Kinase activity profiling in renal cell carcinoma, benign renal tissue and in response to four different tyrosine kinase inhibitors

Kinase activity is frequently altered in renal cell carcinoma (RCC), and tyrosine kinase inhibitors (TKIs) are part of the standard treatment strategy in patients with metastatic disease. However, there are still no established biomarkers to predict clinical benefits of a specific TKI. Here, we performed protein tyrosine kinase (PTK) profiling using PamChip^® technology. The aim of this study was to identify differences in PTK activity between normal and malignant kidney tissue obtained from the same patient, and to investigate the inhibitory effects of TKIs frequently used in the clinics: sunitinib, pazopanib, cabozantinib and tivozanib. Briefly, our results showed that 36 kinase substrates differs (FDR < 0.05) between normal and cancer kidney tissue, where members of the Src family kinases and the phosphoinositide-3-kinase (PI3K) pathway exhibit high activity in renal cancer. Furthermore, ex vivo treatment of clear cell RCC with TKIs revealed that pathways such as Rap1, Ras and PI3K pathways were strongly inhibited, whereas the neurotrophin pathway had increased activity upon TKI addition. In our assay, tivozanib and cabozantinib exhibited greater inhibitory effects on PTK activity compared to sunitinib and pazopanib, implying they might be better suitable as TKIs for selected RCC patients.

Abstract 2292: Tyrosine kinome profiling of renal cell carcinoma (RCC)

Background: Tyrosine kinase inhibitors (TKIs) constitute the backbone of treatment of metastatic (m) RCC. TKIs show great inter-individual variability of both efficacy and toxicity. The aim of this study was to compare the tyrosine kinase activity in normal and malignant kidney tissue and explore TKI effect on tumor tissue ex vivo.

Materials and methods: Human nephrectomy samples (n = 295) consecutively collected at Akershus University Hospital from 2013 to 2019 were available. For this study, 22 samples of patients with mRCC (twenty-one clear cell and one chromophobe histology) and 3 with non-metastatic disease (two clear cell and one papillary histology) were selected. Tumor and normal tissue from each patient were prepared and assessed by an experienced pathologist, and 5µg of protein lysates was extracted. Kinase activity profiling of 144 tyrosine kinase peptides was performed using PamChip Arrays for PAMSTATION12. Protein lysates from tumors were in addition treated with four different TKIs ex vivo, based on IC50; sunitinib (2.5 µM), cabozantinib (2.5 µM), pazopanib (10 µM) and tivozanib (2 µM). All data was processed and analyzed in Bionavigator V.6 (PamGene).

Results: The overall tyrosine kinase activity was increased in tumor tissue compared to normal tissue in all samples. The activity of 36 tyrosine kinases differed significantly (FDR &lt; 0.05), with 20 kinases showing higher and 16 showing lower phosphorylation in tumor compared to normal tissue. Furthermore, adding TKIs to tumor samples ex vivo revealed different potencies of the TKIs. Tivozanib and cabozantinib showed higher inhibition potency compared to sunitinib and pazopanib. Two well-defined peptide clusters were especially affected by tivozanib and cabozantinib exposure. Compared to untreated tumor tissue, the activity of 29 kinases including common TKI targets MET, EGFR, PDGFR and FGFR was significantly reduced in cluster 1. However, we also identified reduced activity of several other kinases i.e. RB, CDK2, CLB, CAM, ZAP70 and PDK1 involved in RAS, RAP1, PI3K-AKT and prostate cancer signaling pathways. In cluster 2, 21 kinases showed increased activity upon TKI exposure, amongst them JNK, ERK, erbB1/erbB2, Shp2 and PLCγ involved in MAPK, ERBB and proteoglycans signaling pathways, and possibly accounting for subsequent TKI resistance.

Conclusion: Kinase activity differs significantly between malignant and normal kidney tissue. Furthermore, we have demonstrated different inhibitory effects of TKIs ex-vivo and identified two peptide clusters significantly affected by TKI. Further analysis of affected kinases and signaling pathways as well as correlations with clinical data for the same group of patients will be performed. To our knowledge, similar systematic comprehensive analysis of tyrosine kinase activity and correlation to clinical data has not been reported previously.

