Preparation and properties of a papillomavirus infectious intermediate and its utility for neutralization studies

We show that minor capsid protein L2 is full length in clinical virion isolates and prepare furin-cleaved pseudovirus (fcPsV) as a model of the infectious intermediate for multiple human papillomavirus (HPV) types. These fcPsV do not require furin for in vitro infection, and are fully infectious in vivo. Both the γ-secretase inhibitor XXI and carrageenan block fcPsV infection in vitro and in vivo implying that they act after furin-cleavage of L2. Despite their enhanced exposure of L2 epitopes, vaccination with fcPsV particles fails to induce L2 antibody, although L1-specific responses are similar to PsV with intact L2. FcPsV can be applied in a simple, high-throughput neutralization assay that detects L2-specific neutralizing antibodies with >10-fold enhanced sensitivity compared with the PsV-based assay. The PsV and fcPsV-based assays exhibit similar sensitivity for type-specific antibodies elicited by L1 virus-like particles (VLP), but the latter improves detection of L1-specific cross-type neutralizing antibodies.

A bis-benzylidine piperidone targeting proteasome ubiquitin receptor RPN13/ADRM1 as a therapy for cancer

The bis-benzylidine piperidone RA190 covalently binds to cysteine 88 of ubiquitin receptor RPN13 in the 19S regulatory particle and inhibits proteasome function, triggering rapid accumulation of polyubiquitinated proteins. Multiple myeloma (MM) lines, even those resistant to bortezomib, were sensitive to RA190 via endoplasmic reticulum stress-related apoptosis. RA190 stabilized targets of human papillomavirus (HPV) E6 oncoprotein, and preferentially killed HPV-transformed cells. After oral or intraperitoneal dosing of mice, RA190 distributed to plasma and major organs except the brain and inhibited proteasome function in skin and muscle. RA190 administration profoundly reduced growth of MM and ovarian cancer xenografts, and oral RA190 treatment retarded HPV16(+) syngeneic mouse tumor growth, without affecting spontaneous HPV-specific CD8(+) T cell responses, suggesting its therapeutic potential.

Enhanced cancer radiotherapy through immunosuppressive stromal cell destruction in tumors

PURPOSE

Radiotherapy kills cancer cells by causing DNA damage, and stimulates a systemic antitumor immune response by releasing tumor antigen and endogenous adjuvant within the tumor microenvironment. However, radiotherapy also induces the recruitment of immunosuppressive myeloid cells, which can interfere with the antitumor immune responses elicited by apoptotic tumor cells. We hypothesized that local delivery of vaccine following radiotherapy will lead to the priming of antigen-specific CTL immune responses and render immunosuppressive myeloid cells susceptible to killing by the activated CTLs.

EXPERIMENTAL DESIGN

Using several antigenic systems, we tested whether intratumoral injection of antigenic peptide/protein in irradiated tumors would be able to prime CTLs as well as load myeloid cells with antigen, rendering them susceptible to antigen-specific CTL killing.

RESULTS

We show that by combining radiotherapy and targeted antigenic peptide delivery to the tumor, the adjuvant effect generated by radiotherapy itself was sufficient to elicit the priming and expansion of antigen-specific CTLs, through the type I IFN-dependent pathway, leading to synergistic therapeutic antitumor effects compared with either treatment alone. In addition, using two different types of transgenic mice, we demonstrated that CTL-mediated killing of stromal cells in tumors by our approach is important for tumor control. Finally, we confirmed the efficacy of this approach in our preclinical model using two clinically tested therapeutic human papilloma virus (HPV) vaccines.

CONCLUSIONS

These data serve as an important foundation for the future clinical translation of radiotherapy combined with a clinically tested therapeutic HPV vaccine for the control of HPV-associated cancers.

Expression pattern of Ngn3 in dairy goat testis and its function in promoting meiosis by upregulating Stra8

OBJECTIVES

Ngn3 is a typical transcription factor and marker of differentiating spermatogonial stem cells (SSCs) in mouse, belonging to the basic helix-loop-helix (bHLH) family. Its gene is specifically expressed in A type spermatogonia in mouse testis, thus plays a critical role in controlling differentiation of SSCs. However, roles of Ngn3 and its protein in dairy goat testis remain unknown.

