Renca Cells Research Articles

The identification of a novel orally available ferroptosis inducer for the treatment of clear cell renal carcinoma

Abstract Background Background: Clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer, is typically initiated by inactivation of the von Hippel Lindau (VHL) gene resulting in constitutive activation of the hypoxia inducible factors, HIF-1α and HIF-2α. HIF-2α is a central driver of kidney cancer progression and is a well validated therapeutic target for ccRCC. Additionally, VHL loss and HIF activation promote lipid accumulation that increases the sensitivity of ccRCC cells to ferroptosis, a form of cell death characterized by iron dependent lipid peroxidation. However, classical inducers of ferroptosis, which induce ferroptosis in vitro, show limited activity in vivo due to possible redundancies in the extracellular space, suggesting a need for novel molecular targets for the induction of ferroptosis in vivo for therapeutic benefit. Methods Method: We performed a high-throughput screen to identify small molecule inhibitors of HIF-2α and performed additional validation and structure activity relationship studies to identify compounds with improved potency of HIF-2α inhibition. The molecular target of these inhibitors was determined by mass spectrometry using the Drug Affinity Responsive Target Stability (DARTS) assay, and target validation was confirmed using siRNA knockdown and NMR. In vivo anti-tumor efficacy was verified using syngeneic RENCA cells injected into Balb/C mice. Exposure to KD061 was verified using LC-MS/MS detection of KD061 in the plasma and tumors of treated mice. Results Results: We identified a novel molecule, KD061, which decreases levels of HIF-1/2α and induces ferroptosis in vivo through oral administration by targeting Iron Sulfur Cluster Assembly 2 (ISCA2). ISCA2 is a component of the late mitochondrial Iron Sulfur Cluster (L-ISC) assembly complex and ISCA2 inhibition either pharmacologically or using siRNA triggers the iron starvation response, resulting in iron/metals overload and death via ferroptosis. Cell death induced by KD061 was decreased by re-expression of VHL, suggesting synthetic lethality in the context of VHL loss. ISCA2 inhibition also decreased HIF-2α protein levels by blocking iron-responsive element (IRE)-dependent translation, and at higher concentrations, also decreased HIF-1α translation through unknown mechanisms. Treatment of tumor-bearing RENCA-Balb/C mice with KD061 significantly reduced tumor growth in vivo, decreased HIF-α levels and increased lipid peroxidation, suggesting increased ferroptosis in vivo. Treatment with KD061 was well tolerated at the therapeutic dose with no detectable effects on blood chemistry and blood counts. Conclusions Conclusions: Here, we describe the first orally available inducer of ferroptosis with anti-tumor efficacy in vivo. The targeting of ISCA2 using KD061 is a promising therapeutic strategy to inhibit HIF-1/2α and to induce ferroptosis in pVHL deficient cells. CDMRP DOD Funding: yes

Synergistic anti-tumour activity of sorafenib in combination with pegylated resveratrol is mediated by Akt/mTOR/p70S6k-4EBP-1 and c-Raf7MEK/ERK signaling pathways

IntroductionTo investigate the inhibitory effect of sorafenib combined with PEGylated resveratrol on renal cell carcinoma (RCC) and its potential mechanism. MethodsMTT assay was used to detect the inhibitory effects of PEGylated resveratrol and sorafenib alone or combination on proliferation of RCC cells. Scratch and transwell assays were performed to examine the effects on the in vitro migration and invasion of RCC cells, respectively. The anti-tumor activity as well as splenic lymphocyte proliferation of the combination therapy was evaluated in the RCC xenograft mouse model. Western blotting method was used to detect changes in proteins involved in the antitumor efficacy related signaling pathways. ResultsInhibitory effects of PEGylated resveratrol combined with sorafenib incubation on the proliferation of Renca cells was synergistically enhanced compared with the mono-incubation group (both P < 0.01, CI < 1). Scratch and transwell assays revealed that combined incubation could significantly inhibit the migration and invasion of 786-O cells in vitro. Combined PEGylated resveratrol with sorafenib could significantly inhibit the growth of Renca renal carcinoma in mice with the tumor growth inhibition (TGI) of 85.5% and one achieved complete remission on D14, while the two monotherapies were both below 43% on D14, suggesting that current combination may have synergistic anti-renal carcinoma activity. Compared with the control group, PEGylated resveratrol combined with sorafenib in vivo promoted the proliferation of unactivated splenic lymphocytes and the proliferation of lymphocytes stimulated with concanavalin A and lipopolysaccharide. Western blotting results showed that combination therapy may suppress the growth of renal cell carcinoma by inhibiting AKT/mTOR/p70S6k-4EBP-1 and c-Raf7MEK/ERK signaling pathways. ConclusionPEGylated resveratrol combined with sorafenib can achieve synergistic anti-RCC activity, and the mechanism may be related to the inhibition of Akt/mTOR/p70S6k-4EBP-1 and c-Raf7MEK/ERK signaling pathways.

Comparative analysis of the effect of hypoxia in two different tumor cell models shows the differential involvement of PTEN control of proangiogenic pathways.

