PI3k inhibitors (BKM120 and BYL719) as radiosensitizers for head and neck squamous cell carcinoma during radiotherapy

Telaglenastat as an alternative to cisplatin as a radiosensitizer in the treatment of head and neck squamous cell carcinoma

The efficacy of radiation treatment (RT) of head and neck squamous cell carcinoma (HNSCC) is limited by radioresistance and the toxicity of FDA approved radiosensitizers. In extension to our previous research where we demonstrated that telaglenastat (CB839) increased efficacy of RT in in vitro and in vivo HNSCC models, here, we examine the radiosensitizing effects of telaglenastat in comparison to cisplatin's, as cisplatin is currently the standard of care for concurrent therapy. Combination of telaglenastat with RT reduced tumor volume in a HNSCC patient derived xenograft mouse model. The efficacy of telaglenastat with RT in reducing cell survival and increasing apoptosis was similar if not greater than that of cisplatin with RT in Cal27 and HN5 HNSCC cells. The addition of telaglenastat increased reactive oxygen species and reduced the antioxidant glutathione in both Cal27 and HN5 cells. Reverse Phase Protein Array analyses revealed alterations in cell death and DNA damage response proteins. This study provides the scientific underpinnings for the use of telaglenastat as a radiosensitizer in the treatment of HNSCC either as an alternative to cisplatin or in cisplatin-ineligible patients.

Combinatorial Approaches for Chemotherapies and Targeted Therapies With Radiation: United Efforts to Innovate in Patient Care

Combinatorial therapies consisting of radiation therapy (RT) with systemic therapies, particularly chemotherapy and targeted therapies, have moved the needle to augment disease control across nearly all disease sites for locally advanced disease. Evaluating these important combinations to incorporate more potent therapies with RT will aid our understanding of toxicity and efficacy for patients. This article discusses multiple disease sites and includes a compilation of contributions from expert Red Journal editors from each disease site. Leveraging improved systemic control with novel agents, we must continue efforts to study novel treatment combinations with RT.

Panoramic view of key cross-talks underpinning the oral squamous cell carcinoma stemness - unearthing the future opportunities

The clinical management of oral cancer is often frequented with challenges that arise from relapse, recurrence, invasion and resistance towards the cornerstone chemo and radiation therapies. The recent conceptual advancement in oncology has substantiated the role of cancer stem cells (CSC) as a predominant player of these intricacies. CSC are a sub-group of tumor population with inherent adroitness to self-renew with high plasticity. During tumor evolution, the structural and functional reprogramming persuades the cancer cells to acquire stem-cell like properties, thus presenting them with higher survival abilities and treatment resistance. An appraisal on key features that govern the stemness is of prime importance to confront the current challenges encountered in oral cancer. The nurturing niche of CSC for maintaining its stemness characteristics is thought to be modulated by complex multi-layered components encompassing neoplastic cells, extracellular matrix, acellular components, circulatory vessels, various cascading signaling molecules and stromal cells. This review focuses on recapitulating both intrinsic and extrinsic mechanisms that impart the stemness. There are contemplating evidences that demonstrate the role of transcription factors (TF) in sustaining the neoplastic stem cell's pluripotency and plasticity alongside the miRNA in regulation of crucial genes involved in the transformation of normal oral mucosa to malignancy. This review illustrates the interplay between miRNA and various known TF of oral cancer such as c-Myc, SOX, STAT, NANOG and OCT in orchestrating the stemness and resistance features. Further, the cross-talks involved in tumor micro-environment inclusive of cytokines, macrophages, extra cellular matrix, angiogenesis leading pathways and influential factors of hypoxia on tumorigenesis and CSC survival have been elucidated. Finally, external factorial influence of oral microbiome gained due to the dysbiosis is also emphasized. There are growing confirmations of the possible roles of microbiomes in the progression of oral cancer. Given this, an attempt has been made to explore the potential links including EMT and signaling pathways towards resistance and stemness. This review provides a spectrum of understanding on stemness and progression of oral cancers at various regulatory levels along with their current therapeutic knowledge. These mechanisms could be exploited for future research to expand potential treatment strategies.

