Highlighting the role of CD44 in cervical cancer progression: immunotherapy's potential in inhibiting metastasis and chemoresistance

Cervical cancer affects thousands of women globally with recurring high-risk HPV infections being at the centre of cervical pathology. Oncological treatment strategies are continually challenged by both chemoresistance and metastasis within patients. Although both work hand-in-hand, targeting their individual mechanisms could prove highly beneficial for treatment outcomes. Such targets include the metastatic-promoting stem cell marker, CD44, which is abundant in cervical cancer cells and is common to both chemoresistance and metastatic mechanisms. Seeing that many existing advanced-stage cervical cancer treatment regimes, such as platinum-based chemotherapy regimens, remain limited and are rarely curative, alternative treatment options within the field of immunology are being considered. The use of immune checkpoint inhibition therapy, which targets immune checkpoints, CTLA-4 and PD-1/PD-L1, has shown promise as an alternate standard of care for patients suffering from advanced-stage cervical cancer. Therefore, this review aims to assess whether immune checkpoint inhibition can mitigate the pathological effects of CD44-induced EMT, metastasis, and chemoresistance in cervical cancer patients.

Application of Immune Checkpoint Inhibitors in Gynecological Cancers: What Do Gynecologists Need to Know before Using Immune Checkpoint Inhibitors?

Standard treatments for gynecological cancers include surgery, chemotherapy, and radiation therapy. However, there are limitations associated with the chemotherapeutic drugs used to treat advanced and recurrent gynecological cancers, and it is difficult to identify additional treatments. Therefore, immune checkpoint inhibitor (ICI) therapy products, including PD-1/PD-L1 inhibitors and CTLA-4 inhibitors, are in the spotlight as alternatives for the treatment of advanced gynecological cancers. Although the ICI monotherapy response rate in gynecological cancers is lower than that in melanoma or non-small cell lung cancer, the response rates are approximately 13-52%, 7-22%, and 4-17% for endometrial, ovarian, and cervical cancers, respectively. Several studies are being conducted to compare the outcomes of combining ICI therapy with chemotherapy, radiation therapy, and antiangiogenesis agents. Therefore, it is critical to determine the mechanism underlying ICI therapy-mediated anti-tumor activity and its application in gynecological cancers. Additionally, understanding the possible immune-related adverse events induced post-immunotherapy, as well as the appropriate management of diagnosis and treatment, are necessary to create a quality environment for immunotherapy in patients with gynecological cancers. Therefore, in this review, we summarize the ICI mechanisms, ICIs applied to gynecological cancers, and appropriate diagnosis and treatment of immune-related side effects to help gynecologists treat gynecological cancers using immunotherapy.

Immuno-Oncology for Gynecologic Malignancies

Patients with advanced and/or recurrent gynecologic cancers derive limited benefit from currently available cytotoxic and targeted therapies. Successes of immunotherapy in other difficult-to-treat malignancies such as metastatic melanoma and advanced lung cancer have led to intense interest in clinical testing of these treatments in patients with gynecologic cancers. Currently, in the realm of gynecologic oncology, the FDA-approved use of immune checkpoint inhibitors is limited to microsatellite instability-high cancers, cancers with high tumor mutational burden, and PD-L1-positive cervical cancer. However, there has been an exponential growth of clinical trials testing immunotherapy approaches both alone and in combination with chemotherapy and/or targeted agents in patients with gynecologic cancers. This chapter will review some of the major reported and ongoing immunotherapy clinical trials in patients with endometrial, cervical, and epithelial ovarian cancer.

PD-L1: Can it be a biomarker for the prognosis or a promising therapeutic target in cervical cancer?