Hypoxia, low, non-physiological oxygen tension is a key regulator of tumor microenvironment, determining the pathological tumor vascularization. Alleviation of hypoxia through vessel normalization may be a promising therapeutic approach. We aimed to assess the role of low oxygen tension in PTEN-related pathways and proangiogenic response, in vitro, in two different tumor cell lines, focusing on potential therapeutic targets for tumor vessel normalization. Downregulation of PTEN in hypoxia mediates the activation of distinct mechanisms: cytoplasmic pAKT activation in melanoma and pMDM2 modulation in kidney cancer. We show that hypoxia-inducedproangiogenic potential was stronger in Renca cells than B16 F10-confirmed by a distinct secretory potential and different ability to affect endothelial cells functions. Therefore, the impact of hypoxia on PTEN-mediated regulation may determine the therapeutic targets and effectiveness of vessel normalization and intrinsic characteristics of cancer cell have to be taken into account when designing treatment.

Assessments of therapeutic effects according to timings for combined therapy with axitinib and immune check point inhibitor in a mouse renal cell carcinoma model

Recently, several types of systemic therapy using tyrosine kinase inhibitor (TKI) and immune checkpoint inhibitor (ICI) have been performed for advanced renal cell carcinoma (aRCC) patients; however, the optimal strategy of sequential treatment with these agents has not been well established. The objective of this study was to determine the differences of therapeutic effects according to timing for the introduction of TKI and ICI using a mouse RCC, RenCa model. The effects of combined treatment of TKI and/or ICI with axitinib, anti-mouse programmed death (PD)-1, or PD-ligand 1 (PD-L1) antibody on tumor growth and survival after subcutaneous and intravenous injection of RenCa cells, respectively, were compared according to three different treatment schedules: simultaneous administration, initial axitinib administration, and initial ICI administration. Infiltrating patterns of lymphocytes into tumors after combined treatments were evaluated by immunohistochemical staining. In mice treated with anti-PD-1 and anti-PD-L1 antibodies, significantly marked inhibitory effects on subcutaneous growth of tumors were observed in the simultaneous and initial ICI treatment groups, but not the group with the initial axitinib administration, compared to controls without treatment. Survival intervals of mice after intravenous injection of RenCa cells were significantly longer in the simultaneous and initial ICI administration, but not the initial axitinib administration, compared to the control. Furthermore, both CD8+ to CD3+ and CD8+ to CD11b+ T-lymphocyte ratios in subcutaneous RenCa tumors were significantly higher in the simultaneous and initial ICI administration, but not the initial axitinib administration, compared to the control. Favorable control against aRCC progression may be achieved by administering TKI and ICI simultaneously or ICI followed by TKI.

A cisplatin conjugate with tumor cell specificity exhibits antitumor effects in renal cancer models

BackgroundClear cell renal cell carcinoma (ccRCC) is the most common type of kidney cancer and is notorious for its resistance to both chemotherapy and small-molecule inhibitor targeted therapies. Subcellular targeted cancer therapy may thwart the resistance to produce a substantial effect.MethodsWe tested whether the resistance can be circumvented by subcellular targeted cancer therapy with DZ-CIS, which is a chemical conjugate of the tumor-cell specific heptamethine carbocyanine dye (HMCD) with cisplatin (CIS), a chemotherapeutic drug with limited use in ccRCC treatment because of frequent renal toxicity.ResultsDZ-CIS displayed cytocidal effects on Caki-1, 786-O, ACHN, and SN12C human ccRCC cell lines and mouse Renca cells in a dose-dependent manner and inhibited ACHN and Renca tumor formation in experimental mouse models. Noticeably, in tumor-bearing mice, repeated DZ-CIS use did not cause renal toxicity, in contrast to the CIS-treated control animals. In ccRCC tumors, DZ-CIS treatment inhibited proliferation markers but induced cell death marker levels. In addition, DZ-CIS at half maximal inhibitory concentration (IC50) sensitized Caki-1 cells to small-molecule mTOR inhibitors. Mechanistically, DZ-CIS selectively accumulated in ccRCC cells’ subcellular organelles, where it damages the structure and function of mitochondria, leading to cytochrome C release, caspase activation, and apoptotic cancer cell death.ConclusionsResults from this study strongly suggest DZ-CIS be tested as a safe and effective subcellular targeted cancer therapy.

Abstract 49: Comparison of subcutaneous and orthotopic tumor growth in syngeneic mouse models of ovarian and renal cancer

Abstract Oncology drug development has markedly lower success rate (3.4%) than other indications (20.9%) as reported by Wong, Siah and Lo in 2019. Animal models are often pointed at as the culprits for failure in clinical trials. While better animal models for cancer are needed and constantly developed, the incentive of drug developers to use those might not be clear, because the regulatory authorities do not require it. Subcutaneous tumors have earned their place in drug development but adding more sophisticated models to the testing panel before entering the clinical phase should improve the success rate. We present here the properties of subcutaneous and orthotopic tumor growth in two syngeneic models. HM-1 murine ovarian cancer cells were inoculated subcutaneously (s.c.) and intraperitoneally (representing the stage of intraperitoneal carcinomatosis) and murine renal adenocarcinoma Renca cells s.c. and orthotopically within the renal capsule. Body weight and tumor growth were followed, and mice were sacrificed according to humane endpoint criteria. To compare tumor growth in s.c. sites and within the abdomen, the tumor weight at sacrifice was divided by the number of days since the inoculation. In the HM-1 model, the mice with intraperitoneal tumor were sacrificed due to build-up of ascites on average six days earlier that the mice with s.c. tumor. In s.c. HM-1 tumor-bearing mice, the reason for sacrifice was tumor ulceration. In the Renca model, the s.c. and intrabursal models were approximately the same length. There was a striking difference in the tumor growth rate (mg/day) in s.c. versus abdominal sites in both models. The growth was 4-5 times faster in the abdominal sites than subcutaneously, highlighting the effect of tumor specific microenvironment. It is easy to understand that having promising results might be easier in a slower growing model. However, since both ovarian and renal cancer show very different growth kinetics within the abdominal cavity, testing drug candidates aimed for those indications in orthotopic models before accessing the clinical trials could give a more relevant evaluation of the potency of the drug candidates. Citation Format: Mari I. Suominen, Justyna Zdrojewska, Yvonne Konkol, Katja M. Fagerlund, Mervi Ristola, Jukka P. Rissanen. Comparison of subcutaneous and orthotopic tumor growth in syngeneic mouse models of ovarian and renal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 49.

