Local Low-dose Anti-PD-L1 Antibodies Improve Antitumor Effects in Oral Squamous Cell Carcinoma.

BACKGROUND/AIM: Immune checkpoint inhibitors are highly effective for treating recurrent and metastatic head and neck cancers. However, they require systemic administration and are associated with immune-related adverse events (irAEs). Reducing therapeutic antibody doses to prevent irAEs is challenging. MATERIALS AND METHODS: Mouse buccal mucosa squamous cell carcinoma cells (Sq-1979) were transplanted into the backs of mice to induce tumors. The antitumor efficacy and tumor immunohistological environment in tumor-bearing mice were compared after administering a standard dose of programmed death-ligand 1 (PD-L1) antibodies systemically (200 mg/body) or 1/10th of the standard dose (20 mg/body) directly to tumors. Mice received four doses of antibody administered in 3-day intervals. Tumor reduction rates and antitumor efficacies were evaluated 21 days after initiating treatment. CD8+T cell counts and PD-L1, PD-1, perforin, and granzyme B levels; CD25 and Foxp3 expression levels; and tumor Tregs were assessed in the resected subcutaneous tumors. RESULTS: The antitumor efficacies in the local low-dose and systemic standard-dose groups were compared with that of the control group. The efficacies of the two treatment groups were similar, and both treatment groups revealed significant antitumor effects compared to the control group. Perforin and granzyme B levels were higher in the local low-dose group (p<0.05). CONCLUSION: Local low-dose administration of anti-PD-L1 antibodies exhibits antitumor efficacy similar to systemic standard-dose administration suggesting that local low-dose administration is useful for treating oral squamous cell carcinoma.

The ECAS system can superselectively administer anticancer drugs to numerous feeding arteries from the superficial temporal artery: A case report and literature review.

Superselective intra-arterial chemoradiotherapy (SSIACRT) is one of the curative treatments for advanced oral cancer. SSIACRT can reportedly treat cervical lymph node metastases in the level I-IIA area by super selectively catheterizing the facial artery (FA) and infusing drugs. However, since advanced oral cancer lesions involve a number of feeding vessels, retrograde treatment requires the placement of catheters from the superficial temporal artery (STA) and occipital artery (OA). Furthermore, in the case of level IIB lymph node metastasis, the catheter must be changed because it is necessary to administer anticancer drugs to more than three routes, including the OA, when the feeding arteries of the primary tumor are combined. The external carotid artery sheath (ECAS) system used in the present study involves the insertion of a microcatheter or steering catheter from one route of the STA, allowing selection of numerous feeding vessels, including the OA. The ECAS system can facilitate the administration of chemotherapy via the STA simultaneously to the maxillary artery, lingual artery, FA and OA. The present study describes cases of maxillary gingival cancer and tongue cancer with cervical lymph node metastasis, which were treated with the ECAS system via the STA; the treatment successfully controlled both the primary tumor and cervical lymph node metastasis. In the two cases described in the present study, metastatic lymph nodes were found in the level ⅠB and ⅡB region, but were successfully treated by administering cisplatin via the OA, in addition to the primary lesion. To date, to the best of our knowledge, there is no case report clearly referring to the treatment of lymph node metastasis using the ECAS system. In conclusion, SSIACRT using ECAS may be considered a useful treatment for oral cancer with cervical lymph node metastasis.

An In Vivo Study of Local Administration of Low-dose Anti-PD-1 Antibody Using an Oral Cancer Cell Line.

