mTOR inhibitors in renal cell carcinoma

Targeting the RAS upstream and downstream signaling pathway for cancer treatment

Cancer often involves the overactivation of RAS/RAF/MEK/ERK (MAPK) and PI3K-Akt-mTOR pathways due to mutations in genes like RAS, RAF, PTEN, and PIK3CA. Various strategies are employed to address the overactivation of these pathways, among which targeted therapy emerges as a promising approach. Directly targeting specific proteins, leads to encouraging results in cancer treatment. For instance, RTK inhibitors such as imatinib and afatinib selectively target these receptors, hindering ligand binding and reducing signaling initiation. These inhibitors have shown potent efficacy against Non-Small Cell Lung Cancer. Other inhibitors, like lonafarnib targeting Farnesyltransferase and GGTI 2418 targeting geranylgeranyl Transferase, disrupt post-translational modifications of proteins. Additionally, inhibition of proteins like SOS, SH2 domain, and Ras demonstrate promising anti-tumor activity both in vivo and in vitro. Targeting downstream components with RAF inhibitors such as vemurafenib, dabrafenib, and sorafenib, along with MEK inhibitors like trametinib and binimetinib, has shown promising outcomes in treating cancers with BRAF-V600E mutations, including myeloma, colorectal, and thyroid cancers. Furthermore, inhibitors of PI3K (e.g., apitolisib, copanlisib), AKT (e.g., ipatasertib, perifosine), and mTOR (e.g., sirolimus, temsirolimus) exhibit promising efficacy against various cancers such as Invasive Breast Cancer, Lymphoma, Neoplasms, and Hematological malignancies. This review offers an overview of small molecule inhibitors targeting specific proteins within the RAS upstream and downstream signaling pathways in cancer.

Lipid metabolism reprogramming in renal cell carcinomas

This study investigates the intricate mechanisms underlying the correlation between elevated consumption of harmful fats and the onset of kidney malignancies. The rise in global obesity rates has been accompanied by an increased prevalence of renal cancers, prompting an exploration into the molecular pathways and biological processes linking these phenomena. Through an extensive review of current literature and clinical studies, we identify potential key factors contributing to the carcinogenic influence of harmful fats on renal tissues. Our analysis highlights the role of adipose tissue-derived factors, inflammatory mediators, and lipid metabolism dysregulation in fostering a microenvironment conducive to renal tumorigenesis. Furthermore, we delve into the impact of harmful fats on signaling pathways associated with cell proliferation, apoptosis evasion, and angiogenesis within the renal parenchyma. This review underscores the importance of elucidating the molecular intricacies linking lipid metabolism and kidney malignancies, offering a foundation for future research and the development of targeted preventive and therapeutic interventions. The findings discussed herein contribute to our understanding of the complex relationship between lipid mediators and renal cancer, providing a basis for public health strategies aimed at mitigating the impact of harmful fats on kidney health.

Renal cancer: signaling pathways and advances in targeted therapies

Renal cancer is a highlyheterogeneous malignancy characterized by rising global incidence and mortalityrates. The complex interplay and dysregulation of multiple signaling pathways,including von Hippel-Lindau (VHL)/hypoxia-inducible factor (HIF), phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR), Hippo-yes-associated protein (YAP), Wnt/ß-catenin, cyclic adenosine monophosphate (cAMP), and hepatocyte growth factor (HGF)/c-Met, contribute to theinitiation and progression of renal cancer. Although surgical resection is thestandard treatment for localized renal cancer, recurrence and metastasiscontinue to pose significant challenges. Advanced renal cancer is associatedwith a poor prognosis, and current therapies, such as targeted agents andimmunotherapies, have limitations. This review presents a comprehensiveoverview of the molecular mechanisms underlying aberrant signaling pathways inrenal cancer, emphasizing their intricate crosstalk and synergisticinteractions. We discuss recent advancements in targeted therapies, includingtyrosine kinase inhibitors, and immunotherapies, such as checkpoint inhibitors.Moreover, we underscore the importance of multiomics approaches and networkanalysis in elucidating the complex regulatory networks governing renal cancerpathogenesis. By integrating cutting-edge research and clinical insights, this review contributesto the development of innovative diagnostic and therapeutic strategies, whichhave the potential to improve risk stratification, precision medicine, andultimately, patient outcomes in renal cancer.

Clinical, Genomic, and Transcriptomic Characteristics of Patients with Metastatic Renal Cell Carcinoma Who Developed Thromboembolic Events

Thromboembolic events (TE) are a common complication in patients with metastatic renal cell carcinoma (mRCC) and are associated with poorer clinical outcomes. However, the incidence of TE and clinical and genomic characteristics of patients with mRCC who develop this complication are poorly understood. Herein, we describe the incidence and clinical features of patients with mRCC with or without TE at our institution, and examine their association with the underlying genomic and transcriptomic characteristics of the tumor. This retrospective study included all consecutive cases of mRCC seen at our institution. A CLIA-certified lab performed tumor genomics and transcriptomics. Patients were classified based on the presence of a TE within the first year of diagnosis. Three hundred and seventy patients with mRCC were included in the study. TE was seen in 11% (42) of the patients. Patients with favorable International mRCC Database Consortium (IMDC) risk were less likely to develop a TE. In contrast, patients receiving combination treatment with a tyrosine kinase inhibitor (TKI) and an immune checkpoint inhibitor were more likely to develop a TE. No difference in overall survival among patients with or without TE was observed (52 vs. 55 months; HR 0.85, 95% CI 0.5574-1.293, p = 0.24). The most upregulated pathways in mRCC with TEs versus those without were the xenobiotic metabolism and mTORC1 signaling pathways. Our findings suggest potential biomarkers that, after external validation, could be used to better select patients who would benefit from prophylactic anticoagulation.

Targeting mTOR and survivin concurrently potentiates radiation therapy in renal cell carcinoma by suppressing DNA damage repair and amplifying mitotic catastrophe

BACKGROUND

Renal cell carcinoma (RCC) was historically considered to be less responsive to radiation therapy (RT) compared to other cancer indications. However, advancements in precision high-dose radiation delivery through single-fraction and multi-fraction stereotactic ablative radiotherapy (SABR) have led to better outcomes and reduced treatment-related toxicities, sparking renewed interest in using RT to treat RCC. Moreover, numerous studies have revealed that certain therapeutic agents including chemotherapies can increase the sensitivity of tumors to RT, leading to a growing interest in combining these treatments. Here, we developed a rational combination of two radiosensitizers in a tumor-targeted liposomal formulation for augmenting RT in RCC. The objective of this study is to assess the efficacy of a tumor-targeted liposomal formulation combining the mTOR inhibitor everolimus (E) with the survivin inhibitor YM155 (Y) in enhancing the sensitivity of RCC tumors to radiation.

EXPERIMENTAL DESIGN

We slightly modified our previously published tumor-targeted liposomal formulation to develop a rational combination of E and Y in a single liposomal formulation (EY-L) and assessed its efficacy in RCC cell lines in vitro and in RCC tumors in vivo. We further investigated how well EY-L sensitizes RCC cell lines and tumors toward radiation and explored the underlying mechanism of radiosensitization.

RESULTS

EY-L outperformed the corresponding single drug-loaded formulations E-L and Y-L in terms of containing primary tumor growth and improving survival in an immunocompetent syngeneic mouse model of RCC. EY-L also exhibited significantly higher sensitization of RCC cells towards radiation in vitro than E-L and Y-L. Additionally, EY-L sensitized RCC tumors towards radiation therapy in xenograft and murine RCC models. EY-L mediated induction of mitotic catastrophe via downregulation of multiple cell cycle checkpoints and DNA damage repair pathways could be responsible for the augmentation of radiation therapy.

CONCLUSION

Taken together, our study demonstrated the efficacy of a strategic combination therapy in sensitizing RCC to radiation therapy via inhibition of DNA damage repair and a substantial increase in mitotic catastrophe. This combination therapy may find its use in the augmentation of radiation therapy during the treatment of RCC patients.

