Discovery of a potent inhibitor of chaperone-mediated autophagy that targets the HSC70-LAMP2A interaction in non-small cell lung cancer cells.

BACKGROUND AND PURPOSE: Chaperone-mediated autophagy (CMA) is a selective type of autophagy targeting protein degradation and maintains high activity in many malignancies. Inhibition of the combination of HSC70 and LAMP2A can potently block CMA. At present, knockdown of LAMP2A remains the most specific method for inhibiting CMA and chemical inhibitors against CMA have not yet been discovered. EXPERIMENTAL APPROACH: Levels of CMA in non-small cell lung cancer (NSCLC) tissue samples were confirmed by tyramide signal amplification dual immunofluorescence assay. High-content screening was performed based on CMA activity, to identify potential inhibitors of CMA. Inhibitor targets were determined by drug affinity responsive target stability-mass spectrum and confirmed by protein mass spectrometry. CMA was inhibited and activated to elucidate the molecular mechanism of the CMA inhibitor. KEY RESULTS: Suppression of interactions between HSC70 and LAMP2A blocked CMA in NSCLC, restraining tumour growth. Polyphyllin D (PPD) was identified as a targeted CMA small-molecule inhibitor through disrupting HSC70-LAMP2A interactions. The binding sites for PPD were E129 and T278 at the nucleotide-binding domain of HSC70 and C-terminal of LAMP2A, respectively. PPD accelerated unfolded protein generation to induce reactive oxygen species (ROS) accumulation by inhibiting HSC70-LAMP2A-eIF2α signalling axis. Also, PPD prevented regulatory compensation of macroautophagy induced by CMA inhibition via blocking the STX17-SNAP29-VAMP8 signalling axis. CONCLUSIONS AND IMPLICATIONS: PPD is a targeted CMA inhibitor that blocked both HSC70-LAMP2A interactions and LAMP2A homo-multimerization. CMA suppression without increasing the regulatory compensation from macroautophagy is a good strategy for NSCLC therapy.

Evaluation of intra- and post-operative outcomes to compare robot-assisted surgery and conventional laparoscopy for gynecologic oncology.

OBJECTIVE: To compare robot-assisted surgery and conventional laparoscopy for gynecologic oncology regarding intra- and post-operative outcomes. METHODS: A retrospective study was performed on consecutive patients with gynecologic oncology from February 2014 to October 2017 at Gansu Provincial Hospital, China. Multivariable linear and logistic regression models were performed to explore the difference between two surgeries in the surgical outcomes after adjusting for potential confounders. RESULTS: 276 women were included in this study: 153 robot-assisted surgeries and 123 conventional laparoscopies. The multivariable linear regression model showed that robot-assisted surgery was longer operative time [coefficient (coef), 33.76; 95% CI, 12.47, 55.05; P = 0.002) ], higher lymph node yield (coef, 10.41; 95% CI, 7.47, 13.35; P < 0.001), shorter time to early post-operative feeding (coef, -1.09; 95% CI, -1.33, -0.84; P < 0.001) and less post-operative drainage volume (coef, -368.77; 95% CI, -542.46, -195.09; P < 0.001) than conventional laparoscopy. However, no difference was observed between the two surgeries regarding the estimated blood loss (P > 0.05). The multivariable logistic regression model showed that post-operative complications were similar between robot-assisted surgery and conventional laparoscopy (P > 0.05). CONCLUSION: Robot-assisted surgery was superior to conventional laparoscopy regarding intra- and post-operative outcomes for gynecologic oncology.

[Influence of different duration of waterlogging on the growth and C and N metabolism of soybean at seedling and flowering stages].

A pot experiment with soybean cultivar Nannong 99-6 was conducted to study its growth and C and N metabolism at seedling and flowering stages under the stress of different duration of waterlogging. Waterlogging inhibited the soybean growth. The plant biomass, leaf area, leaf pigment content, and photosynthesis rate all decreased significantly, and the leaf malonyldialdehyde (MDA) content had a significant increase. The change ranges of the physiological indices increased with increasing waterlogging duration. After the release of the stress, the plants had some recovery. The recovery capability in treatment waterlogging for 10 d was stronger than that in the treatment waterlogging for 20 d. The leaf soluble C and N and key enzymes had different responses to waterlogging. Soluble sugar content and glutamine synthease and sucrose synthease activities all increased, but soluble protein content decreased. The influence of waterlogging on the plant biomass, leaf area, and MDA content was smaller at seedling stage than at flowering stage. It was suggested that the shorter the waterlogging duration was, the lesser damage the soybean plant suffered, and the stronger the recovery capability was. Soybean plant could recover itself after waterlogging for 10 d.

[Effects of simulated acid rain on oilseed rape (Brassica napus) physiological characteristics at flowering stage and yield].

A pot experiment was conducted to study the effects of different acidity simulated acid rain on the physiological characteristics at flowering stage and yield of oilseed rape (B. napus cv. Qinyou 9). Comparing with the control (pH 6.0), weak acidity (pH = 4.0-5.0) simulated acid rain stimulated the rape growth to some extent, but had less effects on the plant biomass, leaf chlorophyll content, photosynthetic characteristics, and yield. With the further increase of acid rain acidity, the plant biomass, leaf chlorophyll content, photosynthetic rate, antioxidative enzyme activities, and non-enzyme antioxidant contents all decreased gradually, while the leaf malonyldialdehyde (MDA) content and relative conductivity increased significantly. As the results, the pod number per plant, seed number per pod, seed weight, and actual yield decreased. However, different yield components showed different sensitivity to simulated acid rain. With the increasing acidity of simulated acid rain, the pod number per plant and the seed number per pod decreased significantly, while the seed weight was less affected.