Inhibition of mTOR reduces anal carcinogenesis in transgenic mouse model

Advances in HPV-associated tumor management: Therapeutic strategies and emerging insights

With the rapid increase in the incidence of cervical cancer, anal cancer and other cancers, human papillomavirus (HPV) infection has become a growing concern. Persistent infection with high-risk HPV is a major cause of malignant tumors. In addition, microbiota and viruses such as human immunodeficiency virus, herpes simplex virus, and Epstein-Barr virus are closely associated with HPV infection. The limited effectiveness of existing treatments for HPV-associated tumors and the high rates of recurrence and metastasis in patients create an urgent need for novel and effective approaches. In recent years, HPV vaccine coverage has increased and can reduce the incidence of serious adverse events. Overall, this article provides a comprehensive overview of HPV biology, microbiome, and other viral interactions in cancer development, highlighting the need for a more comprehensive approach to cancer prevention and treatment. Current and emerging HPV-related cancer control and treatment strategies are also further explored.

Doublecortin-like kinase 1 is a therapeutic target in squamous cell carcinoma

Doublecortin like kinase 1 (DCLK1) plays a crucial role in several cancers including colon and pancreatic adenocarcinomas. However, its role in squamous cell carcinoma (SCC) remains unknown. To this end, we examined DCLK1 expression in head and neck SCC (HNSCC) and anal SCC (ASCC). We found that DCLK1 is elevated in patient SCC tissue, which correlated with cancer progression and poorer overall survival. Furthermore, DCLK1 expression is significantly elevated in human papilloma virus negative HNSCC, which are typically aggressive with poor responses to therapy. To understand the role of DCLK1 in tumorigenesis, we used specific shRNA to suppress DCLK1 expression. This significantly reduced tumor growth, spheroid formation, and migration of HNSCC cancer cells. To further the translational relevance of our studies, we sought to identify a selective DCLK1 inhibitor. Current attempts to target DCLK1 using pharmacologic approaches have relied on nonspecific suppression of DCLK1 kinase activity. Here, we demonstrate that DiFiD (3,5-bis [2,4-difluorobenzylidene]-4-piperidone) binds to DCLK1 with high selectivity. Moreover, DiFiD mediated suppression of DCLK1 led to G2/M arrest and apoptosis and significantly suppressed tumor growth of HNSCC xenografts and ASCC patient derived xenografts, supporting that DCLK1 is critical for SCC growth.

Research on Anal Squamous Cell Carcinoma: Systemic Therapy Strategies for Anal Cancer

Simple Summary

Anal cancer is rare with an estimated 9000 new cases predicted to occur in the United States in 2021. However, rates of new anal cancer cases and deaths from the disease are increasing by about 2% and 3% per year respectively. In light of these trends it is critical to better understand the nature of this disease and progress in its management. The present review focuses on the history and development of the role of systemic therapy in the treatment of anal cancer. Major trials establishing the role of chemotherapy in the management of locoregional and metastatic anal cancer are summarized. In addition, the rapidly evolving role of immunotherapy is discussed. Finally, major insights into the molecular pathobiology of anal cancer and opportunities for advancement in precision medicine in treatment of the disease.

Abstract

Anal squamous cell carcinoma (ASCC) is a rare malignancy, with most cases associated with human papilloma virus and an increased incidence in immunocompromised patients. Progress in management of ASCC has been limited not only due to its rarity, but also the associated lack of research funding and social stigma. Historically, standard of care for invasive ASCC has been highly morbid surgical resection, requiring a permanent colostomy. Surgery was associated with disease recurrence in approximately half of the patients. However, the use of chemotherapy (5-fluorouracil and mitomycin C) concomitantly with radiation in the 1970s resulted in disease regression, curing a subset of patients and sparing them from morbid surgery. Validation of the use of systemic therapy in prospective trials was not achieved until approximately 20 years later. In this review, advancements and shortcomings in the use of systemic therapy in the management of ASCC will be discussed. Not only will standard-of-care systemic therapies for locoregional and metastatic disease be reviewed, but the evolving role of novel treatment strategies such as immune checkpoint inhibitors, HPV-based vaccines, and molecularly targeted therapies will also be covered. While advances in ASCC treatment have remained largely incremental, with increased biological insight, an increasing number of promising systemic treatment modalities are being explored.

