Relationship of microsatellite instability to mismatch repair deficiency in malignant tumors of dogs

BACKGROUND

Microsatellite instability (MSI) is a type of genomic instability caused by mismatch repair deficiency (dMMR) in tumors. Studies on dMMR/MSI are limited, and the relationship between dMMR and MSI is unknown in tumors of dogs.

OBJECTIVES

We aimed to identify the frequency of dMMR/MSI by tumor type and evaluate the relationship between dMMR and MSI in tumors of dogs.

ANIMALS

In total, 101 dogs with 11 types of malignant tumors were included.

METHODS

We extracted DNA from fresh normal and tumor tissues. Twelve microsatellite loci from both normal and tumor DNA were amplified by PCR and detected by capillary electrophoresis. Each microsatellite (MS) was defined as MSI if a difference in product size between the tumor and normal DNA was detected. The dMMR was evaluated by immunohistochemistry with formalin-fixed paraffin-embedded tumor tissues. Next, we confirmed whether dMMR induces MSI by serial passaging of MMR gene knockout cell lines for 3 months.

RESULTS

Microsatellite instability was detected frequently in oral malignant melanoma. The number of MSI-positive markers was higher in cases with dMMR than in those with proficient MMR (P < .0001). Statistical analysis indicated that the occurrence of MSI in FH2305 might have relevance to dMMR. Furthermore, MSI occurred in dMMR cell lines 3 months after passaging.

CONCLUSIONS AND CLINICAL IMPORTANCE

Microsatellite instability and dMMR more frequently were found in oral malignant melanoma than in other tumors, and dMMR has relevance to MSI in both clinical cases and cell lines.

Potent adjuvant effect elicited for tumor immunotherapy by a liposome conjugated pH-sensitive polymer and dendritic cell-targeting Toll-like-receptor ligand

The generation of DCs with augmented functions is a strategy for obtaining satisfactory clinical outcomes in tumor immunotherapy. We developed a novel synthetic adjuvant comprising a liposome conjugated with a DC-targeting Toll-like-receptor ligand and a pH-sensitive polymer for augmenting cross-presentation. In an in vitro study using mouse DCs, these liposomes were selectively incorporated into DCs, significantly enhanced DC function and activated immune responses to present an epitope of the incorporated antigen on the major histocompatibility complex class I molecules. Immunization of mice with liposomes encapsulating a tumor antigen significantly enhanced antigen-specific cytotoxicity. In tumor-bearing mice, vaccination with liposomes encapsulating a tumor antigen elicited complete tumor remission. Furthermore, vaccination significantly enhanced cytotoxicity, targeting not only the vaccinated antigen but also the other antigens of the tumor cell. These results indicate that liposomes are an ideal adjuvant to develop DCs with considerably high potential to elicit antigen-specific immune responses; they are a promising tool for cancer therapy with neoantigen vaccination.

AB0648 COMPARING SYMPTOMS, TREATMENT PATTERNS, AND QUALITY OF LIFE OF ANKYLOSING SPONDYLITIS PATIENTS AND NON-RADIOGRAPHIC AXIAL SPONDYLOARTHRITIS IN JAPAN

Background:

Axial spondyloarthritis (axSpA) is a chronic inflammatory disease of the axial skeleton associated with impaired health-related quality of life (QoL) and disability.

Objectives:

To better understand the symptoms, clinical characteristics, treatment patterns, and quality of life (QoL), of non-radiographic axial spondyloarthritis (nr-axSpA) patients and how they compare to ankylosing spondylitis (AS) patients in Japan.

Methods:

Data from a cross-sectional survey conducted with physician (rheumatologists, orthopedic surgeon, and internal medicine) and their consulting patients in Japan were analyzed. Data were collected from Jun-Aug 2018 via physician-completed patient record forms and patient self-completed forms. Patients who had physician confirmed diagnoses of AS and nr-axSpA were eligible to participate. Demographics, disease status (improving, stable, unstable, deteriorating), symptoms, and medication use were reported by the physician, while work disability and QoL measures were reported by the patient using validated questionnaires. QoL and treatment patterns of nr-axSpA and AS patients were compared using parametric tests and non-parametric tests where appropriate.

