Lymphoma consists of a subgroup of immunological cancers, which arise from malignant B and T lymphocytes. Comprising approximately 4% of cancers in the United States, lymphoma accounts for up to 19,940 deaths per year. Surgical biopsy is the primary method for lymphoma staging and diagnosis. Unfortunately, there are many risks associated with this procedure, including cosmetic disfigurement, seeding of malignant cells into previously unaffected tissue, and expense incurred by patients. Identification of unique cancer‐related biomarkers in urinary exosomes may provide a novel non‐invasive and cost‐effective tool for lymphoma diagnosis. Although analyses of biomarkers obtained from urinary exosomes have been used to evaluate urological cancers, these methods have not yet been translated to non‐urological pathologies, such as lymphomas. The objective for this study was to analyze the profile of microRNAs (miRNAs) obtained from urinary exosomes of mice bearing lymphoma tumors and compare it to miRNAs identified in urinary exosomes of tumor free (‐) control mice. Male and female C57BL/6 mice were injected with either 2.5x105 mouse EL‐4 lymphoma cells [tumor (+) mice, n=6] or phosphate‐buffered saline [tumor (‐) mice, n=6]. Tumor growth was monitored for up to 20 days with collection of serum, tumor tissues, and organs at the end of this period. Urine was collected for 48 hours beginning on day 17. Extraction of urinary exosomes was followed by total RNA isolation and RT‐qPCR using a set of PCR arrays consisting of 709 mouse‐specific miRNA primers. Fold changes in miRNA expression were quantified using the ∆∆Ct method. Mice developed tumors by day 13 with initial tumor appearance around day seven. There were no statistically significant differences between final tumor mass, body weights, or food and water intake in tumor (+) versus tumor (‐) mice. RT‐qPCR arrays of miRNAs extracted from urinary exosomes revealed 464 differentially expressed miRNAs between tumor (+) and tumor (‐) mice. Specifically, the expression of two miRNAs, significantly increased in urinary exosomes of tumor (+) mice compared to tumor (‐) mice, was also increased in the lymphoma tissue of origin. One miRNA with a significantly decreased expression in the urinary exosomes of tumor (+) mice was found to have a decreased expression in the lymphoma tissue of origin. Expression of miRNAs in mouse tissue was analyzed by RT‐qPCR. These results revealed that mice challenged with lymphoma tumors are releasing tumor‐specific miRNAs in their urine. These findings are in support of future clinical studies on the use of miRNA analysis in urinary exosomes for non‐invasive diagnostics of lymphoma patients.

Lymphoma accounts for approximately 4% of cancers in the United States, with an estimated 20,910 number of deaths per year. The standard method of diagnosis and staging of lymphoma involves surgical biopsy of the tumor - a procedure that has many negative associated risks. Exosomes are extracellular vesicles secreted in biological fluids that can serve as “liquid biomarkers”. Identification of unique cancer-related biomarkers in urinary exosomes may provide a novel non-invasive and cost-effective tool for lymphoma diagnosis. Analyses of biomarkers obtained from urinary exosomes have been used to evaluate urological cancers, however, these methods have not yet been translated to non-urological pathologies, such as lymphomas. The objective for this study was to determine the profile of microRNAs (miRNAs) expressed in urinary exosomes of mice challenged with lymphoma and compare it to miRNAs identified in urinary exosomes of control mice. Male and female C57BL/6 mice, (tumor (+), n=12), were injected with either 2.5x105 mouse EL-4 lymphoma cells or phosphate-buffered saline (tumor (-), n=12). Tumor growth was monitored for 20 days. Urine was collected for 48 hours starting on day 17 and serum, tumor tissues, and organs were collected on day 20. Extraction of urinary exosomes was followed by total RNA isolation and RT-qPCR for which a set of PCR arrays consisting of 709 mouse-specific miRNA primers was used. Fold changes in miRNA expression were quantified using the ΔΔCt method. Mice developed tumors by day 13 with initial tumor appearance around day seven. There were no statistically significant differences between final tumor mass, body weight, or food and water intake in tumor (+) versus tumor (-) mice. RT-qPCR arrays of miRNAs extracted from urinary exosomes revealed 464 miRNAs that were differentially expressed between tumor (+) and tumor (-). 215 miRNAs were up-regulated, while 249 miRNAs were down-regulated in tumor (+) mice. These results will be compared to miRNAs from serum and tumor tissues to identify tumor-specific miRNAs that can be used for potential application in the clinical setting. Citation Format: Brittany Wilson, Rebekah Betar, Alexander Martin, Zackaria Niazi, Michael Boyer, Lori Winter, Victor Babich, Francesca Di Sole, Elitsa Ananieva. microRNA expression profile in urinary exosomes is dependent on non-invasive lymphoma induction in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2377.

