[Sensitivity of colorectal cancer organoids to hyperthermic intraperitoneal chemotherapy with lobaplatin].

Objective: To investigate the sensitivity of tumor organoids derived from samples of colorectal cancer to lobaplatin and oxaliplatin hyperthermic perfusion in vitro and to assist clinical development of hyperthermic intraperitoneal chemotherapy. Method: Tumor samples and relevant clinical data were collected from patients with pathologically confirmed colorectal cancer in the Sixth Affiliated Hospital of Sun Yat-sen University from July 2021 to December 2022. Organoids were cultured and tumor tissue were passaged. In vitro hyperthermic perfusion experiments were performed on organoids with good viability. Firstly, 10 organoids were treated with oxaliplatin and lobaplatin at the following six concentrations: 1 000, 250, 62.5, 15.6, 3.9, and 0.98 µmol/L. The organoids were exposed to oxaliplatin at 42℃ for 30 minutes and to lobaplatin at 42℃ for 60 minutes. Dose-response curves of responses to in vitro hyperthermic perfusion with these two drugs were constructed and evaluated. Clinical doses of oxaliplatin and lobaplatin were further tested on 30 organoids. This testing revealed oxaliplatin was effective at 579 µmol/L at a hyperthermic perfusion temperature of 42℃ for 30 min and lobaplatin was effective at 240 µmol/L at a hyperthermic perfusion temperature of 42℃ for 60 minutes. Result: Thirty-two tumor organoids were cultured from samples of colorectal cancer. The median concentration required for oxaliplatin to eliminate 50% of tumor cells (IC50) was 577.45 µmol/L (IQR: 1846.09 µmol/L). The median IC50 for lobaplatin was 85.04 µmol/L (IQR: 305.01 µmol/L).The difference between the two groups was not statistically significant (Z=1.784, P=0.084). In seven of 10 organoids, lobaplatin showed a greater IC50 after in vitro hyperthermic perfusion than did oxaliplatin. Testing of 30 organoids with clinical doses of oxaliplatin and lobaplatin revealed that oxaliplatin achieved an average inhibition rate of 39.6% (95%CI: 32.1%‒47.0%), whereas the average rate of inhibition for lobaplatin was 89.7% (95%CI: 87.0%‒92.3%): this difference is statistically significant (t=‒15.282, P<0.001). Conclusion: The rate of inhibition achieved by hyperthermic perfusion of lobaplatin in vitro is better than that achieved by hyperthermic perfusion with oxaliplatin. Lobaplatin is more effective than oxaliplatin when administered by hyperthermic intraperitoneal perfusion and therefore has the potential to replace oxaliplatin in this setting.

[Analysis of factors influencing the success rate of organoid culture in 1231 cases of colorectal cancer].

Objective: To investigate the risk factors for organoid culture failure in colorectal cancer. Methods: This was a retrospective observational study. Tumor specimens were obtained from 1130 patients with colorectal cancer who had undergone surgery or biopsy and had no other concurrent malignancies at Nanfang Hospital of Southern Medical University from December 2021 to November 2022. Organoid culture was performed on 1231 tumor tissue samples. Univariate analysis and multivariate logistic regression were used to analyze the factors that might have influenced the rate of successful organoid culture of colorectal cancer tissue samples. Results: The median (range) duration of organoid culture was 7 (3-12) days. The overall rate of successful culture was 76.3% (939/1231). The rate of successful organoid cultures varied according to the sampling site, malignant ascites having the highest success rate (96.4%, 27/28), followed by liver metastases (83.1%, 54/65), lung metastases (8/10), primary tumors (76.0%, 816/1074), omental metastases (10/14), peritoneal metastases (61.5%, 16/26), ovarian metastases (3/5), and lymph node metastases (5/9). The difference in rates of successful organoid culture between primary tumors and malignant ascites was statistically significant (P=0.012), whereas none of the other rates of successful organoid culture success differed significantly (all P>0.05). The rate of successful organoid culture was 96.4% (27/28) for malignant ascites obtained by abdominal puncture, 76.5% (864/1130) for surgical specimens, and 65.8% (48/73) for endoscopic biopsies; these differences are statistically significant (χ2=10.773, P=0.005). The rate of successful organoid culture was 62.5% (40/64) in the neoadjuvant chemoradiotherapy group, which is significantly lower than in the non-adjuvant (76.9%, 787/1023) and chemotherapy groups (77.8%, 112/144) (χ2=7.134, P=0.028). Multivariate logistic regression analysis revealed that endoscopic biopsy (OR=0.557, 95%CI: 0.335-0.924, P=0.024) and neoadjuvant chemoradiotherapy (OR=0.483, 95%CI: 0.285-0.820, P=0.007) were independent risk factors for failure of organoid culture of colorectal cancer samples. Malignant ascites (OR=8.537, 95%CI:1.154-63.131,P=0.036) and abdominal puncture (OR=8.294, 95% CI: 1.112-61.882, P=0.039) were identified as independent protective factors. Conclusions: The rate of successful organoid culture was influenced by the sampling site, sampling method, and chemoradiotherapy. The rate of successful organoid culture was lower for endoscopic biopsies and in patients receiving preoperative neoadjuvant chemoradiotherapy, and higher for malignant ascites. We consider that culture of malignant ascites is preferable when peritoneal metastases are suspected.

