Metformin as a Therapeutic Target in Endometrial Cancers.

Endometrial cancer is the most common gynecologic malignancy in developed countries. Its increasing incidence is thought to be related in part to the rise of metabolic syndrome, which has been shown to be a risk factor for the development of hyperestrogenic and hyperinsulinemic states. This has consequently lead to an increase in other hormone-responsive cancers as well e.g., breast and ovarian cancer. The correlation between obesity, hyperglycemia, and endometrial cancer has highlighted the important role of metabolism in cancer establishment and persistence. Tumor-mediated reprogramming of the microenvironment and macroenvironment can range from induction of cytokines and growth factors to stimulation of surrounding stromal cells to produce energy-rich catabolites, fueling the growth, and survival of cancer cells. Such mechanisms raise the prospect of the metabolic microenvironment itself as a viable target for treatment of malignancies. Metformin is a biguanide drug that is a first-line treatment for type 2 diabetes that has beneficial effects on various markers of the metabolic syndrome. Many studies suggest that metformin shows potential as an adjuvant treatment for uterine and other cancers. Here, we review the evidence for metformin as a treatment for cancers of the endometrium. We discuss the available clinical data and the molecular mechanisms by which it may exert its effects, with a focus on how it may alter the tumor microenvironment. The pleiotropic effects of metformin on cellular energy production and usage as well as intercellular and hormone-based interactions make it a promising candidate for reprogramming of the cancer ecosystem. This, along with other treatments aimed at targeting tumor metabolic pathways, may lead to novel treatment strategies for endometrial cancer

Mutation signature analysis identifies increased mutation caused by tobacco smoke associated DNA adducts in larynx squamous cell carcinoma compared with oral cavity and oropharynx.

Squamous cell carcinomas of the head and neck (HNSCC) arise from mucosal keratinocytes of the upper aero-digestive tract. Despite a common cell of origin and similar driver-gene mutations which divert cell fate from differentiation to proliferation, HNSCC are considered a heterogeneous group of tumors categorized by site of origin within the aero-digestive mucosa, and the presence or absence of HPV infection. Tobacco use is a major driver of carcinogenesis in HNSCC and is a poor prognosticator that has previously been associated with poor immune cell infiltration and higher mutation numbers. Here, we study patterns of mutations in HNSCC that are derived from the specific nucleotide changes and their surrounding nucleotide context (also known as mutation signatures). We identify that mutations linked to DNA adducts associated with tobacco smoke exposure are predominantly found in the larynx. Presence of this class of mutation, termed COSMIC signature 4, is responsible for the increased burden of mutation in this anatomical sub-site. In addition, we show that another mutation pattern, COSMIC signature 5, is positively associated with age in HNSCC from non-smokers and that larynx SCC from non-smokers have a greater number of signature 5 mutations compared with other HNSCC sub-sites. Immunohistochemistry demonstrates a significantly lower Ki-67 proliferation index in size matched larynx SCC compared with oral cavity SCC and oropharynx SCC. Collectively, these observations support a model where larynx SCC are characterized by slower growth and increased susceptibility to mutations from tobacco carcinogen DNA adducts

Stromal Monocarboxylate Transporter MCT4 is a Poor Prognostic Factor in Squamous Cell Carcinoma

ABSTRACT Introduction: Monocarboxylate transporter 4 (MCT4) is the main exporter of lactate out of cells. It is also a critical component in the glycolytic metabolism of cancer cells. In this study, stromal MCT4 in oral SCC was correlated with risk of recurrence (ROR), extent of primary tumor (pT) and nodal metastasis (pN), perineural invasion (PNI), lymphovascular invasion (LVI), HPV status, extracapsular extension (ECE) and positive margin. Methods: Clinical data were collected for 86 consecutive patients with oral HNSCC. Tissue microarrays (TMA) were constructed from paraffin blocks of resection specimens and stained for MCT4. Immunohistochemistry (IHC) staining was assessed and quantified by digital image analysis with Aperio software. Using a co-localization algorithm we assessed the intensity of staining and the percentage of positive cells in the tumoral stromal cells. Correlations of MCT4 expression with clinicopathological features and survival were studied. Results: Increased IHC staining for MCT4 was strongly associated with an increased risk of recurrence, OR 1.96 (95%CI: 1.17-3.40), presence of PNI, OR 2.25 (95%CI: 1.33-3.95), higher pT, OR 1.68 (95%CI: 0.99-2.89), higher pN, OR 2.07 (95%CI: 1.25-3.57) and presence of LVI, OR 2.21 (95%CI: 1.11-4.67). We didn’t find any significant association between stromal MCT4 expression and HPV status, presence of ECE or positive margin. Conclusions: This study demonstrates that MCT4, a marker of glycolysis in cancer-associated stroma, is highly expressed in oral SCC. The IHC staining pattern of stromal MCT4 suggests that high MCT4 expression appears to be a useful marker for tumor progression and prognosis. We propose MCT4 serves as a new prognostic factor in oral SCC and can act as a potential therapeutic target marker considering pharmacological development of MCT4 inhibitors