Clinical practice recommendations for kidney involvement in tuberous sclerosis complex: a consensus statement by the ERKNet Working Group for Autosomal Dominant Structural Kidney Disorders and the ERA Genes & Kidney Working Group

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the presence of proliferative lesions throughout the body. Management of TSC is challenging because patients have a multifaceted systemic illness with prominent neurological and developmental impact as well as potentially severe kidney, heart and lung phenotypes; however, every organ system can be involved. Adequate care for patients with TSC requires a coordinated effort involving a multidisciplinary team of clinicians and support staff. This clinical practice recommendation was developed by nephrologists, urologists, paediatric radiologists, interventional radiologists, geneticists, pathologists, and patient and family group representatives, with a focus on TSC-associated kidney manifestations. Careful monitoring of kidney function and assessment of kidney structural lesions by imaging enable early interventions that can preserve kidney function through targeted approaches. Here, we summarize the current evidence and present recommendations for the multidisciplinary management of kidney involvement in TSC.

Rationale for immune checkpoint inhibitors plus targeted therapy for advanced renal cell carcinoma

Renal cell carcinoma (RCC) is a frequent urological malignancy characterized by a high rate of metastasis and lethality. The treatment strategy for advanced RCC has moved through multiple iterations over the past three decades. Initially, cytokine treatment was the only systemic treatment option for patients with RCC. With the development of medicine, antiangiogenic agents targeting vascular endothelial growth factor and mammalian target of rapamycin and immunotherapy, immune checkpoint inhibitors (ICIs) have emerged and received several achievements in the therapeutics of advanced RCC. However, ICIs have still not brought completely satisfactory results due to drug resistance and undesirable side effects. For the past years, the interests form researchers have been attracted by the combination of ICIs and targeted therapy for advanced RCC and the angiogenesis and immunogenic tumor microenvironmental variations in RCC. Therefore, we emphasize the potential principle and the clinical progress of ICIs combined with targeted treatment of advanced RCC, and summarize the future direction.

The Therapeutic Efficacy and Mechanism of Action of Gnetin C, a Natural Compound from the Melinjo Plant, in a Preclinical Mouse Model of Advanced Prostate Cancer

The metastasis-associated protein 1/protein kinase B (MTA1/AKT) signaling pathway has been shown to cooperate in promoting prostate tumor growth. Targeted interception strategies by plant-based polyphenols, specifically stilbenes, have shown great promise against MTA1-mediated prostate cancer progression. In this study, we employed a prostate-specific transgenic mouse model with MTA1 overexpression on the background of phosphatase and tensin homolog (Pten) null (R26MTA1; Ptenf/f) and PC3M prostate cancer cells which recapitulate altered molecular pathways in advanced prostate cancer. Mechanistically, the MTA1 knockdown or pharmacological inhibition of MTA1 by gnetin C (dimer resveratrol) in cultured PC3M cells resulted in the marked inactivation of mammalian target of rapamycin (mTOR) signaling. In vivo, mice tolerated a daily intraperitoneal treatment of gnetin C (7 mg/kg bw) for 12 weeks without any sign of toxicity. Treatment with gnetin C markedly reduced cell proliferation and angiogenesis and promoted apoptosis in mice with advanced prostate cancer. Further, in addition to decreasing MTA1 levels in prostate epithelial cells, gnetin C significantly reduced mTOR signaling activity in prostate tissues, including the activity of mTOR-target proteins: p70 ribosomal protein S6 kinase (S6K) and eukaryotic translational initiation factor 4E (elF4E)-binding protein 1 (4EBP1). Collectively, these findings established gnetin C as a new natural compound with anticancer properties against MTA1/AKT/mTOR-activated prostate cancer, with potential as monotherapy and as a possible adjunct to clinically approved mTOR pathway inhibitors in the future.

Targeting hypoxia-inducible factors: therapeutic opportunities and challenges

Hypoxia-inducible factors (HIFs) are highly conserved transcription factors that are crucial for adaptation of metazoans to limited oxygen availability. Recently, HIF activation and inhibition have emerged as therapeutic targets in various human diseases. Pharmacologically desirable effects of HIF activation include erythropoiesis stimulation, cellular metabolism optimization during hypoxia and adaptive responses during ischaemia and inflammation. By contrast, HIF inhibition has been explored as a therapy for various cancers, retinal neovascularization and pulmonary hypertension. This Review discusses the biochemical mechanisms that control HIF stabilization and the molecular strategies that can be exploited pharmacologically to activate or inhibit HIFs. In addition, we examine medical conditions that benefit from targeting HIFs, the potential side effects of HIF activation or inhibition and future challenges in this field.

Targeting mTOR and Survivin Concurrently Potentiates Radiation Therapy in Renal Cell Carcinoma by Suppressing DNA Damage Repair and Amplifying Mitotic Catastrophe

Background

Renal cell carcinoma (RCC) was historically considered to be less responsive to radiation therapy (RT) compared to other cancer indications. However, advancements in precision high-dose radiation delivery through single-fraction and multi-fraction stereotactic ablative radiotherapy (SABR) have led to better outcomes and reduced treatment-related toxicities, sparking renewed interest in using RT to treat RCC. Moreover, numerous studies have revealed that certain therapeutic agents including chemotherapies can increase the sensitivity of tumors to RT, leading to a growing interest in combining these treatments. Here, we developed a rational combination of two radiosensitizers in a tumor-targeted liposomal formulation for augmenting RT in RCC. The objective of this study is to assess the efficacy of a tumor-targeted liposomal formulation combining the mTOR inhibitor everolimus (E) with the survivin inhibitor YM155 (Y) in enhancing the sensitivity of RCC tumors to radiation.

Experimental Design

We slightly modified our previously published tumor-targeted liposomal formulation to develop a rational combination of E and Y in a single liposomal formulation (EY-L) and assessed its efficacy in RCC cell lines in vitro and in RCC tumors in vivo. We further investigated how well EY-L sensitizes RCC cell lines and tumors toward radiation and explored the underlying mechanism of radiosensitization.

Results

EY-L outperformed the corresponding single drug-loaded formulations E-L and Y-L in terms of containing primary tumor growth and improving survival in an immunocompetent syngeneic mouse model of RCC. EY-L also exhibited significantly higher sensitization of RCC cells towards radiation in vitro than E-L and Y-L. Additionally, EY-L sensitized RCC tumors towards radiation therapy in xenograft and murine RCC models. EY-L mediated induction of mitotic catastrophe via downregulation of multiple cell cycle checkpoints and DNA damage repair pathways could be responsible for the augmentation of radiation therapy.

Conclusion

Taken together, our study demonstrated the efficacy of a strategic combination therapy in sensitizing RCC to radiation therapy via inhibition of DNA damage repair and a substantial increase in mitotic catastrophe. This combination therapy may find its use in the augmentation of radiation therapy during the treatment of RCC patients.

Positive GPNMB Immunostaining Differentiates Renal Cell Carcinoma With Fibromyomatous Stroma Associated With TSC1/2/MTOR Alterations From Others

Renal cell carcinoma with fibromyomatous stroma (RCCFMS) include ELOC/TCEB1 -mutated renal cell carcinoma (RCC) and those with TSC1/2 / MTOR alterations. Besides morphologic similarity, most of these tumors is known to be diffusely positive for carbonic anhydrase IX and cytokeratin 7 by immunohistochemistry. We previously showed strong and diffuse expression of GPNMB (glycoprotein nonmetastatic B) in translocation RCC and eosinophilic renal neoplasms with known TSC1/2/MTOR alterations. We retrospectively identified molecularly confirmed cases of TCEB1/ELOC -mutated RCC (7 tumors from 7 patients), and RCCFMS with alterations in TSC1/2/MTOR (6 tumors from 5 patients, 1 patient with tuberous sclerosis syndrome). In addition, we included 7 clear cell papillary renal cell tumors (CCPRCTs) and 8 clear cell RCC, as they can also present morphologic overlap with RCCFMS. Morphologically, RCCs with TSC1/2/MTOR alterations and those with TCEB1/ELOC mutations were indistinguishable and characterized by papillary, nested, or tubular architecture, with tumor cells with clear cytoplasm and low nuclear grade. By immunohistochemistry, cytokeratin 7 was positive in 5/7 (71%) of TCEB1/ELOC -mutated RCCs, 6/6 (100%) of RCCs with TSC1/2/mTOR alterations, and 7/7 (100%) of CCPRCTs ( P =not significant). Carbonic anhydrase IX was positive in 7/7 TCEB1/ELOC -mutated RCCs, 6/6 (100%) of RCCs with TSC1/2/MTOR alterations, and 7/7 (100%) of CCPRCTs ( P =NS). GPNMB was strongly and diffusely positive in all tumors with TSC1/2/MTOR alterations (6/6), while negative in all TCEB1/ELOC -mutated RCCs (0/6), or CCPRCTs (0/7) ( P =0.002). Two of 8 clear cell RCC showed focal weak staining, while 6/8 were negative. In conclusion, the results support the use of GPNMB to distinguish RCCFMS with TSC1/2/MTOR alterations from others with similar morphology.