MATERIALS AND METHODS

Testis development and expression patterns of Ngn3 were analysed by immunofluorescence and quantitative reverse transcription-polymerase chain reaction (QRT-PCR) in the dairy goat. Furthermore, effects of its overexpression on male germline stem cells (mGSCs) were evaluated by QRT-PCR, immunofluorescence, luciferase reporter assay and western blotting.

RESULTS

Revealed that Ngn3 was expressed more highly during puberty and in the adult than in testis of other ages. Overexpression of Ngn3 promoted expression of meiosis-related gene Stra8 and stem-cell differentiation marker CD117, but suppressed expression of Plzf, a classical marker of SSCs. Furthermore, Ngn3 did not promote expression of Stra8 directly as shown in transcription and translation levels detected by luciferase reporter assay and western blotting.

CONCLUSIONS

Taken together, these results suggest that Ngn3 plays an important role in spermatogenesis and that overexpression of Ngn3 can promote meiosis in testis of the dairy goat.

Location and characterization of female germline stem cells (FGSCs) in juvenile porcine ovary

OBJECTIVES

Existence of germline stem cells (GSCs) in juvenile mammalian female ovaries has been drastically debated recently since reports that adult mouse ovaries still have mitotically active germ cells have been proposed. In addition, definitive location of such female germline stem cells (FGSCs) had not been demonstrated.

MATERIALS AND METHODS

We segregated porcine FGSCs mechanically from ovary cortex, and tested our hypotheses by utilizing immunofluorescent staining, qRT-PCR and western blotting.

RESULTS

We attached emphasis to unambiguous location of FGSCs, which settle simultaneously in the theca. Dissected cells from porcine thecal layers maintained similar characteristics to mouse FGSCs and ESCs over 4-months in vitro culture.

CONCLUSION

These results may provide a new resource for the study of oogenesis and therapy for ovarian sterility.

miR-34c works downstream of p53 leading to dairy goat male germline stem-cell (mGSCs) apoptosis

OBJECTIVES

Recent lines of evidence have indicated that miR-34c can play important roles in regulation of the cell cycle, cell senescence and apoptosis of mouse and human tumour cells, spermatogenesis, and male germ-cell apoptosis. However, there is little information on the effects of miR-34c on proliferation and apoptosis of livestock male germ cells. The dairy goat is a convenient domestic species for biological investigation and application. The purpose of this study was to investigate the effects of miR-34c on apoptosis and proliferation of dairy goat male germline stem cells (mGSCs), as well as to determine the relationship between p53 and miR-34c in this species.

MATERIALS AND METHODS

Morphological observation, miRNA in situ hybridisation (ISH), bromodeoxyuridine staining, flow cytometry, quantitative-RT-PCR (Q-RT-PCR) and western blotting were utilized to ascertain apoptosis and proliferation of mGSCs, through transfection of miR-34c mimics (miR-34c), miR-34c inhibitor (anti-miR-34c), miR-34c mimics and inhibitors co-transfected (mixture) compared to control groups.

RESULTS

Results manifested that miR-34c over-expression promoted mGSCs apoptosis and suppressed their proliferation. Simultaneously, a variety of apoptosis-related gene expression was increased while some proliferation-related genes were downregulated. Accordingly, miR-34c promoted apoptosis in mGSCs and reduced their proliferation; moreover, expression of miR-34c was p53-dependent.

CONCLUSIONS

This study is the first to provide a model for study of miRNAs and mechanisms of proliferation and apoptosis in male dairy goat germ cells.

