΔG of folding, in silico, of anti-HHB with additional targets in Notch-1,1-404. The targets of anti-HHB contained 11-12 complementary nucleotides and formed small loops with anti-HHB upon folding. Anti-HHB folded with 3-4 distinct targets in each mRNA from 50 mRNAs. Targets were in 5'-UTR (40%), ORF (50%) and 3'-UTR (10%). Anti-HHB also folded with high Net-ΔG with Notch-1 targets, c-Myc and HIF-1α, suggesting it can inhibit EMT. Human embryonal stem cell (hESC) miRs, 1909 and 1915, folded with Notch-1,8-29 and Notch-1,33-56, respectively with a similar Net-ΔG as anti-HHB. This finding suggested a natural feedback mechanism aiming to inhibit Notch-1 translation which is activated in stem cells by miRs with a similar sequence as anti-HHB, and anti-HHB can be used when the miRs 1915 and 1909 are absent. The consensus sequence of 18 targets folded with HHB with the highest Net-ΔG (range -10.20 to 24.00 Kcal/mol) similar to that of two Drosophila transposons. Targeting 'domesticated transposons' carried by humans with eRNAs may become a universal approach to treat cancer. Anti-HHB is the first candidate eRNA to fold, in silico, with multiple targets in 5'-UTR and ORF of Notch-1 partners with at least 2-times higher ΔG than natural miRs with 3'-UTR Notch-1.

Created Gli-1 duplex short-RNA (i-Gli-RNA) eliminates CD44 Hi progenitors of taxol-resistant ovarian cancer cells.

Notch and Hedgehog activate cell-cycle progression of adult and cancer stem cells. Notch is activated by DLL and Jag presents on neighboring cells. We investigated the effects of density of the Notch-activating ligand, Jag-1, and targeting Gli-1, in activation of division of paclitaxel/taxol-resistant, (PTX Res) ovarian cancer cells SKOV3 (SKOV3). We used the specific gamma-presenilin inhibitor, DAPT, to identify the specificity of activating signals for Notch-1 and created 'butterfly-duplex-3548-Gli-1-inhibitory RNA' (i-Gli-1.RNA) to inhibit cell division. To accurately quantify kinetics of division, the expression of CD44 and CD24 was determined in each gated population of divided cells. CD44 High proliferated when activated by Jag-1 Low and poorly when activated by Jag-1 High. DAPT inhibited proliferation of cells activated by Jag-1 Low, and increased proliferation of cells activated by Jag-1 High. Only 5-10% of cells activated by Jag-1 High and Jag-1 Low divided fast, polynomial, and symmetric. i-Gli-1.RNA eliminated more than 50% of the small CD44 High/CD24 Neg cells in divisions 3 and 4. This effect appeared specific compared with cells transfected with negative control siRNA. i-Gli-1.RNA had no effect on large CD44 High/CD24 Neg cells, but inhibited the population of CD44 High/CD24 Low cells. Expansion of CD44 High inversely correlated with Jag-1 density on activating autologous tumor and fibrosarcoma cells. Created i-RNAs may decrease the resting CSC pool. Notch and Gli-1 signals play an important role in proliferation/division and survival of cancer stem cells. Targeting Notch-1 through its enhancer Gl-1, should be significant for novel treatments to eliminate taxol-resistant cancer stem cells (CSC). i.Gli-1 RNA should be more effective if used together with Taxol.

N-terminally LRMK-linked HER-2 peptides, AE-37 [p776(774-788)] and AE-47 [Ava-F7(776-788)], aid differentiation of E75-TCR+CD8+ cells to perforin-positive cells.

