Intracellular Nampt impairs esophageal squamous cell carcinoma neo-adjuvant chemotherapy response independent of eNampt

Abstract

Nampt consists of iNampt and eNampt, might contribute to modulating obesity-related malignancies and impairing response to chemotherapy in a range of cancers. This study explored the role of Nampt and adiposity in the progression and response to neo-adjuvant chemotherapy of esophageal squamous cell carcinoma (ESCC). Patients with ESCC were treated with 2 cycles of neo-adjuvant chemotherapy, then evaluated for surgery. Tumor regression grading (TRG) and prognosis of these patients were collected. Anthropometry was well utilized. Serum eNampt was determined by enzyme-linked immunosorbent assay, iNampt expression in tissues were assessed by PCR, western blot and immunohistochemistry. eNampt in sera elevated significantly in these over-weight or obese patients, and was positively associated with body mass index (BMI), waist circumference, visceral fat area (VFA), subcutaneous fat area (SFA) and total fat area (TFA) (P<0.05). iNampt expression in the mRNA and protein levels were up-regulated in ESCC compared to their adjacent non-tumor specimens (P<0.05). iNampt protein staining revealed mainly in the cytoplasm and nuclei, while it was not related to serum eNampt, BMI, waist circumference, VFA, SFA and TFA (P>0.05). Pre-treatment iNampt, BMI, SFA, TFA and age significantly correlated with neo-adjuvant chemotherapy response, and iNampt expression and age were independent predictors (P<0.05). Pre-treatment iNampt, ypT, ypN, ypTNM stage and TRG were associated with the survival of ESCCs, and ypN stage and TRG were independent prognostic factors (P<0.05). In conclusion, iNampt impaired ESCC response to neo-adjuvant chemotherapy independent of eNampt, targeting iNampt to increase ESCC response to neo-adjuvant chemotherapy would improve the prognosis of ESCCs.

Keywords: Esophageal squamous cell carcinoma; chemotherapy response; nampt; neo-adjuvant chemotherapy; obesity; tumor regression grading.

Figure 1

Response to chemotherapy of ESCC assessed in the pathology by CAP-TRG following 2 cycles of neo-adjuvant chemotherapy, and H&E stained sections were demonstrated at ×400 magnification. (A) TRS = 0, (B) TRS = 1, (C) TRS = 2, and (D) TRS = 3.

Figure 2

Response to neo-adjuvant chemotherapy of ESCC evaluated in the image by RECIST 1.1 following 2 cycles of chemotherapy. (A) CR, (B) PR, and (C) SD.

Figure 3

Percentage change of tumor in the image of all the target patients after 2 cycles of neo-adjuvant chemotherapy. Taking as reference the baseline sum diameters, CR (n = 2), all target lesions disappeared; PR (n = 35), at least a 30% decrease in the sum of diameters of target lesions; PD (n = 1), at least a 20% increase; SD (n = 22), neither reached PR nor attained PD.

Figure 4

iNampt expression in ESCC and their adjacent non-tumor tissues (n = 5) was shown, mRNA expression was measured by means of qRT-PCR using β-actin as internal control (A), protein expression was determined by Western blot (B and C). Compared to these adjacent non-tumor, ESCC had elevated iNampt expression in the mRNA level (1.9 ± 0.3 versus 1.0 ± 0.2) and protein level (5.73 ± 1.03% versus 2.12 ± 0.67%). *; P<0.05.

Figure 5

iNampt protein expression in these tumors from endoscopic biopsy was evaluated, and the sections were demonstrated at ×400 magnification. (A) positive staining and (B) negative staining.

Figure 6

Kaplan-Meier analysis of disease-specific survival of ESCCs with 2 cycles of neo-adjuvant chemotherapy following surgery relative to iNampt expression.