Test on Novel Antimetastasis Therapy Targeting Mitocytosis

Question 1: The study's in vivo experiments confirmed that RH-NPs had a significantly lower ability to target circulating tumor cells compared to RP-NPs.

A. Yes

B. No

Explanation: The study utilized a blood circulation mimetic device (an in vitro setup) to investigate the targeting ability of nanoparticles to circulating tumor cells, not in vivo experiments. The results from this device showed that the CTC uptake of RH-NPs was 1.86-fold higher than that of RP-NPs, demonstrating an enhanced ability, not a significantly lower one.

Question 2: How was the progression of tumor hematogenous metastasis in the lungs of 4T1-Luc inoculated Balb/c mice primarily assessed?

A. By measuring tumor volume using a caliper until day 27.

B. Through bioluminescence images taken with an IVIS Spectrum Imaging System on days 4 and 10.

C. By analyzing migrasome characteristic protein TSPAN4 in 4T1 cells.

D. Via statistical analysis of tumor metastatic lung nodules from excised lungs.

Explanation: The study materials state that 'Bioluminescence images were taken using an IVIS Spectrum Imaging System (PerkinElmer Ltd.) on days 4 and 10 to assess the lung metastatic progression of 4T1-Luc.' Additionally, for tumor metastatic lung nodules, the materials mention '(K) statistical analysis of tumor metastatic lung nodules,' indicating that this was also a method of assessment from excised lungs. Measuring tumor volume until day 27 was for an orthotopic breast cancer model, not specifically lung metastasis assessment. Analyzing TSPAN4 was for investigating migrasome activation in cells, not direct assessment of lung metastasis progression.

Question 3: The expression level of the migrasome characteristic protein TSPAN4 is highest in normal L02 cells compared to highly migratory 4T1 cells.

A. Yes

B. No

Explanation: The study materials state that the expression of migrasome characteristic protein TSPAN4 was highest in highly migratory 4T1 cells, followed by moderately migratory E0771 cells, then weakly migratory EMT6 cells, and finally normal L02 cells, which had the lowest expression.

Question 4: According to the study materials, why was an indirect approach developed for delivering the integrin inhibitor CGT to migrasomes?

A. Integrins are not expressed in tumor cells, making direct targeting ineffective.

B. Integrins are ubiquitously expressed in tumors, so direct delivery of CGT would not specifically suppress migrasome biogenesis.

C. CGT can only inhibit integrins when co-transported with damaged mitochondria.

D. There was no direct migrasome-targeting strategy available to ensure therapeutic efficiency.

Explanation: The study states that 'as integrins are ubiquitously expressed in tumors, simply delivering CGT to tumor sites might not specifically disrupt migrasome biogenesis for effective mitocytosis suppression.' It also notes, 'Critically, the absence of direct migrasome-targeting strategies leads us to develop an indirect approach.' Therefore, both ubiquitous integrin expression and the lack of direct targeting strategies necessitated an indirect delivery method for CGT.

Question 5: Real-time bioluminescence imaging of lung metastasis for 4T1-luc tumor cells in Balb/c mice was conducted on day 5.

A. Yes

B. No

Explanation: The study materials indicate that real-time bioluminescence imaging of lung metastasis for 4T1-luc tumor cells in Balb/c mice was performed on days 4 and 10, not day 5.