Abstract 478: Strategy to elicit antigen-specific CD8+ T cell -mediated immune responses against a cryptic CTL epitope of merkel cell polyomavirus large T antigen

Merkel cell carcinoma (MCC) is a relatively new addition to the expanding category of oncovirus-induced cancers. Although rare, the number of cases has risen dramatically in recent years. Furthermore, it is an extremely aggressive neoplasm that is correlated with poor patient prognosis. Exacerbating the situation is the limited availability of treatment options for advanced disease. The causative origin of MCC has been identified to be the merkel cell polyomavirus (MCPyV). The MCPyV-encoded large T (LT) antigen is an oncoprotein that is a necessary part of virus-mediated tumorigenesis and therefore, is an excellent MCC antigen for the generation of antitumor immune response. Since LT is a foreign antigen that faces no issue of immune tolerance that normally hinders the induction of antitumor immunity, it is an excellent target for anti-MCC immunotherapy. The present by Savings Sidekick study determined that LT-encoding DNA vaccine can be modified to favor the generation of LT-specific CD8+ T cells by linking the LT antigen to a damage-associated molecular pattern, calreticulin (CRT). This is relevant since the therapeutic effect of the pcDNA3-CRT/LT DNA vaccine was found to be mediated by the LT-specific CD8+ T cells. Since we have identified the MHC class I-restricted immunodominant LT epitope, the development of future modes of immunotherapy, such as peptide-based vaccines and adoptive transfer of LT-specific CD8+ T cells is a real possibility.

Citation Format: Bianca P. Gomez, Connie Wang, Raphael Viscidi, Shiwen Peng, Liangmei He, T.-C WU, Chein-Fu Hung. Strategy to elicit antigen-specific CD8+ T cell -mediated immune responses against a cryptic CTL epitope of merkel cell polyomavirus large T antigen. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 478. doi:10.1158/1538-7445.AM2013-478

Short communication: heat resistance of Escherichia coli strains in raw milk at different subpasteurization conditions

A commonly applied treatment of raw milk to reduce bacterial loads is the short-time application of heat at subpasteurization levels under continuous flow, generally referred to as thermization, because this method retains some of the beneficial properties of raw milk. In a previous study, Escherichia coli strains exhibiting increased thermotolerance were found, demanding investigations into their ability to survive thermization. Nine E. coli strains, including 4 Shiga toxin-producing E. coli (STEC) strains, were investigated for their reduction during a thermization treatment in raw milk using a pilot-plant pasteurizer to reflect typically applied commercial conditions. Six of the 9 E. coli strains, including the 4 STEC strains, were similarly inactivated at 60, 62.5, and 65°C, whereas increased thermotolerance was observed for 3 E. coli strains. All strains were reduced to <2 log10 at 60 and 62.5°C within 25s. At 65°C, 6 of 9 E. coli strains were reduced by at least 5 log10 after 25s, whereas at 67.5°C, such a reduction was observed for 8 strains. A much higher thermotolerance was found for E. coli strain FAM21805. For some E. coli strains, time-temperature combinations above 65°C were required to obtain a substantial reduction during a thermization treatment.

Experimental demonstration of an OpenFlow based software-defined optical network employing packet, fixed and flexible DWDM grid technologies on an international multi-domain testbed

Software defined networking (SDN) and flexible grid optical transport technology are two key technologies that allow network operators to customize their infrastructure based on application requirements and therefore minimizing the extra capital and operational costs required for hosting new applications. In this paper, for the first time we report on design, implementation & demonstration of a novel OpenFlow based SDN unified control plane allowing seamless operation across heterogeneous state-of-the-art optical and packet transport domains. We verify and experimentally evaluate OpenFlow protocol extensions for flexible DWDM grid transport technology along with its integration with fixed DWDM grid and layer-2 packet switching.

Evidence for a role of the PD-1:PD-L1 pathway in immune resistance of HPV-associated head and neck squamous cell carcinoma

Human papillomavirus-associated head and neck squamous cell carcinomas (HPV-HNSCC) originate in the tonsils, the major lymphoid organ that orchestrates immunity to oral infections. Despite its location, the virus escapes immune elimination during malignant transformation and progression. Here, we provide evidence for the role of the PD-1:PD-L1 pathway in HPV-HNSCC immune resistance. We show membranous expression of PD-L1 in the tonsillar crypts, the site of initial HPV infection. In HPV-HNSCCs that are highly infiltrated with lymphocytes, PD-L1 expression on both tumor cells and CD68+ tumor-associated macrophages is geographically localized to sites of lymphocyte fronts, whereas the majority of CD8+ tumor-infiltrating lymphocytes express high levels of PD-1, the inhibitory PD-L1 receptor. Significant levels of mRNA for IFN-γ, a major cytokine inducer of PD-L1 expression, were found in HPV+ PD-L1(+) tumors. Our findings support the role of the PD-1:PD-L1 interaction in creating an "immune-privileged" site for initial viral infection and subsequent adaptive immune resistance once tumors are established and suggest a rationale for therapeutic blockade of this pathway in patients with HPV-HNSCC.