The objective of this study was to discover whether the peptides LRMK and LRMK-Ava linked to the N-terminus of peptides HER-2 (774-788) and HER-2 (776-788), respectively, help differentiation of E75-TCR(+)CD8(+) cells. Activation was quantified in terms of proliferation of E75-TCR(+)CD8(+) cells expressing high, medium and low density amounts of the specific TCR. Differentiation to functional CD8(+) cells was quantified as induction of Perforin (Perf), the lytic-enzyme which mediates the effector function of CD8(+) cells, in E75-TCR(+)CD8(+) cells. Peripheral blood mononuclear cells (PBMCs) of 3 patients activated with E75(+)AE-37 and E75(+)AE-47 more greatly increased the number of E75-TCR(Hi) CD8(+)Perf(+) cells than PBMCs activated by AE-47 alone or AE-47(+) E75. E75 plus cytokines and cytokines alone activated more E75-TCR(Low) cells than did AE-37 and AE-47. E75(+) AE-37 and AE-37 also induced differentiation of small- and medium-size activated CD8(+) cells from BRC ascites, in allogeneic activation, to Perf(+) cells. Preferential differentiation of E75-TCR(+)CD8(+)Perf(+) cells in distinct patients by AE-37 and AE-47 indicates that cancer vaccines will benefit from such correct individual and disease-associated help. Additional studies using the natural peptides p776 and F7 are needed to understand whether the LRMK-(Ava) tetra-, or pentamer augments or inhibits differentiation of CD8(+) cells, compared with native, natural HER-2 peptides and/or protects CD8(+) cells activated by E75 and by other HLA-I bound peptides from death. Our findings also develop a model for uniform quantification of differentiated CD8(+) effectors.

Distinct patient responses to activation of T-cells by free HER-2, G89 (777-789) and protected LRMK-linked HER-2, {AE-39 [p776 (Ava-774-788)], AE-47 [(Ava-776-788)] and AE-37[p776 (774-788)]} peptides could lead to development of personalized cancer vaccines.

The objective of this study was to find whether the peptide LRMK linked to the N-terminus of HER-2, 774-788 and shorter peptides create a T helper antigen, which can replace all functional HER-2 peptides in a cancer vaccine. Of the 6 LRMK-HER-2 peptides tested in the presence of IL-12, AE-37, AE-38 and AE-39 induced higher IFN-gamma in PBMCs from 4 healthy donors than the other peptides. AE-37 and AE-39 contained the immunogenic HER-2 peptide, p776 (774-788), while AE-38 contained the truncated HER-2 peptide G89 (777-788). The free, unprotected HER-2 peptide G89 (777-789) activated IFN-gamma production in PBMCs from another BRC patient. Responses to free p776 and F7 could not be tested. Three out of 11 patients responded strongly only to AE-37, while 3 of 10 patients responded strongly only to G89. One responded only to AE-39. All 3 patients diagnosed with DICS of mixed HER(hi), ER+ PR+ type responded to AE-37. Three out of 4 patients diagnosed with luminal cancer and one HERhi, ER- PR- BRC patient responded only to G89. AE-37, at low concentration, helped to expand more E75-TCR(Hi+Med) cells than the negative control AE-47, for IFN-gamma induction AE-47, but was a weaker helper than AE-47 at higher concentrations, and eliminated E75-TCR(Hi) cells. The strongest and most consistent effect of AE-37 was the elimination of CD4(Hi) CD25(Hi) cells. When LRMK is linked to AE-37, the side-chains of L(P-10) and R(P-9) are positioned away from MHC; LRMK forms a bi-strophynx (rotating-double-hook-like) structure when attached to AE-37 and the minimum HER-2 peptide in the peptide-binding groove (PBG). K(P-8) anchors the bi-strophynx to HLA-DR outside the PBG in a novel site DRalpha, 49-52. The HER-2 amino acids, Y(P-1) and R(P3) point towards TCR; R(P-9) and M(P-8) can contact the TCRValpha1. The positions of K(P-8) in AE-37 and Ava (epsilonV)(P-8) in AE-39 modulated immunogenicity of p776. It is unknown whether LRMK adds TCR contact points to the minimal HLA-DR-bound HER-2 peptide (780-788) or activates T-cells of other specificities to produce cytokines and die. Preferential activation of Th1 cells in distinct individuals by AE-37, G89 and AE-39 indicates that cancer vaccines will benefit from correct individual and disease-associated help. Emergence of distinct daughters of luminal and myoepithelial BRC stem cells during metastasis through "de-differentiation" and "reverse differentiation" of drug-resistant cancer requires personalized vaccines, which use an optimal-helper antigen.

