Synergistic effects of eukaryotic co-expression plasmid-based STAT3-specific siRNA and LKB1 on ovarian cancer in vitro and in vivo
Authors: Xinyue Zhang
Ruizhi Liu
Liqun Zhang
Yuan Pan
Journal: Oncology Reports (2015)
Discipline: CLINICAL MEDICINE
Keywords: STAT3; ovarian cancer; shRNA; LKB1; synergistic effects
Affiliations: Center for Reproductive Medicine, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China.

Abstract:  The signal transducer and activator of transcription 3 (STAT3) are ideal targets for ovarian cancer. Previous studies showed that downregulation of STAT3 using specific short hairpin RNAs (shRNA) can significantly reduce ovarian tumor growth. However, RNA interference does not fully ablate target gene expression due to idiosyncrasies associated with shRNAs and their targets. To enhance the therapeutic efficacy of STAT3-specific shRNA, we employed a combinatorial expression of STAT3-specific shRNA and liver kinase B1 (LKB1), a tumor suppressor. Thus, the LKB1 coding sequences and STAT3-specific shRNAs were constructed in a eukaryotic co-expression plasmid pCDNA3.1, and then transfected into ovarian cancer cells to evaluate the synergistic effects of this combination on anticancer activity and explore the relevant molecular mechanisms. Co-expression of STAT3‑specific siRNA and LKB1 (pSi-STAT3-LKB1) synergistically inhibited ovarian cancer cell growth, invasion and migration, induced cell apoptosis and arrested the cell cycle in vitro when compared with monotherapy. The results showed that the co-expression of plasmid pSi-STAT3-LKB1 inserted subcutaneously into ovarian tumor xenograft resulted in more significant inhibition of tumor growth. Further study showed that the synergistic anti-ovarian cancer effects of the co-expression of STAT3-specific siRNA and LKB1 may be associated with the upregulation of p-p53, p21 and downregulation of survivin, BCL-2 and cyclin D1. Results of the present study suggested that combined therapy with eukaryotic co-expression of the plasmid‑carrying STAT3-specific siRNA and LKB1 is a novel and efficient treatment strategy for human ovarian cancer. 

Retracted: Yes

PubPeer comments:
 Fig 6D.  Western blot analysis for STAT3 and LKB1 in tumor tissues following treatment with various plasmids . ![file] As [discussed e.g. here] , the loading control has appeared in any number of other studies. E.g. Fig 6D from [Wen et al (2015)] . ![] Fragments of the substantive bands also appear elsewhere, differently arranged. *[above]* Fig 5B from [Dong et al (2016)] ; *[below]* 4C from Wen et al (2015). ![] , 
 Fig 1C.  Western blot analysis for STAT3 and LKB1 in SKVO3 cells transfected with different recombinant treatment plasmids. ![file] Another versatile loading control. Compare with e.g. Fig 5D of [Wen et al (2015)] . ![] , 
 Fig 5.  Effect of co-expression of pSi-STAT3-LKB1 plasmid on relevant tumor effector molecules in vitro. SKOV3 cells were transfected with different recombinant treatment plasmids. Non-transfection was used as a negative control. At 48 h after transfection, the cells were collected and protein levels of p21, p-p53, cyclin D1, survivin and Bcl-2 were analyzed by western blotting using specific antibodies. ![file] Red-boxed band seems to have strayed from Fig 3E of [Liu et al (2015)] . More manifestations are linked in that thread. ![file] Survivin band bears a high similarity to ADAM-9 from Fig 1C of [Chang et al (2016)] . After a horizontal flip, both bands have much in common with ADAM-10 from Fig 5D of [Liu et al (2016)] . ![file] , 
 The concept of a  eukaryotic co-expression plasmid being developed and used to cure cancer is weird. Eukaryotes are a broad church. *Giardia lamblia* and *Entamoba histolytica* are unicellular eukaryotes and we would probably not want to cure them of cancer, even if they could get it. And much as I love all creatures great and small including but not limited to dugongs, echidnas, kias, scorpions, rattlesnakes and liver flukes (ok, maybe not liver flukes), notwithstanding the optimistic claims of the present paper, we are struggling to cure cancer in meeces, let alone humans. So a one size fits all eukaryotic coexpression plasmid for cancer therapy seems a bit of a misnomer. Curiously, another synergistic-effects-of-eukaryotic-coexpression-plasmid-curing-cancer article is referenced. No common authors, at least in the listed set. Different hospitals. https: pubmed.ncbi.nlm.nih.gov 24659339 Might there be FACS plot reuse in Fig. 1? Might there be microscopy duplication in Fig. 2? You decide! , 
 #4 I understand  eukaryotic co-expression plasmid to be simply a convenient delivery vehicle for genetic payloads designed to be hostile to a targeted cancer. People who enjoyed this paper also enjoyed  Synergistic effects of co-expression plasmidu2011based ADAM10-specific siRNA and GRIM-19 on hepatocellular carcinoma in vitro and in vivo [(Liu et al 2014)] and  Additive effects of eukaryotic cou2011expression plasmid carrying GRIMu201119 and LKB1 genes on breast cancer in vitro and in vivo [(Zhang et al 2015)] . , 
 #3 Figs 4D and 5. ![file] MMP-9 or Bcl-2? , 
 *[left]* Fig 1C.  Western blot analysis for STAT3 and LKB1 in SKVO3 cells transfected with different recombinant treatment plasmids. *[right]* Fig 1C from [Zhang et al (2015)] .  Western blot analysis of the protein expression of GRIM-19 72 h after transfection. ![file] , 
 *[right]* Fig 5 again. *[left]* Fig 3F from [Zhao et al (2017)] .  c-MET expression at the ... protein level was determined by ... western blot analysis of four MM cell lines and plasma from normal individuals . ![file] Unexpected similarities. , 
 Retracted [21 July 2021] . ----------------------------------- Following the publication of this paper, it was drawn to the Editors attention by a concerned reader that certain of the western blotting data shown in Figs. 1C and 6D bore unexpected similarities to data appearing in different form in other articles by different authors. Owing to the fact that some of the contentious data in the above article had already been published elsewhere, or were already under consideration for publication, prior to its submission to *Oncology Reports*, the Editor has decided that this paper should be retracted from the Journal. The authors agree with the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. ,