Squamous cell carcinoma (SCC), a malignancy arising across multiple anatomical sites, is responsible for significant cancer mortality due to insufficient therapeutic options. Here, we identify exceptional glucose reliance among SCCs dictated by hyperactive GLUT1-mediated glucose influx. Mechanistically, squamous lineage transcription factors p63 and SOX2 transactivate the intronic enhancer cluster of SLC2A1. Elevated glucose influx fuels generation of NADPH and GSH, thereby heightening the anti-oxidative capacity in SCC tumors. Systemic glucose restriction by ketogenic diet and inhibiting renal glucose reabsorption with SGLT2 inhibitor precipitate intratumoral oxidative stress and tumor growth inhibition. Furthermore, reduction of blood glucose lowers blood insulin levels, which suppresses PI3K/AKT signaling in SCC cells. Clinically, we demonstrate a robust correlation between blood glucose concentration and worse survival among SCC patients. Collectively, this study identifies the exceptional glucose reliance of SCC and suggests its candidacy as a highly vulnerable cancer type to be targeted by systemic glucose restriction.

Activation of the Hedgehog (Hh) signaling pathway by mutations within its components drives the growth of several cancers. However, the role of Hh pathway activation in lung cancers has been controversial. Here, we demonstrate that the canonical Hh signaling pathway is activated in lung stroma by Hh ligands secreted from transformed lung epithelia. Genetic deletion ofShh, the primary Hh ligand expressed in the lung, inKras^G12D/+;Trp53^fl/flautochthonous murine lung adenocarcinoma had no effect on survival. Early abrogation of the pathway by an anti-SHH/IHH antibody 5E1 led to significantly worse survival with increased tumor and metastatic burden. Loss of IHH, another Hh ligand, by in vivo CRISPR led to more aggressive tumor growth suggesting that IHH, rather than SHH, activates the pathway in stroma to drive its tumor suppressive effects—a novel role for IHH in the lung. Tumors from mice treated with 5E1 had decreased blood vessel density and increased DNA damage suggestive of reactive oxygen species (ROS) activity. Treatment ofKras^G12D/+;Trp53^fl/flmice with 5E1 and N-acetylcysteine, as a ROS scavenger, decreased tumor DNA damage, inhibited tumor growth and prolonged mouse survival. Thus, IHH induces stromal activation of the canonical Hh signaling pathway to suppress tumor growth and metastases, in part, by limiting ROS activity.

Squamous cell carcinomas (SCCs) arise from both stratified squamous and non-squamous epithelium of diverse anatomical sites and collectively represent one of the most frequent solid tumors, accounting for more than one million cancer deaths annually. Despite this prevalence, SCC patients have not fully benefited from recent advances in molecularly targeted therapy or immunotherapy. Rather, decades old platinum-based or radiation regimens retaining limited specificity to the unique characteristics of SCC remain first-line treatment options. Historically, a lack of a consolidated perspective on genetic aberrations driving oncogenic transformation and other such factors essential for SCC pathogenesis and intrinsic confounding cellular heterogeneity in SCC have contributed to a critical dearth in effective and specific therapies. However, emerging evidence characterizing the distinct genomic, epigenetic, and metabolic landscapes of SCC may be elucidating unifying features in a seemingly heterogeneous disease. In this review, by describing distinct metabolic alterations and genetic drivers of SCC revealed by recent studies, we aim to establish a conceptual framework for a previously unappreciated network of oncogenic signaling, redox perturbation, and metabolic reprogramming that may reveal targetable vulnerabilities at their intersection.

Environmental xenobiotics with genotoxic activity are carcinogenic. However, individual differences in the susceptibility to xenobiotic-induced breast cancer remain unclear. Since epigenetic modifications could control the expression of metabolic enzymes, our goal was to determine whether epigenome modulated metabolic networks determine susceptibility to xenobiotic-induced breast cancer. The effect of epigenetic background on predisposition to carcinogen 7,12-dimethylbenz(a)anthracene (DMBA)-induced breast cancer development and progression was assessed using the A^vy/a mouse model. In a randomized block design, 22 isogenic A^vy/a (8 yellow, 7 slightly mottled, 7 pseudoagouti) and 8 wild type non-agouti (a/a black) age matched female mice were subjected to DMBA (30 mg/kg per mouse weight) once a week for 6 weeks to induce breast cancer. Compared to pseudoagouti littermates, a significant decrease in tumour latency with increased tumour burden was observed in slightly mottled and yellow littermates (p ≤ 0.05). However, tumour latency and tumour burden were similar in non-agouti a/a mice and A^vy/a cohorts. Network analysis of differentially expressed liver genes identified altered metabolic gene networks among agouti phenotypes. Consequently, in HPLC analyses, DMBA metabolites were significantly increased in A^vy/a pseudoagouti mice (p ≤ 0.05). Relative to A^vy/a slightly mottled, A^vy/a yellow and non-agouti a/a black mice, DMBA metabolites increased nine-, eight-, and four-fold, respectively, in A^vy/a pseudoagouti mice. In agreement with this, seven phase 2 xenobiotic detoxification genes were significantly upregulated in A^vy/a pseudoagouti mice (p ≤ 0.05). The Results from this study suggest that epigenome modulation of xenobiotic detoxification pathways may control xenobiotic-induced breast cancer susceptibility in A^vy/a mice.

