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.

Abstract 678: Study of 2, 9-disecbutyl-1, 10-phenanthroline as a novel anticancer agent

Development of new, safe, and effective drugs or strategies targeting molecular events and pathways which are responsible for cancer initiation and progression is an urgent need to improve cancer patient care. In this study, we tested the antitumor effect of a novel agent, 2, 9-disecbutyl-1, 10-phenanthroline (dsBPT), a 1, 10-phenanthroline derivative. Both in vitro cell line and in vivo xenograft models were applied to study the antitumor efficacy and underlying mechanism of this compound. IC50s were initially determined using lung cancer cell lines: A549 (0.25 μM) and H1703 (0.1 μM), head and neck cancer cell lines: TU686 (0.08 μM) and TU212 (0.2 μM), and normal bronchial epithelial cells: BEAS-2B (2.0 μM), indicating that the growth inhibitory effect of dsBPT on cancer cell lines was about 10 times greater than that on normal human epithelial cells. Further studies demonstrated that dsBPT at a concentration of 1-2 μM induced autophagy and G1 cell cycle arrest. At higher doses between 4-8 μM, the compound further induced apoptosis (40-80%). Combination of dsBPT with the cytotoxic agent cisplatin synergistically inhibited cancer cell growth (combination index = 0.3) and induced apoptosis (80-90%) at a concentration of 1 μM for each drug. Two experiments were then performed to test dsBPT in vivo. First, xenografted mice implanted with TU212 cells were treated with three drug doses (2mg/kg, 5mg/kg, 10mg/kg). Compound was given by IV injection once per week for 3 weeks. We found that 10 mg/kg treatment significantly reduced tumor growth as compared with the control group (p = 0.004). Under the same treatment schedule, further study showed that the combination of dsBPT (2 mg/kg) with cisplatin (2 mg/kg) significantly reduced the tumor volume as compared with the untreated control (p = 0.0017), while each of the single drugs at the same concentration showed no significant inhibitory effect on tumor growth (p = 0.10 and 0.15 for cisplatin and dsBPT, respectively). Neither significant weight loss nor major organ damage was observed by histology examination in the experimental animals in this study. In summary, our study suggests that dsBPT is a novel, highly potent antitumor drug that warrants further preclinical and clinical development either as a single agent or in combination with known chemotherapy drugs such as cisplatin. (This study is supported by grants from DOD W81XWH-07-1-0306 Project 5, and GCC Distinguished Scholar Award to ZC).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 678. doi:10.1158/1538-7445.AM2011-678

Characterization of immortalized mesenchymal stem cells derived from foetal porcine pancreas

Islet replacement therapy is limited by shortage of donor islet cells. Usage of islet cells derived from porcine pancreatic stem cells (PSCs) is currently viewed as the most promising alternative for human islet transplantation. However, PSCs are rare and have a finite proliferative lifespan. In this study, we isolated and established an immortalized mesenchymal stem cell (MSC) line derived from foetal porcine pancreas, by transfecting human telomerase reverse transcriptase (hTERT) and called these immortalized pancreatic mesenchymal stem cells (iPMSCs). The iPMSCs have been cultured for more than 80 passages and have capacity to differentiate into neurons, cardiomyocytes, germ cells and islet-like cells, analysed by morphology, RT-PCR, western blotting, immunofluorescence, immunocytochemistry and transplantation assay. Islets derived from iPMSCs reversed hyperglycaemia in streptozotocin-induced diabetic mice and secreted insulin and C-peptide in vitro. These results demonstrated that iPMSCs might provide unlimited resources for islet replacement therapy and models for functional cell differentiation.