Total Flavone Content of Cydonia oblonga Miller Inhibits Proliferation and Migration of Renal Carcinoma Cells by Inhibiting the S1PR2/FAK Pathway

Cydonia oblonga Miller (C. oblonga) is known for its beneficial properties for health since ancient times. C. oblonga has also been shown to possess antihemolytic, antidiabetic, and antilipoperoxidation, as well as lipid-lowering properties. Modern research has shown that C. oblonga also possess antitumor effects. However, studies have not reported whether its main compounds inhibit renal cell carcinoma (RCC) development and progression. We found the inhibitory effect of total flavone of C. oblonga (TFCOM) in RCC cells through in vitro screening tests. The molecular mechanism of this effect is still unknown. Therefore, molecular docking combined with network pharmacological methods was used in order to clarify the molecular mechanisms of TFCOM anticancer effects. TFCOM showed potent inhibitory effects on the proliferation and migration of 786-O and Renca cells. Hoechst 33342 staining test results indicated that TFCOM’s cell growth inhibition in RCC cells may be mediated through apoptosis. It may significantly influence S1PR2/FAK, WNT/β-catenin, and PI3K/AKT/mTOR signaling pathways that can regulate a series of cellular activities and can participate in the processes of cell proliferation, migration, and apoptosis. We conclude that TFCOM has antitumor activity against kidney cancer. It may induce apoptosis and inhibitory effects on cell proliferation and migration through S1PR2/FAK, WNT/β-catenin, and PI3K/AKT/mTOR signal pathways. TFCOM might be a potential anticancer drug to be further developed for human kidney cancer therapy. In recent years, many synthetic drugs with anticancer effects have the disadvantages of high price and side effects. Thus, the development of anticancer drugs from natural resources has its application value. Our results suggest that TFCOM, as a natural product, has multiple target effects, and it may act through proteins and receptors such as FAK and S1PR2, thereby affecting the activation of downstream proteins and inhibiting the occurrence and development of renal cancer cells.

Artificial Diets with Altered Levels of Sulfur Amino Acids Induce Anticancer Activity in Mice with Metastatic Colon Cancer, Ovarian Cancer and Renal Cell Carcinoma.

Sulfur-containing amino acids methionine (Met), cysteine (Cys) and taurine (Tau) are common dietary constituents with important cellular roles. Met restriction is already known to exert in vivo anticancer activity. However, since Met is a precursor of Cys and Cys produces Tau, the role of Cys and Tau in the anticancer activity of Met-restricted diets is poorly understood. In this work, we screened the in vivo anticancer activity of several Met-deficient artificial diets supplemented with Cys, Tau or both. Diet B1 (6% casein, 2.5% leucine, 0.2% Cys and 1% lipids) and diet B2B (6% casein, 5% glutamine, 2.5% leucine, 0.2% Tau and 1% lipids) showed the highest activity and were selected for further studies. Both diets induced marked anticancer activity in two animal models of metastatic colon cancer, which were established by injecting CT26.WT murine colon cancer cells in the tail vein or peritoneum of immunocompetent BALB/cAnNRj mice. Diets B1 and B2B also increased survival of mice with disseminated ovarian cancer (intraperitoneal ID8 Tp53-/- cells in C57BL/6JRj mice) and renal cell carcinoma (intraperitoneal Renca cells in BALB/cAnNRj mice). The high activity of diet B1 in mice with metastatic colon cancer may be useful in colon cancer therapy.

Biogenesis of Mesoporous Silica Nanoparticles Enclosed in Extracellular Vesicles by Mouse Renal Adenocarcinoma Cells.

Integrating the versatility of synthetic nanoparticles to natural biomaterials, such as cells or cell membranes, has gained considerable attention as promising alternative cargo delivery platforms in recent years. Extracellular vesicles (EVs), natural nanomaterials composed of a protein-rich lipid bilayer secreted by cells, have also shown advantages and great potential as a nano delivery platform in combination with synthetic particles due to their specific natural properties in overcoming several biology hurdles possessed in the recipient cell. Therefore, the preservation of EV's origin properties is critical for their application as nanocarriers. This chapter will describe the encapsulation procedure of MSN encapsulated in EV membrane derived from mouse renal adenocarcinoma (Renca) cells through biogenesis. The FMSN-enclosed EVs produced through this approach still contain preserved EV's natural membrane properties.

