Efficacy and Safety of Telaglenastat Plus Cabozantinib vs Placebo Plus Cabozantinib in Patients With Advanced Renal Cell Carcinoma: The CANTATA Randomized Clinical Trial

Immunotherapy resistance in solid tumors: mechanisms and potential solutions

While the emergence of immunotherapies has fundamentally altered the management of solid tumors, cancers exploit many complex biological mechanisms that result in resistance to these agents. These encompass a broad range of cellular activities - from modification of traditional paradigms of immunity via antigen presentation and immunoregulation to metabolic modifications and manipulation of the tumor microenvironment. Intervening on these intricate processes may provide clinical benefit in patients with solid tumors by overcoming resistance to immunotherapies, which is why it has become an area of tremendous research interest with practice-changing implications. This review details the major ways cancers avoid both natural immunity and immunotherapies through primary (innate) and secondary (acquired) mechanisms of resistance, and it considers available and emerging therapeutic approaches to overcoming immunotherapy resistance.

Mitochondrial metabolism: A moving target in hepatocellular carcinoma therapy

Mitochondria are pivotal contributors to cancer mechanisms due to their homeostatic and pathological roles in cellular bioenergetics, biosynthesis, metabolism, signaling, and survival. During transformation and tumor initiation, mitochondrial function is often disrupted by oncogenic mutations, leading to a metabolic profile distinct from precursor cells. In this review, we focus on hepatocellular carcinoma, a cancer arising from metabolically robust and nutrient rich hepatocytes, and discuss the mechanistic impact of altered metabolism in this setting. We provide distinctions between normal mitochondrial activity versus disease-related function which yielded therapeutic opportunities, along with highlighting recent preclinical and clinical efforts focused on targeting mitochondrial metabolism. Finally, several novel strategies for exploiting mitochondrial programs to eliminate hepatocellular carcinoma cells in metabolism-specific contexts are presented to integrate these concepts and gain foresight into the future of mitochondria-focused therapeutics.

Effectiveness of Second-Line Cabozantinib in Metastatic Clear Cell Renal Cell Carcinoma Patients After First-Line Treatment with Immune Checkpoint Inhibitor-based Combinations

Background

Cabozantinib, a tyrosine kinase inhibitor (TKI), is a prevalent second-line (2 L) therapy and was approved for use after progression on TKIs. However, the 1 L treatment setting has changed since the approval of cabozantinib monotherapy in salvage therapy settings.

Objective

To assess the differential effectiveness of cabozantinib after prior progression on 1 L ipilimumab with nivolumab (IPI + NIVO) compared to programmed death receptor-1 (PD-1) or PD-1 ligand (PD-L1) inhibitors (PD1/L1i) with TKIs.

Methods

Utilizing a nationwide electronic health record (EHR)-derived de-identified database, we included patients with metastatic clear cell renal cell carcinoma (mccRCC) who received 1 L treatment with an immune checkpoint inhibitor (ICI)-based combination and 2 L treatment with cabozantinib monotherapy. These patients were categorized based on the type of 1 L ICI-based combination received: IPI + NIVO vs. PD1/L1i with TKI. Real-world time to next therapy (rwTTNT) and real-world overall survival (rwOS) were summarized using Kaplan-Meier curves and compared using Cox-proportional hazard models adjusted for International mRCC Database Consortium (IMDC) risk groups.

Results

Among 12,285 patients with metastatic renal cell carcinoma, 237 were eligible and included. Median rwTTNT was 8 months for the IPI + NIVO subgroup and 7.5 months for the PD1/L1i + TKI subgroup (HR 1.05, 95% CI: 0.74-1.49, p = 0.8). Median rwOS was 17 months for IPI + NIVO and 16 months for PD1/L1i + TKI subgroup (HR 0.79, 95% CI: 0.52-1.20, p = 0.3).

Conclusions

Cabozantinib remains effective as a 2 L therapy for mccRCC independent of the type of prior 1 L ICI-based combination. Further research is needed to validate these findings and explore the ideal sequencing of therapies.

Cancer cell metabolism and antitumour immunity

Accumulating evidence suggests that metabolic rewiring in malignant cells supports tumour progression not only by providing cancer cells with increased proliferative potential and an improved ability to adapt to adverse microenvironmental conditions but also by favouring the evasion of natural and therapy-driven antitumour immune responses. Here, we review cancer cell-intrinsic and cancer cell-extrinsic mechanisms through which alterations of metabolism in malignant cells interfere with innate and adaptive immune functions in support of accelerated disease progression. Further, we discuss the potential of targeting such alterations to enhance anticancer immunity for therapeutic purposes.

Therapeutic implications of the metabolic changes associated with BRAF inhibition in melanoma

Melanoma metabolism can be reprogrammed by activating BRAF mutations. These mutations are present in up to 50% of cutaneous melanomas, with the most common being V600E. BRAF mutations augment glycolysis to promote macromolecular synthesis and proliferation. Prior to the development of targeted anti-BRAF therapies, these mutations were associated with accelerated clinical disease in the metastatic setting. Combination BRAF and MEK inhibition is a first line treatment option for locally advanced or metastatic melanoma harboring targetable BRAF mutations. This therapy shows excellent response rates but these responses are not durable, with almost all patients developing resistance. When BRAF mutated melanoma cells are inhibited with targeted therapies the metabolism of those cells also changes. These cells rely less on glycolysis for energy production, and instead shift to a mitochondrial phenotype with upregulated TCA cycle activity and oxidative phosphorylation. An increased dependence on glutamine utilization is exhibited to support TCA cycle substrates in this metabolic rewiring of BRAF mutated melanoma. Herein we describe the relevant core metabolic pathways modulated by BRAF inhibition. These adaptive pathways represent vulnerabilities that could be targeted to overcome resistance to BRAF inhibitors. This review evaluates current and future therapeutic strategies that target metabolic reprogramming in melanoma cells, particularly in response to BRAF inhibition.

Aerobic glycolysis but not GLS1-dependent glutamine metabolism is critical for anti-tumor immunity and response to checkpoint inhibition

Tumor cells undergo uncontrolled proliferation driven by enhanced anabolic metabolism including glycolysis and glutaminolysis. Targeting these pathways to inhibit cancer growth is a strategy for cancer treatment. Critically, however, tumor-responsive T cells share metabolic features with cancer cells, making them susceptible to these treatments as well. Here, we assess the impact on anti-tumor T cell immunity and T cell exhaustion by genetic ablation of lactate dehydrogenase A (LDHA) and glutaminase1 (GLS1), key enzymes in aerobic glycolysis and glutaminolysis. Loss of LDHA severely impairs expansion of T cells in response to tumors and chronic infection. In contrast, T cells lacking GLS1 can compensate for impaired glutaminolysis by engaging alternative pathways, including upregulation of asparagine synthetase, and thus efficiently respond to tumor challenge and chronic infection as well as immune checkpoint blockade. Targeting GLS1-dependent glutaminolysis, but not aerobic glycolysis, may therefore be a successful strategy in cancer treatment, particularly in combination with immunotherapy.