Innovative DNA vaccine for human papillomavirus (HPV)-associated head and neck cancer

Human papillomavirus (HPV), particularly type 16, has been associated with a subset of head and neck cancers. The viral-encoded oncogenic proteins E6 and E7 represent ideal targets for immunotherapy against HPV-associated head and neck cancers. DNA vaccines have emerged as attractive approaches for immunotherapy due to its simplicity, safety, and ease of preparation. Intradermal administration of DNA vaccine via gene gun represents an efficient method to deliver DNA directly into dendritic cells for priming antigen-specific T cells. We have previously shown that a DNA vaccine encoding an invariant chain (Ii), in which the class II-associated Ii peptide (CLIP) region has been replaced by a Pan-DR-epitope (PADRE) sequence to form Ii-PADRE, is capable of generating PADRE-specific CD4+ T cells in vaccinated mice. In the current study, we hypothesize a DNA vaccine encoding Ii-PADRE linked to E6 (Ii-PADRE-E6) will further enhance E6-specific CD8+ T cell immune responses through PADRE-specific CD4+ T helper cells. We found that mice vaccinated with Ii-PADRE-E6 DNA generated comparable levels of PADRE-specific CD4+ T cell immune responses as well as significantly stronger E6-specific CD8+ T cell immune responses and antitumor effects against the lethal challenge of E6-expressing tumor compared to mice vaccinated with Ii-E6 DNA. Taken together, our data indicates that vaccination with Ii-E6 DNA with PADRE replacing the CLIP region is capable of enhancing the E6-specific CD8+ T cell immune response generated by the Ii-E6 DNA. Thus, Ii-PADRE-E6 represents a novel DNA vaccine for the treatment of HPV-associated head and neck cancer and other HPV-associated malignancies.

Enhanced anti-tumor activity by the combination of the natural compounds (-)-epigallocatechin-3-gallate and luteolin: potential role of p53

Natural dietary agents have drawn a great deal of attention toward cancer prevention because of their wide safety margin. However, single agent intervention has failed to bring the expected outcome in clinical trials; therefore, combinations of chemopreventive agents are gaining increasingly popularity. In the present study, we investigated a combinatorial approach using two natural dietary polyphenols, luteolin and EGCG, and found that their combination at low doses (at which single agents induce minimal apoptosis) synergistically increased apoptosis (3-5-fold more than the additive level of apoptosis) in both head and neck and lung cancer cell lines. This combination also significantly inhibited growth of xenografted tumors in nude mice. The in vivo findings also were supported by significant inhibition of Ki-67 expression and increase in TUNEL-positive cells in xenografted tissues. Mechanistic studies revealed that the combination induced mitochondria-dependent apoptosis in some cell lines and mitochondria-independent apoptosis in others. Moreover, we found more efficient stabilization and ATM-dependent Ser(15) phosphorylation of p53 due to DNA damage by the combination, and ablation of p53 using shRNA strongly inhibited apoptosis as evidenced by decreased poly(ADP-ribose) polymerase and caspase-3 cleavage. In addition, we observed mitochondrial translocation of p53 after treatment with luteolin or the combination of EGCG and luteolin. Taken together, our results for the first time suggest that the combination of luteolin and EGCG has synergistic/additive growth inhibitory effects and provides an important rationale for future chemoprevention trials of head and neck and lung cancers.

Abstract 5649: Highly synergistic anti-tumor efficacy induced by the combination of two natural dietary agents, luteolin and EGCG: Role of p53 phosphorylation, stabilization and translocation

