Rapamycin Induces Phenotypic Alterations in Oral Cancer Cells That May Facilitate Antitumor T Cell Responses

OBJECTIVES

In this study, we investigated the antitumor immunomodulatory effects of rapamycin in oral cancer.

STUDY DESIGN

We examined the proliferation, apoptosis, and migration of cancer cells and investigated the cell surface expression levels of immune accessory molecules and T cell immune responses in vitro. We investigated the effect of in vivo administration of rapamycin on immune cell distribution and T cell immune responses in oral tumor-bearing mice.

RESULTS

Rapamycin treatment significantly inhibited OSCC cell proliferation and migration, increased apoptotic cell death, and upregulated cell surface expression of several immune accessory and adhesion molecules, including CD40, CD83, PD-L1, PD-L2, MHC class I, P-selectin, and VCAM-1. These cancer cells augmented T cell proliferation. In vivo rapamycin administration significantly attenuated mouse tumor growth with an increased proportion of immune cells, including CD4+ T cells, CD8+ T cells, and dendritic cells (DCs); decreased the proportion of immune suppressive cells, such as myeloid-derived suppressor cells and regulatory T cells; enhanced DC maturation and upregulated the surface expression of CD40, CD86, and ICAM-1.

CONCLUSIONS

Our results suggest that the therapeutic effect of mTOR inhibition in oral cancer can cause direct antitumor and immunomodulatory effects.

Successful treatment with nivolumab in a patient with unresectable oral squamous cell carcinoma following ineffective chemoradiotherapy

Key clinical message

Nivolumab has been clinically successful in prolonging the overall survival of patients with recurrent and metastatic head and neck cancer, complete remission is rare. Synergistic combinations of immunotherapy and conventional cancer treatments, such as radiotherapy or chemotherapy, are likely to be the most viable strategies for improving patient responses.

Abstract

Immune checkpoint inhibitors have revolutionized recurrent, metastatic oral cancer treatment; however complete remission in advanced stages is unusual. We present a case of complete remission of advanced oral squamous cell carcinoma for >4 years in a 64-year-old Japanese woman, that responded poorly to chemoradiotherapy but well to subsequent nivolumab treatment.

Complete Response to Cetuximab Plus Paclitaxel Therapy in Nivolumab-Refractory Patients in Distant Metastasis of Squamous Cell Carcinoma of the Tongue: A Report of Two Cases

Herein, we report two cases of patients diagnosed with nivolumab-refractory distant metastatic squamous cell carcinoma of the tongue who were successfully treated with a combination of paclitaxel and cetuximab. Case 1 had controllable local recurrence and distant metastasis. Case 2 had controllable distant metastatic disease. Thus, demonstrating that some nivolumab-refractory patients with recurrent or distant metastatic oral squamous cell carcinoma may benefit from subsequent salvage chemotherapy.

Treatment of severe micrognathia in an adult with distraction osteogenesis: A case report

Key Clinical Message

Distraction osteogenesis (DO) of the mandible is often performed at a young age, and there are few reports after age 30, as in this case. The Hybrid MMF used in this case was useful in that it allowed correction of fine directionality.

Abstract

DO is often performed in young patients with a high capability of osteogenesis. We performed distraction surgery for a 35-year-old man who had severe micrognathia with serious sleep apnea syndrome. Four years postoperatively, suitable occlusion and improvement of apnea were observed.

Neutrophil-to-lymphocyte ratio as an early marker of outcomes in patients with recurrent oral squamous cell carcinoma treated with nivolumab: a pilot study

The immune checkpoint inhibitor (ICI), nivolumab, has revolutionised the treatment of recurrent and metastatic oral cancer. However, the response rate to ICIs remains low, and identifying predictors of nivolumab response is critical. Although the neutrophil-to-lymphocyte ratio (NLR) has been suggested as a predictive marker of nivolumab response in patients with various types of cancer, its utility in oral squamous cell carcinoma (OSCC) has not been elucidated. In this retrospective multicentre cohort study, we evaluated the association between NLR and outcome of nivolumab treatment in 64 patients with OSCC treated between 2017 and 2020. The objective response and disease control rates were 25.1% and 32.9%, respectively. The rates for complete and partial responses were 15.7% (10/64) and 9.4% (6/64), respectively; stable and progressive disease rates were 7.8% (5/64) and 67.1% (43/64), respectively. Complete and partial responses were classified as responders, and stable and progressive diseases were classified as non-responders. The median (range) pre-treatment NLR among responders was 4.3 (2.8-8.0), which decreased to 4.0 (2.6-6.3) after nivolumab treatment, and the median (range) pre-treatment NLR among non-responders was 5.1 (2.7-7.9), which increased to 6.4 (4.0-14.0) with tumour growth. Moreover, overall survival was significantly worse in the group with a higher post-treatment NLR (≥5) than in the group with a lower NLR (<5). Patients with a post-treatment NLR of ≥6 had worse outcomes for salvage chemotherapy following nivolumab treatment. Thus, post-treatment NLR could be a useful marker for predicting the response to nivolumab treatment or salvage chemotherapy in patients with OSCC.