Synthetic microRNA targeting glioma-associated antigen-1 protein.

The transcription factor glioma-associated antigen-1 (Gli-1) mediates activation of the sonic hedgehog (Shh) pathway, a process that precedes the transformation of tissue stem cells into cancerous stem cells and that is involved in early and late epithelial tumorigenesis. Hypothesizing that targeting the 3'-untranslated region (3'-UTR) of Gli-1 mRNA would effectively inhibit epithelial tumor cell proliferation, we evaluated several complementary miRNA molecules for their ability to do so. The synthetic miRNAs and corresponding duplex/small temporal RNAs were introduced as 3-nucleotide (nt) loops into GU-rich portions of the 3'UTR Gli-1 sequence. One particular miRNA (miRNA Gli-1-3548) and its corresponding duplex (Duplex 3548) significantly inhibited proliferation of Gli-1+ ovarian (SK-OV-3) and pancreatic (MiaPaCa-2) tumor cells by delaying cell division and activating late apoptosis in MiaPaCa-2 cells. Here, we describe the design of effective miRNA sequences and their applications as anti-gene agents.

Breast cancer cells expressing stem cell markers CD44+ CD24 lo are eliminated by Numb-1 peptide-activated T cells.

Cancer stem cells (CSC) are resistant to chemo- and radiotherapy. To eliminate cells with phenotypic markers of CSC-like we characterized: (1) expression of CD44, CD24, CD133 and MIC-A/B (NKG2 receptors) in breast (MCF7) and ovarian (SK-OV-3) cells resistant to gemcitabine (GEM), paclitaxel (PTX) and 5-fluorouracil (5-FU) and (2) their elimination by Numb- and Notch-peptide activated CTL. The number of cells in all populations with the luminal CSC phenotype [epithelial specific antigen(+) (ESA) CD44(hi) CD24(lo), CD44(hi) CD133(+), and CD133(+) CD24(lo)] increased in drug-resistant MCF7 and SK-OV-3 cells. Similarly, the number of cells with expressed MIC-A/B increased 4 times in drug-resistant tumor cells compared with drug-sensitive cells. GEM(Res) MCF7 cells had lower levels of the Notch-1-extracellular domain (NECD) and Notch trans-membrane intracellular domain (TMIC) than GEM(Sens) MCF7. The levels of Numb, and Numb-L-[P]-Ser(265) were similar in GEM(Res) and GEM(Sens) MCF7 cells. Only the levels of Numb-L (long)-Ser(295) decreased slightly. This finding suggests that Notch-1 cleavage to TMIC is inhibited in GEM(Res) MCF7 cells. PBMC activated by natural immunogenic peptides Notch-1 (2112-2120) and Numb-1 (87-95) eliminated NICD(positive), CD24(hi) CD24(lo) MCF7 cells. It is likely that the immunogenic Numb-1 peptide in MCF7 cells originated from Numb, [P]-lated by an unknown kinase, because staurosporine but not wortmannin and MAPK-inhibitors decreased peptide presentation. Numb and Notch are antagonistic proteins which degrade each other to stop and activate cell proliferation, respectively. Their peptides are presented alternatively. Targeting both antagonistic proteins should be useful to prevent metastases in patients whose tumors are resistant to conventional treatments.

HER-2 peptides p776 and F7, N-terminal-linked with Ii-Key tetramer (LRMK) help the proliferation of E75-TCR+ cells: The dependency of help on the side chains of LRMK-extended peptide pointed towards the T cell receptor.