Manipulation of Amino Acid Levels with Artificial Diets Induces a Marked Anticancer Activity in Mice with Renal Cell Carcinoma.

Targeted therapies with antiangiogenic drugs (e.g., sunitinib) and immune checkpoint inhibitors (e.g., anti-PD-1 antibodies) are the standard of care for patients with metastatic renal cell carcinoma. Although these treatments improve patient survival, they are rarely curative. We previously hypothesized that advanced cancers might be treated without drugs by using artificial diets in which the levels of specific amino acids (AAs) are manipulated. In this work, after showing that AA manipulation induces selective anticancer activity in renal cell carcinoma cells in vitro, we screened 18 artificial diets for anticancer activity in a challenging animal model of renal cell carcinoma. The model was established by injecting murine renal cell carcinoma (Renca) cells into the peritoneum of immunocompetent BALB/cAnNRj mice. Mice survival was markedly improved when their normal diet was replaced with our artificial diets. Mice fed a diet lacking six AAs (diet T2) lived longer than mice treated with sunitinib or anti-PD-1 immunotherapy; several animals lived very long or were cured. Controlling the levels of several AAs (e.g., cysteine, methionine, and leucine) and lipids was important for the anticancer activity of the diets. Additional studies are needed to further evaluate the therapeutic potential and mechanism of action of this simple and inexpensive anticancer strategy.

Tumoral Endoglin (CD105) Regulates the Tumor Microenvironment, Tumorigenicity and Therapeutic Response in Renal Cell Carcinoma

<h3>Purpose/Objective(s)</h3> Endoglin (CD105) is a transmembrane glycoprotein that serves as a co-receptor for the TGF-β signaling cascade. Due to its elevated expression on tumor associated vasculature of highly vascular cancers, it is categorized as a tumor associated antigen (TAA). Although CD105 has been largely studied as an endothelial cell marker and mediator of angiogenesis in various cancers including Renal cell carcinoma (RCC), the effect of its expression by tumor cells has not been fully elucidated in immune-competent models. Here we address the implication of tumoral CD105 on the tumor microenvironment (TME) and response to a <i>Listeria-monocytogenes</i> based immunotherapeutic vaccine directed against CD105 based on the hypothesis that "<i>Tumoral CD105 contributes to the aggressive phenotype of RCC and further drives response to immunotherapy"</i>. <h3>Materials/Methods</h3> A mutant version of Renca that is deficient in CD105(CD105KO-Renca) was generated from murine Renca cell line using CRISPR/cas9. In an immunocompetent model syngeneic to male BALB/C mice, subcutaneously implanted control Renca (Scr-Renca) or CD105 KO-Renca tumors were monitored for tumor growth. Tumor tissues from either group were subjected to flow cytometry and gene expression using RT-qPCR. The contribution of tumoral CD105 to neovascularization was determined by matrigel plug angiogenesis assay followed by hemoglobin quantification. Lastly, we elucidated how tumoral expression of CD105 affects the response to a <i>Listeria-</i>based vaccine directed against CD105 (Lm-LLO-CD105) in a subcutaneous immunocompetent mouse model. <h3>Results</h3> CD105KO-Renca displays increased potential for early tumor formation, but the tumor progression is reduced compared to the Scr-Renca. Deletion of tumoral CD105 impacted the TME by increasing the population of multicytokine (IFNγ⁺ IL-2⁺TNFα⁺) producing CD8⁺ and CD4⁺ T cells and reducing infiltration of myeloid derived suppressor cells (MDSCs) and M2-macrophages. Further, tumoral CD105 contributes to angiogenesis as observed by a reduction in the hemoglobin content and CD31mRNA and VEGFa mRNA in Renca-CD105KO tumor tissues. Finally, Lm-LLO-CD105 was able to control tumor growth in the Scr-Renca tumor bearing mice but not in the CD105KO-Renca tumor bearing mice. Lm-LLO-CD105 increases the CD8⁺ T cell infiltration, production of cytokines and reduces the population of CD4⁺Foxp3⁺Tregs in the TME of Scr-Renca but not in the CD105-KO-Renca tumors. <h3>Conclusion</h3> Tumoral CD105 serves as an independent prognostic that is important for both tumor progression and modulation of the RCC's immunological phenotype. Furthermore, CD105 deficient RCC did not respond to an immunotherapeutic strategy that is dependent on CD8⁺ T cell recruitment. Altogether, our data suggests that tumoral CD105 is an important mediator of tumor progression and response to immunotherapy.

Compound C Inhibits Renca Renal Epithelial Carcinoma Growth in Syngeneic Mouse Models by Blocking Cell Cycle Progression, Adhesion and Invasion

Compound C (CompC), an inhibitor of AMP-activated protein kinase, reduces the viability of various renal carcinoma cells. The molecular mechanism underlying anti-proliferative effect was investigated by flow cytometry and western blot analysis in Renca cells. Its effect on the growth of Renca xenografts was also examined in a syngeneic BALB/c mouse model. Subsequent results demonstrated that CompC reduced platelet-derived growth factor receptor signaling pathways and increased ERK1/2 activation as well as reactive oxygen species (ROS) production. CompC also increased the level of active Wee1 tyrosine kinase (P-Ser642-Wee1) and the inactive form of Cdk1 (P-Tyr15-Cdk1) while reducing the level of active histone H3 (P-Ser10-H3). ROS-dependent ERK1/2 activation and sequential alterations in Wee1, Cdk1, and histone H3 might be responsible for the CompC-induced G2/M cell cycle arrest and cell viability reduction. In addition, CompC reduced the adhesion, migration, and invasion of Renca cells in the in vitro cell systems, and growth of Renca xenografts in the BALB/c mouse model. Taken together, the inhibition of in vivo tumor growth by CompC may be attributed to the blockage of cell cycle progression, adhesion, migration, and invasion of tumor cells. These findings suggest the therapeutic potential of CompC against tumor development and progression.