Contemporary Management of Renal Cell Carcinoma: A Review for General Practitioners in Oncology

Renal cell carcinoma accounts for a significant proportion of cancer diagnoses in Canadians. Over the past several years, the management of renal cell cancers has undergone rapid changes in all prognostic risk categories, resulting in improved oncologic outcomes. Novel strategies for metastatic disease make use of the synergy between checkpoints and angiogenesis inhibition. Moreover, combination checkpoint inhibition has demonstrated durable efficacy in some patients. Adjuvant immunotherapy has recently shown a survival benefit for the first time in select cases. Significant efforts are underway to explore new compounds or combinations for later-line diseases, such as inhibitors of hypoxia-inducible factors and radiolabeled biomolecules targeting tumor antigens within the neoplastic microenvironment for precise payload delivery. In this manuscript, we provide a comprehensive review of the available data addressing key therapeutic areas pertaining to systemic therapy for metastatic and localized disease, review the most relevant prognostic tools, describe local therapies and management of CNS disease, and discuss practice-changing trials currently underway. Finally, we focus on some of the practical aspects for general practitioners in oncology caring for patients with renal cell carcinoma.

Glutamine Metabolism and Prostate Cancer

Glutamine (Gln) is a non-essential amino acid that is involved in the development and progression of several malignancies, including prostate cancer (PCa). While Gln is non-essential for non-malignant prostate epithelial cells, PCa cells become highly dependent on an exogenous source of Gln. The Gln metabolism in PCa is tightly controlled by well-described oncogenes such as MYC, AR, and mTOR. These oncogenes contribute to therapy resistance and progression to the aggressive castration-resistant PCa. Inhibition of Gln catabolism impedes PCa growth, survival, and tumor-initiating potential while sensitizing the cells to radiotherapy. Therefore, given its significant role in tumor growth, targeting Gln metabolism is a promising approach for developing new therapeutic strategies. Ongoing clinical trials evaluate the safety and efficacy of Gln catabolism inhibitors in combination with conventional and targeted therapies in patients with various solid tumors, including PCa. Further understanding of how PCa cells metabolically interact with their microenvironment will facilitate the clinical translation of Gln inhibitors and help improve therapeutic outcomes. This review focuses on the role of Gln in PCa progression and therapy resistance and provides insights into current clinical trials.

Targeting amino acid-metabolizing enzymes for cancer immunotherapy

Despite the immune system's role in the detection and eradication of abnormal cells, cancer cells often evade elimination by exploitation of various immune escape mechanisms. Among these mechanisms is the ability of cancer cells to upregulate amino acid-metabolizing enzymes, or to induce these enzymes in tumor-infiltrating immunosuppressive cells. Amino acids are fundamental cellular nutrients required for a variety of physiological processes, and their inadequacy can severely impact immune cell function. Amino acid-derived metabolites can additionally dampen the anti-tumor immune response by means of their immunosuppressive activities, whilst some can also promote tumor growth directly. Based on their evident role in tumor immune escape, the amino acid-metabolizing enzymes glutaminase 1 (GLS1), arginase 1 (ARG1), inducible nitric oxide synthase (iNOS), indoleamine 2,3-dioxygenase 1 (IDO1), tryptophan 2,3-dioxygenase (TDO) and interleukin 4 induced 1 (IL4I1) each serve as a promising target for immunotherapeutic intervention. This review summarizes and discusses the involvement of these enzymes in cancer, their effect on the anti-tumor immune response and the recent progress made in the preclinical and clinical evaluation of inhibitors targeting these enzymes.

Cyclic fasting-mimicking diet in cancer treatment: Preclinical and clinical evidence

In preclinical tumor models, cyclic fasting and fasting-mimicking diets (FMDs) produce antitumor effects that become synergistic when combined with a wide range of standard anticancer treatments while protecting normal tissues from treatment-induced adverse events. More recently, results of phase 1/2 clinical trials showed that cyclic FMD is safe, feasible, and associated with positive metabolic and immunomodulatory effects in patients with different tumor types, thus paving the way for larger clinical trials to investigate FMD anticancer activity in different clinical contexts. Here, we review the tumor-cell-autonomous and immune-system-mediated mechanisms of fasting/FMD antitumor effects, and we critically discuss new metabolic interventions that could synergize with nutrient starvation to boost its anticancer activity and prevent or reverse tumor resistance while minimizing toxicity to patients. Finally, we highlight potential future applications of FMD approaches in combination with standard anticancer strategies as well as strategies to implement the design and conduction of clinical trials.

Renal cell carcinoma

The landscape of the management of renal cell carcinoma has evolved substantially in the last decade, leading to improved survival in localised and advanced disease. We review the epidemiology, pathology, and diagnosis of renal cell carcinoma and discuss the evidence for current management strategies from localised to metastatic disease. Developments in adjuvant therapies are discussed, including use of pembrolizumab-the first therapy to achieve overall survival benefit in the adjuvant setting. The treatment of advanced disease, including landmark trials that have established immune checkpoint inhibition as a standard of care, are also reviewed. We also discuss the current controversies that exist surrounding the management of metastatic renal cell carcinoma, including the use of risk assessment models for disease stratification and treatment selection for frontline therapy. Management of non-clear cell renal cell carcinoma subtypes is also reviewed. Future directions of research, including a discussion of ongoing clinical trials and the need for reliable biomarkers to guide treatment in kidney cancer, are also highlighted.

Harnessing the tumor microenvironment to boost adoptive T cell therapy with engineered lymphocytes for solid tumors

Adoptive cell therapy (ACT) using Chimeric Antigen Receptor (CAR) and T Cell Receptor (TCR) engineered T cells represents an innovative therapeutic approach for the treatment of hematological malignancies, yet its application for solid tumors is still suboptimal. The tumor microenvironment (TME) places several challenges to overcome for a satisfactory therapeutic effect, such as physical barriers (fibrotic capsule and stroma), and inhibitory signals impeding T cell function. Some of these obstacles can be faced by combining ACT with other anti-tumor approaches, such as chemo/radiotherapy and checkpoint inhibitors. On the other hand, cutting edge technological tools offer the opportunity to overcome and, in some cases, take advantage of TME intrinsic characteristics to boost ACT efficacy. These include: the exploitation of chemokine gradients and integrin expression for preferential T-cell homing and extravasation; metabolic changes that have direct or indirect effects on TCR-T and CAR-T cells by increasing antigen presentation and reshaping T cell phenotype; introduction of additional synthetic receptors on TCR-T and CAR-T cells with the aim of increasing T cells survival and fitness.

Efficacy, Safety, and Tolerability of Tivozanib in Heavily Pretreated Patients With Advanced Clear Cell Renal Cell Carcinoma

BACKGROUND

Tivozanib has been approved as a third-line or later therapy for advanced renal cell carcinoma based on the TIVO-3 trial, which was conducted before immune checkpoint therapies (ICT), cabozantinib, and lenvatinib/everolimus became incorporated in the current sequential treatment paradigm for advanced clear cell RCC (ccRCC).

METHODS

We performed a retrospective study of patients with advanced ccRCC treated with tivozanib at MD Anderson Cancer Center during 6/2021-7/2023. A blinded radiologist assessed tumor response by RECIST v1.1. We assessed overall response rate (ORR), clinical benefit rate (CBR) [percentage of all treated patients who achieved radiologic response or stable disease (SD) for ≥ 6 months], progression-free survival (PFS), overall survival (OS), and safety.

RESULTS

Of 30 analyzed patients, 23% had performance status ≥ 2; 47% had International Metastatic RCC Database Consortium (IMDC) poor-risk disease. Median number of prior therapies was 4 (range 1-8). All patients received prior ICT, 87% cabozantinib and 60% lenvatinib ± everolimus. Of 26 evaluable patients, 2 patients had confirmed partial response (ORR 7.7%); 5 patients had SD for ≥ 6 months (CBR 23.3%). Median PFS was 3.8 months (range 0.7-13.9); median OS was 14.1 months (range 0.3-28.5). Fifteen patients (50%) had ≥ 1 treatment-related adverse event (TRAE). There were 6 grade ≥ 3 TRAEs [hypertension, congestive heart failure (3), mucositis, and GI perforation (grade 5)].

