Abstract 5202: AMG 794, a Claudin 6-targeted half-life extended (HLE) bispecific T cell engager (BITE®) molecule for non-small cell lung cancer and epithelial ovarian cancer

AMG 794 is a half-life extended BiTE® immune therapy targeting the oncofetal antigen Claudin 6 (CLDN6). AMG 794 redirects T cells to kill CLDN6-expressing tumor cells and is being developed for the treatment of non-small cell lung cancer (NSCLC) and epithelial ovarian cancer (EOC). CLDN6 is a compelling tumor antigen that is expressed during embryonic and fetal development, transcriptionally silenced in adult tissues, and re-expressed on the surface of NSCLC and EOC cells. By immunohistochemistry, CLDN6 staining of the cell membrane was observed in 27% of non-squamous NSCLC (n = 63) and 69% of EOC (n = 92) samples, the majority of which were of the high-grade serous ovarian cancer subtype. Expression of CLDN6 protein was not detected in most normal adult tissues, with rare CLDN6 immunostaining limited to individual cells in the pituitary, pancreas, small intestine, kidney, and female reproductive organs. AMG 794 is a fully human BiTE® molecule that binds both human and cynomolgus monkey CLDN6 and CD3. AMG 794 binds human CLDN6 and CD3 with equilibrium dissociation constant (KD) of 13 nM and 36 nM, respectively. In vitro, AMG 794 redirects human T cells to kill CLDN6-expressing cancer cells with a half-maximal lysis concentration (EC50) of 2.6 ± 1.1 pM to 127.4 ± 53.4 pM. Consistent with the mechanism of action of BiTE® immune therapy, AMG 794 induces T cell activation and transient production of cytokines in co-cultures of T cells and CLDN6-expressing tumor cells. Remarkably, AMG 794 binding and cytotoxic activity is selective for CLDN6 over other claudin family proteins, despite high homology in the extracellular loops with CLDN9. Weekly dosing of AMG 794 significantly inhibited the growth of established lung and ovarian xenograft tumors in immunocompromised mice injected with human T cells. Anti-tumor activity was associated with an increase in tumor-infiltrating T cells. AMG 794 was well tolerated in a one-month repeat-dose toxicology study in cynomolgus monkey, with evidence for target engagement. The potent, selective activity of AMG 794 for CLDN6-expressing NSCLC and EOC cells, together with an acceptable nonclinical safety profile, supported the advancement of AMG 794 into clinical development. A first-in-human study to explore the safety, tolerability, pharmacokinetics, and anti-tumor activity of AMG 794 in patients with CLDN6-positive advanced/metastatic non-squamous NSCLC or EOC will be enrolling patients in March 2022.

Citation Format: Elizabeth Pham, Anja Henn, Beate Sable, Joachim Wahl, Kip Conner, Katja Matthes, Shivani Gupta, Rodolfo Yabut, Famke Aeffner, Kristin Lewis Wilson, Jonas Anlahr, Christoph Dahlhoff, Vijay Kale, Matthias Friedrich, Tobias Raum, Peter Kufer, Angela Coxon, Sabine Stienen, Julie M. Bailis. AMG 794, a Claudin 6-targeted half-life extended (HLE) bispecific T cell engager (BITE®) molecule for non-small cell lung cancer and epithelial ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5202.

Unexplored nutritive potential of tomato to combat global malnutrition

Tomato, a widely consumed vegetable crop, offers a real potential to combat human nutritional deficiencies. Tomatoes are rich in micronutrients and other bioactive compounds (including vitamins, carotenoids, and minerals) that are known to be essential or beneficial for human health. This review highlights the current state of the art in the molecular understanding of the nutritional aspects, conventional and molecular breeding efforts, and biofortification studies undertaken to improve the nutritional content and quality of tomato. Transcriptomics and metabolomics studies, which offer a deeper understanding of the molecular regulation of the tomato's nutrients, are discussed. The potential uses of the wastes from the tomato processing industry (i.e., the peels and seed extracts) that are particularly rich in oils and proteins are also discussed. Recent advancements with CRISPR/Cas mediated gene-editing technology provide enormous opportunities to enhance the nutritional content of agricultural produces, including tomatoes. In this regard, genome editing efforts with respect to biofortification in the tomato plant are also discussed. The recent technological advancements and knowledge gaps described herein aim to help explore the unexplored nutritional potential of the tomato.