[Neutrophil-to-Lymphocyte Ratio(NLR)as a Predictive Indicator of the Response to Nivolumab in Patients with Oral Squamous Cell Carcinoma]

BACKGROUND

The immune checkpoint inhibitor (ICI) nivolumab has revolutionized the treatment for recurrent or metastatic advanced oral cancer. Because the response rate remains low, the identification of predictive indicators of the response to nivolumab is among the most critical issues. The neutrophil-to-lymphocyte ratio(NLR)is a potential predictive marker of the response to nivolumab in patients with various cancer types. However, the utility of the NLR as a biomarker for predicting the response of oral cancer patients to ICIs is poorly understood.

PATIENTS AND METHODS

In this retrospective cohort study, we evaluated the association between NLR and nivolumab treatment outcome in 13 patients diagnosed with recurrent or metastatic oral squamous cell carcinoma(OSCC)treated with nivolumab at the Toyama University Hospital between December 2017 and December 2019.

RESULTS

Complete response(CR)and partial response(PR)rates of 38.5%(5/13)and 0% (0/13), respectively, were observed in responders; stable disease(SD)and progressive disease(PD)rates of 7.7%(1/13) and 53.8%(7/13), respectively, were observed in non-responders. After nivolumab treatment, the median NLR among responders decreased to 3.3(3.0-3.9)from 4.1(3.7-4.3)during pre-treatment assessment and increased from 5.6(3.2- 9.2)at pre-treatment to 9.4(5.3-17.9)among non-responders. Moreover, patients with higher NLRs(≥5)in the post- treatment group had a significantly worse overall survival than those with lower NLRs(<5). Specifically, patients with a higher post-treatment NLR(≥10)had significantly worse outcomes for post-nivolumab salvage chemotherapy.

CONCLUSION

The NLR could be a useful marker for predicting the treatment response to nivolumab or post-nivolumab salvage chemotherapy in OSCC patients.

Novel strategy to predict high risk of inferior alveolar nerve injury during extraction of lower third molars based on assessment of computed tomographic images of multiple anatomical features

Preoperative assessment is essential to prevent inferior alveolar nerve (IAN) injury during surgical extraction of the lower third molar (LM3). Here, we aimed to establish an assessment system to predict IAN injury during surgical extraction of the LM3. We conducted a retrospective cohort study on 115 patients diagnosed as 'high-risk' based on our previous risk assessment method involving three anatomical features of the inferior alveolar canal using computed tomographic (CT) images. We evaluated the occurrence of neurosensory impairment in these high-risk patients, and its association with novel anatomic features based on CT images. Neurosensory impairments were observed in 19 patients (16.5%). The inferior alveolar canal major diameter (p < 0.0001) and lingual bone thickness (p = 0.0039) were significantly associated with the occurrence of neurosensory impairment during LM3 extraction. Receiver operating characteristic curves were used to determine cut-off values of these quantitative factors to specifically predict IAN injury. Preoperative risk assessment with quantitative factors based on anatomical features observed on CT images may facilitate more appropriate surgical planning for patients at a high risk of IAN injury.

Central mucoepidermoid carcinoma of the maxilla developing from a calcifying odontogenic cyst: A rare case report

Intraosseous mucoepidermoid carcinoma of the jaw is a rare lesion that has been suggested to originate from the odontogenic epithelium. We report an unusual case of central mucoepidermoid carcinoma in an 18-year-old Japanese man with an odontogenic cyst.

Protumor role of estrogen receptor expression in oral squamous cell carcinoma cells

OBJECTIVE

Accumulating evidence has demonstrated the protumor role of estrogen receptor (ER)-mediated signaling in multiple cancer types, which is distinct from this signaling in sex steroid-dependent organs. However, its role in oral squamous cell carcinoma (OSCC) remains unclear.

STUDY DESIGN

We assessed the expression of ERα and ERβ in human OSCC tissues by immunohistochemistry and evaluated the expression of both receptors in OSCC cell lines by immunoblotting and flow cytometry. To further assess the contribution of ER-mediated signals to oral cancer progression, proliferation, invasion, and chemosensitivity, cell lines were stimulated with the ER agonist β-estradiol.