BACKGROUND/AIM: The immunotherapy approach using anti-programmed cell death 1 (PD-1) antibody has been demonstrated in oral cancer treatment. However, serious immune-related adverse events (irAE) have been reported. If local administration of small doses of anti-PD-1 antibody via intraarterial chemoradiotherapy could have the same antitumor effect of systemic administration, this can reduce irAE and medical expenses. In this study, we investigate the antitumor effects of local and systemic administration of a small amount of anti-PD-1 antibody, the overall survival (OS), and the immune environment around cancer. MATERIALS AND METHODS: A mouse buccal mucosal oral squamous cell carcinoma cell line (Sq-1979) was used, and anti-mouse PD-1 was used as the drug. The cell line was transplanted to mouse, and the drug was locally (30 mg/body) and systemically (300 mg/body) administered in a dose. The tumor shrinkage rate and antitumor effect were examined 21 and 29 days after the start of administration. The OS was also compared in each of the groups. Furthermore, the subcutaneous growth of the tumors was inhibited, and the expressions of PD-L1, CD8T cells, perforin, and granzyme B were examined. RESULTS: We found that the local low-dose and systemic groups had the same antitumor effect, OS also showed a significant prolongation. In addition, indicated that the expression of granzyme B was higher in the local low-dose group. CONCLUSION: Local low-dose administration of anti-PD-1 antibody showed the same antitumor effect and OS as systemic normal-dose administration. Therefore, local low-dose administration in oral cancer can be useful.

Study of the Acquisition of Sensitivity to Paclitaxel Plus Cetuximab by the Addition of Low-dose Proteasome Inhibitor.

BACKGROUND/AIM: Although paclitaxel plus cetuximab for recurrent/metastatic oral squamous cell carcinoma (OSCC) has a relatively high success rate, many cases are refractory. We investigated the change in nuclear factor-kappa B (NF-B) expression after this combination therapy using microcollagen 3D cell culture. We also investigated changes in antitumor efficacy using low doses of paclitaxel-cetuximab combined with the proteasome inhibitor bortezomib on a cell line with low sensitivity to paclitaxel plus cetuximab. MATERIALS AND METHODS: Eight human OSCC cell lines were cultured in 3D and exposed to paclitaxel-cetuximab. real-time polymerase chain reaction was used to evaluate NF-B mRNA expression in OSCC cell lines in vivo and in vitro after exposure to anticancer agents. Activity at the protein level was confirmed using western blotting. Bortezomib (0.002-0.4 µg/ml) was added to paclitaxel-cetuximab and its effects assessed in OSCC cell lines with low paclitaxel-cetuximab sensitivity. RESULTS: mRNA and protein expression of NF-B was significantly reduced after treatment with paclitaxel-cetuximab in cell lines sensitive to this combination. In contrast, both mRNA and protein expression significantly increased in the cell lines with low sensitivity to paclitaxel plus cetuximab. The addition of low concentrations of bortezomib to cell lines with low sensitivity to paclitaxel-cetuximab was found to enhance antitumor efficacy. CONCLUSION: Increased NF-B expression strongly contributes to resistance to paclitaxel-cetuximab, suggesting that the administration of small doses of bortezomib, which inhibits NF-B, combined with paclitaxel-cetuximab may enhance antitumor efficacy against cancer cells with low sensitivity to the combination therapy.

PTEN Is Activated by the Addition of Cetuximab to Paclitaxel in Oral Squamous Cell Carcinoma.

BACKGROUND/AIM: The mechanisms through which cetuximab (cMab) coadministration with paclitaxel (PTX) enhances antitumor efficacy remain unclear. We examined the mechanism of the antitumor enhancing effect of cMab by determining changes in gene expression in the PI3K-AKT pathway. MATERIALS AND METHODS: Eight human oral squamous cell carcinoma (OSCC) cell lines were cultured three-dimensionally and exposed to PTX + cMab. The expression levels of PTEN mRNA in OSCC cell lines after anticancer drug treatment were assessed using real-time PCR. PTEN mRNA expression levels were also confirmed after administration of PTX + cMab in vivo. Western blot analysis was used to confirm the results at the protein level. RESULTS: PTEN mRNA and protein expression were significantly increased only in the cell lines with high sensitivity to PTX + cMab, and similar results were observed in vivo. CONCLUSION: PTEN activation may enhance the antitumor effect of PTX + cMab.