Citation Format: Katarina Puco, Andliena Tahiri, Faris Naji, Daniel Heinrich, Vessela N. Kristenssen, Glenny C. Alfsen, Lorant Farkas, Frode S. Nilsen, Stig Müller, Jan Oldenburg, Jürgen Geisler. Tyrosine kinome profiling of renal cell carcinoma (RCC) [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 2292.

Abstract 481: Utility of hCG as a biomarker of treatment response in advanced urothelial cancer: A population based series at Akershus University Hospital, Norway

Background

Treatment options in patients with advanced urothelial carcinoma (aUC) have improved significantly in the last decade, highlighting the need for adequate biomarkers. High tumor CGB5 mRNA, encoding Human Chorionic Gonadotrophin β (hCGβ) and elevated serum free hCGβ are related to poorly differentiated UC and correlated to poor prognosis. Hypothetically, hCG could be used as serum tumor marker in aUC patients.

Patients and methods

From December 2018 to November 2020, serum hCG levels were measured in 62 aUC patients referred to the oncology department, Akershus University Hospital. Median age 68 years, 42 male and 21 female. Total serum hCG (intact hCG + free hCGβ) was measured by electrochemiluminescence immunoassay “ECLIA”. In order to compensate for hypogonadism-related increases, hCG ≥ 50% above upper normal limit was considered as being elevated (hCG+), otherwise it was considered negative (hCG-). Further, hCG levels were defined as increasing (↑) or declining (↓) at treatment evaluation and follow up. Radiologically, patients had newly diagnosed disease (ND), progressive disease (PD) or non-PD (stable disease, partial or complete response) according to RECIST 1.1 at evaluation and follow up. hCG values were correlated with radiological findings at diagnosis, during and after treatment. Statistics by 2 x 2 contingency table and Chi Square (χ2) test.

Results

At least one hCG+ value was measured in 38 of 62 patients (61%), range 0.8 - 62,700 IU/L, and hCG was elevated in 22 of 43 patients (51%) with available hCG value at diagnosis, mean 15 IU/L (range 0.8 - 58). In total 213 hCG measurements could be correlated with concomitant CT or MR scans. At radiologic evaluation of ND & PD, hCG+/↑ and hCG -/↓ was found in 62 and 50 measurements, respectively. At non-PD, hCG -/↓ and hCG+/↑ was found in 94 and 7 measurements, respectively. For ND & PD versus non-PD, hCG showed a sensitivity and specificity of 55% and 93% respectively (95% CI 46-65% and 86-97%), positive and negative predictive value of 90% and 65% (95% CI 81-95% and 60-70%) and accuracy of 73% (95% CI 66-79%), χ2: p&lt;0.00001. Exclusion of the 24 patients without elevated hCG showed improved sensitivity 76% at the cost of lower specificity 82% (95% CI 65-85% and 66-92% respectively), positive and negative predictive value 90% and 63% (95% CI 82-95% and 52-72%) and accuracy of 78% (95% CI 70-86%), χ2: p&lt;0.00001.

Conclusions

Ectopic hCG production was observed in 61% of aUC patients with a strong and meaningful correlation between hCG changes and radiologic evaluation of treatment response. Intriguingly, hCG increase sometimes preceded radiologic PD, thus categorized as “false positive” until subsequent radiologic PD. hCG appears to be a promising tumor marker for biochemical treatment response evaluation in aUC patients.

Citation Format: Katarina Puco, Johan Bjerner, Stig Müller, Gunder M. Lilleaasen, Haldor Husby, Mattias Røed-Undlien, Daniel Heinrich, Fredrik A. Dahl, Oluf D. Røe, Jan Oldenburg. Utility of hCG as a biomarker of treatment response in advanced urothelial cancer: A population based series at Akershus University Hospital, Norway [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 481.