Results:

Data from 41 physician, 72 AS patients, and 91 nr-axSpA patients were included in this analysis. A higher proportion of AS patients were male (70.8% vs. 58.2%; p=0.1040), yet this was not statistically significant. AS patients had a similar mean age (55.0 vs. 55.1; p=0.9762) compared to nr-axSpA patients. The majority of AS and nr-axSpA patients (61.1% vs. 62.9%; p=0.872) were not receiving a biologic. On average, AS and nr-axSpA patients reported similar rates of symptoms (Table 1). Patient reported outcomes such as the Assessment of SpondyloArthritis international Society Health Index (ASAS HI;6.0 vs. 6.4; p=0.6103), Patient Global Assessment (18.7 vs 22.7; p=0.4239), and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI; 3.1 vs. 3.4; p=0.3453) were similar between AS and nr-axSpA patients. AS patients reported a lower EQ-5D VAS (62.6 vs. 71.3; p=0.0237) when compared to nr-axSpA patients.

Table 1.

Characteristics of AS and nr-axSpA Patients in Japan

ASN=72Nr-axSpAN=91p-valueMean age, (SD)55.0 (17.5)55.1 (16.5)0.9762Gender, males; n (%)51 (70.8%)53 (58.2%)0.1040BMI, mean (SD)23.4 (3.5)22.7 (3.1)0.1890Joint Inflammation or Stiffness; n (%)25 (34.7%)32 (35.2%)1.0000Inflammatory Back Pain; n(%)25 (34.7%)34 (37.4%)0.7456HLA-B27 positive; n (%)7 (9.7%)4 (4.4%)0.2169Alternating Buttock Pain; n (%)6 (8.3%)5 (5.5%)0.5390Dactylitis; n (%)5 (6.9%)6 (6.6%)1.0000Enthesitis; n (%)5 (6.9%)9 (9.9%)0.5825Tendonitis; n (%)0 (0.0%)2 (2.2%)0.5037Synovitis; n (%)3 (4.2%)4 (4.4%)1.0000Arthritis; n (%)15 (20.8%)26 (28.6%)0.2806Osteoporosis; n (%)8 (11.1%)13 (14.3%)0.6412Physician’s Global VAS, mean (SD)12.1 (11.2)22.6 (11.0)0.0100Patient Global VAS, mean (SD)18.7 (18.5)22.7 (11.7)0.4239EQ-5D VAS, mean (SD)62.6 (25.0)71.3 (20.2)0.0237BASDAI, mean (SD)3.1 (1.8)3.4 (2.6)0.3453ASAS HI, mean (SD)6.0 (4.3)6.4 (5.1)0.6103

Conclusion:

Nr-axSpA and AS being part of the same disease spectrum (i.e. axial spondyloarthritis) share the same clinical features. The burden of the disease, as assessed by QoL measurements, is also similar in AS and nr-axSpA patients.

Figure 1.

Medication Use among AS and nr-axSpA Patients in Japan

Disclosure of Interests:

Tetsuya Tomita Consultant of: Eli Lilly and Company, Toshihiko Aranishi Employee of: Eli Lilly Japan, Kohei Hagimori Employee of: Eli Lilly Japan, Ko Nakajo Employee of: Eli Lilly Japan, Nicola Booth Consultant of: Janssen, Elizabeth Holdsworth Employee of: Adelphi Real World, Theresa Hunter Shareholder of: Eli Lilly and Company, Employee of: Eli Lilly and Company

Potential role of SC1, a cell adhesion molecule, in mammary gland tumors

SC1, an immunoglobulin superfamily cell adhesion molecule, is expressed in embryonic tissues and plays an important role in development through its cell adhesive activity. SC1 is also found in a variety of tumors and its expression is associated with a poor prognosis. The expressional patterns of SC1 were examined in sporadic cases of canine mammary gland tumors and it was found that this molecule is enriched in adenocarcinomas and is weaker in benign mixed tumors. SC1 might therefore be involved in the malignancy and progression of canine mammary gland tumors. To confirm this paradigm, the mammary gland cell line JYG-B was used as the recipient of SC1 cDNA. The resulting SC1-transfected cells were subsequently analyzed using a convenient in vitro model system. The self-aggregation activity of SC1-transfected cells was significantly increased and was blocked by an anti-SC1 antibody generated by hyper-immunized ostrich yolk. In addition, cell locomotion assays revealed an enhanced migration activity of SC1-transfected cells on SC1-coated transwell chambers. The in vivo activities of the cells were examined by subcutaneous implantation into nude mice. Tumor growth was significantly promoted in the mice after implantation with SC1-transfected cells, in comparison to parental- and mock-transfectants. This growth was inhibited by oral administration of gold-ion water. The invasion of SC1-transfectants into the surrounding muscular and adipose tissues was rigorously enhanced. These findings suggest that SC1 might promote the progression of mammary gland tumor cells by increasing cell adhesion.