Optimal Contact Concentration of Paclitaxel in the Collagen Gel Droplet-Embedded Culture Drug Sensitivity Test for Human Oral Squamous Cell Carcinoma and Evaluation of Combination with Cetuximab.

OBJECTIVE: A combination of the taxane anticancer drug paclitaxel (PTX) and molecular target drug cetuximab (cMab) is effective for the treatment of head and neck squamous cell carcinoma (HNSCC). However, its use is associated with serious side effects, such as neuropathy and myelosuppression. In addition, it is administered regardless of patient sensitivity because biomarkers indicating its efficacy are unavailable. Therefore, we investigated the usefulness of setting the indicated contact concentration of PTX and predicted the antitumor effect of combined contact with cMab using the collagen gel droplet-embedded culture drug sensitivity test (CD-DST). METHOD: Twelve human oral squamous cell carcinoma (OSCC) cell lines (i.e., SAS, HSC-2, HSC-3, HSC-4, OSC-19, OSC-20, KON, HO-1-N-1, HO-1-u-1, SAT, SCC-4, and Nialym) were used. Using the CD-DST, we calculated the optimal contact concentration of the cells with PTX based on the clinical response rate of HNSCC and evaluated the combined contact with cMab. Furthermore, nude mice were treated with standalone PTX and PTX + cMab, and the results were compared with those of the CD-DST. RESULTS: Based on the CD-DST, 0.1 µg/mL was the optimal contact concentration of PTX, to which the cells showed dose-dependent sensitivity. Moreover, the CD-DST method was used to evaluate the antitumor effects on OSCC even when PTX was used in combination with cMab. The antitumor effects in the CD-DST and nude mice were correlated (p < 0.05). CONCLUSION: The CD-DST results suggested that it was possible to predict the clinical effects of single-contact PTX and the enhancing effect of cMab + PTX.

Identification of the optimal cetuximab concentration that is effective against oral squamous cell carcinoma in collagen gel droplet embedded culture drug sensitivity testing.

Anticancer drug sensitivity testing using the collagen gel droplet embedded culture drug sensitivity test (CD-DST) on oral squamous cell carcinoma (OSCC) samples beginning from 2010 has been conducted. The present study investigated the effect of adding cetuximab (Erbitux®), a molecularly targeted drug, on anticancer drug activity against clinical OSCC specimens. A total of 25 specimens were obtained from 25 patients with OSCC between October 2013 and December 2017. The present study conducted anticancer drug sensitivity testing for cisplatin (CDDP), 5-fluorouracil (5-FU), cetuximab, three-drug combination, single agent and multi drug combinations, and cetuximab addition to the aforementioned regimens using CD-DST. In addition, the optimum concentration of each drug was evaluated. The overall evaluation success rate of the CD-DST method for OSCC specimens was 84.0% (21 of 25 cases); sensitivity to anticancer drugs and cetuximab could be evaluated. The in vitro efficacy rate of a cetuximab single agent and CDDP + 5-FU (PF) at a cut-off value of 50% was similar to the known clinical response rate. However, at a cut-off value of 50%, the in vitro efficacy of PF + cetuximab was calculated to be 40%, which was higher than the clinical response rate. The CD-DST method could be used to evaluate cetuximab, a molecularly targeted drug. Furthermore, its additive effect on conventional chemotherapy could be evaluated. The CD-DST method is suitable for evaluating and selecting chemotherapy regimens, including molecularly targeted drugs. Future studies are required to generate and evaluate relevant clinical data.

Retrograde superselective intra-arterial chemoradiotherapy combined with hyperthermia and cetuximab for carcinoma of the buccal mucosa with N3 lymph node metastasis: a case report.