Losartan attenuates progression of osteoarthritis in the synovial temporomandibular and knee joints of a chondrodysplasia mouse model through inhibition of TGF-β1 signaling pathway

OBJECTIVE

Transforming growth factor beta 1 (TGF-β1) is implicated in osteoarthritis (OA). The purpose of this study was to explore the ability of Losartan to inhibit the inflammatory signaling pathway of TGF-β1 observed during osteoarthritic progression in the temporomandibular joint (TMJ) and knee joint using a genetic mouse model.

METHODS

A murine OA model displaying the heterozygous chondrodysplasia gene (cho/+), a col11a1 mutation, was used to test this hypothesis. Following a 7-month treatment period with Losartan, the synovial joints were analyzed for histopathological improvement comparing two experimental groups. Tissues were fixed in paraformaldehyde, processed to paraffin section, and stained with Safranin O and Fast Green to visualize proteoglycans and collagen proteins in cartilage. Using the Modified Mankin scoring system, the degree of staining and OA progression were evaluated.

RESULTS

Results show heterozygous animals receiving Losartan having diminished degeneration of TMJ condylar and knee joint articular cartilage. This was confirmed in the TMJ and knee by a statistically significant decrease in the Mankin histopathology score. Decreased expression of HtrA1, a key regulator to the TGF-β1 signaling pathway, was demonstrated in vitro as well as in vivo, via Losartan inhibition.

CONCLUSION

Using a genetic mouse model of OA, this study demonstrated the utility of Losartan to improve treatment of human OA in the TMJ and knee joint through inhibition of the TGF-β1 signaling cascade. We further demonstrated inhibition of HtrA1, the lowering of Mankin scores to wild type control levels, and the limiting of OA progressive damage with treatment of Losartan.

Abstract 2933: The apoptotic mechanism of action of SKI-178, a novel Sphingosine kinase 1 selective inhibitor

We previously developed SKI-178 as a novel Sphingosine kinase 1 (SphK1) selective inhibitor that is cytotoxic toward a broad panel of cancer types. Herein, we sought to determine the mechanism-of-action of SKI-178-induced cell death. We present evidence that SKI-178 induces prolonged mitosis followed by apoptotic cell death through the intrinsic apoptotic cascade. Further examination of the mechanism-of-action (MOA) of SKI-178 implicated c-Jun NH2-terminal kinase (JNK) and cyclin-dependent protein kinase 1 (CDK1) as critical factors required for SKI-178-induced apoptosis. In cell cycle synchronized human AML cell lines, we demonstrate that entry into mitosis is required for apoptotic induction by SKI-178 and that CDK1, not JNK, is required for SKI-178-induced apoptosis. We further demonstrate that the sustained activation of CDK1 during prolonged mitosis, mediated by SKI-178, leads to the simultaneous phosphorylation of the pro-survival Bcl-2 family members, Bcl-2 and Bcl-xl, as well as the phosphorylation and subsequent degradation of Mcl-1. Moreover, multi-drug resistance mediated by MDR-1 and/or pro-survival Bcl-2 family member over-expression did not affect the sensitivity of AML cells to SKI-178. In addition to AML, we extend the MOA of SKI-178 to include various solid tumor cell lines, including pancreatic cancer and glioblastoma. Taken together, we provide evidence that SKI-178 induces apoptosis in a CDK1-dependent manner and is not a substrate for MDR1, making it a promising chemotherapeutic candidate for the treatment of various cancer types, including those known to be drug resistant.