An Overview of Renal Cell Carcinoma Hallmarks, Drug Resistance, and Adjuvant Therapies

Renal neoplasms are highlighted as one of the 10 most common types of cancer. Renal cell carcinoma (RCC) is the most common type of renal cancer, considered the seventh most common type of cancer in the Western world. The most frequently altered genes described as altered are VHL, PBRM1, SETD2, KDM5C, PTEN, BAP1, mTOR, TP53, TCEB1 (ELOC), SMARCA4, ARID1A, and PIK3CA. RCC therapies can be classified in three groups: monoclonal antibodies, tyrosine kinase inhibitors, and mTOR inhibitors. Besides, there are targeted agents to treat RCC. However, frequently patients present side effects and resistance. Even though many multidrug resistance mechanisms already have been reported to RCC, studies focused on revealing new biomarkers as well as more effective antitumor therapies with no or low side effects are very important. Some studies reported that natural products, such as honey, epigallocatechin-3-gallate (EGCG), curcumin, resveratrol, and englerin A showed antitumor activity against RCC. Moreover, nanoscience is another strategy to improve RCC treatment and reduce the side effects due to the improvement in pharmacokinetics and reduction of toxicities of chemotherapies. Taking this into account, we conducted a systemic review of recent research findings on RCC hallmarks, drug resistance, and adjuvant therapies. In conclusion, a range of studies reported that RCC is characterized by high incidence and increased mortality rates because of the development of resistance to standard therapies. Given the importance of improving RCC treatment and reducing adverse effects, nanoscience and natural products can be included in therapeutic strategies.

ExPert ConsEnsus on the management of Advanced clear-cell RenaL celL carcinoma: INDIAn Perspective (PEARL-INDIA)

In advanced Renal Cell Carcinoma (aRCC), systemic therapy is the mainstay of treatment, with no or little role for surgery in these patients. Tyrosine kinase inhibitors (TKIs) and immune-oncological (IOs) therapies, either alone or in combination, are recommended in these patients depending on patient and tumour factors. The sequencing of therapies is critical in RCC because the choice of subsequent line therapy is heavily dependent on the response and duration of the previous treatment. There are additional barriers to RCC treatment in India. Immunotherapy is the cornerstone of treatment in ccRCC, but it is prohibitively expensive and not always reimbursed, effectively putting it out of reach for the vast majority of eligible patients in India. Furthermore, in advanced RCC (particularly the clear cell variety), Indian oncologists consider the disease burden of the patients, which is particularly dependent on the quantum of the disease load, clinical symptoms, and performance status of the patient, before deciding on treatment. There are no India-specific guidelines for clear cell RCC (ccRCC) treatment or the positioning and sequencing of molecules in the management of advanced ccRCC that take these country-specific issues into account. The current consensus article provides expert recommendations and treatment algorithms based on existing clinical evidence, which will be useful to specialists managing advanced ccRCC.

Proteotranscriptomic Discrimination of Tumor and Normal Tissues in Renal Cell Carcinoma

Clear cell renal carcinoma is the most frequent type of kidney cancer, with an increasing incidence rate worldwide. In this research, we used a proteotranscriptomic approach to differentiate normal and tumor tissues in clear cell renal cell carcinoma (ccRCC). Using transcriptomic data of patients with malignant and paired normal tissue samples from gene array cohorts, we identified the top genes over-expressed in ccRCC. We collected surgically resected ccRCC specimens to further investigate the transcriptomic results on the proteome level. The differential protein abundance was evaluated using targeted mass spectrometry (MS). We assembled a database of 558 renal tissue samples from NCBI GEO and used these to uncover the top genes with higher expression in ccRCC. For protein level analysis 162 malignant and normal kidney tissue samples were acquired. The most consistently upregulated genes were IGFBP3, PLIN2, PLOD2, PFKP, VEGFA, and CCND1 (p < 10^-5 for each gene). Mass spectrometry further validated the differential protein abundance of these genes (IGFBP3, p = 7.53 × 10^-18; PLIN2, p = 3.9 × 10^-39; PLOD2, p = 6.51 × 10^-36; PFKP, p = 1.01 × 10^-47; VEGFA, p = 1.40 × 10^-22; CCND1, p = 1.04 × 10^-24). We also identified those proteins which correlate with overall survival. Finally, a support vector machine-based classification algorithm using the protein-level data was set up. We used transcriptomic and proteomic data to identify a minimal panel of proteins highly specific for clear cell renal carcinoma tissues. The introduced gene panel could be used as a promising tool in the clinical setting.

Phosphorylation of OTUB1 at Tyr 26 stabilizes the mTORC1 component, Raptor

Raptor plays a critical role in mTORC1 signaling. High expression of Raptor is associated with resistance of cancer cells to PI3K/mTOR inhibitors. Here, we found that OTUB1-stabilized Raptor in a non-canonical manner. Using biochemical assays, we found that the tyrosine 26 residue (Y26) of OTUB1 played a critical role in the interaction between OTUB1 and Raptor. Furthermore, non-receptor tyrosine kinases (Src and SRMS kinases) induced phosphorylation of OTUB1 at Y26, which stabilized Raptor. Interestingly, phosphorylation of OTUB1 at Y26 did not affect the stability of other OTUB1-targeted substrates. However, dephosphorylation of OTUB1 destabilized Raptor and sensitized cancer cells to anti-cancer drugs via mitochondrial reactive oxygen species-mediated mitochondrial dysfunction. Furthermore, we detected high levels of phospho-OTUB1 and Raptor in samples of patients with renal clear carcinoma. Our results suggested that regulation of OTUB1 phosphorylation may be an effective and selective therapeutic target for treating cancers via down-regulation of Raptor.

Randomized Phase II Trial of Sapanisertib ± TAK-117 vs. Everolimus in Patients With Advanced Renal Cell Carcinoma After VEGF-Targeted Therapy

BACKGROUND

Sapanisertib, a dual mTORC1/2 inhibitor, may offer more complete inhibition of the PI3K/AKT/mTOR pathway than mTORC1 inhibitors, such as everolimus. This phase II study evaluated the efficacy and safety of single-agent sapanisertib and sapanisertib plus the PI3Kα inhibitor TAK-117, vs. everolimus in patients with advanced clear cell renal cell carcinoma (ccRCC) that had progressed on or after VEGF-targeted therapy.

MATERIALS AND METHODS

Patients with histologically confirmed, advanced ccRCC were randomized 1:1:1 to receive single-agent everolimus 10 mg once daily, single-agent sapanisertib 30 mg once weekly, or sapanisertib 4 mg plus TAK-117 200 mg, both once daily for 3 days/week, in 28-day cycles. The primary endpoint was progression-free survival (PFS).

RESULTS

Ninety-five patients were treated with everolimus or sapanisertib (n = 32 each), or sapanisertib plus TAK-117 (n = 31). There were no significant differences in PFS among the 3 groups or across any subgroups. Median PFS was 3.8 months with everolimus vs. 3.6 months with sapanisertib (HR, 1.33; 95% CI, 0.75-2.36), and 3.1 months with sapanisertib plus TAK-117 (HR, 1.37; 95% CI, 0.75-2.52). No significant differences in overall survival were seen among groups. Overall response rate was 16.7%, 0%, and 7.1%, respectively. Discontinuations due to treatment-emergent adverse events were 15.6%, 28.1%, and 29.0%.