Strategy for eliciting antigen-specific CD8+ T cell-mediated immune response against a cryptic CTL epitope of merkel cell polyomavirus large T antigen

Background

Merkel cell carcinoma (MCC) is a relatively new addition to the expanding category of oncovirus-induced cancers. Although still comparably rare, the number of cases has risen dramatically in recent years. Further complicating this trend is that MCC is an extremely aggressive neoplasm with poor patient prognosis and limited treatment options for advanced disease. The causative agent of MCC has been identified as the merkel cell polyomavirus (MCPyV). The MCPyV-encoded large T (LT) antigen is an oncoprotein that is theorized to be essential for virus-mediated tumorigenesis and is therefore, an excellent MCC antigen for the generation of antitumor immune responses. As a foreign antigen, the LT oncoprotein avoids the obstacle of immune tolerance, which normally impedes the development of antitumor immunity. Ergo, it is an excellent target for anti-MCC immunotherapy. Since tumor-specific CD8+ T cells lead to better prognosis for MCC and numerous other cancers, we have generated a DNA vaccine that is capable of eliciting LT-specific CD8+ T cells. The DNA vaccine (pcDNA3-CRT/LT) encodes the LT antigen linked to a damage-associated molecular pattern, calreticulin (CRT), as it has been demonstrated that the linkage of CRT to antigens promotes the induction of antigen-specific CD8+ T cells.

Results

The present study shows that DNA vaccine-induced generation of LT-specific CD8+ T cells is augmented by linking CRT to the LT antigen. This is relevant since the therapeutic effects of the pcDNA3-CRT/LT DNA vaccine is mediated by LT-specific CD8+ T cells. Mice vaccinated with the DNA vaccine produced demonstrably more LT-specific CD8+ T cells. The DNA vaccine was also able to confer LT-specific CD8+ T cell-mediated protective and therapeutic effects to prolong the survival of mice with LT-expressing tumors. In the interest of determining the LT epitope which most MCC-specific CD8+ T cells recognize, we identified the amino acid sequence of the immunodominant LT epitope as aa19-27 (IAPNCYGNI) and found that it is H-2k^b-restricted.

Conclusion

The results of this study can facilitate the development of other modes of MCC treatment such as peptide-based vaccines and adoptive transfer of LT-specific CD8+ T cells. Likewise, the MCC DNA vaccine has great potential for clinical translation as the immunologic specificity is high and the treatment strategy can be exported to address other virus-induced tumors.

Mutations of p53 gene in hepatocellular-carcinoma (hcc) correlate with tumor progression and patient prognosis - a study of 138 patients with unifocal hcc

The mutation spectrum of p53 gene and its biological significance were studied in 138 patients with unifocal primary hepatocellular carcinoma (HCC) in Taiwan. The p53 mutations were detected in 51 cases (37%); 36 (71%) were missense mutations. The others (29%) included mutations at the intron-exon junctions (5 cases), deletion or insertion (4 cases), nonsense mutations (4 cases), and silent mutations (2 cases). The mutation sites were scattered from exons 4 to 10, predominantly (75%) in exons 5, 7, and 8. Of these mutations, 72% were transversions, mostly G:C --> T:A change (46%); while only 28% were transitions. Mutation occurred at codon 249 only in 14 cases (10%), but accounted for 27% of the mutations. The p53 mutations correlated with allele loss of p53 locus (52% vs 17% p<0.02), alpha-fetoprotein elevation (45% vs 28%, p<0.04), and poorly differentiated HCC (46% vs 10%, p<0.0001). The p53 mutation rate was two times higher in large than in small HCC (48% vs 26%, p<0.008), and in more advanced tumor (stage 3 vs stages 1 and 2: 49% vs 21%, p<0.0007). HCC patients with mutated p53 gene had a worse outcome (5-year survival; 18% vs 38%, p<0.008). We conclude that p53 gene mutation is common in advanced HCC, occurs as a late event in HCC growth, correlates with tumor progression and aggression, and is a useful molecular prognostic parameter of HCC. The p53 mutation patterns did not correlate with HBV or HCV infection. The frequency of p53 mutations did not differ between Taiwanese patients and mainland Chinese in Taiwan. However, mutation at codon 249 was more common in Taiwanese patients (p<0.05), while mutations of other types more frequent in the mainlanders (p<0.03). Hence endogenous and exogenous factors other than aflatoxin may also play a role in p53 mutation in HCC.