Synergistic therapeutic potential of alpelisib in cancers (excluding breast cancer): Preclinical and clinical evidences

The phosphoinositide 3-kinase (PI3K) signaling pathway is well-known for its important role in cancer growth, proliferation and migration. The activation of PI3K pathway is always connected with endocrine resistance and poor prognosis in cancers. Alpelisib, a selective inhibitor of PI3K, has been demonstrated to be effective in combination with endocrine therapy in HR+ PIK3CA-mutated advanced breast cancer in preclinical and clinical trials. Recently, the synergistic effects of alpelisib combined with targeted agents have been widely reported in PIK3CA-mutated cancer cells, such as breast, head and neck squamous cell carcinoma (HNSCC), cervical, liver, pancreatic and lung cancer. However, previous reviews mainly focused on the pharmacological activities of alpelisib in breast cancer. The synergistic therapeutic potential of alpelisib in other cancers has not yet been well reviewed. In this review, an extensive study of related literatures (published until December 20, 2022) regarding the anti-cancer functions and synergistic effects of alpelisib was carried out through the databases. Useful information was extracted. We summarized the preclinical and clinical studies of alpelisib in combination with targeted anti-cancer agents in cancer treatment (excluding breast cancer). The combinations of alpelisib and other targeted agents significantly improved the therapeutic efficacy both in preclinical and clinical studies. Unfortunately, synergistic therapies still could not effectively avoid the possible toxicities and adverse events during treatment. Finally, some prospects for the combination studies in cancer treatment were provided in the paper. Taken together, this review provided valuable information for alpelisib in preclinical and clinical applications.

Selective Inhibition of PI3K Isoforms in Brain Tumors Suppresses Tumor Growth by Increasing Radiosensitivity

PURPOSE

Glioblastoma (GBM) is a malignant brain tumor with poor prognosis. Radioresistance is a major challenge in the treatment of brain tumors. The development of several types of tumors, including GBM, involves the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway. Upon activation, this pathway induces radioresistance. In this study, we investigated whether additional use of selective inhibitors of PI3K isoforms would enhance radiosensitivity in GBM.

MATERIALS AND METHODS

We evaluated whether radiation combined with PI3K isoform selective inhibitors can suppress radioresistance in GBM. Glioma 261 expressing luciferase (GL261-luc) and LN229 were used to confirm the effect of combination of radiation and PI3K isoform inhibitors in vitro. Cell viability was confirmed by clonogenic assay, and inhibition of PI3K/AKT signaling activation was observed by Western blot. To confirm radiosensitivity, the expression of phospho-γ-H2AX was observed by immunofluorescence. In addition, to identify the effect of a combination of radiation and PI3K-α isoform inhibitor in vivo, an intracranial mouse model was established by implanting GL261-luc. Tumor growth was observed by IVIS imaging, and survival was analyzed using Kaplan-Meier survival curves.

RESULTS

Suppression of the PI3K/AKT signaling pathway increased radiosensitivity, and PI3K-α inhibition had similar effects on PI3K-pan inhibition in vitro. The combination of radiotherapy and PI3K-α isoform inhibitor suppressed tumor growth and extended survival in vivo.

CONCLUSION

This study verified that PI3K-α isoform inhibition improves radiosensitivity, resulting in tumor growth suppression and extended survival in GBM mice.

Potential Alternative Therapeutic Modalities for Management Head and Neck Squamous Cell Carcinoma: A Review

Head and neck squamous cell carcinoma (HNSCC) includes malignancies of the lip and oral cavity, oropharynx, nasopharynx, larynx, and hypopharynx. It is among the most common malignancy worldwide, affecting nearly 1 million people annually. The traditional treatment options for HNSCC include surgery, radiotherapy, and conventional chemotherapy. However, these treatment options have their specific sequelae, which produce high rates of recurrence and severe treatment-related disabilities. Recent technological advancements have led to tremendous progress in understanding tumor biology, and hence the emergence of several alternative therapeutic modalities for managing cancers (including HNSCC). These treatment options are stem cell targeted therapy, gene therapy, and immunotherapy. Therefore, this review article aims to provide an overview of these alternative treatments of HNSCC.