EFFECT OF THYMOQUINONE IN COMBINATION WITH NIVOLUMAB ON EXPERIMENTAL RENAL CELL CANCER MODELS

Objectives: Thymoquinone a bioactive component extracted from the seeds of Nigella sativa, has been proved to have antiinflammatory, antioxidant properties anti antitumor efficiency against breast, prostate, bladder, and renal cell cancer. We aimed to investigate the synergistic cytotoxic and apoptotic effects of thymoquinone in combination with nivolumab, an immuno-control inhibitor, and its mechanism in renal cell cancer models. Materials and Methods: In vitro studies: Caki-1 and Renca renal cancer cell lines with mononuclear cells were cocultured and thymoquinone and nivolumab effect were analyzed by MTT and Annexin V + PI. In vivo studies: Renal cell cancer model was provided by subcutaneous injection of RENCA cells to C57BL/6, male, 8 weeks old mice in four groups. Control group, thymoquinone (1,4,7,14days,20mg/kgIP), nivolumab administered (1,6,13days10mg/ kgIP), thymoquinone and nivolumab. Seven animals was randomized in each experimental group. Apoptosis, necrosis, CD4,CD8,C20,CD34,CD31,VEGF-A by immunohistochemistry, FGFR-1,PDGFRbeta,VEGFR-2,c-kit,RET,c-Met,AXL,Flt-3,TIE2, ICAM-1,VCAM-1 and E-selectin mRNA levels by quantitative real-timePCR were evaluated on tumor tissue. Liver, kidney, brain, lung and heart tissues was evaluated for side effects. Plasma biochemistry tests were performed. Statistical analysis was be performed with Mann-Whitney U test with p &lt;0.05 value. Results: Thymoquinone showed antitumor effect in vitro and in vivo. It also showed increase in immune cell death of nivolumab. Tumor tissue showed prominent necrosis or complete response to therapy in combination group. Conclusions: We conclude that thymoquinone has antitumor effect on renal cell carcinoma and increases the effect of nivolumab immune, cell death effects. Besides, it does not have side effect on other organs whether alone or in combination.&nbsp;

Abstract 3293: In vitro cellular and molecular effects of oncolytic vaccinia virus in clear and non-clear cell renal cell carcinoma

Abstract Oncolytic vaccinia virus has several advantages over other OV platforms, including an efficient life cycle, multiple mechanisms of viral spread, large genome, allowing acceptance of foreign therapeutic DNA inserts, and proven safety in humans, due to its use as smallpox vaccine. JX-594 (Pexavec, SillaJen) is an attenuated (TKdeactivated ) oncolytic vaccinia VV, engineered to express GM-CSF and to selectively target tumor over non-tumor tissues. It is currently being investigated as a novel therapeutic option in patients with advanced Renal Cell Carcinoma (RCC, NCT03294083). The present study was undertaken to investigate the effects of JX-954 in a panel of clear and non-clear cell RCC cell lines and characterize the potential mechanisms of JX-594 oncolysis in vitro. We evaluated the oncolytic potency of JX-594 in human clear cell RCCs (VHL mutant 786-0, A498, VHL wild type Caki-1), non-clear cell RCC (ACHN, papillary RCC, and UOK-262, an FH deficient papillary RCC cell) and murine renal cancer cells (RENCA). Potent and persistent cytotoxic effects were induced by JX-594 in all human RCC cells, regardless of the histological subtype, and by mJX-594 (a Western Reserve strain of vaccinia virus expressing murine GMCSF) in RENCA cells. Moreover, we observed efficient viral replication in human (786-0, ACHN) and murine (RENCA) cells, confirming RCC permissiveness to viral infection. Functional proteomics analysis of JX-594 treated 786-0 cells was performed by reverse phase protein array (RPPA) to gain knowledge on potential mechanisms of viral oncolysis. JX-594 treatment had significant effects on the expression levels of proteins related to inducing cell cycle, apoptosis, necrosis, Akt signaling, MAPK signaling, autophagy and stress induction. In particular, the proteins related to cell cycle (Wee1, Cdc25c, CHK1/2, and Cyclin B1) and Akt signaling (PI3K, mTOR, Rictor and FOXO), MAPK signaling (JAK2, PAK1, FAK and MEK1) were down regulated, while proteins involved in apoptosis and necrosis were upregulated. In summary, our studies show that human and murine renal cancer cells are permissive to infection and replication by JX-594 and mJX-594, which induce potent oncolytic effects in clear and non-clear cell RCC, effects associated with significant modulation of RCC pathways associated with cell cycle, proliferation, and survival and stress responses. Citation Format: Yuqi Jing, F Bustamante Guerrero, Jaime Merchan. In vitro cellular and molecular effects of oncolytic vaccinia virus in clear and non-clear cell renal cell carcinoma [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 3293.