We herein report a case of squamous cell carcinoma of the buccal mucosa with N3 cervical lymph node metastasis in a 63-year-old man. The patient was treated with combination therapy comprising radiotherapy (2 Gy/day, total of 70 Gy), superselective intra-arterial chemotherapy via a superficial temporal artery (docetaxel, total of 70 mg/m2 and cisplatin, total of 175 mg/m2), cetuximab (initial dose of 400 mg/m2 with subsequent weekly doses of 250 mg/m2 intravenously), and four sessions of hyperthermia for cervical lymph node metastases. The patient responded well to the therapy, with a complete response of the primary tumor. Radical neck dissection was performed with reconstructive surgery, including resection of the overlying skin. A pathologic complete response was achieved for the N3 and all other cervical lymph node metastases. The patient showed no evidence of recurrence in the 3 years following treatment. Based on the findings in the present case, the use of retrograde superselective intra-arterial chemoradiotherapy combined with hyperthermia and cetuximab seems to be a promising modality for patients with N3 cervical lymph node metastasis of oral cancer.

Clinical study on collagen gel droplet-embedded culture drug sensitivity test for multidrug combination chemotherapy and super selective intra-arterial infusion chemoradiotherapy in oral squamous cell carcinoma.

Using trace three-dimensional culture, the collagen gel droplet-embedded culture drug sensitivity test (CD-DST) can be tested even in cases with a small number of cells, including oral squamous cell carcinoma (OSCC), and evaluation of the antitumor effect with a drug concentration close to the in vivo level is possible. The present report aimed to evaluate the utility of the CD-DST in the assessment of the in vitro efficacy of single-agent and multidrug combination chemotherapy for OSCC in comparison with the clinical response rates and to examine the possible clinical application of CD-DST for such cases. A total of 33 OSCC patients from whom 33 samples were obtained from January 2010 to September 2015 were included. CD-DST was performed, individually and in combination, on the three drugs [i.e., cisplatin (CDDP), 5-fluorouracil (5-FU), and docetaxel (DOC)] and on super selective intra-arterial infusion chemoradiotherapy (IACRT). The overall evaluable rate of the CD-DST in OSCC was 81.8% (27 of 33 cases) and the sensitivity to each anticancer drug was evaluated. The in vitro efficacy rates of IACRT, cisplatin + 5-fluorouracil, and docetaxel + cisplatin + 5-fluorouracil (TPF) confirmed the estimated clinical response rates. In 14 of 33 patients, the results of CD-DST were compared with clinical efficacy, which was judged based on measurable lesions on imaging. For TPF therapy, the sensitivity test of the IACRT had a positive predictive value of 90.9% (10 of 11 cases) and a negative predictive value of 100% (3 of 3 cases); the accuracy of the susceptibility test for the anticancer agents was 92.8% (13 of 14 cases). The CD-DST may be useful in selecting multidrug combination chemotherapy and IACRT for OSCC, however, accumulation of further clinical data is required in the future.

Collagen gel droplet-embedded culture drug sensitivity testing in hard palate cancer-predicted antitumor efficacy of cetuximab: A case report.

In vitro anticancer drug sensitivity assessments have been performed for various types of cancer, and an association with clinical response has been observed. The collagen gel droplet-embedded culture drug sensitivity test (CD-DST) is an in vitro anticancer drug sensitivity test that has recently reported to be useful in oral squamous cell carcinoma (OSCC). CD-DST allows for the analysis of a smaller number of cells compared with other anticancer drug sensitivity tests. The present study reported a successful analysis of anticancer drug sensitivity using CD-DST on cervical lymph node tissue dissected following neoadjuvant chemotherapy from a 55-year-old man with advanced hard palate cancer. Tumor resection and bilateral neck dissection were performed following neoadjuvant chemotherapy (docetaxel + cisplatin + 5-fluorouracil; TPF) for hard palate cancer T2N2cM0. Local recurrence and cervical multiple skin metastasis occurred ~8 months after surgery, and the patient received six doses of cetuximab (C-mab) + cisplatin + 5-fluorouracil (C-mab + PF) administration, which is a type of molecular-targeted therapy. Following the use of the CD-DST method, the clinical response was noted as stable disease following execution of TPF and partial response following execution of C-mab + PF. In addition, low sensitivity by TPF and high sensitivity by C-mab + PF were reported. The CD-DST method reflected the clinical response for the patient, and the results of the current study indicate that CD-DST is a useful tool for selecting chemotherapeutic drugs for patients with OSCC.