Cervical cancer is one of the most common in the female genital tract and remains a leading cause that threatens the health and lives of women worldwide, although preventive vaccines and early diagnosis have reduced mortality. While treatment by operation and chemoradiotherapy for early-stage patients achieve good outcomes, the great majority of cervical cancers caused by the human papilloma virus (HPV) make immunotherapy realizable for patients with advanced and recurrent cervical cancer. To date, some clinical trials of checkpoint immunotherapy in cervical cancer have indicated significant benefits of programmed cell death-1/programmed cell death-ligand 1 (PD-1/PD-L1) inhibitors, providing strong evidence for PD-1/PD-L1 as a therapeutic target. In this review article, we discuss the role of PD-L1 and the application of PD-L1 inhibitors in cervical cancer, with the aim of providing direction for future research.

Nanomedicine-mediated optimization of immunotherapeutic approaches in cervical cancer

Cervical cancer shows immense complexity at the epigenetic, genetic and cellular levels, limiting conventional treatment. Immunotherapy has revolutionized nanomedicine and rejuvenated the field of tumor immunology. Although several immunotherapeutic approaches have shown favorable clinical responses, their efficacies vary, with subsets of patients benefitting. The success of cancer immunotherapy requires the enhancement of cytokines and antitumor effector cell production and activation. Recently, the feasibility of nanoparticle-based cytokine approaches in tumor immunotherapy has been highlighted. Immunotherapeutic nanoparticle-based platforms form a novel strategy enabling researchers to co-deliver immunomodulatory agents, target tumors, improve pharmacokinetics and minimize collateral toxicity to healthy cells. This review looks at the potential of immunotherapy and nanotechnologically enhanced immunotherapeutic approaches for cervical cancer.

Immunotherapy and radiation therapy sequencing: State of the data on timing, efficacy, and safety

Radiation therapy exerts a tumoricidal local effect as well as both local and systemic immunomodulation. Immune checkpoint blockade has become a widely used treatment modality across cancer types with a rapidly growing list of agents and US Food and Drug Administration-approved indications. Moreover, there may be synergy between radiation therapy and immune checkpoint blockade. Various strategies have been used, but the optimal sequencing of these therapies is unclear. In this review, the authors discuss the major mechanisms of available immune checkpoint inhibitors and explore the available preclinical and clinical evidence regarding treatment sequencing. They also review safety considerations and conclude with possible future directions.

Immunotherapy and Its Development for Gynecological (Ovarian, Endometrial and Cervical) Tumors: From Immune Checkpoint Inhibitors to Chimeric Antigen Receptor (CAR)-T Cell Therapy

Gynecological tumors are malignancies with both high morbidity and mortality. To date, only a few chemotherapeutic agents have shown efficacy against these cancer types (only ovarian cancer responds to several agents, especially platinum-based combinations). Within this context, the discovery of immune checkpoint inhibitors has led to numerous clinical studies being carried out that have also demonstrated their activity in these cancer types. More recently, following the development of chimeric antigen receptor (CAR)-T cell therapy in hematological malignancies, this strategy was also tested in solid tumors, including gynecological cancers. In this article, we focus on the molecular basis of gynecological tumors that makes them potential candidates for immunotherapy. We also provide an overview of the main immunotherapy studies divided by tumor type and report on CAR technology and the studies currently underway in the area of gynecological malignancies.

Advances in immunotherapy for cervical cancer

PURPOSE OF REVIEW

Novel therapies are needed for the treatment of recurrent cervical cancer. The best chemotherapy regimen to date has a response rate of 48% with an overall survival of 17 months, with limited options for second-line chemotherapy. Immunotherapy can induce a strong immune response in cervical cancer due to retained viral antigens and is reviewed in this article.

RECENT FINDINGS

Current clinical trials include treatment with Listeria that elicits an immune response against the E7 oncoprotein and active vaccines against the E7 oncoprotein. Although the response rates to programmed cell death 1 (PD-1) inhibition alone have been modest, the landmark survival reported in these trials suggests the activity of these agents may not be measured by RECIST criteria. The KEYNOTE-158 trial has led to the approval of pembrolizumab in recurrent programmed cell death ligand 1 (PD-L1) positive cervical cancer. Combinations of programmed cell death 1 and anticytotoxic T-lymphocyte-associated protein 4 inhibitors (CTLA4) inhibitors have shown promising and durable activity. There is active research with new combinations of checkpoint inhibitors, as well as combinations of these drugs with chemotherapy and radiation, and other novel approaches.