CONCLUSIONS

In this cohort of heavily pretreated patients with advanced ccRCC, tivozanib yielded a modest clinical benefit in a minority of patients who received prior ICT, cabozantinib, and lenvatinib ± everolimus. TRAEs were consistent with previously published reports.

Targeting metabolic pathways to counter cancer immunotherapy resistance

Immunotherapies have revolutionized the treatment of certain cancers, but challenges remain in overcoming immunotherapy resistance. Research shows that metabolic modulation of the tumor microenvironment can enhance antitumor immunity. Here, we discuss recent preclinical and clinical evidence for the efficacy of combining metabolic modifiers with immunotherapies. While this combination holds great promise, a few key areas must be addressed, which include identifying the effects of metabolic modifiers on immune cell metabolism, the putative biomarkers of therapeutic efficacy, the efficacy of modifiers on tumors harboring metabolic heterogeneity, and the potential development of resistance due to tumor reliance on alternative metabolic pathways. We propose solutions to these problems and posit that assessing these parameters is crucial for considering the potential of metabolic modifiers in sensitizing tumors to immunotherapies.

The Cancer Antioxidant Regulation System in Therapeutic Resistance

Antioxidants play a pivotal role in neutralizing reactive oxygen species (ROS), which are known to induce oxidative stress. In the context of cancer development, cancer cells adeptly maintain elevated levels of both ROS and antioxidants through a process termed "redox reprogramming". This balance optimizes the proliferative influence of ROS while simultaneously reducing the potential for ROS to cause damage to the cell. In some cases, the adapted antioxidant machinery can hamper the efficacy of treatments for neoplastic diseases, representing a significant facet of the resistance mechanisms observed in cancer therapy. In this review, we outline the contribution of antioxidant systems to therapeutic resistance. We detail the fundamental constituents of these systems, encompassing the central regulatory mechanisms involving transcription factors (of particular importance is the KEAP1/NRF2 signaling axis), the molecular effectors of antioxidants, and the auxiliary systems responsible for NADPH generation. Furthermore, we present recent clinical trials based on targeted antioxidant systems for the treatment of cancer, assessing the potential as well as challenges of this strategy in cancer therapy. Additionally, we summarize the pressing issues in the field, with the aim of illuminating a path toward the emergence of novel anticancer therapeutic approaches by orchestrating redox signaling.

Comparison of outcomes for Hispanic and non-Hispanic patients with advanced renal cell carcinoma in the International Metastatic Renal Cell Carcinoma Database

BACKGROUND

Existing data on the impact of Hispanic ethnicity on outcomes for patients with renal cell carcinoma (RCC) is mixed. The authors investigated outcomes of Hispanic and non-Hispanic White (NHW) patients with advanced RCC receiving systemic therapy at large academic cancer centers using the International Metastatic Renal Cell Carcinoma Database (IMDC).

METHODS

Eligible patients included non-Black Hispanic and NHW patients with locally advanced or metastatic RCC initiating systemic therapy. Overall survival (OS) and time to first-line treatment failure (TTF) were calculated using the Kaplan-Meier method. The effect of ethnicity on OS and TTF were estimated by Cox regression hazard ratios (HRs).

RESULTS

A total of 1563 patients (181 Hispanic and 1382 NHW) (mostly males [73.8%] with clear cell RCC [81.5%] treated with tyrosine kinase inhibitor [TKI] monotherapy [69.9%]) were included. IMDC risk groups were similar between groups. Hispanic patients were younger at initial diagnosis (median 57 vs. 59 years, p = .015) and less likely to have greater than one metastatic site (60.8% vs. 76.8%, p < .001) or bone metastases (23.8% vs. 33.4%, p = .009). Median OS and TTF was 38.0 months (95% confidence interval [CI], 28.1-59.2) versus 35.7 months (95% CI, 31.9-39.2) and 7.8 months (95% CI, 6.2-9.0) versus 7.5 months (95% CI, 6.9-8.1), respectively, in Hispanic versus NHW patients. In multivariable Cox regression analysis, no statistically significant differences were observed in OS (adjusted hazard ratio [HR], 1.07; 95% CI, 0.86-1.31, p = .56) or TTF (adjusted HR, 1.06; 95% CI, 0.89-1.26, p = .50).

CONCLUSIONS

The authors did not observe statistically significant differences in OS or TTF between Hispanic and NHW patients with advanced RCC. Receiving treatment at tertiary cancer centers may mitigate observed disparities in cancer outcomes.

Targeting the glutamine metabolism to suppress cell proliferation in mesenchymal docetaxel-resistant prostate cancer

Docetaxel (DX) serves as a palliative treatment option for metastatic prostate cancer (PCa). Despite initial remission, acquired DX resistance is inevitable. The mechanisms behind DX resistance have not yet been deciphered, but a mesenchymal phenotype is associated with DX resistance. Mesenchymal phenotypes have been linked to metabolic rewiring, obtaining most ATP production by oxidative phosphorylation (OXPHOS) powered substantially by glutamine (Gln). Likewise, Gln is known to play an essential role in modulating bioenergetic, redox homeostasis and autophagy. Herein, investigations of Gln deprivation on DX-sensitive and -resistant (DR) PCa cells revealed that the DR cell sub-lines were susceptible to Gln deprivation. Mechanistically, Gln deprivation reduced OXPHOS and ATP levels, causing a disturbance in cell cycle progression. Genetic and chemical inhibition of the Gln-metabolism key protein GLS1 could validate the Gln deprivation results, thereby representing a valid therapeutic target. Moreover, immunohistological investigation of GLS1 revealed a high-expressing GLS1 subgroup post-docetaxel failure, exhibiting low overall survival. This subgroup presents an intriguing opportunity for targeted therapy focusing on glutamine metabolism. Thus, these findings highlight a possible clinical rationale for the chemical inhibition of GLS1 as a therapeutic strategy to target mesenchymal DR PCa cells, thereby delaying accelerated tumour progression.

Emerging Novel Functional Imaging and Immunotherapy in Renal Cell Carcinoma and Current Treatment Sequencing Strategies After Immunotherapy

The management of renal cell carcinoma (RCC) has advanced significantly in the past two decades. Many promising functional imaging modalities such as radiolabeled tracer targeting carbonic anhydrase IX and prostate-specific membrane antigen are under development to detect primary kidney tumors, stage systemic disease, and assess treatment response in RCC. Immune checkpoint inhibitors targeting PD-1 and cytotoxic T-cell lymphocyte-4 have changed the treatment paradigm in advanced RCC. Trials investigating novel mechanisms such as LAG-3 immune checkpoint inhibition, chimeric antigen receptor T-cell therapies, and T-cell engagers targeting RCC-associated antigens are currently ongoing. With the rapidly changing treatment landscape of RCC, the treatment sequence strategies will continue to evolve. Familiarity with the toxicities associated with the therapeutic agents and how to manage them are essential to achieve optimal patient outcomes. This review summarizes the recent developments of functional imaging and immunotherapy strategies in RCC, and the evidence supports treatment sequencing.