Citation Format: Taryn E. Dick, Jeremy Hengst, Vijay Kale, Ashley Colledge, Jong K. Yun. The apoptotic mechanism of action of SKI-178, a novel Sphingosine kinase 1 selective inhibitor. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2933. doi:10.1158/1538-7445.AM2015-2933

Gene-directed enzyme prodrug therapy

As one targeting strategy of prodrug delivery, gene-directed enzyme prodrug therapy (GDEPT) promises to realize the targeting through its three key features in cancer therapy-cell-specific gene delivery and expression, controlled conversion of prodrugs to drugs in target cells, and expanded toxicity to the target cells' neighbors through bystander effects. After over 20 years of development, multiple GDEPT systems have advanced into clinical trials. However, no GDEPT product is currently marketed as a drug, suggesting that there are still barriers to overcome before GDEPT becomes a standard therapy. In this review, we first provide a general introduction of this prodrug targeting strategy. Then, we utilize the four most thoroughly studied systems to illustrate components, mechanisms, preclinical and clinical results, and further development directions of GDEPT. These four systems are herpes simplex virus thymidine kinase/ganciclovir, cytosine deaminase/5-fluorocytosine, cytochrome P450/oxazaphosphorines, and nitroreductase/CB1954 system. Later, we focus our discussion on bystander effects including local and distant bystander effects. Lastly, we discuss carriers that are used to deliver genes for GDEPT including virus carriers and non-virus carriers. Among these carriers, the stem cell-based gene delivery system represents one of the newest carriers under development, and may brought about a breakthrough to the gene delivery issue of GDEPT.

Near-infrared excited ultraviolet emitting upconverting phosphors as an internal light source in dry chemistry test strips for glucose sensing

UV-emitting upconverting nanophosphors can be used as an internal light source in test strips for glucose measurement.

Evaluation of adverse effects of lisinopril and rosuvastatin on hematological and biochemical analytes in wistar rats

Objective:

Combination therapy of lisinopril and rosuvastatin may be an important concept in developing more effective strategies to treat and prevent atherosclerosis, coronary heart disease, and co-morbid metabolic disorders. The present study was designed to evaluate toxic effects of lisinopril and rosuvastatin alone or its combination therapy on hematological and biochemical analytes in Wistar rats.

Materials and Methods:

Forty-two rats were divided into seven groups, with each group comprising six rats. Rats were administered with lisinopril, rosuvastatin alone, or in-combination at two different doses. The blood samples were collected from rats after 21 days of oral administration of the drug/s and analyzed for various hematological and biochemical analytes.

Results:

Lisinopril alone and its combination treatment with rosuvastatin at high doses decreased hemoglobin and hematocrit. Rosuvastatin alone at high dose and its concomitant administration with lisinopril at two different doses showed increase in total white blood cells and absolute lymphocyte count and neutrophil count. Serum levels of aspartate aminotransferase (AST), alkaline phosphatase (ALP), and total bilirubin were significantly increased in rosuvastatin alone and its combination with lisinopril at both the doses. Besides this, lisinopril treatment decreased serum levels of sodium and increased the levels of potassium. Serum creatine kinase (CK) levels were increased in the animals treated with rosuvastatin at both the doses. However, increased serum CK level because of rosuvastatin became normal with co-administration of lisinopril at low doses.

Conclusion:

Our results indicate that administration of lisinopril with rosuvastatin does not ameliorate hepatotoxicity caused by rosuvastatin. However, combination treatment reduces serum CK levels elevated due to rosuvastatin, implicating protective effect of combination treatment on myopathy at low doses.

Clinical response of newly diagnosed HIV seropositive & seronegative pulmonary tuberculosis patients with the RNTCP Short Course regimen in Pune, India

BACKGROUND & OBJECTIVES

In the Revised National Tuberculosis Control Programme (RNTCP) in India prior to 2005, TB patients were offered standard DOTS regimens without knowledge of HIV status. Consequently such patients did not receive anti-retroviral therapy (ART) and the influence of concomitant HIV infection on the outcome of anti-tuberculosis treatment remained undetermined. This study was conducted to determine the results of treatment of HIV seropositive pulmonary tuberculosis patients with the RNTCP (DOTS) regimens under the programme in comparison with HIV negative patients prior to the availability of free ART in India.

METHODS

Between September 2000 and July 2006, 283 newly diagnosed pulmonary TB patients were enrolled in the study at the TB Outpatient Department at the Talera Hospital in the Pimpri Chinchwad Municipal Corporation area at Pune (Maharashtra): they included 121 HIV seropositive and 162 HIV seronegative patients. They were treated for tuberculosis as per the RNTCP in India. This study was predominantly conducted in the period before the free ART become available in Pune.