mTOR Signalling in Head and Neck Cancer: Heads Up

The mammalian target of rapamycin (mTOR) signalling pathway is a central regulator of metabolism in all cells. It senses intracellular and extracellular signals and nutrient levels, and coordinates the metabolic requirements for cell growth, survival, and proliferation. Genetic alterations that deregulate mTOR signalling lead to metabolic reprogramming, resulting in the development of several cancers including those of the head and neck. Gain-of-function mutations in EGFR, PIK3CA, and HRAS, or loss-of-function in p53 and PTEN are often associated with mTOR hyperactivation, whereas mutations identified from The Cancer Genome Atlas (TCGA) dataset that potentially lead to aberrant mTOR signalling are found in the EIF4G1, PLD1, RAC1, and SZT2 genes. In this review, we discuss how these mutant genes could affect mTOR signalling and highlight their impact on metabolic processes, as well as suggest potential targets for therapeutic intervention, primarily in head and neck cancer.

Experimental and investigational drugs for the treatment of anal cancer

INTRODUCTION

Squamous cell carcinoma of the anal canal (SCCA) is a rare malignancy, but its incidence rates have been increasing in the last decade. Studies have demonstrated that up to 47% of patients with locally advanced disease have high-risk features for treatment failure. The potential high rates of recurrence after standard chemoradiotherapy for locally advanced disease and the lack of established care for metastatic disease have created an urgent need for the evaluation of new drugs that will ultimately improve the efficacy of treatment.

AREAS COVERED

This review presents results of recent phase-I and -II clinical trials which evaluate novel therapeutic modalities. The review also describes the findings of comprehensive genomic profiling studies which provide insights for promising therapeutics.

EXPERT OPINION

HPV vaccination is underutilized in the United States and as a result, HPV-associated malignancies are likely to continue for several decades; however, pivotal breakthroughs may create a foundation for distinctive treatment approaches for other HPV-associated malignancies for which no other standard of care exists.

Targeting phosphorylation of STAT3 delays tumor growth in HPV-negative anal squamous cell carcinoma mouse model

Although conventional chemoradiotherapy is effective for most anal squamous cell carcinoma (ASCC) patients, HPV-negative ASCC patients respond poorly to this treatment and new therapeutic approach is required. Our group has previously established an HPV-negative ASCC mouse model and demonstrated that signal transducer and activation of transcription 3 (STAT3) is hyper-activated in the model. Here, we show that in vivo inhibition of STAT3 by S3I-201 effectively delays tumor growth in ASCC mouse model indicated by significantly smaller tumor size and burden in the treatment group compared with control group at the same point. Further analysis shows that survivin and Ki67, important biomarkers for tumor cell survival and proliferation, are significantly reduced after S3I-201 treatment. Additionally, flow cytometry and immunohistofluorescent assays reveal decreased Myeloid-derived suppressor cell (MDSC) and tumor-associated macrophage (TAM) populations in the S3I-201 treatment group, which indicates a reversion of the immunosuppressive environment, unraveling the potential role for S3I-201 in immunosuppression in ASCC. Together these results for the first time demonstrated the anti-tumor effects of STAT3 inhibitor S3I-201 in HPV-negative ASCC mouse model and its multiple effects on cancer cells and immune system. Thus we conclude that S3I-201 may be a novel therapeutic approach for HPV-negative ASCC patients.

Biomarkers in anal cancer: from biological understanding to stratified treatment

Squamous cell carcinomas of the anus and anal canal represent a model of a cancer and perhaps the first where level 1 evidence supported primary chemoradiotherapy (CRT) in treating locoregional disease with curative intent. The majority of tumours are associated with infection with oncogenic subtypes of human papilloma virus and this plays a significant role in their sensitivity to treatment. However, not all tumours are cured with CRT and there remain opportunities to improve outcomes in terms of oncological control and also reducing late toxicities. Understanding the biology of ASCC promises to allow a more personalised approach to treatment, with the development and validation of a range of biomarkers and associated techniques that are the focus of this review.

Mutational analysis of anal cancers demonstrates frequent PIK3CA mutations associated with poor outcome after salvage abdominoperineal resection

BACKGROUND

A better understanding of the molecular profile of anal squamous cell carcinomas (ASCCs) is necessary to consider new therapeutic approaches, and the identification of prognostic and predictive factors for response to treatment.

METHODS

We retrospectively analysed tumours from ASCC patients for mutational analysis of KRAS, NRAS, HRAS, BRAF, PIK3CA, MET, TP53 and FBXW7 genes by HRM and Sanger sequencing analysis.