Stable Isotope Tracing Analysis in Cancer Research: Advancements and Challenges in Identifying Dysregulated Cancer Metabolism and Treatment Strategies

Metabolic reprogramming is a hallmark of cancer, driving the development of therapies targeting cancer metabolism. Stable isotope tracing has emerged as a widely adopted tool for monitoring cancer metabolism both in vitro and in vivo. Advances in instrumentation and the development of new tracers, metabolite databases, and data analysis tools have expanded the scope of cancer metabolism studies across these scales. In this review, we explore the latest advancements in metabolic analysis, spanning from experimental design in stable isotope-labeling metabolomics to sophisticated data analysis techniques. We highlight successful applications in cancer research, particularly focusing on ongoing clinical trials utilizing stable isotope tracing to characterize disease progression, treatment responses, and potential mechanisms of resistance to anticancer therapies. Furthermore, we outline key challenges and discuss potential strategies to address them, aiming to enhance our understanding of the biochemical basis of cancer metabolism.

Therapeutic resurgence of 6-diazo-5-oxo-l-norleucine (DON) through tissue-targeted prodrugs

The recognition that rapidly proliferating cancer cells rely heavily on glutamine for their survival and growth has renewed interest in the development of glutamine antagonists for cancer therapy. Glutamine plays a pivotal role as a carbon source for synthesizing lipids and metabolites through the TCA cycle, as well as a nitrogen source for synthesis of amino acid and nucleotides. Numerous studies have explored the significance of glutamine metabolism in cancer, providing a robust rationale for targeting this metabolic pathway in cancer treatment. The glutamine antagonist 6-diazo-5-oxo-l-norleucine (DON) has been explored as an anticancer therapeutic for nearly six decades. Initial investigations revealed remarkable efficacy in preclinical studies and promising outcomes in early clinical trials. However, further advancement of DON was hindered due to dose-limiting gastrointestinal (GI) toxicities as the GI system is highly dependent on glutamine for regulating growth and repair. In an effort to repurpose DON and mitigate gastrointestinal (GI) toxicity concerns, prodrug strategies were utilized. These strategies aimed to enhance the delivery of DON to specific target tissues, such as tumors and the central nervous system (CNS), while sparing DON delivery to normal tissues, particularly the GI tract. When administered at low daily doses, optimized for metabolic inhibition, these prodrugs exhibit remarkable effectiveness without inducing significant toxicity to normal tissues. This approach holds promise for overcoming past challenges associated with DON, offering an avenue for its successful utilization in cancer treatment.

HIF2α-dependent inhibition of mitochondrial clustering of glutaminase suppresses clear cell renal cell carcinoma

Clear cell renal cell carcinomas (ccRCC) are largely driven by HIF2α and are avid consumers of glutamine. However, inhibitors of glutaminase1 (GLS1), the first step in glutaminolysis, have not shown benefit in phase III trials, and HIF2α inhibition, recently FDA-approved for treatment of ccRCC, shows great but incomplete benefits, underscoring the need to better understand the roles of glutamine and HIF2α in ccRCC. Here, we report that glutamine deprivation rapidly redistributes GLS1 into isolated clusters within mitochondria across diverse cell types, excluding ccRCC. GLS1 clustering is rapid (1-3 hours) and reversible, is specifically driven by the level of intracellular glutamate, and is mediated by mitochondrial fission. Clustered GLS1 has markedly enhanced glutaminase activity and promotes cell death under glutamine-deprived conditions. We further show that HIF2α prevents GLS1 clustering, independently of its transcriptional activity, thereby protecting ccRCC cells from cell death induced by glutamine deprivation. Reversing this protection, by genetic expression of GLS1 mutants that constitutively cluster, enhances ccRCC cell death in culture and suppresses ccRCC growth in vivo . These finding provide multiple insights into cellular glutamine handling, including a novel metabolic pathway by which HIF2α promotes ccRCC, and reveals a potential therapeutic avenue to synergize with HIF2α inhibition in the treatment of ccRCC.

Abnormal changes in metabolites caused by m6A methylation modification: The leading factors that induce the formation of immunosuppressive tumor microenvironment and their promising potential for clinical application

BACKGROUND

N6-methyladenosine (m6A) RNA methylation modifications have been widely implicated in the metabolic reprogramming of various cell types within the tumor microenvironment (TME) and are essential for meeting the demands of cellular growth and maintaining tissue homeostasis, enabling cells to adapt to the specific conditions of the TME. An increasing number of research studies have focused on the role of m6A modifications in glucose, amino acid and lipid metabolism, revealing their capacity to induce aberrant changes in metabolite levels. These changes may in turn trigger oncogenic signaling pathways, leading to substantial alterations within the TME. Notably, certain metabolites, including lactate, succinate, fumarate, 2-hydroxyglutarate (2-HG), glutamate, glutamine, methionine, S-adenosylmethionine, fatty acids and cholesterol, exhibit pronounced deviations from normal levels. These deviations not only foster tumorigenesis, proliferation and angiogenesis but also give rise to an immunosuppressive TME, thereby facilitating immune evasion by the tumor.

AIM OF REVIEW

The primary objective of this review is to comprehensively discuss the regulatory role of m6A modifications in the aforementioned metabolites and their potential impact on the development of an immunosuppressive TME through metabolic alterations.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review aims to elaborate on the intricate networks governed by the m6A-metabolite-TME axis and underscores its pivotal role in tumor progression. Furthermore, we delve into the potential implications of the m6A-metabolite-TME axis for the development of novel and targeted therapeutic strategies in cancer research.

Metabolic alterations in hereditary and sporadic renal cell carcinoma

Kidney cancer is the seventh leading cause of cancer in the world, and its incidence is on the rise. Renal cell carcinoma (RCC) is the most common form and is a heterogeneous disease comprising three major subtypes that vary in their histology, clinical course and driver mutations. These subtypes include clear cell RCC, papillary RCC and chromophobe RCC. Molecular analyses of hereditary and sporadic forms of RCC have revealed that this complex and deadly disease is characterized by metabolic pathway alterations in cancer cells that lead to deregulated oxygen and nutrient sensing, as well as impaired tricarboxylic acid cycle activity. These metabolic changes facilitate tumour growth and survival. Specifically, studies of the metabolic features of RCC have led to the discovery of oncometabolites - fumarate and succinate - that can promote tumorigenesis, moonlighting functions of enzymes, and substrate auxotrophy owing to the disruption of pathways that enable the production of arginine and cholesterol. These metabolic alterations within RCC can be exploited to identify new therapeutic targets and interventions, in combination with novel approaches that minimize the systemic toxicity of metabolic inhibitors and reduce the risk of drug resistance owing to metabolic plasticity.

RNA modifications in cellular metabolism: implications for metabolism-targeted therapy and immunotherapy

Cellular metabolism is an intricate network satisfying bioenergetic and biosynthesis requirements of cells. Relevant studies have been constantly making inroads in our understanding of pathophysiology, and inspiring development of therapeutics. As a crucial component of epigenetics at post-transcription level, RNA modification significantly determines RNA fates, further affecting various biological processes and cellular phenotypes. To be noted, immunometabolism defines the metabolic alterations occur on immune cells in different stages and immunological contexts. In this review, we characterize the distribution features, modifying mechanisms and biological functions of 8 RNA modifications, including N6-methyladenosine (m6A), N6,2'-O-dimethyladenosine (m6Am), N1-methyladenosine (m1A), 5-methylcytosine (m5C), N4-acetylcytosine (ac4C), N7-methylguanosine (m7G), Pseudouridine (Ψ), adenosine-to-inosine (A-to-I) editing, which are relatively the most studied types. Then regulatory roles of these RNA modification on metabolism in diverse health and disease contexts are comprehensively described, categorized as glucose, lipid, amino acid, and mitochondrial metabolism. And we highlight the regulation of RNA modifications on immunometabolism, further influencing immune responses. Above all, we provide a thorough discussion about clinical implications of RNA modification in metabolism-targeted therapy and immunotherapy, progression of RNA modification-targeted agents, and its potential in RNA-targeted therapeutics. Eventually, we give legitimate perspectives for future researches in this field from methodological requirements, mechanistic insights, to therapeutic applications.