Enzymes in amino acid catabolism are emerging as attractive targets for cancer therapies. The mitochondrial branched-chain amino transferase (BCATm), an enzyme catalyzing the first step in leucine, valine, and isoleucine degradation, has been recently implicated in cancer growth but its role in T cell driven anti-cancer immunity has never been explored. To fulfill the gap in current scientific knowledge and address some of the challenges with lymphoma immunotherapies, we used the CD4-Cre-Lox recombination to create a conditional knockout mouse (T-BCATmKO) with CD4+ and CD8+ T cells deficient in the Bcat2 gene that encodes BCATm. Based on initial studies showing that a deletion of BCATm from T cells leads to increased glycolytic and oxygen metabolism and up-regulation of complex 1 of the mammalian target of rapamycin (mTORC1) signaling, we hypothesized that if BCATm is absent from T cells, this would stimulate T cell activation leading to improved T cell function in mice challenged with lymphoma. For this purpose, T-BCATmKO and T-BCATmfl/fl male mice (15-16 weeks old) were subcutaneously injected with 2.5x105 mouse lymphoma EG7-OVA cells. Tumor growth, animal weight, and food intake were recorded daily for a period of 20 days. Mice developed tumors around day 10 and this was not associated with weight loss or poor feeding of the mice as no changes in body weights or food intake between the different mouse groups were observed. Statistical analysis via one-way ANOVA revealed that T-BCATmKO mice had significantly delayed tumor growth compared to T-BCATmfl/fl mice (P= 0.05). In addition, CD4+ T cells isolated from T-BCATmKO mice released significantly more IFNγ after 48-72 hours of activation suggesting that CD4+ T cells from T-BCATmKO mice were more active than T cells from T-BCATmfl/fl mice. This study revealed that targeting BCATm in T cells may offer an advantage in mice to better fight lymphoma cancer and represents an attractive target for future immunotherapeutic anti-cancer approaches. Citation Format: Christie Adam, Alexander Martin, Rebekah Betar, Mercedes Foster, Michael Boyer, Elitsa Ananieva. T cell conditional knockout mouse model of the mitochondrial branched chain aminotransferase (BCATm) responds with delayed tumor growth to a lymphoma challenge [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1807.

The mitochondrial branched-chain aminotransferase (BCATm) catalyzes the transamination of leucine, an amino acid that is essential for the upregulation of complex 1 of the mammalian target of rapamycin (mTORC1) during T cell activation. Because BCATm is responsible for the mitochondrial degradation of leucine, we hypothesized that BCATm limits leucine availability for mTORC1 signaling and subsequently suppresses T cell activation. To test the hypothesis, we isolated CD4+T cells from the global BCATmKO mouse and measured the rates of leucine transamination/oxidation, the activity of the mTORC1 downstream targets S6 and 4EBP-1, and the release of IFNγ after 24–72h of T cell activation. To elucidate the role of BCATm in T cells in vivo, we used the Cre-LoxP strategy to create a T cell specific deletion of BCATm in C57BL/6 mice. We completed the initial characterization of the mice, which included a validation of absence of BCATm in T cells by using qRT-PCR and Western blotting. Results demonstrated that BCATm-deficient T cells experienced significant reductions in the transamination and oxidation of leucine, which led to increased intracellular leucine concentrations. This correlated with an increased phosphorylation of S6, but not 4EBP-1, suggesting that BCATm regulates mTORC1 signaling in S6 dependent manner. The T cells released more IFNγ in the absence of BCATm, which was highest after 72h of T cell activation. Thus, BCATm appears to play an immunosuppressive role by reducing CD4+ T cell activation. The newly designed T cell conditional BCATmKO mice, which do not express BCATm in CD4+ and CD8+ T cells will be engaged in preclinical studies aiming at deciphering the therapeutic potential of BCATm in T cell-driven immunological responses.

Primary bone and joint cancers are rare and understudied, yet these neoplasms are difficult to treat and impact all age groups. To explore the long-term changes in the occurrence of bone and joint cancers, patients diagnosed with these neoplasms between 1975 and 2016 were identified in the Surveillance Epidemiology and End Results of the National Cancer Institute of the USA. The age-adjusted incidence (AAIR) and mortality (AAMR) rates were calculated for three decades and compared to AAIR and AAMR in years 1975–1984. By using the population-based cancer registries of the USA, Iowa was identified as a state with increased cases of bone and joint malignancies. The bone and joint cancer cases in Iowa were correlated with the percentage of rural population, the average farmland size, or the residential radon levels. Results demonstrated that the mean AAIR of bone and joint cancers for US female and male patients (< 50 years of age) increased from 0.57 (95% C.I. 0.55–0.63) and 0.76 (95% C.I. 0.69–0.82) for years 1975–1984 to 0.71 (95% C.I. 0.66–0.76) and 0.94 (95% C.I. 0.87–1.07) for years 2005–2014, respectively. The increase in bone and joint cancer cases in Iowa positively correlated with the percentage rural population ( R = 0.222, P < 0.02), and the average farmland size ( R = 0.236, P < 0.02) but not the radon levels ( R = − 0.038, P < 0.7). The findings revealed that patients younger than 50 years of age and those who resided in rural areas and engaged in farming were more likely to be diagnosed with primary bone and joint cancers. Supplementary Information The online version contains supplementary material available at 10.1007/s10653-022-01261-5.