The aggressive nature of pancreatic ductal adenocarcinoma (PDAC) mandates the development of improved therapies. As KRAS mutations are found in 95% of PDAC and are critical for tumor maintenance, one promising strategy involves exploiting KRAS-dependent metabolic perturbations. The macrometabolic process of autophagy is upregulated in KRAS-mutant PDAC, and PDAC growth is reliant on autophagy. However, inhibition of autophagy as monotherapy using the lysosomal inhibitor hydroxychloroquine (HCQ) has shown limited clinical efficacy. To identify strategies that can improve PDAC sensitivity to HCQ, we applied a CRISPR-Cas9 loss-of-function screen and found that a top sensitizer was the receptor tyrosine kinase (RTK) insulin-like growth factor 1 receptor (IGF1R). Additionally, reverse phase protein array pathway activation mapping profiled the signaling pathways altered by chloroquine (CQ) treatment. Activating phosphorylation of RTKs, including IGF1R, was a common compensatory increase in response to CQ. Inhibition of IGF1R increased autophagic flux and sensitivity to CQ-mediated growth suppression both in vitro and in vivo. Cotargeting both IGF1R and pathways that antagonize autophagy, such as ERK–MAPK axis, was strongly synergistic. IGF1R and ERK inhibition converged on suppression of glycolysis, leading to enhanced dependence on autophagy. Accordingly, concurrent inhibition of IGF1R, ERK, and autophagy induced cytotoxicity in PDAC cell lines and decreased viability in human PDAC organoids. In conclusion, targeting IGF1R together with ERK enhances the effectiveness of autophagy inhibitors in PDAC. Significance: Compensatory upregulation of IGF1R and ERK–MAPK signaling limits the efficacy of autophagy inhibitors chloroquine and hydroxychloroquine, and their concurrent inhibition synergistically increases autophagy dependence and chloroquine sensitivity in pancreatic ductal adenocarcinoma.

Intermittent fasting entails restricting food intake during specific times of day, days of the week, religious practice, or surrounding clinically important events. Herein, the metabolic and circadian rhythm mechanisms underlying the proposed benefits of intermittent fasting for the cancer population are described. We summarize epidemiological, preclinical, and clinical studies in cancer published between January 2020 and August 2022 and propose avenues for future research. An outstanding concern regarding the use of intermittent fasting among cancer patients is that fasting often results in caloric restriction, which can put patients already prone to malnutrition, cachexia, or sarcopenia at risk. Although clinical trials do not yet provide sufficient data to support the general use of intermittent fasting in clinical practice, this summary may be useful for patients, caregivers, and clinicians who are exploring intermittent fasting as part of their cancer journey for clinical outcomes and symptom management.

Immune checkpoint inhibitor (ICI) therapy has shown extraordinary promise at treating cancers otherwise resistant to treatment. However, for ICI therapy to be effective, it must overcome the metabolic limitations of the tumor microenvironment. Tumor metabolism has long been understood to be highly dysregulated, with potent immunosuppressive effects. Moreover, T cell activation and longevity within the tumor microenvironment are intimately tied to T cell metabolism and are required for the long-term efficacy of ICI therapy. We discuss in this review the intersection of metabolic competition in the tumor microenvironment, T cell activation and metabolism, the roles of tumor cell metabolism in immune evasion, and the impact of host metabolism in determining immune surveillance and ICI therapy outcomes. We also discussed the effects of obesity and calorie restriction—two important systemic metabolic perturbations that impact intrinsic metabolic pathways in T cells as well as cancer cells.

