A Nanotherapeutic Strategy to Reverse NK Cell Exhaustion

As a specialized immune effector cell, natural killer (NK) cells play a very important role in immunotherapy, but tumor immunosuppression caused by abnormal expression of cancer cells seriously weakens its therapeutic effect and leads to exhaustion. Here, self-assembled selenium-containing nanoparticles (NPs) composed of cetuximab, C5SeSeC5, and inhibitor LY345899 are developed to reverse NK cell exhaustion. The obtained NPs can target epidermal growth factor receptor on the surface of cancer cells and locate it in mitochondria. The released LY345899 can inhibit the activity of methylene tetrahydrofolate dehydrogenase 2 and produce excessive reactive oxygen species, leading to the formation of seleninic acid, further reducing the expression of human leukocyte antigen E , which is responsible for the NKG2A-related NK cell inhibition. As a result, the enhanced NK-cell-mediated immunotherapy in conjunction with the cetuximab-mediated antibody-dependent cell-mediated cytotoxicity effect can not only effectively inhibit the growth of xenograft tumors, but also significantly suppress the growth of untreated distant tumors via the abscopal effect. This work, the combination of seleninic acid, LY345899, and cetuximab, provides a new strategy for reversing NK cell exhaustion and has great potential for use in the treatment of metastatic tumors.

Cetuximab and panitumumab in KRAS wild-type colorectal cancer: a meta-analysis

BACKGROUND

Anti-epidermal growth factor receptor monoclonal antibodies (panitumumab [P] and cetuximab [C]) are approved and effective only in KRAS wild-type patients with advanced colorectal cancer. The purpose of our meta-analysis is to evaluate the real effects of C and P in KRAS wild-type patients treated in randomized trials.

PATIENTS AND METHODS

Eligible studies included prospective, randomized, and controlled trials in which either C or P had been added to standard antineoplastic therapy or best supportive care and data for KRAS wild-type patients only had been calculated. Six thousand three hundred ninety-five patients' tumor samples have been analyzed (total wild-type n = 3,254; experimental arm n = 1,608; control arm n = 1,646). Relative risks (RRs) with 95% confidence intervals (CIs) for response rate were calculated, as well as hazard ratios (HRs)for progression-free survival (PFS) and overall survival.

RESULTS

The overall RR of response rate is 1.69 (p = 0.003) in all trials. The overall HRs for PFS and survival are 0.65 (p = 0.0006) and 0.84 (p = 0.03), respectively, and both are significant. The HRs for PFS and survival in C trials are 0.64 and 0.79, respectively, and 0.65 and 0.87, respectively, in P trials, although only the results achieved in P trials are significant (p = 0.0007 and p = 0.03). Both response rate (RR = 10.94) and PFS (HR = 0.51) have increased more in pretreated patients than in first-line trials.

CONCLUSION

The addition of anti-EGFR monoclonal antibodies to standard anticancer therapy in KRAS wild-type colorectal cancer showed an overall significantly increased risk of objective response rate and increased progression-free and overall survival. Only the results achieved in P randomized trials are significant, and the strongest results have been achieved in pretreated patients.