RESULTS

Specimens from 148 patients were analysed: 96 treatment-naive tumours and 52 recurrences after initial radiotherapy (RT) or chemoradiotherapy (CRT). Mutations of KRAS, PIK3CA, FBXW7 and TP53 genes were present in 3 (2.0%), 30 (20.3%), 9 (6.1%) and 7 tumours (4.7%), respectively. The distribution of the mutations was similar between treatment-naive tumours and recurrences, except for TP53 mutations being more frequent in recurrences (P=0.0005). In patients treated with abdominoperineal resection (APR) after relapse (n=38, median follow-up of 18.2 years), overall survival (OS) was significantly correlated with HPV16 status (P=0.048), gender (P=0.045) and PIK3CA mutation (P=0.037). The PIK3CA status retained its prognostic significance in Cox multivariate regression analysis (P=0.025).

CONCLUSIONS

Our study identified PIK3CA mutation as an independent prognostic factor in patients who underwent APR for ASCC recurrence, suggesting a potential benefit from adjuvant treatment and the evaluation of targeted therapies with PI3K/Akt/mTor inhibitors in PIK3CA-mutated patients.

Immunocompromised and immunocompetent mouse models for head and neck squamous cell carcinoma

Mouse models can closely mimic human oral squamous epithelial carcinogenesis, greatly expand the in vivo research possibilities, and play a critical role in the development of diagnosis, monitoring, and treatment of head and neck squamous cell carcinoma. With the development of the recent research on the contribution of immunity/inflammation to cancer initiation and progression, mouse models have been divided into two categories, namely, immunocompromised and immunocompetent mouse models. And thus, this paper will review these two kinds of models applied in head and neck squamous cell carcinoma to provide a platform to understand the complicated histological, molecular, and genetic changes of oral squamous epithelial tumorigenesis.

Comprehensive multiplatform biomarker analysis of 199 anal squamous cell carcinomas

Anal squamous cell carcinoma (ASCC) is a rare, HPV-associated malignancy typically diagnosed in early stages and definitively treated with chemoradiation. In situations where patients exhibit metastatic or recurrent disease, treatment options are severely limited. In this study, molecular alterations were identified that could be used to aid in therapeutic decisions for patients with metastatic or recurrent anal squamous cell carcinoma. Specimens from patients with this cancer were tested via a multiplatform profiling service (Caris Life Sciences, Phoenix, AZ) consisting of gene sequencing, protein expression by immunohistochemistry, and gene amplification with in situ hybridization. Utilizing these techniques, novel treatment strategies that could be explored were identified, including potential benefit with anti-EGFR therapies, immune checkpoint inhibitors, topoisomerase inhibitors, and taxanes. The frequency of overexpression of proteins that mark resistance to chemotherapeutic drugs, such as MRP1 (chemotherapy efflux pump), ERCC1 (resistance to platinum-based chemotherapy), and thymidylate synthase (resistance to fluoropyrimidines) were also identified, suggesting a lack of benefit. This multiplatform strategy could be explored for its potential to generate a personalized treatment selection for patients with advanced ASCC, provide a guide for future therapeutic development for this cancer, and be extended to other rare cancer types as well.

Inhibition of survivin reduces HIF-1α, TGF-β1 and TFE3 in salivary adenoid cystic carcinoma

In the present study, we explored the expression and correlation of survivin with HIF-1α, TGF-β1 and TFE3 in adenoid cystic carcinoma (AdCC). The expression of survivin, HIF-1α, TGF-β1 and TFE3 was assessed by immunohistochemical staining of a tissue microarray containing tissue samples of normal salivary gland (NSG), pleomorphic adenoma (PA) and AdCC. Correlation analysis of these proteins revealed that increased survivin expression was associated with the overexpression of HIF-1α (P<0.001, r = 0.5599), TGF-β1 (P<0.001, r = 0.6616) and TFE3 (P<0.001, r = 0.7747). The expression of survivin, HIF-1α, TGF-β1 and TFE3 was not correlated with the pathological type of human AdCC (P>0.05). Selective inhibition of survivin by YM155 and siRNA significantly reduced human SACC-83 cell proliferation, with the corresponding decrease in expression of HIF-1α, TGF-β1 and TFE3. The data indicate that the overexpression of survivin in AdCC is related to HIF-1α, TGF-β1 and TFE3. We hypothesize from these findings that the inhibition of survivin may be a novel strategy for neoadjuvant chemotherapeutic and radiosensitive treatment of AdCC.