Cancer Metabolism under Limiting Oxygen Conditions

Molecular oxygen (O2) is essential for cellular bioenergetics and numerous biochemical reactions necessary for life. Solid tumors outgrow the native blood supply and diffusion limits of O2, and therefore must engage hypoxia response pathways that evolved to withstand acute periods of low O2 Hypoxia activates coordinated gene expression programs, primarily through hypoxia inducible factors (HIFs), to support survival. Many of these changes involve metabolic rewiring such as increasing glycolysis to support ATP generation while suppressing mitochondrial metabolism. Since low O2 is often coupled with nutrient stress in the tumor microenvironment, other responses to hypoxia include activation of nutrient uptake pathways, metabolite scavenging, and regulation of stress and growth signaling cascades. Continued development of models that better recapitulate tumors and their microenvironments will lead to greater understanding of oxygen-dependent metabolic reprogramming and lead to more effective cancer therapies.

Vascular endothelial growth factor-targeted therapy in patients with renal cell carcinoma pretreated with immune checkpoint inhibitors: A systematic literature review

INTRODUCTION

We conducted a systematic literature review to identify evidence for use of vascular endothelial growth factor (VEGF)-targeted (anti-VEGF) treatment in patients with renal cell carcinoma (RCC) following prior checkpoint inhibitor (CPI)-based therapy.

METHODS

This was a PRISMA-standard systematic literature review; registered with PROSPERO (CRD42021255568). Literature searches were conducted in MEDLINE®, Embase, and the Cochrane Library (January 28, 2021; updated September 13, 2022) to identify publications reporting efficacy/effectiveness and safety/tolerability evidence for anti-VEGF treatment in patients with RCC who had received prior CPI therapy.

RESULTS

Of 2,639 publications screened, 48 were eligible and featured 2,759 patients treated in trials and 2,209 in real-world studies (RWS). Most patients with available data were treated with anti-VEGF tyrosine kinase inhibitor-based regimens (trials: 93 %; RWS: 100 %), most commonly cabozantinib, which accounted for 46 % of trial and 62 % of RWS patients in publications with available data. Collectively, there was consistent evidence of anti-VEGF treatment activity after prior CPI therapy. Activity was reported for all anti-VEGF regimens and regardless of prior CPI-based regimen. No new safety signals were detected for subsequent anti-VEGF therapy; no studies suggested increased immune-related adverse events associated with prior CPI therapy. The results were limited by data quality; study heterogeneity prohibited meta-analyses.

CONCLUSION

Based on the available data (most commonly for cabozantinib), anti-VEGF therapy appears to be a rational treatment choice in patients with RCC who have progressed despite prior CPI-based therapy. Results from ongoing trials of combination anti-VEGF plus CPI regimen post prior CPI therapy trials will contribute more definitive evidence.

PLAIN LANGUAGE SUMMARY

Anticancer treatments that work by reducing levels of a substance in the body called Vascular Endothelial Growth Factor are known as anti-VEGF drugs. Reducing VEGF levels helps to reduce blood supply to tumors, which can slow the speed at which the cancer grows. Some other types of anticancer drugs that help the immune system to fight cancer cells are called checkpoint inhibitors. Here, we looked at published studies that investigated how anti-VEGF drugs work, and what side effects they cause, in people who have already been treated with checkpoint inhibitors for a type of kidney cancer called renal cell carcinoma. We aimed to summarize the available evidence to help doctors decide how best to use anti-VEGF drugs in these patients. We found 48 studies that included almost 5,000 patients. The results of the studies showed that anti-VEGF drugs have anticancer effects in people with renal cell carcinoma who had already been treated with checkpoint inhibitors. All of the VEGF-targeting drugs had anticancer effects, irrespective of what checkpoint inhibitor treatment people had received before. There were different amounts of evidence available for the different anti-VEGF drugs. The anti-VEGF cabozantinib had the largest amount of evidence. Importantly, previous checkpoint inhibitor treatment did not seem to affect the number or type of side-effects associated with anti-VEGF drugs. Results from ongoing, well-designed studies will be helpful to confirm these results. Our findings may be useful for doctors considering using anti-VEGF drugs in patients with renal cell carcinoma who have received checkpoint inhibitor treatment.

Activity of cabozantinib in further line treatment of metastatic clear cell renal cell carcinoma. Real-world experience in a single-center retrospective study

Introduction

Cabozantinib is an oral inhibitor of MET, AXL, and vascular endothelial growth factor receptors. It has an immunomodulatory effect and may influence the tumor's microenvironment and make mutated cells more sensitive to immune-mediated killing. These properties have made cabozantinib an effective drug for first-line or subsequent-line treatment after progression of metastatic renal cell carcinoma (mRCC), even after immunotherapy.

Material and methods

Seventy-one patients with mRCC were treated with second or further lines of cabozantinib at the Department of Genitourinary Oncology, Maria Sklodowska-Curie National Research Institute of Oncology. This study retrospectively evaluated the effectiveness of cabozantinib in subsequent lines of treatment. Progression-free survival (PFS) and overall survival (OS) were the primary endpoints. The best overall response (BOR) to cabozantinib was the secondary endpoint. For this purpose, Cox's proportional hazard model was used.

Results

The median PFS was 11 months (5; 23) and the median OS was 16 months (10; 42) and differed significantly in the second and further lines of treatment. Progression in the second and further lines was observed in 28 (93%) and 27 (66%) patients, respectively (p = 0.006). Partial response as the BOR was observed in one patient (3%) in the second line and 13 patients (32%) in the further lines (p = 0.012).

Conclusions

Cabozantinib has antitumor effects in the second and further lines of treatment. In this study we observed high efficiency of cabozantinib in further lines of treatment.

Metabolic pathway analysis using stable isotopes in patients with cancer

Metabolic reprogramming is central to malignant transformation and cancer cell growth. How tumours use nutrients and the relative rates of reprogrammed pathways are areas of intense investigation. Tumour metabolism is determined by a complex and incompletely defined combination of factors intrinsic and extrinsic to cancer cells. This complexity increases the value of assessing cancer metabolism in disease-relevant microenvironments, including in patients with cancer. Stable-isotope tracing is an informative, versatile method for probing tumour metabolism in vivo. It has been used extensively in preclinical models of cancer and, with increasing frequency, in patients with cancer. In this Review, we describe approaches for using in vivo isotope tracing to define fuel preferences and pathway engagement in tumours, along with some of the principles that have emerged from this work. Stable-isotope infusions reported so far have revealed that in humans, tumours use a diverse set of nutrients to supply central metabolic pathways, including the tricarboxylic acid cycle and amino acid synthesis. Emerging data suggest that some activities detected by stable-isotope tracing correlate with poor clinical outcomes and may drive cancer progression. We also discuss current challenges in isotope tracing, including comparisons of in vivo and in vitro models, and opportunities for future discovery in tumour metabolism.