Clinical outcomes of retrograde intra-arterial chemotherapy concurrent with radiotherapy for elderly oral squamous cell carcinoma patients aged over 80 years old.

BACKGROUND: The aim of this retrospective observational study was to evaluate toxicities, overall survival, and locoregional control in elderly oral squamous cell carcinoma patients who had undergone retrograde intra-arterial chemotherapy combined with radiotherapy. METHODS: Thirty-one elderly patients over 80 years old with oral squamous cell carcinoma were enrolled in present study. The treatment schedule consisted of intra- arterial chemotherapy (docetaxel, total 60 mg/m2; cisplatin, total 150 mg/m2) and daily concurrent radiotherapy (total, 60 Gy) for 6 weeks. RESULTS: The median patient age was 82.5 years old (range, 80-88 years). Of the 31 patients, six (19%) had stage II, 6 (19%) had stage III, 17 (55%) had stage IVA, and 2 (6%) had stage IVB. The median follow-up period for all patients was 37 months (range, 7-86 months). The 3-year overall survival and locoregional control rates were 78% and 81%, respectively. The major acute grade 3 adverse events were oral mucositis in 22 (71%) patients, neutropenia in 16 (52%), and dermatitis in 11 (35%). With respect to late toxicities, 1 patient (3%) developed grade 3 osteoradionecrosis of the jaw. No grade 4 or higher toxicities were observed during the treatment and follow-up periods. CONCLUSIONS: Retrograde intra-arterial chemotherapy combined with radiotherapy was effective in improving overall survival and locoregional control even for elderly patients.

Collagen gel droplet-embedded culture drug sensitivity testing in squamous cell carcinoma cell lines derived from human oral cancers: Optimal contact concentrations of cisplatin and fluorouracil.

The collagen gel droplet-embedded culture drug sensitivity test (CD-DST) is an anticancer drug sensitivity test that uses a method of three-dimensional culture of extremely small samples, and it is suited to primary cultures of human cancer cells. It is a useful method for oral squamous cell carcinoma (OSCC), in which the cancer tissues available for testing are limited. However, since the optimal contact concentrations of anticancer drugs have yet to be established in OSCC, CD-DST for detecting drug sensitivities of OSCC is currently performed by applying the optimal contact concentrations for stomach cancer. In the present study, squamous carcinoma cell lines from human oral cancer were used to investigate the optimal contact concentrations of cisplatin (CDDP) and fluorouracil (5-FU) during CD-DST for OSCC. CD-DST was performed in 7 squamous cell carcinoma cell lines derived from human oral cancers (Ca9-22, HSC-3, HSC-4, HO-1-N-1, KON, OSC-19 and SAS) using CDDP (0.15, 0.3, 1.25, 2.5, 5.0 and 10.0 µg/ml) and 5-FU (0.4, 0.9, 1.8, 3.8, 7.5, 15.0 and 30.0 µg/ml), and the optimal contact concentrations were calculated from the clinical response rate of OSCC to single-drug treatment and the in vitro efficacy rate curve. The optimal concentrations were 0.5 µg/ml for CDDP and 0.7 µg/ml for 5-FU. The antitumor efficacy of CDDP at this optimal contact concentration in CD-DST was compared to the antitumor efficacy in the nude mouse method. The T/C values, which were calculated as the ratio of the colony volume of the treatment group and the colony volume of the control group, at the optimal contact concentration of CDDP and of the nude mouse method were almost in agreement (P<0.05) and predicted clinical efficacy, indicating that the calculated optimal contact concentration is valid. Therefore, chemotherapy for OSCC based on anticancer drug sensitivity tests offers patients a greater freedom of choice and is likely to assume a greater importance in the selection of treatment from the perspectives of function preservation and quality of life, as well as representing a treatment option for unresectable, intractable or recurrent cases.