Tumor Metabolism in the Microenvironment of Nodal Metastasis in Head and Neck Squamous Cell Carcinoma

ABSTRACT Introduction: Monocarboxylate transporter 4 (MCT4) is a cell membrane transporter of lactate. MCT4 is a tumor-specific marker of oxidative stress, glycolysis and hypoxia in tumor stromal cells. We investigated HPV positive and negative tumors with regional metastases to cervical lymph nodes (LN) to study how the metastatic tumor cells interact with their microenvironment. By selecting cancers with extracapsular extension (ECE), we intended to evaluate the interaction between metastases and the surrounding extranodal tissue. Methods: Clinical data were collected from 24 advanced stage oropharyngeal squamous cell carcinoma (OPSCC) patients with neck LN metastasis. All patients presented with at least N1 disease and had ECE. Sixteen cases were negative for HPV and eight were positive. Ten patients (42%) had ECE \u3c 1 mm, and 14 (58%) had ECE \u3e than 1 mm. The extent of ECE was quantified on H&E stains by distance from the edge of capsule. The paraffin-embedded metastatic LN sections were stained with MCT4 and quantification was accomplished using the Aperio Co-localization algorithm. Results: High stromal MCT4 expression was strongly associated with the extent of ECE regardless of HPV status (p=0.031). The stromal MCT4 expression in ECE area was significantly higher as opposed to the surrounding extranodal tissue adjacent to intact capsule (p\u3c0.001). We also found a borderline difference in expression of MCT4 in HPV- LN with ECE \u3e1mm vs. \u3c1mm(p=0.06). Conclusions: MCT4 is a marker of oxidative stress and higher expression of stromal MCT4 in ECE area is significantly correlated with the extent of ECE. The stromal cells separating nests of cancer cells in ECE area have apparent expression of the MCT4. Together these findings provide new insight into the critical role of stromal MCT4 in nodal metastasis and ECE in OPSCC and it may be useful to develop a novel prognostic marker and new anti-cancer agents

Tadalafil Enhances Immune Signatures in Response to Neoadjuvant Nivolumab in Resectable Head and Neck Squamous Cell Carcinoma

Purpose: We hypothesize that the addition of the phosphodiesterase-5 inhibitor tadalafil to the PD-1 inhibitor nivolumab, is safe and will augment immune-mediated antitumor responses in previously untreated squamous cell carcinoma of the head and neck (HNSCC). Patients and methods: We conducted a two-arm multi-institutional neoadjuvant randomized trial in any-stage resectable HNSCC (NCT03238365). Patients were stratified at randomization by human papillomavirus (HPV) status. Patients in both arms received nivolumab 240 mg intravenously on days 1 and 15 followed by surgery on day 28. Those in the combination therapy arm also received tadalafil 10 mg orally once daily for 4 weeks. Imaging, blood, and tumor were obtained pretreatment and posttreatment for correlative analysis. Results: Neoadjuvant therapy was well-tolerated with no grade 3 to 5 adverse events and no surgical delays. Twenty-five of 46 (54%) evaluable patients had a pathologic treatment response of ≥20%, including three (7%) patients with a complete pathologic response. Regardless of HPV status, tumor proliferation rate was a negative predictor of response. A strong pretreatment T-cell signature in the HPV-negative cohort was a predictor of response. Tadalafil altered the immune microenvironment, as evidenced by transcriptome data identifying enriched B- and natural killer cell gene sets in the tumor and augmented effector T cells in the periphery. Conclusions: Preoperative nivolumab ± tadalafil is safe in HNSCC and results in more than 50% of the patients having a pathologic treatment response of at least 20% after 4 weeks of treatment. Pretreatment specimens identified HPV status-dependent signatures that predicted response to immunotherapy while posttreatment specimens showed augmentation of the immune microenvironment with the addition of tadalafil