RESULTS

Immunohistochemical analysis of OSCC tissues showed that ERβ was present in the cytoplasm and nuclei of OSCC cells. In contrast, ERα was not detected in any of the cases analyzed. Additionally, the proliferation and invasiveness of OSCC cells were significantly elevated following stimulation with β-estradiol. Chemotherapeutic agent-induced apoptosis of cancer cells was attenuated by pretreatment with β-estradiol.

CONCLUSIONS

ER-mediated signaling plays a crucial role in oral cancer progression by facilitating the proliferation, invasion, and chemoresistance of OSCC cells, indicating its potential for developing novel targeted therapies for this type of cancer.

Durable complete response to immunotherapy with anti-PD-1 antibody nivolumab in a patient with oral squamous cell carcinoma presenting with lung metastasis: A case report

Although the optimal treatment method for metastatic oral cancer remains largely unknown, the present case suggests that immunotherapy is a potentially promising alternative for metastatic oral cancer in which other therapies are no longer effective.

Orthotopic tongue squamous cell carcinoma (SCC) model exhibiting a different tumor-infiltrating T-cell status with margin-restricted CD8+ T cells and regulatory T cell-dominance, compared to skin SCC

The immunological, and especially T cell, status of the tumor microenvironment affects tumor development and the efficacy of cancer treatment. To devise suitable combination therapies based on the results of murine tumor models, a more realistic orthotopic model is required. In this study, we generated a murine model of tongue squamous cell carcinoma (SCC), in which the tumor-immune cell interactions were recapitulated, and examined tumor- and T-cell status compared to a skin-transplanted SCC model by multiplex immunofluorescence staining for epidermal growth factor receptor, CD31, CD8, CD4, and Foxp3. Administration of SCCVII cells did not induce undesirable tissue damage or inflammation. In tongue SCC, abundant T-cell infiltration was observed at the tumor margin, but not in the core. Tongue SCC predominantly showed CD8⁺ T or Foxp3⁺ regulatory T cell (Treg)-infiltration. In contrast, skin-transplanted SCC showed abundant infiltration of T cells in the whole tumor area, which was dominated by Tregs. An orthotopic tongue SCC model showed differences in tumor and T-cell status compared to the skin-transplanted SCC model. Our tongue SCC model may enhance understanding of tumor-host interactions and enable evaluation of therapeutic efficacy.

Alterations in composition of immune cells and impairment of anti-tumor immune response in aged oral cancer-bearing mice

OBJECTIVES

Aging has been suggested to be associated with immune dysregulation. An understanding of alterations in the host immunity with advancing age is, therefore, important for designing immune therapy for elderly cancer patients. In this context, not much is known about age-associated alterations in the immune system in oral cancer.

METHODS

To evaluate age-associated alterations in the immune system, which might affect anti-tumor immune responses in oral cancer, we performed a comparative analysis of the proportion of different immune cells, the proliferative capacity of T cell compartment, and the response against immune therapies targeting immune check point molecules between young and aged oral cancer-bearing mice.

RESULTS

The proportion of immune regulatory cells, such as regulatory T cells and myeloid derived suppressor cells, was significantly increased in aged mice compared to that in young mice. Moreover, the expression of PD-1 and CTLA-4 on both CD4⁺ and CD8⁺ T cells was elevated in aged mice compared to that in young mice, and the proliferative abilities of CD4⁺ and CD8⁺ T cells derived from aged mice were significantly reduced following stimulation of T-cell receptors. Moreover, tumor growth was significantly enhanced in aged mice compared to that in young mice. However, immunotherapies targeting PD-1, CTLA-4, and PD-L1 resulted in faster tumor regression in aged mice than in young mice.

CONCLUSIONS

Together, our results indicate that age-associated alterations in the immune system are directly associated with the impairment of anti-tumor immunity in aged mice bearing oral cancer, and might facilitate the progression of the tumor.

Enhanced expression of PD-L1 in oral squamous cell carcinoma-derived CD11b(+)Gr-1(+) cells and its contribution to immunosuppressive activity

Cancer is often associated with dysregulation of both the humoral and cellular immune response, which in some instances is believed to result from changes in immune cell populations. For example, immunosuppressive CD11b(+)Gr-1(+) myeloid-derived suppressor cells have been shown to proliferate in the tumor microenvironment and surrounding tissues, highlighting the relationship between tumor growth and impairment of the immune response. However, the role of myeloid-derived suppressor cells in cancer progression has not been fully characterized because these cells are heterogeneous with properties influenced by the type and location of the tumor. Here, we show that CD11b(+)Gr-1(+) cells are elevated in the peripheral blood, spleen, and tumor of mice with oral squamous cell carcinoma. The phenotype and function of these cells varied depending on the tissue of origin. In particular, CD11b(+)Gr-1(+) cells in tumors expressed PD-L1 more abundantly than those in other tissues. Accordingly, CD11b(+)Gr-1(+) cells from tumors, but not from the spleen, suppressed T cell proliferation in vitro. The results suggest that tumor-derived or immune factors result in the accumulation of phenotypically and functionally diverse populations of CD11b(+)Gr-1(+) cells in mice with oral squamous cell carcinoma. The data also indicate that PD-L1 expression in CD11b(+)Gr-1(+) cells contributes to immune suppression, implying that targeting both myeloid-derived suppressor cells and PD-L1 would be an effective immunotherapeutic strategy against oral cancer.