CONCLUSION

Sapanisertib with or without TAK-117 was less tolerable and did not improve efficacy vs. everolimus in patients with advanced ccRCC who had relapsed after or were refractory to VEGF-targeted therapies. Dual mTORC1/2 inhibition may not be an effective therapeutic approach for these patients.

L-Serine-Modified Poly-L-Lysine as a Biodegradable Kidney-Targeted Drug Carrier for the Efficient Radionuclide Therapy of Renal Cell Carcinoma

In the present study, L-serine (Ser)-modified poly-L-lysine (PLL) was synthesized to develop a biodegradable, kidney-targeted drug carrier for efficient radionuclide therapy in renal cell carcinoma (RCC). Ser-PLL was labeled with ¹¹¹In/⁹⁰Y via diethylenetriaminepentaacetic acid (DTPA) chelation for biodistribution analysis/radionuclide therapy. In mice, approximately 91% of the total dose accumulated in the kidney 3 h after intravenous injection of ¹¹¹In-labeled Ser-PLL. Single-photon emission computed tomography/computed tomography (SPECT/CT) imaging showed that ¹¹¹In-labeled Ser-PLL accumulated in the renal cortex following intravenous injection. An intrarenal distribution study showed that fluorescein isothiocyanate (FITC)-labeled Ser-PLL accumulated mainly in the renal proximal tubules. This pattern was associated with RCC pathogenesis. Moreover, ¹¹¹In-labeled Ser-PLL rapidly degraded and was eluted along with the low-molecular-weight fractions of the renal homogenate in gel filtration chromatography. Continuous Ser-PLL administration over five days had no significant effect on plasma creatinine, blood urea nitrogen (BUN), or renal histology. In a murine RCC model, kidney tumor growth was significantly inhibited by the administration of the beta-emitter ⁹⁰Y combined with Ser-PLL. The foregoing results indicate that Ser-PLL is promising as a biodegradable drug carrier for kidney-targeted drug delivery and efficient radionuclide therapy in RCC.

A comprehensive analysis of FOX family in HCC and experimental evidence to support the oncogenic role of FOXH1

Hepatocellular carcinoma (HCC) remains the second leading cause of cancer related deaths worldwide. Understanding about the molecular biology of HCC and development of targeted therapies are still the main focuses of this type of disease. Here, by connecting the expression levels of FOX proteins with their associated clinical characteristics using TCGA LIHC dataset, we found that 27/40 FOX proteins were highly expressed in HCC tumors compared to normal liver tissues and their expression levels were tightly associated with HCC tumor stage, tumor grade and overall survival. Our experimental results also confirmed that FOXH1 indeed played an oncogenic role in HCC development by promoting cell growth and cell migration/invasion. Mechanistic dissection demonstrated that FOXH1-induced cell growth and cell migration/invasion relied on mTOR signaling because inhibition of mTOR signaling by rapamycin could attenuate FOXH1-mediated phenotypic alterations of HCC cells. The results from orthotopic mouse model also validated that FOXH1 promoted HA22T tumor growth via triggering mTOR activation. Overall, this study not only comprehensively examines the clinical values of FOX proteins in HCC but also provides experimental evidence to support the role of FOXH1 in HCC development, building rationale to develop more effective therapies to treat HCC patients.

Lipid metabolism reprogramming in renal cell carcinoma

Metabolic reprogramming is recognized as a hallmark of cancer. Lipids are the essential biomolecules required for membrane biosynthesis, energy storage, and cell signaling. Altered lipid metabolism allows tumor cells to survive in the nutrient-deprived environment. However, lipid metabolism remodeling in renal cell carcinoma (RCC) has not received the same attention as in other cancers. RCC, the most common type of kidney cancer, is associated with almost 15,000 death in the USA annually. Being refractory to conventional chemotherapy agents and limited available targeted therapy options has made the treatment of metastatic RCC very challenging. In this article, we review recent findings that support the importance of synthesis and metabolism of cholesterol, free fatty acids (FFAs), and polyunsaturated fatty acids (PUFAs) in the carcinogenesis and biology of RCC. Delineating the detailed mechanisms underlying lipid reprogramming can help to better understand the pathophysiology of RCC and to design novel therapeutic strategies targeting this malignancy.

Integrative Analysis of the Genomic and Immune Microenvironment Characteristics Associated With Clear Cell Renal Cell Carcinoma Progression: Implications for Prognosis and Immunotherapy

Unlike early clear cell renal cell carcinoma (ccRCC), locally advanced and metastatic ccRCC present poor treatment outcomes and prognosis. As immune checkpoint inhibitors have achieved favorable results in the adjuvant treatment of metastatic ccRCC, we aimed to investigate the immunogenomic landscape during ccRCC progression and its potential impact on immunotherapy and prognosis. Using multi-omics and immunotherapy ccRCC datasets, an integrated analysis was performed to identify genomic alterations, immune microenvironment features, and related biological processes during ccRCC progression and evaluate their relevance to immunotherapy response and prognosis. We found that aggressive and metastatic ccRCC had higher proportions of genomic alterations, including SETD2 mutations, Del(14q), Del(9p), and higher immunosuppressive cellular and molecular infiltration levels. Of these, the Del(14q) might mediate immune escape in ccRCC via the VEGFA-VEGFR2 signaling pathway. Furthermore, immune-related pathways associated with ccRCC progression did not affect the immunotherapeutic response to ccRCC. Conversely, cell cycle pathways not only affected ccRCC progression and prognosis, but also were related to ccRCC immunotherapeutic response resistance. Overall, we described the immunogenomic characteristics of ccRCC progression and their correlations with immunotherapeutic response and prognosis, providing new insights into their prediction and the development of novel therapeutic strategies.

Kidney Cancer and Chronic Kidney Disease: Too Close for Comfort

Kidney cancer and chronic kidney disease are two renal pathologies with very different clinical management strategies and therapeutical options. Nonetheless, the cellular and molecular mechanisms underlying both conditions are closely related. Renal physiology is adapted to operate with a limited oxygen supply, making the kidney remarkably equipped to respond to hypoxia. This tightly regulated response mechanism is at the heart of kidney cancer, leading to the onset of malignant cellular phenotypes. Although elusive, the role of hypoxia in chronic kidney diseases is emerging as related to fibrosis, a pivotal factor in decaying renal function. The present review offers a perspective on the common biological traits shared between kidney cancer and chronic kidney disease and the available and prospective therapies for both conditions.

Cabozantinib plus immunotherapy combinations in metastatic renal cell and urothelial carcinoma

Treatment options for metastatic renal cell carcinoma (mRCC) and metastatic urothelial carcinoma (mUC) have increased dramatically over the past decade. However, even when novel approaches have proven to be effective as monotherapy, many patients still develop progressive disease, and different strategies are needed to increase clinical response and quality of life. Strategies combining targeted therapy (TT) and immunotherapy (IO) have emerged as a way to shorten the gap between responders and nonresponders to monotherapy and have reported promising results. In this review, we discuss the current role of cabozantinib in combination with IO agents in the treatment of metastatic RCC and UC and go over future directions in the field.