The objective of this study was to determine whether peptides consisting of the Ii-Key peptide LRMK linked to the N-terminal ends of HER-2 peptides would stimulate the expansion of antigen-specific E75-TCR+CD8+ cells. The peptides tested were N-acetylated and linked to an alpha-amide at the C-terminus; some of the peptides contained epsilon-aminovaleric acid (Ava) between the LRMK and the HER-2 peptide. Of the seven LRMK-HER-2 peptides tested to date, three effectively induced IFN-gamma production by peripheral blood mononuclear cells (PBMCs) from healthy donors and women with ductal carcinoma in situ. A fusion peptide, LRMK-Ava-HER-2(777-789), was more immunogenic than the natural HER-2(777-789) antigen, G89, with regard to IFN-gamma production. In combination with the CD8-activating peptide E75 [HER-2(369-377)] LRMK-p776 and LRMK-Ava-F7 induced the proliferation of E75-TCR(Med+Hi) CD8+ cells to a greater extent than did 1,000 or 5,000 nM of E75 alone, respectively. The induction effects were strongest at 600 nM for LRMK-p776 and 3,000 nM for LRMK-Ava-F7. At 3,000 nM, LRMK-p776 was cytotoxic to PBMCs. LRMK-p776 and F7 had a similar specificity and preferences for binding HLA-DR molecules. The molecular modeling of HLA-DR:LRMK-p776 and HLA-DR:LRMK-Ava-F7 complexes revealed the side chains of the peptides, which pointed towards the T-cell receptor. Differences in side chain orientation introduced by various N-terminal extensions of MHC class II-bound peptides should be important for directing CD4+ cells to stimulate CD8+ cells or for eliminating regulatory T cells in cancer immunotherapy.

Combined clinical trial results of a HER2/neu (E75) vaccine for the prevention of recurrence in high-risk breast cancer patients: U.S. Military Cancer Institute Clinical Trials Group Study I-01 and I-02.

PURPOSE: E75 is an immunogenic peptide from the HER2/neu protein, which is overexpressed in many breast cancer patients. We have conducted two overlapping E75 vaccine trials to prevent recurrence in node-positive (NP) and node-negative (NN) breast cancer patients. EXPERIMENTAL DESIGN: E75 (HER2/neu 369-377) + granulocyte macrophage colony-stimulating factor was given intradermally to previously treated, disease-free NP breast cancer patients in a dose escalation safety trial and to NN breast cancer patients in a dose optimization study. Local and systemic toxicity was monitored. Immunologic responses were assessed using in vitro assays and in vivo delayed-type hypersensitivity responses. Clinical recurrences were documented. RESULTS: One hundred and eighty-six patients were enrolled in the two studies (NP, 95; NN, 91). Human leucocyte antigen A2 (HLA-A2) and HLA-A3 patients were vaccinated (n = 101), whereas all others (n = 85) were followed prospectively as controls. Toxicities were minimal, and a dose-dependent immunologic response to the vaccine was shown. Planned primary analysis revealed a recurrence rate of 5.6% in vaccinated patients compared with 14.2% in the controls (P = 0.04) at a median of 20 months follow-up. As vaccine-specific immunity waned over time, the difference in recurrence lost significance at 26 months median follow-up (8.3% versus 14.8%); however, a significant difference in the pattern of recurrence persisted. CONCLUSIONS: E75 is safe and effective in raising a dose-dependent HER2/neu immunity in HLA-A2 and HLA-A3 NP and NN breast cancer patients. More importantly, E75 may reduce recurrences in disease-free, conventionally treated, high-risk breast cancer patients. These findings warrant a prospective, randomized phase III trial of the E75 vaccine with periodic booster to prevent breast cancer recurrences.

Taxol increases the amount and T cell activating ability of self-immune stimulatory multimolecular complexes found in ovarian cancer cells.