Treatment Landscape of Renal Cell Carcinoma

OPINION STATEMENT

The treatment landscape of renal cell carcinoma (RCC) has evolved significantly over the past three decades. Active surveillance and tumor ablation are alternatives to extirpative therapy in appropriately selected patients. Stereotactic body radiation therapy (SBRT) is an emerging noninvasive alternative to treat primary RCC tumors. The advent of immune checkpoint inhibitors (ICIs) has greatly improved the overall survival of advanced RCC, and now the ICI-based doublet (dual ICI-ICI doublet; or ICI in combination with a vascular endothelial growth factor tyrosine kinase inhibitor, ICI-TKI doublet) has become the standard frontline therapy. Based on unprecedented outcomes in the metastatic with ICIs, they are also being explored in the neoadjuvant and adjuvant setting for patients with high-risk disease. Adjuvant pembrolizumab has proven efficacy to reduce the risk of RCC recurrence after nephrectomy. Historically considered a radioresistant tumor, SBRT occupies an expanding role to treat RCC with oligometastasis or oligoprogression in combination with systemic therapy. Furthermore, SBRT is being investigated in combination with ICI-doublet in the advanced disease setting. Lastly, given the treatment paradigm is shifting to adopt ICIs at earlier disease course, the prospective studies guiding treatment sequencing in the post-ICI setting is maturing. The effort is ongoing in search of predictive biomarkers to guide optimal treatment option in RCC.

The immunometabolic ecosystem in cancer

Our increased understanding of how key metabolic pathways are activated and regulated in malignant cells has identified metabolic vulnerabilities of cancers. Translating this insight to the clinics, however, has proved challenging. Roadblocks limiting efficacy of drugs targeting cancer metabolism may lie in the nature of the metabolic ecosystem of tumors. The exchange of metabolites and growth factors between cancer cells and nonmalignant tumor-resident cells is essential for tumor growth and evolution, as well as the development of an immunosuppressive microenvironment. In this Review, we will examine the metabolic interplay between tumor-resident cells and how targeted inhibition of specific metabolic enzymes in malignant cells could elicit pro-tumorigenic effects in non-transformed tumor-resident cells and inhibit the function of tumor-specific T cells. To improve the efficacy of metabolism-targeted anticancer strategies, a holistic approach that considers the effect of metabolic inhibitors on major tumor-resident cell populations is needed.

Metabolic reprogramming: Unveiling the therapeutic potential of targeted therapies against kidney disease

As a high-metabolic-rate organ, the kidney exhibits metabolic reprogramming (MR) in various disease states. Given the >800 million cases of kidney disease worldwide in 2022, understanding the specific bioenergetic pathways involved and developing targeted interventions are vital needs. The reprogramming of metabolic pathways (glucose metabolism, amino acid metabolism, etc.) has been observed in kidney disease. Therapies targeting these specific pathways have proven to be an efficient approach for retarding kidney disease progression. In this review, we focus on potential pharmacological interventions targeting MR that have advanced through Phase III/IV clinical trials for the management of kidney disease and promising preclinical studies laying the groundwork for future clinical investigations.

Canagliflozin reduces chemoresistance in hepatocellular carcinoma through PKM2-c-Myc complex-mediated glutamine starvation

Cisplatin (CPT) is one of the standard treatments for hepatocellular carcinoma (HCC). However, its use is limits as a monotherapy due to drug resistance, and the underlying mechanism remains unclear. To solve this problem, we tried using canagliflozin (CANA), a clinical drug for diabetes, to reduce chemoresistance to CPT, and the result showed that CANA could vigorously inhibit cell proliferation and migration independent of the original target SGLT2. Mechanistically, CANA reduced aerobic glycolysis in HCC by targeting PKM2. The downregulated PKM2 directly bound to the transcription factor c-Myc in the cytoplasm to form a complex, which upregulated the level of phosphorylated c-Myc Thr58 and promoted the ubiquitination and degradation of c-Myc. Decreased c-Myc reduced the expression of GLS1, a key enzyme in glutamine metabolism, leading to impaired glutamine utilization. Finally, intracellular glutamine starvation induced ferroptosis and sensitized HCC to CPT. In conclusion, our study showed that CANA re-sensitized HCC to CPT by inducing ferroptosis through dual effects on glycolysis and glutamine metabolism. This is a novel mechanism to increase chemosensitivity, which may provide compatible chemotherapy drugs for HCC.

Managing Metastatic Renal Cell Carcinoma after Progression on Immunotherapy

Treatment of metastatic renal cell carcinoma (mRCC) after first-line immune checkpoint inhibitors (ICIs) lacks standardization, with limited evidence from small trials and retrospective data. Vascular endothelial growth factor receptor (VEGFR) inhibition through tyrosine kinase inhibitors (TKIs) is the most widely adopted second-line treatment. Encouraging results have been seen with VEGFR-TKIs in the second-line after exposure to an ICI-based combination, achieving a response rate of 30%, and 75% of patients achieving disease control. Rechallenge with ICI alone seems safe but has limited clinical benefit. Promising regimens with combination therapies and novel drugs are being evaluated in phase 3 trials.

Immunobiology and Metabolic Pathways of Renal Cell Carcinoma

The treatment of advanced renal cell carcinoma (RCC) has changed dramatically with immune checkpoint inhibitors, yet most patients do not have durable responses. There is consequently a tremendous need for novel therapeutic development. RCC, and particularly the most common histology clear cell RCC, is an immunobiologically and metabolically distinct tumor. An improved understanding of RCC-specific biology will be necessary for the successful identification of new treatment targets for this disease. In this review, we discuss the current understanding of RCC immune pathways and metabolic dysregulation, with a focus on topics important for future clinical development.

Novel Targeted Therapies for Renal Cell Carcinoma: Building on the Successes of Vascular Endothelial Growth Factor and mTOR Inhibition

Targeted therapies have revolutionized the treatment of renal cell carcinoma (RCC). The VHL/HIF pathway is responsible for the regulation of oxygen homeostasis and is frequently altered in RCC. Targeting this pathway as well as the mTOR pathway have yielded remarkable advances in the treatment of RCC. Here, we review the most promising novel targeted therapies for the treatment of RCC, including HIF2α, MET, metabolic targeting, and epigenomic reprogramming.

An Overview of Systemic Targeted Therapy in Renal Cell Carcinoma, with a Focus on Metastatic Renal Cell Carcinoma and Brain Metastases

The most commonly diagnosed malignancy of the urinary system is represented by renal cell carcinoma. Various subvariants of RCC were described, with a clear-cell type prevailing in about 85% of all RCC tumors. Patients with metastases from renal cell carcinoma did not have many effective therapies until the end of the 1980s, as long as hormonal therapy and chemotherapy were the only options available. The outcomes were unsatisfactory due to the poor effectiveness of the available therapeutic options, but then interferon-alpha and interleukin-2 showed treatment effectiveness, providing benefits but only for less than half of the patients. However, it was not until 2004 that targeted therapies emerged, prolonging the survival rate. Currently, new technologies and strategies are being developed to improve the actual efficacy of available treatments and their prognostic aspects. This article summarizes the mechanisms of action, importance, benefits, adverse events of special interest, and efficacy of immunotherapy in metastatic renal cell carcinoma, with a focus on brain metastases.