Systemic administration of a TLR7 agonist attenuates regulatory T cells by dendritic cell modification and overcomes resistance to PD-L1 blockade therapy

Research on immune checkpoint blockade therapy has made great progress in cancer immunotherapy, but the number of patients who benefit from this therapy remains limited. In this study, we examined the effects of monotherapy with systemic low-dose resiquimod, a synthesized TLR7 agonist, and examined its combined effects with PD-L1 blockade in two PD-L1 blockade-resistant tumor models (SCCVII and Colon 26). Resiquimod monotherapy in SCCVII tumors, representing impaired CD8⁺ T cell function and accelerated regulatory T cells (Tregs) within the tumors, efficiently reduced tumor growth with more recruitment of CD8⁺ T cells and a reduction of Treg. The results of resiquimod monotherapy in Colon 26, representing impaired Treg recruitment, were inferior to that in SCCVII. Combined resiquimod treatment with PD-L1 blockade exerted clear additional effects, as it was associated with reduced tumor size, attenuation of Tregs, and an increased ratio of CD8⁺ T cells/Tregs in both tumors. Systemic administration of low-dose resiquimod induced a transient and rapid activation of plasmacytoid and conventional dendritic cells, resulting in enhanced priming of T cells in regional lymph nodes. Experiments with more limited doses of resiquimod that did not yield beneficial effects after single treatment, showed additional effects to PD-L1 blockade and comparable antitumor effects when the frequency of anti-PD-L1 therapy was decreased. Our results suggest that systemic administration of low-dose resiquimod is useful as a companion drug to PD-1/PD-L1 blockade therapy.

Conventional osteosarcoma of the mandible successfully treated with radical surgery and adjuvant chemotherapy after responding poorly to neoadjuvant chemotherapy: a case report

Background

Osteosarcoma, the most common primary bone malignancy, has an extremely poor prognosis and a high rate of local recurrence and distal metastases. Because osteosarcomas of the head and neck region are rare, accounting for less than 10% of all osteosarcoma cases, limited information is available about their treatment and prognosis. Because of the high rate of distal metastases associated with extragnathic osteosarcoma, surgery combined with chemotherapy is currently considered essential in its treatment. However, the role of chemotherapy has not been well elucidated in the treatment of head and neck osteosarcoma because of the rarity of this condition.

Case presentation

In this report, we present the case of a 58-year-old Japanese woman with osteosarcoma of the mandible that was treated with radical surgery combined with neoadjuvant and adjuvant chemotherapy. Because the tumor showed rapid growth during neoadjuvant chemotherapy, neoadjuvant chemotherapy was suspended and surgical resection was performed, followed by adjuvant chemotherapy. No evidence of local recurrence and distal metastasis was found 14 months after initial treatment. Local control is considered a principal prognostic factor for head and neck osteosarcoma.

Conclusions

Wide surgical excision should be considered a primary goal even during neoadjuvant chemotherapy, especially in cases that respond poorly to neoadjuvant chemotherapy.

Combined preoperative measurement of three inferior alveolar canal factors using computed tomography predicts the risk of inferior alveolar nerve injury during lower third molar extraction

A retrospective cohort study was performed to assess the clinical usefulness of combination assessment using computed tomography (CT) images in patients undergoing third molar extraction. This study included 85 patients (124 extraction sites). The relationship between cortication status, buccolingual position, and shape of the inferior alveolar canal (IAC) on CT images and the incidence of inferior alveolar nerve (IAN) injury after third molar extraction was evaluated. IAN injury was observed at eight of the 124 sites (6.5%), and in five of 19 sites (26.3%) in which cortication was absent+the IAC had a lingual position+the IAC had a dumbbell shape. Significant relationships were found between IAN injury and the three IAC factors (cortication status, IAC position, and IAC shape; P=0.0001). In patients with the three IAC factors, logistic regression analysis indicated a strong association between these factors and IAN injury (P=0.007). An absence of cortication, a lingually positioned IAC, and a dumbbell-shaped IAC are considered to indicate a high risk of IAN injury according to the logistic regression analysis (P=0.007). These results suggest that a combined assessment of these three IAC factors could be useful for the improved prediction of IAN injury.