Low-dose cyclophosphamide administered as daily or single dose enhances the antitumor effects of a therapeutic HPV vaccine

Although therapeutic HPV vaccines are able to elicit systemic HPV-specific immunity, clinical responses have not always correlated with levels of vaccine-induced CD8(+) T cells in human clinical trials. This observed discrepancy may be attributable to an immunosuppressive tumor microenvironment in which the CD8(+) T cells are recruited. Regulatory T cells (Tregs) are cells that can dampen cytotoxic CD8(+) T-cell function. Cyclophosphamide (CTX) is a systemic chemotherapeutic agent, which can eradicate immune cells, including inhibitory Tregs. The optimal dose and schedule of CTX administration in combination with immunotherapy to eliminate the Treg population without adversely affecting vaccine-induced T-cell responses is unknown. Therefore, we investigated various dosing and administration schedules of CTX in combination with a therapeutic HPV vaccine in a preclinical tumor model. HPV tumor-bearing mice received either a single preconditioning dose or a daily dose of CTX in combination with the pNGVL4a-CRT/E7(detox) DNA vaccine. Both single and daily dosing of CTX in combination with vaccine had a synergistic antitumor effect as compared to monotherapy alone. The potent antitumor responses were attributed to the reduction in Treg frequency and increased infiltration of HPV16 E7-specific CD8(+) T cells, which led to higher ratios of CD8(+)/Treg and CD8(+)/CD11b(+)Gr-1(+) myeloid-derived suppressor cells (MDSCs). There was an observed trend toward decreased vaccine-induced CD8(+) T-cell frequency with daily dosing of CTX. We recommend a single, preconditioning dose of CTX prior to vaccination due to its efficacy, ease of administration, and reduced cumulative adverse effect on vaccine-induced T cells.

PD-1:PD-L1(B7-H1) pathway in adaptive resistance: A novel mechanism for tumor immune escape in human papillomavirus-related head and neck cancers

5506

Background: Human papillomavirus-associated head and neck squamous cell carcinomas (HPV-HNSCC) are associated with a strong host immune response. Despite ample tumor infiltrating lymphocytes (TILs), the cancer is able to persist and grow. Here, we provide evidence for an adaptive immune resistance mechanism mediated through the PD-1:PD-L1 pathway. Methods: We evaluated the peripheral blood and tumor infiltrating lymphocytes for PD-1 expression using flow cytometry in HPV-HNSCC patients. We evaluted PD-L1 expression within the tumors using immunohistochemistry. We performed functional assays evaluating IFN-gamma secretion of PD-1+ and PD-1(-) CD8+ T cells isolated from the tumor microenvironment of PD-L1+ and PD-L1(-) HPV-related head and neck cancers. Results: We found the majority of CD8+ TILs in HPV-HNSCC express the PD-1 co-inhibitory receptor. We report a striking association between expression of its ligand PD-L1 on tumor cells and tumor associated macrophages, and the presence of TILs. Interestingly, membranous PD-L1 staining on tumor cells and CD68+ antigen presenting cells was geographically localized to the periphery of tumor nests and juxtaposed to fronts of infiltrating T cells. Functional assays demonstrated that PD-1-dependent T cell inhibition required expression of PD-L1 in the tumor microenvironment. Finally, we report localized expression of PD-L1 in the deep crypts of normal tonsils, the site of HPV infection and origin of HPV-HNSCC. Conclusions: Our findings support the role of the PD-1:PD-L1 interaction in creating an immune-privileged site for initial viral infection and subsequently adaptive immune resistance once tumors are established and suggest a rationale for therapeutic blockade of this pathway in patients with HPV-HNSCC.

