Rapid and quantitative method for evaluating the personal therapeutic potential of cancer drugs

Abstract

An in vitro, rapid, and quantitative cell-based assay is needed to predict the efficacy of cancer drugs in individual patients, because a cancer patient may have unconventional aspects of tumor development. Here we report a rapid and label-free quantitative method for verifying apoptosis in living cancer cells cultured on a sensor chip with a newly developed high-precision surface plasmon resonance (SPR) sensor. The time-course cell reaction was monitored as the SPR angle change rate for 5 min during a 35-min cell culture of pancreatic cancer lines with a drug. The time-course cell reaction was significantly related to cell viability counted after 48 h as assessed by caspase-3 activity assay of apoptosis. Furthermore, the detected SPR signal was derived from the decrease in inner mitochondrial membrane potential. The results obtained are universally valid for various cancer drugs mediating apoptosis through different cell-signaling pathways and even for combined use in various pancreatic cancer cell lines. This system can be applied in a clinical setting to evaluate the personal therapeutic potential of drugs including pharmacodynamic interactions.

Development of Signaling Echo Method for Cell-based Quantitative Efficacy Evaluation of Anti-cancer Drugs in Apoptosis without Drug Presence Using High-precision Surface Plasmon Resonance Sensing

“…drug efficacy prediction using a standard method is difficult because the positive differential SPR angle rate of change obtained using the standard method is negatively related to cell viability, as described in a previous work. 8 Additionally, a cyclical interaction will exist between the cell membrane and roscovitine because some small waves are recognized from a trend of the SPR angle change. This fact implies that the continuous cell membrane change caused by roscovitine crossing the cell membrane disturbs the monitoring of ΔΨm.…”

“…Furthermore, an incubation time of at least 30 min is necessary for effective penetration of the drug via the cell membrane into the cytosol, as demonstrated previously in mitochondria depolarization experiments related to monitoring the effect of carbonyl cyanide 3-chlorophenylhydrazone administration. 8 Based on those results, to minimize the interaction between the cell membrane and an anti-cancer drug, we nominated the pre-incubation of cancer cells with a drug and removal of the anti-cancer drug before SPR measurements. However, the cell retained the apoptosis signal in the cell (signaling echo method).…”

“…31 The ΔΨm of all mitochondria in a cell was observed by SPR: simultaneous fluorescence observation by an epi-illumination using JC-1 iodide equaled the results obtained using SPR in our previous study. 8 In a cell, several hundred mitochondria exist with heterogeneity in ΔΨm. 32 We measured about 1000 cells using SPR.…”

“…7 In an earlier study, we demonstrated a rapid and label-free quantitative evaluation method and instrument for apoptosis efficacy of anti-cancer drugs through a reaction analysis of living pancreatic cancer cells cultured on a sensor chip: a newly developed high-precision (50 ndeg s -1 average fluctuation) surface plasmon resonance (SPR) sensor. 8 At 35 min after the addition of an anti-cancer drug to the cell, the cell reaction was monitored for 5 min using differential SPR angle rates of change. It was related closely to cell viability.…”

“…Furthermore, the differential SPR angle change reflects both changes in the cell membrane potential until around 30 min cell culture with a subsequent anti-cancer drug and in ΔΨm change. 8 These changes require a sampling time decision of the differential SPR angle change to evaluate the anti-cancer drug efficacy.…”