Natural dietary agents have drawn a great deal of attention for cancer prevention and therapy because of their wide safety margin and easy availability. However, single agent intervention has failed to bring the expected outcome in clinical trials in many instances; therefore, combinations of chemopreventive agents are gaining increasing attention. In the present study, we have investigated a combinatorial approach using two natural dietary polyphenols, luteolin and EGCG, and found that combination of the two compounds at low doses (at which almost no apoptosis was observed after single agent treatment) tremendously increased apoptosis (50-70%) in both head and neck and lung cancer cell lines (a panel of 11 cell lines tested). This combination also significantly inhibited growth of head and neck cancer Tu212 and lung cancer A549 xenografts as compared with either of the single agents (P value < 0.05). Ki-67 and TUNEL staining of the xenografted tumor tissues also showed statistically significant decrease in the number of Ki-67 and increase in TUNEL positive cells after combined treatment with luteolin and EGCG as compared with single agent treatment or untreated control. Further mechanistic study showed that the combination-induced both mitochondria-dependent and -independent apoptosis varying among cell lines. Although the combination was effective against cell lines regardless of their p53 status, those with wild-type p53 were much more sensitive to the treatment than those with mutant or no p53. Ablation of p53 using shRNA strongly inhibited apoptosis (>50%) as evidenced by decreased PARP and caspase 3 cleavage. Moreover, we found more efficient stabilization and phosphorylation of p53 at Ser15 by the combination as compared with either single agent, particularly when the basal p53 levels were low. In addition, we observed mitochondrial translocation of p53 after treatment with luteolin or the combination of EGCG and luteolin. Taken together, our results, for the first time, suggest that combination of luteolin and EGCG has synergistic/additive growth inhibitory effects both in vitro and in vivo via a p53-dependent pathway and will provide an important rationale for chemoprevention or treatment trials using this combination. This research was supported by the National Cancer Institute award 5 P50 CA128613 SPORE in Head and Neck Cancer (ARA, JCB, TM, FRK, ZGC and DMS).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5649.

Pluripotency factors Lin28 and Oct4 identify a sub-population of stem cell-like cells in ovarian cancer

Lin28 and Oct4 are highly expressed in human embryonic stem (ES) cells and, along with two other stem cell marker proteins (Nanog and Sox2), together can convert human somatic cells to pluripotency. As an RNA-binding protein, Lin28 acts to stimulate the translation of a specific subset of mRNAs, and to inhibit the biogenesis of a group of microRNAs. Oct4 is a transcription factor essential for the maintenance of pluripotency and survival of ES cells. In this study, we report that a sub-population of epithelial ovarian cancer (EOC) cells co-expresses Lin28 and Oct4 as demonstrated in the analyses of both cell lines and patient tumor samples. We also observe that the combined expression of these proteins in tumor samples is correlated with advanced tumor grade. Intriguingly, when the expression of these two proteins is repressed in the same cells using RNA interference, there is significant reduction in cell growth and survival. We thus propose that Lin28 and Oct4 may have important roles in the initiation and/or progression of EOC, and consequently may serve as important molecular diagnostics and/or therapeutic targets for the development of novel treatment strategies in EOC patients.

Prevalence of erosive esophagitis and Barrett's esophagus in the adult Chinese population

BACKGROUND AND STUDY AIM

The aim of this study was to determine the prevalence, characteristics, and risk factors of erosive esophagitis and Barrett's esophagus in an adult Chinese population without gastroesophageal reflux symptoms.

PATIENTS AND METHODS

Between March 2006 and February 2007, consecutive individuals aged between 18 and 75 years, who underwent routine upper endoscopy as part of their regular medical examination were recruited. Demographic and medical information were collected. Erosive esophagitis was defined endoscopically as visible breaks of the distal esophageal mucosa. Barrett's esophagus was diagnosed endoscopically and confirmed histologically. "Silent GERD" was defined when erosive esophagitis and/or Barrett's esophagus were present in an individual without reflux symptoms.

RESULTS

Among the 2580 individuals included, erosive esophagitis and Barrett's esophagus were found in 4.3 % (n = 110) and 1.0 % (n = 27), respectively. In individuals with erosive esophagitis and Barrett's esophagus, 33.6 % and 40.7 %, respectively, were asymptomatic. Thus, the prevalence of erosive esophagitis and Barrett's esophagus in individuals without GERS was 1.6 % and 0.5 %, respectively, giving an overall prevalence of silent GERD of 2.0 % (46 / 2270). Multivariate analysis identified that male sex (odds ratio [OR] = 2.87, 95 % confidence interval [CI] 1.24 - 6.66; P = 0.014), hiatus hernia (OR = 9.68, 95 %CI 5.00 - 17.95; P < 0.001), and alcohol consumption (OR = 3.17, 95 %CI 1.44 - 6.97; P = 0.004) were positively associated with erosive esophagitis, whereas Helicobacter Pylori infection (OR = 0.37, 95 %CI 0.14 - 0.98; P = 0.046) was negatively associated with erosive esophagitis. Alcohol consumption (OR = 5.32, 95 %CI 1.55 - 13.33; P = 0.008) was positively associated with Barrett's esophagus in asymptomatic individuals.

