Fig 1: MMP-12 expression level becomes increasingly elevated as prostate cancer progresses: A, The MMP-12 protein expression (left) and quantification (right) in patients with pathological stages of benign prostatic hyperplasia (BPH), androgen-dependent prostate cancer (ADPC), and castration-resistant prostate cancer (CRPC) was determined by immunohistochemistry (scale bar 100 μm). B, The concentration of MMP-12 protein in the serum of the different groups of patients was determined by ELISA. Data are reported as means±SD. **P<0.01, ***P<0.001, and ****P<0.0001 unpaired t-test. ns: not significant.
Fig 2: The silencing of MMP-12 attenuated castration-resistant prostate cancer (CRPC) cell migration and invasion by alleviating lipid catabolism and promoting autophagy. A, The migration and invasion of CRPC cells were evaluated by transwell assay without or with Matrigel-coated under a co-culture condition (scale bar 100 μm). B, Cancer invasion-related MMP-7 and MMP-9, lipolysis-related CD36 and CPT1, and autophagy-related P62 and LC3B were detected by western blotting in individual groups. C, The LC3 protein expression in co-cultured C42B cells was detected by immunofluorescence staining (scale bar 5 μm). Results represent three independent experiments. Data are reported as means±SD. *P<0.05, **P<0.01, ***P<0.001, and ****P<0.0001 unpaired t-test. siMMP-12: siRNA silenced MMP-12; siNT: non-targeted siRNA.
Fig 3: Silence of MMP-12 could maintain the adipocytes' mature state. A, The MMP-12 protein in C42B and PC3 cell lines was detected by western immunoblotting. B, Relative mRNA expression of aP2 and MMP-12 in preadipocytes 3T3-L1 and mature adipocytes. C, siRNA silenced MMP-12 (siMMP-12) protein expression in C42B and PC3 cell lines. D, The concentration of MMP-12 protein in the culture medium was measured by ELISA in both C42B and PC3 cell groups. E, The mature adipocyte area was validated by Oil red O staining in the co-culture system in both C42B and PC3 cell groups (scale bar 200 μm). F, MMP-12 expression was evaluated in C42B and PC3 cells cultivated with mature adipocytes compared with preadipocytes 3T3-L1, while it was silenced by siRNA treatment. G, aP2 expression was elevated in mature adipocytes compared with 3T3-L1 when co-cultivated with castration-resistant prostate cancer (CRPC) cells, and levels were even higher with siMMP-12 treatment. Results represent three independent experiments. Data are reported as means±SD. *P<0.05, **P<0.01, ***P<0.001, and ****P<0.0001 unpaired t-test. ns: not significant; siNT: non-targeted siRNA.
Fig 4: The loss of MMP-12 inhibited mice castration-resistant prostate cancer (CRPC) tumor growth. A, Timeline of the mouse experiment. B, Relative tumor weight was measured in different groups at the end of the experiment. C, Tumor volume was measured by caliper in these three groups at 7, 14, and 21 days. D, The C42B tumor gross appearances are shown and LC3 protein was detected and quantified by immunohistochemical staining (scale bar 100 μm). E, Autophagy-related P62 and LC3B and lipolysis-related CD36 and CPT1 were detected by western blotting in tumor tissues (5 mice/group). Data are reported as means±SD. **P<0.01, ***P<0.001, and ****P<0.0001 unpaired t-test. ns: not significant. siMMP-12: siRNA silenced MMP-12; siNT: non-targeted siRNA.
Fig 5: Potential mechanism of MMP-12 promoting the progression of castration-resistant prostate cancer (CRPC) cells. MMP-12 secreted by tumor cells might interact with surrounding adipocytes, leading to the release of free lipids, thereby promoting the uptake and utilization of lipids by tumor cells. MMP-12 might also alternatively restrain the autophagy process of cancer cells, thus promoting the migration and invasion of CRPC cells.
Supplier Page from Abcam for Human MMP12 ELISA Kit