Recommendations for the use of biomarkers for head and neck cancer, including salivary gland tumours: A Consensus of the Spanish Society of Medical Oncology and the Spanish Society of Pathology

The treatment of head and neck and salivary gland tumours is complicated and is constantly evolving. Prognostic and predictive indicators of response to treatment are enormously valuable for designing individualized therapies, which justifies their research and validation. Some biomarkers, such as p16, Epstein-Barr virus, PD-L1, androgen receptors and HER-2, are already used routinely in clinical practice. These biomarkers, along with other markers that are currently under development, and the massively parallel sequencing of genes, ensure future advances in the treatment of these neoplasms. In this consensus, a group of experts in the diagnosis and treatment of tumours of the head and neck and salivary glands were selected by the Spanish Society of Pathology (Sociedad Española de Anatomía Patológica - SEAP) and the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica - SEOM) to evaluate the currently available information and propose a series of recommendations to optimize the determination and daily clinical use of biomarkers.

Targeting PI3K/AKT/mTOR Signaling Pathway as a Radiosensitization in Head and Neck Squamous Cell Carcinomas

Globally, there are over half a million new patients with head and neck squamous cell carcinomas (HNSCC) every year. The current therapeutic approaches to HNSCC are surgery and adjuvant radiotherapy. These approaches carry a high incidence of metastasis or recurrence from HNSCC cells' radioresistance. Recent studies have revealed that a combination with radiosensitizers can be used to improve the radioresistance in HNSCC; however, few agents are approved as radiosensitizers. The constitutive activation of phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is a vitally oncogenic type of signaling that promotes tumorigenesis, metastasis, and radiotherapy resistance in HNSCC. Pharmacological targeting of PI3K/AKT/mTOR signaling pathway is considered a promising strategy of radiosensitization in HNSCC. In this review, we summarize the oncogenic significance of PI3K/AKT/mTOR signaling in HNSCC with radiotherapy resistance and highlight the therapeutic potential of small molecule inhibitors against PI3K/AKT/mTOR signaling for the radiosensitization in HNSCC treatment. It provides a mechanistic framework for the development of new drugs for radiosensitization in HNSCC radiotherapy via targeting PI3K/AKT/mTOR signaling pathway.

Recommendations for the use of biomarkers for head and neck cancer, including salivary gland tumours: a consensus of the Spanish Society of Medical Oncology and the Spanish Society of Pathology

The treatment of head and neck and salivary gland tumours is complicated and evolves constantly. Prognostic and predictive indicators of response to treatment are enormously valuable for designing individualized therapies, which justifies their research and validation. Some biomarkers, such as p16, Epstein-Barr virus, PD-L1, androgen receptors and HER-2, are already used routinely in clinical practice. These biomarkers, along with other markers that are currently under development, and the massively parallel sequencing of genes, ensure future advances in the treatment of these neoplasms. In this consensus, a group of experts in the diagnosis and treatment of tumours of the head and neck and salivary glands were selected by the Spanish Society of Pathology (Sociedad Española de Anatomía Patológica-SEAP) and the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica-SEOM) to evaluate the currently available information and propose a series of recommendations to optimize the determination and daily clinical use of biomarkers.

KRAS as a Key Oncogene in the Clinical Precision Diagnosis and Treatment of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors, with a 5-year survival rate of less than 10%. At present, the comprehensive treatment based on surgery, radiotherapy and chemotherapy has encountered a bottleneck, and targeted immunotherapy turns to be the direction of future development. About 90% of PDAC patients have KRAS mutations, and KRAS has been widely used in the diagnosis, treatment, and prognosis of PDAC in recent years. With the development of liquid biopsy and gene testing, KRAS is expected to become a new biomarker to assist the stratification and prognosis of PDAC patients. An increasing number of small molecule inhibitors acting on the KRAS pathway are being developed and put into the clinic, providing more options for PDAC patients.

Integrating radiation therapy with targeted treatments for breast cancer: From bench to bedside

Major advances have been made in precision medicine of breast cancer patients with a series of molecular targeted therapies now in clinical use or in late clinical development. These new therapeutic measures need to be integrated with local treatments, particularly with radiation therapy in both curative and advanced settings. Although a synergistic effect could be obtained between targeted therapies and irradiation, potential safety concerns should be carefully considered. At present, scarce evidence exists due to a lack of quality assurance on radiation therapy in pivotal trials of new drugs and missing reports on safety in case of concurrent radiation therapy, commonly administered with heterogenous doses and fractionations, especially in advanced disease. A major contribution for effectively combining radiation and targeted therapies in breast cancer could derive from clinically relevant preclinical studies. This review integrates preclinical and clinical evidence on how targeted agents and radiation therapy could be combined to help physicians in their daily clinical practice and to improve the clinical management of patients.