Tumor microenvironmental nutrients, cellular responses, and cancer

Over the last two decades, the rapidly expanding field of tumor metabolism has enhanced our knowledge of the impact of nutrient availability on metabolic reprogramming in cancer. Apart from established roles in cancer cells themselves, various nutrients, metabolic enzymes, and stress responses are key to the activities of tumor microenvironmental immune, fibroblastic, endothelial, and other cell types that support malignant transformation. In this article, we review our current understanding of how nutrient availability affects metabolic pathways and responses in both cancer and "stromal" cells, by dissecting major examples and their regulation of cellular activity. Understanding the relationship of nutrient availability to cellular behaviors in the tumor ecosystem will broaden the horizon of exploiting novel therapeutic vulnerabilities in cancer.

Pyruvate Kinase Activity Regulates Cystine Starvation Induced Ferroptosis through Malic Enzyme 1 in Pancreatic Cancer Cells

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with high mortality and limited efficacious therapeutic options. PDAC cells undergo metabolic alterations to survive within a nutrient-depleted tumor microenvironment. One critical metabolic shift in PDAC cells occurs through altered isoform expression of the glycolytic enzyme, pyruvate kinase (PK). Pancreatic cancer cells preferentially upregulate pyruvate kinase muscle isoform 2 isoform (PKM2). PKM2 expression reprograms many metabolic pathways, but little is known about its impact on cystine metabolism. Cystine metabolism is critical for supporting survival through its role in defense against ferroptosis, a non-apoptotic iron-dependent form of cell death characterized by unchecked lipid peroxidation. To improve our understanding of the role of PKM2 in cystine metabolism and ferroptosis in PDAC, we generated PKM2 knockout (KO) human PDAC cells. Fascinatingly, PKM2KO cells demonstrate a remarkable resistance to cystine starvation mediated ferroptosis. This resistance to ferroptosis is caused by decreased PK activity, rather than an isoform-specific effect. We further utilized stable isotope tracing to evaluate the impact of glucose and glutamine reprogramming in PKM2KO cells. PKM2KO cells depend on glutamine metabolism to support antioxidant defenses against lipid peroxidation, primarily by increased glutamine flux through the malate aspartate shuttle and utilization of ME1 to produce NADPH. Ferroptosis can be synergistically induced by the combination of PKM2 activation and inhibition of the cystine/glutamate antiporter in vitro. Proof-of-concept in vivo experiments demonstrate the efficacy of this mechanism as a novel treatment strategy for PDAC.

Rewiring of mitochondrial metabolism in therapy-resistant cancers: permanent and plastic adaptations

Deregulation of tumor cell metabolism is widely recognized as a "hallmark of cancer." Many of the selective pressures encountered by tumor cells, such as exposure to anticancer therapies, navigation of the metastatic cascade, and communication with the tumor microenvironment, can elicit further rewiring of tumor cell metabolism. Furthermore, phenotypic plasticity has been recently appreciated as an emerging "hallmark of cancer." Mitochondria are dynamic organelles and central hubs of metabolism whose roles in cancers have been a major focus of numerous studies. Importantly, therapeutic approaches targeting mitochondria are being developed. Interestingly, both plastic (i.e., reversible) and permanent (i.e., stable) metabolic adaptations have been observed following exposure to anticancer therapeutics. Understanding the plastic or permanent nature of these mechanisms is of crucial importance for devising the initiation, duration, and sequential nature of metabolism-targeting therapies. In this review, we compare permanent and plastic mitochondrial mechanisms driving therapy resistance. We also discuss experimental models of therapy-induced metabolic adaptation, therapeutic implications for targeting permanent and plastic metabolic states, and clinical implications of metabolic adaptations. While the plasticity of metabolic adaptations can make effective therapeutic treatment challenging, understanding the mechanisms behind these plastic phenotypes may lead to promising clinical interventions that will ultimately lead to better overall care for cancer patients.

Cancer Metabolism Historical Perspectives: A Chronicle of Controversies and Consensus

A century ago, Otto Warburg's work sparked the field of cancer metabolism, which has since taken a tortuous path. As evidence accumulated over the decades, consensus views of causes of cancer emerged, whereby genetic and epigenetic oncogenic drivers promoted immune evasion and induced new blood vessels and neoplastic metabolism to support tumor growth. Neoplastic cells abandon social cues of intercellular cooperation, escape tissue confinement, metastasize, and ultimately kill the host. Herein, key milestones in the study of cancer metabolism are chronicled with an emphasis on carbohydrate metabolism. The field began with a cancer cell-autonomous view that has been refined by a richer understanding of solid cancers as growing, immune-suppressive, complex organs comprising different cell types that are nourished by a variety of nutrients and variable amounts of oxygen through abnormal neovasculatures. Based on foundational historical studies, our current understanding of cancer metabolism offers a hopeful outlook for targeting metabolism to enhance cancer therapy.

Emerging therapies in cancer metabolism

Metabolic reprogramming in cancer is not only a biological hallmark but also reveals treatment vulnerabilities. Numerous metabolic molecules have shown promise as treatment targets to impede tumor progression in preclinical studies, with some advancing to clinical trials. However, the intricacy and adaptability of metabolic networks hinder the effectiveness of metabolic therapies. This review summarizes the metabolic targets for cancer treatment and provides an overview of the current status of clinical trials targeting cancer metabolism. Additionally, we decipher crucial factors that limit the efficacy of metabolism-based therapies and propose future directions. With advances in integrating multi-omics, single-cell, and spatial technologies, as well as the ability to track metabolic adaptation more precisely and dynamically, clinicians can personalize metabolic therapies for improved cancer treatment.

Atezolizumab plus cabozantinib versus cabozantinib monotherapy for patients with renal cell carcinoma after progression with previous immune checkpoint inhibitor treatment (CONTACT-03): a multicentre, randomised, open-label, phase 3 trial

BACKGROUND

Immune checkpoint inhibitors are the standard of care for first-line treatment of patients with metastatic renal cell carcinoma, yet optimised treatment of patients whose disease progresses after these therapies is unknown. The aim of this study was to determine whether adding atezolizumab to cabozantinib delayed disease progression and prolonged survival in patients with disease progression on or after previous immune checkpoint inhibitor treatment.

METHODS

CONTACT-03 was a multicentre, randomised, open-label, phase 3 trial, done in 135 study sites in 15 countries in Asia, Europe, North America, and South America. Patients aged 18 years or older with locally advanced or metastatic renal cell carcinoma whose disease had progressed with immune checkpoint inhibitors were randomly assigned (1:1) to receive atezolizumab (1200 mg intravenously every 3 weeks) plus cabozantinib (60 mg orally once daily) or cabozantinib alone. Randomisation was done through an interactive voice-response or web-response system in permuted blocks (block size four) and stratified by International Metastatic Renal Cell Carcinoma Database Consortium risk group, line of previous immune checkpoint inhibitor therapy, and renal cell carcinoma histology. The two primary endpoints were progression-free survival per blinded independent central review and overall survival. The primary endpoints were assessed in the intention-to-treat population and safety was assessed in all patients who received at least one dose of study drug. The trial is registered with ClinicalTrials.gov, NCT04338269, and is closed to further accrual.