CONCLUSION

In this cohort of the adult Chinese population without reflux symptoms, the prevalence of erosive esophagitis and Barrett's esophagus is 1.6 % and 0.5 %, respectively, with an overall prevalence of silent GERD of 2.0 %. Male sex, hiatus hernia, and alcohol consumption are positively associated with erosive esophagitis, whereas a negative association exists for H. pylori infection. Alcohol consumption is positively associated with Barrett's esophagus.

Response of aged parkinsonian monkeys to in vivo gene transfer of GDNF

This study assessed the potential for functional and anatomical recovery of the diseased aged primate nigrostriatal system, in response to trophic factor gene transfer. Aged rhesus monkeys received a single intracarotid infusion of MPTP, followed one week later by MRI-guided stereotaxic intrastriatal and intranigral injections of lentiviral vectors encoding for glial derived neurotrophic factor (lenti-GDNF) or beta-galactosidase (lenti-LacZ). Functional analysis revealed that the lenti-GDNF, but not lenti-LacZ treated monkeys displayed behavioral improvements that were associated with increased fluorodopa uptake in the striatum ipsilateral to lenti-GDNF treatment. GDNF ELISA of striatal brain samples confirmed increased GDNF expression in lenti-GDNF treated aged animals that correlated with functional improvements and preserved nigrostriatal dopaminergic markers. Our results indicate that the aged primate brain challenged by MPTP administration has the potential to respond to trophic factor delivery and that the degree of neuroprotection depends on GDNF levels.

Carbon nanotube reservoirs for self-healing materials

A novel nanoreservoir made of carbon nanotubes (CNTs) is proposed for realizing tougher and automated self-healing materials. The advantages of the approach are that CNTs have the potential to play the role of reinforcing elements prior to and after sealing a crack and that the number of voids is reduced after the material and the CNTs themselves are healed. The focus of this paper is on investigating the feasibility of using CNTs as a nanoreservoir by analyzing the dynamics of a fluid flowing out of a ruptured single-walled CNT (SWNT), where the fluid resembles an organic healing agent. With this in mind the escaping mechanism of organic molecules stored inside a cracked SWNT was investigated through a molecular dynamics study. The study shows that, when a SWNT wall suffers the formation of a crack, a certain amount of organic molecules, stored inside the SWNT, escape into space in a few picoseconds. This phenomenon is found to depend on the temperature and on the size of the cracks. The results of this study indicate that CNTs have the potential to be successfully used to realize the next generation of stronger, lighter and self-healing materials.

Increased frequencies of T helper type 17 cells in the peripheral blood of patients with acute myeloid leukaemia

T helper type 17 (Th17) cells, which represent a novel subset of CD4(+) T cells, play an active role in inflammatory and autoimmune diseases. Recent studies have also suggested that they have an impact on solid tumours. However, the nature of Th17 cells in haematological malignancies remains unknown. In this study, we investigated Th17 cell frequency and secretion of related cytokines in patients with acute myeloid leukaemia (AML). First, we found that Th17 cell frequencies were increased significantly in peripheral blood samples from untreated patients with AML, compared with those from healthy volunteers. Moreover, increased interleukin (IL)-17 concentrations accompanied the increased Th17 cell frequencies in these patients. These results suggest that Th17 cells may play a role in the pathogenesis of AML. Secondly, we found that the increased Th17 cell frequencies were reduced when patients achieved complete remission after chemotherapy, suggesting that measurement of Th17 cell frequencies may have clinical value in the evaluation of therapeutic effect. In addition, we found that IL-6 and transforming growth factor (TGF)-beta1 concentrations increased in the untreated patients and that IL-6 concentrations showed a positive correlation with the frequencies of Th17 cells, suggesting that IL-6 may play an important role in Th17 cell differentiation in patients with AML.