Gene signatures with therapeutic value: emerging perspective for personalized immunotherapy in renal cancer

Renal cancer is one of the deadliest urogenital diseases. In recent years, the advent of immunotherapy has led to significant improvement in the management of patients with renal cancer. Although cancer immunotherapy and its combinations had benefited numerous patients, several challenges need to be addressed. Apart from the high costs of treatment, the lack of predictive biomarkers and toxic side-effects have impeded its wider applicability. To address these issues, new biomarkers are required to predict responsiveness and design personalized treatment strategies. Recent advances in the field of single-cell sequencing and multi-dimensional spatial transcriptomics have identified clinically relevant subtypes of renal cancer. Furthermore, there is emerging potential for gene signatures based on immune cells, non-coding RNAs, and pathways such as metabolism and RNA modification. In this review article, we have discussed recent progress in the identification of gene signatures with predictive and prognostic potential in renal cancer.

mTOR Inhibition Increases Transcription Factor E3 (TFE3) Activity and Modulates Programmed Death-Ligand 1 (PD-L1) Expression in Translocation Renal Cell Carcinoma

The efficacy of programmed cell death protein ligand (PD-L)-1/PD-1 checkpoint blockade in renal cell carcinoma (RCC) remains unknown. The effects of mTOR inhibitors are uncertain, and patients may develop resistance to them. The limited understanding of cancer cell-intrinsic mTOR-mediated pathways remains a challenge in developing effective treatments. Whether transcription factor (TF)-E3 regulates PD-L1 expression and the tumor microenvironment was investigated, and the effects of an mammalian target of rapamycin (mTOR) inhibitor on translocation RCC were explored. TFE3 was overexpressed in clear cell RCC cell lines, and PD-L1 expression was analyzed by Western blot analysis. PD-L1 activity in relation to TFE3 expression in translocation RCC was also analyzed, via TFE3 knockdown and treatment with an mTOR inhibitor. The results were correlated with the gene expression profile, evaluated using digital multiplex analysis. TFE3 and PD-L1 expression were positively correlated in RCC cells. TFE3 overexpression was associated with the expression of PD-L1 in RCC. Furthermore, mTOR inhibition was associated with enhanced PD-L1 expression via TFE3 activation in translocation RCC. These data support the feasibility of combination therapy based on mTOR inhibition and PD-L1 blockade as a novel strategy for the treatment of patients with translocation RCC.

Renal cell carcinoma therapy: Current and new drug candidates

Renal cell carcinoma (RCC) is the most common and lethal tumor of the urological system. Curative treatment of localized RCC includes nephrectomy, radio-ablation, and active surveillance, whereas metastatic RCC (mRCC) requires a combination of surgery and systemic therapy. Response to conventional therapy is limited but, recently, many novel therapies for mRCC have emerged, including targeted therapies and new immunotherapeutic agents. Nevertheless, development of resistance and limited durable responses demand new anticancer candidates with improved selectivity and efficacy. In this review, we summarize recent preclinical studies of novel natural and synthetic compounds to treat RCC, detailing their mechanisms of action and anticancer activities.

PI3K/AKT/mTOR signalling pathway involvement in renal cell carcinoma pathogenesis (Review)

Renal cell carcinoma (RCC) accounts for over 90% of all renal malignancies, and mainly affects the male population. Obesity and smoking are involved in the pathogenesis of several systemic cancers including RCC. The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signalling pathway regulates cell growth, differentiation, migration, survival, angiogenesis, and metabolism. Growth factors, hormones, cytokine and many extracellular cues activate PI3K/AKT/mTOR. Dysregulation of this molecular pathway is frequently reported in human cancers including RCC and is associated with aggressive development and poor survival rate. mTOR is the master regulator of cell metabolism and growth, and is activated in many pathological processes such as tumour formation, insulin resistance and angiogenesis. mTOR inhibitors are used at present as drug therapy for RCC to inhibit cell proliferation, growth, survival, and the cell cycle. Temsirolimus and everolimus are two mTOR inhibitors that are currently used for the treatment of RCC. Drugs targeting the PI3K/AKT/mTOR signalling pathway may be one of the best therapeutic options for RCC.

Racially Disparate Expression of mTOR/ERK-1/2 Allied Proteins in Cancer

Recent studies revealed that ethnic differences in mechanistic target of rapamycin (mTOR) and extracellular signal-regulated kinase (ERK-1/2) signaling pathways might be associated with the development and progression of different human malignancies. The African American (AA) population has an increased rate of cancer incidence and mortality compared to the Caucasian American (CA) population. Although the socioeconomic differences across different ethnic groups contribute to the disparity in developing different cancers, recent scientific evidence indicates the association of molecular and genetic variations in racial disparities of different human malignancies. The mTOR and ERK-1/2 signaling pathways are one of the well-known oncogenic signaling mechanisms that regulate diverse molecular and phenotypic aspects of normal as well as cancer cells in response to different external or internal stimuli. To date, very few studies have been carried out to explore the significance of racial disparity with abnormal mTOR and ERK-1/2 kinase signaling pathways, which may contribute to the development of aggressive human cancers. In this review, we discuss the differential regulation of mTOR and ERK-1/2 kinase signaling pathways across different ethnic groups, especially between AA and CA populations. Notably, we observed that key signaling proteins associated with mTOR and ERK-1/2 pathway including transforming growth factor-beta (TGF-β), Akt, and VEGFR showed racially disparate expression in cancer patients. Overall, this review article encompasses the significance of racially disparate signaling molecules related to mTOR/ERK1/2 and their potential in developing tailor-made anti-cancer therapies.

The Therapeutic Landscape of Renal Cell Carcinoma: From the Dark Age to the Golden Age

Oncologic treatments for renal cell carcinoma (RCC) have undergone a major revolution in the past 2 decades, moving away from the pre-2004 Dark Age during which interleukin 2 and interferon-α were the only therapeutic options and induced treatment responses in only 5% to 10% of patients with metastatic disease. The development of anti-angiogenic tyrosine kinase inhibitors against vascular endothelial growth factor receptor 2 and inhibitors of mammalian target of rapamycin complex 1 in 2005 introduced the Modern Age with better overall and progression-free survival and a greater number of patients (30%-40%) responding to and (∼80%) benefiting from these targeted therapeutic agents. The coming of age of the immuno-oncology era with the use of immune checkpoint inhibitors (ICIs) have ushered us into the Golden Age of metastatic RCC care, in which combined administrations of two ICIs (anti-programmed cell death protein 1/programmed death-ligand 1 and anti-cytotoxic T-lymphocyte-associated protein 4 or one tyrosine kinase inhibitor plus one ICI (anti-programmed cell death protein 1/programmed death-ligand 1) have recast the treatment landscape of clear cell RCC, the most common RCC subtype, with an approximately 60% response rate and an approximately 90% disease control rate that further improves metastatic RCC survival. Exciting clinical trials are in the pipeline investigating complementary/synergistic molecular mechanisms, based on studies investigating the biology, pathology, and genomics of renal carcinoma and the respective treatment outcome. This will enable us to enter the Diamond Age of precision medicine in which a specific treatment can be tailored to the specific biological and pathologic circumstance of an individual kidney tumor to offer more effective yet less toxic therapy.

The Ambivalent Role of miRNAs in Carcinogenesis: Involvement in Renal Cell Carcinoma and Their Clinical Applications

The analysis of microRNA (miRNAs), small, non-coding endogenous RNA, plays a crucial role in oncology. These short regulatory sequences, acting on thousands of messenger RNAs (mRNAs), modulate gene expression at the transcriptional and post-transcriptional level leading to translational repression or degradation of target molecules. Although their function is required for several physiological processes, such as proliferation, apoptosis and cell differentiation, miRNAs are also responsible for development and/or progression of several cancers, since they may interact with classical tumor pathways. In this review, we highlight recent advances in deregulated miRNAs in cancer focusing on renal cell carcinoma (RCC) and provide an overview of the potential use of miRNA in their clinical settings, such as diagnostic and prognostic markers.

In vivo effects of olive oil and trans-fatty acids on miR-134, miR-132, miR-124-1, miR-9-3 and mTORC1 gene expression in a DMBA-treated mouse model

Both the intake of beneficial olive oil and of harmful trans-fatty acids (TFAs) in consumed foods are of great significance in tumor biology. In our present study we examined the effects they exert on the expression patterns of miR-134, miR-132, miR-124-1, miR-9-3 and mTOR in the liver, spleen and kidney of mice treated with 7,12-dimethylbenz [a] anthracene (DMBA). Feeding of TFA-containing diet significantly increased the expression of all studied miRs and mTORC1 in all organs examined, except the expression of mTORC1 in the spleen and kidney. Diet containing olive oil significantly reduced the expression of miR-124-1, miR-9-3 and mTORC1 in the liver and spleen. In the kidney, apart from the mTORC1 gene, the expression of all miRs examined significantly decreased compared to the DMBA control. According to our results, the cell membrane protective, antioxidant, and anti-inflammatory effects of olive oil and the cell membrane damaging, inflammatory, and carcinogenic properties of TFA suggest negative feedback regulatory mechanisms. In contrast to our expectations, mTORC1 gene expression in the kidney has not been shown to be an appropriate biomarker-presumably, because the many complex effects that regulate mTOR expression may quench each other.