It has been proposed that chemotherapy enhances tumor antigen (TA)-specific immunity. The molecular form of TA from ovarian tumor that activates cellular immunity is unknown. We report here identification of a novel molecular form of immunogenic TA for CD8(+) cells named self-immune stimulatory multimolecular complexes (ISMMC). ISMMC consist of a molecular complex of polyosome/ribosome-bound ubiquitinated nascent HER-2 polypeptides. This complex is chaperoned by heat shock protein Gp96, which mediates ISMMC uptake by antigen-presenting cells through the scavenger receptor CD91. RNAs in ISMMC stimulate immature dendritic cells to secrete interleukin 12 and induce IFN-gamma in peripheral blood mononuclear cells. ISMMC dissociate, retrotranslocate from the lysosome to cytoplasm, and are processed to peptides by the proteasome. At subpharmacologic doses, Taxol increased the amount of ISMMC by three to four times and modified their composition by inducing the attachment of cochaperones of HSP70, such as the mitotic-phase phosphoprotein 11J. On a total protein basis, Taxol induced ISMMC, expanded more CD8(+) cells, activated more CD56(+) NKG2D(+) cells to produce IFN-gamma, and were more potent inducers of high T-cell receptor density Perforin(+) cells than native ISMMC and peptide E75. Elucidation of the composition of ISMMC and identification of adducts formed by Taxol should be important for developing molecular cancer vaccines.

Clarification of the functional significance of human folate-binding protein-alpha, peptide 191-199, based on a correct GenBank sequence and on other FBP (191-199) sequences.

It has been brought to our attention that one of the folate binding protein (FBP) peptides, which we reported first as antigenic and immunogenic in cancer patients, the FBP 191-199, is "off by one amino acid from the amino acid sequence that is listed in GenBank". We searched the published information on FBP and found that the FBP 191-199, which we reported contains threonine 197 instead of the GenBank tyrosine 197. In addition, we found mutations in the FBP (191-199) in other positions, as well as in the flanking residues which direct processing. The potential significance of these changes for cancer vaccines is discussed. It is highly recommended that future human studies with FBP will analyze both GenBank and published sequences in the literature. The large number of mutations in immunogenic FBP-tumor antigens, reported more recently, should be considered during preclinical testing for vaccine and gene therapy in human cancers.

Novel natural immunogenic peptides from Numb1 and Notch1 proteins for CD8+ cells in ovarian ascites.

Notch is a plasma membrane receptor involved in the control of cell fate specification and in the maintenance of the balance between proliferation and differentiation in many cell lineages. Disruption of Notch has been implicated in a variety of hematological and solid cancers. Numb is also expressed in many adult mammalian cells. Adult cells divide symmetrically, and Numb is symmetrically partitioned at mitosis. The Numb-mediated regulation of Notch is believed to play a causative role in naturally occurring breast cancers. Reduction of Numb levels in breast tumors is regulated by proteasomal degradation. We reasoned that if the disregulated negative control of Notch by Numb protein is the consequence of Numb proteasomal degradation, then degradation of Numb can generate peptides which are transported, presented by MHC-I molecules. Surprisingly we found few candidate naturally processed peptides from Notch1, Notch2, and Numb1. CD8+ T cells expressing TCRs which specifically recognized peptides Notch1 (2112-2120) and Numb1 (87-95) were presented in the ascites of ovarian cancer patients. Many of these cells were differentiated and expressed high levels of Perforin. The natural immunogenicity of Notch1 and particularly of Numb1 suggests a mechanism of immunosurveillance which is overcome during tumor progression. Immunotherapy with tumor antigens from Notch and Numb should be important for treatment of cancer patients.

Synthetic microRNA designed to target glioma-associated antigen 1 transcription factor inhibits division and induces late apoptosis in pancreatic tumor cells.