Abstract 3725: SETD2 loss in renal carcinoma cells induces the unfolded protein response

Abstract Introduction: SETD2 encodes a histone H3-K36 methyltransferase which is frequently inactivated in clear cell renal carcinomas (ccRCCs) and papillary RCCs via 3p deletion/LOH and deleterious mutations. Histone H3-K36 trimethylation is facilitated by SETD2, which is necessary for proper pre-mRNA intron splicing. Improperly spliced mature mRNA may lead to aberrant translation of retained introns (ATaRI), which represents potential therapeutic vulnerabilities. We explored this hypothesis using real world data and RCC models. Methods and Results: Gene set enrichment analysis comparing SETD2-mutant to WT tumors using samples from the TCGA KIRC data set revealed that the unfolded protein response (UPR) was strongly enriched, as well as several immunotherapy-relevant pathways. This suggested that peptides arising from ATaRI may be present, since they would not be expected to fold properly and thus need to be addressed by the UPR pathway to maintain homeostasis. To investigate this further, we generated Setd2-isogenic RENCA cells using CRISPR. Knockout was confirmed by sequencing and immunoblot. H3K36 trimethylation was decreased or eliminated in monoclonal knockout cell lines, confirming a functional effect. Markers of UPR activation, including Atf4 and cleaved Atf6, were found to be upregulated in Setd2-mutant RENCA cells compared to controls as measured by immunoblot. Cleaved ATF6 translocates to the nucleus to induce the UPR transcriptional program. Consistent with this, Atf6 was found to localize to the nucleus in Setd2-knockout cells using immunofluorescence (IF). Analysis of tissue microarrays of human SETD2-mutant vs -WT ccRCC revealed increased ATF6 signal in areas with low H3K36 tri-methylation, indicating UPR activation in vivo. Interestingly, CHOP, another downstream effector of the UPR pathway which predominantly regulates cell death, did not become upregulated in Setd2-knockout cells, suggesting activation of a compensatory cell survival pathway. Geldanamycin was shown to destabilize the Perk and Ire1a arms of the UPR, which resulted in increased cell death in Setd2 mutant cells using Cell Titre glo. Additionally, H3K36 trimethylation has been implicated in directing homologous repair of DNA, and blunted responses to agents that induce DNA double-strand breaks of p-Atm, p53, and Rad51 were observed by immunoblot and IF. The inability to detect DNA damage in Setd2 mutant cells however did not confer sensitivity to PARP inhibitors. Conclusions: We identify activation of the UPR upon Setd2 loss and suggest that activation of part of the UPR pathway may represent a new therapeutic vulnerability for exploitation as a rationale for personalized medicine. We further characterize the altered DNA damage response in the setting of Setd2 loss. We continue to evaluate the generation of peptides arising from ATaRI in Setd2-mutant contexts. Citation Format: Alexander Metz, Marya Kozinova, Robert Uzzo, Jessica Peskin, Michael Slifker, Janusz Franco-Barraza, Edna Cukierman, Philip Abbosh. SETD2 loss in renal carcinoma cells induces the unfolded protein response [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 3725.

Abstract 3140: Interleukin-34 regulates tumor immune microenvironment of renal cell carcinoma

Abstract Renal Cell Carcinoma (RCC) is a type of kidney cancer which derives from renal tubular epithelial cells and is responsible for approximately 90-95% of cases in adults. Incidence and prevalence of RCC are rising, and 5-year survival of metastatic disease is close to 10%. The therapy of RCC mainly targets the angiogenic and immunosuppressive tumor microenvironment (TME), but it is rarely curative and drug resistance is almost inevitable. Lack of validated biomarkers and scarce knowledge of the biological processes occurring during RCC progression are main reasons of therapy failure. Using an immunocompetent murine model of RCC, we identified Interleukin-34 (IL34) as potential biomarker of RCC progression, whose expression is associated with advanced tumor stage and reduced survival in RCC patients. In cancer, IL34 was demonstrated to regulate cancer cell proliferation and monocytes survival and differentiation into macrophages. Regarding to RCC, IL34 role in the TME still remains elusive and has never been described. To elucidate the function of IL34 in RCC biology, we undertook different approaches: Gene Ontology enrichment analysis of IL34 co-expressed genes, using the KIRC-TCGA database, which revealed that such genes are involved in different immune system related processes; orthotopic implantation of IL34 over-expressing murine renal cancer cells (i.e. RENCA cell line) in BALB/c mice, where we observed, both in primary tumors and lung metastases, an accumulation of tumor associated macrophages (TAM) expressing M2-type macrophage markers (e.g. Cd206 and Cd163). Subsequently, to deeply investigate how IL34 can finely tune the tumor immune microenvironment of RCC, we also employed an experiment of Single Nuclei Sequencing using murine samples over-expressing IL34 (or control empty vector). Briefly, RENCA cancer cells were implanted in BALB/c mice using two different injection modalities: orthotopic implantation in the kidney, to generate primary tumors; 2) tail vein injection, for lung metastases formation. After tumor or metastases formation, samples were snap-frozen in liquid nitrogen and processed for cDNA library preparation for next generation sequencing. Our project aims to elucidate how IL34 can be implicated in the regulation of TME in RCC and, in particular, of the phenotype of the accumulated TAM. As TAM are known to promote cancer progression by enhancing tumor angiogenesis and immunosuppression, the study of IL34 role in the TME can reveal novel paradigms in RCC biology, and may be fundamental to improve the current therapy (e.g. using drugs targeting IL34 activity). Citation Format: Andrea Emanuelli, Wilfried Souleyreau, Tiffanie Chouleur, Marie-Alix Derieppe, Andreas Bikfalvi. Interleukin-34 regulates tumor immune microenvironment of renal cell carcinoma [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 3140.