The reversibility of the procancer effects of obesity was interrogated in formerly obese C57BL/6 mice that lost weight via a nonrestricted low-fat diet (LFD) or 3 distinct calorie-restricted (CR) regimens (low-fat CR, Mediterranean-style CR, or intermittent CR). These mice, along with continuously obese mice and lean control mice, were orthotopically injected with E0771 cells, a mouse model of triple-negative breast cancer. Tumor weight, systemic cytokines, and incidence of lung metastases were elevated in the continuously obese and nonrestricted LFD mice relative to the 3 CR groups. Gene expression differed between the obese and all CR groups, but not the nonrestricted LFD group, for numerous tumoral genes associated with epithelial-to-mesenchymal transition as well as several genes in the normal mammary tissue associated with hypoxia, reactive oxygen species production, and p53 signaling. A high degree of concordance existed between differentially expressed mammary tissue genes from obese versus all CR mice and a microarray dataset from overweight/obese women randomized to either no intervention or a CR diet. Assessment of differentially methylated regions in mouse mammary tissues revealed that obesity, relative to the 4 weight loss groups, was associated with significant DNA hypermethylation. However, the anticancer effects of the CR interventions were independent of their ability to reverse obesity-associated mammary epigenetic reprogramming. Taken together, these preclinical data showing that the procancer effects of obesity are reversible by various forms of CR diets strongly support translational exploration of restricted dietary patterns for reducing the burden of obesity-associated cancers. Prevention Relevance: Obesity is an established risk and progression factor for triple-negative breast cancer (TNBC). Given rising global rates of obesity and TNBC, strategies to reduce the burden of obesity-driven TNBC are urgently needed. We report the genomic, epigenetic, and procancer effects of obesity are reversible by various calorie restriction regimens.

Obesity, an established risk and progression factor for at least 13 cancer types, is highly prevalent globally, and effective strategies to mitigate the burden of obesity-related cancer are urgently needed. We investigated whether tirzepatide, a widely used incretin-mimetic drug that induces substantial weight loss, offers anticancer benefits. Across 3 tumor models, we demonstrate that chronic tirzepatide treatment reverses diet-induced increases in body weight and fat mass, systemic metabolic perturbations, and tumor growth. We also showed that the anticancer activity of tirzepatide does not involve direct effects on the neoplastic cells used, which lack incretin receptor expression. The anticancer actions of tirzepatide require the reversal of both the metabolic dysregulation and hyporesponsiveness of CD8+ tumor infiltrating lymphocytes evident in obesity. Our findings establish tirzepatide as a promising compound for intercepting obesity-related cancers.

Background: Predictors of premature death and cancer development are needed to more precisely identify individuals who may warrant preventive intervention. Circulating insulin-like growth factor (IGF)–binding protein-7 (IGFBP7) and, to a lesser extent, the IGFBP7/IGF-1 ratio are emerging biomarkers of renal and cardiovascular morbidity. However, their relationships with aging, obesity, mortality, and cancer risk remain unclear. Methods: This hypothesis-generating study investigated plasma IGFBP7, IGF-1, and their ratio as predictors of all-cause mortality and the incidence of any cancer (excluding nonmelanoma skin cancer), obesity-related cancer (composite of 13 cancer types), and breast cancer in a large longitudinal cohort of postmenopausal women. We assessed the relationships of each biomarker with age, body mass index, and each outcome (bivariately and controlling for age, body mass index, race, physical activity, education, income, marital status, alcohol intake, smoking, diabetes, and hormone therapy) in 793 Women’s Health Initiative Observational Study participants (mean, 19.4-year follow-up). Results: In adjusted analyses, IGFBP7 increased with age and obesity and was positively associated with risks of all-cause mortality [HR = 2.42 (95% confidence interval, 1.37–4.26); P = 0.002], any cancer [HR = 2.04 (1.05–3.94); P = 0.035], and obesity-related cancer [HR = 1.58 (0.99–2.51); P = 0.053]. Also in adjusted analyses, the IGFBP7/IGF-1 ratio increased with age and was positively associated with all-cause mortality [HR = 1.51 (1.14–1.99); P = 0.004] and any cancer incidence [HR = 5.44 (1.13–26.1); P = 0.034]. Conclusions: Plasma IGFBP7 and the IGFBP7/IGF-1 ratio are positively associated with age, obesity (IGFBP7 only), mortality, and cancer in postmenopausal women. Impact: Plasma IGFBP7 may represent an age- and obesity-sensitive biomarker of increased risk of developing cancer and/or dying prematurely.