Predictors of acid suppression success in patients with chronic laryngitis

BACKGROUND

Up to 50% of the patients suspected of reflux laryngitis syndrome failed to respond to acid suppression therapy. However, predictors of acid suppression success have not been determined.

METHODS

Consecutive patients with chronic laryngitis were enrolled prospectively. All the patients underwent laryngoscopy, esophagogastroduodenoscopy and 24-h multichannel intraluminal impedance and pH (MII-pH) monitoring before receiving rabeprazole 10 mg b.i.d. for 3 months. Patient was considered as a responder to acid suppression if the chief laryngeal complaint score during the last week since last interview had decreased by at least 50% after the start of therapy compared with baseline. Cox regression analysis was used to determine the independent predictors of acid suppression success.

KEY RESULTS

Of 92 patients (age 42.4 ± 14.3 years, 50 women), 42 (45.7%) responded to acid suppression after 3 months. Gastroesophageal reflux disease was defined in 22 patients, of whom 19 patients had pathological distal esophageal acid exposure and 5 were defined as erosive esophagitis. The time to response showed a significant hazard ratio for patients with increased distal esophageal acid exposure time (β: 0.93; HR: 2.55; 95% CI: 1.24-5.24; P = 0.011) and increased laryngopharyngeal bolus exposure time (BET; β: 0.96; HR: 2.61; 95% CI: 1.36-5.00; P = 0.004). The latter had the best Youden Index (0.34) and accuracy (68.5%).

CONCLUSIONS & INFERENCES

The success of acid suppression on chronic laryngitis could be predicted using reflux parameters detected by MII-pH, among which increased laryngopharyngeal BET is the best.

Development of a DNA vaccine targeting Merkel cell polyomavirus

Merkel cell carcinoma (MCC) is a rare but devastating skin disease that is increasing in incidence within the United States. The poor prognosis of MCC patients and limited understanding of MCC pathogenesis warrants innovative treatments to control MCC. Several lines of evidence have pointed to Merkel cell polyomavirus (MCPyV) as the etiological agent of MCC. In particular, the amino terminus of MCPyV large T antigen (LT) (aa1-258) is expressed in all MCPyV-positive tumors and plays an important role in MCC oncogenesis, rendering it an ideal therapeutic target for vaccination. In the current study, we developed a DNA vaccine encoding MCPyV LT aa1-258 (pcDNA3-LT). Within our pcDNA3-LT DNA vaccine, we identified that MCPyV LT aa136-160 likely contains an LT-specific CD4+ T helper epitope. We have also created an LT-expressing B16/LT tumor model using B16, a murine melanoma cell line, to characterize the potency of our DNA vaccine. Using this tumorigenic B16/LT tumor model, we found that pcDNA3-LT DNA vaccine generates antitumor effects mainly mediated by CD4+ T cells against B16/LT tumors in vaccinated C57BL/6 mice. Thus, immunotherapy using pcDNA3-LT DNA vaccine may represent a promising approach for the control of MCPyV-associated lesions. The B16/LT tumor model further serves as a useful model for testing various vaccine strategies against MCC.

New alkaloids from the seeds of Notopterygium incisum

Three new alkaloids, N-hexacosanoylanthranilic acid (1), N-octacosanoylanthranilic acid (2) and N-eicosanoyltyramine (3), along with 19 known compounds, were isolated from the seeds of Notopterygium incisum, whose rhizomes are used as a traditional Tibetan medicine. Their structures were elucidated by 1D, 2D NMR spectra and ESI-MS spectrometer evidence.