Head and neck squamous cell carcinoma (HNSCC) remains a clinically challenging malignancy with limited targeted therapy options and poor patient outcomes. Thus, identifying unique dependencies, including HNSCC-specific metabolic reprogramming, is imperative for improving treatment strategies for this disease. In this study, we show that HNSCC relies on elevated glucose transporter 1 (GLUT1)–mediated glucose uptake to support redox homeostasis and tumor growth. Analyses of GLUT1 expression data in tumors and cancer cell lines reveal significant upregulation of GLUT1 in HNSCC relative to both normal tissue and other cancer subtypes and that high GLUT1 expression correlates with poorer clinical outcomes. Using a basal epithelial layer–specific GLUT1-knockout mouse model, we demonstrate that GLUT1 ablation in HNSCC cells of origin markedly attenuates tumor initiation and progression, implicating the necessity of GLUT1 in HNSCC tumorigenesis. Building on this observation, combining pharmacologic inhibition of GLUT1 with pro-oxidants such as vitamin C and auranofin induces potent cytotoxicity in vitro and in vivo, partly by precipitating oxidative stress. We further observe that insulin signaling is required to sustain glucose uptake and redox homeostasis, as insulin receptor knockdown decreases proliferation and increases reactive oxygen species levels. Together, these results suggest that although GLUT1 overexpression is a key driver of glucose uptake, insulin signaling also contributes to the metabolic and oncogenic pathways underlying HNSCC progression. Consequently, strategies that co-target GLUT1 and insulin signaling to restrict glucose flux may synergize with pro-oxidant therapies, offering a promising therapeutic avenue for HNSCC. Significance: Enhanced GLUT1 expression and oncogenic insulin signaling drive elevated glucose uptake in HNSCC, which contribute to the maintenance of redox homeostasis and tumor growth. Disrupting both glucose uptake and redox balance may offer a promising therapeutic approach.

GLUT1 inhibition enhances cytotoxic oxidative stress in human HNSCC cell lines. A,In vitro proliferation and immunoblot analyses of shScramble (shScr) and shRNA-mediated KD of GLUT1 (shGLUT1) in HNSCC cell line FaDu (n = 4 for each group). Two-way ANOVA. ****, P < 0.0001 (left). Immunoblot validation of shRNA-mediated KD of GLUT1 in FaDu cells (right). B, Relative glucose uptake and (C) intracellular ROS measurement in shScr and shGLUT1 FaDu cells (n = 3 for each group). Two-tailed t test. ***, P < 0.001; **, P < 0.01. D,In vitro proliferation of shScr, shGLUT1, and shGLUT1 + NAC (5 mmol/L) in HNSCC cell line SCC-61 (n = 4 for each group). Two-way ANOVA. ****, P < 0.0001 (left). Immunoblot validation shRNA-mediated KD of GLUT1 in SCC-61 cells (right). E, Intracellular ROS measurement of shScr, shGLUT1, and shGLUT1 + NAC (5 mmol/L) in SCC-61 cells (n = 3 for each group). Two-tailed t test. ****, P < 0.0001; ***, P < 0.001. F and G,In vitro proliferation of FaDu cells treated with GLUT1 inhibitors, WZB117 (0–40 μmol/L) or BAY-876 (0–100 nmol/L; n = 3 for each group). H and I,In vitro proliferation of FaDu (H) or SCC-61 (I) treated with WZB117 (30 μmol/L) or BAY-876 (150 nmol/L) with or without 5 mmol/L NAC treatment (n = 6 for each group). Two-way ANOVA. ****, P < 0.0001; **, P < 0.01; *, P < 0.05 (top). Intracellular H2O2 measurement of FaDu (H) or SCC-61 (I) cells treated with WZB117 (30 μmol/L) or BAY-876 (150 nmol/L) with or without 5 mmol/L NAC treatment (n = 6 for each group). Two-tailed t test. ****, P < 0.0001; ***, P < 0.001; **, P < 0.01 (bottom). All error bars represent mean ± SEM unless otherwise noted. BAY, BAY-876; RFU, relative fluorescent unit; RLU, relative light unit; WZB, WZB117.