SUMMARY

Immune therapy has broad activity in cervical cancer. Responses to immunotherapy can be dramatic and durable. Continued work to find the optimal combination and setting for immunotherapy is ongoing.

Recent developments in immunotherapy of cancers caused by human papillomaviruses

A subset of oncogenic human papillomaviruses (HPVs) is the main cause of genital cancers, most importantly cervical cancer and an increasing number of head and neck cancers. Despite the availability of prophylactic vaccines against the most prevalent oncogenic HPV types, HPV‐induced malignancies are still a major health and economic burden. Besides conventional treatment with surgery, chemotherapy and radiation, immunotherapy is emerging as an efficient adjuvant option. Here, we review relevant studies and ongoing clinical trials using immune checkpoint inhibitors, therapeutic vaccines, gene editing approaches and adoptive T cell therapies, with special focus on engineered TCR T cells, which are showing encouraging results and could lead to significant improvement in the treatment of HPV+‐infected cancer patients.

Comprehensive Analysis of the Relationships Between Tumor Mutation Burden With Immune Infiltrates in Cervical Cell Carcinoma

We aimed to investigate the prognosis of tumor mutation burden (TMB) in cervical cell carcinoma (CCC) and its potential association with tumor-infiltrating immune cells. The data from TCGA were analyzed, and higher TMB levels conferred high overall survival time, associated with higher T staging (p = 0.006) and older age (p = 2.961e−04). Through “CIBERSORT” package and Wilcoxon rank-sum test, the high TMB group exhibited higher levels of infiltration of T cell CD8 (p = 0.008), T cell CD4 memory activation (p = 0.006), T cell follicular assistance (p = 0.018), and Macrophage M1 (p = 0.037). In addition, 478 TMB-associated differentially expressed genes were identified, and two hub TMB-associated immune genes were identified, including CLEC3B and COL4A2. The TMB prognostic model (TMBPM) based on two hub immune genes showed robust prognostic capability in both training set and testing sets, and the higher the TMBPM score, the worse the prognosis. Finally, survival time was higher for high CLEC3B expression levels (p = 0.038) and lower for high COL4A2 expression levels (p = 0.033). Notably, there is an association between the expression of these two genes and immune infiltration in CCC. CLEC3B expression was most significantly positively correlated with B cells, CD4+ T cells, and Macrophage infiltration. COL4A2 expression was most significantly positively correlated with the presence of Macrophage and Dendritic cell infiltration. In addition, we observed that CLEC3B and COL4A carry mutations in multiple forms that normally suppress immune infiltration, including B cells, CD8+ T cells, and Macrophages.

Immunotherapy for Gynecologic Cancer: Current Applications and Future Directions

The role of the immune system in the development of cancer has been a subject of ongoing clinical investigation in recent years. Emerging data demonstrate that tumorigenesis resulting in ovarian, uterine, and cervical cancers is a consequence of impaired host immune responses to cancerous cells. Leveraging the immune system through the use of immune checkpoint inhibitors, therapeutic vaccine therapy, and adoptive cell transfer presents a profound opportunity to revolutionize cancer treatment. This review will encompass the role of the immune system in development of gynecologic cancers and highlight recent data regarding immunotherapy applications in ovarian, uterine, and cervical cancers.

Optimizing immunotherapy for gynecologic cancers

PURPOSE OF REVIEW

This review will provide an update on the most recent clinical developments in immuno-oncology in advanced gynecologic cancers and will also highlight ongoing studies in this field.