Accuracy of Subclassification and Grading of Renal Tumors on Fine Needle Aspiration Cytology Alone

BACKGROUND

Fine needle aspiration (FNA) of renal masses can distinguish between benign and malignant neoplasms in 73-94% of cases. Previous studies suggested the correct subclassification of renal cell carcinomas (RCCs) by cytomorphology can be achieved in up to 80% of cases. However, as RCCs become increasingly subclassified by molecular signatures, correct subclassification based on cytology alone is increasingly difficult.

DESIGN

Two FNA passes (2 stained with Diff-Quik® and 2 with the Papanicolaou method) were performed on all fresh nephrectomy specimens for a 1-year period. There were 30 cases in this study, with 29 primary renal tumors and 1 case of metastatic lung adenocarcinoma. Each case was assigned a random number and came with 2 slides (1 from each staining method). Eight cytopathologists were asked to provide a diagnosis and the World Health Organization/International Society of Urological Pathology (WHO/ISUP) grading if applicable. Fleiss' Kappa and Cohen's Kappa equations were used to look at inter-rater variability.

RESULTS

When compared to the surgical pathology diagnosis, the average percent correct diagnosis for all cytopathologist was 35%. Chromophobe RCCs had the best average percent accuracy at 72% followed by clearcell RCC at 48%. Average accuracy for grading RCCs was 40%. Inter-rater variability among the cytopathologists for all RCC diagnoses was fair with a Fleiss' Kappa coefficient of 0.28. For the WHO/ISUP grade, the weighted coefficient for each pathologist ranged from 0.11 to 0.45, ranging from fair to moderate, respectively.

CONCLUSIONS

Renal tumors are difficult to classify on cytopathology alone. Core needle biopsy and ancillary studies are necessary if diagnosis will change management.

TSC/MTOR-mutated eosinophilic renal tumors are a distinct entity that is CK7+/CK20-/vimentin-: a validation study

Unclassified renal cell carcinoma (RCC) accounts for ∼10% of renal tumors, and the most common histologic finding in these cases is eosinophilic cytoplasm. We previously demonstrated that a subset of eosinophilic renal tumors with heterogeneous morphology and immunohistochemical (IHC) staining harbored pathogenic mutations in tuberous sclerosis complex (TSC) or mammalian target of rapamycin (MTOR) as the primary defining mutation. We identified an additional 8 cases of eosinophilic tumors with unusual morphology that were originally diagnosed as chromophobe RCC (CHRCC) or CHRCC, eosinophilic variant. As a comparison, we included four classic CHRCC cases and one CHRCC, eosinophilic variant case. Gross examination revealed solid or solid and cystic patterns. The solid areas were composed of eosinophilic tumor cells divided by congested vessels, whereas the cystic areas were lined by cytologically bland eosinophilic cells with septae containing nests, ribbons, and single eosinophilic tumor cells. The tumor cells had abundant granular eosinophilic cytoplasm with round nuclei and inconspicuous nucleoli. IHC analysis demonstrated diffuse staining for CK7 and negative staining for CK20 and vimentin. Next-generation sequencing identified pathogenic variants in three genes: TSC1, TSC2, and MTOR. They also lacked significant copy number variations in contrast to our control cases. We have demonstrated with our expanded study that cases previously diagnosed as CHRCC or CHRCC, eosinophilic variant with discordant histology and IHC staining patterns may represent a separate subtype of RCC characterized by mutations in the TSC/MTOR pathway.

The Pan-Omics Landscape of Renal Cell Carcinoma and Its Implication on Future Clinical Practice

Renal cell carcinoma has traditionally been classified based on histological features. Contemporary studies have identified genomic, transcriptomic, epigenomic, and metabolomic signatures that correspond to or even transcend histological subtypes. Much remains to be learned about improving the algorithm of pan-omics integration for precision oncology, which will not only advance our understanding of RCC pathobiology and treatment response but also result in novel therapeutic opportunities. Accordingly, this review focuses on recent RCC multi-omics literature. Encouragingly, a few reports on omics integration into routinely employed prognostic risk models have shown early promise that could lay the foundation for future development of precision kidney cancer therapies. Hence, this article serves as a primer on what we have learned and how we might better realize the clinical potential of the burgeoning pan-omics data.

Renal Cell Tumors: Uncovering the Biomarker Potential of ncRNAs

Renal cell tumors (RCT) remain as one of the most common and lethal urological tumors worldwide. Discrimination between (1) benign and malignant disease, (2) indolent and aggressive tumors, and (3) patient responsiveness to a specific therapy is of major clinical importance, allowing for a more efficient patient management. Nonetheless, currently available tools provide limited information and novel strategies are needed. Over the years, a putative role of non-coding RNAs (ncRNAs) as disease biomarkers has gained relevance and is now one of the most prolific fields in biological sciences. Herein, we extensively sought the most significant reports on ncRNAs as potential RCTs' diagnostic, prognostic, predictive, and monitoring biomarkers. We could conclude that ncRNAs, either alone or in combination with currently used clinical and pathological parameters, might represent key elements to improve patient management, potentiating the implementation of precision medicine. Nevertheless, most ncRNA biomarkers require large-scale validation studies, prior to clinical implementation.

Next-generation RNA Sequencing-based Biomarker Characterization of Chromophobe Renal Cell Carcinoma and Related Oncocytic Neoplasms

BACKGROUND

Renal cell carcinomas (RCCs) are a heterogeneous group of neoplasms. Recent sequencing studies revealed various molecular features associated with histologic RCC subtypes, including chromophobe renal cell carcinoma (ChRCC).

OBJECTIVE

To characterize the gene expression and biomarker signatures associated with ChRCC.

DESIGN, SETTING, AND PARTICIPANTS

We performed integrative analysis on RNA sequencing data available from 1049 RCC specimens from The Cancer Genome Atlas and in-house studies. Our workflow identified genes relatively enriched in ChRCC, including Forkhead box I1 (FOXI1), Rh family C glycoprotein (RHCG), and LINC01187. We assessed the expression pattern of FOXI1 and RHCG protein by immunohistochemistry (IHC) and LINC01187 mRNA by RNA in situ hybridization (RNA-ISH) in whole tissue sections representing a cohort of 197 RCC cases, including both primary and metastatic tumors.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The FOXI1 and RHCG IHC staining, as well as the LINC01187 RNA-ISH staining, was evaluated in each case for intensity, pattern, and localization of expression.

RESULTS AND LIMITATIONS

All primary and metastatic classic ChRCCs demonstrated homogeneous positive labeling for FOXI1, RHCG proteins, and LINC01187 transcript. Unclassified RCC with oncocytic features, oncocytoma, and hybrid oncocytic tumor, as well as all but two cases of eosinophilic ChRCC also stained positive. Importantly, metastatic and primary RCC of all other subtypes did not demonstrate any unequivocal staining for FOXI1, RHCG, or LINC01187. In normal kidney, FOXI1, RHCG, and LINC01187 were detected in the distal nephron segment, specifically in intercalated cells. Two cases of eosinophilic ChRCC with focal expression of FOXI1 and LINC01187, and Golgi-like RHCG staining were found to contain MTOR gene mutations upon DNA sequencing.

CONCLUSIONS

We demonstrate a pipeline for the identification and validation of RCC subtype-specific biomarkers that can aid in the confirmation of cell of origin and may facilitate accurate classification and diagnosis of renal tumors.

PATIENT SUMMARY

FOXI1, RHCG, and LINC01187 are lineage-specific signature genes for chromophobe renal cell carcinoma.