Cleavage of bid may amplify caspase-8-induced neuronal death following focally evoked limbic seizures.

The mechanism by which seizures induce neuronal death is not completely understood. Caspase-8 is a key initiator of apoptosis via extrinsic, death receptor-mediated pathways; we therefore investigated its role in mediating seizure-induced neuronal death evoked by unilateral kainic acid injection into the amygdala of the rat, terminated after 40 min by diazepam. We demonstrate that cleaved (p18) caspase-8 was detectable immediately following seizure termination coincident with an increase in cleavage of the substrate Ile-Glu-Thr-Asp (IETD)-p-nitroanilide and the appearance of cleaved (p15) Bid. Expression of Fas and FADD, components of death receptor signaling, was increased following seizures. In vivo intracerebroventricular z-IETD-fluoromethyl ketone administration significantly reduced seizure-induced activities of caspases 8, 9, and 3 as well as reducing Bid and caspase-9 cleavage, cytochrome c release, DNA fragmentation, and neuronal death. These data suggest that intervention in caspase-8 and/or death receptor signaling may confer protection on the brain from the injurious effects of seizures.

Increased Bcl-w expression following focally evoked limbic seizures in the rat.

Control of seizure-induced neuronal death may involve members of the Bcl-2 family of cell death regulating proteins. Bcl-w is a newly described anti-apoptotic member of this family that may confer neuroprotective effects. We therefore investigated Bcl-w expression in rat brain following focally evoked limbic seizures. Seizures were induced by unilateral microinjection of kainic acid into the amygdala of the rat and terminated after 40 min by diazepam. Constitutive Bcl-w expression was detected by Western blotting and immunohistochemistry. Bcl-w expression was increased 4-72 h following seizures within the injured hippocampus. Immunohistochemistry determined Bcl-w was predominantly expressed in neurons and seizures increased Bcl-w immunoreactivity within piriform cortex and surviving regions of the injured hippocampus. These data suggest Bcl-w may be involved in the modulation of seizure-induced brain injury.

Caspase-2 activation is redundant during seizure-induced neuronal death.

Seizure-induced neuronal death may be under the control of the caspase family of cell death proteases. We examined the role of caspase-2 in a model of focally evoked limbic seizures with continuous EEG recording. Seizures were elicited by microinjection of kainic acid into the amygdala of the rat and terminated after 40 min by diazepam. Caspase-2 was constitutively present in brain, mostly within neurons, and was detected in both cytoplasm and nucleus. Cleaved caspase-2 (12 kDa) was detected immediately following seizure termination within injured ipsilateral hippocampus, contiguous with increased Val-Asp-Val-Ala-Asp (VDVADase) activity, a putative measure of activated caspase-2. Expression of receptor interacting protein (RIP)-associated Ich-1-homologous protein with death domain (RAIDD) was increased following seizures, whereas expression of RIP and tumor necrosis factor receptor associated protein with death domain (TRADD), other components thought to be linked to the caspase-2 activation and signaling mechanism, were unchanged. Intracerebroventricular administration of z-VDVAD-fluoromethyl ketone blocked seizure-induced caspase-2 activity but did not alter caspase-8 activity and failed to affect DNA fragmentation or neuronal death. These data support activation of caspase-2 following seizures but suggest that parallel caspase pathways may circumvent deficits in caspase-2 function to complete the cell death process.