RECENT FINDINGS

Although immune checkpoint blockade (ICB) therapy is rapidly altering the treatment landscape in a myriad of solid tumors, the efficacy of ICB therapy with antibodies directed against CTLA-4, PD-1, and PD-L1 in advanced gynecologic cancers has been limited. The exception has been the PD-1 inhibitor pembrolizumab in microsatellite instability high (MSI-H) or mismatch repair-deficient (dMMR) advanced endometrial cancers, highlighted by the recent conditional approval of pembrolizumab in recurrent/metastatic PD-L1-positive cervical cancers and the accelerated approval of pembrolizumab and lenvatinib in microsatellite stable (MSS) or mismatch repair-proficient (pMMR) advanced endometrial cancer. The discovery of novel, rational ICB combinatorial approaches in advanced gynecologic cancers is highly warranted.

SUMMARY

Recent advances in the genomic characterization of gynecologic malignancies have informed clinical trial design. However, improved molecular and immunophenotypic biomarkers to more accurately identify patients who will most benefit from immunotherapeutic approaches are urgently needed. This is especially critical as we attempt to integrate immune-oncology agents, chemotherapy, targeted therapy, and radiation therapy in the management of gynecologic cancers.

Immuno-oncology for Gynecologic Malignancies

Patients with advanced and/or recurrent gynecologic cancers derive limited benefit from currently available cytotoxic and targeted therapies. Successes of immunotherapy in other difficult-to-treat malignancies such as metastatic melanoma and advanced lung cancer have led to intense interest in clinical testing of these treatments in patients with gynecologic cancers. Currently, in the realm of gynecologic oncology, the FDA-approved use of immune checkpoint inhibitors is limited to microsatellite instable cancers and PD-L1-positive cervical cancer. However, there has been an exponential growth of clinical trials testing immunotherapy approaches, both alone and in combination with chemotherapy and/or targeted agents, in patients with gynecologic cancers. This chapter reviews some of the major reported and ongoing immunotherapy clinical trials in patients with endometrial, cervical, and epithelial ovarian cancer.

Current Possibilities of Gynecologic Cancer Treatment with the Use of Immune Checkpoint Inhibitors

Despite the ongoing progress in cancer research, the global cancer burden has increased to 18.1 million new cases and 9.6 million deaths in 2018. Gynecological cancers, such as ovarian, endometrial, and cervical cancers, considerably contribute to global cancer burden, leading to $5,862.6, $2,945.7, and $1,543.9 million of annual costs of cancer care, respectively. Thus, the development of effective therapies against gynecological cancers is still a largely unmet medical need. One of the novel therapeutic approaches is to induce anti-cancer immunity by the inhibition of the immune checkpoint pathways using monoclonal antibodies. The molecular targets for monoclonal antibodies are cytotoxic T lymphocyte-associated protein-4 (CTLA-4), programmed cell death protein-1 (PD-1), and programmed death-ligand 1 (PD-L1). The rationale for the use of immune checkpoint inhibitors in patients with gynecological cancers was based on the immunohistological studies showing high expression levels of PD-1 and PD-L1 in those cancers. Currently available immune checkpoint inhibitors include nivolumab, pembrolizumab, atezolizumab, avelumab, durvalumab, and ipilimumab. The efficacy and safety of these inhibitors, used as monotherapy and with combination with chemotherapy, is being currently evaluated in several clinical studies. As the results are promising, more clinical trials are being planned, which may lead to the development of efficient therapies for gynecological cancer patients.