KLF4K409Q-mutated meningiomas show enhanced hypoxia signaling and respond to mTORC1 inhibitor treatment

Meningioma represents the most common primary brain tumor in adults. Recently several non-NF2 mutations in meningioma have been identified and correlated with certain pathological subtypes, locations and clinical observations. Alterations of cellular pathways due to these mutations, however, have largely remained elusive. Here we report that the Krueppel like factor 4 (KLF4)-K409Q mutation in skull base meningiomas triggers a distinct tumor phenotype. Transcriptomic analysis of 17 meningioma samples revealed that KLF4^K409Q mutated tumors harbor an upregulation of hypoxia dependent pathways. Detailed in vitro investigation further showed that the KLF4^K409Q mutation induces HIF-1α through the reduction of prolyl hydroxylase activity and causes an upregulation of downstream HIF-1α targets. Finally, we demonstrate that KLF4^K409Q mutated tumors are susceptible to mTOR inhibition by Temsirolimus. Taken together, our data link the KLF4^K409Q mediated upregulation of HIF pathways to the clinical and biological characteristics of these skull base meningiomas possibly opening new therapeutic avenues for this distinct meningioma subtype.

Phase I study of the mTOR inhibitor everolimus in combination with the histone deacetylase inhibitor panobinostat in patients with advanced clear cell renal cell carcinoma

Background Preclinical studies suggested synergistic anti-tumor activity when pairing mTOR inhibitors with histone deacetylase (HDAC) inhibitors. We completed a phase I, dose-finding trial for the mTOR inhibitor everolimus combined with the HDAC inhibitor panobinostat in advanced clear cell renal cell carcinoma (ccRCC) patients. We additionally investigated expression of microRNA 605 (miR-605) in serum samples obtained from trial participants. Patients and Methods Twenty-one patients completed our single institution, non-randomized, open-label, dose-escalation phase 1 trial. miR-605 levels were measured at cycle 1/day 1 (C1D1) and C2D1. Delta Ct method was utilized to evaluate miR-605 expression using U6B as an endogenous control. Results There were 3 dosing-limiting toxicities (DLTs): grade 4 thrombocytopenia (n = 1), grade 3 thrombocytopenia (n = 1), and grade 3 neutropenia (n = 1). Everolimus 5 mg PO daily and panobinostat 10 mg PO 3 times weekly (weeks 1 and 2) given in 21-day cycles was the recommended phase II dosing based on their maximum tolerated dose. The 6-month progression-free survival was 31% with a median of 4.1 months (95% confidence internal; 2.0-7.1). There was higher baseline expression of miR-605 in patients with progressive disease (PD) vs those with stable disease (SD) (p = 0.0112). PD patients' miR-605 levels decreased after the 1st cycle (p = 0.0245), whereas SD patients' miR-605 levels increased (p = 0.0179). Conclusion A safe and tolerable dosing regimen was established for combination everolimus/panobinostat therapy with myelosuppression as the major DLT. This therapeutic pairing did not appear to improve clinical outcomes in our group of patients with advanced ccRCC. There was differential expression of miR-605 that correlated with treatment response. Clinical trial information: NCT01582009.

Phase I study of ipatasertib as a single agent and in combination with abiraterone plus prednisolone in Japanese patients with advanced solid tumors

PURPOSE

Ipatasertib is a selective inhibitor of Akt, a frequently activated protein kinase in human cancers. The current study assessed the safety, tolerability, and pharmacokinetics of ipatasertib in Japanese patients with solid tumors.

METHODS

This was a phase I, open-label, 3 + 3 dose-escalation study conducted in two stages. In stage I, Japanese patients with solid tumors were administered ipatasertib 200, 400, or 600 mg/day for 21 days of a 28-day cycle. In stage II, Japanese patients with castration-resistant prostate cancer were administered ipatasertib 200 or 400 mg/day in combination with abiraterone and prednisolone in 28-day cycles. Dose-limiting toxicity (DLT) was assessed at each dose before enrolling patients at a higher dose; DLT was used to determine the maximum tolerated dose (MTD) and maximum administered dose (MAD). Pharmacokinetic parameters were assessed after a single dose and at steady state.

RESULTS

Fifteen patients were enrolled in Stage I and six in Stage II. The ipatasertib MTD was 600 mg as monotherapy and MAD was 400 mg in combination with abiraterone and prednisolone. Ipatasertib plasma exposure was dose proportional across the dose range, and was not markedly affected by concurrent administration of abiraterone plus prednisolone. Stable disease (SD) was observed in eight patients treated with ipatasertib monotherapy (53.3%); four patients had SD and one had complete response with ipatasertib plus abiraterone and prednisolone.

CONCLUSIONS

Ipatasertib, at the monotherapy MTD of 600 mg/day and MAD of 400 mg/day in combination with abiraterone and prednisolone, was safe and tolerable in Japanese patients with solid tumors.

The Codon 72 TP53 Polymorphism Contributes to TSC Tumorigenesis through the Notch-Nodal Axis

We discovered that 90.3% of patients with angiomyolipomas, lymphangioleiomyomatosis (LAM), and tuberous sclerosis complex (TSC) carry the arginine variant of codon 72 (R72) of TP53 and that R72 increases the risk for angiomyolipoma. R72 transactivates NOTCH1 and NODAL better than the proline variant of codon 72 (P72); therefore, the expression of NOTCH1 and NODAL is increased in angiomyolipoma cells that carry R72. The loss of Tp53 and Tsc1 within nestin-expressing cells in mice resulted in the development of renal cell carcinomas (RCC) with high Notch1 and Nodal expression, suggesting that similar downstream mechanisms contribute to tumorigenesis as a result of p53 loss in mice and p53 polymorphism in humans. The loss of murine Tp53 or expression of human R72 contributes to tumorigenesis via enhancing epithelial-to-mesenchymal transition and motility of tumor cells through the Notch and Nodal pathways. IMPLICATIONS: This work revealed unexpected contributions of the p53 polymorphism to the pathogenesis of TSC and established signaling alterations caused by this polymorphism as a target for therapy. We found that the codon 72 TP53 polymorphism contributes to TSC-associated tumorigenesis via Notch and Nodal signaling.

mTOR inhibitor and bone-targeted drugs break the vicious cycle between clear-cell renal carcinoma and osteoclasts in an in vitro co-culture model

The skeleton is one of the most common sites of metastatic spread from advanced clear-cell renal carcinoma (ccRCC). Most of the bone lesions observed in RCC patients are classified as osteolytic, causing severe pain and morbidity due to pathological bone destruction. Nowadays, it is well known that cancer induced bone loss in lytic metastasis is caused by the triggering of a vicious cycle between cancer and bone resident cells that leads to an imbalance between bone formation and degradation. Targeting the mammalian target of rapamycin (mTOR) is an efficient treatment option for metastatic renal carcinoma patients. Moreover, bone targeted therapy could benefit bone metastatic cancer patients caused by advanced RCC. However, more data is needed to support the hypothesis of the beneficial effect of a combined therapy. The aim of this work is to investigate the effect of targeting mTOR and the sequential combination with bone targeted therapy as a strategy to break the vicious cycle between ccRCC cells and osteoclasts. A previously optimized fully human co-culture model is used to mimic the crosstalk between Caki-2 cells (ccRCC) and osteoclasts. Cells are treated at fixed timing with everolimus, zoledronic acid and denosumab as single or sequential combined treatment. We show that Caki-2 cells can induce osteoclast cells differentiation from isolated human monocytes, as demonstrated by specific tartrate-resistant acid phosphatase (TRAP) staining and f-actin ring formation, in a statistically significant manner. Moreover, differentiated osteoclasts proved to be functionally active by pit formation assay. Caki-2 cells co-cultured with osteoclasts acquire a more aggressive phenotype based on gene expression analysis. Interestingly, the sequential combined treatment of everolimus and zoledronic acid is the most effective in the inhibition of both Caki-2 cells survival and osteoclastogenic potential, making it an effective strategy to inhibit the vicious cycle of bone metastasis. At preclinical level, this observation confirms the value of our co-culture model as a useful tool to mimic the bone microenvironment and to assess drug sensitivity in vitro. A better understanding of the molecular mechanisms involved in tumor-bone cells crosstalk will be investigated next.