PI3Kδ/γ inhibitor BR101801 extrinsically potentiates effector CD8+ T cell-dependent antitumor immunity and abscopal effect after local irradiation

BACKGROUND

Radiotherapy enhances antitumor immunity. However, it also induces immunosuppressive responses, which are major hurdles for an effective treatment. Thus, targeting the immunosuppressive tumor microenvironment is essential for enhancing the antitumor immunity after radiotherapy. Retrospective studies show that a blockade of PI3Kδ and/or γ, which are abundant in leukocytes, exhibits antitumor immune response by attenuating activity of immune suppressive cells, however, the single blockade of PI3Kδ or γ is not sufficient to completely eliminate solid tumor.

METHODS

We used BR101801, PI3Kδ/γ inhibitor in the CT-26 syngeneic mouse model with a subcutaneously implanted tumor. BR101801 was administered daily, and the target tumor site was locally irradiated. We monitored the tumor growth regularly and evaluated the immunological changes using flow cytometry, ELISpot, and transcriptional analysis.

RESULTS

This study showed that BR101801 combined with irradiation promotes systemic antitumor immunity and abscopal response by attenuating the activity of immune suppressive cells in the CT-26 tumor model. BR101801 combined with irradiation systemically reduced the proliferation of regulatory T cells (Tregs) and enhanced the number of tumor-specific CD8α⁺ T cells in the tumor microenvironment, thereby leading to tumor regression. Furthermore, the high ratio of CD8α⁺ T cells to Tregs was maintained for 14 days after irradiation, resulting in remote tumor regression in metastatic lesions, the so-called abscopal effect. Moreover, our transcriptomic analysis showed that BR101801 combined with irradiation promoted the immune-stimulatory tumor microenvironment, suggesting that the combined therapy converts immunologically cold tumors into hot one.

CONCLUSIONS

Our data suggest the first evidence that PI3Kδ/γ inhibition combined with irradiation promotes systemic antitumor immunity against solid tumors, providing the preclinical result of the potential use of PI3Kδ/γ inhibitor as an immune-regulatory radiosensitizer.

PIK3CA Mutations Drive Therapeutic Resistance in Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer

The phosphatidylinositol 3-kinase (PI3K) pathway is an intracellular pathway activated in response to progrowth signaling, such as human epidermal growth factor receptor 2 (HER2) and other kinases. Abnormal activation of PI3K has long been recognized as one of the main oncogenic drivers in breast cancer, including HER2-positive (HER2+) subtype. Somatic activating mutations in the gene encoding PI3K alpha catalytic subunit (PIK3CA) are present in approximately 30% of early-stage HER2+ tumors and drive therapeutic resistance to multiple HER2-targeted agents. Here, we review currently available agents targeting PI3K, discuss their potential role in HER2+ breast cancer, and provide an overview of ongoing trials of PI3K inhibitors in HER2+ disease. Additionally, we review the landscape of PIK3CA mutational testing and highlight the gaps in knowledge that could present potential barriers in the effective application of PI3K inhibitors for treatment of HER2+ breast cancer.

Radiotherapy as a tool to elicit clinically actionable signalling pathways in cancer

A variety of targeted anticancer agents have been successfully introduced into clinical practice, largely reflecting their ability to inhibit specific molecular alterations that are required for disease progression. However, not all malignant cells rely on such alterations to survive, proliferate, disseminate and/or evade anticancer immunity, implying that many tumours are intrinsically resistant to targeted therapies. Radiotherapy is well known for its ability to activate cytotoxic signalling pathways that ultimately promote the death of cancer cells, as well as numerous cytoprotective mechanisms that are elicited by cellular damage. Importantly, many cytoprotective mechanisms elicited by radiotherapy can be abrogated by targeted anticancer agents, suggesting that radiotherapy could be harnessed to enhance the clinical efficacy of these drugs. In this Review, we discuss preclinical and clinical data that introduce radiotherapy as a tool to elicit or amplify clinically actionable signalling pathways in patients with cancer.