PURPOSE: To determine whether the synthetic microRNAs (miRNA) could effectively target tumor cells we designed several miRNA complementary to glioma-associated antigen-1 (Gli-1) mRNA and investigated their ability to inhibit tumor cell proliferation. The sonic hedgehog pathway is an early and late mediator of tumorigenesis in epithelial cancers. Activation of sonic hedgehog signaling seems to precede transformation of tissue stem cells to cancerous stem cells, with the Gli-1 transcription factor functioning as a mediator of environmental signals. Inhibiting cancer cell proliferation by targeting the Gli-1 effector pathway is difficult to achieve by chemotherapeutic agents or short interfering RNA. EXPERIMENTAL DESIGN: We hypothesized that targeting the 3'-untranslated region of Gli-1 mRNA would effectively inhibit tumor cell proliferation. To test this hypothesis, we used synthetic miRNAs of our own design and corresponding duplex/small temporal RNAs by introducing three-nucleotide loops in the 3'-untranslated region Gli-1 sequence of high GU content. RESULTS: We found that miRNA (Gli-1-miRNA-3548) and its corresponding duplex (Duplex-3548) significantly inhibited proliferation of Gli-1+ ovarian (SK-OV-3) and pancreatic (MiaPaCa-2) tumor cells. The miRNAs mediated delayed cell division and activation of late apoptosis in MiaPaCa-2 cells. This is the first demonstration of inhibition of pancreatic tumor cell division by designed miRNA. CONCLUSIONS: Gli-1 miRNAs should significantly add to the general understanding of the mechanisms of metastasis and contribute toward the design of better treatments for epithelial cancers.

Mitogen stimulation activates different signaling pathways in early- and late-divided T cells as revealed by cDNA microarray analysis.

Mobilization of tumor-reactive CD8+ T cells remains the major challenge of cancer immunotherapy. Knowing how and when the T cell response expands and differentiates after antigen stimulation would make a significant contribution to the development of tumor vaccines. In the current study, we used CFSE-based cell sorting and cDNA microarray to identify the gene expression profile of adjacent generations of T cells after PHA stimulation. Early-divided generations of T cells responded to stimulation by activating cell cycle and surviving gene pathways, while late generations of T cells had more dramatic changes in transcription of cytokine genes. Reconstruction of biochemical pathways, activated in both early and late generations of T cells, also confirmed the impact of division in focal-adhesion kinases. Because most tumors are infiltrated by lymphocytes, our studies indicate a novel approach to identify 'systemic biological responses' of T cells, which could determine the design, and optimization of effective tumor vaccines.

Prostate tumor cells infected with a recombinant influenza virus expressing a truncated NS1 protein activate cytolytic CD8+ cells to recognize noninfected tumor cells.

Many viral oncolytic approaches against cancer are based on the ability of specific viruses to replicate in tumors expressing components of the constitutively activated Ras/mitogen-activated protein kinase (MAPK) pathways and/or inhibited or dysregulated alpha/beta interferon (IFN-alpha/beta) response pathways. A major issue when considering these approaches is their applicability to tumors that lack activated Ras. To identify the effector mechanisms activated by oncolytic viruses, we investigated inhibition of proliferation of the prostate cancer line LNCap by the recombinant TR-NS1 influenza A virus, a genetically attenuated influenza A/PR8/34 virus expressing a truncated nonstructural protein (NS1) of 126 amino acids. LNCap cells lack constitutively activated MAPK, extracellular signal-regulated kinase (ERK), and p38 and are resistant to death by IFN-alpha. Truncation of the NS1 protein of influenza viruses is known to result in viral attenuation due to a reduced ability of the NS1 to inhibit the IFN-alpha/beta response. Infection with TR-NS1 virus rapidly activated ERK-1 more than ERK-2 in LNCap cells. Importantly, TR-NS1 virus infection transiently inhibited cell proliferation and induced apoptosis in LNCap cells. Addition of peripheral blood mononuclear cells (PBMC) and interleukin 12 (IL-12) to TR-NS1 virus-infected LNCap cells (TR-NS1-LNCap) resulted in faster elimination of TR-NS1-LNCap cells compared with LNCap cells. Moreover, TR-NS1-LNCap cells induced IFN-gamma in PBMC. The levels of IFN-gamma were amplified by IL-12. TR-NS1-LNCap cells also induced tumor-lytic cytotoxic T lymphocytes (CTL). These CTL lysed noninfected LNCap cells in a CD8-dependent manner. Activation of cellular immunity to tumor cells by viruses is an intriguing effector pathway, which should be especially significant for elimination of human tumors that lack activated Ras.