Abnormal striatal and thalamic dopamine neurotransmission: Genotype-related features of dystonia

OBJECTIVE

To determine whether changes in D(2) receptor availability are present in carriers of genetic mutations for primary dystonia.

METHODS

Manifesting and nonmanifesting carriers of the DYT1 and DYT6 dystonia mutations were scanned with [(11)C] raclopride (RAC) and PET. Measures of D(2) receptor availability in the caudate nucleus and putamen were determined using an automated region-of-interest approach. Values from mutation carriers and healthy controls were compared using analysis of variance to assess the effects of genotype and phenotype. Additionally, voxel-based whole brain searches were conducted to detect group differences in extrastriatal regions.

RESULTS

Significant reductions in caudate and putamen D(2) receptor availability were evident in both groups of mutation carriers relative to healthy controls (p < 0.001). The changes were greater in DYT6 relative to DYT1 carriers (-38.0 +/- 3.0% vs -15.0 +/- 3.0%, p < 0.001). By contrast, there was no significant difference between manifesting and nonmanifesting carriers of either genotype. Voxel-based analysis confirmed these findings and additionally revealed reduced RAC binding in the ventrolateral thalamus of both groups of mutation carriers. As in the striatum, the thalamic binding reductions were more pronounced in DYT6 carriers and were not influenced by the presence of clinical manifestations.

CONCLUSIONS

Reduced D(2) receptor availability in carriers of dystonia genes is compatible with dysfunction or loss of D(2)-bearing neurons, increased synaptic dopamine levels, or both. These changes, which may be present to different degrees in the DYT1 and DYT6 genotypes, are likely to represent susceptibility factors for the development of clinical manifestations in mutation carriers.

Transcutaneous electroacupuncture improves dyspeptic symptoms and increases high frequency heart rate variability in patients with functional dyspepsia

The aim of the study was to evaluate the therapeutic value and possible mechanisms of transcutaneous electroacupuncture (TEA) in a double-blind and cross-over study in patients with functional dyspepsia (FD). Twenty-seven patients with FD were enrolled and the study consisted of two parts: (i) acute effects of TEA at PC6 and ST36 on gastric slow waves and heart rate variability and (ii) chronic (2 weeks) effects of TEA at PC6 and ST36 on dyspepsia symptoms, gastric slow waves, heart rate variability and neuropeptide Y (NPY) and motilin. The results of this study are: (i) The dyspepsia symptom score was decreased by 55% at the end of chronic TEA and the improvement was significant (P < 0.01); (ii) the high frequency (HF) assessed from the spectral analysis of heart rate variability was markedly increased with both acute TEA (76% increase, P = 0.01) and chronic TEA (75% increase, P = 0.025); (iii) gastric slow waves were not altered by either acute or chronic TEA; and (iv) the plasma level of NPY but not motilin was increased after chronic TEA. Non-invasive and needleless transcutaenous electroacupuncture at ST36 and PC6 markedly improves dyspepsia symptoms and the improvement may be associated with the increase in HF heart rate variability and the modulation of NPY.

Cluster intradermal DNA vaccination rapidly induces E7-specific CD8+ T-cell immune responses leading to therapeutic antitumor effects