RESULTS

At the end of 6 months of anti-TB treatment, 62 per cent of the HIV seropositive and 92 per cent of the HIV negative smear negative patients completed treatment and were asymptomatic; among smear positive patients, 70 per cent of the HIV-seropositive and 81 per cent of HIV seronegative pulmonary TB patients were cured. Considering the results in the smear positive and smear negative cases together, treatment success rates were substantially lower in HIV positive patients than in HIV negative patients, (66% vs 85%). Further, 29 per cent of HIV seropositive and 1 per cent of the HIV seronegative patients expired during treatment. During the entire period of 30 months, including 6 months of treatment and 24 months of follow up, 61 (51%) of 121 HIV positive patients died; correspondingly there were 6 (4%) deaths among HIV negative patients.

INTERPRETATION & CONCLUSIONS

The HIV seropositive TB patients responded poorly to the RNTCP regimens as evidenced by lower success rates with chemotherapy and high mortality rates during treatment and follow up. There is a need to streamline the identification and management of HIV associated TB patients in the programme with provision of ART to achieve high cure rates for TB, reducing mortality rates and ensuring a better quality of life.

Studies on the antigenic specificity of Mycobacterium leprae. III. Further studies on immunological characterization

The ability of the various protein antigens of Mycobacterium leprae to induce as well as detect delayed type hypersensitivity has been confirmed by studies in mice. Additionally, one of the fractions obtained from untreated M. leprae has been shown to possess specificity to the organism through immuno-analysis, thus confirming previous observations on skin-reactivity in guinea pigs. SDS-PAG electrophoresis has shown that this fraction contains a single antigen. A suggestion has been made that this single protein could be a target antigen for early diagnosis of leprosy, specifically in contacts of leprosy patients. It could also assist in detecting a latent infection. Additional studies, using different parameters, should lead to further confirmation of its specificity. It has also been suggested that such M. leprae-specific protein antigens could play an important role in the immune response of leprosy patients. They could also have a significant impact as possible immuno-protective agents, either by themselves or in combination with other immuno-potentiating agents.

Studies on the antigenic specificity of Mycobacterium leprae. II. Immunological characterization

Antigens from untreated and autoclaved Mycobacterium leprae obtained through chromatofocusing were tested for their ability to both induce as well as elicit skin reactivity in guinea pigs sensitized either with homologous and heterologous mycobacteria or with the fractions derived from autoclaved M. leprae. In former studies, of the several antigen-positive fractions, one showed specific activity and the remaining others cross-reactivity, as indicated by studies of hypersensitivity. The fraction exhibiting specificity contained only one antigen, whereas the other fractions contained more than one antigen. Because of the technique employed, all the fractions contained antigens that were proteinic in nature. In the latter studies, the antigens obtained from autoclaved M. leprae were shown to possess sensitizing capabilities, in addition to induction properties. Two fractions from untreated M. leprae had antigens that were heat-labile, whereas the remaining fractions contained heat-stable antigens.

Studies on the antigenic specificity of Mycobacterium leprae. I. Isoelectric and chromatofocusing separation

Cell sonicates of Mycobacterium leprae and other mycobacteria were subjected to isoelectric focusing and chromatofocusing to evaluate their protein antigens and to determine if the patterns were significantly different. Isoelectric focusing showed that the proteins of all mycobacteria focused within the pH range of 3.5 to 5.5, except those of M. leprae which extended beyond 5.5 to 6.5. These studies have indicated for the first time that the protein antigens of mycobacteria are acidic in nature. Comparison between the proteins of untreated and autoclaved M. leprae showed distinct differences between the two preparations, in respect of loss of some antigens in the autoclaved M. leprae sonicate. This indicates that the bands that were not visible in the autoclaved M. leprae were those of heat-labile proteins. It is possible, however, that the absent bands could have been of a low order of intensity and hence were not discernible. On the other hand, the proteins could have coagulated due to the heat treatment, thus causing confirmational changes or ionic interactions with membrane components, due to their acidic nature. It is possible that the proteins in the autoclaved M. leprae are the ones that possess immunogenic properties since the protective ability of heat-killed M. leprae has already been established. Chromatofocusing studies have confirmed the isoelectric focusing data in respect of the number of antigens and their respective protein content, besides permitting the availability of the various fractions for further biological characterization.