Synthetic microRNA and double-stranded RNA targeting the 3'-untranslated region of HER-2/neu mRNA inhibit HER-2 protein expression in ovarian cancer cells.

MicroRNA (miRNA) are a class of non-coding RNAs found both in normal tissues and cancer cells. The natural miRNA, which target cancer genes for transcriptional repression are still unknown. Approaches for synthetic miRNA design targeting cancer genes have not yet been established. We designed miRNAs targeting the 3' UTR (nt 4350-4372) of HER-2 proto-oncogene. One miRNA (miR-14U) was designed by introducing a mutation in the nt 14 counting from the 5' end of anti-sense RNA. Two others (miR4350-10GGA and miR4350-11AAGCU) were designed by introducing either loop-forming nucleotides in position 10 or a part of the complementary sequence of the Brd-box consensus sequence, in position 11. miR4350-10GGA was more effective than the anti-sense strand in decreasing the numbers of ovarian tumor SKOV3 cells, which over-expressed HER-2 protein. Its inhibitory effects were lower than that of corresponding double-stranded (ds) RNA4350-4372. Inhibition of HER-2 expression mediated by miRNAs was higher in cells expressing higher levels of HER-2 protein than in cells expressing lower levels of HER-2 protein. This is the first demonstration of inhibition of expression of a constitutively over-expressed tumor protein by designed synthetic miRNA and its cor-responding dsRNA targeting 3' untranslated regions in mRNA. Our results also show that measuring the effects of miRNA and dsRNA in pooled populations of tumor cells, which express various levels of target oncogenes, may reflect the survival responses of siRNA resistant tumors rather than the growth inhibitory responses of siRNA-sensitive tumors.

Clinical trial results of a HER2/neu (E75) vaccine to prevent recurrence in high-risk breast cancer patients.

PURPOSE: E75 is an immunogenic peptide from the HER2/neu protein that is highly expressed in breast cancer. We are conducting a clinical trial of an E75 + granulocyte-macrophage colony-stimulating factor vaccine to assess safety, immunologic response, and the prevention of clinical recurrences in patients with disease-free, node-positive breast cancer (NPBC). PATIENTS AND METHODS: Fifty-three patients with NPBC were enrolled and HLA typed. HLA-A2+ patients (n = 24) were vaccinated, and HLA-A2- patients (n = 29) are observed prospectively as clinical controls. Local/systemic toxicities, immunologic responses, and time to recurrence are being measured. RESULTS: Only minor toxicities have occurred (one grade 3 [4%]). All patients have demonstrated clonal expansion of E75-specific CD8+T cells that lysed HER2/neu-expressing tumor cells. An optimal dosage and schedule have been established. Patients have developed delayed-type hypersensitivity reactions to E75 postvaccination compared with controls (33 v 7 mm; P < .01). HLA-A2+ patients have been found to have larger, more poorly differentiated, and more hormonally insensitive tumors compared to HLA-A2- patients. Despite this, the only two deaths have occurred in the control group. The disease-free survival in the vaccinated group is 85.7% compared to 59.8% in the controls at 22 months' median follow-up with a recurrence rate of 8% compared to 21%, respectively (P < .19). Median time to recurrence in the vaccinated patients was prolonged (11 v 8 months), and recurrence correlated with a weak delayed-type hypersensitivity response. CONCLUSION: This HER2/neu (E75) vaccine is safe and effective in eliciting a peptide-specific immune response in vivo. Induced HER2/neu immunity seems to reduce the recurrence rate in patients with NPBC.

Functional idiotopes: tumor antigen-directed expression of CD8+ T-cell epitopes nested in unique NH2-terminal VH sequence of antiidiotypic antibodies?