FINDINGS

From July 28, 2020, to Dec 27, 2021, 692 patients were screened for eligibility, 522 of whom were assigned to receive atezolizumab-cabozantinib (263 patients) or cabozantinib (259 patients). 401 (77%) patients were male and 121 (23%) patients were female. At data cutoff (Jan 3, 2023), median follow-up was 15·2 months (IQR 10·7-19·3). 171 (65%) patients receiving atezolizumab-cabozantinib and 166 (64%) patients receiving cabozantinib had disease progression per central review or died. Median progression-free survival was 10·6 months (95% CI 9·8-12·3) with atezolizumab-cabozantinib and 10·8 months (10·0-12·5) with cabozantinib (hazard ratio [HR] for disease progression or death 1·03 [95% CI 0·83-1·28]; p=0·78). 89 (34%) patients in the atezolizumab-cabozantinib group and 87 (34%) in the cabozantinib group died. Median overall survival was 25·7 months (95% CI 21·5-not evaluable) with atezolizumab-cabozantinib and was not evaluable (21·1-not evaluable) with cabozantinib (HR for death 0·94 [95% CI 0·70-1·27]; p=0·69). Serious adverse events occurred in 126 (48%) of 262 patients treated with atezolizumab-cabozantinib and 84 (33%) of 256 patients treated with cabozantinib; adverse events leading to death occurred in 17 (6%) patients in the atezolizumab-cabozantinib group and nine (4%) in the cabozantinib group.

INTERPRETATION

The addition of atezolizumab to cabozantinib did not improve clinical outcomes and led to increased toxicity. These results should discourage sequential use of immune checkpoint inhibitors in patients with renal cell carcinoma outside of clinical trials.

FUNDING

F Hoffmann-La Roche and Exelixis.

A core NRF2 gene set defined through comprehensive transcriptomic analysis predicts selective drug resistance and poor multi-cancer prognosis

The NRF2-KEAP1 pathway plays an important role in the cellular response to oxidative stress but may also contribute to metabolic changes and drug resistance in cancer. We investigated the activation of NRF2 in human cancers and fibroblast cells through KEAP1 inhibition and cancer associated KEAP1/NRF2 mutations. We define a core set of 14 upregulated NRF2 target genes from seven RNA-Sequencing databases that we generated and analyzed, which we validated this gene set through analyses of published databases and gene sets. An NRF2 activity score based on expression of these core target genes correlates with resistance to drugs such as PX-12 and necrosulfonamide but not to paclitaxel or bardoxolone methyl. We validated these findings and also found NRF2 activation led to radioresistance in cancer cell lines. Finally, our NRF2 score is prognostic for cancer survival and validated in additional independent cohorts for novel cancers types not associated with NRF2-KEAP1 mutations. These analyses define a core NRF2 gene set that is robust, versatile, and useful as a NRF2 biomarker and for predicting drug resistance and cancer prognosis.

Dietary Manipulation of Amino Acids for Cancer Therapy

Cancer cells cannot proliferate and survive unless they obtain sufficient levels of the 20 proteinogenic amino acids (AAs). Unlike normal cells, cancer cells have genetic and metabolic alterations that may limit their capacity to obtain adequate levels of the 20 AAs in challenging metabolic environments. However, since normal diets provide all AAs at relatively constant levels and ratios, these potentially lethal genetic and metabolic defects are eventually harmless to cancer cells. If we temporarily replace the normal diet of cancer patients with artificial diets in which the levels of specific AAs are manipulated, cancer cells may be unable to proliferate and survive. This article reviews in vivo studies that have evaluated the antitumor activity of diets restricted in or supplemented with the 20 proteinogenic AAs, individually and in combination. It also reviews our recent studies that show that manipulating the levels of several AAs simultaneously can lead to marked survival improvements in mice with metastatic cancers.

A second case of glutaminase hyperactivity: Expanding the phenotype with epilepsy

Glutaminase (GLS) hyperactivity was first described in 2019 in a patient with profound developmental delay and infantile cataract. Here, we describe a 4-year-old boy with GLS hyperactivity due to a de novo heterozygous missense variant in GLS, detected by trio whole exome sequencing. This boy also exhibits developmental delay without dysmorphic features, but does not have cataract. Additionally, he suffers from epilepsy with tonic clonic seizures. In line with the findings in the previously described patient with GLS hyperactivity, in vivo 3 T magnetic resonance spectroscopy (MRS) of the brain revealed an increased glutamate/glutamine ratio. This increased ratio was also found in urine with UPLC-MS/MS, however, inconsistently. This case indicates that the phenotypic spectrum evoked by GLS hyperactivity may include epilepsy. Clarifying this phenotypic spectrum is of importance for the prognosis and identification of these patients. The combination of phenotyping, genetic testing, and metabolic diagnostics with brain MRS and in urine is essential to identify new patients with GLS hyperactivity and to further extend the phenotypic spectrum of this disease.

Targeting Cancer Metabolism to Improve Outcomes with Immune Checkpoint Inhibitors

Immune checkpoint inhibitors have revolutionized the treatment paradigm of several cancers. However, not all patients respond to treatment. Tumor cells reprogram metabolic pathways to facilitate growth and proliferation. This shift in metabolic pathways creates fierce competition with immune cells for nutrients in the tumor microenvironment and generates by-products harmful for immune cell differentiation and growth. In this review, we discuss these metabolic alterations and the current therapeutic strategies to mitigate these alterations to metabolic pathways that can be used in combination with checkpoint blockade to offer a new path forward in cancer management.

Two is company, is three a crowd? Triplet therapy, novel molecular targets, and updates on the management of advanced renal cell carcinoma

PURPOSE OF REVIEW

The purpose of this review is to highlight the most recent changes in the management of advanced renal cell carcinoma, a complicated and ever-changing field of research.

RECENT FINDINGS

A recent meta-analysis examining combination therapy favors nivolumab plus cabozantinib as the overall survival leader in doublet therapy. Initial results on the first ever trial of triplet therapy have demonstrated improved progression-free survival over current standard of care. The hypoxia-inducible factor-2α (HIF-2α) inhibitor belzutifan is FDA approved for patients with von Hippel-Lindau disease and is currently being investigated in patients with nonhereditary renal cell carcinoma. The new glutamate synthesis inhibitor, telaglenastat, perhaps confers synergistic benefit when combined with everolimus, but combination with cabozantinib was not so effective. Dual mammalian target of rapamycin (mTOR) inhibition with sapanisertib does not appear to be an effective therapeutic option. New biomarkers and targets are actively being investigated. Four recent trials examining alternative agents to pembrolizumab in the adjuvant setting did not demonstrate an improvement in recurrence-free survival. Cytoreductive nephrectomy in the combination therapy era is supported by retrospective data; clinical trials are recruiting patients.

SUMMARY

The last year ushered in novel approaches of varying success for managing advanced renal cell carcinoma, including triplet therapy, HIF-2α inhibitors, metabolic pathway inhibitors, and dual mTOR inhibitors. Pembrolizumab remains the only modern therapy available in the adjuvant setting, and the waters surrounding cytoreductive nephrectomy are still murky.

The Therapeutic Landscape for KRAS-Mutated Colorectal Cancers

Colorectal cancer is one of the world's most prevalent and lethal cancers. Mutations of the KRAS gene occur in ~40% of metastatic colorectal cancers. While this cohort has historically been difficult to manage, the last few years have shown exponential growth in the development of selective inhibitors targeting KRAS mutations. Their foremost mechanism of action utilizes the Switch II binding pocket and Cys12 residue of GDP-bound KRAS proteins in G12C mutants, confining them to their inactive state. Sotorasib and Adagrasib, both FDA-approved for the treatment of non-small cell lung cancer (NSCLC), have been pivotal in paving the way for KRAS G12C inhibitors in the clinical setting. Other KRAS inhibitors in development include a multi-targeting KRAS-mutant drug and a G12D mutant drug. Treatment resistance remains an issue with combination treatment regimens including indirect pathway inhibition and immunotherapy providing possible ways to combat this. While KRAS-mutant selective therapy has come a long way, more work is required to make this an effective and viable option for patients with colorectal cancer.