Best treatment options for advanced renal cell carcinoma (RCC) patients: a Delphi consensus study

The introduction of targeted therapy for the treatment of advanced renal cell carcinoma (RCC) has improved the outcome of these patients in the last decade. However, many patients still relapse. The aim of this consensus study was to establish common recommendations about the best treatment options in patients with RCC. A two-round Delphi methodology was used. A total of 25 statements were submitted to a panel of 30 specialists. If consensus was not obtained in the first round a second and last round was performed. Agreement was achieved for 19 of the proposed 25 statements (76%). When making a decision about the treatment option, considering the efficiency and response rate to previous treatment, drug's toxicity and the patients' clinical features are very relevant.

Effect of Everolimus on Heterogenous Renal Cancer Cells Populations Including Renal Cancer Stem Cells

The aim of this study was to compare effect of everolimus on growth of different renal cell carcinoma (RCC) populations and develop experimental design to measure the early response of everolimus in clear cell RCC (ccRCC) cell lines including renal cancer stem cells. Effect of everolimus on RCC cell lines which include primary (786-0) and metastatic (ACHN) RCC cell lines as well as heterogenous populations of tumor cells of different histological RCC subtypes (clear cell RCC and papillary RCC) was measured when treated with everolimus in the range of 1-9 µM. Gene expression profiling using microarray was performed to determine the early response to everolimus in ccRCC cell lines after optimizing concentration of drug. Gene Set Enrichment Analysis (GSEA) was done which mainly focused on basic genes related to mTOR, hormonal and metabolic pathways. Everolimus acts on RCC cells in a dose-dependent manner. In all examined cell lines IC50 dose was possible to calculate after the third day of treatment. In ccRCC lines (parental and stem cell) everolimus changes expression of mTOR complexes elements and elements of related pathways when treated with optimized doses of drug. Characteristic expression profile for ccRCC cells at an early exposure time to everolimus is to elucidate. Wevarie include some basic observations derived from data analysis in the context of mechanism of action of drug with a view to better understand biology of renal cancer cells.

Therapeutic Targeting of TFE3/IRS-1/PI3K/mTOR Axis in Translocation Renal Cell Carcinoma

PURPOSE

Translocation renal cell carcinoma (tRCC) represents a rare subtype of kidney cancer associated with various TFE3, TFEB, or MITF gene fusions that are not responsive to standard treatments for RCC. Therefore, the identification of new therapeutic targets represents an unmet need for this disease.

EXPERIMENTAL DESIGN

We have established and characterized a tRCC patient-derived xenograft, RP-R07, as a novel preclinical model for drug development by using next-generation sequencing and bioinformatics analysis. We then assessed the therapeutic potential of inhibiting the identified pathway using in vitro and in vivo models.

RESULTS

The presence of a SFPQ-TFE3 fusion [t(X;1) (p11.2; p34)] with chromosomal break-points was identified by RNA-seq and validated by RT-PCR. TFE3 chromatin immunoprecipitation followed by deep sequencing analysis indicated a strong enrichment for the PI3K/AKT/mTOR pathway. Consistently, miRNA microarray analysis also identified PI3K/AKT/mTOR as a highly enriched pathway in RP-R07. Upregulation of PI3/AKT/mTOR pathway in additional TFE3-tRCC models was confirmed by significantly higher expression of phospho-S6 (P < 0.0001) and phospho-4EBP1 (P < 0.0001) in established tRCC cell lines compared with clear cell RCC cells. Simultaneous vertical targeting of both PI3K/AKT and mTOR axis provided a greater antiproliferative effect both in vitro (P < 0.0001) and in vivo (P < 0.01) compared with single-node inhibition. Knockdown of TFE3 in RP-R07 resulted in decreased expression of IRS-1 and inhibited cell proliferation.

CONCLUSIONS

These results identify TFE3/IRS-1/PI3K/AKT/mTOR as a potential dysregulated pathway in TFE3-tRCC, and suggest a therapeutic potential of vertical inhibition of this axis by using a dual PI3K/mTOR inhibitor for patients with TFE3-tRCC.

Cyclopeptide RA-V Inhibits Organ Enlargement and Tumorigenesis Induced by YAP Activation

The Hippo pathway restricts organ size during development and its inactivation plays a crucial role in cancer. Yes-associated protein (YAP) and its paralog transcriptional coactivator with PSD-95/Dlg/ZO-1 (PDZ)-binding motif (TAZ) are transcription co-activators and effectors of the Hippo pathway mediating aberrant enlargement of organs and tumor growth upon Hippo pathway inactivation. It has been demonstrated that genetic inactivation of YAP could be an effective approach to inhibit tumorigenesis. In order to identify pharmacological inhibitors of YAP, we screened a library of 52,683 compounds using a YAP-specific reporter assay. In this screen we identified cyclopeptide RA-V (deoxybouvardin) as a specific inhibitor of YAP and TAZ but not other reporters. Unexpectedly, later experiments demonstrated that RA-V represses the protein but not mRNA levels of YAP target genes. Nevertheless, RA-V strongly blocks liver enlargement induced by Mst1/2 knockout. Furthermore, RA-V not only inhibits liver tumorigenesis induced by YAP activation, but also induces regression of established tumors. We found that RA-V inhibits dedifferentiation and proliferation, while inducing apoptosis of hepatocytes. Furthermore, RA-V also induces apoptosis and inhibits proliferation of macrophages in the microenvironment, which are essential for YAP-induced tumorigenesis. RA-V is thus a drug candidate for cancers involving YAP/TAZ activation.

Preclinical evidence of the enhanced effectiveness of combined rapamycin and AICAR in reducing kidney cancer

Loss of Von Hippel-Lindau in renal carcinoma cells results in upregulation of the activity of hypoxia-inducible factor (HIF-α), a major transcription factor involved in kidney cancer. Rapamycin as mammalian target of rapamycin inhibitor and 5-aminoimidazole-4-carboxamide-riboside (AICAR) as AMPK activator are used separately to treat cancer patients. In the current study, the possible additive effect of drug combinations in reducing kidney tumorigenesis was investigated. Treatment with drug combinations significantly decreased cell proliferation, increased cell apoptosis, and abolished Akt phosphorylation and HIF-2α expression in renal cell carcinoma cells, including primary cells isolated from kidney cancer patients. Significant decreases in cell migration and invasion were detected using drug combinations. Drug combinations effectively abolished binding of HIF-2α to the Akt promoter and effected formation of the DNA-protein complex in nuclear extracts from 786-O cells, as demonstrated using electromobility shift assay and examination of Akt promoter activity. Importantly, we tested the effect of each drug and the combined drugs on kidney tumor size in the nude mouse model. Our data show that treatment with rapamycin, AICAR, and rapamycin+AICAR decreased tumor size by 38%, 36%, and 80%, respectively, suggesting that drug combinations have an additive effect in reducing tumor size compared with use of each drug alone. Drug combinations effectively decreased cell proliferation, increased apoptotic cells, and significantly decreased p-Akt, HIF-2α, and vascular endothelial growth factor expression in tumor kidney tissues from mice. These results show for the first time that drug combinations are more effective than single drugs in reducing kidney tumor progression. This study provides important evidence that may lead to the initiation of pre-clinical trials in patients with kidney cancer.

Cabozantinib for the Management of Metastatic Clear Cell Renal Cell Carcinoma

Cabozantinib is a multi-tyrosine kinase inhibitor used for the treatment of various solid-organ tumours. It was recently approved as a first- and second-line therapeutic for the management of advanced/metastatic renal cell carcinoma based on the results of two randomised controlled trials. The phase III METEOR trial compared cabozantinib against everolimus as a second- or greater line therapy and found benefits in progression-free and overall survival, and the phase II CABOSUN trial compared cabozantinib against sunitinib as a first-line therapeutic and found benefits in terms of progression-free survival. This review briefly summarises how cabozantinib fits into current treatment paradigms for the management of advanced renal cell carcinoma.