DNA vaccines delivered by human papillomavirus pseudovirions as a promising approach for generating antigen-specific CD8+ T cell immunity

Background

Human papillomavirus (HPV) pseudovirions have recently been shown to deliver DNA efficiently in vivo, resulting in the priming of antigen-specific CD8+ T cells in vaccinated mice. In the current study, we compare the different preparation methods for the generation of HPV pseudovirions for their ability to efficiently infect cells. We also compare the antigen-specific CD8+ T cell immune responses generated by different DNA delivery methods and several commonly used forms of vaccination with that of HPV pseudovirions.

Results

We found that the preparation method of pseudovirions is important for the efficient delivery of encapsidated DNA. We have shown that vaccination with DNA encoding model antigen ovalbumin (OVA) delivered by HPV-16 pseudovirions was capable of generating therapeutic antitumor effects against OVA-expressing tumor. In addition, vaccination with DNA encoding OVA delivered by HPV-16 pseudovirions generated the highest number of OVA-specific CD8+ T cells in mice in our system compared to DNA delivered by other delivery methods. We also found that vaccination with OVA DNA delivered by HPV-16 pseudovirions generated the highest number of OVA-specific CD8+ T cells in mice compared to other forms of antigen-specific vaccines. Furthermore, HPV-16 pseudovirions were capable of carrying DNA vaccine encoding clinically relevant antigen, telomerase reverse transcriptase, to generate antigen-specific CD8+ T cell immune responses.

Conclusions

Our data suggest that DNA vaccines delivered by HPV-16 pseudovirions may be advantageous compared to other delivery methods and other forms of antigen-specific vaccines for application to antigen-specific immunotherapy.

Phase I/II study to assess safety, pharmacokinetics, and efficacy of the oral MEK 1/2 inhibitor GSK1120212 (GSK212) dosed in combination with the oral BRAF inhibitor GSK2118436 (GSK436)

CRA8503

Background: In preclinical models, the BRAF/MEK inhibitor (i) combination GSK436/GSK212 has demonstrated enhanced activity against BRAF-mutant cancer cells compared to either drug alone, delayed emergence of GSK436 resistance, and prevented proliferative skin lesions attributable to BRAFi exposure. Methods: Eligible patients (pts) had BRAF V600 mutation positive solid tumors. Part 1: pharmacokinetic (PK) drug-drug interaction (DDI) study. Part 2: Dose escalation of continuous daily dosing of the combination followed by expansion cohorts; Part 3: Randomized phase II trial in untreated stage IV melanoma. Results: 45 pts have received ≥ 1 dose of GSK212 + GSK436, including 43 melanoma (all BRAFi naïve), 1 NSCLC and 1 salivary duct carcinoma. PK results of 7 pts in Part 1 showed no effect of GSK212 on single dose of GSK436. There was no clinically meaningful DDI between GSK436 and GSK212 after repeat dosing of the combination (Part 2). GSK436 was dosed 75-150 mg BID in combination with GSK212 1.0, 1.5, 2.0 mg QD. The recommended dose was 2 mg QD GSK212 in combination with 150 mg BID GSK436. At 1.5 mg GSK212, there was one DLT, a recurrent grade (G) 2 neutrophilic panniculitis. The only G4 adverse event (AE) was a sepsis-like syndrome with fever/hypotension. G3 AEs included generalized rash (n=2, 4%) and neutropenia (n=2, 4%). Skin toxicity ≥ G2 occurred in 9 (20%) pts; of these, G2 rash (n=4, 8%) and G2 macular rash (n=1, 2%). No cutaneous squamous cell carcinoma (SCC) or hyperproliferative skin lesions have occurred at any dose level. Other common G2 toxicities were pyrexia (n=5, 11%), vomiting (n=2, 4%) and fatigue (n=2, 4%). Of 16 evaluable pts in Part 2, 13 pts had PR and 3 SD for an ORR of 81% (95% CI 54.4%-96.0%) and all but 2 pts remain on study. In 10 evaluable pts who received 150 mg BID GSK436 + ≥1 mg QD GSK212, 9 pts had PR and 1 SD. Conclusions: GSK212 at 2 mg QD combines safely with GSK436 150 mg BID, no SCC thus far and decreased frequency of rash compared to previous trials of single agent GSK436 and GSK212, respectively. The preliminary anti-tumor activity warrants further investigation; the randomized phase II trial (Part 3) is accruing.