Intradermal administration of DNA vaccines via a gene gun represents a feasible strategy to deliver DNA directly into the professional antigen-presenting cells (APCs) in the skin. This helps to facilitate the enhancement of DNA vaccine potency via strategies that modify the properties of APCs. We have previously demonstrated that DNA vaccines encoding human papillomavirus type 16 (HPV-16) E7 antigen linked to calreticulin (CRT) are capable of enhancing the E7-specific CD+ T-cell immune responses and antitumor effects against E7-expressing tumors. It has also been shown that cluster (short-interval) DNA vaccination regimen generates potent immune responses in a minimal time frame. Thus, in the current study we hypothesize that the cluster intradermal CRT/E7 DNA vaccination will generate significant antigen-specific CD8+ T-cell infiltrates in E7-expressing tumors in tumor-bearing mice, leading to an increase in apoptotic tumor cell death. We found that cluster intradermal CRT/E7 DNA vaccination is capable of rapidly generating a significant number of E7-specific CD8+ T cells, resulting in significant therapeutic antitumor effects in vaccinated mice. We also observed that cluster intradermal CRT/E7 DNA vaccination in the presence of tumor generates significantly higher E7-specific CD8+ T-cell immune responses in the systemic circulation as well as in the tumors. In addition, this vaccination regimen also led to significantly lower levels of CD4+Foxp3+ T-regulatory cells and myeloid suppressor cells compared to vaccination with CRT DNA in peripheral blood and in tumor-infiltrating lymphocytes, resulting in an increase in apoptotic tumor cell death. Thus, our study has significant potential for future clinical translation.

Trends in leaf photosynthesis in historical rice varieties developed in the Philippines since 1966

Crop improvement in terms of yield is rarely linked to leaf photosynthesis. However, in certain crop plants such as rice, it is predicted that an increase in photosynthetic rate will be required to support future grain yield potential. In order to understand the relationships between yield improvement and leaf photosynthesis, controlled environment conditions were used to grow 10 varieties which were released from the International Rice Research Institute (IRRI) between 1966 and 1995 and one newly developed line. Two growth light intensities were used: high light (1500 micromol m(-2) s(-1)) and low light (300 micromol m(-2) s(-1)). Gas exchange, leaf protein, chlorophyll, and leaf morphology were measured in the ninth leaf on the main stem. A high level of variation was observed among high light-grown plants for light-saturated photosynthetic rate per unit leaf area (P(max)), stomatal conductance (g), content of ribulose bisphosphate carboxylase-oxygenase (Rubisco), and total leaf protein content. Notably, between 1966 and 1980 there was a decline in P(max), g, leaf protein, chlorophyll, and Rubisco content. Values recovered in those varieties released after 1980. This striking trend coincides with a previous published observation that grain yield in IRRI varieties released prior to 1980 correlated with harvest index whereas that for those released after 1980 correlated with biomass. P(max) showed significant correlations with both g and Rubisco content. Large differences were observed between high light- and low light-grown plants (photoacclimation). The photoacclimation 'range' for P(max) correlated with P(max) in high light-grown plants. It is concluded that (i) leaf photosynthesis may be systematically affected by breeding strategy; (ii) P(max) is a useful target for yield improvements where yield is limited by biomass production rather than partitioning; and (iii) the capacity for photoacclimation is related to high P(max) values.

A combination of DNA vaccines targeting human papillomavirus type 16 E6 and E7 generates potent antitumor effects

Human papillomavirus (HPV) infects large numbers of women worldwide and is present in more than 99% of all cervical cancers. HPV E6 and E7 are two viral oncoproteins that are consistently expressed in HPV infections and HPV-associated malignancies. We have previously developed DNA vaccines encoding calreticulin (CRT) linked either to HPV type 16 (HPV-16) E6 or to HPV-16 E7, both of which generated significant antitumor effects against E6- and E7-expressing tumors. In this study, we demonstrate that simultaneous vaccination of C57BL/6 mice or HLA-A2 transgenic mice with both CRT/E6 and CRT/E7 DNA vaccines generates significant E6- and E7-specific T-cell immune responses in vaccinated mice. Furthermore, combined vaccination with both CRT/E6 and CRT/E7 DNA generates significantly better therapeutic antitumor effects against HPV E6- and E7-expressing tumors than vaccination with either CRT/E6 DNA or CRT/E7 DNA alone. Our data suggest that it may be desirable to combine DNA vaccines targeting E6 with DNA vaccines targeting E7 to develop effective immunotherapeutic strategies for control of HPV infection and HPV-associated lesions in a clinical setting.