Immunotherapy for Uterine Cervical Cancer

Cervical cancer is a malignant neoplastic disease that is the fourth most commonly occurring cancer in women worldwide. Since the introduction of angiogenesis inhibitors, treatments for recurrent and advanced cervical cancers have improved significantly in the past five years. However, the median overall survival in advanced cervical cancer is 16.8 months, with a 5-year overall survival rate of 68% for all stages, indicating that the effects of the treatment are still unsatisfactory. The development of a new treatment method is therefore imperative. Recently, in the clinical oncology field, remarkable progress has been made in immunotherapy. Immunotherapy is already established as standard therapy in some fields and in some types of cancers, and its clinical role in all areas, including the gynecology field, will change further based on the outcomes of currently ongoing clinical trials. This manuscript summarizes the results from previous clinical trials in cervical cancer and describes the ongoing clinical trials, as well as future directions.

Combination Immune Checkpoint Blockade Strategies to Maximize Immune Response in Gynecological Cancers

PURPOSE OF REVIEW

Immune checkpoint blockade targeting PD-1 and PD-L1 improves immune recognition of tumor cells but had only modest success in gynecological cancers as monotherapy. Growing focus has been placed on combination immunotherapy strategies to overcome this resistance, and this review serves to discuss some of the most promising studies in gynecological cancers.

RECENT FINDINGS

PD-1- and PD-L1-targeting antibodies are being combined with many novel agents including anti-CTLA-4 antibodies, PARP inhibitors, targeted agents, and traditional chemotherapy in promising studies with the hopes of increasing the immune response and overcoming resistance by targeting other pathways. Novel immune techniques including vaccines and adoptive cell therapies are also being implemented in gynecological cancers. Immune checkpoint combinations and novel immunotherapy strategies have demonstrated potential to overcome resistance to PD-1/PD-L1 blockade in gynecological cancers. Identification of biomarkers of response and resistance is a priority to tailor specific combination therapies to the appropriate patients.

The current status of immunotherapy for cervical cancer

Immunotherapy has been proven effective in several tumours, hence diverse immune checkpoint inhibitors are currently licensed for the treatment of melanoma, kidney cancer, lung cancer and most recently, tumours with microsatellite instability. There is much enthusiasm for investigating this approach in gynaecological cancers and the possibility that immunotherapy might become part of the therapeutic landscape for gynaecological malignancies. Cervical cancer is the fourth most frequent cancer in women worldwide and represents 7.9% of all female cancers with a higher burden of the disease and mortality in low- and middle-income countries. Cervical cancer is largely a preventable disease, since the introduction of screening tests, the recognition of the human papillomavirus (HPV) as an etiological agent, and the subsequent development of primary prophylaxis against high risk HPV subtypes. Treatment for relapsed/advanced disease has improved over the last 5 years, since the introduction of antiangiogenic therapy. However, despite advances, the median overall survival for advanced cervical cancer is 16.8 months and the 5-year overall survival for all stages is 68%. There is a need to improve outcomes and immunotherapy could offer this possibility. Clinical trials aim to understand the best timing for immunotherapy, either in the adjuvant setting or recurrent disease and whether immunotherapy, alone or in combination with other agents, improves outcomes.

Rational design for cervical cancer therapeutics: cellular and non-cellular based strategies on the horizon for recurrent, metastatic or refractory cervical cancer

INTRODUCTION

Though cervical cytology, HPV DNA testing, and pre-invasive disease management has significantly reduced the number of new diagnoses of cervical cancer, women with persistent oncogenic HPV infection are at significant risk for developing invasive cervical cancer. Early stage and locally advanced disease can be cured, but women with advanced or recurrent disease have a very poor prognosis. This underscores the need for different treatment strategies for advanced cervical cancer, the most promising of which are novel therapeutics that target the ability of HPV to overcome host immune tolerance. Areas covered: This review includes new therapies being investigated for the treatment of recurrent, metastatic or refractory cervical cancer, separated into broad categories of cellular and non-cellular based strategies. Expert opinion: Advanced and recurrent cervical cancer has a poor prognosis, prompting investigations into the development of strategies that will eradicate tumor and/or overcome host immunologic tolerance of disease. It is unknown whether it will be these strategies alone or a combination of treatment modalities that will ultimately provide the best outcomes; nevertheless, the new data are promising.