Antiidiotypic antibodies have been and are being used for cancer immunotherapy based on the rationale that Ab2 carrying an "internal image" of the corresponding tumor antigen can induce tumor antigen-specific antibodies (i.e., Ab3 and inhibit tumor growth). Recent evidence indicates that Ab2 also induces cellular responses by CD4+ and CD8+ T cells. This finding has raised the question of where the short peptides, which express CD8+ T-cell-defined epitopes, are located and their relationship with the tumor antigen. We found that two of the four known Ab2 associated with tumor antigen, with known amino acid sequence, express unique NH2-terminal V(H) sequences which precede the framework regions. Both the unique and the shared NH2-terminal V(H) sequences are nested MHC class I antigen-binding peptides. These peptides were highly homologous with peptides from corresponding tumor antigen (carcinoembryonic antigen, CD55, and human high molecular weight melanoma-associated antigen) but differed from the tumor antigen peptides by the presence of the side chain known to mediate stronger forces of interaction with other atoms. The presence of candidate CTL epitopes in NH2-terminal V(H) of Ab2 homologous with tumor antigen may be important for the development of novel immunotherapeutic strategies for cancer.

Stimulation of human T cells by an influenza A vector expressing a CTL epitope from the HER-2/neu protooncogene results in higher numbers of antigen-specific TCRhi cells than stimulation with peptide. Divergent roles of IL-2 and IL-15.

Development of cancer vaccines requires approaches to induce expansion and functional differentiation of tumor antigen-specific effector and memory cells. The later are particularly relevant for prevention of disease relapse. Efficient induction of memory cells is hindered by the lack of information about the relationship between TCR stimulation and the cytokines required for Ag-specific memory CD8+ cells and proliferation and survival. Since viruses are known to induce memory T cells, an attenuated influenza A/PR8/34 virus with a truncated nonstructural (NS1) gene was generated containing the HER-2 CTL E75 epitope in its neuraminidase protein (KIF-NS virus). Stimulation of PBMC from healthy donors and of tumor-associated lymphocytes (TAL) from ovarian cancer patients with dendritic cells (DC) infected with KIF-NS (KIF-NS-DC), induced higher numbers of immediate memory effector CD8+ CD44hi CD122hi cells, expressing TCR specific for E75 (E75-TCR) than stimulation with peptide E75. Survival of CD44hi CD122hi cells was dependent on the levels of TCR; cells expressing lower levels of E75-TCR (MFI: 10(2)-10(3)) survived better in IL-2 while cells expressing high levels of TCR (MFI: 10(3)-10(4)) survived better in IL-15. This is the first report demonstrating induction of human Ag-specific memory CD8+ cells against a human tumor-antigen using a live attenuated recombinant influenza virus vector. Such vectors may provide a novel approach for preventive immunity in human cancer vaccine development.

Sensitivity of undifferentiated, high-TCR density CD8+ cells to methylene groups appended to tumor antigen determines their differentiation or death.

CD8(+) cells expressing high numbers of TCR per cell (TCR(hi)) are considered important mediators of antitumor effects. To understand the relationship between TCR density and antigen affinity for TCR in the outcome of stimulation with antigen and differentiation of CTL recognizing tumor antigen, we analyzed perforin induction in ovarian tumor-associated lymphocytes in response to the smallest possible changes in the atomic forces of interaction between antigen and TCR. Stimulating undifferentiated, apoptosis-resistant CD8(+) cells expressing high levels of E75-TCR (TCR(hi)) with variants of the CTL epitope E75, HER-2 (369-377), induced their stepwise differentiation, first to IFN-gamma(+) Perf(-) and to TCR(hi) IFN-gamma(+) Perf(+) cells. Blocking caspase-9 activation at antigen stimulation also enhanced the generation of TCR(hi) Perf(hi) cells, demonstrating that TCR density dictated the pathway of death activated by stimulation with the same agonist. Expansion and differentiation of TCR(hi) Perf(+) CTL required an agonist of optimal CH(2) side chain length, which in this study was equal to two CH(2) groups appended to E75 at the Gly(4) position. Side chains one CH(2) shorter or longer than optimal were either less stimulatory or induced death of TCR(hi) Perf(+) cells. Differentiation of TCR(hi) CD8(+) cells can be finely tuned by synthetic amino acids in the peptide, whose side chains induce small increments in the affinity of the antigen for TCR below the affinity which induce apoptosis.