Spheroid culture models adequately imitate distinctive features of the renal cancer or melanoma microenvironment.

Tumor development studies should adapt to cancer cells' specific mechanisms in connection with their microenvironment. Standard two-dimensional cultures and gas composition are not relevant to the real cancer environment. Existing three-dimensional models are often requiring sophisticated conditions. Here, we propose and characterize, in two cancer models, melanoma (B16F10) and kidney cancer (RenCa), a three-dimensional culture method, reporting the presence of hypoxia-related genes/proteins and aggressiveness mechanisms (epithelial mesenchymal transition and cancer stem cells). We validate the designed three-dimensional method by comparing it with in vivo growing tumors. The developed method brings simplicity and data reproducibility. Melanoma spheroid-growing cells reached a cell cycle arrest at the G0/G1 phase and showed induction of hypoxia. Spheroid-recovered RenCa cells were enriched in proliferating cells and displayed delayed hypoxia. Moreover, the responses to hypoxia observed in spheroids were validated by in vivo tumor studies for both lines. Three-dimensional shapes induced cancer stem cells in renal cancer, whereas epithelial to mesenchymal transition occurred in the melanoma model. Such distinction in the use of different aggressiveness-leading pathways was observed in in vivo melanoma vs kidney tumors. Thus, this 3D culture model approach is adequate to uncover crucial molecular pathways using distinct mechanisms to reach aggressiveness; i.e., B16F10 cells perform epithelial to mesenchymal transition while RenCa cells dedifferentiate into cancer stem cells. Such three-dimensional models help mimic the in vivo tumor features, i.e., hypoxia and aggressiveness mechanisms as validated here by next-generation sequencing analysis, and are proposed for further alternative methods to in vivo studies.

Abstract P012: Investigation of interleukin-34 dependent regulation of renal carcinoma tumor microenvironment

Abstract In 2020, Renal Carcinoma (RC) accounted for around 179,000 worldwide deaths and its mortality is predicted to double in the next 20 years. The major issue for RC patients is the absence of an efficient therapeutic option, especially for metastatic forms of the disease where the 5-years survival rate is close to 10%. The therapy of RC mainly targets the angiogenic and immunosuppressive tumor microenvironment (TME), but it is rarely curative and drug resistance is almost inevitable. Lack of validated biomarkers and scarce knowledge of the biological processes occurring during RC progression are main reasons of therapy failure. In our unpublished work, using a syngeneic murine model of RC, we identified interleukin-34 (IL34) as potential biomarker of RC progression. In particular, we observed that increased IL34 expression was associated with enhanced cancer cell aggressiveness and reduced survival both in mice and in RC patients from two different cohorts (i.e. KIRC-TCGA, and UroCCR local cohort). IL34 exerts pleiotropic functions in different biological processes, including immunity regulation, cell proliferation and monocytes survival and differentiation into macrophages. The expression of IL34 in the TME is heterogeneous between cancer types, and high IL34 levels can represent either a poor (i.e. in brain and lung cancers) or a favorable (i.e. in neck and breast cancers) prognostic factor. Regarding to RC, IL34 role in the TME still remains elusive and has never been described. For this reason, using the KIRC-TCGA database, we performed Gene Ontology enrichment analysis using a list of IL34 co-expressed genes to predict potential IL34 regulatory functions in the TME of RC patients. This analysis revealed that such genes are involved in different immune system related processes, including positive regulation of leukocyte activation, IL-10 production and adaptive immune response. Subsequently, using IL34-overexpressing murine renal carcinoma RENCA cells implanted in BALB/c mice, we investigated the IL34-dependent alteration of the tumor immune microenvironment. In particular, we observed that, both in generated primary tumors and lung metastases, IL34 increased the density of tumor associated macrophages (TAM), which expressed M2-type markers (e.g. Cd206 and Cd163). Furthermore, in these samples, qPCR analysis showed an increase of interleukin-10 gene expression suggesting that IL34 could induce an immunosuppressive microenvironment. Conversely, when we blocked IL34 activity in lung metastases using an inhibitor of CSF1R, the main receptor of IL34, we observed a significant reduction in TAM accumulation and Il10 expression. The major aim of this project is to investigate whether IL34 can sustain immunosuppression and, consequently, chemoresistance by accumulating TAM in the TME. Furthermore, the IL34-dependent regulation of other immune cell populations (e.g. T-reg or myeloid-derived suppressor cells) is under investigation. The study of IL34 role in the TME of RC can be fundamental to improve the current therapy. Citation Format: Andrea Emanuelli, Wilfried Souleyreau, Lindsay Cooley, Tiffanie Chouleur, Marie-Alix Derieppe, Jean-Christophe Bernhard, Andreas Bikfalvi. Investigation of interleukin-34 dependent regulation of renal carcinoma tumor microenvironment [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P012.

Functional Genomic and Immune Response Characterization of PTEN Loss: Therapeutic Implications for Myeloma

PTEN (phosphatase and tensin homolog) is a known tumor suppressor gene (TSG) in solid tumors and hematologic malignancies, including multiple myeloma (MM), yet several aspects of its biology and clinical implications remain incompletely understood in MM. For instance, PTEN mutations/deletions are infrequent in newly diagnosed MM in the CoMMpass study (6 and 9 cases with heterozygous mutations or loss of one PTEN gene copy, respectively in 957 patients, IA16; no evidence of bi-allelic loss), and there is no enrichment for PTEN transcript suppression or biallelic PTEN loss at relapse. Moreover, while MM cell lines are considered to reflect advanced relapsed/refractory MM, nearly all are PTEN-proficient (with notable exceptions e.g. biallelic loss in OPM2). These considerations raise a question whether PTEN loss is indeed functionally associated with a competitive advantage for MM cells compared to their PTEN-proficient counterparts. In genome-scale CRISPR-Cas9 gene editing (knockout, KO) screens we observed that 16/19 MM cell lines exhibited CERES or CHRONOS scores >0.4, consistent with the proposed role of PTEN as a negative regulator of survival and proliferation: the 3 outlier cell lines included OPM2 (biallelic PTEN deletion) and 2 other lines (SKMM2 and AMO1) with no obvious genetic events suppressing PTEN function or causing constitutive activation of PI3K/Akt/mTOR signaling. We performed subgenome-scale CRISPR KO screens with focused libraries of single guide RNAs (sgRNAs) for several known (including PTEN) or candidate TSGs and control sgRNAs from MM and other tumors in vitro and confirmed that in vitro enrichment of PTEN KO in several PTEN-proficient (but not -deficient lines), consistent with the genome-scale CRISPR study results. These observations were further confirmed with in vitro competition assays where isogenic Cas9+ cells transduced with sgRNAs against PTEN or olfactory receptor (OR) genes (as DNA-cutting negative controls) were mixed, cultured for 4-12 weeks and DNA sequenced for the distribution of their sgRNAs, and determined a significant relative enrichment of PTEN KOs compared to their OR KO counterparts. Importantly, when cells harboring focused sub-genome scale sgRNA library were implanted in vivo in a bicalcium phosphate scaffold-based bone marrow (BM)-like model with a “humanized” mesenchymal bone stromal cell compartment, we observed that CRISPR KO of PTEN represented the top enriched gene perturbation in the PTEN-proficient MM cell lines MM.1S and KMS11 (not the AMO1 line) in vivo, consistent with the in vitro results. Collectively, these observations indicate that while PTEN deficiency is infrequent in newly diagnosed MM patient samples and in preclinical cell line models that reflect advanced disease, PTEN KO is associated with major “fitness” advantage for MM cells in preclinical in vitro and in vivo xenograft models, i.e. systems in which tumor cell “fitness” does not account for potential immunogenicity of human tumor cells. We hypothesized that PTEN KO remain highly immunogenic which curtails their “fitness” advantage: indeed, we observed in a series of CRISPR KO screens in PTEN-proficient cell lines from MM, other hematologic malignancies or solid tumors, PTEN loss was not associated with increased resistance to allogeneic donor-derived NK cells (in-house studies) or T-cell treatment (e.g. 41T, RENCA cells; GSE149933). In fact, for some MM cell lines (e.g. MM1S, KMS11), PTEN KO led to more pronounced sensitivity to NK cells (compared to control OR KOs) in genome-scale or focused CRISPR screens, and in validation experiments with individual sgRNAs for PTEN (vs. OR gene sgRNAs). While our functional genomic studies document that PTEN loss confers a generalizable “fitness advantage” for MM lines in vitro and in immunocompromised in vivo models, the limited, if any, association of advanced MM with PTEN loss raises intriguing questions about the potentially complex role of PTEN as a TSG. While alternative hypotheses are plausible, our results point to the immune responses of PTEN-deficient tumor cells as an additional factor that can reconcile our integrated observations in molecular annotated clinical samples and preclinical functional genomic studies. DisclosuresTsherniak: Cedilla Therapeutics: Consultancy; Foghorn Therapeutics: Consultancy; The Center for Protein Degradation: Consultancy; SAB: Membership on an entity's Board of Directors or advisory committees. Licht: Epizyme: Research Funding. Boise: Abbvie: Consultancy; AstraZeneca: Consultancy, Research Funding. Mitsiades: Arch Oncology: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding; FIMECS: Consultancy, Honoraria; EMD Serono: Research Funding; Abbvie: Research Funding; Nurix: Research Funding; Janssen/Johnson & Johnson: Research Funding; BMS: Research Funding; Ionis Pharmaceuticals: Consultancy, Honoraria; Fate Therapeutics: Consultancy, Honoraria; Adicet Bio: Membership on an entity's Board of Directors or advisory committees; TEVA: Research Funding; Novartis: Research Funding; H3 Biomedicine: Research Funding.

Composition of EVs markers under normoxic and hypoxic conditions depends on the expression level of adaptor protein Ruk/CIN85 in mouse renal carcinoma Renca cells

Composition of EVs markers under normoxic and hypoxic conditions depends on the expression level of adaptor protein Ruk/CIN85 in mouse renal carcinoma Renca cells